| 1. |
- Björkengren, Ann G, et al.
(författare)
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MR imaging of the knee in acute rheumatoid arthritis: synovial uptake of gadolinium-DOTA
- 1990
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Ingår i: American Journal of Roentgenology: diagnostic imaging and related sciences. - 1546-3141. ; 155:2, s. 329-332
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Tidskriftsartikel (refereegranskat)abstract
- In patients with rheumatoid arthritis, the presence of acute synovial inflammation is an indication of the activity of the disease. It is an important finding because it often influences therapeutic decisions. However, acute synovitis may be difficult to detect by clinical examination, especially if a joint effusion also is present. As gadolinium tetra-azacyclododecane tetraacetic acid (Gd-DOTA) can be expected to accumulate in areas of acute inflammation, we studied the value of Gd-DOTA-enhanced MR to determine the presence of acute synovitis. Nine patients with current knee symptoms underwent MR examination of the knee. Short and long TR/TE MR images were obtained with a 0.3-T magnet before and immediately after IV administration of Gd-DOTA. A 15-min delayed short TR/TE image also was obtained. Of eight patients with moderate to severe clinical evidence of acute synovitis, six had marked increase and two had moderate increase in signal intensity from synovial tissue on the short TR/TE image obtained immediately after administration of contrast material. In the ninth patient, who had minimal synovitis clinically, the signal from the synovium did not change after administration of contrast material. No difference was seen between the enhancement pattern on the immediate and the 15-min delayed images. These results suggest that Gd-DOTA is taken up by inflamed synovium and that Gd-DOTA-enhanced MR scans may be useful in detecting acute synovitis in patients with rheumatoid arthritis.
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| 2. |
- Blomqvist, L
(författare)
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Colorectal cancer imaging
- 2004
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Ingår i: AJR. American journal of roentgenology. - : American Roentgen Ray Society. - 0361-803X .- 1546-3141. ; 182:6, s. 1600-1601
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 3. |
- Dahlman, Pär, et al.
(författare)
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How Much Dose Can Be Saved in Three-Phase CT Urography? A Combination of Normal-Dose Corticomedullary Phase With Low-Dose Unenhanced and Excretory Phases
- 2012
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Ingår i: American Journal of Roentgenology. - 0361-803X .- 1546-3141. ; 199:4, s. 852-860
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE:The purpose of this study was to investigate the degree to which the total radiation dose for CT urography can be lowered by selective reduction of the dose in the unenhanced and excretory phases when images in these phases are systematically evaluated alongside normal-dose corticomedullary phase images.SUBJECTS AND METHODS:Twenty-seven patients (mean age, 74 ± 9 years) underwent single-bolus CT urography with acquisition in the unenhanced, corticomedullary, and 5-minute excretory phases. The scanning parameters for normal-dose CT urography were as follows: 16 × 0.75 mm, 120 kV, and automatic exposure control technique reference tube loads of 100, 120, and 100 effective mAs (mAseff). The patients also underwent low-dose unenhanced and excretory phase scanning, in which the dose was escalated stepwise from a volume CT dose index (CTDIvol) of 1.7 to 6.6 mGy (reference 20-40-60-80 mAseff). Images were analyzed for quality and diagnostic confidence. If low-dose scans of three patients were inadequate, the study continued to the next dose level. When 20 patients were successfully included in the unenhanced and excretory phase groups, the study ended. Doses were calculated with a CT patient dosimetry calculator.RESULTS:Combined with the normal dose for corticomedullary phase scanning, doses of CTDIvol 1.5 mGy for the unenhanced phase and CTDIvol 2.7 mGy for the excretory phase were sufficient. The effective dose for three-phase CT urography was lowered from 16.2 to 9.4 mSv, a decrease of 42%. Diagnostic confidence in low-dose images was equal to that in normal-dose images when low-dose unenhanced and excretory phase images were read along-side normal-dose corticomedullary phase images.CONCLUSION:With a three-phase CT urographic protocol, significant dose reductions in the unenhanced and excretory phases can be achieved when these phases are combined with a normal-dose corticomedullary phase.
