Fast Spin-echo T2-weighted MR Images Research Articles

Tumor grade estımatıon of clear cell and papıllary renal cell carcınomas usıng contrast-enhanced MDCT and FSE T2 weıghted MR ımagıng: radıology-pathology correlatıon.

Discrimination of low grade (grade 1-2) renal tumors from high grade (grade 3-4) ones carries crucial importance in terms of the management of these patients and also in the decision-making of appropriate treatment strategies. Our aim was to investigate whether contrast-enhanced multidetector computed tomography (MDCT) and T2 weighted fast spin echo (FSE) magnetic resonance imaging (MRI) could play a specific role in the discrimination of low grade versus high grade tumors in clear cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma (pRCC) patients. In this study, we retrospectively evaluated 66 RCC patients based on histopathologic findings who had underwent either partial or total nephrectomies. Our cohort consisted of 52 ccRCC and 14 pRCC patients, of whom 50 were male (%76) and 16 were female (%24). Among the 52 ccRCC patients, 18 had both cortico-medullary phase contrast-enhanced CT and MRI, 15 had only cortico-medullary phase CT and 19 had only MRI examination. In the pRCC group, 8 patients had both cortico-medullary phase contrast-enhanced CT and MRI, 3 had only cortico-medullary phase CT and 3 had only MRI. We both calculated mean tumor attenuation values on cortico-medullary phase MDCT images as HU (hounsfield unit) and also tumor mean signal intensity values on FSE T2 weighted MR images, using both region of interest and whole lesion measurements including normal renal cortex. The obtained values were compared with the grading results of the ccRCC and pRCC tumors according to the WHO/International Society of Urological Pathology grading system. A significant positive correlation was found between the mean attenuation values of both tumor subtypes on cortico-medullary phase contrast-enhanced CT and their grades (p < 0.001). High grade tumors exhibited higher mean attenuation values (74.3 ± 22.3 HU) than the low grade tumors (55.2 ± 23.7 HU) in both subtypes. However, a statistically significant correlation was not found between the mean signal intensity values of the two tumor subtypes on FSE T2 weighted MR images and their grades (p > 0.05). Low grade tumors had a mean signal intensity value of 408.9 ± 44.6, while high grade tumors showed a value of 382.1 ± 44.2. The analysis of the ccRCC group patients, yielded a statistically significant correlation between the mean signal intensity values on T2 weighted images and tumor grading (p < 0.001). Low grade (grade 1-2) ccRCC patients exhibited higher mean signal intensity values (475.7 ± 51.3), as compared to those of high grade (grade 3-4) (418.5 ± 45.7) tumors. On the other hand, analysis of the pRCC group patients revealed that there was a significant correlation between the mean attenuation values of tumors on cortico-medullary phase contrast-enhanced CT and their grades (p < 0.001). High grade papillary subtype tumors (54.2 ± 25.2) showed higher mean attenuation values than the low grade (35.5 ± 18.8) ones. Contrast-enhanced MDCT and T2 weighted FSE MRI can play a considerable role in the discrimination of low grade versus high grade tumors of both subtype RCC patients. Thus, these non-invasive evaluation techniques may have positive impact on the determination of the management and treatment strategies of these patients.

Comparison of cortico-medullary phase contrast-enhanced MDCT and T2-weighted MR imaging in the histological subtype differentiation of renal cell carcinoma: radiology-pathology correlation.

