Faculty Bibliography

OBJECTIVE:The purpose of this study is to retrospectively assess the incremental value of contrast-enhanced MRI (CE-MRI) to T2-weighted MRI in the detection of postsurgical local recurrence of prostate cancer by readers of different experience levels, using biopsy as the reference standard. MATERIALS AND METHODS/METHODS:Fifty-two men with biochemical recurrence after prostatectomy underwent 1.5-T endorectal MRI with multiphase contrast-enhanced imaging and had biopsy within 3 months of MRI. Two radiologists (reader 1 had 1 year and reader 2 had 6 years of experience) independently reviewed each MRI study and classified the likelihood of recurrent cancer on a 5-point scale. Areas under receiver operating characteristic curves (A(z)) were calculated to assess readers' diagnostic performance with T2-weighted MRI alone and combined with CE-MRI. Interobserver agreement was assessed using Cohen kappa statistics. RESULTS:Thirty-three patients (63%) had biopsy-proven local recurrence of prostate cancer. With the addition of CE-MRI to T2-weighted imaging, the A(z) for cancer detection increased significantly for reader 1 (0.77 vs 0.85; p = 0.0435) but not for reader 2 (0.86 vs 0.88; p = 0.7294). The use of CE-MRI improved interobserver agreement from fair (κ = 0.39) to moderate (κ = 0.58). CONCLUSION/CONCLUSIONS:CE-MRI increased interobserver agreement and offered incremental value to T2-weighted MRI in the detection of locally recurrent prostate cancer for the relatively inexperienced reader.

PURPOSE/OBJECTIVE:To investigate the use of quantitative multiphasic contrast material-enhanced magnetic resonance (MR) imaging in differentiating between common benign and malignant histologic subtypes of renal cortical tumors. MATERIALS AND METHODS/METHODS:The institutional review board waived informed consent and approved this retrospective HIPAA-compliant study of 138 patients who underwent preoperative contrast-enhanced MR imaging during the period of January 2004-December 2008. At surgery, 152 renal tumors were identified (77 clear cell, 22 papillary, 18 chromophobe, and 10 unclassified carcinomas; 16 oncocytomas; nine angiomyolipomas). Three readers independently identified and measured the most-enhanced area in each tumor and placed corresponding regions of interest in similar positions on images from the precontrast, corticomedullary, nephrographic, and excretory phases. The percentage change in signal intensity (%SI change) between precontrast imaging and each postcontrast phase was calculated. Interreader agreement was evaluated by using the overall concordance correlation coefficient (OCC). A linear mixed-effects model was used to estimate and compare the trajectories of the means of log %SI change across all phases between the six histologic subtypes. RESULTS:Interreader agreement was substantial to almost perfect (OCC, 0.77-0.88). The %SI change differed significantly between clear cell carcinomas and papillary and chromophobe carcinomas in all phases of enhancement (P < .0001-.0120). In addition, %SI change was significantly higher in angiomyolipomas than in clear cell carcinomas, but only in the corticomedullary phase (P = .0231). Enhancement did not differ significantly between clear cell carcinoma and oncocytoma in any phase (P = .2081-.6000). CONCLUSION/CONCLUSIONS:Quantitative multiphase contrast-enhanced MR imaging offers a widely available, reproducible method to characterize several histologic subtypes of renal cortical tumors, although it does not aid differentiation between clear cell carcinomas and oncocytomas.

