| 1. |
- Alhadad, Alaa, et al.
(författare)
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The value of tomographic ventilation/perfusion scintigraphy (V/PSPECT) for follow-up and prediction of recurrence in pulmonary embolism.
- 2012
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Ingår i: Thrombosis Research. - : Elsevier BV. - 1879-2472 .- 0049-3848.
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Pulmonary embolism (PE) is diagnosed with imaging techniques such as ventilation/perfusion (V/P) lung scintigraphy or multidetector computed tomography of the pulmonary arteries (MDCT). Lung scintigraphy can be performed with planar (V/P PLANAR) and tomographic (V/P SPECT) techniques. V/P SPECT has higher sensitivity and specificity than V/P PLANAR. As nephrotoxic contrast media are not used during V/P SPECT, examinations can be repeated for evaluation of resolution of perfusion defects after PE. However, the value of residual perfusion defects identified using V/P SPECT for the prediction of recurrent PE has not been thoroughly evaluated. MATERIAL AND METHODS: We evaluated resolution and recurrence of PE in 227patients (mean age 63±17years, 134[59%] women) with PE undergoing ≥2 SPECT examinations in 2005-2007. PE was defined as minor (<20% perfusion defect on SPECT, n=86), medium (20-50% perfusion defect on SPECT, n=99), or major (>50% perfusion defect on SPECT, n=42). RESULTS: At second V/P SPECT examination, complete resolution of perfusion defects had occurred in 45 (52%) patients with minor PE after 8.2±7.4months, in 29 (29%) of patients with medium PE after 6.2±5.9months, and in 2(5%) of patients with major PE after 6.5±0.7months. During 47±24months of follow up, 37(16 %) patients suffered recurrent PE. Of these 37, 34 (92%) showed residual perfusion defects at the second V/P SPECT examination. Recurrence of PE was also predicted by advanced age and female gender. However, in multivariate regression analysis, recurrence was only predicted by age (p=0.0013) and residual perfusion defect on V/P SPECT (p=0.0039). CONCLUSION: In conclusion, complete resolution of PE was common in patients with minor PE, whereas residual perfusion defects were widespread in patients with medium and major PE. PE patients identified with persistent perfusion defects at follow-up SPECT have a high risk of PE recurrence.
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| 2. |
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| 3. |
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| 4. |
- Bajc, Marika, et al.
(författare)
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99mTc-DMSA renal scintigraphy during kidney maturation
- 1995
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Ingår i: Clinical Nuclear Medicine. - 0363-9762. ; 20:3, s. 211-214
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Tidskriftsartikel (refereegranskat)abstract
- A total of 282 renal scintigrams with Tc-99m DMSA in 238 children ranging in age from 10 days to 13 years performed during a 3-year period were reviewed. The authors present 94 kidneys in 85 children in whom no sign of pathology was demonstrated clinically, either by ultrasound or intravenous urography, or by micturating urethrocystography. By exploring homogeneity or heterogeneity of tracer distribution, kidney length, and background level, the authors were able to identify a "normal" pattern of tracer distribution according to age. They found that the average kidney length was 56 mm at birth, growing 1 mm per month during the first year of life, and 4 mm per year thereafter, until puberty. Average background activity was 14% of the average kidney activity at birth which decreased to approximately 6% during the first year of life, with no further decrease thereafter.
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| 5. |
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| 6. |
- Bajc, Marika, et al.
(författare)
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Assessment of Ventilation and Perfusion in Patients with COVID-19 Discloses Unique Information of Pulmonary Function to a Clinician : Case Reports of V/P SPECT
- 2021
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Ingår i: Clinical Medicine Insights: Circulatory, Respiratory and Pulmonary Medicine. - : SAGE Publications. - 1179-5484. ; 15
-
Tidskriftsartikel (refereegranskat)abstract
- V/P SPECT from 4 consecutive patients with COVID-19 suggests that ventilation and perfusion images may be applied to diagnose or exclude pulmonary embolism, verify nonsegmental diversion of perfusion from the ventilated areas (dead space ventilation) that may represent inflammation of the pulmonary vasculature, detect the reversed mismatch of poor ventilation and better preserved perfusion (shunt perfusion) in bilateral pulmonary inflammation and indicate redistribution of lung perfusion (antigravitational hyperperfusion) due to cardiac congestion. V/P mismatch and reversed mismatch may be extensive enough to diminish dramatically preserved matching ventilation/perfusion and to induce severe hypoxemia in COVID-19.
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| 7. |
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| 8. |
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| 9. |
- Bajc, Marika, et al.
(författare)
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EANM guidelines for ventilation/perfusion scintigraphy : Part 1. Pulmonary imaging with ventilation/perfusion single photon emission tomography.
- 2009
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 36:8, s. 1356-1370
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Tidskriftsartikel (refereegranskat)abstract
- Pulmonary embolism (PE) can only be diagnosed with imaging techniques, which in practice is performed using ventilation/perfusion scintigraphy (V/P(SCAN)) or multidetector computed tomography of the pulmonary arteries (MDCT). The epidemiology, natural history, pathophysiology and clinical presentation of PE are briefly reviewed. The primary objective of Part 1 of the Task Group's report was to develop a methodological approach to and interpretation criteria for PE. The basic principle for the diagnosis of PE based upon V/P(SCAN) is to recognize lung segments or subsegments without perfusion but preserved ventilation, i.e. mismatch. Ventilation studies are in general performed after inhalation of Krypton or technetium-labelled aerosol of diethylene triamine pentaacetic acid (DTPA) or Technegas. Perfusion studies are performed after intravenous injection of macroaggregated human albumin. Radiation exposure using documented isotope doses is 1.2-2 mSv. Planar and tomographic techniques (V/P(PLANAR) and V/P(SPECT)) are analysed. V/P(SPECT) has higher sensitivity and specificity than V/P(PLANAR). The interpretation of either V/P(PLANAR) or V/P(SPECT) should follow holistic principles rather than obsolete probabilistic rules. PE should be reported when mismatch of more than one subsegment is found. For the diagnosis of chronic PE, V/P(SCAN) is of value. The additional diagnostic yield from V/P(SCAN) includes chronic obstructive lung disease (COPD), heart failure and pneumonia. Pitfalls in V/P(SCAN) interpretation are considered. V/P(SPECT) is strongly preferred to V/P(PLANAR) as the former permits the accurate diagnosis of PE even in the presence of comorbid diseases such as COPD and pneumonia. Technegas is preferred to DTPA in patients with COPD.
