Faculty Bibliography

OBJECTIVE: To assess recent national specialty trends in the use of diagnostic ultrasound (US) services in the Emergency Department (ED) setting. METHODS: We searched aggregated 1998-2012 Medicare Part B Master Files for ED diagnostic US studies, excluding cardiac and ophthalmic examinations. Studies were classified by body part and interpreting specialty. Subsequent analysis was performed for higher-volume services rendered by emergency physicians for which discrete codes were present longitudinally for complete vs limited examinations. National trends were analyzed. RESULTS: From 1998 to 2012, paid ED US studies interpreted by radiologists, emergency physicians, and all other physicians increased by 332% (from 221 712 to 735 858 examinations), 4454% (from 561 to 24 992), and 251% (from 26 961 to 67 787), respectively. The fraction of ED US examinations interpreted remained around 90% for radiologists, increased from 0.2% to 3% for emergency physicians, and decreased from 11% to 8% for other physicians. The fraction of complete abdominal and complete retroperitoneal studies interpreted by emergency physicians remained less than 1% from 1998 through 2012. However, emergency physicians experienced disproportionate growth in limited examinations (from 1% to 9% for abdominal studies and from <1% to 20% for retroperitoneal studies). Likewise, the fraction of (typically targeted) chest studies interpreted by emergency physicians increased from less than 1% to 63%. CONCLUSION: From 1998 to 2012, there was substantial growth in ED US studies for Medicare beneficiaries interpreted by radiologists and emergency physicians alike. For more commonly performed services distinguishable as complete vs limited in nature, growth in services by emergency physicians was most dramatic for less complex services.

PURPOSE: The aim of this report is to describe our early experience with radiologist-led direct public education about imaging-based cancer screening examinations, with a focus on the level of satisfaction and the educational impact reported by session participants. METHODS: Subspecialty radiologists provided 1-hour educational sessions to small lay public audiences covering breast, prostate, and lung cancer screening, focusing on key radiologic screening tests. Subsequently, session participants completed a survey pertaining to their levels of satisfaction and the perceived impact of the sessions on knowledge of the diseases and relevant screening tests; results from all topic sessions were pooled for analysis. RESULTS: One hundred nineteen participants attended a total of 144 sessions. The large majority of respondents agreed or strongly agreed that the sessions increased their understanding (95.4%), they gained information not obtained from clinic visit (88.1%), seeing radiology images helped their understanding (92.6%), they felt more involved in their own care (85.8%), they felt more prepared to undergo screening tests (87.4%), they were satisfied with the sessions' format (93.3%) and content (96.2%), their main questions were answered (88.3%), they would be interested in similar future radiologist-led sessions (88.5%), and they would recommend the sessions to friends (93.9%). The provided information (43.1%) and images (34.7%) were identified as the most helpful aspects of the sessions. CONCLUSION: Radiologist-led direct public education sessions about imaging-based cancer screening examinations yield high levels of audience satisfaction and add value to the public's understanding of the role of radiology and radiologists. Our experience may provide an encouraging model for other radiology practices in pursuing similar endeavors.

AIM: To compare the size and shape of the prostate between in-vivo and fresh ex-vivo magnetic resonance imaging (MRI), in order to quantify alterations in the prostate resulting from surgical resection. MATERIAL AND METHOD: Ten patients who had undergone 3 T prostate MRI using a phased-array coil and who were scheduled for prostatectomy were included in this prospective study. The ex-vivo specimen underwent MRI prior to formalin fixation or any other histopathological processing. Prostate volume in vivo and ex vivo was assessed using planimetry. Prostate shape was assessed by calculating ratios between the diameters of the prostate in all three dimensions. RESULTS: Mean prostate volume was significantly smaller ex vivo than in vivo (39.7 +/- 18.6 versus 50.8 +/- 26.8 cm3; p = 0.008), with an average change in volume of -19.5%. The right-to-left (RL)/anteroposterior (AP) ratio of the prostate, representing the shape of the prostate within its axial plane, was significantly larger ex vivo than in vivo (1.33 +/- 0.14 versus 1.21 +/- 0.12; p = 0.015), with an average percent change in RL/AP ratio of the prostate of +12.2%. There was no significant difference between in-vivo and ex-vivo acquisitions in terms of craniocaudal (CC)/AP (p = 0.963, median change = -2.1%) or RL/CC (p = 0.265, median change = +1.3%) ratios. CONCLUSION: The observed volume and shape change following resection has not previously been assessed by comparison of in-vivo and fresh ex-vivo MRI and likely represents loss of vascularity and of connective tissue attachments in the ex-vivo state. These findings have implications for co-registration platforms under development to facilitate improved understanding of the accuracy of MRI in spatial localization of prostate tumours.

