Materials and Methods: This study on computed tomographic (CT) phantoms did not require institutional review board approval. The renal compartments of a CT phantom were filled with iodinated contrast material diluted to attain attenuations of 40, 140, and 240 HU. Saline-filled cylinders simulating cysts of varying diameters (range, 0.7–3.0 cm) were serially suspended in the renal compartments and scanned at 80, 90, 100, 120, and 140 kVp in 16-detector (n = 3) and 64-detector (n = 2) CT scanners. Generalized estimating equations were used to determine predictors of cyst pseudoenhancement (defined as a >10 HU increase in cyst attenuation when the background renal attenuation increased from 40 to 140 or 240 HU).

Results: Pseudoenhancement was seen with higher frequency (59 [61%] of 96 cysts vs 52 [39%] of 132 cysts, P < .05) and magnitude (17 vs 13 HU, P < .005) with 64- rather than with 16-detector scanners. Pseudoenhancement was also seen with higher frequency (25 [42%] of 60 cysts vs 11 [18%] of 60 cysts, P < .005) and magnitude (18 vs 13 HU, P < .05) at 140 kVp than at 80 or 90 kVp. Cyst pseudoenhancement increased with higher background renal enhancement (P < .005) and smaller cyst diameter (P < .05). The number of detectors, peak tube voltage, renal parenchymal enhancement level, and cyst diameter were independent predictors of cyst pseudoenhancement.

Conclusion: Lower tube voltage settings may be useful when accurate differentiation between small renal cysts and solid masses is critical, particularly for 64-detector CT scanners.

© RSNA, 2008

Materials and Methods: Internal review board approval and informed consent were obtained for this study. Twenty women (mean age, 36.3 years) with intramyometrial leiomyomas were enrolled in this study. Single-section double-echo dynamic MR imaging was performed before GnRH agonist administration. T2-weighted images were obtained before and after two or three GnRH agonist injections (1.88 mg leuprorelin acetate). The steepest signal intensity (SI) upslope on T1-weighted images and the area under the curve (AUC) on R2* images were determined by using a 16 x 16-voxel matrix that was placed in the center of a leiomyoma. Pearson correlation analysis was performed to compare the percentage of volume reduction with SI upslope and AUC. Unpaired t test was performed to evaluate the difference between leiomyomas with AUC and SI upslope values that were less than or greater than the mean.

Results: Percentage of volume reduction ranged from 6.2% to 51.1%. The mean AUC and mean SI upslope were 39.2 and 9.83% per second, respectively. There was a significant correlation between the AUC and the percentage of volume reduction (r = 0.81, P < .001), although no significant correlation was observed between the SI upslope and the percentage of volume reduction. A significant difference in percentage of volume reduction was observed in leiomyomas by using mean AUC as a cutoff value (P = .003).

Conclusion: AUC on R2* images correlates with the efficacy of GnRH agonist before initiation of treatment for volume reduction of leiomyoma.

© RSNA, 2008

Materials and Methods: This study had institutional review board approval, and informed consent was obtained from all participants. There were 59 women: 15 nulliparous study control women (mean age, 25.6 years) and 44 patients (mean age, 43.4 years), who were divided into four groups according to chief symptom. Static T2-weighted turbo spin-echo images were used in evaluating structural derangements; functional dynamic (cine) balanced fast-field echo images were used in detecting functional abnormalities and recording five measurements of supporting structures. Findings on both types of MR images were analyzed together to determine the predominant defect. Analysis of variance and the Bonferroni t test were used to compare groups.

Results: In the four patient groups, POP was associated with levator muscle weakness in 16 (47%) of 34 patients, with level I and II fascial defects in seven (21%) of 34 patients, and with both defects in 11 (32%) of 34 patients. SUI was associated with defects of the urethral supporting structures in 25 (86%) of 29 patients but was not associated with bladder neck descent. Levator muscle weakness may lead to anal incontinence in the absence of anal sphincter defects. Measurements of supporting structures were significant (P < .05) in the identification of pelvic floor laxity.

