Faculty Bibliography

Purpose: Study the diagnostic accuracy of the 'smoke sign' on routine shoulder MR examinations for detection of pectoralis tendon humeral insertional injury.
Material(s) and Method(s): IRB approved, HIPAA compliant study. Radiology database queried for MR with reports containing 'pectoralis' and 'shoulder' from 9/2012 to 7/2018. Patients without prior pectoralis surgery with shoulder and pectoralis MR within 4 months, and shoulder MRpositive for pectoralis injury based on report and imaging review that clearly depicted pectoralis injury were included. Anonymized, randomized shoulder MR reviewed independently by two musculoskeletal fellowship-trained radiologists for 'smoke sign' on coronal- and sagittal-oblique sequences. Teaching session provided guidelines for smoke sign (ill-defined edema lateral or anterior to short head biceps/ coracobrachialis on coronal- and sagittal-oblique fluid-sensitive images, respectively) before reader review. AllMR reviewed by senior author for presence and location of pectoralis injury.
Result(s): 52 shoulder MR exams total: 33 patients with shoulder and pectoralis MR, 4 patients with shoulder MR and pectoralis imaging on same exam, 15 patients with shoulder MR only.14/52 exams didn't have pectoralis injury on shoulder or pectoralis MR; 'smoke sign' was present in none of these cases. Remaining 38 patients had pectoralis injuries; 24/38 (humeral avulsion), 4/38 (tendon tear) 8/38 (myotendinous junction), 2/38 (intramuscular injury). Pooled sensitivity, specificity, negative and positive predictive value for 'smoke sign' was 86%, 100%, 76% and 100%. When only tendon tears and avulsions were assessed, this rose to 100%, 100%, 100% and 100%. Kappa coefficient was 0.922 for the presence of the sign on coronal oblique 0.876 on sagittal oblique images. Smoke sign was present in all 8 surgically proven pectoralis injuries.
Conclusion(s): 'Smoke sign' is sensitive and specific for pectoralis humeral insertional injury, especially tendon tears and avulsions. Detection of this sign on routine shoulder MR should prompt careful evaluation of the distal pectoralis tendon and recommendation for dedicated pectoralis imaging

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.

Purpose: Talocalcaneal coalition and medial ankle accessory muscles can both predispose to tarsal tunnel syndrome due to stretching and extrinsic compression of the posterior tibial nerve and its branches in the tarsal tunnel. We have anecdotally observed a high proportion of medial accessory ankle muscles in patients with talocalcaneal coalitions. The purpose of our study was to assess this previously unrecognized association with the hypothesis that this may be an additional cause for tarsal tunnel syndrome in patients with talocalcaneal coalition. Materials and Methods: A search of our department imaging database, utilizing the keyword "coalition" yielded 79 cases. Images were retrospectively reviewed by two musculoskeletal (MSK) radiologists for the presence of medial ankle accessory muscles, including: accessory soleus, accessory flexor digitorum longus, and peroneocalcaneus internus. In addition, 30 cases, selected from the final cohort, were reviewed independently by two (MSK) readers to determine interobserver agreement utilizing the kappa coefficient. Results: The final cohort included 67 ankle MRIs in 65 patients, part of a cohort previously published describing the association of talocalcaneal coalitions and soft tissue pathology in the tarsal tunnel, (35 men, 30 women, age range 8-72 years, mean age, 40 years). Overall n = 14 (21%) of patients with talocalcaneal coalition had a medial sided accessory muscle, including accessory flexor digitorum longus muscle in 8 ankles (12% compared to 2-8% reported in the general population), a peroneocalcaneus internus in 4 ankles (6% compared to 1% reported in the general population) and an accessory soleus in 2 ankles (3% compared to 0.7-5.5% of the general population). The kappa coefficient was calculated as 0.61, demonstrating substantial agreement among readers in detecting medial accessory muscles. Conclusion: Medial sided accessory ankle muscles are more common in patients with talocalcaneal coalitions compared to the general population, with the most common muscle being the accessory flexor digitorum longus. It is important for radiologists to be aware of medial accessory muscles as an additional cause for tarsal tunnel syndrome in patients with talocalcaneal coalition, a cohort already predisposed to compression of soft tissue structures by coalition related bony excrescences and hindfoot valgus deformity