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| 10. |
- Bajc, Marika, et al.
(författare)
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EANM guidelines for ventilation/perfusion scintigraphy : Part 2. Algorithms and clinical considerations for diagnosis of pulmonary emboli with V/P(SPECT) and MDCT.
- 2009
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089.
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Tidskriftsartikel (refereegranskat)abstract
- As emphasized in Part 1 of these guidelines, the diagnosis of pulmonary embolism (PE) is confirmed or refuted using ventilation/perfusion scintigraphy (V/P(SCAN)) or multidetector computed tomography of the pulmonary arteries (MDCT). To reduce the costs, the risks associated with false-negative and false-positive diagnoses, and unnecessary radiation exposure, preimaging assessment of clinical probability is recommended. Diagnostic accuracy is approximately equal for MDCT and planar V/P(SCAN) and better for tomography (V/P(SPECT)). V/P(SPECT) is feasible in about 99% of patients, while MDCT is often contraindicated. As MDCT is more readily available, access to both techniques is vital for the diagnosis of PE. V/P(SPECT) gives an effective radiation dose of 1.2-2 mSv. For V/P(SPECT), the effective dose is about 35-40% and the absorbed dose to the female breast 4% of the dose from MDCT performed with a dose-saving protocol. V/P(SPECT) is recommended as a first-line procedure in patients with suspected PE. It is particularly favoured in young patients, especially females, during pregnancy, and for follow-up and research.
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| 11. |
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| 12. |
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| 13. |
- Bajc, Marika, et al.
(författare)
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Hepato-pulmonary shunts
- 2022
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Ingår i: Nuclear Medicine and Molecular Imaging : Volume 1-4 - Volume 1-4. - 9780128229804 - 9780128229606 ; 2, s. 103-105
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Bokkapitel (refereegranskat)abstract
- Hepato-pulmonary shunts might develop in some patients with severe liver disease, usually when cirrhosis has developed. At this stage, a dilatation of intra-pulmonary vessels might develop causing defects in blood oxygenation. Shortness of breath is a common symptom. The disease might be asymptomatic but it has an impact of patient's quality of life. The identification of shunt dysfunction is based on the arterial blood gas test. The dilatation of pulmonary vessels and shunting index can be identified by macro aggregated albumin lung perfusion scintigraphy (99mTc-MAA) or a transthoracic contrast-enhanced echocardiography.
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| 14. |
- Bajc, Marika, et al.
(författare)
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Letter to editor
- 2020
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 47, s. 1643-1644
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 15. |
- Bajc, Marika, et al.
(författare)
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Lung ventilation/perfusion SPECT in the artificially embolized pig.
- 2002
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Ingår i: Journal of Nuclear Medicine. - 0161-5505. ; 43:5, s. 640-647
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Tidskriftsartikel (refereegranskat)abstract
- Planar lung scintigraphy is a standard method used for the diagnosis of lung embolism, but it is hampered by the high incidence of nondiagnostic tests. Ventilation/perfusion SPECT may possibly improve this situation. The objective of this study was to compare planar lung scintigraphy with ventilation/perfusion SPECT using pigs with artificially engendered lung emboli labeled with (201)Tl. METHODS: Sixteen anesthetized pigs were each injected with zero to 4 latex emboli. Cylindric emboli were used in the first 7 pigs and flat 3-tailed emboli were used in the remaining 9 pigs. The pigs spontaneously inhaled 30 MBq (99m)Tc-diethylenetriaminepentaacetic acid aerosol for ventilation scintigraphy. Planar scintigraphy and SPECT were performed using a double-head gamma camera in (99m)Tc and (201)Tl windows. Immediately thereafter, 100 MBq (99m)Tc-labeled macroaggregated albumin were injected intravenously followed by SPECT and, finally, planar scintigraphy. The ventilation background was subtracted from the perfusion tomograms for calculation of a normalized ventilation/perfusion (V/P) quotient image set. RESULTS: The cylindric emboli caused artifacts in the ventilation images; therefore, these were excluded from the final analysis. However, for the planar perfusion images of these pigs, sensitivity and specificity were 71% and 91%, respectively, whereas SPECT yielded 100% for both. For the 3-tailed emboli and ventilation/perfusion images, the sensitivity and specificity were 64% and 79%, respectively, for the planar modality, whereas SPECT yielded values of 91% and 87%, respectively. CONCLUSION: V/P SPECT may improve the diagnostic power of lung scintigraphy.
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| 16. |
- Bajc, Marika, et al.
(författare)
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Methodology for ventilation/perfusion SPECT.
- 2010
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Ingår i: Seminars in Nuclear Medicine. - : Elsevier BV. - 0001-2998. ; 40:6, s. 415-425
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Tidskriftsartikel (refereegranskat)abstract
- Ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) is the scintigraphic technique of choice for the diagnosis of pulmonary embolism and many other disorders that affect lung function. Data from recent ventilation studies show that the theoretic advantages of Technegas over radiolabeled liquid aerosols are not restricted to the presence of obstructive lung disease. Radiolabeled macroaggregated human albumin is the imaging agent of choice for perfusion scintigraphy. An optimal combination of nuclide activities and acquisition times for ventilation and perfusion, collimators, and imaging matrix yields an adequate V/Q SPECT study in approximately 20 minutes of imaging time. The recommended protocol based on the patient remaining in an unchanged position during the initial ventilation study and the perfusion study allows presentation of matching ventilation and perfusion slices in all projections as well as in rotating volume images based upon maximum intensity projections. Probabilistic interpretation of V/Q SPECT should be replaced by a holistic interpretation strategy on the basis of all relevant information about the patient and all ventilation/perfusion patterns. PE is diagnosed when there is more than one subsegment showing a V/Q mismatch representing an anatomic lung unit. Apart from pulmonary embolism, other pathologies should be identified and reported, for example, obstructive disease, heart failure, and pneumonia. Pitfalls exist both with respect to imaging technique and scan interpretation.