PurposeRenal cell carcinoma (RCC) subtype differentiation is of crucial importance in the management and prognosis of these patients. In this study, we investigated the usefulness of unenhanced and cortico-medullary phase contrast-enhanced multidetector-row computed tomography (MDCT) and T2-weighted fast spin-echo (FSE) magnetic resonance imaging (MRI) modalities in the discrimination of the 3 main subtype RCC patients in correlation with their histopathological findings.Material and methodsA total of 80 pathologically proven RCC patients who had undergone either partial or total nephrectomy were retrospectively investigated in this study. Their histological subtypes were 54 clear cell renal cell carcinoma (ccRCC), 15 papillary renal cell carcinoma (pRCC), and 11 chromophobe renal cell carcinoma (cRCC), based on pathological evaluation. There were 62 male (77.5%) and 18 female (22.5%) patients. Among the 54 ccRCC patients, 29 patients had both non-contrast and cortico-medullary phase CT, 1 had only non-contrast CT, 5 only had cortico-medullary phase CT, and 38 had MRI examination. In the pRCC group, 10 patients had both non-contrast and cortico-medullary phase CT, 1 had only non-contrast CT, 1 had only cortico-medullary phase CT, and 12 had MRI. Finally, in the remaining 11 cRCC patients, 9 had both non-contrast and cortico-medullary phase CT, and only 5 had MRI. We calculated both tumour attenuation values as HU (Hounsfield units) on unenhanced and cortico-medullary phase MDCT images and also tumour mean signal intensity values on FSE T2-weighted MRI images by using the region of interest (ROI) including normal renal cortex measurements. Besides quantitative evaluation, we also performed qualitative visual assessment of tumours on contrast-enhanced MDCT and FSE T2-weighted MRI.ResultsThere was no statistically significant difference among the attenuation values of the 3 tumour subtypes on pre-contrast CT images. ccRCC demonstrated a prominent degree of contrast enhancement compared to the chromophobe and papillary ones on cortico-medullary phase MDCT. We found no statistically significant difference between chromophobe and papillary subtypes, although chromophobe tumours showed slightly higher attenuation values compared to papillary ones. ccRCCs usually demonstrated a heterogenous contrast enhancement on cortico-medullary phase CT images, while the papillary subtype usually had a homogenous appearance on visual assessment. On FSE T2-weighted MR images, the signal intensity values of ccRCC patients were found to be significantly higher than both chromophobe and papillary subtypes. Although cRCC patients had a prominently lower T2 signal intensity than clear cell subtype, there was no statistically significant signal intensity difference between chromophobe and papillary subtypes. Regarding visual assessment, papillary subtype tumours showed a mostly homogenous appearance on T2-weighted images and a statistically significant difference was present. On the other hand, there was no significant difference of visual assessment of the clear cell and chromophobe subtypes.ConclusionsThe measurement of the attenuation values on cortico-medullary phase MDCT and the mean signal intensity values on FSE T2-weighted MRI can provide useful information in the differentiation of RCC main subtypes. Also, visual assessment of tumours on both modalities can contribute to this issue by providing additional imaging properties.

Standard Normal Fetal Lung Volume by MRI Measurement

Background: Pulmonary hypoplasia is a significant decrease in lung volume by any cause in comparison to the normal volume for gestational age. Objectives: To evaluate the application of prenatal magnetic resonance imaging in order to predict pulmonary hypoplasia, measurement of fetal lung volume (FLV) was aimed to establish a reference data in normal fetuses. Patients and Methods: Three hundred forty two fetuses with abnormal ultrasound findings underwent fast spin-echo T2-weighted MR imaging at a single tertiary care hospital (Shahid Faghihi Hospital, Shiraz, Iran). Data of 241 fetuses at 18 - 36 weeks’ gestation without thoracic malformations were obtained for a FLV normative curve. To acquire a best-fit formula for the mean total fetal lung volume based on each gestational week with 95% confidence interval (CI), we used the regression model applied by Rypens et al. This resulted in a formula calculating the expected fetal lung volume based on gestational age. A one-sample t-test was also carried out to compare the mean total fetal lung volume at each gestational week with the expected mean total fetal lung volume predicted by the formula by Rypens et al., Meyers et al., and Osada et al. Results: Normal FLV increased with gestational age as the spread of values. The expected fetal lung volume was derived from the following formula: Fetal lung volume (mL) = 0.002 × (gestational age [GA]2.913), in which GA is gestational weeks. FLV in our population had a more consistent correlation with Japanese fetuses than European or American fetuses. Conclusion: In fetuses with normal lungs, FLV distribution against gestational age is simply measured prenatally with MR imaging. A single universal formula might not be suitable for fetuses worldwide. In our region, acquired data were more consistent with Asian normal values.

Case 267.

