Faculty Bibliography

OBJECTIVE:Postoperative imaging after surgery for anterior glenohumeral instability poses a great challenge, which can be compounded by a lack of familiarity with the many different operative techniques and their expected normal appearances and complications. In this article, we discuss the postoperative imaging appearances of anterior glenohumeral instability surgery with a review of currently recommended treatment guidelines. CONCLUSION/CONCLUSIONS:It is important for radiologists to accurately detect complications of anterior shoulder instability surgery at postoperative imaging.

OBJECTIVE:The aim of this article is to review the postoperative MRI appearances of irreparable massive rotator cuff tears (RCTs) after surgery was performed using newer techniques, including patch repair, muscle tendon transfer, superior capsular reconstruction, and subacromial balloon implantation. CONCLUSION/CONCLUSIONS:Newer surgical techniques are emerging for the management of massive RCTs. As radiologists become increasingly likely to encounter postoperative imaging studies of RCTs repaired using these techniques, familiarity with the normal postoperative appearances and complications associated with these techniques becomes important.

OBJECTIVE:The purpose of this study was to determine whether adding DWI to conventional MRI of the sacroiliac joints improves the diagnostic performance of MRI readers in the detection of sacroiliitis. MATERIALS AND METHODS/METHODS:values of patients with and those without sacroiliitis were compared. RESULTS:AUC was 0.758 (95% CI, 0.67-0.83). CONCLUSION/CONCLUSIONS:The addition of DWI to conventional MRI does not significantly improve overall diagnostic performance in terms of accuracy, sensitivity, or confidence in the detection of inflammatory sacroiliitis, but it does have increased specificity and interobserver agreement. ADC threshold values can be used as predictors of sacroiliitis but give no added advantage over MRI with DWI.

BACKGROUND:Metastatic biopsies are increasingly being performed in patients with advanced prostate cancer to search for actionable targets and/or to identify emerging resistance mechanisms. Due to a predominance of bone metastases and their sclerotic nature, obtaining sufficient tissue for clinical and genomic studies is challenging. METHODS:Patients with prostate cancer bone metastases were enrolled between February 2013 and March 2017 on an institutional review board-approved protocol for prospective image-guided bone biopsy. Bone biopsies and blood clots were collected fresh. Compact bone was subjected to formalin with a decalcifying agent for diagnosis; bone marrow and blood clots were frozen in optimum cutting temperature formulation for next-generation sequencing. Frozen slides were cut from optimum cutting temperature cryomolds and evaluated for tumor histology and purity. Tissue was macrodissected for DNA and RNA extraction, and whole-exome sequencing and RNA sequencing were performed. RESULTS:Seventy bone biopsies from 64 patients were performed. Diagnostic material confirming prostate cancer was successful in 60 of 70 cases (85.7%). The median DNA/RNA yield was 25.5 ng/μL and 16.2 ng/μL, respectively. Whole-exome sequencing was performed successfully in 49 of 60 cases (81.7%), with additional RNA sequencing performed in 20 of 60 cases (33.3%). Recurrent alterations were as expected, including those involving the AR, PTEN, TP53, BRCA2, and SPOP genes. CONCLUSIONS:This prostate cancer bone biopsy protocol ensures a valuable source for high-quality DNA and RNA for tumor sequencing and may be used to detect actionable alterations and resistance mechanisms in patients with bone metastases. Cancer 2017. © 2017 American Cancer Society.

PURPOSE: To compare diagnostic performance of a 5-min knee MRI protocol to that of a standard knee MRI. MATERIALS AND METHODS: One hundred 3 T (100 patients, mean 38.8 years) and 50 1.5 T (46 patients, mean 46.4 years) MRIs, consisting of 5 fast, 2D multi-planar fast-spin-echo (FSE) sequences and five standard multiplanar FSE sequences, from two academic centers (1/2015-1/2016), were retrospectively reviewed by four musculoskeletal radiologists. Agreement between fast and standard (interprotocol agreement) and between standard (intraprotocol agreement) readings for meniscal, ligamentous, chondral, and bone pathology was compared for interchangeability. Frequency of major findings, sensitivity, and specificity was also tested for each protocol. RESULTS: Interprotocol agreement using fast MRI was similar to intraprotocol agreement with standard MRI (83.0-99.5%), with no excess disagreement (/= 0.215), except more ACL tears on fast MRI (p = 0.021) and more cartilage defects on standard MRI (p < 0.001). Sensitivities (59-100%) and specificities (73-99%) of fast and standard MRI were not significantly different for meniscal and ligament tears (95% CI for difference, -0.08-0.08). For cartilage defects, fast MRI was slightly less sensitive (95% CI for difference, -0.125 to -0.01) but slightly more specific (95% CI for difference, 0.01-0.5) than standard MRI. CONCLUSION: A fast 5-min MRI protocol is interchangeable with and has similar accuracy to a standard knee MRI for evaluating internal derangement of the knee.