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| 4. |
- de Geer, Jakob, et al.
(författare)
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Effect of Tube Voltage on Diagnostic Performance of Fractional Flow Reserve Derived From Coronary CT Angiography With Machine Learning: Results From the MACHINE Registry
- 2019
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Ingår i: American Journal of Roentgenology. - : AMER ROENTGEN RAY SOC. - 0361-803X .- 1546-3141. ; 213:2, s. 325-331
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE. Coronary CT angiography (CCTA)-based methods allow noninvasive estimation of fractional flow reserve (cFFR), recently through use of a machine learning (ML) algorithm (cFFR(ML)). However, attenuation values vary according to the tube voltage used, and it has not been shown whether this significantly affects the diagnostic performance of cFFR and cFFR(ML). Therefore, the purpose of this study is to retrospectively evaluate the effect of tube voltage on the diagnostic performance of cFFR(ML). MATERIALS AND METHODS. A total of 525 coronary vessels in 351 patients identified in the MACHINE consortium registry were evaluated in terms of invasively measured FFR and cFFR(ML). CCTA examinations were performed with a tube voltage of 80, 100, or 120 kVp. For each tube voltage value, correlation (assessed by Spearman rank correlation coefficient), agreement (evaluated by intraclass correlation coefficient and Bland-Altman plot analysis), and diagnostic performance (based on ROC AUC value, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy) of the cFFR(ML) in terms of detection of significant stenosis were calculated. RESULTS. For tube voltages of 80, 100, and 120 kVp, the Spearman correlation coefficient for cFFR(ML) in relation to the invasively measured FFR value was rho = 0.684, rho = 0.622, and rho = 0.669, respectively (p amp;lt; 0.001 for all). The corresponding intraclass correlation coefficient was 0.78, 0.76, and 0.77, respectively (p amp;lt; 0.001 for all). Sensitivity was 100.0%, 73.5%, and 85.0%, and specificity was 76.2%, 79.0%, and 72.8% for tube voltages of 80, 100, and 120 kVp, respectively. The ROC AUC value was 0.90, 0.82, and 0.80 for 80, 100, and 120 kVp, respectively (p amp;lt; 0.001 for all). CONCLUSION. CCTA-derived cFFR(ML) is a robust method, and its performance does not vary significantly between examinations performed using tube voltages of 100 kVp and 120 kVp. However, because of rapid advancements in CT and postprocessing technology, further research is needed.
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| 5. |
- Ekberg, Olle, et al.
(författare)
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Altered swallowing function in elderly patients without dysphagia: radiologic findings in 56 cases
- 1991
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Ingår i: American Journal of Roentgenology: diagnostic imaging and related sciences. - 1546-3141. ; 156:6, s. 1181-1184
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Tidskriftsartikel (refereegranskat)abstract
- Swallowing disorder is an increasing problem in our aging population. A majority of these patients have a functional abnormality of the oral, pharyngeal, and/or esophageal stage of swallowing. However, what constitutes normalcy is not well understood, and baseline swallowing in elderly persons without dysphagia has not been adequately described. We therefore evaluated 56 persons with a mean age of 83 years who had no symptoms of dysphagia or eating difficulty. Videofluoroscopy and radiographs with the subject erect and recumbent were obtained. Normal deglutition, as defined in young persons, was present in only 16%. Oral abnormalities (difficulty ingesting, controlling, and delivering bolus relative to swallowing initiation) were seen in 63%. Pharyngeal dysfunction (bolus retention and lingual propulsion or pharyngeal constrictor paresis) was seen in 25%. Pharyngoesophageal segment abnormalities were observed in 39% (mostly cricopharyngeal muscle dysfunction). Esophageal abnormalities (mostly motor in nature) were observed in 36%. What has been described as swallowing dysfunction in young persons may not be abnormal in very elderly persons. It is difficult to distinguish the effect of normal aging from the effects of specific diseases or gradual degenerative changes.
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| 6. |
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| 7. |
- Feinberg, Michael J, et al.
