Faculty Bibliography

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

OBJECTIVE: To describe the post-surgical imaging appearance and complications of high tibial osteotomy in patients with the iBalance implant system (iHTO; Arthrex, Naples, FL, USA). MATERIALS AND METHODS: Retrospective, institutional review board-approved, Health Insurance Portability and Accountability Act-compliant review of imaging after 24 iBalance procedures was performed with attention to: correction of varus malalignment, healing at the osteotomy site, resorption of the osteoinductive compound, and complications. RESULTS: Immediate correction of the varus deformity was present in all cases. Lobular radiolucency was present in all cases, more pronounced on the lateral knee radiograph, simulating infection or erosive disease. Four radiographic signs of healing were observed: blurring at the opposing osteotomy bony margins and at the osteoinductive compound and the adjacent bone interface, callus formation, and resorption of the osteoinductive compound. Complications were present in 33 % of cases, including fracture through the lateral tibial cortex (21 %), genu varum recurrence (8 %), painful exuberant bone formation (4 %), persistent pain, requiring total knee arthroplasty (4 %), and non-union (after >6 months' follow-up), with suspected infection (4 %). CONCLUSION: Radiologists should be aware of the normal radiographic appearance following iBalance high tibial osteotomy, which may be confused with infection. Radiologists should also be aware of potential post-operative complications and compare all post-operative radiographs with the immediate post-operative examination to detect collapse of the osteotomy site and recurrence of varus angulation.

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.

Purpose: Examine the accuracy of diagnosing adhesive capsulitis (AC) on MRI, using physical exam and clinical impression of an orthopedic sports clinician as the diagnostic reference standard. Materials and Methods: Retrospective query of our digital database was performed to identify all shoulder MRIs performed at our institution in 2013. The first 100 consecutive subjects aged >40 were included for further review. MRI reports were assessed for the presence of the following information: 1. Thickening of the capsule at the axillary recess (AR), 2. Thickening of the coracohumeral ligament (CHL), 3. Infiltration/ edema of subcoracoid fat, 4. Disproportionate fluid within the proximal biceps tendon sheath, and 5. Imaging impression ofAC. Orthopedic notes were assessed for documented range of shoulder motion and overall clinical impression (10 sports fellowship-trained orthopedic surgeons, 1 shoulder and elbow fellowship-trained orthopedic surgeon, and 1 sports medicine trained primary care physician). Sensitivity, specificity, negative predictive value (NPV), positive predictive value (PPV) and overall accuracy were calculated. Fisher exact tests were performed to determine whether each imaging finding was predictive of a positive clinical diagnosis of AC, or likely to predispose to a false positive diagnosis of AC. Results: One hundred shoulder MRI reports in 99 patients were analyzed (59men, 40 women;mean age 58, range 40-87). 17 patients were diagnosed with AC based on imaging findings. Of these patients, frequency of imaging findings included: thickening of the AR (11) or the CHL (8), infiltration of subcoracoid fat (13), and disproportionate fluid in the proximal biceps tendon sheath (3). Six patients had a clinical diagnosis of AC. Fifteen MRIs demonstrated false positive results, while false negative results were seen in 4 cases. The overall sensitivity for theMRI diagnosis of AC was 33.3%with a specificity of 84%. The PPV was 11.8 %,NPV 95.2 %, and overall accuracy 81 %. Fisher exact test P values to determine whether each imaging finding was predictive of a reference standard diagnosis of AC ranged from 0.109 to 1.000. P values to determine whether each imaging finding would lead to a false positive MRI diagnosis were <0.001 for subcoracoid fat infiltration, thickening of the AR, and thickening of the CHL, and p = 1.000 for disproportionate fluid in the biceps tendon sheath. Conclusion: The predictive value of the established MRI findings of adhesive capsulitis may not be as strong as previously shown. Radiologists should be aware of potential imaging over diagnosis and should correlate imaging findings with documented physical exam, when available