OBJECTIVE: To assess, utilizing MRI, tarsal tunnel disease in patients with talocalcaneal coalitions. To the best of our knowledge, this has only anecdotally been described before. MATERIALS AND METHODS: Sixty-seven ankle MRIs with talocalcaneal coalition were retrospectively reviewed for disease of tendons and nerves of the tarsal tunnel. Interobserver variability in diagnosing tendon disease was performed in 30 of the 67 cases. Tarsal tunnel nerves were also evaluated in a control group of 20 consecutive ankle MRIs. RESULTS: Entrapment of the flexor hallucis longus tendon (FHL) by osseous excrescences was seen in 14 of 67 cases (21 %). Attenuation, split tearing, tenosynovitis, or tendinosis of the FHL was present in 26 cases (39 %). Attenuation or tenosynovitis was seen in the flexor digitorum longus tendon (FDL) in 18 cases (27 %). Tenosynovitis or split tearing of the posterior tibial tendon (PT) was present in nine cases (13 %). Interobserver variability ranged from 100 % to slight depending on the tendon and type of disease. Intense increased signal and caliber of the medial plantar nerve (MPN), indicative of neuritis, was seen in 6 of the 67 cases (9 %). Mildly increased T2 signal of the MPN was seen in 15 (22 %) and in 14 (70 %) of the control group. CONCLUSIONS: Talocalcaneal coalitions may be associated with tarsal tunnel soft tissue abnormalities affecting, in decreasing order, the FHL, FDL, and PT tendons, as well as the MPN. This information should be provided to the referring physician in order to guide treatment and improve post-surgical outcome.

OBJECTIVE: Assess extensor carpi ulnaris (ECU) tendon position in the ulnar groove, determine the frequency of tendon "dislocation" with the forearm prone, neutral, and supine, and determine if an association exists between ulnar groove morphology and tendon position in asymptomatic volunteers. MATERIALS AND METHODS: Axial proton density-weighted MR was performed through the distal radioulnar joint with the forearm prone, neutral, and supine in 38 asymptomatic wrists. The percentage of the tendon located beyond the ulnar-most border of the ulnar groove was recorded. Ulnar groove depth and length was measured and ECU tendon signal was assessed. RESULTS: 15.8 % of tendons remained within the groove in all forearm positions. In 76.3 %, the tendon translated medially from prone to supine. The tendon "dislocated" in 0, 10.5, and 39.5 % with the forearm prone, neutral and supine, respectively. In 7.9 % prone, 5.3 % neutral, and 10.5 % supine exams, the tendon was 51-99 % beyond the ulnar border of the ulnar groove. Mean ulnar groove depth and length were 1.6 and 7.7 mm, respectively, with an overall trend towards greater degrees of tendon translation in shorter, shallower ulnar grooves. CONCLUSIONS: The ECU tendon shifts in a medial direction when the forearm is supine; however, tendon "dislocation" has not been previously documented in asymptomatic volunteers. The ECU tendon medially translated or frankly dislocated from the ulnar groove in the majority of our asymptomatic volunteers, particularly when the forearm is supine. Overall greater degrees of tendon translation were observed in shorter and shallower ulnar grooves.

Purpose: Medial hindfoot coalitions, particularly posterior extra-articular and overlap coalitions, may have large medial and posteromedial osseous excrescences which extend into and produce, in conjunction with flat foot deformity, stretching and mass effect on the tarsal tunnel. Resection of the coalition without addressing pathology of these soft tissue structures can result in surgical failure and continued disability to the patient. Yet, to the best of our knowledge, there is scant information about this topic in the literature. We hypothesize that soft tissue disease in the tarsal tunnel is a frequent phenomenon, in the setting of hindfoot coalitions. Materials and Methods: A search of our ankle MRI data base revealed 88 cases with medial hindfoot coalitions. All cases were independently and retrospectively reviewed by 2 musculoskeletal radiologists for the presence of neuritis, manifested by focally increased nerve caliber and signal, of the posterior tibial nerve and its medial and lateral plantar branches. The posterior tibial (PT), flexor hallucis longus (FHL) and flexor digitorum longus (FDL) were assessed for the presence of tendinosis, tenosynovitis and partial tearing. Results: The final cohort included 68 cases of medial hindfoot (middle, posterior extra-articular and overlap) coalition (37 men, 31 women, average age 40, range 72-8). Neuritis of the posterior tibial nerve and its branches (n = 18, 26 %) was more commonly noted in the medial plantar nerve. Entrapment of FHL by osseous coalition-related posteromedial excrescences was seen in 14 cases (21 %). Other tendon disorders such as flattening and stretching against sharp bony edges, tendinosis, partial tearing and tenosynovitis were noted in the FHL (n = 30, 44 %) and FDL (n = 22, 32 %). PT tendinosis and tearing was less common (n=9, 13%). Conclusion: Medial hindfoot coalitions are commonly associated with tarsal tunnel soft tissue abnormalities affecting the posterior tibial nerve and its branches, the FHL tendon and less commonly FDL and PT tendons. The radiologist should alert the referring physician for the presence of tarsal tunnel abnormalities in the presence of medial hindfoot coalition since these can guide surgical treatment and outcome

