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  • Brismar, Torkel, et al. (författare)
  • Liver Vessel Enhancement by Gd-BOPTA and Gc-EOB-DTPA – a Comparison in Healthy Volunteers.
  • 2009
  • Ingår i: Acta Radiologica. - Informa Healthcare. - 0284-1851. ; 50:7, s. 709-715
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: A thorough understanding of magnetic resonance (MR) contrast media dynamics makes it possible to choose the optimal contrast media for each investigation. Differences in visualizing hepatobiliary function between Gd-BOPTA and Gd-EOB-DTPA have previously been demonstrated, but less has been published regarding differences in liver vessel visualization.Purpose: To compare the liver vessel and liver parenchymal enhancement dynamics of Gd-BOPTA (MultiHance®) and Gd-EOB-DTPA (Primovist®). Material and Methods: The signal intensity of the liver parenchyma, the common hepatic artery, the middle hepatic vein, and a segmental branch of the right portal vein, was obtained in 10 healthy volunteers before contrast media administration, during arterial and portal venous phases, and 10, 20, 30, 40 and 130 minutes after intravenous contrast medium injection, but due to scanner limitations not during the hepatic venous phase. Results: Maximum enhancement of liver parenchyma was observed from the portal venous phase until 130 minutes after Gd-BOPTA administration and from 10 minutes to 40 minutes after Gd-EOB-DTPA. There was no difference in maximum enhancement of liver parenchyma between the two contrast media. When using Gd-BOPTA, the vascular contrast enhancement was still apparent 40 minutes after injection, but had vanished 10 minutes after Gd-EOB-DTPA injection. The maximum difference in signal intensity between the vessels and the liver parenchyma was significantly greater with Gd-BOPTA than with Gd-EOB-DTPA (p<0.0001). Conclusion: At the dosage used in this study Gd-BOPTA yields higher maximum enhancement of the hepatic artery, portal vein and middle hepatic vein during the arterial and the portal venous phase and during the delayed phases than Gd-EOB-DTPA does, whereas there is no difference in liver parenchymal enhancement between the two contrast agents.
  • Brismar, Torkel, et al. (författare)
  • Three-dimensional drip infusion CT cholangiography in patients with suspected obstructive biliary disease : a retrospective analysis of feasibility and adverse reaction to contrast material
  • 2006
  • Ingår i: BMC Medical Imaging. - 1471-2342. ; 6:1
  • Tidskriftsartikel (refereegranskat)abstract
    • BackgroundComputed Tomography Cholangiography (CTC) is a fast and widely available alternative technique to visualise hepatobiliary disease in patients with an inconclusive ultrasound when MRI cannot be performed. The method has previously been relatively unknown and sparsely used, due to concerns about adverse reactions and about image quality in patients with impaired hepatic function and thus reduced contrast excretion. In this retrospective study, the feasibility and the frequency of adverse reactions of CTC when using a drip infusion scheme based on bilirubin levels were evaluated.MethodsThe medical records of patients who had undergone upper abdominal spiral CT with subsequent three-dimensional rendering of the biliary tract by means of CTC during seven years were retrospectively reviewed regarding serum bilirubin concentration, adverse reaction and presence of visible contrast media in the bile ducts at CT examination. In total, 153 consecutive examinations in 142 patients were reviewed.ResultsContrast media was observed in the bile ducts at 144 examinations. In 110 examinations, the infusion time had been recorded in the medical records. Among these, 42 examinations had an elevated bilirubin value (>19 umol/L). There were nine patients without contrast excretion; 3 of which had a normal bilirubin value and 6 had an elevated value (25–133 umol/L). Two of the 153 examinations were inconclusive. One subject (0.7%) experienced a minor adverse reaction – a pricking sensation in the face. No other adverse effects were noted.ConclusionWe conclude that drip infusion CTC with an infusion rate of the biliary contrast agent iotroxate governed by the serum bilirubin value is a feasible and safe alternative to MRC in patients with and without impaired biliary excretion.In this retrospective study the feasibility and the frequency of adverse reactions when using a drip infusion scheme based on bilirubin levels has been evaluated.
