Anterior Instability: What to Look for
Most first-time anterior glenohumeral dislocations occur as the result of trauma. Many patients suffer recurrent episodes of anterior shoulder instability (ASI). The anatomy and biomechanics of ASI is addressed, as is the pathophysiology of capsulolabral injury. The roles of imaging modalities are described, including computed tomography (CT) and MR imaging with the additional value of arthrography and specialized imaging positions. Advances in 3D CT and MR imaging particularly with respect to the quantification of humeral and glenoid bone loss is discussed. The concepts of engaging and nonengaging lesions as well as on-track and off-track lesions are examined.
MR Imaging of the Shoulder [Editorial]
Musculoskeletal Imaging Applications of Artificial Intelligence
Enhancing communication in radiology using a hybrid computer-human based system
INTRODUCTION/BACKGROUND:Communication and physician burn out are major issues within Radiology. This study is designed to determine the utilization and cost benefit of a hybrid computer/human communication tool to aid in relay of clinically important imaging findings. MATERIAL AND METHODS/METHODS:Analysis of the total number of tickets, (requests for assistance) placed, the type of ticket and the turn-around time was performed. Cost analysis of a hybrid computer/human communication tool over a one-year period was based on human costs as a multiple of the time to close the ticket. Additionally, we surveyed a cohort of radiologists to determine their use of and satisfaction with this system. RESULTS:14,911 tickets were placed in the 6-month period, of which 11,401 (76.4%) were requests to "Get the Referring clinician on the phone." The mean time to resolution (TTR) of these tickets was 35.3 (Â±17.4) minutes. Ninety percent (72/80) of radiologists reported being able to interpret a new imaging study instead of waiting to communicate results for the earlier study, compared to 50% previously. 87.5% of radiologists reported being able to read more cases after this system was introduced. The cost analysis showed a cost savings of up to $101.12 per ticket based on the length of time that the ticket took to close and the total number of placed tickets. CONCLUSIONS:A computer/human communication tool can be translated to significant time savings and potentially increasing productivity of radiologists. Additionally, the system may have a cost savings by freeing the radiologist from tracking down referring clinicians prior to communicating findings.
MRI Assessment of Subspine Impingement: Features beyond the Anterior Inferior Iliac Spine Morphology
Background The MRI manifestations of subspine impingement (SSI) other than morphologic features of anterior inferior iliac spine (AIIS) have not been extensively explored and validated. Purpose To determine the MRI findings associated with SSI, including AIIS morphologic features, femoral distal cam, and associated soft-tissue injuries. Materials and Methods This is a retrospective study of symptomatic patients who underwent arthroscopic treatment for femoroacetabular impingement between December 2014 and March 2017, with preoperative MRI within 6 months before surgery. The SSI group included patients with clinical and intraoperative findings of SSI; the remaining patients comprised the non-SSI group. Preoperative MRI findings were independently assessed by two radiologists who were blinded to clinical information. Interreader agreement was assessed, and multivariable logistic regression was also used. Results A total of 62 patients (mean age Â± standard deviation, 42.1 years Â± 11.9; 38 women) were included. SSI was diagnosed in 20 of the 62 patients (32%) (mean age, 43 years Â± 12); 42 patients (68%) did not have SSI (mean age, 41 years Â± 10). Reader 1 detected distal cam in 16 of the 20 patients with SSI (80%) and eight of the 42 patients without SSI (19%), and reader 2 detected distal cam in 15 of the 20 patients with SSI (75%) and eight of the 42 patients without SSI (19%) (P < .001 for both). Reader 1 detected signs of impingement on the distal femoral neck (IDFN) in 18 of the 20 patients with SSI (90%) and seven of the 42 patients without SSI (16%), and reader 2 detected signs of IDFN in 13 of the 20 patients with SSI (65%) and nine of the 42 patients without SSI (21%) (P < .001 and P = .001, respectively). Reader 1 detected superior capsular edema in 15 of 20 patients with SSI (75%) and three of 42 patients without SSI (7%), and reader 2 detected superior capsular edema in 17 of 20 patients with SSI (85%) and 22 of 42 patients without SSI (52%) (P < .001 and P = .02, respectively). Distal cam was a predictor of SSI after adjustment for IDFN. Interreader agreement was substantial for distal cam (Îº = 0.80) and moderate for IDFN (Îº = 0.50). Conclusion Soft-tissue injuries and osseous findings other than morphologic features of the anterior inferior iliac spine were associated with subspine impingement. Â© RSNA, 2019 See also the editorial by Guermazi in this issue.