INTRODUCTION: To compare qualitative and quantitative imaging features from conventional and diffusion-weighted (DW) magnetic resonance imaging (MRI) in detection of metastatic pelvic lymph nodes in bladder cancer patients undergoing cystectomy. MATERIALS AND METHODS: Thirty-six patients who had undergone cystectomy for bladder cancer with preoperative MRI with DWI sequence prior to surgery were included. Imaging features on conventional and DW-MRI were compared with histopathology at cystectomy. RESULTS: Nodal features associated with metastatic lymphadenopathy were short axis (AUC = 0.85, p < 0.001; when SA > 5 mm: sensitivity = 88%, specificity = 75%), long axis (AUC = 0.80, p < 0.001; when LA > 6 mm: sensitivity = 88%, specificity = 71%), apparent diffusion coefficient (ADC) on DWI, normalized to muscle (AUC = 0.66, p = 0.113; when nADC < 1.35: sensitivity = 75%, specificity = 68%), and absence of fatty hilum on conventional imaging (AUC = 0.73, p = 0.012; when fatty hilum absent, sensitivity = 75%, specificity = 71%). ADC without normalization was not associated with metastasis (p = 0.303). CONCLUSIONS: Imaging findings from conventional MRI and DWI achieved reasonable accuracy for detecting metastatic lymph nodes in bladder cancer, although sensitivity was higher than specificity. A short axis greater than 5 mm on conventional MRI had the highest accuracy of any individual finding. When using DWI, normalization of ADC values to muscle ADC may improve diagnostic performance.

Introduction and Objectives: With improving accuracy of prostate cancer detection and localization using multi-parametric MRI (mpMRI), there is an increasing interest in mpMRI guidance of diagnosis and surveillance biopsy. Widespread application of such concept must address the challenging issues, including the ability to perform MRI-guided biopsy in realtime with adequate accuracy, and in the simple urology office environment. We propose and assess a new approach a new approach to directly coregister 2D standard TRUS to MRI. Materials and Methods: The developed concept is to use a raw 2D Ultrasound (US) (B&K 8848 device) prostate image and register it to the corresponding MRI slice. Pre-acquired MRI data represents the whole gland in 3D as an ordered collection of 2D MRI slices of known thickness. We have developed software for USMRI coregistration based on image intensity, texture, and boundaries. The power parameter P is directly proportional to algorithm speed and accuracy. The result is source US overlaying target MRI for visualization. The system was prospectively tested on 8 data sets corresponding to US images matching with prostate MRI. These data come from patients who underwent MRI prior to biopsy. Coregistration results were evaluated as success/failure by an expert urologist who interactively adjusted the transparency of US-MRI overlays and recorded the alignment of anatomical landmarks in both modalities, especially the veru montanum. Results: The system was able to find the matching slice of T2WI for all single 2D standard US slice. In all cases the location of the veru montanum confirmed the coregistration accuracy in axial plan. The median rank of the T2WI slice was the fifth one among median number of 10 T2WI slices. We tested the power parameter P=1; P=5 and P=20. Twenty three coregistrations over 23 were correct. There was a significant positive correlation between prostate volume and time of computation for each P value. The image similarity reached a 0.93 mean Dice index u!

Introduction and Objectives: Focal therapy (FT) is an emerging approach for treatment of localized prostate cancer. Multi-parametric (mp) MRI demonstrated capability to monitor the effect of FT procedures. At time of followup, the ablated zone (AZ) clearly undergoes local shrinkage. Accurate definition of AZ at follow-up will improve FT evaluation and oncologic safety. We analyzed the volume and shape changes of the gland between pre and post FT MRI by developing a 3D coregistration method to compensate for deformation of the gland in response to FT. Materials and Methods: We studied 10 patients who underwent FT (interstitial laser ablation and photodynamic therapy) within IRB approved trials. All patients underwent preoperative, early control and late postoperative 3T MRI which included T2, T1, diffusion and perfusion weighted sequences. We have developed image registration software to analyze, transfer and model shape changes using a deformable and a rigid body transformation. Alignment between pre- and post-op images of AZ was assessed using the overlap index or Dice index (Di) and the maximum boundary distance, or Hausdorff distance (HD). Correction for deformation was measured using the HD normalized by the volume to transform in mm/ cc and automated feature of the software. Results: There was a significant volume decrease D of the gland that averaged 6.49 cc (p=0.017) between preoperative and postoperative gland. D was directly correlated (=0.738, p=0.014) with the ablated volume (7.88, p=0.04). We successfully co registered pre operative to post operative MRI in each cases. There was a significant increase D computed with deformable versus rigid transform. Deformable model achieved a significantly more accurate match of pre- vs. post-FT AZ with deformable (Di=0.88, HD=1.98 mm) vs. rigid transformation (Di=0.95 HD=3.83mm). The deformable approach also yielded a higher (p=0.019) correction of deformation (0.72mm/cc) compared to the rigid model (0.15mm/cc). Conclusion: We described a novel !