Diagnosis and treatment of foot disease in patients with diabetes is a common clinical-radiologic challenge, particularly the differentiation of neuropathic arthropathy from osteomyelitis. Conventional clinical tests and imaging techniques have limited accuracy for evaluation of the diabetic foot. The introduction of morphologic magnetic resonance (MR) imaging in these patients has provided a qualitative leap in diagnosis. The characteristics of soft-tissue and bone marrow edema and their patterns of distribution throughout the foot allow discrimination between both entities. However, in certain scenarios, the application of MR imaging to this problem is limited because of overlapping features between the two and the coexistence of infection and neuropathic changes. Recent technical advances in MR imaging sequences have increased the capability to add functional quantitative information to structural information. Diffusion-weighted imaging is useful to determine the presence and extension of osteomyelitis. Dynamic contrast-enhanced MR imaging may help to detect differences between the vascularization patterns of neuropathic arthropathy and osteomyelitis. MR angiography (with or without contrast material) is used in clinical practice to identify candidate distal vessels for revascularization. MR neurography, and especially diffusion-tensor imaging, provides quantitative information about neural damage. These new sequences may help in assessment of the different pathophysiologic conditions that occur in the diabetic foot. The physical basis of these techniques, their limitations, and their potential applications for diabetic foot assessment are detailed in this article. The introduction of advanced MR imaging multiparametric protocols, with the aim of enhancing the overall diagnostic accuracy of MR imaging, may help in treatment decision making and lead to improved patient outcomes. (c) RSNA, 2017.

OBJECTIVE: The purpose of this study was to compare the diagnostic performance of a 5-minute shoulder MRI protocol consisting of multiplanar 2D fast spin-echo (FSE) sequences with parallel imaging to that of a standard shoulder MRI protocol. MATERIALS AND METHODS: A retrospective review of 151 3-T MRI examinations of shoulders of 147 patients (mean age, 46.95 years) and 50 1.5-T MRI examinations of shoulders of 50 patients (mean age, 53.74 years) with four fast and five standard sequences from two academic centers between January 2014 and April 2015 was performed by three musculoskeletal radiologists. Interchangeability of fast and standard MRI was tested by comparing interprotocol (fast vs standard) interreader agreement with standard MRI interreader agreement. Interreader agreement was also compared using kappa statistics. The frequency of major findings was compared using an adjusted McNemar test. Sensitivity and specificity of MRI were measured for 51 patients who underwent surgery. RESULTS: Interprotocol reader agreement was essentially equal to reader agreement on standard MRI (mean difference /= 0.08). Sensitivities of fast MRI for tendon and labral tears (33-92%) were equivalent or higher than those of standard MRI with similar specificities (77-98%). CONCLUSION: Fast 5-minute shoulder MRI with multiplanar 2D FSE sequences using parallel imaging is interchangeable, with similar interreader agreement and accuracy, with standard shoulder MRI for evaluating shoulder injuries.