  • Brismar, Torkel, et al. (författare)
  • Volume rendering of three-dimensional drip infusion CT cholangiography in patients with suspected obstructive biliary disease : a retrospective study
  • 2005
  • Ingår i: British Journal of Radiology. - 0007-1285. ; 78:936, s. 1078-1085
  • Tidskriftsartikel (refereegranskat)abstract
    • The purpose of this study was to evaluate the diagnostic potential of prolonged drip infusion CT cholangiography (DIC-CT) using meglumine iotroxate (Biliscopin®) and 3D volume rendering in patients with suspected obstructive biliary disease. From a material of 142 patients who had undergone a drip infusion CT, all cases with a verified surgical or endoscopic retrograde cholangiography (ERC) diagnosis (n=33) were selected. Age-matched controls were selected from the remaining examinations. Three radiologists reviewed all 66 examinations in retrospect, independently as well as in consensus. The image quality and the estimated diagnostic quality were rated as good or moderate in 91% of the 198 reviews. The consensus sensitivity and specificity for diagnosing biliary stones was 88% and 94%, respectively (with sensitivities ranging from 88% to 94% for individual observers, and specificities from 86% to 96%). Two out of three strictures were observed. No false positive strictures were described. The use of volume rendering technique (VRT) improved diagnostic certainty in 28/198 (14%) of the evaluations. The visualization of ductal stones was improved in 18/48 (38%). No differences in diagnostic quality between single and multislice CT were observed. We conclude that a detailed image of the biliary tree with good sensitivity and specificity can be obtained by means of bilirubin-governed infusion time DIC-CT with volume rendering reconstruction.
  • Dahlström, Nils, 1969-, et al. (författare)
  • Contrast-enhanced magnetic resonance cholangiography with Gd-BOPTA and Gd-EOB-DTPA in healthy subjects
  • 2007
  • Ingår i: Acta Radiologica. - Informa Healthcare. - 0284-1851. ; 48:4, s. 362-368
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: To evaluate the biliary enhancement dynamics of the two gadolinium chelates Gd-BOPTA (MultiHance) and Gd-EOB-DTPA (Primovist) in normal healthy subjects. MATERIAL AND METHODS: Ten healthy volunteers were evaluated with both agents by magnetic resonance (MR) imaging at 1.5T using a breath-hold gradient-echo T1-weighted VIBE sequence. The relative signal intensity (SI) differences between the common hepatic duct (CHD) and liver parenchyma were measured before and 10, 20, 30, 40, 130, 240, and 300 min after contrast medium injection. RESULTS: Biliary enhancement was obvious 10 min post-injection for Gd-EOB-DTPA and was noted at 20 min for Gd-BOPTA. At 40 min delay, Gd-BOPTA reached its peak biliary enhancement, but at neither 30 nor 40 min delay was there any significant difference compared with that of Gd-EOB-DTPA. At later delays, the contrast between CHD and liver continued to increase for Gd-EOB-DTPA, whereas it decreased for Gd-BOPTA. CONCLUSION: The earlier onset and longer duration of a high contrast between CHD and liver for Gd-EOB-DTPA facilitates examination of hepatobiliary excretion. Therefore, Gd-EOB-DTPA may provide adequate hepatobiliary imaging within a shorter time span than Gd-BOPTA and facilitate scheduling at the MR unit. Further studies in patients are required to compare the imaging advantages of Gd-EOB-DTPA and Gd-BOPTA in clinical practice.
