Faculty Bibliography

OBJECTIVE:We previously reported improved body composition and cardiovascular risk markers plus a small decrease in glucose tolerance with GH administration vs placebo for 6 months to abdominally obese premenopausal women. The objective of this study was to determine whether the effects of GH treatment on cardiovascular risk markers, body composition and glucose tolerance in obese women persist 6 months after GH withdrawal. DESIGN AND PATIENTS/METHODS:Fifty abdominally obese premenopausal women completed a trial of rhGH vs placebo for 6 months; thirty-nine women completed a subsequent 6-month withdrawal observation period. MEASUREMENTS/METHODS:IGF-I, body composition by CT, (1) H-MRS and DXA, serum cardiovascular risk markers, oral glucose tolerance test (OGTT). RESULTS:IGF-I standard deviation scores (SDS) within the GH group were -1.7 ± 0.1 (pretreatment),-0.1 ± 0.3 (after 6 months of GH) and -1.7 ± 0.1 (6 months post-GH withdrawal). Six months after GH withdrawal, total abdominal and subcutaneous adipose tissue, total fat, trunk fat, trunk/extremity fat, hsCRP, apoB, LDL, and tPA were higher than at the 6-month (GH discontinuation) timepoint (P ≤ 0.05). All body composition and cardiovascular risk markers that had improved with GH returned to baseline levels by 6 months after GH discontinuation, as did fasting and 2-h OGTT glucose levels. CONCLUSION/CONCLUSIONS:The effects of GH administration to abdominally obese premenopausal women have a short time-course. The beneficial effects on body composition and cardiovascular risk markers, and the side effect of altered glucose tolerance returned to pretreatment levels after GH withdrawal. There was no suppression of endogenous IGF-I levels, which returned to baseline after GH withdrawal.

OBJECTIVE:To examine the association between inframalleolar peroneal tendon abnormalities and an enlarged peroneal tubercle. MATERIALS AND METHODS/METHODS:Two independent readers evaluated consecutive ankle MR imaging studies to classify inframalleolar peroneal tendon findings as normal, tenosynovitis, partial tear or complete tear. The size and morphology of the peroneal tubercle was also recorded. We performed statistical analyses for inter-observer agreement and to assess differences in peroneal tubercle size between groups with and without peroneal tendon abnormalities. RESULTS:The study group comprised 121 subjects (mean age, 45.5 years) of whom 28% (34 out of 121) had lateral ankle symptoms. The peroneal tubercle was absent in 56% of subjects (68 out of 121). In subjects with a peroneal tubercle (>0 mm), the mean size was 3.5 mm (37% triangular and 7% plateau-shaped). Male subjects had significantly larger mean peroneal tubercle size than female subjects (2.1 ± 2.5 vs 1.2 ± 1.9 mm, P = 0.04). Overall, 26% (32 out of 121) of subjects had some peroneal tendon abnormality: 17% (20 out of 121) had tenosynovitis and 17 % (20 out of 121) had partial thickness tears. The peroneal tubercle size was significantly larger in subjects with peroneal tendon partial tears (P = 0.036), tenosynovitis (P < 0.001), and when both abnormalities were present (P = 0.007). ROC statistic showed 73% sensitivity and 74% specificity for detection of partial tears for peroneal tubercle size ≥4.3 mm. CONCLUSION/CONCLUSIONS:Our study shows a significantly larger peroneal tubercle in subjects with inframalleolar peroneal tendon abnormalities. A cut-off of 4.3 mm showed good sensitivity and specificity for the presence of partial tears of the peroneal tendon.