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| 17. |
- Bajc, Marika, et al.
(författare)
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Perfusion SPECT in patients with suspected pulmonary embolism.
- 2013
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 40:9, s. 1432-1437
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Ventilation/perfusion tomography (V/PSPECT), with new interpretation criteria and newer tracers for ventilation imaging, has markedly improved the diagnostic yield in acute pulmonary embolism (PE). Here, we evaluated the diagnostic performance of perfusion SPECT (PSPECT) without ventilation imaging. METHODS: We studied 152 patients with clinically suspected PE who had been examined with both V/PSPECT and multidetector computed tomographic angiography (MD-CTA). The diagnosis or exclusion of PE was decided by the referring clinician based on both the V/PSPECT and/or MD-CTA findings in combination with the clinical findings. PSPECT images were retrospectively examined by a physician with experience in the interpretation of planar perfusion scans who was blinded to clinical, V/PSPECT and MD-CTA data. PSPECT images were interpreted without the aid of chest radiography. All the patients who were deemed to have PE were given anticoagulant therapy. RESULTS: Of the 152 patients, 59 (39 %) received a final diagnosis of PE, and 19 (32 %) had associated cardiopulmonary diseases such as pneumonia, COPD, or left heart failure. PSPECT correctly identified 53 (90 %) of the 59 patients with PE. The specificity was 88 of 93 (95 %). None of the PSPECT images was rated nondiagnostic. PSPECT yielded an overall diagnostic accuracy of 93 % (95 % confidence interval, CI, 87-96 %). At the observed PE prevalence of 39 %, the positive and negative predictive values of PSPECT were 91 % (95 % CI, 80-97 %) and 94 % (95 % CI, 86-97 %), respectively. CONCLUSION: In managing critically ill patients, PSPECT might be a valid alternative to V/PSPECT or MD-CTA since it was able to identify most patients with PE with a low false-positive rate and no inconclusive results.
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| 18. |
- Bajc, Marika, et al.
(författare)
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Pulmonary Embolism : Ventilation/Perfusion Scintigraphy as a Proper Tool in Diagnosing Pulmonary Embolism and Frequent Pulmonary Comorbidities
- 2022
-
Ingår i: Nuclear Medicine and Molecular Imaging : Volume 1-4 - Volume 1-4. - 9780128229606 - 9780128229804 ; 2, s. 92-102
-
Bokkapitel (refereegranskat)abstract
- Ventilation/perfusion single photon emission computed tomography (V/P SPECT) is the recommended method for proper diagnosis of pulmonary embolism (PE), according to the European Association of Nuclear Medicine (EANM) guidelines. Adequate V/P SPECT acquisition starts with ventilation and continues immediately with perfusion. The whole procedure takes 20min by using an optimal combination of nuclide activities, collimators, and imaging matrix. For the ventilation studies, Technegas particles have an advantage over radiolabeled liquid aerosols due to the better penetration to the periphery. Radiolabeled macro aggregated human albumin (MAA) is the imaging agent of choice for perfusion scintigraphy. The method allows recognition of V/P pattern typical for PE, the sign of chronic obstructive pulmonary disease (COPD), pneumonia, left heart failure (LHF), chronic PE, and suspicion of other parenchymal processes like tumors. It gives a clear answer to the clinicians regarding PE. Furthermore, it is possible to quantify the extent of ventilation and perfusion changes. The radiation exposure is low, the sensitivity and specificity are above 95% and the method has no contraindications. It is possible to diagnose PE even in the presence of another pulmonary comorbidity. Hybrid V/P SPECT/CT might have additional value for tumor diagnostics.
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| 19. |
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| 20. |
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| 21. |
- Bajc, Marika, et al.
(författare)
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V/P SPECT as a diagnostic tool for pregnant women with suspected pulmonary embolism.
- 2015
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 42:8, s. 1325-1330
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of the study was to assess the prevalence of pulmonary embolism (PE) and other lung diseases among pregnant women with suspected PE and to calculate the radiation exposure to patient and fetus in this population. As a secondary aim, we evaluated the negative predictive value of a normal ventilation/perfusion single photon emission computed tomography (V/P SPECT) examination in pregnancy.
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| 22. |
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| 23. |
- Bajc, Marika
(författare)
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Ventilation/Perfusion SPECT - A New Challenge for Detection of Pulmonary Embolism. Can Multi Detector Computed Tomography Replace Lung Scintigraphy?
- 2009
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Ingår i: Current Medical Imaging Reviews. - : Bentham Science Publishers Ltd.. - 1875-6603 .- 1573-4056. ; 5:3, s. 174-179
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Forskningsöversikt (refereegranskat)abstract
- ventilation/perfusion scintigraphy (V/P-SCAN) was the procedure of choice for studying patients with suspected pulmonary embolism (PE) until the prospective evaluation of V/P imaging in the study known as PIOPED I revealed high number of non diagnostic findings. This has challenged development of computed tomography (CT) during 1990s. Since beginning of 2000, multidetector CT (MDCT) is widely applied and has become the most commonly used technique in patients with suspected PE. The current MDCT have very advanced technology and have improved ability to detect small emboli. Unfortunately, results of the most advanced MDCT are still compared with V/P-SCAN results performed in PIOPED I 20 years ago. However V/P-SCAN has further developed. Tomographic technique V/P-SPECT is taking over V/P-PLANAR. Probabilistic criteria are replaced by holistic criteria for interpretation, taking lessons learned from PIOPED I. Discussion is focused on diagnostic value for MDCT and V/P-SPECT. MDCT and V/P-SPECT are both indispensible imaging techniques to study patients with suspected PE. However, when available, V/P-SPECT should be the preferred method for diagnosis of PE, primarily due to the lower radiation exposure and applicability to all patients. Therefore it is our duty to make V/P-SPECT generally more available, to use holistic interpretation knowledge and to communicate daily with the clinicians, so that the best technique is used in all patients. In conclusion MDCT cannot replace V/P-SPECT. MDCT and V/P-SPECT are complementary rather the competitive!
