Materials and Methods: Renal contrast-enhanced MR angiography was simulated for a variety of infusion schemes, assuming both correct and incorrect timing between data acquisition and contrast agent injection. In addition, the ethics committee approved the retrospective evaluation of clinical breath-hold renal contrast-enhanced MR angiographic studies obtained with automated detection of contrast agent arrival. Twenty-two studies were evaluated for their ability to depict the origin of renal arteries in patent vessels and for any signs of timing errors.

Results: Simulations showed that a completely artifactual stenosis or an artifactual overestimation of an existing stenosis at the renal artery origin can be caused by timing errors of the order of 5 seconds in examinations performed with contrast agent infusion rates compatible with or higher than those of hand injections. Lower infusion rates make the studies more likely to accurately depict the origin of the renal arteries. In approximately one-third of all clinical examinations, different contrast agent uptake rates were detected on the left and right sides of the body, and thus allowed us to confirm that it is often impossible to optimize depiction of both renal arteries. In three renal arteries, a signal void was found at the origin in a patent vessel, and delayed contrast agent arrival was confirmed.

Conclusion: Computer simulations and clinical examinations showed that timing errors impair the accurate depiction of renal artery origins.

© RSNA, 2008

Materials and Methods: This single-center retrospective analysis of 71 symptomatic fibroids in 66 women was approved by the institutional review board and was HIPAA-compliant. Patients were treated with MR imaging–guided focused ultrasound surgery. The volume of treated fibroid and nonperfused volume (NPV) were calculated with software, while symptom outcome was assessed with a symptom severity score (SSS). Fibroids were classified as hyperintense or hypointense relative to skeletal muscle on pretreatment T2-weighted MR images.

Results: Baseline volume of treated fibroids was 255.5 cm³ ± 201.7 (standard deviation), and baseline SSS was 61.5 ± 14.9. Both pretreatment fibroid signal intensity (SI) and posttreatment NPV predicted 12-month volume reduction independently: Fibroids with an NPV of at least 20% or with low SI both showed significantly larger volume reduction (17.0% ± 13.0 and 17.2% ± 20.1, respectively) than fibroids with an NPV less than 20% or with high SI (10.7% ± 18.2 and no significant change, respectively). Patients whose fibroids demonstrated an NPV of at least 20% also experienced a larger decrease in SSS than did patients with fibroids with an NPV less than 20% (50.1% ± 19.8 vs 32.6% ± 29.9).

Conclusion: Fibroids with low SI on pretreatment T2-weighted MR images were more likely to shrink than were ones with high SI. The larger the NPV immediately after treatment, the greater the volume reduction and symptom relief were. These findings may help both in selecting appropriate patients for MR-guided focused ultrasound surgery and in predicting patient outcome.

© RSNA, 2008

Materials and Methods: Institutional review board approval was obtained for this retrospective HIPAA-compliant review of medical records of 2600 consecutive patients undergoing CT urography. Of these, 838 CT urograms in 779 patients (449 men, mean age of 62 years, range of 27–92 years; 330 women, mean age of 56 years, range of 18–86 years) evaluated for hematuria or a history of urothelial cancer, who had undergone cystoscopy within 6 months of the CT urogram, were included in the study. Clinical reports of CT urograms containing a bladder lesion interpreted as suspicious for malignancy were classified as positive. All others were classified as negative. Cystoscopy reports were classified as positive if a lesion underwent biopsy or was resected or negative if no lesion was detected. Performance characteristics for both CT urography and cystoscopy were determined by using pathologic findings or clinical follow-up as the reference standard. Ninety-five percent confidence intervals were estimated for each test characteristic.

Results: The overall sensitivity, specificity, accuracy, positive predictive value, and negative predictive value (NPV) for bladder cancer detection were 79% (117 of 149), 94% (649 of 689), 91% (766 of 838), 75% (117 of 157), and 95% (649 of 681) for CT urography and 95% (142 of 149), 92% (634 of 689), 93% (776 of 838), 72% (142 of 197), and 99% (634 of 641) for cystoscopy. The NPV of CT urography was higher in patients evaluated for hematuria alone (98%, 589 of 603). However, the accuracy of CT urography was considerably lower in patients with a prior urothelial malignancy (78%, 123 of 158).

Conclusion: CT urography is an accurate noninvasive test for detecting bladder cancer in patients at risk for the disease. The high NPV of CT urography in patients with hematuria may obviate cystoscopy in selected patients.

© RSNA, 2008

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