Adam T. Froemming

Detection of Recurrent Prostate Cancer After Radical Prostatectomy: Comparison of 11C-Choline PET/CT with Pelvic Multiparametric MR Imaging with Endorectal Coil

The aim of this study was to compare 11C-choline PET/CT with pelvic multiparametric MR imaging for detection of recurrent prostate carcinoma in patients with suspected recurrence after radical prostatectomy and to identify an optimal imaging method to restage these patients. Methods: This was a retrospective, single-institution study of 115 prostatectomy patients with suspected tumor recurrence who underwent both 11C-choline PET/CT and multiparametric MR imaging with endorectal coil. The reference standard included histopathology, treatment change, and imaging follow-up for determination of locally recurrent tumor, lymph node (LN) metastases, and skeletal metastases. Two nuclear medicine and 2 genitourinary radiologists independently and in a masked manner reviewed PET/CT and multiparametric MR imaging, respectively. The reviewers assessed for local recurrence in the prostatectomy bed as well as LN and bone metastases, rating their diagnostic confidence with a 5-point scoring system for each location. Receiver-operating-characteristic analysis was used to compare the 2 modalities. Results: The standard of reference (either positive or negative) for the diagnosis of local recurrence and pelvic LN and bone metastases was met in 87, 70, and 95 patients, respectively. Documented local recurrence and pelvic LN and bone metastases was present in 61 of 87 (70.1%), 50 of 70 (71.4%), and 16 of 95 (16.8%) patients, respectively. Patient-based area under the receiver-operating-characteristic curves of multiparametric MR imaging versus PET/CT for the diagnosis of local recurrence and pelvic LN and bone metastases were 0.909 versus 0.761 (P = 0.0079), 0.812 versus 0.952 (P = 0.0064), and 0.927 versus 0.898 (P = 0.69), respectively. Among 61 patients with local recurrence, 32 patients (52.4%) were correctly diagnosed as having local recurrence by both multiparametric MR imaging and PET/CT, 22 (36.1%) were correctly diagnosed by multiparametric MR imaging only, 6 (9.8%) could not be diagnosed by either modality, and 1 (1.6%) was correctly diagnosed by PET/CT only. The patient-based sensitivity, specificity, and accuracy of multiparametric MR imaging for diagnosing local recurrence were 88.5% (54/61), 84.6% (22/26), and 87.4% (76/87) whereas those of PET/CT for detecting body LN or bone metastases were 92.3% (72/78), 100% (18/18), and 93.8% (90/96), respectively. Conclusion: Multiparametric MR imaging with endorectal coil is superior for the detection of local recurrence, PET/CT is superior for pelvic LN metastasis, and both were equally excellent for pelvic bone metastasis. 11C-choline PET/CT and pelvic multiparametric MR imaging are complementary for restaging prostatectomy patients with suspected recurrent disease.

Interobserver Reproducibility of the PI-RADS Version 2 Lexicon: A Multicenter Study of Six Experienced Prostate Radiologists

Purpose To determine the interobserver reproducibility of the Prostate Imaging Reporting and Data System (PI-RADS) version 2 lexicon. Materials and Methods This retrospective HIPAA-compliant study was institutional review board-approved. Six radiologists from six separate institutions, all experienced in prostate magnetic resonance (MR) imaging, assessed prostate MR imaging examinations performed at a single center by using the PI-RADS lexicon. Readers were provided screen captures that denoted the location of one specific lesion per case. Analysis entailed two sessions (40 and 80 examinations per session) and an intersession training period for individualized feedback and group discussion. Percent agreement (fraction of pairwise reader combinations with concordant readings) was compared between sessions. κ coefficients were computed. Results No substantial difference in interobserver agreement was observed between sessions, and the sessions were subsequently pooled. Agreement for PI-RADS score of 4 or greater was 0.593 in peripheral zone (PZ) and 0.509 in transition zone (TZ). In PZ, reproducibility was moderate to substantial for features related to diffusion-weighted imaging (κ = 0.535-0.619); fair to moderate for features related to dynamic contrast material-enhanced (DCE) imaging (κ = 0.266-0.439); and fair for definite extraprostatic extension on T2-weighted images (κ = 0.289). In TZ, reproducibility for features related to lesion texture and margins on T2-weighted images ranged from 0.136 (moderately hypointense) to 0.529 (encapsulation). Among 63 lesions that underwent targeted biopsy, classification as PI-RADS score of 4 or greater by a majority of readers yielded tumor with a Gleason score of 3+4 or greater in 45.9% (17 of 37), without missing any tumor with a Gleason score of 3+4 or greater. Conclusion Experienced radiologists achieved moderate reproducibility for PI-RADS version 2, and neither required nor benefitted from a training session. Agreement tended to be better in PZ than TZ, although was weak for DCE in PZ. The findings may help guide future PI-RADS lexicon updates. (©) RSNA, 2016 Online supplemental material is available for this article.