(författare)
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Videofluoroscopy in elderly patients with aspiration: importance of evaluating both oral and pharyngeal stages of deglutition
- 1991
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Ingår i: American Journal of Roentgenology: diagnostic imaging and related sciences. - 1546-3141. ; 156:2, s. 293-296
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Tidskriftsartikel (refereegranskat)abstract
- Oropharyngeal functional impairment increases with age so that radiologists frequently are asked to determine the cause of aspiration in elderly patients. Neuromuscular and cognitive impairment often make it difficult to perform and interpret videofluoroscopic deglutition examinations in these patients. We retrospectively reviewed the barium swallow examinations in 50 elderly patients (mean age, 87 years) who were known to aspirate. We looked for specific patterns of oropharyngeal dysfunction that resulted in bolus misdirection. Analysis revealed that aspiration was due to abnormalities of the oral stage in 23, pharyngeal stage in 10, and both stages in 17. Dysfunction in the oral stage was due to ingestion of large volumes or rapid acquisition rates in nine, failure of containment during processing (bolus manipulation) in 18, and dissociation of lingual delivery and swallowing initiation in the transitional phase in 13. Dysfunction in the pharyngeal stage was due to incomplete transport (bolus retention) in 21 and defective closure of the laryngeal vestibule in 11. No significant relationship between conditions known to cause oropharyngeal dysfunction (dementia, stroke, Parkinson disease, disuse deconditioning) and the specific pattern of dysfunction was identified. These results indicate that an accurate and valid assessment of oropharyngeal dysfunction in elderly patients with aspiration is possible if specific patterns of dysfunction are sought. Our study indicates the importance of evaluating the oral and pharyngeal stages of deglutition in elderly patients who aspirate.
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| 8. |
- Fält, Tobias, et al.
(författare)
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Seesaw Balancing Radiation Dose and IV Contrast Dose: Evaluation of a New Abdominal CT Protocol for Reducing Age-Specific Risk.
- 2013
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Ingår i: American Journal of Roentgenology: diagnostic imaging and related sciences. - 1546-3141. ; 200:2, s. 383-388
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Tidskriftsartikel (refereegranskat)abstract
- The purpose of this study was to evaluate an abdominal CT protocol in which radiation dose was reduced and IV contrast dose increased for young patients and radiation dose was increased and IV medium dose decreased for elderly patients. The hypothesis was that these adjustments would result in constant image quality and a reduction in age-specific risk.
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| 9. |
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| 10. |
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| 11. |
- Hu, Leland S, et al.
(författare)
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Advanced Imaging in the Diagnosis and Response Assessment of High-Grade Glioma : AJR Expert Panel Narrative Review.
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Ingår i: American Journal of Roentgenology: diagnostic imaging and related sciences. - 1546-3141.
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Forskningsöversikt (refereegranskat)abstract
- This AJR Expert Panel Narrative explores the current status of advanced MRI and PET techniques for the post-therapeutic response assessment of high-grade adult-type gliomas, focusing on ongoing clinical controversies in current practice. Discussed techniques that complement conventional MRI and aid the differentiation of recurrent tumor from post-treatment effects include DWI and diffusion tensor imaging; perfusion MRI techniques including dynamic susceptibility contrast (DSC), dynamic contrast-enhanced MRI, and arterial spin labeling; MR spectroscopy including assessment of 2-hydroxyglutarate (2HG) concentration; glucose- and amino acid (AA)-based PET; and amide proton transfer imaging. Updated criteria for Response Assessment in Neuro-Oncology are presented. Given the abundant supporting clinical evidence, the panel supports a recommendation that routine response assessment after HGG treatment should include perfusion MRI, particularly given the development of a consensus recommended DSC-MRI protocol. Although published studies support 2HG MRS and AA PET, these techniques' widespread adoption will likely require increased availability (for 2HG MRS) or increased insurance funding in the United States (for AA PET). The article concludes with a series of consensus opinions from the author panel, centered on the clinical integration of the advanced imaging techniques into posttreatment surveillance protocols.