PURPOSE: Optimization of prostate biopsy requires addressing the shortcomings of standard systematic transrectal ultrasound guided biopsy including false negative rates, incorrect risk stratification, detection of clinically insignificant disease, and the need for repetitive biopsy. MRI is an evolving noninvasive imaging modality that increases the accurate localization of prostate cancer (PCa) at the time of biopsy, thereby enhancing clinical risk assessment, and improving the ability to appropriately counsel patients regarding therapy. The purpose of this review is to 1) summarize the various sequences that comprise a prostate multiparametric MRI exam along with its performance characteristics in cancer detection, localization and reporting standards, 2) evaluate potential applications of MRI targeting in prostate biopsy among men with no previous biopsy, a negative previous biopsy, and those with low stage cancer and 3) describe the techniques of MRI-targeted biopsy and their comparative study outcomes MATERIALS AND METHODS: A bibliographic search covering the period up to October, 2013 was conducted using MEDLINE(R)/PubMed(R). Articles were reviewed and categorized based on which of the three objectives of this review was addressed. Data was extracted, analyzed, and summarized. RESULTS: Mp-MRI consists of anatomic T2-weighted imaging coupled with at least 2 functional imaging techniques and has demonstrated improved PCa detection sensitivity up to 80% in the peripheral zone and 81% in the transition zone. A PCa MRI suspicion score has been developed and is depicted using the Likert or PI-RADS scale for better standardization of MRI interpretation and reporting. Among men with no previous biopsy, MRI increases the frequency of significant cancer detection to 50% in low risk and 71% in high risk patients. In low risk men, the negative predictive valve of a combination of negative MRI with prostate volume parameters is nearly 98%, suggesting a potential role in avoiding a biopsy and reducing overdetection/overtreatment. Among men with previous negative biopsy, 72-87% of cancers detected by MRI guidance are clinically significant. Among men with known low risk cancer, repeat biopsy by MR-targeting demonstrates a high likelihood of confirming low risk disease in low suspicion score lesions and for upgrading in high suspicion score lesions. Techniques of MRI-targeted biopsy include visual estimation TRUS-guided biopsy, software co-registered MRI-US TRUS-guided biopsy, and in-bore MRI-guided biopsy. Although the improvement in accuracy and efficiency of visual estimation biopsy compared to systematic appears limited, both co-registered MRI-US biopsy and in-bore MRI-guided biopsy appears to increase cancer detection rates in conjunction with increasing suspicion score. CONCLUSIONS: Use of MRI for targeting prostate biopsies has potential to reduce the sampling error associate with conventional biopsy by providing better disease localization and sampling. More accurate risk stratification through improved cancer sampling may impact upon therapeutic decision-making. Optimal clinical application of MRI-targeted biopsy remains under investigation.

BACKGROUND: Increasing evidence supports the use of magnetic resonance (MR)-targeted prostate biopsy. The optimal method for such biopsy remains undefined, however. OBJECTIVE: To prospectively compare targeted biopsy outcomes between MR imaging (MRI)-ultrasound fusion and visual targeting. DESIGN, SETTING, AND PARTICIPANTS: From June 2012 to March 2013, prospective targeted biopsy was performed in 125 consecutive men with suspicious regions identified on prebiopsy 3-T MRI consisting of T2-weighted, diffusion-weighted, and dynamic-contrast enhanced sequences. INTERVENTION: Two MRI-ultrasound fusion targeted cores per target were performed by one operator using the ei-Nav|Artemis system. Targets were then blinded, and a second operator took two visually targeted cores and a 12-core biopsy. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Biopsy information yield was compared between targeting techniques and to 12-core biopsy. Results were analyzed using the McNemar test. Multivariate analysis was performed using binomial logistic regression. RESULTS AND LIMITATIONS: Among 172 targets, fusion biopsy detected 55 (32.0%) cancers and 35 (20.3%) Gleason sum >/=7 cancers compared with 46 (26.7%) and 26 (15.1%), respectively, using visual targeting (p=0.1374, p=0.0523). Fusion biopsy provided informative nonbenign histology in 77 targets compared with 60 by visual (p=0.0104). Targeted biopsy detected 75.0% of all clinically significant cancers and 86.4% of Gleason sum >/=7 cancers detected on standard biopsy. On multivariate analysis, fusion performed best among smaller targets. The study is limited by lack of comparison with whole-gland specimens and sample size. Furthermore, cancer detection on visual targeting is likely higher than in community settings, where experience with this technique may be limited. CONCLUSIONS: Fusion biopsy was more often histologically informative than visual targeting but did not increase cancer detection. A trend toward increased detection with fusion biopsy was observed across all study subsets, suggesting a need for a larger study size. Fusion targeting improved accuracy for smaller lesions. Its use may reduce the learning curve necessary for visual targeting and improve community adoption of MR-targeted biopsy.

A modified Gleason grading system as proposed in the 2005 International Society of Urological Pathology (ISUP) consensus meeting is the current grading system for prostate cancer. With this modified ISUP Gleason grading system, many Gleason score (GS) 6 cancers by the old grading system are upgraded to GS7 cancers on biopsy diagnosis even with minimal quantity (