Renal Epithelioid Angiomyolipoma: Imaging Characteristics in Nine Cases With Radiologic-Pathologic Correlation and Review of the Literature

OBJECTIVE The purpose of this study was to describe the imaging features of renal epithelioid angiomyolipoma (EAML), a rare subtype of angiomyolipoma, with clinical and pathologic correlation. MATERIALS AND METHODS This study was a retrospective review of nine cases from a single institution in which total resection and preoperative imaging were performed and the diagnosis of EAML was made. Imaging included CT (nine cases), MRI (five cases), and ultrasound (one case), and the images were reviewed in consensus by two radiologists. Patient demographics, disease associations, presentation, and outcomes were determined by chart review. RESULTS The patients were nine women and one man (mean age, 42 years). Two patients had tuberous sclerosis complex. The size of the nine EAMLs ranged from 1.4 to 22 cm (mean, 7.8 cm). Six lesions had minor components of fat identifiable at imaging. The contrast enhancement pattern was heterogeneous in eight lesions, five of which contained cysts, necrosis, and hematoma. Four presentations were acute hemorrhage, with ruptured EAML in three of the four. Five tumors extended into the renal sinus. Two tumors were locally invasive. One patient had metastatic disease at presentation with epithelioid tumor identified in a single lymph node. The follow-up periods ranged from 0 to 89 months, and there was one case of suspected but not yet proved recurrence. CONCLUSION Renal EAML can have a range of imaging appearances and can be indistinguishable from renal cell carcinoma and angiomyolipoma with minimal fat. EAML can be considered when a mass is found that has small foci of macroscopic fat without calcification or when acute hemorrhage of a renal mass occurs.

The Incremental Role of Magnetic Resonance Imaging for Prostate Cancer Staging before Radical Prostatectomy

In the present report we aimed to analyze the incremental value of preoperative magnetic resonance imaging (MRI), in addition to clinical variables and clinically-derived nomograms, in predicting outcomes radical prostatectomy (RP). All Mayo Clinic RP patients who underwent preoperative 1.5-Tesla MRI with endo-rectal coil from 2003 to 2013 were identified. Clinical and histopathological variables were used to calculate Partin estimates and Cancer of the Prostate Risk Assessment (CAPRA) score. MRI results in terms of extracapsular extension (ECE), seminal vesicle invasion (SVI), and lymph-node invasion (N+) were recorded. Using RP pathology as gold standard, we developed multivariate logistic regression models based on clinical variables, Partin Tables, and CAPRA score, and assessed their predictive accuracy before and after the addition of MRI results. Five hundred and one patients were included. MRI + clinical models outperformed clinical-based models alone for all outcomes. Comparing Partin and Partin + MRI predictive models, the areas under the curve were 0.61 versus 0.73 for ECE, 0.75 versus 0.82 for SVI, and 0.82 versus 0.85 for N+. Comparing CAPRA and CAPRA + MRI models, the areas under the curve were 0.69 versus 0.77 for ECE, 0.75 versus 0.83 for SVI, and 0.82 versus 0.85 for N+. Our data show that MRI can improve clinical-based models in prediction of nonorgan confined disease, particularly for ECE and SVI. PATIENT SUMMARY Magnetic resonance imaging, together with clinical information, can be useful in preoperative assessment before radical prostatectomy.