  • de Geer, Jakob, et al. (författare)
  • The efficacy of 2D, non-linear noise reduction filtering in cardiac imaging: a pilot study
  • 2011
  • Ingår i: Acta Radiologica. - Informa Healthcare / Wiley-Blackwell / Royal Society of Medicine Press. - 0284-1851. ; 52:7, s. 716-722
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Computed tomography (CT) is becoming increasingly popular as a non-invasive method for visualizing the coronary arteries but patient radiation doses are still an issue. Postprocessing filters such as 2D adaptive non-linear filters might help to reduce the dose without loss of image quality. less thanbrgreater than less thanbrgreater thanPurpose: To investigate whether the use of a 2D, non-linear adaptive noise reduction filter can improve image quality in cardiac computed tomography angiography (CCTA). less thanbrgreater than less thanbrgreater thanMaterial and Methods: CCTA examinations were performed in 36 clinical patients on a dual source CT using two patient dose levels: maximum dose during diastole and reduced dose (20% of maximum dose) during systole. One full-dose and one reduced-dose image were selected from each of the examinations. The reduced-dose image was duplicated and one copy postprocessed using a 2D non-linear adaptive noise reduction filter, resulting in three images per patient. Image quality was assessed using visual grading with three criteria from the European guidelines for assessment of image quality and two additional criteria regarding the left main artery and the overall image quality. Also, the HU value and its standard deviation were measured in the ascending and descending aorta. Data were analyzed using Visual Grading Regression and paired t-test. less thanbrgreater than less thanbrgreater thanResult: For all five criteria, there was a significant (P andlt; 0.01 or better) improvement in perceived image quality when comparing postprocessed low-dose images with low-dose images without noise reduction. Comparing full dose images with postprocessed low-dose images resulted in a considerably larger, significant (P andlt; 0.001) difference. Also, there was a significant reduction of the standard deviation of the HU values in the ascending and descending aorta when comparing postprocessed low-dose images with low-dose images without postprocessing. less thanbrgreater than less thanbrgreater thanConclusion: Even with an 80% dose reduction, there was a significant improvement in the perceived image quality when using a 2D noise-reduction filter, though not approaching the quality of full-dose images. This indicates that cardiac CT examinations could benefit from noise-reducing postprocessing with 2D non-linear adaptive filters.
  • Eriksson, Per, et al. (författare)
  • Non-invasive investigations of potential renal artery stenosis in renal insufficiency
  • 2010
  • Ingår i: Nephrology, Dialysis and Transplantation. - Oxford University Press. - 0931-0509. ; 25:11, s. 3607-3614
  • Tidskriftsartikel (refereegranskat)abstract
    • Background. The diagnostic value of non-invasive methods for diagnosing renal artery stenosis in patients with renal insufficiency is incompletely known. Methods. Forty-seven consecutive patients with moderately impaired renal function and a clinical suspicion of renal artery stenosis were investigated with computed tomography angiography (CTA), gadolinium-enhanced magnetic resonance angiography (MRA), contrast-enhanced Doppler ultrasound and captopril renography. The primary reference standard was stenosis reducing the vessel diameter by at least 50% on CTA, and an alternative reference standard (‘morphological and functional stenosis’) was defined as at least 50% diameter reduction on CTA or MRA, combined with a positive finding from ultrasound or captopril renography. Results. The frequency of positive findings, calculated on the basis of individual patients, was 70% for CTA, 60% for MRA, 53% for ultrasound and 30% for captopril renography. Counting kidneys rather than patients, corresponding frequencies were 53%, 41%, 29% and 15%, respectively. In relation to the CTA standard, the sensitivity (and specificity) at the patient level was 0.81 (0.79) for MRA, 0.70 (0.89) for ultrasound and 0.42 (1.00) for captopril renography, and at the kidney level 0.76 (0.82), 0.53 (0.81) and 0.30 (0.86), respectively. Relative to the alternative reference standard, corresponding values at the patient level were 1.00 (0.62) for CTA, 0.90 (0.69) for MRA, 0.91 (1.00) for ultrasound and 0.67 (1.00) for captopril renography, and at the kidney level 0.96 (0.76), 0.85 (0.79), 0.71 (0.97) and 0.50 (0.97), respectively. Conclusions. CTA and MRA are superior to ultrasound and captopril renography at diagnosing morphological stenosis, but ultrasound may be useful as a screening method and captopril renography for verifying renin-dependent hypertension.
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