History A 28-year-old man presented with lifelong anejaculation, which had become an issue because of family planning. The patient had a history of normal erections and experienced the sensation of orgasm without ever ejaculating. On physical examination, both testes were present in the scrotum, with normal dimensions and a normal epididymis bilaterally. The patient had a slightly tender left testicle, and digital rectal examination findings were normal. The patient underwent further investigation for the possibility of retrograde ejaculation with urine cytology, the results of which were negative. Genetic testing was performed to exclude Y chromosome microdeletions. Serum-luteinizing and follicle-stimulating hormone levels were normal, with a borderline low level of testosterone (7.6 nmol/L; normal range, 8.0-29.0 nmol/L). All other pertinent laboratory results were noncontributory. Pelvic MRI was requested to exclude an anatomic cause of anejaculation. MRI was performed in accordance with the standard clinical prostate protocol, with a dynamic contrast material-enhanced study ( Figs 1 - 3 ). CT of the upper abdomen was also performed ( Fig 4 ). The patient subsequently underwent cystoscopy, which revealed an intravesicular fluid-filled mass near the left ureteric orifice ( Fig 5 ). Figure 1a: (a) Coronal and (b, c) axial fast spin-echo T2-weighted MR images of the pelvis, with b being superior to c. Figure 1b: (a) Coronal and (b, c) axial fast spin-echo T2-weighted MR images of the pelvis, with b being superior to c. Figure 1c: (a) Coronal and (b, c) axial fast spin-echo T2-weighted MR images of the pelvis, with b being superior to c. Figure 2a: (a) Coronal T2-weighted (repetition time msec/echo time msec, 4574/86.5) MR image of the pelvis. (b) Axial T2-weighted (3000/85.4) MR image of the pelvis. Figure 2b: (a) Coronal T2-weighted (repetition time msec/echo time msec, 4574/86.5) MR image of the pelvis. (b) Axial T2-weighted (3000/85.4) MR image of the pelvis. Figure 3: Unenhanced axial fat-saturated T1-weighted (6.2/3.1) MR images. Figure 4: Coronal CT urogram. Figure 5: Image obtained at cystoscopy.

Fast-recovery fast spin-echo T2-weighted MR imaging: a free-breathing alternative to fast spin-echo in the pediatric abdomen

In the mid 1990s, the fast spin-echo (FSE) and turbo spin-echo (TSE) T2-weighted (T2-W) sequences became available and are now widely accepted alternatives to conventional spin-echo sequences since they result in reduced acquisition times while maintaining tissue contrast. Since that time, there has been continued development of new sequences to further decrease acquisition times, minimize artifacts, and preserve lesion detection. The purpose of this pictorial essay is to qualitatively illustrate the newly available fast recovery (FR) FSE T2-W MR images of the abdomen compared with the images acquired using the routine FSE T2-W sequence in non-breath-hold studies in children.

Periarticular Bone Findings in Rheumatoid Arthritis: T2-Weighted Versus Contrast-Enhanced T1-Weighted MRI

The purpose of this study was to establish the relative predictive value of T2-weighted and contrast-enhanced T1-weighted MRI techniques for bone erosions that are evident on CT. Because it is known that MRI depicts abnormalities in the periarticular bone of patients with rheumatoid arthritis, we wanted to compare the outcomes of T2-weighted versus contrast-enhanced T1-weighted MRI techniques. Eleven patients with rheumatoid arthritis underwent CT imaging of their most affected wrist. Fast spin-echo T2-weighted MR images were then acquired with spectral fat saturation. Enhanced T1-weighted spin-echo images acquired before and after IV administration of gadopentetate dimeglumine were used to determine the percent enhancement. Imaging examinations were scored for 15 anatomic zones. The CT score was based on cortical bone erosion. The MR score was based on periarticular bone marrow signal alteration. Both T2-weighted MR images with spectral fat saturation and enhanced T1-weighted images were concordant for the presence or absence of bone abnormalities in 122 of 165 zones (74%). Of the 43 zones that were discordant for an abnormality by the two MR techniques, the T2-weighted images were positive in five zones, and enhanced T1-weighted images were positive in 38 zones (p < 0.001). Of the 43 zones that were discordant by the two MR techniques, enhanced T1-weighted images were concordant with CT in 20 zones, whereas the T2-weighted images were concordant with CT in 23 zones (p = 0.76). A greater proportion of lesions detected by the T2-weighted images were "edema-like" signal patterns. In rheumatoid arthritis, contrast-enhanced T1-weighted MRI depicts more periarticular bone abnormalities than fat-suppressed T2-weighted MRI. These MR techniques are equally predictive of frank, erosive disease that is evident on CT.

CT and MRI findings in KIT-weak or KIT-negative atypical gastrointestinal stromal tumors

The large majority of gastrointestinal stromal tumors (GIST) can be diagnosed on the basis of KIT immunoreactivity. However, some atypical tumors show weak or negative KIT expression. We studied the imaging characteristics of atypical GIST, reviewing CT and MRI findings in ten patients (eight men, two women; mean age 59 years) with atypical GIST. Radiological studies were evaluated by two radiologists by consensus and included CT and MR imaging in all patients. Pathological diagnoses were made from surgery and confirmed by the polymerase-chain reaction (PCR) to amplify both exons of the c-kit gene and PDGFRA gene. The CT and MR examinations revealed a heterogeneous mass of the stomach containing cystic regions and soft tissue elements in all cases. All lesions were extraluminal masses and had an exophytic epicenter. On T1-weighted MR images soft tissue elements of the tumors were of homogeneously low- (n=3) or iso-signal intensity (n=7) compared with the liver parenchyma. On fast spin-echo T2-weighted MR images soft tissue elements of all tumors showed cystic regions of significantly high signal intensity interspersed with septumlike structures of low signal intensity. All lesions exhibited homogeneously (n=4) or heterogeneously (n=6) mild to moderate enhancement of soft tissue elements. Despite the relatively small number of patients CT and MRI findings of atypical GIST are a submucosal mass with soft tissue elements and cystic regions.