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| 12. |
- Kalra, Mannudeep K., et al.
(författare)
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Sinogram-Affirmed Iterative Reconstruction of Low-Dose Chest CT: Effect on Image Quality and Radiation Dose
- 2013
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Ingår i: American Journal of Roentgenology. - : American Roentgen Ray Society (ARRS). - 0361-803X .- 1546-3141. ; 201:2, s. W235-W244
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE. The purpose of this study is to compare sinogram-affirmed iterative reconstruction (SAFIRE) and filtered back projection (FBP) reconstruction of chest CT acquired with 65% radiation dose reduction.SUBJECTS AND METHODS. In this prospective study involving 24 patients (11 women and 13 men; mean [+/- SD] age, 66 +/- 10 years), two scan series were acquired using 100 and 40 Quality Reference mAs over a 10-cm scan length in the chest with a 128-MDCT scanner. The 40 Quality Reference mAs CT projection data were reconstructed with FBP and four settings of Safire (S1, S2, S3, and S4). Six image datasets (FBP with 100 and 40 Quality Reference mAs, and S1, S2, S3, S4 with 40 Quality Reference mAs) were displayed on a DICOM-compliant 55-inch 2-megapixel monitor for blinded evaluation by two thoracic radiologists for number and location of lesions, lesion size, lesion margins, visibility of small structures and fissures, and diagnostic confidence. Objective noise and CT values were measured in thoracic aorta for each image series, and the noise power spectrum was assessed. Data were analyzed with analysis of variance and Wilcoxon signed rank tests.RESULTS. All 186 lesions were seen on 40 Quality Reference mAs SAFIRE images. Diagnostic confidence on SAFIRE images was higher than that for FBP images. Except for the minor blotchy appearance on SAFIRE settings S3 and S4, no significant artifacts were noted. Objective noise with 40 Quality Reference mAs S1 images (21.1 +/- 6.1 SD of HU) was significantly lower than that for 40 Quality Reference mAs FBP images (28.5 +/- 8.1 SD of HU) (p andlt; 0.001). Noise power spectra were identical for SAFIRE and FBP with progressive noise reduction with higher iteration SAFIRE settings.CONCLUSION. Iterative reconstruction (SAFIRE) allows reducing the radiation exposure by approximately 65% without losing diagnostic information in chest CT.
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| 13. |
- Kemerink, Martijn, et al.
(författare)
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Editorial Material: The Application of X-Rays in Radiology: From Difficult and Dangerous to Simple and Safe in AMERICAN JOURNAL OF ROENTGENOLOGY, vol 198, issue 4, pp 754-759
- 2012
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Ingår i: American Journal of Roentgenology. - : AMER ROENTGEN RAY SOC. - 0361-803X .- 1546-3141. ; 198:4, s. 754-759
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- OBJECTIVE. This article will provide an assessment of the application of x-rays in the early days of radiology, which is an excellent way to come to value the convenience and safety of modern x-ray systems. CONCLUSION. The gas tubes that were originally applied for x-ray production were very unstable because of variations in the tubes vacuum. In an effort to understand some of the problems of these tubes and the high occupational exposure that was indirectly caused by the tubes erratic behavior, we measured x-ray output rates as a function of the gas pressure inside the tube. The pressure range for the optimal production of x-rays, using an original Ruhmkorff inductor as a high-voltage generator, was found to be narrow. With the vacuum changing over time, this might explain the many photographs from the first years of radiology with operators watching their unshielded tube, either with bare eyes or with a fluoroscope, and their own hand as a test object. This practice often led to severe damage of the hands and to many early deaths due to cancer. Today, after a century of technologic development of x-ray tubes and associated equipment, the total average effective dose of workers in radiology can be close to natural background levels.
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| 14. |
- Kim, Hae Young, et al.