Conclusion: Combined analysis of static and dynamic MR images of patients with pelvic floor dysfunction allowed identification of certain structural abnormalities with specific dysfunctions.

© RSNA, 2008

Materials and Methods: The institutional review board approved this study and waived the requirement for informed consent. Forty male patients aged 62–84 years (mean age, 71 years) who had prostate cancer underwent MR imaging of the prostate gland after ultrasonographically (US) guided systematic 12-core-specimen biopsy. The mean time between biopsy and MR imaging was 24 days (range, 6–54 days). T1-weighted, T2-weighted, dynamic contrast-enhanced, and DW imaging examinations were performed at 1.5 T. The prostate was divided, according to the biopsy sites, into eight regions on the MR images. Three reviewers in consensus evaluated each region for hemorrhage and prostate cancer. Statistical evaluations were performed with Mann-Whitney U, Ryan, and Spearman rank correlation tests.

Results: Intraglandular hemorrhage was observed in 38 (95%) patients and significantly more often in the peripheral zone (PZ) than in the transition zone (TZ) (P < .001). Degree of hemorrhage did not correlate significantly (P = .536) with time between biopsy and MR imaging. The sensitivity, specificity, and accuracy of combined T2-weighted, dynamic contrast-enhanced, and DW imaging in the diagnosis of prostate cancer were 69%, 85%, and 78%, respectively. Sensitivity and specificity were lower for the TZ than for the PZ. Degree of hemorrhage was significantly lower in regions of positive biopsy findings than in regions of negative biopsy findings (P = .001) and correlated negatively with tumor size (P = .043).

Conclusion: Interpretation of combined T2-weighted, dynamic contrast-enhanced, and DW MR image findings can yield reasonable diagnostic accuracy in both the PZ (80% [191 of 240 regions]) and the TZ (74% [59 of 80 regions]).

© RSNA, 2008

Materials and Methods: This study was conducted within local institutional review board guidelines, and written informed consent was obtained. In 223 clinically infertile men (age range, 18–50 years) with varicoceles and associated oligoteratoasthenospermia, endovascular embolization of the spermatic veins was performed with distal coil embolization and sclerotherapy. Additional anti-inflammatory treatment was initiated if required. Baseline clinical examination, semen specimen, and hormone level findings were compared to follow-up data. Posttreatment pregnancy rate of their healthy female partners was assessed with a standardized questionnaire. Unconditioned logistic regression was used to identify factors among all available clinical and laboratory data predicting treatment success (sired pregnancy during follow-up).

Results: A total of 226 of 228 varicoceles in 223 patients were successfully treated. Resolution of varicoceles at clinical examination and ultrasonography (US) was observed in 206 patients (92.4%). Three-month follow-up semen analysis in these patients showed significant improvement in sperm motility (P < .001) and sperm count (P < .001); however, average values remained in the abnormal range (World Health Organization guidelines). In 173 patients, follow-up data were successfully obtained, with pregnancy reported in 45 (26%). Baseline sperm motility was identified as the only significant pretreatment factor (standardized regression coefficient β = 3.285, t = 7.560, P = .006) predicting sired pregnancy. Hormone levels, clinical grading of varicoceles, Doppler US findings, and other semen parameters did not reach statistical significance.

Conclusion: Sperm motility prior to varicocele treatment in infertile men is an important predictor of later pregnancy.

© RSNA, 2008

Materials and Methods: A fat-saline phantom was used to perform IP and OP 3.0-T MR imaging for various fat fractions. The institutional review board approved this HIPAA-compliant study, with waiver of informed consent. Single-breath-hold IP and OP 3.0-T MR images in 21 patients (14 women, seven men; mean age, 63 years) with 23 adrenal tumors (16 adenomas, six metastases, one adrenocortical carcinoma) were reviewed. The MR protocol involved two acquisition schemes: In scheme A, the first OP echo (approximately 1.5-msec TE) and the second IP echo (approximately 4.9-msec TE) were acquired. In scheme B, the first IP echo (approximately 2.4-msec TE) and the third OP echo (approximately 5.8-msec TE) were acquired. Quantitative analysis was performed, and analysis of variance was used to test for differences between adenomas and nonadenomas.