An Evaluation of Guideline-Discordant Ordering Behavior for CT Pulmonary Angiography in the Emergency Department
PURPOSE/OBJECTIVE:The aim of this study was to determine rates of and possible reasons for guideline-discordant ordering of CT pulmonary angiography for the evaluation of suspected pulmonary embolism (PE) in the emergency department. METHODS:A retrospective review was performed of 212 consecutive encounters (January 6, 2016, to February 25, 2016) with 208 unique patients in the emergency department that resulted in CT pulmonary angiography orders. For each encounter, the revised Geneva score and two versions of the Wells criteria were calculated. Each encounter was then classified using a two-tiered risk stratification method (PE unlikely versus PE likely). Finally, the rate of and possible explanations for guideline-discordant ordering were assessed via in-depth chart review. RESULTS:The frequency of guideline-discordant studies ranged from 53 (25%) to 79 (37%), depending on the scoring system used; 46Â (22%) of which were guideline discordant under all three scoring systems. Of these, 18 (39%) had at least one patient-specific factor associated with increased risk for PE but not included in the risk stratification scores (eg, travel, thrombophilia). CONCLUSIONS:Many of the guideline-discordant orders were placed for patients who presented with evidence-based risk factors for PE that are not included in the risk stratification scores. Therefore, guideline-discordant ordering may indicate that in the presence of these factors, the assessment of risk made by current scoring systems may not align with clinical suspicion.
Real-Time Assessment of Femoroacetabular Motion Using Radial Gradient Echo Magnetic Resonance Arthrography at 3Â Tesla in Routine Clinical Practice: A Pilot Study
PURPOSE/OBJECTIVE:To compare femoroacetabular motion in a series of consecutive symptomatic patients with hip pain throughout the range of motion of the hip using a real-time radial gradient echo (GRE) sequence in addition to the routine hip protocol sequences for magnetic resonance (MR) arthrographic assessment of patients with and without clinical femoroacetabular impingement (FAI) syndrome. In particular, we sought to assess whether the additional dynamic sequence could differentiate between patients with and without a positive physical exam maneuver for FAI syndrome. METHODS:Patients with hip pain referred for conventional hip MR arthrogram including those with and without a positive physical exam maneuver for FAI syndrome were imaged using routine hip MR arthrogram protocol and an additional real-time radial 2-dimensional GRE acquisition at 3Â Tesla in an axial oblique plane with continuous scanning of a 9Â mm thick slice through the center of the femoral head-neck axis. Patients who were unable to move through the range of motion were excluded (nÂ = 3). Patients with acetabular dysplasia (defined by a lateral center-edge angle [CEA] of 20Â°) were also excluded, as were patients had Kellgren and Lawrence scores of > 0. The real-time cine sequence was acquired with the patient actively moving through neutral, flexion, flexion-abduction external-rotation, and flexion-adduction internal rotation (FADIR) positions aiming for 40Â° of abduction, then 25Â° of adduction at 80Â° to 90Â° flexion. Due to the placement of the coil over the hip, a true FADIR was precluded. Images were evaluated independently by 2 musculoskeletal radiologists measuring the joint space in the anterior, central, and posterior positions at each point during range of motion for femoroacetabular cortical space (FACS). Anterior FACS narrowing was calculated as the ratio of joint space in FADIR:neutral position, with lower ratios indicating greater narrowing. Static metrics including alpha angle, CEA, grade of cartilage loss according the Outerbridge classification, and patient demographics were also recorded. RESULTS:Twenty-two painful hips in 22 patients (11 males and 11 females) with mean age 36Â years (range, 15-67) were included. Twelve patients had a positive physical exam maneuver for FAI syndrome. The time to perform the dynamic sequence was 3 to 6Â minutes. Interobserver agreement was strong, with intraclass correlation 0.91 and concordance correlation 0.90. According to results from both readers, patients with impingement on clinical exam had significantly lower anterior FACS ratios compared with those without clinical impingement (reader 1: 0.39 Â± 0.10 vs 0.69 Â± 0.20, PÂ = .001; reader 2: 0.36 Â± 0.07 vs 0.70 Â± 0.17, P < .001). Decreased anterior FACS ratio was found to be significantly correlated to increased alpha angle by both readers (reader 1: RÂ =Â -0.63, PÂ = .002; reader 2: RÂ =Â -0.67, PÂ = .001) but not significantly correlated to CEA (reader 1: RÂ = 0.13, PÂ = .561; reader 2: RÂ = 0.20, PÂ = .378) or cartilage loss (reader 1: RÂ = 0.03, PÂ = .885; reader 2: RÂ =Â -0.06, PÂ = .784). Both readers found patients with an anterior FACS ratio of 1/2 to have significantly higher mean alpha angle (reader 1: 62.88 vs 52.79, PÂ = .038; reader 2: 63.50 vs 50.58, PÂ = .006); however, there were no significant differences in cartilage loss (reader 1: PÂ = .133; reader 2: PÂ = .882) or CEA (reader 1: PÂ = .340; reader 2: PÂ = .307). CONCLUSIONS:A dynamic radial 2-dimensional-GRE sequence can be added to standard hip MR arthrogram protocols in <6Â minutes, allowing assessment of dynamic femoroacetabular motion with strong interreader agreement. Patients with impingement on clinical exam had significantly lower anterior FACS ratios between FADIR and neutral positions, compared with those without clinical impingement. LEVEL OF EVIDENCE/METHODS:Level III, comparative diagnostic investigation.