OBJECTIVE:The objective of this study was to determine the prevalence of extrinsic wrist ligament injury by magnetic resonance imaging and its association with intrinsic ligament tears. METHODS:We reviewed conventional magnetic resonance images performed over a 5-year period from adult patients in the setting of wrist trauma. Two musculoskeletal radiologists examined the integrity of wrist ligaments and presence of bone abnormalities. RESULTS:In a cohort of 75 subjects, extrinsic ligament injury was present in 75%, with radiolunotriquetral being most frequently affected (45%). Intrinsic ligament injury was present in 60%. Almost half of subjects had combined intrinsic and extrinsic ligament injury. Bone abnormalities were seen in 69%. The rate of extrinsic injury was higher in subjects with bone injury (P = 0.008). CONCLUSIONS:There is high prevalence of extrinsic ligament injury in the setting of wrist trauma, especially in the presence of bone abnormalities, with combined injury of intrinsic and extrinsic ligaments in about half of cases.

CONTEXT/BACKGROUND:The elbow is a complex joint and commonly injured in athletes. Evaluation of the elbow by magnetic resonance imaging (MRI) is an important adjunct to the physical examination. To facilitate accurate diagnosis, a concise structured approach to evaluation of the elbow by MRI is presented. EVIDENCE ACQUISITION/METHODS:A PubMed search was performed using the terms elbow and MR imaging. No limits were set on the range of years searched. Articles were reviewed for relevance with an emphasis of the MRI appearance of normal anatomy and common pathology of the elbow. RESULTS:The spectrum of common elbow disorders varies from obvious acute fractures to chronic overuse injuries whose imaging manifestations can be subtle. MRI evaluation should include bones; lateral, medial, anterior, and posterior muscle groups; the ulnar and radial collateral ligaments; as well as nerves, synovium, and bursae. Special attention should be paid to the valgus extension overload syndrome and the MRI appearance of associated injuries when evaluating throwing athletes. CONCLUSION/CONCLUSIONS:MRI evaluation of the elbow should follow a structured approach to facilitate thoroughness, accuracy, and speed. Such an approach should cover bone, cartilage, muscle, tendons, ligaments, synovium, bursae, and nerves.

Soft tissue abnormalities about the hip represent a common clinical problem. Although the signs and symptoms of some of these abnormalities are clinically evident, other entities are frequently overlooked. This article provides an overview and discusses the role of major imaging modalities, especially MR imaging, the primary modality for evaluation of many soft-tissue abnormalities. An introduction to fundamental imaging anatomy and functional roles of soft tissue structures about the hip is provided, recognizing their importance in making the correct diagnosis. Intra-articular and extra-articular soft tissue abnormalities reviewed systematically according to their mechanism of injury and anatomic or functional compartments.

OBJECTIVES/OBJECTIVE:Neurofibromatosis 1 (NF1), NF2, and schwannomatosis are characterized by a predisposition to develop multiple neurofibromas and schwannomas. Currently, there is no blood test to estimate tumor burden in patients with these disorders. We explored whether S100β would act as a biomarker of tumor burden in NF since S100β is a classic immunohistochemical marker of astrocytes, oligodendrocytes and Schwann cells and a small study showed S100β concentrations correlate with the volume of vestibular schwannomas. DESIGN AND METHODS/METHODS:We calculated whole-body tumor burden in subjects with NF1, NF2, and schwannomatosis using whole-body MRI (WBMRI) and measured the concentration of S100β in plasma using ELISA. We used chi-square tests and Spearman rank correlations to test the relationship between S100β levels and whole-body tumor burden. RESULTS:127 consecutive patients were enrolled in the study (69 NF1 patients, 28 NF2 patients, and 30 schwannomatosis patients). The median age was 40years, 43% were male, and median whole-body tumor volume was 26.9mL. There was no relationship between the presence of internal tumors and the presence of detectable S100β in blood for the overall group or for individual diagnoses (p>0.05 by chi-square for all comparisons). Similarly, there was no correlation between whole-body tumor volume and S100β concentration for the overall group or for individual diagnoses (p>0.05 by Spearman for all comparisons). CONCLUSIONS:Plasma S100β is not a useful biomarker for tumor burden in the neurofibromatoses. Further work is needed to identify a reliable biomarker of tumor burden in NF patients.