Results: In the phantom study, scheme B did not enable discrimination among voxels that had small amounts of fat. In the clinical study, no overlap in signal intensity (SI) index values between adenomas and nonadenomas was seen (P < .05) with scheme A. However, with scheme B, no overlap in the adrenal gland SI–to–liver SI ratio between adenomas and nonadenomas was seen (P < .05). With scheme B, no overlap in adrenal gland SI index–to–liver SI index ratio between adenomas and nonadenomas was seen (P < .05).

Conclusion: This initial experience indicates SI index is the most reliable parameter for characterization of adrenal tumors with 3.0-T MR imaging when obtaining OP echo before IP echo. When acquiring IP echo before OP echo, however, nonadenomas can be mistaken as adenomas with use of the SI index value.

© RSNA, 2008

Materials and Methods: Ethics committee approval was obtained, with waiver of informed consent. Patients consented to having their data used for future retrospective research. Forty-one women (age range, 22–73 years) with 48 epithelial ovarian tumors underwent dynamic contrast-enhanced MR imaging before surgical excision. In case of bilateral tumors (n = 7), only the most complex tumor was analyzed. Thus, 41 tumors (12 benign, 13 borderline, and 16 invasive) were examined with dynamic contrast-enhanced MR imaging and immunohistochemical methods. Dynamic contrast-enhanced MR imaging parameters (enhancement amplitude [EA], time of half rising [T_max], and maximal slope [MS]) were analyzed according to histopathologic findings, microvessel density, pericyte coverage index (PCI), and vascular endothelial growth factor receptor 2 (VEGFR-2) expression. Statistical analyses were performed by using Kruskal-Wallis, Fisher exact, and Spearman tests and receiver operating curve analysis.

Results: EA was higher for invasive tumors than for benign (P < .001) and borderline (P < .05) tumors. T_max was longer for benign tumors than for borderline (P < .05) and invasive (P < .01) tumors. MS was steeper for invasive tumors than for benign (P < .001) and borderline (P < .001) tumors. PCI was lower in invasive tumors than in borderline (P < .05) and benign (P < .05) tumors. Microvessels showed stronger immunohistochemical VEGFR-2 expression in invasive tumors than in benign or borderline tumors (P < .05). MS correlated with a lower PCI (r = –0.34, P = .04) and stronger VEGFR-2 expression by using both epithelial (r = 0.41, P < .01) and endothelial (r = 0.66, P < .001) cells.

Conclusion: The early enhancement patterns of ovarian epithelial tumors on dynamic contrast-enhanced MR images can help distinguish among benign, borderline, and invasive tumors and were found to correlate with tumoral angiogenic status.

© RSNA, 2008

Materials and Methods: The human studies committee approved this HIPAA-complaint study, with waiver of informed consent. Patients with pathologically proved AMLs lacking visible macroscopic fat at CT and patients with pathologically proved CCRCCs were included. Lesions were measured, and a histogram (number of pixels with each attenuation) was calculated electronically within a central region of interest. The percentage of pixels below the attenuation thresholds –20 HU and 10 HU was calculated in both cohorts. The unpaired Student t test was used to compare the average percentage of subthreshold pixels at each threshold. P < .05 indicated a significant difference. The number of lesions with more than the selected percentage of subthreshold pixels was calculated in both groups, and the ² test was used to test the significance of differences between cohorts. The area under the receiver operating characteristic (ROC) curve was used to determine if any percentage of subthreshold pixels could be used to differentiate between the two cohorts.

Results: There were 22 patients with pathologically proved AMLs lacking visible macroscopic fat on CT images. Tuberous sclerosis affected three of these patients. Mean maximal transverse lesion diameter was 20 mm (range, 11–38 mm). There were 28 patients in the CCRCC comparison group. Mean maximal transverse lesion diameter was 26 mm (range, 15–36 mm). Neither the Student t test (P > .2 for all thresholds <0 HU) nor the ² test (P > .15 for all thresholds <0 HU) revealed a significant difference between cohorts. A lesion with more low-attenuation pixels was significantly more likely to be characterized as CCRCC than as AML with ROC curve analysis.

