Faculty Bibliography

OBJECTIVES/OBJECTIVE:The aim of this study was to assess the diagnostic performance of pre-treatment 3-Tesla (3T) multiparametric magnetic resonance imaging (mpMRI) for predicting Gleason score (GS) downgrading after radical prostatectomy (RP) in patients with GS 3 + 4 prostate cancer (PCa) on biopsy. METHODS:We retrospectively reviewed 304 patients with biopsy-proven GS 3 + 4 PCa who underwent mpMRI before RP. On T2-weighted imaging and three mpMRI combinations (T2-weighted imaging + diffusion-weighted imaging [DWI], T2-weighted imaging + dynamic contrast-enhanced-MRI [DCE-MRI], and T2-weighted imaging + DWI + DCE-MRI), two radiologists (R1/R2) scored the presence of a dominant tumour using a 5-point Likert scale (1 = definitely absent to 5 = definitely present). Diagnostic performance in identifying downgrading was evaluated via areas under the curves (AUCs). Predictive accuracies of multivariate models were calculated. RESULTS:In predicting downgrading, T2-weighted imaging + DWI (AUC = 0.89/0.85 for R1/R2) performed significantly better than T2-weighted imaging alone (AUC = 0.72/0.73; p < 0.001/p = 0.02 for R1/R2), while T2-weighted imaging + DWI + DCE-MRI (AUC = 0.89/0.84 for R1/R2) performed no better than T2-weighted imaging + DWI (p = 0.48/p > 0.99 for R1/R2). On multivariate analysis, the clinical + mpMRI model incorporating T2-weighted imaging + DWI (AUC = 0.92/0.88 for R1/R2) predicted downgrading significantly better than the clinical model (AUC = 0.73; p < 0.001 for R1/R2). CONCLUSION/CONCLUSIONS:mpMRI improves the ability to identify a subgroup of patients with Gleason 3 + 4 PCa on biopsy who are candidates for active surveillance. DCE-MRI (compared to T2 + DWI) offered no additional benefit to the prediction of downgrading. KEY POINTS/CONCLUSIONS:Diagnostic performance of T2-weighted-imaging + DWI was better than T2-weighted-imaging alone. Diagnostic performance of T2-weighted-imaging + DWI was similar to T2-weighted-imaging + DWI + DCE-MRI. Combining clinical and T2-weighted-imaging + DWI features best predicted GS downgrading. mpMRI might prevent overtreatment by increasing eligibility for PCa active surveillance.

OBJECTIVE:The purpose of this study was to evaluate the usefulness and diagnostic performance of a 5-point standardized diagnostic certainty lexicon for reporting the likelihood of extracapsular extension (ECE) of prostate cancer on routine staging prostate MRI. MATERIALS AND METHODS/METHODS:This study was a retrospective analysis of routine clinical prostate MRI reports before (254 patients) and after (211 patients) the implementation of a 5-point diagnostic certainty lexicon. Whole-mount step-section pathology of the radical prostatectomy specimens served as the reference standard. The terms used to express diagnostic certainty regarding ECE on standard-of-care MRI and the presence of ECE on pathology were compared between the two periods. ROC analysis was used to evaluate the diagnostic accuracy of the 5-point certainty lexicon for detecting ECE. RESULTS:Before the implementation of the certainty lexicon, radiologists used 38 different terms to express the levels of certainty regarding the presence of ECE on MRI. Afterward, they adhered to the lexicon's predefined 5-point terminology in 85.3% of cases. The 5-point certainty lexicon used on MRI reports had an AUC of 0.852 for diagnosing ECE. CONCLUSION/CONCLUSIONS:The implementation of a lexicon of diagnostic certainty dramatically reduced the number of expressions used by radiologists to indicate their levels of diagnostic certainty. The accuracy of the certainty lexicon for diagnosing ECE on standard-of-care prostate MRI is similar to previously reported accuracy values for the diagnosis of ECE by MRI. Thus, the use of such a lexicon might prevent miscommunication and help referring clinicians reliably incorporate radiologists' assessments into clinical decision making.