OBJECTIVE:To determine the prevalence of infection diagnosed by percutaneous computed tomography (CT)-guided sternoclavicular (SC) sampling in cases of suspected joint infection. MATERIALS AND METHODS/METHODS:A retrospective search was performed in reports of SC joint CT-guided biopsies in adults from July 1992 to July 2012. We reviewed medical records, radiology, microbiology, laboratory, and surgical reports. A positive result was defined as demonstration of a pathogenic organism, either by microscopy or growth in culture, confirming the diagnosis of SC joint infection. A negative result was defined as the absence of such findings. Patients in whom sampling was unsuccessful or not subjected to microbiology were excluded. In addition, CT images were reviewed by the consensus of two musculoskeletal radiologists. RESULTS:A total of 41 patients (mean age 57.1 years) underwent CT-guided SC joint sampling, 27 of whom underwent microbiology studies. Sampling was performed using core biopsy alone in 19%, fine needle aspiration alone in 44%, and aspiration combined with core biopsy in 37%. Positive results were found in 52% (14/27) of patients. Related diseases and predisposing conditions for infection were found in 79% of positive patients. Negative results were found in 48% (13/27) of patients. There were no procedure-related complications. The dominant CT findings were soft tissue swelling (negative group), and effusion and/or capsular hypertrophy/distension (positive group). CONCLUSIONS:CT-guided sampling is a safe procedure with positive microbiological cultures in slightly more than half of cases.

Ischiofemoral impingement is a syndrome defined by hip pain associated with narrowing of the space between ischial tuberosity and lesser trochanter. This phenomenon leads to abnormalities of the quadratus femoris muscle, ranging from deformity and edema to tears and atrophy. This review article presents an up-to-date discussion and imaging findings of ischiofemoral impingement, along with its related anatomy, clinical presentation, differential diagnosis and treatment.

Femoroacetabular impingement (FAI) is a common cause of early-onset osteoarthritis of the hip. It can be caused by morphologic abnormalities involving the proximal femur or acetabulum, leading to abnormal abutment of the femoral head-neck against the acetabular rim. This repetitive trauma causes mechanical wear of the labrum and articular cartilage, leading to osteoarthritis of the hip. Magnetic resonance imaging is an accurate noninvasive imaging modality that can detect acetabular labral lesions and adjacent cartilage damage, and is able to detect underlying subtle anatomic variations of the femoral head-neck junction and acetabulum associated with FAI.

BACKGROUND:Vitamin D insufficiency and higher testosterone are common in obese girls and may adversely affect glucose homeostasis and cardiovascular risk. Data are conflicting regarding the impact of parathyroid hormone (PTH) on these factors. Our objective was to determine associations of 25-hydroxyvitamin D (25-OHD), PTH, and testosterone with measures of glucose homeostasis and cardiovascular risk in adolescent girls after controlling for regional adiposity, with the hypothesis that lower 25-OHD, a higher PTH or PTH/25-OHD ratio, and higher testosterone would be associated with lower insulin sensitivity and greater cardiovascular risk. METHODS:A total of 15 obese girls and 15 matched normal weight controls (12-18 years) underwent fasting measurements of 25-OHD, PTH, testosterone, sex hormone-binding globulin (SHBG), high-sensitivity C-reactive protein (hsCRP), oral glucose tolerance testing, and quantification of visceral (VAT) and subcutaneous (SAT) fat by magnetic resonance imaging (MRI). RESULTS:There were no associations of 25-OHD with measures of glucose homeostasis or hsCRP. In contrast, PTH and PTH/25-OHD were associated negatively with homeostasis model assessment of insulin resistance (HOMA-IR) and positively with quantitative insulin sensitivity check index (QUICKI) in obese girls but not controls. These associations remained significant after controlling for body mass index standard deviation score (BMI-SDS), but not for VAT. On regression modeling, PTH/25-OHD was positively associated with hsCRP after controlling for BMI-SDS or VAT. Free testosterone positively predicted the corrected insulin response. CONCLUSIONS:In obese girls, PTH/25-OHD is positively associated with measures of insulin sensitivity and hsCRP. Further studies are needed to investigate the relationship between PTH and glucose homeostasis in obesity.