(författare)
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CT in Differentiating Complicated From Uncomplicated Appendicitis: Presence of Any of 10 CT Features Versus Radiologists Gestalt Assessment
- 2019
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Ingår i: American Journal of Roentgenology. - : AMER ROENTGEN RAY SOC. - 0361-803X .- 1546-3141. ; 213:5, s. W218-W226
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE. The purpose of this study is to propose a sensitive CT criterion (the presence of any of 10 CT features) for complicated appendicitis that could be used in the nonoperative management of appendicitis and to compare the diagnostic performance of this sensitive CT criterion with that of gestalt assessment. MATERIALS AND METHODS. This retrospective study, which was conducted in a tertiary teaching hospital, included 100 patients with suspected appendicitis on CT. Complicated appendicitis, defined as gangrenous or perforated appendicitis, was pathologically or surgically confirmed in 32 patients. Six radiologists independently determined the presence of 10 previously reported CT features of complicated appendicitis (contrast enhancement defect of the appendiceal wall, abscess, extraluminal air, intraluminal air, extraluminal appendicolith, intraluminal appendicolith, moderate-to-severe periappendiceal fat stranding, periappendiceal fluid, ileus, and ascites) and rated the likelihood score for complicated appendicitis using gestalt assessment. The sensitivity and specificity of CT for complicated appendicitis were measured by the presence of any of 10 CT features (the any-of-10-features criterion) and by the radiologists gestalt assessment. Pooled sensitivity and specificity were compared using a generalized linear mixed model. RESULTS. The pooled sensitivity of the presence of any of 10 CT features was higher than that of gestalt assessment (92% vs 64%; difference, 28% [95% CI, 10-46%]; p amp;lt; 0.001), although the pooled specificity was lower (43% vs 76%; difference, -33% [95% CI, -48% to -17%]; p amp;lt; 0.001). CONCLUSION. The pooled sensitivity of the presence of any of 10 CT features was higher than that of gestalt assessment, at the cost of lower specificity. For prudent selection of patients who should receive nonoperative treatment of appendicitis, the any-of-10-features criterion may be used to decrease treatment failure associated with a false-negative diagnosis of complication.
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| 15. |
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| 16. |
- Löve, Askell, et al.
(författare)
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Hybrid Iterative Reconstruction Algorithm Improves Image Quality in Craniocervical CT Angiography.
- 2013
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Ingår i: American Journal of Roentgenology: diagnostic imaging and related sciences. - 1546-3141. ; 201:6, s. 861-866
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE. The purpose of this study was to evaluate the potential of a hybrid iterative reconstruction algorithm for improving image quality in craniocervical CT angiography (CTA) and to assess observer performance. SUBJECTS AND METHODS. Thirty patients (mean age, 58 years; range 16-80 years) underwent standard craniocervical CTA (volume CT dose index, 6.8 mGy, 2.8 mSv). Images were reconstructed using both filtered back projection (FBP) and a hybrid iterative reconstruction algorithm. Five neuroradiologists assessed general image quality and delineation of the vessel lumen in seven arterial segments using a 4-grade scale. Interobserver and intraobserver variability were determined. Mean attenuation and noise were measured and signal-to-noise and contrast-to-noise ratios calculated. Descriptive statistics are presented and data analyzed using linear mixed-effects models. RESULTS. In pooled data, image quality in iterative reconstruction was graded superior to FBP regarding all five quality criteria (p < 0.0001), with the greatest improvement observed in the vertebral arteries. Iterative reconstruction resulted in elimination of arterial segments graded poor. Interobserver percentage agreement was significantly better (p = 0.024) for iterative reconstruction (69%) than for FBP (66%) but worse than intraobserver percentage agreement (mean, 79%). Noise levels, signal-to-noise ratio, and contrast-to-noise ratio were significantly (p < 0.001) improved in iterative reconstruction at all measured levels. CONCLUSION. The iterative reconstruction algorithm significantly improves image quality in craniocervical CT, especially at the thoracic inlet. Despite careful study design, considerable interobserver and intraobserver variability was noted.
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| 17. |
- Maeder, Philippe P, et al.