Artificial Intelligence in Musculoskeletal Imaging: Current Status and Future Directions
OBJECTIVE. The objective of this article is to show how artificial intelligence (AI) has impacted different components of the imaging value chain thus far as well as to describe its potential future uses. CONCLUSION. The use of AI has the potential to greatly enhance every component of the imaging value chain. From assessing the appropriateness of imaging orders to helping predict patients at risk for fracture, AI can increase the value that musculoskeletal imagers provide to their patients and to referring clinicians by improving image quality, patient centricity, imaging efficiency, and diagnostic accuracy.
Downstream Costs Associated with Incidental Pulmonary Nodules Detected on CT
RATIONALE AND OBJECTIVES/OBJECTIVE:To explore downstream costs associated with incidental pulmonary nodules detected on CT. MATERIALS AND METHODS/METHODS:The cohort comprised 200 patients with an incidental pulmonary nodule on chest CT. Downstream events (chest CT, PET/CT, office visits, percutaneous biopsy, and wedge resection) were identified from the electronic medical record. The 2017 Fleischner Society Guidelines were used to classify radiologists' recommendations and ordering physician management for the nodules. Downstream costs for nodule management were estimated from national Medicare rates, and average costs were determined. RESULTS:Average downstream cost per nodule was $393. Costs were greater when ordering physicians over-managed relative to radiologist recommendations ($940) vs. when adherent ($637) or under-managing ($166) relative to radiologists recommendations. Costs were also greater when ordering physicians over-managed relative to Fleischner Society guidelines ($860) vs. when under-managing ($208) or adherent ($292) to guidelines. Costs did not vary significantly based on whether or not radiologists recommended follow-up imaging ($167-$397), nor whether radiologists were adherent or under- or over-recommended relative to Fleischner Society guidelines ($313-$444). Costs were also higher in older patients, patients with a smoking history, and larger nodules. Five nodules underwent wedge resection and diagnosed as malignancies. No patient demonstrated recurrence or metastasis. Average cost per diagnosed malignancy was $3090. CONCLUSION/CONCLUSIONS:Downstream costs for incidental pulmonary nodules are highly variable and particularly high when ordering physicians over-manage relative to radiologist recommendations and Fleischner Society guidelines. To reduce unnecessary utilization and cost from over-management, radiologists may need to assume a greater role in partnering with ordering physicians to ensure appropriate, guideline-adherent, and follow-up testing.
Multilevel glenoid morphology and retroversion assessment in Walch B2 and B3 types
OBJECTIVE:A major factor that impacts the long-term outcome and complication rates of total shoulder arthroplasty is the preoperative posterior glenoid bone loss quantified by glenoid retroversion. The purpose of this study was to assess if glenoid retroversion varies significantly at different glenoid heights in Walch B2 and B3 glenoids. MATERIALS AND METHODS/METHODS:Patients with B2 and B3 glenoid types were included following retrospective review of 386 consecutive CT shoulder studies performed for arthroplasty preoperative planning. True axial CT reconstructions were created using a validated technique. Two readers independently measured the glenoid retroversion angles according to the Friedman method using the "intermediate" glenoid at three glenoid heights: 75% (upper), 50% (equator), and 25% (lower). The variances between the three levels for a given patient were calculated. RESULTS:Twenty-nine B2 and 8 B3 glenoid types were included. There was no significant difference in variance of glenoid version among the three levels in B2 or B3 groups. The mean variance in retroversion degree between equator-lower, upper-equator, and upper-lower glenoid was -Â 0.4, 0.3, andâ€‰-â€‰0.2 for B2; andâ€‰-â€‰0.2, 1.9, and 1.9 for B3 glenoid, respectively. The level of inter-reader agreement was fair to good for variance at equator-lower, and good to excellent for upper-equator and upper-lower glenoid. CONCLUSIONS:Glenoid version can be accurately measured at any level between 25 and 75% of glenoid height for Walch B2 and B3. We recommend that the glenoid equator be used as the reference to assure consistent and reliable version measurements in this group of patients.