INTRODUCTION/BACKGROUND:The high incidence of prostate cancer, coupled with excellent prostate cancer control rates, has resulted in growing interest in nononcological survivorship issues such as sexual function. Multiparametric magnetic resonance imaging (MRI) is increasingly being performed for local staging of prostate cancer, and due to the close anatomical relationship to the prostate, penile enhancement is often depicted in prostate MRI. AIM/OBJECTIVE:To evaluate the associations between quantitative perfusion-related parameters derived from dynamic contrast-enhanced (DCE)-MRI of the penis and self-reported sexual function in patients with newly diagnosed prostate cancer. METHODS:This retrospective study included 50 patients who underwent DCE-MRI for prostate cancer staging before prostatectomy. The following perfusion-related parameters were calculated: volume transfer constant (K(trans)), rate constant (k(ep)), extracellular-extravascular volume fraction (v(e)), contrast enhancement ratio (CER), area under the gadolinium curve after 180 seconds (AUC180), and slope of the time/signal intensity curve of the corpora cavernosa. Associations between perfusion-related parameters and self-reported sexual function were evaluated using the Wilcoxon Rank-Sum test. MAIN OUTCOME MEASURES/METHODS:Patient responses to the sexual function domain of the Prostate Quality of Life survey. RESULTS:Five of the six DCE-MRI parameters (K(trans), v(e), CER, AUC180, and slope) were significantly associated with the overall score from the sexual domain of the survey (P = 0.0020-0.0252). CER, AUC180, and slope were significantly associated with the answers to all six questions (P = 0.0020-0.0483), ve was significantly associated with the answers to five of six questions (P = 0.0036-0.1029), and K(trans) was significantly associated with the answers to three of six questions (P = 0.0252-0.1023). k(ep) was not significantly associated with the overall survey score (P = 0.7665) or the answers to any individual questions (P = 0.4885-0.8073). CONCLUSION/CONCLUSIONS:Penile DCE-MRI parameters were significantly associated with self-reported sexual function in patients with prostate cancer. These parameters are readily available when performing prostate MRI for staging and may be relevant to the management of patients considering prostate cancer therapies.

PURPOSE/OBJECTIVE:To investigate whether tumor volume derived from apparent diffusion coefficient (ADC) maps (VolumeADC) and tumor mean ADC value (ADCmean) are independent predictors of prostate tumor Gleason score (GS). EXPERIMENTAL DESIGN/METHODS:Tumor volume and GS were recorded from whole-mount histopathology for 131 men (median age, 60 years) who underwent endorectal diffusion-weighted MRI for local staging of prostate cancer before prostatectomy. VolumeADC and ADCmean were derived from ADC maps and correlated with histopathologic tumor volume and GS. Univariate and multivariate analyses were performed to evaluate prediction of tumor aggressiveness. Areas under receiver-operating characteristics curves (AUC) were calculated to evaluate the performance of VolumeADC and ADCmean in discriminating tumors of GS 6 and GS ≥7. RESULTS:Histopathology identified 116 tumor foci >0.5 mL. VolumeADC correlated significantly with histopathologic tumor volume (ρ = 0.683). The correlation increased with increasing GS (ρ = 0.453 for GS 6 tumors; ρ = 0.643 for GS 7 tumors; ρ = 0.980 for GS ≥8 tumors). Both VolumeADC (ρ = 0.286) and ADCmean (ρ = -0.309) correlated with GS. At univariate analysis, both VolumeADC (P = 0.0325) and ADCmean (P = 0.0033) could differentiate GS = 6 from GS ≥7 tumor foci. However, at multivariate analysis, only ADCmean (P = 0.0156) was a significant predictor of tumor aggressiveness (i.e., GS 6 vs. GS ≥7). For differentiating GS 6 from GS ≥7 tumors, AUCs were 0.644 and 0.704 for VolumeADC and ADCmean, respectively, and 0.749 for both parameters combined. CONCLUSION/CONCLUSIONS:In patients with prostate cancer, ADCmean is an independent predictor of tumor aggressiveness, but VolumeADC is not. The latter parameter adds little to the ADCmean in predicting tumor GS.

OBJECTIVE:To determine the associations of quantitative parameters derived from multiphase contrast-enhanced magnetic resonance imaging (CE-MRI), diffusion-weighted (DW) MRI and 18F-fluorodeoxyglucose (18F-FDG) positron-emission tomography/computed tomography (PET/CT) with clinico-histopathological prognostic factors, disease-free survival (DFS) and overall survival (OS) in patients with cervical cancer. METHODS AND MATERIALS/METHODS:Our institutional review board approved this retrospective study of 49 patients (median age, 45 years) with histopathologically proven IB-IVB International Federation of Gynecology and Obstetrics (FIGO) cervical cancer who underwent pre-treatment pelvic MRI and whole-body 18F-FDG PET/CT between February 2009 and May 2012. Maximum diameter (maxTD), percentage enhancement (PE) and mean apparent diffusion coefficient (ADCmean) of the primary tumor were measured on MRI. Maximum standardized uptake value (SUVmax), metabolic tumor volume (MTV), total lesion glycolysis (TLG) were measured on 18F-FDG PET/CT. Correlations between imaging metrics and clinico-histopathological parameters including revised 2009 FIGO stage, tumor histology, grade and lymph node (LN) metastasis at diagnosis were evaluated using the Wilcoxon rank sum test. Cox modeling was used to determine associations with DFS and OS. RESULTS:Median follow-up was 17 months. 41 patients (83.6%) were alive. 8 patients (16.3%) died of disease. Progression/recurrence occurred in 17 patients (34.6%). Significant differences were observed in ADCmean, SUVmax, MTV and TLG according to FIGO stage (p<0.001-0.025). There were significant correlations between ADCmean, MTV, TLG and LN metastasis (p=0.017-0.032). SUVmax was not associated with LN metastasis. FIGO stage (p=0.017/0.033), LN metastases (p=0.001/0.020), ADCmean (p=0.007/0.020) and MTV (p=0.014/0.026) were adverse predictors of both DFS/OS. maxTD (p=0.005) and TLG (p=0.024) were adverse predictors of DFS. PE and SUVmax did not correlate with DFS or OS (p=0.18-0.72). CONCLUSIONS:Quantitative parameters derived from pre-treatment DW-MRI (ADCmean) and from 18F-FDG PET/CT (MTV and TLG) were associated with high-risk features and may serve as prognostic biomarkers of survival in patients with cervical cancer.