PURPOSE/OBJECTIVE:To prospectively evaluate the diagnostic performance of magnetic resonance imaging (MRI), (11)C-acetate positron emission tomography/computed tomography (PET/CT) and contrast-enhanced CT for bladder cancer staging, using whole-mount pathologic review of radical cystectomy and pelvic lymph node specimens as the reference standard. MATERIALS AND METHODS/METHODS:The institutional review board approved this prospective study, which was compliant with the Health Insurance Portability and Accountability Act. Written informed consent was obtained from 16 patients with histologically confirmed bladder cancer who underwent MRI, (11)C-acetate PET/CT and contrast-enhanced CT before radical cystectomy and pelvic lymph node dissection. Before imaging 4/16 patients had received intravesical Bacillus Calmette-Guérin treatment, 6 had received systemic chemotherapy, 3 had received both and 3 had received neither. Measures of diagnostic performance including accuracy, sensitivity and specificity were estimated separately for each imaging modality. RESULTS:MRI correctly staged 56% of patients (9/16), overstaged 38% (6/16) and understaged 6% (1/16). CT correctly staged 50% of patients (8/16), overstaged 44% (7/16) and understaged 6% (1/16). In 9 patients, (11)C-acetate PET/CT showed uptake within the bladder wall; the uptake was true-positive in 7 patients and false-positive in 2 patients. Of the remaining 7 patients, 5 had true-negative and 2 had false-negative PET/CT results for cancer in the bladder wall. For all modalities, staging accuracy was reduced in patients with a history of prior intravesical and/or systemic chemotherapy. CONCLUSION/CONCLUSIONS:In staging bladder cancer, MRI, (11)C-acetate PET/CT and CT displayed similar levels of accuracy. For all modalities, a history of intravesical and/or systemic chemotherapy affected staging accuracy.

PURPOSE/OBJECTIVE:To prospectively evaluate diagnostic performance of T2-weighted magnetic resonance (MR) imaging and MR spectroscopic imaging in detecting lesions stratified by pathologic volume and Gleason score in men with clinically determined low-risk prostate cancer. MATERIALS AND METHODS/METHODS:The institutional review board approved this prospective, HIPAA-compliant study. Written informed consent was obtained from 183 men with clinically low-risk prostate cancer (cT1-cT2a, Gleason score≤6 at biopsy, prostate-specific antigen [PSA] level<10 ng/mL [10 μg/L]) undergoing MR imaging before prostatectomy. By using a scale of 1-5 (score 1, definitely no tumor; score 5, definitely tumor), two radiologists independently scored likelihood of tumor per sextant on T2-weighted images. Two spectroscopists jointly recorded locations of lesions with metabolic features consistent with tumor on MR spectroscopic images. Whole-mount step-section histopathologic analysis constituted the reference standard. Diagnostic performance at sextant level (T2-weighted imaging) and detection sensitivities (T2-weighted imaging and MR spectroscopic imaging) for lesions of 0.5 cm3 or larger were calculated. RESULTS:For T2-weighted imaging, areas under the receiver operating characteristic curves for sextant-level detection were 0.77 (reader 1) and 0.82 (reader 2). For lesions of ≥0.5 cm3 and, 1<cm3, sensitivities were significantly lower when the lesion Gleason score was ≤6 (0.44 [reader 1] and 0.61 [reader 2]) rather than when the Gleason score was ≥7 (0.73, P=.02 [reader 1]; and 0.84, P=.05 [reader 2]). For lesions of ≥1 cm3, lesion Gleason score did not significantly affect sensitivity (0.83 [reader 1] and 1.00 [reader 2] for Gleason score≤6 vs 0.82 and 0.92 for Gleason score≥7; P≥.07). MR spectroscopic imaging sensitivity was low and was not significantly affected by pathologic lesion volume or Gleason score. CONCLUSION/CONCLUSIONS:In men with clinically low-risk prostate cancer, detection of lesions of <1 cm3 with T2-weighted imaging is significantly dependent on lesion Gleason score; detection of lesions of ≥1 cm3 is significantly better than detection of smaller lesions and is not affected by lesion Gleason score. The role of MR spectroscopic imaging alone in this population is limited.