(författare)
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Colloid cysts of the third ventricle: correlation of MR and CT findings with histology and chemical analysis
- 1990
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Ingår i: AJNR. - 1936-959X. ; 155:1, s. 135-141
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Tidskriftsartikel (refereegranskat)abstract
- Eight patients with colloid cysts of the third ventricle were examined with CT and MR. In six, surgical resection was performed and the material was subjected to histologic evaluation; the concentrations of trace elements were determined by particle-induced X-ray emission. Stereotaxic aspiration was performed in two. The investigation showed that colloid cysts are often iso- or hypodense relative to brain on CT (5/8), but sometimes have a center of increased density. Increased density did not correlate with increased concentration of calcium or other metals but did not correlate with high cholesterol content. Colloid cysts appear more heterogeneous on MR (6/8) than on CT (3/8), despite a homogeneous appearance at histology. High signal on short TR/TE sequences is correlated with a high cholesterol content. A marked shortening of the T2 relaxation time is often noticed in the central part of the cyst. Analysis of trace elements showed that this phenomenon is not related to the presence of metals with paramagnetic effects. Our analysis of the contents of colloid cysts does not support the theory that differing metallic concentrations are responsible for differences in MR signal intensity or CT density. We did find that increased CT density and high MR signal correlated with high cholesterol content.
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| 18. |
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| 19. |
- Mosavi, Firas, et al.
(författare)
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Whole-Body Diffusion-Weighted MRI Compared With 18F-NaF PET/CT for Detection of Bone Metastases in Patients With High-Risk Prostate Carcinoma
- 2012
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Ingår i: American Journal of Roentgenology. - 0361-803X .- 1546-3141. ; 199:5, s. 1114-1120
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE:The purpose of this study was to evaluate the accuracy of whole-body diffusion-weighted MRI (DWI) and 18F-NaF PET/CT for detection of bone metastases in patients with high-risk prostate cancer.SUBJECTS AND METHODS:Both patient- and lesion-based analyses were performed on 49 consecutive patients (median age, 67 years; age range, 57-80 years) with recently diagnosed high-risk prostate cancer. All patients underwent bone scintigraphy, whole-body MRI including DWI and 18F-NaF PET/CT before treatment. Bone scintigraphy, conventional MR images, and follow-up images were used as the standard of reference to evaluate 18F-NaF PET/CT and DWI.RESULTS:On patient-based analysis, five patients had skeletal metastases on reference imaging that both DWI and 18F-NaF PET/CT could verify, and 18F-NaF PET/CT and DWI showed false-positive findings in four and one patient, respectively. With lesion-based analysis, 18F-NaF PET/CT and DWI showed nine and five true-positive lesions, zero and four false-negative lesions, and seven and two false-positive lesions, respectively. Two patients with uncountable bone metastases were analyzed separately. In these patients, 18F-NaF PET/CT showed more bone metastases than did DWI.CONCLUSION:We believe 18F-NaF PET/CT is a sensitive modality for detection of bone metastases caused by prostate cancer. Whole-body DWI shows a higher specificity but lower sensitivity than 18F-NaF PET/CT. Future studies with a larger patient cohort along with analyses of costs and clinical availability are needed before implementation of these methods can be considered.
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| 20. |
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| 21. |
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| 22. |
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| 23. |
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| 24. |
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| 25. |
- Ross, Steffen, et al.
(författare)
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Postmortem Whole-Body MRI in Traumatic Causes of Death
- 2012
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Ingår i: American Journal of Roentgenology. - : American Roentgen Ray Society (ARRS). - 0361-803X .- 1546-3141. ; 199:6, s. 1186-1192
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE:The aim of this study was to determine the sensitivity and specificity of postmortem whole-body MRI for typical injuries resulting from traumatic causes of death.MATERIALS AND METHODS:Forty cases of accidental death were evaluated with postmortem whole-body MRI. Imaging was conducted according to a standard protocol, and each examination had an average duration of 90 minutes. The imaging findings were correlated with the autopsy findings, which served as the reference standard.RESULTS:MRI showed the main pathologic process leading to death in 39 of the 40 cases. The sensitivity of postmortem MRI ranged from 100% (pneumothorax) to 40% (fractures of the upper extremities). In general, MRI had a high level of performance for depicting soft-tissue lesions, such as subcutaneous hematoma (e.g., galeal hematoma with a sensitivity 95%). The sensitivity of MRI was remarkably lower for lesions of the upper abdominal organs (liver, 80%; spleen, 50%; pancreas, 60%; kidneys, 66%).CONCLUSION:Postmortem whole-body MRI had overall good performance for depicting traumatic findings in corpses and therefore may serve an important role as an adjunct to classic autopsy for the forensic examination of cases of traumatic cause of death. However, the reduced sensitivity of postmortem MRI for lacerations of the upper abdominal organs and the observed superimposition of antemortem findings and postmortem findings (e.g., in the pulmonary tissue) in this retrospective study suggest that whole-body postmortem MRI not be recommended as a replacement for classic autopsy.