Purpose: The bare area (BA) is a central, well-circumscribed focal defect in the articular surface of the glenoid, with reported adult incidence of 1- 2 %. The adult literature supports a developmental etiology, however, a recent imaging study, based on a pediatric patient population, suggested a similar incidence of BA but advocated a traumatic origin. The purpose of our study was to reassess the prevalence and MRI appearance of the glenoid bare area in the pediatric population. Materials and Methods: Retrospective review of our digital database from 6/2014 to 10/2015 identified 150 shoulderMRI in children between 10 and 18 years of age. The patients were divided into 2 age groups: group 1, 10-15 years (n = 75) and group 2, 15-18 years (n=75). The bare area was defined as a well marginated, central defect, of increased signal in the articular surface of the glenoid, seen on at least 2 imaging planes, without evidence of underlying glenoid pathology. The presence, location and size of the BAwere documented in each group. Results: A total of 19 BA were identified, 15 (20 %) in group 1 and 4 (5 %) in group 2, with a significantly higher incidence in the younger group (p = 0.007, Chi Square Test). Location was mainly central (12 (80 %) in group 1, 3 (75 %) in group 2). The mean size was 3.44 mm, range, 1.5-7.5 mm in group 1; mean size of 2.47 mm, range, 1.6-3.2 mm in group 2. Conclusion: The incidence of the BA in children ranging from 10 to 15 years of age is significantly higher than in older children and higher than the reported incidence in adults. The BA is also larger in the younger compared to the older pediatric age group. Our findings may be explained by the centripetal pattern of ossification of the glenoid and, thus, give support to the normal developmental theory. Familiarity with the MR appearance of the BA should obviate misinterpreting as a pathologic condition in the pediatric patient population

Purpose: Assess, utilizing MRI, the normal maturation and stress injury to the coracoid process and bipolar growth plate, at the interface with the underlying scapula. To the best of our knowledge this has not yet been described in the literature. Materials and Methods: The study was divided into 2 parts: (A) Maturation of the coracoid process and bipolar growth plate. Retrospective review of 182 consecutive shoulder MRIs in 160 children without clinical or MRI evidence of coracoid pathology (107 boys, 53 girls, ages 0 to <5, n=36, 5 to <10, n = 25, 10 to <15, n = 67, and 15 to 18, n = 54). The studies were reviewed with special attention to the development and fusion of the coracoid to the scapula, via the bipolar growth plate. (B) Growth plate injuries. Retrospective review of shoulder MRIs with coracoid growth plate disturbance (7 boys, 1 girl, mean age 15). Results: (A)Maturation of the coracoid process and bipolar growth plate. At 0 to <5 years the cartilaginous coracoid precursor conformed to the shape of a mature coracoid process, with a small oval primary ossification center within it. The bony margins at the coracoid-scapular interface transformed from smooth to irregular with advancing age. At 5 to <10 years of age, a more distinct, undulating, bipolar growth plate developed. Complete closure of the bipolar plate was observed as early as 11 years of age and was noted in 41 % of patients by age 14 and in 86 % of 15 to 18 year olds. (B) Growth plate injuries. The 8 patients with growth plate stress injuries included 2 patients with neuromuscular disorders and 6 patients with sports related symptoms. The growth plate demonstrated widening, irregularity, and increased signal, with surrounding soft tissue and opposing bony marrow edema and hypertrophy. Conclusion: MRimaging of normal maturation as well as stress injury of the base of the coracoid is crucial for accurate imaging diagnosis. Injury to the base of the coracoid, while uncommon, should be considered when assessing adolescents with shoulder symptomatology