PURPOSE/OBJECTIVE:Parastomal hernia is a frequent complication of stoma formation after radical cystectomy. We determined the prevalence and risk factors for the development of parastomal hernia after radical cystectomy. MATERIALS AND METHODS/METHODS:We conducted a retrospective study of 433 consecutive patients who underwent open radical cystectomy and ileal conduit between 2006 and 2010. Postoperative cross-sectional imaging studies performed for routine oncologic followup (1,736) were evaluated for parastomal hernia, defined as radiographic evidence of protrusion of abdominal contents through the abdominal wall defect created by forming the stoma. Univariable and multivariable Cox regression analyses were used to determine clinical and surgical factors associated with parastomal hernia. RESULTS:Complete data were available for 386 patients with radiographic parastomal hernia occurring in 136. The risk of a parastomal hernia developing was 27% (95% CI 22, 33) and 48% (95% CI 42, 55) at 1 and 2 years, respectively. Clinical diagnosis of parastomal hernia was documented in 93 patients and 37 were symptomatic. Of 16 patients with clinical parastomal hernia referred for repair 8 had surgery. On multivariable analysis female gender (HR 2.25; 95% CI 1.58, 3.21; p<0.0001), higher body mass index (HR 1.08 per unit increase; 95% CI 1.05, 1.12; p<0.0001) and lower preoperative albumin (HR 0.43 per gm/dl; 95% CI 0.25, 0.75; p=0.003) were significantly associated with parastomal hernia. CONCLUSIONS:The overall risk of radiographic evidence of parastomal hernia approached 50% at 2 years. Female gender, higher body mass index and lower preoperative albumin were most associated with the development of parastomal hernia. Identifying those at greatest risk may allow for prospective surgical maneuvers at the time of initial surgery, such as placement of prophylactic mesh in selected patients, to prevent the occurrence of parastomal hernia.

Different treatment options are available for patients with gynecological cancers. Imaging plays an important role in assessment of patients with common cancers involving uterine body, cervix and ovaries, from detection to evaluation of the extent of disease. The purpose of this review is to highlight the role of cross-sectional imaging techniques in treatment stratification and overall management of patients with endometrial, cervical and ovarian cancers. Several imaging techniques used are described, including ultrasound, computed tomography (CT), MRI and PET/CT. Specific imaging appearances of the most common uterine, cervical and ovarian cancers are discussed. Imaging findings corresponding to the 2009 revised International Federation of Gynecology and Obstetrics (FIGO) staging of gynecologic malignancies are also described. In the multidisciplinary evaluation of patients with gynecologic malignancies, the role of the radiologist has become central for accurate diagnosis and evaluation of extent of disease to achieve better treatment selection and planning.