Purpose: The purpose of this study was to determine if a 5-minute knee magnetic resonance imaging (MRI) protocol is interchangeable with a standard knee MRI protocol for evaluation of internal derangement of the knee. Materials and Methods: 100 consecutive patients, in whom a knee MRI was performed for internal derangement between January 2015 and June 2015, were retrospectively reviewed. All patients were scanned on a single 3 T MRI system (Siemens Verio) with a 15- channel knee coil (Siemens). The standard clinical protocol consisting of 6 2-dimensional fast spin echo (2D FSE) sequences without parallel imaging was performed along with 5 additional fast 2D FSE sequences with parallel imaging (acceleration factor = 2). 3 readers (2 musculoskeletal (MSK) radiologists and 1 MSK radiology fellow) independently reviewed the fast and standard images which were anonymized and separated into 2 different reading sets. Readers evaluated for the presence of meniscal and ligament tears, cartilage defects, and bone abnormalities. Frequency of major findings was measured. Interchangeability of fast and standard MRI was tested by comparing the agreement when 1 reader was using fast MRI and the other reader was using standard MRI (interprotocol agreement) with the agreement when both readers were using the standard MRI (intraprotocol agreement). Fast MRI was considered interchangeable if the interprotocol agreement was not less < 5% of the intraprotocol agreement. Results: The study population consisted of 69 males and 31 females with a mean age of 38.8 years (range 18 - 65). The average time for the fast protocol was 4 minutes 8 seconds compared to 17 minutes 20 seconds for the standard protocol. The most common findings reported on MRI as an aggregate of all readers was as follows: medial meniscal tears (46.7%), high grade partial thickness or full thickness cartilage defects (21.9%), lateral meniscal tears (21.3%), and ACL tears (15.7%). The intraprotocol agreement was very similar to the interprotocol agreement for all structures. The intraprotocol and interprotocol agreement were as follows for individual structures, respectively: Medial Mensicus (89.3% vs. 90.0%); Lateral Meniscus (89.3% vs. 89.0%); ACL (96.0% vs. 95.7%); PCL (98.0% vs. 98.3%); MCL (98.0% vs. 98.3%); LCL (98.7% vs. 98.2%); Cartilage (86.3% vs. 86.2%); Fracture/Contusion (90.7% vs. 93.0%); and Marrow Disease (98.0% vs. 98.0%) . The upper bounds of the 95% CIs for the differences between these two proportions were always <5%, suggesting that fast knee MRI can be interchanged with standard MRI without a significant increase in disagreements between readers. Conclusion: A 5-minute knee MRI consisting of multiplanar 2D FSE sequences using parallel imaging is interchangeable with a standard knee MRI for evaluating internal derangement of the knee

BACKGROUND: The purpose of this study was to see if 3-dimensional (3D) magnetic resonance imaging (MRI) could improve our understanding of rotator cuff tendon tear shapes. We believed that 3D MRI would be more accurate than two-dimensional (2D) MRI for classifying tear shapes. METHODS: We performed a retrospective review of MRI studies of patients with arthroscopically proven full-thickness rotator cuff tears. Two orthopedic surgeons reviewed the information for each case, including scope images, and characterized the shape of the cuff tear into crescent, longitudinal, U- or L-shaped longitudinal, and massive type. Two musculoskeletal radiologists reviewed the corresponding MRI studies independently and blind to the arthroscopic findings and characterized the shape on the basis of the tear's retraction and size using 2D MRI. The 3D reconstructions of each cuff tear were reviewed by each radiologist to characterize the shape. Statistical analysis included 95% confidence intervals and intraclass correlation coefficients. RESULTS: The study reviewed 34 patients. The accuracy for differentiating between crescent-shaped, longitudinal, and massive tears using measurements on 2D MRI was 70.6% for reader 1 and 67.6% for reader 2. The accuracy for tear shape characterization into crescent and longitudinal U- or L-shaped using 3D MRI was 97.1% for reader 1 and 82.4% for reader 2. When further characterizing the longitudinal tears as massive or not using 3D MRI, both readers had an accuracy of 76.9% (10 of 13). The overall accuracy of 3D MRI was 82.4% (56 of 68), significantly different (P = .021) from 2D MRI accuracy (64.7%). CONCLUSION: Our study has demonstrated that 3D MR reconstructions of the rotator cuff improve the accuracy of characterizing rotator cuff tear shapes compared with current 2D MRI-based techniques.

OBJECTIVE: This review article explores recent advancements in PET/MRI for clinical oncologic imaging. CONCLUSION: Radiologists should understand the technical considerations that have made PET/MRI feasible within clinical workflows, the role of PET tracers for imaging various molecular targets in oncology, and advantages of hybrid PET/MRI compared with PET/CT. To facilitate this understanding, we discuss clinical examples (including gliomas, breast cancer, bone metastases, prostate cancer, bladder cancer, gynecologic malignancy, and lymphoma) as well as future directions, challenges, and areas for continued technical optimization for PET/MRI.