Temporal changes in magnetic resonance imaging appearance of adult granulosa cell tumor.

Granulosa cell tumors (GCTs) can have a wide variety of appearances on magnetic resonance imaging (MRI), ranging from entirely solid to multilocular cystic, suggesting that GCTs undergo remarkable morphological changes during growth. These temporal changes in MRI appearance of individual GCTs have not been documented. A 54-year-old asymptomatic postmenopausal woman was referred to our department for a small ovarian mass. This 3-cm solid mass showed high intensity on diffusion-weighted MRI and low intensity on apparent diffusion coefficient mapping. Close clinical follow-up was recommended, but she did not return to our hospital until the age of 63, when she was referred for a large ovarian tumor. MRI showed a 15-cm multilocular cyst containing a solid component with hemorrhaging. Postoperative diagnosis was adult GCT (AGCT). These temporal changes demonstrate a possible reason why GCTs can have such a wide range of MRI appearance. This knowledge might promote accurate preoperative diagnosis of AGCTs.

T1-weighted MR imaging of glioma at 3T: a comparative study of 3D MPRAGE vs. conventional 2D spin-echo imaging.

PURPOSE: This study aims to investigate difference between magnetization-prepared rapid gradient-echo imaging (MPRAGE) and spin-echo (SE) imaging for evaluating glioma on pre-contrast-enhanced (CE) and post-CE T1-weighted images at 3 T. MATERIALS AND METHODS: We retrospectively assessed pre-CE and post-CE T1-weighted images for tumor contrast in 64 consecutive glioma patients. RESULTS: In the nonenhancing tumors, the contrast was significantly clearer in MPRAGE than SE. In the enhancing tumors, post-CE contrast ratio was significantly higher in SE than MPRAGE, but when subtraction images are evaluated, the difference got smaller. CONCLUSION: MPRAGE can be a good substitute of SE for T1-weighted imaging of glioma.

Primary central nervous system lymphoma: is absence of intratumoral hemorrhage a characteristic finding on MRI?

BACKGROUND: Previous studies have shown that intratumoral hemorrhage is a common finding in glioblastoma multi-forme, but is rarely observed in primary central nervous system lymphoma. Our aim was to reevaluate whether intratumoral hemorrhage observed on T2-weighted imaging (T2WI) as gross intratumoral hemorrhage and on susceptibility-weighted imaging as intratumoral susceptibility signal can differentiate primary central nervous system lymphoma from glioblastoma multiforme. PATIENTS AND METHODS: A retrospective cohort of brain tumors from August 2008 to March 2013 was searched, and 58 patients (19 with primary central nervous system lymphoma, 39 with glioblastoma multiforme) satisfied the inclusion criteria. Absence of gross intratumoral hemorrhage was examined on T2WI, and an intratumoral susceptibility signal was graded using a 3-point scale on susceptibility-weighted imaging. Results were compared between primary central nervous system lymphoma and glioblastoma multiforme, and values of P < 0.05 were considered significant. RESULTS: Gross intratumoral hemorrhage on T2WI was absent in 15 patients (79%) with primary central nervous system lymphoma and 23 patients (59%) with glioblastoma multiforme. Absence of gross intratumoral hemorrhage could not differentiate between the two disorders (P = 0.20). However, intratumoral susceptibility signal grade 1 or 2 was diagnostic of primary central nervous system lymphoma with 78.9% sensitivity and 66.7% specificity (P < 0.001), irrespective of gross intratumoral hemorrhage. CONCLUSIONS: Low intratumoral susceptibility signal grades can differentiate primary central nervous system lymphoma from glioblastoma multiforme. However, specificity in this study was relatively low, and primary central nervous system lymphoma cannot be excluded based solely on the presence of an intratumoral susceptibility signal.

Grading glial tumors with amide proton transfer MR imaging: different analytical approaches.