PURPOSE/OBJECTIVE:A barrier to the acceptance of active surveillance for men with prostate cancer is the risk of underestimating the cancer burden on initial biopsy. We assessed the value of endorectal magnetic resonance imaging in predicting upgrading on confirmatory biopsy in men with low risk prostate cancer. MATERIALS AND METHODS/METHODS:A total of 388 consecutive men (mean age 60.6 years, range 33 to 89) with clinically low risk prostate cancer (initial biopsy Gleason score 6 or less, prostate specific antigen less than 10 ng/ml, clinical stage T2a or less) underwent endorectal magnetic resonance imaging before confirmatory biopsy. Three radiologists independently and retrospectively scored tumor visibility on endorectal magnetic resonance imaging using a 5-point scale (1-definitely no tumor to 5-definitely tumor). Inter-reader agreement was assessed with weighted kappa statistics. Associations between magnetic resonance imaging scores and confirmatory biopsy findings were evaluated using measures of diagnostic performance and multivariate logistic regression. RESULTS:On confirmatory biopsy, Gleason score was upgraded in 79 of 388 (20%) patients. Magnetic resonance imaging scores of 2 or less had a high negative predictive value (0.96-1.0) and specificity (0.95-1.0) for upgrading on confirmatory biopsy. A magnetic resonance imaging score of 5 was highly sensitive for upgrading on confirmatory biopsy (0.87-0.98). At multivariate analysis patients with higher magnetic resonance imaging scores were more likely to have disease upgraded on confirmatory biopsy (odds ratio 2.16-3.97). Inter-reader agreement and diagnostic performance were higher for the more experienced readers (kappa 0.41-0.61, AUC 0.76-0.79) than for the least experienced reader (kappa 0.15-0.39, AUC 0.61-0.69). Magnetic resonance imaging performed similarly in predicting low risk and very low risk (Gleason score 6, less than 3 positive cores, less than 50% involvement in all cores) prostate cancer. CONCLUSIONS:Adding endorectal magnetic resonance imaging to the initial clinical evaluation of men with clinically low risk prostate cancer helps predict findings on confirmatory biopsy and assess eligibility for active surveillance.

Ovarian cancer usually presents with widespread peritoneal dissemination. The accurate mapping of the disease determines the likelihood of optimal surgical cytoreduction, which, in turn, predicts patient outcome. Standard CT and MRI frequently fail to accurately map the extent of metastatic disease. Furthermore, pure anatomical imaging uses only size criteria when assessing treatment response overlooking functional tissue alterations that occur before any changes in tumor size or volume. In this review article we describe the added value of functional imaging techniques such as dynamic contrast-enhanced MRI, diffusion-weighted MRI and PET combined with CT in the evaluation of patients with primary and recurrent ovarian cancer. The combination of functional and anatomical information provided by these techniques may play an important role in accurate delineation of the disease, thus influencing treatment selection. Similarly, the integrated functional and anatomical approach may provide noninvasive treatment response and predictive biomarkers that are crucial in the era of personalized treatment. © 2011 Future Medicine Ltd.

PURPOSE/OBJECTIVE:To determine the prognostic importance of pleural effusions on preoperative computed tomographic (CT) images in patients with advanced epithelial ovarian cancer. MATERIALS AND METHODS/METHODS:The institutional review board waived informed consent for this HIPAA-compliant study of 203 patients with International Federation of Obstetrics and Gynecology stage III (n = 172) or IV (n = 31) epithelial ovarian cancer who underwent CT before primary cytoreductive surgery between 1997 and 2004 (mean age, 61 years; range, 37-96 years). Two radiologists retrospectively evaluated chest and/or abdominal CT images for pleural malignancy and the presence, size, and laterality of pleural effusions. To evaluate survival, Kaplan-Meier methods were used, with log-rank P values for comparisons. Multivariate analyses were conducted by using Cox proportional hazards regression. κ Statistics were calculated for interreader agreement. RESULTS:Median survival was 50 months (95% confidence interval [CI]: 45, 55 months) for patients with stage III disease and 41 months (95% CI: 27, 58 months) for patients with stage IV disease. Readers 1 and 2 found pleural effusions in 40 and 41 stage III and 20 and 21 stage IV patients, respectively. At multivariate analysis, after controlling for stage, age at surgery, preoperative serum CA-125 level, debulking status, and ascites, moderate-to-large pleural effusion on CT images was significantly associated with worse overall survival (reader 1: hazard ratio = 2.27 [95% CI: 1.31, 3.92], P < .01; reader 2: hazard ratio = 2.25 [95% CI: 1.26, 4.01], P = .02). Preoperative CA-125 level, debulking status, and ascites were also significant survival predictors (P ≤ .03 for all for both readers). Readers agreed substantially in distinguishing small from moderate-to-large effusions (κ = 0.764). CONCLUSION/CONCLUSIONS:Moderate-to-large pleural effusion on preoperative CT images in patients with stage III or IV epithelial ovarian cancer was independently associated with poorer overall survival after controlling for age, preoperative CA-125 level, surgical stage, ascites, and cytoreductive status.