Purpose: To compare the accuracy of an optimized 3D TSE (SPACE) sequence using SPARSE-SENSE (SS) acceleration with 2D TSE sequences for the detection of internal derangement of the knee. Materials and Methods: An optimized accelerated SPACE sequence prototype was developed using avariable-density poisson-disc undersampling pattern of the two phase-encoding dimensions. Optimized parameters were: TR1100, TE22, TF28, variable flip angle evolution for PD weighting, SS undersampling factor of 9, fat suppression, presence of an optimized MT module, and 0.5 x 0.5 x 0.6 mm3 voxel size. This sequence (TA 4:57) was added to our conventional knee examination (sagittal PD and FS T2, coronal PD and FS PD, axial FS T2 2D TSE sequences (TA 10:56)) for 579 patients undergoing knee MR examinations imaged on a 3T scanner (Magnetom Skyra, Siemens Healthcare). An iterative SS reconstruction [2] was performed by enforcing sparsity in the wavelet representation of the knee images. Images were then reformatted in all 3 orthogonal planes at 1.5mmthickness. 50 of the 579 patients underwent arthroscopy of the knee and two experienced MSK radiologists blindly reviewed the SS SPACE sequence and the conventional 2D TSE sequences of these 50 patients at separate sittings to evaluate for the presence of meniscal or ligamentous tears. Results: 38 patients hadmedialmeniscal tears, 23 had lateral meniscal tears, and 16 had ACL tears. There was only 1 MCLand PCL tear and there were no LCL tears. The sensitivity, specificity, and accuracy for medial meniscal, lateral meniscal, and ACL tears on the 2D TSE images and SS Space images for each reader are presented below. Sensitivity Specificity Accuracy Sensitivity Specificity Accuracy Conclusion: An optimized and accelerated 3D TSE sequence has the potential to replace 2D TSE sequences for evaluation of internal derangement of the knee. If substantiated in larger clinical studies, this could lead to significant shortening of exam time, potentially enlarging the indication and utilization of knee MR as well as decreasing its cost

OBJECTIVE: Assess the diagnostic accuracy of 3-T indirect magnetic resonance arthrography (iMRA) for hip cartilage and labral pathology detection using arthroscopy as the reference standard and compare it to the published performance of direct magnetic resonance arthrography (dMRA). MATERIALS AND METHODS: Between 2009 and 2011, 290 patients suspected of having femoroacetabular impingement underwent iMRA. Our study group consisted of 41 of these patients (17 males, mean age 35 years; 24 females, mean age 33 years) who did not have a prior history of hip surgery and who subsequently underwent arthroscopy. Two experienced musculoskeletal radiologists separately evaluated the randomized and anonymized studies for the presence and quadrant location of labral and cartilage pathology. These recorded data were compared to arthroscopic reports. RESULTS: Forty-one patients had labral pathology, 34 patients had acetabular and 5 patients had femoral cartilage pathology at arthroscopy. Sensitivity, specificity, accuracy, negative- and positive-predictive values for labral lesion detection were respectively 98, 99, 99, 99 and 98 %; for acetabular cartilage lesion detection they were 69, 98, 89, 87 and 95 %; for femoral cartilage lesion detection they were 69, 95, 93 and 39 %. Sensitivities of iMRA by quadrant (anteroinferior, anterosuperior, posteroinferior, posterosuperior) for the labrum were 100.0, 95.0, NA and 85.7 %, for acetabular cartilage were NA, 58.8, NA and 39.5 % and for femoral cartilage were 50.0, 33.3, 75.0 and 75.0 %). NA indicates results not available because of the absence of findings in those quadrants. Specificities of iMRA by quadrant (anteroinferior, anterosuperior, posteroinferior, posterosuperior) for the labrum (95.0, 100.0, 95.1, 67.5 %), acetabular (100.0, 85.7, 92.6, 79.5 %) and femoral cartilage (100.0, 94.7, 96.2, 85.9 %). CONCLUSION: iMRA at 3 T is accurate in detecting labral pathology suggesting that it is a viable alternative to dMRA.

Three cases of PIN palsy following biceps repair are presented with clinical and imaging correlation. The imaging findings in these cases will be discussed and the orthopedic literature, as regards possible surgical approaches and technical factors believed to predispose to or prevent this complication, will be reviewed. It is important for radiologists to serve as consultants in these uncommon but sometimes devastating complications, helping to quickly and accurately recognize the imaging findings corresponding to the clinical symptoms and aiding the surgeon in diagnosis and treatment by identifying the possible causes and sites of nerve compression.