Contemporary Mapping of Post-Prostatectomy Prostate Cancer Relapse with 11C-Choline Positron Emission Tomography and Multiparametric Magnetic Resonance Imaging

Purpose: We identify sites and patterns of cancer recurrence in patients with post‐prostatectomy biochemical relapse using 11C‐choline positron emission tomography/computerized tomography and endorectal coil multiparametric magnetic resonance imaging. Materials and Methods: Between January 2008 and June 2015, 2,466 men underwent choline positron emission tomography for suspected prostate cancer relapse at our institution. Of these men 202 did not receive hormone or radiation therapy, underwent imaging with choline positron emission tomography and multiparametric magnetic resonance imaging, and were found to have disease recurrence. Overall patterns of recurrence were described, and factors associated with local only recurrence were evaluated using univariable and multivariable logistic regression. Results: Median prostate specific antigen at positive scan was 2.3 ng/ml (IQR 1.4–5.5) with a median time from prostate specific antigen relapse to lesion visualization of 15 months (IQR 4.8–34.2). Of these 202 men 68 (33%) exhibited local only, 45 (22%) local plus metastatic and 89 (45%) metastatic only relapse. Pelvic node only relapse was observed in 39 (19%) men. Median prostate specific antigen at positive imaging for patients with local only, metastatic only and local plus metastatic relapse was 2.3, 2.7 and 2.2 ng/ml (p=0.46), with a median interval from biochemical recurrence to positive scan of 33.5, 7.0 and 15.0 months, respectively (p <0.001). On multivariable analysis time from biochemical recurrence to positive imaging was independently associated with local only recurrence (OR 1.10 for every 6‐month increase, p=0.012). Conclusions: Combined choline positron emission tomography and multiparametric magnetic resonance imaging evaluation of biochemical recurrence after prostatectomy reveals an anatomically diverse pattern of recurrence. These findings have implications for optimizing the salvage treatment of patients with prostate cancer with relapse following surgery.

Probe Retraction during Renal Tumor Cryoablation: A Technique to Minimize Direct Ureteral Injury

Ureteral injury is a well-known complication of radiofrequency ablation of renal tumors. Ureteral injury with cryoablation seems to be less common, but has been reported. Herein, the authors describe a technique that can be used to avoid direct ureteral injury during cryoablation of renal masses. Initial ice ball formation serves to fix the probe in the target. The mass and kidney can then be retracted away from the ureter to avoid direct involvement with the subsequent ice ball. The authors report three successful example cases, with no significant complications.

Detection of Local Recurrence of Prostate Cancer After Radical Prostatectomy Using Endorectal Coil MRI at 3 T: Addition of DWI and Dynamic Contrast Enhancement to T2-Weighted MRI

OBJECTIVE The purpose of this study was to assess the utility of DWI and dynamic contrast enhancement (DCE) in MRI at 3 T with an endorectal coil in identifying local prostate cancer recurrence after radical prostatectomy. MATERIALS AND METHODS Eighty men underwent MRI for suspected local recurrence. The reference standards were histopathologic result, decrease in prostate-specific antigen level after salvage radiation therapy, and follow-up findings. Using a 5-point scoring system, two reviewers independently interpreted T2-weighted images alone (protocol A), a combination of T2-weighted and DW images (protocol B), a combination of T2-weighted and DCE images (protocol C), and a combination of T2-weighted, DW, and DCE images (protocol D). ROC analysis was used to compare the four protocols. RESULTS Local recurrence was found in 57 of the 80 patients (71.3%). The ROC AUCs for protocols A, B, C, and D were 0.71, 0.72, 0.90, and 0.89 for reader 1 and 0.65, 0.62, 0.84, and 0.83 for reader 2. Protocols C and D had statistically better performance than protocols A and B for both readers (p < 0.001). For local recurrence lesions with a long-axis diameter less than 10 mm visualized with protocol C, protocol B had detection rates of 25.0-29.4% and for lesions measuring 10 mm or greater, 67.9-69.0%. The rates of detection of local recurrence with protocol C or D were 76.5-82.4% for prostate-specific antigen levels less than 0.4 ng/mL, 60-73.3% for 0.4-1.0 ng/mL, and 80-88.0% for greater than 1.0 ng/mL. CONCLUSION Addition of DCE to T2-weighted imaging in 3-T MRI with an endorectal coil improves the accuracy of detection of local cancer recurrence after radical prostatectomy. The addition of DWI is of limited incremental value for detection, especially of small lesions.