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| 26. |
- Rubesova, Erika, et al.
(författare)
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Three-dimensional MRI volumetric measurements of the normal fetal colon
- 2009
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Ingår i: American Journal of Roentgenology. - United States : American Roentgen Ray Society. - 0361-803X .- 1546-3141. ; 192:3, s. 761-765
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The use of fetal MRI markedly improves characterization of abdominal congenital anomalies. Accurate prenatal diagnosis of the level and cause of congenital intestinal obstruction is desired for optimal parental counseling and perinatal care. Because accurate diagnosis would be aided by nomograms of colonic volume, this study was conducted to determine normal colonic volumes at different gestational ages. MATERIALS AND METHODS: This retrospective study consisted of a review of 83 fetal MRI examinations performed on fetuses with no gastrointestinal abnormalities. MRI was performed with a 1.5-T system. Axial, sagittal, and coronal T1-weighted fast gradient-refocused echo images were acquired at TR/TE, 165/2.6; flip angle, 90 degrees; matrix size, 384 x 192; slice thickness, 5 mm; field of view, 38 cm(2). Two investigators determined the region of interest in the colon by outlining areas of high signal intensity of meconium slice by slice. They then calculated colonic luminal volume in the regions of interest. Colonic luminal volumes were reported relative to gestational age and abdominal circumference. Normative curves were generated, and interobserver and intraobserver analyses were performed. RESULTS: Seventeen of the 83 fetuses (20%) were excluded because of movement artifacts on the images. Normal colonic luminal volume increased exponentially with gestational age and abdominal circumference. The range of colonic luminal volumes at 20-37 weeks' gestational age was 1.1-65 mL. Variation of volume was greater at advanced gestational age. Interobserver and intraobserver correlation was good. CONCLUSION: This study yielded preliminary volumetric measurements of the normal fetal colon at 20-37 weeks of gestational age that suggest the fetal colon grows exponentially.
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| 27. |
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| 28. |
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| 30. |
- Fredriksson, Nils Johan, 1979-, et al.
(författare)
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Systematic analysis of noncoding somatic mutations and gene expression alterations across 14 tumor types
- 2014
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Ingår i: Nature Genetics. - : Nature Publishing Group. - 1061-4036 .- 1546-1718. ; 46:12, s. 1258-1263
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Tidskriftsartikel (refereegranskat)abstract
- Somatic mutations in noncoding sequences are poorly explored in cancer, a rare exception being the recent identification of activating mutations in TERT regulatory DNA. Although this finding is suggestive of a general mechanism for oncogene activation, this hypothesis remains untested. Here we map somatic mutations in 505 tumor genomes across 14 cancer types and systematically screen for associations between mutations in regulatory regions and RNA-level changes. We identify recurrent promoter mutations in several genes but find that TERT mutations are exceptional in showing a strong and genome-wide significant association with increased expression. Detailed analysis of TERT across cancers shows that the strength of this association is highly variable and is strongest in copy number stable cancers such as thyroid carcinoma. We additionally propose that TERT promoter mutations control expression of the nearby gene CLPTM1L. Our analysis provides a detailed pan-cancer view of TERT transcriptional activation but finds no clear evidence for frequent oncogenic promoter mutations beyond TERT.
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