BACKGROUND: Ultrasound elastography allows assessment of tissue elasticity. To the best of our knowledge, the elastography appearance of muscles in normal children has not been described. OBJECTIVE: To determine the US elasticity of muscles in children at rest and following exercise. MATERIALS AND METHODS: Cine elastography of biceps brachii and rectus femoris muscles was obtained at rest and after exercise in 42 healthy children (23 males, 19 females; mean: 11.2 +/- 4.4 years, range: 2-18 years). Elastography scores were assigned to each clip based on a five-point color scale. Mean elastography scores and standard deviations were calculated and resting and postexercise elastography scores were compared. RESULTS: Resting muscle elasticity was lower in the biceps brachii than in the rectus femoris (P = 0.008), and higher in the dominant than in the nondominant biceps brachii (P < 0.032). Rectus femoris elasticity was higher in males than females (P = 0.051). Postexercise muscle elasticity significantly increased in both the dominant and nondominant biceps brachii (P < 0.001) and in the rectus femoris (P < 0.001). There was no significant gender-related difference in postexercise muscle elasticity. Biceps brachii elasticity decreased and rectus femoris elasticity increased with increasing body mass index. Younger subjects had a greater change in muscle elasticity with exercise. CONCLUSION: Resting muscle elasticity in children is significantly lower in the biceps brachii than in the rectus femoris and in the nondominant biceps brachii than in the dominant biceps brachii. Elasticity significantly increases immediately postexercise in both muscle groups; resting differences between biceps brachii and rectus femoris elasticity, and dominant and nondominant biceps brachii elasticity, do not persist after exercise. The change in muscle elasticity with exercise is higher in younger children.

OBJECTIVE: The purpose of this article is to compare 3D T2-weighted sampling perfection with application-optimized contrast with different flip-angle evolutions (SPACE) with three-plane 2D turbo-spin echo (TSE) sequences for female pelvic imaging at 3 T. MATERIALS AND METHODS: Twenty women were imaged with 2D TSE and 3D SPACE sequences. Three radiologists independently assessed image quality, diagnostic quality, and artifacts; measured normal anatomic structures; evaluated pathologic abnormalities; and recorded interpretation time. Readers subsequently performed a side-by-side comparison, and their preferences were graded according to overall interpretation, sharpness of lesion edges, motion and other artifacts, uterine and cervical zonal anatomy distinction, identification of adnexal pathologic abnormalities, and distinction between fat and fluid. Quantitative comparison of relative signal intensity and relative tissue contrast was performed. RESULTS: The mean acquisition time of 3D SPACE was significantly shorter than that of 2D TSE (6 minutes 35 seconds vs 8 minutes 50 seconds; p < 0.005). Intrareader agreement between interpretations of 2D and 3D sequences was excellent. There were no significant differences among readers in detecting artifacts, normal structures, and pathologic abnormalities or in determining endometrial thickness, image quality, or interpretation time (p > 0.05). Except for distinctions between fat and fluid, the average reader score indicated a slight preference for the 3D sequence. Three-dimensional multiplanar reconstructions were helpful but not considered essential. Relative agreement between readers was moderate (r >/= 0.4) to strong (r >/= 0.7). The relative signal intensity was higher for fat and bladder fluid on the 3D sequence than on the 2D sequence (p = 0.014 and p = 0.018, respectively). Relative tissue contrast was higher for the 3D sequence (p < 0.05), with no significant difference in bladder or fat contrast (p = 0.31) but a trend toward more superior contrast on the 2D sequence. CONCLUSION: At 3 T, 3D SPACE has similar image quality and diagnostic quality with shorter scan time when compared with 2D TSE but with reduced contrast between fat and fluid

The pathology, assessment, and management of articular cartilage lesions of the hip and knee have been the subject of considerable attention in the recent orthopaedic literature. MRI has long been an important tool in the diagnosis and management of articular cartilage pathology, but detecting and interpreting early cartilaginous degeneration with this technology has been difficult. Biochemical-based MRI has been advocated to detect early cartilaginous degenerative changes and assess cartilage repair. Techniques such as T2 mapping, T1rho (ie, T1 in the rotating frame), sodium MRI, and delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) take advantage of changes in the complex biochemical composition of articular cartilage and may help detect morphologic cartilaginous changes earlier than does conventional MRI. Although the newer modalities have been used primarily in the research setting, their ability to assess the microstructure of articular cartilage may eventually enhance the diagnosis and management of osteoarthritis

Renal replacement lipomatosis is a rare benign entity in which extensive fibrofatty proliferation of the renal sinus is associated with marked renal atrophy. In this report, we present a case of massive renal replacement lipomatosis demonstrated on MRI. The presentation was atypical given an absence of associated renal calculus disease, and an initial CT scan was interpreted as suspicious for a liposarcoma. The differential diagnosis and key MRI findings that served to establish this specific diagnosis are reviewed. Histopathological correlation is also presented, as the patient underwent nephroureterectomy