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| 24. |
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| 25. |
- Bajc, Marika, et al.
(författare)
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Ventilation/Perfusion SPECT for Diagnosis of Pulmonary Embolism and Other Diseases.
- 2011
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Ingår i: International Journal of Molecular Imaging. - : Hindawi Limited. - 2090-1712 .- 2090-1720. ; 2011:Dec 19
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Tidskriftsartikel (refereegranskat)abstract
- V/P(SPECT) has the potential to become a first hand tool for diagnosis of pulmonary embolism based on standardized technology and new holistic interpretation criteria. Pretest probability helps clinicians choose the most appropriate objective test for diagnosis or exclusion of PE. Interpretation should also take into account all ventilation and perfusion patterns allowing diagnosis of other cardiopulmonary diseases than PE. In such contexts, V/P(SPECT) has excellent sensitivity and specificity. Nondiagnostic reports are ≤3%. V/P(SPECT) has no contraindication; it is noninvasive and has very low radiation exposure. Moreover, acquisition time for V/P(SPECT) is only 20 minutes. It allows quantification of PE extension which has an impact on individual treatment. It is uniquely useful for followup and research.
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| 26. |
- Bajc, Marika, et al.
(författare)
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Ventilation/Perfusion SPECT for diagnostics of pulmonary embolism in clinical practice.
- 2008
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Ingår i: Journal of Internal Medicine. - : Wiley. - 1365-2796 .- 0954-6820. ; 264:4, s. 379-387
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Tidskriftsartikel (refereegranskat)abstract
- AIM: The aim of this retrospective study is to illustrate clinical utility and impact of pulmonary embolism (PE) diagnostics of up to date Ventilation/Perfusion SPECT (V/P (SPECT)) applying holistic interpretation criteria. MATERIAL AND METHODS: During a 2-year period 2328 consecutive patients referred to V/P(SPECT) for clinically suspected PE were examined. Final diagnosis was established by physicians clinically responsible for patient care. To establish the performance of V/P(SPECT) negative for PE, patients were followed up by medical records for 6 months. RESULTS: Ventilation/Perfusion SPECT was feasible in 99% of the patients. Data for follow-up were available in 1785 patients (77%). PE was reported in 607 patients (34%). Normal pattern was described in 420 patients (25%). Pathology other than PE such as a pneumonia, left heart failure, obstructive lung disease, tumour was described in 724 patients (41%). Report was nondiagnostic in 19 patients (1%). Six cases were classified as falsely negative because PE was diagnosed at follow-up and was fatal in one case. Six cases were classified as falsely positive because the clinician decided not to treat. In 608 patients with final PE diagnosis, 601 patients had positive V/P(SPECT) (99%). In 1177 patients without final PE diagnosis 1153 patients had negative V/P(SPECT) (98%). CONCLUSIONS: Holistic interpretation of V/P(SPECT,) yields high negative and positive predictive values and only 1% of nondiagnostic findings and was feasible in 99% of patients. It is a responsibility and a challenge of nuclear medicine to provide optimal care of patients with suspected PE by making V/P(SPECT) available.
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| 27. |
- Begic, A, et al.
(författare)
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Ancillary findings assessed by ventilation/perfusion tomography. Impact and clinical outcome in patients with suspected pulmonary embolism.
- 2015
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Ingår i: Nuklearmedizin. - 0029-5566. ; 54:5, s. 223-230
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Tidskriftsartikel (refereegranskat)abstract
- Ventilation/perfusion tomography (V/P SPECT) is a recommended method for diagnosing and follow-up of pulmonary embolism (PE). Moreover, it is possible to recognize other pathologies in addition to PE, such as pneumonia, COPD and left heart failure (LHF). The objective of this prospective study was to identify frequency of ancillary findings among patients with suspected PE. Patients, material, method: 331 consecutive patients with suspected PE were examined and classified with V/P SPECT. Patients were followed up clinically and by means of other laboratory tests.
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| 28. |
- Begic, Amela, et al.
(författare)
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Impact of ventilation/perfusion single-photon emission computed tomography on treatment duration of pulmonary embolism.
- 2015
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Ingår i: Nuclear Medicine Communications. - 1473-5628. ; 36:2, s. 162-167
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Tidskriftsartikel (refereegranskat)abstract
- The aim of the study was to establish whether the duration of anticoagulant (AC) therapy can be tailored, on an objective basis, by using ventilation/perfusion single-photon emission computed tomography (V/P SPECT) and to assess the extent of residual perfusion defects over time. In particular, we addressed the following: (a) is the extent of perfusion recovery at 3 months of initial pulmonary embolism (PE) diagnosis a satisfactory criterion for deciding the duration of oral AC? (b) Is it safe to withdraw AC at 3 months if perfusion recovery is complete?
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| 29. |
- Begic, Amela, et al.
(författare)
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Tomographic ventilation/perfusion lung scintigraphy in the monitoring of the effect of treatment in pulmonary embolism: serial follow-up over a 6-month period.