Individualized kV selection and tube current reduction in excretory phase computed tomography urography: potential for radiation dose reduction and the contribution of iterative reconstruction to image quality.

Objective The objective of this study was to analyze radiation dose reduction and image quality by combining automated kV selection, tube current reduction, and iterative reconstruction. Methods This was a retrospective analysis of the excretory phase of 55 patients with 2 computed tomography urography examinations: automated kV selection with tube current reduction (“low-dose protocol”: with filtered back projection vs iterative reconstruction) and routine dose examinations. Image quality was analyzed blindly and in side-by-side analyses, in addition to quantitative measurements. Results Low-dose protocol median dose change was −40% (−10.7 to +12.9 mGy); 100 kV was autoselected in 44 (80%) of 55 patients (body mass index range, 19–36 kg/m2) with mean dose reduction of 42.5%. Whereas up to 19% of low-dose images with filtered back projection were inferior by blinded review (P < 0.001), low-dose iterative reconstruction images were not rated inferior (P = 1.0). Conclusions The combination of iterative reconstruction, automated kV selection, and tube current reduction results in radiation dose reduction with preserved image quality and diagnostic confidence.

How and why a generation of radiologists must be trained to accurately interpret prostate mpMRI.

be trained to accurately interpret prostate mpMRI Rajan T. Gupta, Benjamin Spilseth, Adam T. Froemming Department of Radiology, Duke University Medical Center, DUMC, Box 3808, Durham, NC 27710, USA Duke Cancer Institute, DUMC, Box 3494, 20 Duke Medicine Circle, Durham, NC 27710, USA Department of Radiology, University of Minnesota Medical Center, MMC 292, 420 East Delaware Street, Minneapolis, MN 55455, USA Department of Radiology, Mayo Clinic, 200 First St. SW, Rochester, MN 55905, USA

Adenocarcinoma in situ, minimally invasive adenocarcinoma, and invasive pulmonary adenocarcinoma--analysis of interobserver agreement, survival, radiographic characteristics, and gross pathology in 296 nodules.

The International Association for the Study of Lung Cancer/American Thoracic Society/European Respiratory Society and 2015 World Health Organization classifications of lung adenocarcinoma recommend designating tumors showing entirely lepidic growth as adenocarcinoma in situ (AIS) and lepidic tumors with invasion less than or equal to 5 mm as minimally invasive adenocarcinoma (MIA), both of which have superior outcome to conventional invasive adenocarcinoma (IA). Data on interobserver variability within this classification are limited, and further validation of the superior survival of AIS and MIA is needed. A total of 296 surgically excised pulmonary adenocarcinomas were reviewed from 254 patients (1997-2009). Slides were independently reviewed by 2 pulmonary pathologists who categorized tumors as AIS, MIA, or IA. Of 296 nodules, 244 (82.4%) were agreed upon by both observers: 10 AIS, 61 MIA, and 173 IA (κ = 0.63, good agreement). In 6 cases (2%), there was disagreement between AIS and MIA; in 45 cases (15%), there was disagreement between MIA and IA; and in 1 case, there was disagreement between AIS and IA. Overall survival was significantly different among categories as determined by both observers. Cases with disagreement between MIA and IA had similar survival to agreed MIA. Disease-specific 10-year survival was 100% for AIS (both observers) and 97.3% and 97.6% for MIA, although this did not reach statistical significance compared to IA for either observer. Good agreement was present between observers when classifying tumors as AIS, MIA, and IA. Significant differences in overall survival were present between the 3 groups for both observers, and interobserver variability was evident. Patients with AIS and MIA experienced excellent DSS.