PURPOSE/OBJECTIVE:To compare the features of bone metastases at computed tomography (CT) to tracer uptake at fluorine 18 fluorodeoxyglucose (FDG) positron emission tomography (PET) and fluorine 18 16β-fluoro-5-dihydrotestosterone (FDHT) PET and to determine associations between these imaging features and overall survival in men with castration-resistant prostate cancer. MATERIALS AND METHODS/METHODS:This is a retrospective study of 38 patients with castration-resistant prostate cancer. Two readers independently evaluated CT, FDG PET, and FDHT PET features of bone metastases. Associations between imaging findings and overall survival were determined by using univariate Cox proportional hazards regression. RESULTS:In 38 patients, reader 1 detected 881 lesions and reader 2 detected 867 lesions. Attenuation coefficients at CT correlated inversely with FDG (reader 1: r = -0.3007; P < .001; reader 2: r = -0.3147; P < .001) and FDHT (reader 1: r = -0.2680; P = .001; reader 2: r = -0.3656; P < .001) uptake. The number of lesions on CT scans was significantly associated with overall survival (reader 1: hazard ratio [HR], 1.025; P = .05; reader 2: HR, 1.021; P = .04). The numbers of lesions on FDG and FDHT PET scans were significantly associated with overall survival for reader 1 (HR, 1.051-1.109; P < .001) and reader 2 (HR, 1.026-1.082; P ≤ .009). Patients with higher FDHT uptake (lesion with the highest maximum standardized uptake value) had significantly shorter overall survival (reader 1: HR, 1.078; P = .02; reader 2: HR, 1.092; P = .02). FDG uptake intensity was not associated with overall survival (reader 1, P = .65; reader 2, P = .38). CONCLUSION/CONCLUSIONS:In patients with castration-resistant prostate cancer, numbers of bone lesions on CT, FDG PET, and FDHT PET scans and the intensity of FDHT uptake are significantly associated with overall survival.

PURPOSE/OBJECTIVE:To evaluate the relationship between prostate cancer aggressiveness and histogram-derived apparent diffusion coefficient (ADC) parameters obtained from whole-lesion assessment of diffusion-weighted magnetic resonance (MR) imaging of the prostate and to determine which ADC metric may help best differentiate low-grade from intermediate- or high-grade prostate cancer lesions. MATERIALS AND METHODS/METHODS:The institutional review board approved this retrospective HIPAA-compliant study of 131 men (median age, 60 years) who underwent diffusion-weighted MR imaging before prostatectomy for prostate cancer. Clinically significant tumors (tumor volume > 0.5 mL) were identified at whole-mount step-section histopathologic examination, and Gleason scores of the tumors were recorded. A volume of interest was drawn around each significant tumor on ADC maps. The mean, median, and 10th and 25th percentile ADCs were determined from the whole-lesion histogram and correlated with the Gleason score by using the Spearman correlation coefficient (ρ). The ability of each parameter to help differentiate tumors with a Gleason score of 6 from those with a Gleason score of at least 7 was assessed by using the area under the receiver operating characteristic curve (Az). RESULTS:In total, 116 clinically significant lesions (89 in the peripheral zone, 27 in the transition zone) were identified in 85 of the 131 patients (65%). Forty-six patients did not have a clinically significant lesion. For mean ADC, median ADC, 10th percentile ADC, and 25th percentile ADC, the Spearman ρ values for correlation with Gleason score were -0.31, -0.30, -0.36, and -0.35, respectively, whereas the Az values for differentiating lesions with a Gleason score of 6 from those with a Gleason score of at least 7 were 0.704, 0.692, 0.758, and 0.723, respectively. The Az of 10th percentile ADC was significantly higher than that of the mean ADC for all lesions and peripheral zone lesions (P = .0001). CONCLUSION/CONCLUSIONS:When whole-lesion histograms were used to derive ADC parameters, 10th percentile ADC correlated with Gleason score better than did other ADC parameters, suggesting that 10th percentile ADC may prove to be optimal for differentiating low-grade from intermediate- or high-grade prostate cancer with diffusion-weighted MR imaging.

Many common PET segmentation methods for malignant lesions use surrounding background activity as a reference. To date, background has to be measured by drawing a second volume of interest (VOI) in nearby, undiseased tissue. This is time consuming as two VOIs have to be determined for each lesion. The aim of our study was to analyse whether background activity in different organs and body regions could be calculated from the tumour VOI by histogram analyses. The institutional review board waived informed consent for this retrospective study. For each of the following tumour types and areas - head and neck (neck), lung, hepatic metastasis (liver), melanoma (skin), and cervix (pelvis) - 10 consecutive patients with biopsy-proven tumours who underwent (18)F-fluorodeoxyglucose-PET in January 2012 were retrospectively selected. One lesion was selected and two readers drew a cubical VOI around the lesion (VOItumour) and over the background (VOIBG). The mean value of VOIBG was compared with the mode of the histogram, using equivalence testing with an equivalence margin of ±0.5 SUV. Inter-reader agreement was analysed for the mean background, and the mode of the VOItumour histogram was assessed using the concordance correlation coefficient. For both readers, the mode of VOItumour was equivalent to the mean of VOIBG (P<0.0001 for R1 and R2). The inter-reader agreement was almost perfect, with a concordance correlation coefficient of greater than 0.92 for both the mode of VOItumour and the mean of VOIBG. Background activity determined within a tumour VOI using histogram analysis is equivalent to separately measured mean background values, with an almost perfect inter-reader agreement. This could facilitate PET quantification methods based on background values without increasing workload.