Amide proton transfer (APT) magnetic resonance imaging is gaining attention for its capability for grading glial tumors. Usually, a representative slice is analyzed. Different definitions of tumor areas have been employed in previous studies. We hypothesized that the accuracy of APT imaging for brain tumor grading may depend upon the analytical methodology used, such as selection of regions of interest (ROIs), single or multiple tumor slices, and whether or not there is normalization to the contralateral white matter. This study was approved by the institutional review board, and written informed consent was waived. Twenty-six patients with histologically proven glial tumors underwent preoperative APT imaging with a three-dimensional gradient-echo sequence. Two neuroradiologists independently analyzed APT asymmetry (APTasym) images by placing ROIs on both a single representative slice (RS) and all slices including tumor (i.e. whole tumor: WT). ROIs indicating tumor extent were separately defined on both FLAIR and, if applicable, contrast-enhanced T1-weighted images (CE-T1WI), yielding four mean APTasym values (RS-FLAIR, WT-FLAIR, RS-CE-T1WI, and WT-CE-T1WI). The maximum values were also measured using small ROIs, and their differences among grades were evaluated. Receiver operating characteristic (ROC) curve analysis was also conducted on mean and maximum values. Intra-class correlation coefficients for inter-observer agreement were excellent. Significant differences were observed between high- and low-grade gliomas for all five methods (P < 0.01). ROC curve analysis found no statistically significant difference among them. This study clarifies that single-slice APT analysis is robust despite tumor heterogeneity, and can grade glial tumors with or without the use of contrast material.

Visualization of lenticulostriate arteries at 3T: Optimization of slice-selective off-resonance sinc pulse-prepared TOF-MRA and its comparison with flow-sensitive black-blood MRA.

RATIONALE AND OBJECTIVES: To optimize visualization of lenticulostriate artery (LSA) by time-of-flight (TOF) magnetic resonance angiography (MRA) with slice-selective off-resonance sinc (SORS) saturation transfer contrast pulses and to compare capability of optimal TOF-MRA and flow-sensitive black-blood (FSBB) MRA to visualize the LSA at 3T. MATERIALS AND METHODS: This study was approved by the local ethics committee, and written informed consent was obtained from all the subjects. TOF-MRA was optimized in 20 subjects by comparing SORS pulses of different flip angles: 0, 400°, and 750°. Numbers of LSAs were counted. The optimal TOF-MRA was compared to FSBB-MRA in 21 subjects. Images were evaluated by the numbers and length of visualized LSAs. RESULTS: LSAs were significantly more visualized in TOF-MRA with SORS pulses of 400° than others (P < .003). When the optimal TOF-MRA was compared to FSBB-MRA, the visualization of LSA using FSBB (mean branch numbers 11.1, 95% confidence interval (CI) 10.0-12.1; mean total length 236 mm, 95% CI 210-263 mm) was significantly better than using TOF (4.7, 95% CI 4.1-5.3; 78 mm, 95% CI 67-89 mm) for both numbers and length of the LSA (P < .0001). CONCLUSIONS: LSA visualization was best with 400° SORS pulses for TOF-MRA but FSBB-MRA was better than TOF-MRA, which indicates its clinical potential to investigate the LSA on a 3T magnetic resonance imaging.

[Usefulness of MRI prior to prostate needle biopsy in PSA gray zone].

To evaluate the diagnostic accuracy of prostate magnetic resonance imaging (MRI), we compared MRI findings with the results of biopsy as well as findings from specimens following total prostatectomy. The subjects consisted of 260 males who showed a prostate specific antigen (PSA) level in the gray zone (4 ng/ml ≤PSA <10 ng/ml) and also underwent digital rectal examination (DRE), transrectal ultrasound (TRUS), and MRI prior to prostate biopsy between April 2005 and December 2009. In Evaluation 1, the results of DRE/TRUS/MRI were compared with those of prostate biopsy. The biopsy-positive rate was higher in males positive in each examination. However, 24.8% of males negative in all examinations were biopsypositive. Thus, these examinations were considered to be inappropriate for secondary screening. In evaluation 2, the prostate was divided into 4 regions, and the findings from specimens following total prostatectomy were compared with MRI findings in each region. For the region containing prostate cancer, MRI showed a sensitivity of 26.0%, specificity of 98.3%, positive predictive value of 96.2%, and negative predictive value of 44. 4%. In patients with a Gleason score ≥7, cancer foci were more frequently detectable using MRI. MRI prior to prostate biopsy in patients in the PSA gray zone is inappropriate for secondary screening due to its low sensitivity. However, by virtue of its high positive predictive value, MRI is useful for determining patients indicated for biopsy, as well as DRE and TRUS. Accurate evaluation of the localization of all cancer lesions is difficult using MRI. However, when MRI findings are present, they frequently indicate the cancer lesion, which may be useful information for treatment.