- 2011
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Ingår i: Nuclear Medicine Communications. - 1473-5628. ; 32, s. 508-514
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Pulmonary embolism (PE) is a severe condition with nonspecific symptoms. Diagnosis relies on medical imaging but follow-up is currently based on clinical symptoms and general risk factors. The duration of anticoagulant treatment after an acute episode of PE is still subject to debate and the best method of identifying the risk of recurrence in individual patients is undefined. Tomographic lung scintigraphy [ventilation/perfusion single photon emission computed tomography (V/P SPECT)] has improved the diagnostic accuracy with regard to PE but has not been evaluated for PE follow-up. AIM: The aim of this prospective study was to quantitatively follow the natural history of treated PE using V/P SPECT, which could prove helpful in defining an anticoagulant treatment regime for individual patients. METHODS: Of 83 consecutive patients with clinically suspected PE examined with V/P SPECT, 23 patients with confirmed PE were followed by serial V/P SPECT examinations over a 6-month period. All patients were also followed clinically. RESULTS: The mean relative decrease in PE extent compared with the time of diagnosis was 54±26% at 2 weeks, 79±30% at 3 months, and 82±30% at 6 months. Significant resolution of mismatched perfusion defects occurred between V/P SPECT controls within the first 3 months of anticoagulation (P<0.001) but not thereafter. V/P SPECT identified four patients with chronic PE, even though all patients were free from symptoms at 3-month follow-up. CONCLUSION: Follow-up of PE with V/P SPECT is feasible to evaluate treatment effectiveness in individual patients and to identify patients that develop chronic PE. This study also confirms that resolution of perfusion defects after PE occurs within the first 3 months of treatment. It is therefore recommended that V/P SPECT follow-up should be considered at 3 months after diagnosis.
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| 30. |
- Cheimariotis, Grigorios Aris, et al.
(författare)
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Automatic lung segmentation in functional SPECT images using active shape models trained on reference lung shapes from CT
- 2018
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Ingår i: Annals of Nuclear Medicine. - : Springer Science and Business Media LLC. - 0914-7187 .- 1864-6433. ; 32:2, s. 94-104
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Image segmentation is an essential step in quantifying the extent of reduced or absent lung function. The aim of this study is to develop and validate a new tool for automatic segmentation of lungs in ventilation and perfusion SPECT images and compare automatic and manual SPECT lung segmentations with reference computed tomography (CT) volumes. Methods: A total of 77 subjects (69 patients with obstructive lung disease, and 8 subjects without apparent perfusion of ventilation loss) performed low-dose CT followed by ventilation/perfusion (V/P) SPECT examination in a hybrid gamma camera system. In the training phase, lung shapes from the 57 anatomical low-dose CT images were used to construct two active shape models (right lung and left lung) which were then used for image segmentation. The algorithm was validated in 20 patients, comparing its results to reference delineation of corresponding CT images, and by comparing automatic segmentation to manual delineations in SPECT images. Results: The Dice coefficient between automatic SPECT delineations and manual SPECT delineations were 0.83 ± 0.04% for the right and 0.82 ± 0.05% for the left lung. There was statistically significant difference between reference volumes from CT and automatic delineations for the right (R = 0.53, p = 0.02) and left lung (R = 0.69, p < 0.001) in SPECT. There were similar observations when comparing reference volumes from CT and manual delineations in SPECT images, left lung (bias was − 10 ± 491, R = 0.60, p = 0.005) right lung (bias 36 ± 524 ml, R = 0.62, p = 0.004). Conclusion: Automated segmentation on SPECT images are on par with manual segmentation on SPECT images. Relative large volumetric differences between manual delineations of functional SPECT images and anatomical CT images confirms that lung segmentation of functional SPECT images is a challenging task. The current algorithm is a first step towards automatic quantification of wide range of measurements.
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| 31. |
- Elf, Johan, et al.
(författare)
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Home treatment of patients with small to medium sized acute pulmonary embolism.
- 2015
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Ingår i: Journal of Thrombosis and Thrombolysis. - : Springer Science and Business Media LLC. - 1573-742X .- 0929-5305. ; 39:2, s. 166-172
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Tidskriftsartikel (refereegranskat)abstract
- Most patients with acute pulmonary embolism (PE) are still treated as inpatients. This is a retrospective cohort study of patients with acute PE, diagnosed using V/P SPECT between 2007 and 2011. Patients were treated at home if they were hemodynamically stable, did not require oxygen or parenteral analgetics, had no contraindications to anticoagulant treatment and V/P SPECT showed an extension of the PE of less than 40 %. The aim of the study was to evaluate the efficacy and safety of home treatment with our algorithm. During the study period 416 outpatients were diagnosed with acute symptomatic PE of whom in total 260 (62.5 %) were discharged home from the emergency unit and another 47 (11 %) within 24 h from admission. During 3 months follow-up one (0.3 %) patient had a recurrent thrombotic event. Eleven (3.6 %) patients had a major or clinically relevant bleed and the overall mortality was 2 % (n = 6). There were no PE-related mortality. Home treatment should be considered and is safe in the majority of hemodynamically stable outpatients with small to medium size PE, quantified using V/P SPECT.
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| 32. |
- Grigorios-Aris, Cheimariotis, et al.
(författare)
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Automatic segmentation of lungs in SPECT images using active shape model trained by meshes delineated in CT images
- 2016
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Ingår i: 2016 38th Annual International Conference of the IEEE Engineering in Medicine and Biology Society, EMBC 2016. - 9781457702204 ; 2016-October, s. 1280-1283
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Konferensbidrag (refereegranskat)abstract
- This paper presents a fully automated method for segmentation of 3D SPECT ventilation and perfusion images. It relies on statistical information on lung shape derived by CT manual segmentation and its main processing steps are: shape model extraction, binary segmentation, positioning of mean shape in SPECT images and iterative shape adaptation based on intensity profiles and on what is considered 'plausible' lung shape. The Active Shape Model is used to generate accurate anatomic results in SPECT images with functional information and thus unclear borders, especially in the case of pathologies. The method was compared against ground truth manual segmentation on CT images, using volumetric, difference dice coefficient, sensitivity and precision.
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| 33. |
- Jonson, Björn, et al.
(författare)
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Diagnostics of pulmonary embolism with emphasis of ventilation/perfusion scintigraphy and dead space analysis
- 2006
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Ingår i: Journal of Organ Dysfuntion. - : Informa UK Limited. - 1747-1060 .- 1747-1079. ; 2:4, s. 237-243
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Tidskriftsartikel (refereegranskat)abstract
- Ventilation/perfusion scintigraphy, a first hand method for diagnosis of pulmonary embolism, PE, is challenged by tomography of the pulmonary arteries, CT. An additional method is based upon dead space analysis. Tomographic ventilation/perfusion scintigraphy, V/PSPECT is superior to planar technique. Important is interpretation criteria based upon pattern recognition and clinical information. With optimal strategy, the rate of non-diagnostic findings is only about 1%. The sensitivity of CT is too low to exclude subsegmental PE,. The radiation dose is for CT is several times higher than for V/PSPECT. Quantification of PE, only offered by V/PSPECT has impact on therapy and is vital for follow up. Limited availability of V/PSPECT makes CT an essential element in a strategy for diagnosis of PE. The single breath test for CO2 offers an alternative when imaging techniques are not available or when radiation is a particular problem in early pregnancy.