Chronic hepatitis C activity: correlation with lymphadenopathy on MR imaging.

To study the MR appearance of lymph nodes in relation to activity of chronic active hepatitis C, we correlated the findings on MR imaging with a histologic grading of the activity level. Fifty patients with chronic active hepatitis C, who had MR imaging examinations and a related histology report from a liver biopsy obtained within 1 month of the MR imaging were chosen from our radiology database and studied retrospectively. All patients were examined over a 4-year period at a single institution to detect cirrhosis or hepatocellular carcinoma. We divided the 50 patients into the mild, moderate, or severe activity groups, according to their histology reports. Two radiologists, unaware of the histologic classifications, individually reviewed the MR images to observe the perihepatic locations, number, size (defined as the sum of the length-by-width products of the largest three nodes), and intensity of the lymph nodes relative to the spleen. The clinical records of the patients were reviewed to check the results of their liver function tests. The lymph node findings on MR imaging were compared with the histologically confirmed activity level of chronic hepatitis C. Forty-four (88.0%) of 50 patients had perihepatic lymph nodes larger than 5 mm on MR images, including 64.2% (9/14) of the patients with mild activity, 96.3% (26/27) of the patients with moderate activity, and 100% (9/9) of the patients with severe activity (p = 0.0034). The average number +/- the standard deviation (SD) of perihepatic lymph nodes was 2.5 +/- 1.8 in patients with mild activity, 5.6 +/- 2.2 in patients with moderate activity, and 8.3 +/- 3.5 in patients with severe activity (p = 0.0001). The average size (+/- SD) of the lymph nodes was 151.0 +/- 104.9 mm(2) in the mild activity group, 366.8 +/- 143.0 mm(2) in the moderate activity group, and 488.2 +/- 244.8 mm(2) in the severe activity group (p = 0.0001). On fat-saturated fast spin-echo T2-weighted MR images, the average number (+/- SD) of hyperintense nodes was 0.17 +/- 0.25 in the mild activity group, 1.7 +/- 0.80 in the moderate activity group, and 2.4 +/- 0.60 nodes in the severe activity group (p = 0.0001). No relationship between histologic activity and results from liver function tests was found. MR imaging depicts perihepatic lymph nodes in most patients with chronic hepatitis C. Lymph node number, size, and hyperintensity were related to the activity of chronic hepatitis C, but the results of liver function tests were not.

Fast Spin-Echo T2-Weighted MR Imaging of Tongue Cancer: the Value of Fat-suppression

Purpose: To compare the diagnostic efficacy of fast spin-echo (FSE) T2-weighted MR imaging with and with-out fat suppression. Materials and Methods: Twelve patients (7 men and 5 women; mean age, 48 years) with pathologically proven cancer of the tongue were included in this study. In all of these, FSE T2-weighted MR images with and without fat suppression were obtained in the same imaging planes before surgery or biopsy. Two radiologists visually compared the images thus obtained in terms of detection, extent, and conspicuity of the tumor, and the con-trast-to-noise ratio (CNR) of each tumor was also calculated. Results: In all patients, both imaging modalities were equal in terms of tumor detection. In 4 of 12(33%), the extent of the tumor was greater with fat suppression, while in eight (67%), it was almost the same both with and without. In ten patients (83%), the tumor was more conspicuous with fat suppression, and percentage CNRs were significantly higher with fat suppression than without (180 70% and 113 61%, respectively; p = 0.02). Conclusion: For the evaluation of patients with tongue cancer, fat-suppressed FSE T2-weighted MR imaging is superior to its conventional equivalent.

Gradient-recalled echo versus fast spin-echo T2-weighted MR imaging of the glenoid labrum: Michael J. Tuite, M.D., A. De Smet, M.D., M. Norris, M.D., J. Orwin, M.D.

Gradient-recalled echo versus fast spin-echo T2-weighted MR imaging of the glenoid labrum: Michael J. Tuite, M.D., A. De Smet, M.D., M. Norris, M.D., J. Orwin, M.D.