PURPOSE/OBJECTIVE:To assess the value of magnetic resonance (MR) imaging in determining the site of origin of newly diagnosed uterine cancer (corpus vs cervix) when clinical and/or histologic evaluation is indeterminate. MATERIALS AND METHODS/METHODS:The Institutional Review Board approved and waived informed consent for this HIPAA-compliant study of 59 women (median age, 59 years; range, 28-84 years) who underwent pelvic MR imaging to determine the anatomic origin of uterine cancer. Two radiologists independently retrospectively assessed all MR imaging studies. In 48 patients who underwent hysterectomy, surgical pathologic findings were the reference standard, and overall test yields and diagnostic likelihood ratios were measured. Accuracy in detecting invasion of adjacent structures was also calculated. For the remaining patients, imaging and biopsy findings are presented descriptively. RESULTS:At hysterectomy, 32 patients had uterine corpus cancer and 16 had cervical cancer. Overall test yields for reader 1 and reader 2 were 0.85 and 0.88, respectively. When a reader attributed a tumor's origin to either the uterine corpus or cervix, the odds of the tumor originating from that site were 4.80-6.35 times greater than they would have been if no other information were available. Accuracy levels in detecting invasion of the myometrium, cervical stroma, parametria and/or adnexae, and vagina, respectively, were 72%, 69%, 74%, and 85% for reader 1 and 78%, 77%, 76%, and 85% for reader 2. CONCLUSION/CONCLUSIONS:MR imaging is useful for determining the anatomic origin of uterine cancer and provides helpful information regarding invasion of adjacent structures.

PURPOSE/OBJECTIVE:To assess the incremental value of diffusion-weighted (DW) magnetic resonance (MR) imaging over T2-weighted MR imaging at 3 T for prostate cancer detection and to investigate the use of the apparent diffusion coefficient (ADC) to characterize tumor aggressiveness, with whole-mount step-section pathologic analysis as the reference standard. MATERIALS AND METHODS/METHODS:The Internal Review Board approved this HIPAA-compliant retrospective study and waived informed consent. Fifty-one patients with prostate cancer (median age, 58 years; range, 46-74 years) underwent T2-weighted MR imaging and DW MR imaging (b values: 0 and 700 sec/mm(2) [n = 20] or 0 and 1000 sec/mm(2) [n = 31]) followed by prostatectomy. The prostate was divided into 12 regions; two readers provided a score for each region according to their level of suspicion for the presence of cancer on a five-point scale, first using T2-weighted MR imaging alone and then using T2-weighted MR imaging and the ADC map in conjunction. Areas under the receiver operating characteristic curve (AUCs) were estimated to evaluate performance. Generalized estimating equations were used to test the ADC difference between benign and malignant prostate regions and the association between ADCs and tumor Gleason scores. RESULTS:For tumor detection, the AUCs for readers 1 and 2 were 0.79 and 0.76, respectively, for T2-weighted MR imaging and 0.79 and 0.78, respectively, for T2-weighted MR imaging plus the ADC map. Mean ADCs for both cancerous and healthy prostatic regions were lower when DW MR imaging was performed with a b value of 1000 sec/mm(2) rather than 700 sec/mm(2). Regardless of the b value used, there was a significant difference in the mean ADC between malignant and benign prostate regions. A lower mean ADC was significantly associated with a higher tumor Gleason score (mean ADCs of [1.21, 1.10, 0.87, and 0.69] × 10(-3) mm(2)/sec were associated with Gleason score of 3 + 3, 3 + 4, 4 + 3, and 8 or higher, respectively; P = .017). CONCLUSION/CONCLUSIONS:Combined DW and T2-weighted MR imaging had similar performance to T2-weighted MR imaging alone for tumor detection; however, DW MR imaging provided additional quantitative information that significantly correlated with prostate cancer aggressiveness.