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| 34. |
- Jögi, Jonas, et al.
(författare)
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Diagnosing and grading heart failure with tomographic perfusion lung scintigraphy : validation with right heart catheterization
- 2018
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Ingår i: ESC Heart Failure. - : Wiley. - 2055-5822. ; 5:5, s. 902-910
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Tidskriftsartikel (refereegranskat)abstract
- Aims: Pulmonary congestion remains a diagnostic challenge in patients with heart failure (HF). The recommended method, chest X-ray (CXR), lacks in accuracy, whereas quantitative tomographic lung scintigraphy [ventilation/perfusion single-photon emission computed tomography (V/P SPECT)] has shown promising results but needs independent validation. The aim of this study is to evaluate V/P SPECT as a non-invasive method to assess and quantify pulmonary congestion in HF patients, using right heart catheterization as reference method. The secondary objective was to investigate the performance of V/P SPECT in the clinical setting compared with CXR. Methods and results: Forty-six consecutive patients with HF that were under consideration for heart transplantation were studied prospectively. All participants were examined with V/P SPECT, CXR, and right heart catheterization. Pulmonary artery wedge pressure served as reference method. Quantitative perfusion gradients were derived from V/P SPECT images. Ventilation/perfusion single-photon emission computed tomography images were also assessed both by expert readers and clinical nuclear medicine physicians. Expert readers correctly identified 87% of all patients with an elevated pulmonary artery wedge pressure > 15 mmHg. The average sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for V/P SPECT assessed by the expert readers were 87%, 72%, 85%, and 75%, respectively. In the clinical nuclear medicine setting, V/P SPECT had 87% sensitivity, 63% specificity, 81% PPV, and 71% NPV. Clinically, V/P SPECT outperformed CXR, which had 27% sensitivity, 75% specificity, 67% PPV, and 35% NPV. Conclusions: Ventilation/perfusion single-photon emission computed tomography can be used as a non-invasive method to diagnose and quantify pulmonary congestion in patients with HF and is more accurate than CXR in diagnosing pulmonary congestion in the clinical setting.
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| 35. |
- Jögi, Jonas, et al.
(författare)
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Heart failure diagnostics based on ventilation/perfusion single photon emission computed tomography pattern and quantitative perfusion gradients.
- 2008
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Ingår i: Nuclear Medicine Communications. - 1473-5628. ; 29:8, s. 666-673
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Left heart failure (LHF) is a common and frequently overlooked condition owing to insufficient diagnostic methods. This can potentially delay onset of treatment. Our clinical experience with ventilation/perfusion single photon emission computed tomography (V/P SPECT) indicates that perfusion shows an antigravitational distribution pattern in LHF. The aim of the study was to test the hypothesis that LHF diagnosis can be made on the basis of V/P SPECT, and to develop and perform a first evaluation of objective parameters for LHF diagnostics in terms of perfusion gradients. METHODS: This retrospective study included 247 consecutive patients with clinical suspicion of pulmonary embolism (PE), who were examined with V/P SPECT. Perfusion gradients were developed and quantified in dorso-ventral and cranio-caudal directions. Quantitative results were compared with visual interpretation of patients with normal and heart failure patterns. Patients with LHF pattern were retrospectively followed up by review of medical records to confirm or discard heart failure diagnosis at the time of V/P SPECT examination. RESULTS: LHF pattern on V/P SPECT was identified in 36 patients (15%), normal ventilation/perfusion pattern was found in 67 patients (27%), and PE in 62 patients (25%). The follow-up confirmed heart failure diagnosis in 32 of the 36 cases with LHF pattern, leading to a positive predictive value of 88% for LHF diagnosis based on V/P SPECT. Dorso-ventral perfusion gradients discriminated normal from LHF patients. CONCLUSION: In patients with suspected PE, LHF is common. Appropriate V/P SPECT pattern recognition, supported by objectively determined dorso-ventral perfusion gradients, allows the diagnosis of LHF. A positive perfusion gradient in the dorso-ventral direction should lead to consideration of heart failure as a possible explanation for the symptoms in these patients.
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| 36. |
- Jögi, Jonas, et al.
(författare)
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The added value of hybrid ventilation/perfusion SPECT/CT in patients with stable COPD or apparently healthy smokers. Cancer-suspected CT findings in the lungs are common when hybrid imaging is used
- 2015
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Ingår i: The International Journal of Chronic Obstructive Pulmonary Disease. - 1178-2005. ; 10, s. 25-30
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Tidskriftsartikel (refereegranskat)abstract
- Ventilation/perfusion (V/P) single-photon emission computed tomography (SPECT) is recognized as a diagnostic method with potential beyond the diagnosis of pulmonary embolism. V/P SPECT identifies functional impairment in diseases such as heart failure (HF), pneumonia, and chronic obstructive pulmonary disease (COPD). The development of hybrid SPECT/computed tomography (CT) systems, combining functional with morphological imaging through the addition of low-dose CT (LDCT), may be useful in COPD, as these patients are prone to lung cancer and other comorbidities. The aim of this study was to investigate the added value of LDCT among healthy smokers and patients with stable COPD, when examined with V/P SPECT/CT hybrid imaging. Sixty-nine subjects, 55 with COPD (GOLD I-IV) and 14 apparently healthy smokers, were examined with V/P SPECT and LDCT hybrid imaging. Spirometry was used to verify COPD grade. Only one apparently healthy smoker and three COPD patients had a normal or nearly normal V/P SPECT. All other patients showed various degrees of airway obstruction, even when spirometry was normal. The same interpretation was reached on both modalities in 39% of the patients. LDCT made V/P SPECT interpretation more certain in 9% of the patients and, in 52%, LDCT provided additional diagnoses. LDCT better characterized the type of emphysema in 12 patients. In 19 cases, tumor-suspected changes were reported. Three of these 19 patients (ie, 4.3% of all subjects) were in the end confirmed to have lung cancer. The majority of LDCT findings were not regarded as clinically significant. V/P SPECT identified perfusion patterns consistent with decompensated left ventricular HF in 14 COPD patients. In 16 patients (23%), perfusion defects were observed. HF and perfusion defects were not recognized with LDCT. In COPD patients and long-time smokers, hybrid imaging had added value compared to V/P SPECT alone, by identifying patients with lung malignancy and more clearly identifying emphysema. V/P SPECT visualizes comorbidities to COPD not seen with LDCT, such as pulmonary embolism and left ventricular HF.