Conclusion: Once AMLs with visible fat on CT images are excluded, pixel histogram analysis cannot be used to distinguish between AMLs and CCRCCs.

© RSNA, 2008

Materials and Methods: Institutional review board approval was obtained, and informed consent was waived for this retrospective HIPAA-compliant study. Triple-phase 16– or 64–detector row CT urographic images in 166 patients (88 men, 78 women; mean age, 58.9 years; range, 22–89 years) were evaluated retrospectively. Immediately prior to excretory phase scanning, 67 patients did and 99 did not undergo a log-rolling procedure on the CT table. PVR bladder urine volume was quantified as the largest cross-sectional area of the bladder measured on unenhanced images (PVR values). The degree of bladder opacification was quantified as the percentage of the total cross-sectional area of the bladder that was opacified on excretory phase images. Ureteral opacification was quantified as the percentage of ureteral length that contained enhanced urine. On the basis of PVR values, patients were stratified into four subgroups (≤2000, >2000 to ≤3000, >3000 to ≤4000, and >4000 mm²). The Wilcoxon rank sum and Student t tests were used to evaluate differences.

Results: Median degree of bladder opacification of the log-rolling versus non–log-rolling group was 100% versus 78% for PVR values of 2000 mm² or less (P < .01), 99% versus 79% for PVR values of more than 2000 to 3000 mm² or less (P = .01), 89% versus 79% for PVR values of more than 3000 to 4000 mm² or less (P < .05), and 64% versus 69% for PVR values of more than 4000 mm² (P = .96). There was no significant difference between ureteral opacification and log rolling or between bladder and ureteral opacification (P > .05).

Conclusion: Use of a log-rolling procedure prior to excretory phase CT urography increases the percentage of bladder opacification in patients with PVR values of 4000 mm² or less. No difference in ureteral opacification was observed between the log-rolling and non–log-rolling groups.

© RSNA, 2008

Materials and Methods: The study was approved by the local ethics committee, and written informed consent was obtained from all patients. BOLD MR imaging was performed in 10 male patients (mean age, 45 years ± 17 [standard deviation]; range, 20–73 years) with a distal unilateral ureteral calculus and in 10 healthy age-matched male volunteers to estimate R2*, which is inversely related to tissue Po₂. R2* values were determined in the cortex and medulla of the obstructed and the contralateral nonobstructed kidneys. To reduce external effects on R2*, the R2* ratio between the medulla and cortex was also analyzed. Statistical analysis was performed with nonparametric rank tests. P < .05 was considered to indicate a significant difference.

Results: All patients had significantly lower medullary and cortical R2* values in the obstructed kidney (median R2* in medulla, 10.9 sec^–1 [range, 9.1–14.3 sec^–1]; median R2* in cortex, 10.4 sec^–1 [range, 9.7–11.3 sec^–1]) than in the nonobstructed kidney (median R2* in medulla, 17.2 sec^–1 [range, 14.6–23.2 sec^–1], P = .005; median R2* in cortex, 11.7 sec^–1 [range, 11.0–14.0 sec^–1], P = .005); values in the obstructed kidneys were also significantly lower than values in the kidneys of healthy control subjects (median R2* in medulla, 16.1 sec^–1 [range, 13.9–18.1 sec^–1], P < .001; median R2* in cortex, 11.6 sec^–1 [range, 10.5–12.9 sec^–1], P < .001). R2* ratios in the obstructed kidneys (median, 1.06; range, 0.85–1.27) were significantly lower than those in the nonobstructed kidneys (median, 1.49; range, 1.26–1.71; P = .005) and those in the kidneys of healthy control subjects (median, 1.38; range, 1.23–1.47; P < .001). In contrast, R2* ratios in the nonobstructed kidneys of patients were significantly higher than those in kidneys of healthy control subjects (P = .01).

Conclusion: Increased oxygen content in the renal cortex and medulla occurs with acute unilateral ureteral obstruction, suggesting reduced function of the affected kidney.

© RSNA, 2008