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| 37. |
- Jögi, Jonas, et al.
(författare)
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Ventilation/perfusion SPECT in chronic obstructive pulmonary disease: an evaluation by reference to symptoms, spirometric lung function and emphysema, as assessed with HRCT.
- 2011
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 38, s. 1344-1352
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Chronic obstructive pulmonary disease (COPD) is characterized by airflow limitation which is not fully reversible. Despite the heterogeneity of COPD, its diagnosis and staging is currently based solely on forced expiratory volume in 1 s (FEV(1)). FEV(1) does not explain the underlying pathophysiology of airflow limitation. The relationship between FEV(1), symptoms and emphysema extent is weak. Better diagnostic tools are needed to define COPD. Tomographic lung scintigraphy [ventilation/perfusion single photon emission tomography (V/P SPECT)] visualizes regional V and P. In COPD, relations between V/P SPECT, spirometry, high-resolution computed tomography (HRCT) and symptoms have been insufficiently studied. The aim of this study was to investigate how lung function imaging and obstructive disease grading undertaken using V/P SPECT correlate with symptoms, spirometric lung function and degree of emphysema assessed with HRCT in patients with COPD. METHODS: Thirty patients with stable COPD were evaluated with the Medical Research Council dyspnoea questionnaire (MRC) and the clinical COPD questionnaire (CCQ). Spirometry was performed. The extent of emphysema was assessed using HRCT. V/P SPECT was used to assess V/P patterns, total reduction in lung function and degree of obstructive disease. RESULTS: The total reduction in lung function and degree of obstructive disease, assessed with V/P SPECT, significantly correlated with emphysema extent (r = 0.66-0.69, p < 0.0001) and spirometric lung function (r = 0.62-0.74, p < 0.0005). The correlation between emphysema extent and spirometric lung function was weaker. No correlation between MRC, CCQ and objective measurements was found. CONCLUSION: V/P SPECT is sensitive to early changes in COPD. V/P SPECT also has the possibility to identify comorbid disease. V/P SPECT findings show a significant correlation with emphysema extent and spirometric lung function. We therefore recommend that scintigraphic signs of COPD, whenever found, should be reported. V/P SPECT can also be used to categorize the severity of functional changes in COPD as mild, moderate or severe.
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| 38. |
- Jögi, Jonas, et al.
(författare)
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Ventilation-Perfusion SPECT with Tc-99m-DTPA Versus Technegas: A Head-to-Head Study in Obstructive and Nonobstructive Disease
- 2010
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Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 2159-662X. ; 51:5, s. 735-741
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Tidskriftsartikel (refereegranskat)abstract
- Lung scintigraphy is primarily used to diagnose pulmonary embolism. Ventilation imaging is often performed using Tc-99m-DTPA or Technegas, an ultrafine dispersion of Tc-99m-labeled carbon. Despite the common use of these radioaerosols, they have not been compared in an intraindividual study, and not with ventilation-perfusion (V/P) SPECT. The aim of the present head-to-head study was to systematically investigate differences in ventilation studies performed with Tc-99m-diethylenetriaminepentaacetate (DTPA) and Technegas. Methods: Sixty-three patients, 28 without and 35 with obstructive lung disease, were examined with V/P SPECT using both Tc-99m-DTPA and Technegas. V/P SPECT images were randomized and assessed independently by 2 masked physicians according to a predefined scoring system. A paired comparison was performed using the Wilcoxon signed-rank test. Results: In both obstructive and nonobstructive disease, the overall unevenness of radiotracer deposition and the degree of central deposition were more pronounced in Tc-99m-DTPA than Technegas studies. Because of better peripheral penetration, the extent of reverse mismatch was less when Technegas was used. Additionally, in obstructive disease, the degree of focal deposition in distal airways was more pronounced with Tc-99m-DTPA. Mismatched perfusion defects were more frequently found with Technegas in obstructive disease. Conclusion: This intraindividual comparative study shows that Technegas is the preferred radioaerosol, particularly in obstructive disease.
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| 39. |
- Keussen, Inger, et al.
(författare)
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Changes in the distribution of hepatic arterial blood flow following TIPS with uncovered stent and stent-graft: An experimental study
- 2002
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Ingår i: Cardiovascular and Interventional Radiology. - : Springer Science and Business Media LLC. - 1432-086X .- 0174-1551. ; 25:4, s. 314-317
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To evaluate changes in distribution of hepatic arterial blood flow in the liver following insertion of an uncovered stent and subsequently a stent-graft in the trans-jugular intrahepatic portosystemic shunt (TIPS) channel. Methods: The experiments were performed in eight healthy pigs under general anesthesia. In a pilot study in one pig, scintigraphic evaluation of arterial perfusion to the liver was done before and after inflation of a balloon in the right hepatic vein. In the other pigs, outflow from the right liver vein was checked repeatedly by contrast injection through a percutaneously inserted catheter. The arterial perfusion through the liver was examined by scintigraphy, following selective injection of macro-aggregate of Tc-99(m)-labeled human serum albumin Tc-99(m)-HSA) into the hepatic artery. This examination was done before and after creation of a TIPS with an uncovered stent and subsequently after insertion of a covered stent-graft into the cranial portion of the shunt channel. Results: In the pilot study changes in the arterial perfusion to the liver were easily detectable by scintigraphy. One pig died during the procedure and another pig was excluded due to dislodgement of the hepatic artery catheter. The inserted covered stent obstructed venous outflow from part of the right liver lobe. The Tc-99(m)-HSA activity in this part remained unchanged after TIPS creation with an uncovered stent. A reduction in activity was seen after insertion of a stent-graft (p = 0.06). Conclusion: The distribution of the hepatic arterial blood flow is affected by creation of a TIPS with a stent-graft, in the experimental pig model.
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| 40. |
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| 41. |
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| 42. |
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| 43. |
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| 44. |
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| 45. |
- Palmer, John, et al.
(författare)
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Comprehensive ventilation/perfusion SPECT
- 2001
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Ingår i: Journal of Nuclear Medicine. - 0161-5505. ; 42:8, s. 1288-1294
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Tidskriftsartikel (refereegranskat)abstract
- Lung scintigraphy is the primary tool for diagnostics of pulmonary embolism. A perfusion study is often complemented by a ventilation study. Intermediate probability scans are frequent. Our goal was to develop a fast method for tomographic ventilation and perfusion scintigraphy to improve the diagnostic value of lung scintigraphy. METHODS: SPECT was performed with a dual-head gamma camera. Acquisition parameters were determined using a thorax phantom. Ventilation tomography after inhalation of 30 MBq (99m)Tc-diethylenetriaminepentaacetate (DTPA) aerosol was, without patient movement, followed by perfusion tomography after an intravenous injection of 100 MBq (99m)Tc-labeled macroaggregated albumin (MAA). Total SPECT acquisition time was 20 min. (99m)Tc-DTPA clearance, calculated from initial and final SPECT projections, was used for correction of the ventilation projection set before iterative reconstruction of ventilation and perfusion. The ventilation background was subtracted from the perfusion tomograms. A normalized ventilation/perfusion quotient (V/P quotient) image set was calculated. The method was evaluated on a trial group of 15 patients. RESULTS: Ventilation and perfusion images had adequate quality and showed ventilation/perfusion (V/Q quotient) relationships more clearly than did planar images. Frontal and sagittal slices were superior to planar scintigraphy for characterization of embolized areas. The V/Q quotient was supportive, particularly in the patients with chronic obstructive pulmonary disease. CONCLUSION: Fast, high-quality, ventilation/perfusion SPECT with standard isotopes doses is feasible and may contribute to higher objectivity in evaluating lung embolism as well as other lung diseases. The costs for the procedure and patient care until diagnosis are low because of the comprehensive system for the study and, particularly, the short time for its completion.
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| 46. |
- Poropat, M, et al.
(författare)
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Lung examinations
- 2005
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Ingår i: Nuklearna kardiologija i pulmologija (Nuclear cardiology and pulmology). - 9531762953 ; , s. 105-105
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Bokkapitel (refereegranskat)
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| 47. |
- Roach, Paul J., et al.
(författare)
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Acute Pulmonary Embolism
- 2010
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Ingår i: New England Journal of Medicine. - 0028-4793. ; 363:20, s. 1972-1973
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 48. |
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| 49. |
- Stein, Paul D., et al.
(författare)
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Controversies in Diagnosis of Pulmonary Embolism
- 2011
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Ingår i: Clinical and Applied Thrombosis/Hemostasis. - : SAGE Publications. - 1938-2723 .- 1076-0296. ; 17:2, s. 140-149
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Tidskriftsartikel (refereegranskat)abstract
- The approach to the diagnosis of acute pulmonary embolism (PE) is under constant revision with advances in technology, noninvasive approaches, and increasing awareness of the risks of ionizing radiation. Optimal approaches in some categories of patients are controversial. Data are insufficient for evidence-based recommendations. Therefore, this survey of investigators in the field was undertaken. Even among experts there were marked differences of opinion regarding the approach to the diagnosis of acute PE. Although CT pulmonary angiography was usually the imaging test of choice, the respondents were keenly aware of the dangers of ionizing radiation. In view of advances in scintigraphic diagnosis since the Prospective Investigation of Pulmonary Embolism Diagnosis (PIOPED) trial, ventilation/perfusion (V/Q) lung scans or perfusion scans alone and single photon emission computed tomography (SPECT) V/Q lung scans are often recommended. The choice depends on the patient's age, gender, and complexity of the findings on the plain chest radiograph.
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| 50. |
- Wallin, Lena, et al.
(författare)
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Follow-up of acute pyelonephritis in children by Tc-99m DMSA scintigraphy - Quantitative and qualitative assessment
- 2001
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Ingår i: Clinical Nuclear Medicine. - 0363-9762. ; 26:5, s. 423-432
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: The author's goal was to create a system to identify children at risk for development of progressive renal damage, Methods: Thirty-four children were examined with Tc-99m DMSA scintigraphy in the acute stage of an initial episode of pyelonephritis, after 6 months, and again after 1 year, The scintigraphic findings were correlated with clinical and laboratory data, Results: All children had parenchymal defects in the acute stage: 93% of the kidneys and 85% bilaterally, After 6 months, the defects had diminished or disappeared in 66% of the kidneys, New defects appeared in 22%, At 1 year, no further improvement was seen in the kidneys, with an improved or unchanged pattern at 6 months, New defects appeared in 34%, Mean kidney activity uptake expressed as the percentage of administered dose (KU/AD), was low in the acute stage, increased at 6 months, with no further significant increase at 1 year, Eighty-three percent of children with urine cultures growing greater than or equal to 10(4) bacteria/ml at follow-up had decreased KU/AD values, whereas all children with urine cultures growing < 10(4) bacteria/ml had increased KU/AD values. Conclusions: Quantitative assessment increases the sensitivity of Tc-99m DMSA scintigraphy. Follow-up with this method makes it possible to identify the children with decreasing renal tubular function who may be at risk for progressive renal damage, Moderate bacteria of 104 bacteria/ml urine is associated with deterioration of renal tubular function.
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