Cyrus Bateni

Imaging Key Wrist Ligaments: What the Surgeon Needs the Radiologist to Know

OBJECTIVE Although much attention is paid to the scapholunate ligament, lunotriquetral ligament, and the triangular fibrocartilage complex, additional intrinsic and extrinsic ligaments in the wrist play an important part in carpal stability. With improved MRI techniques, the radiologist can increasingly visualize these ligaments. CONCLUSION The anatomy, MRI appearance, and clinical significance of the scapholunate ligament, lunotriquetral ligament, triangular fibrocartilage complex, carpal metacarpal ligaments, and volar and dorsal extrinsic ligaments are reviewed.

Influence of IV Contrast Administration on CT Measures of Muscle and Bone Attenuation: Implications for Sarcopenia and Osteoporosis Evaluation

OBJECTIVE The objective of our study was to characterize enhancement of muscle and bone that occurs on standardized four-phase contrast-enhanced CT. MATERIALS AND METHODS Two musculoskeletal radiologists reviewed standardized four-phase abdominal CT scans obtained with IV contrast material. The psoas area was measured, and the mean attenuation (in Hounsfield units) was recorded for the aorta, psoas muscles, posterior paraspinal muscles, and L4 vertebral body. CT attenuation measures were compared between anatomic regions and imaging phases with the paired t test; associations between measures were examined with the Pearson correlation coefficient (R). RESULTS The study included 201 patients (97 men, 104 women; mean age, 57.7 ± 12.5 [SD] years). Subject age was inversely correlated with unenhanced attenuation in the psoas muscles, posterior paraspinal muscles, and L4 (p < 0.001). The psoas muscles, posterior paraspinal muscles, and L4 enhanced significantly (p < 0.001) at all three contrast-enhanced phases. The greatest muscle enhancement was observed on delayed phase scans, whereas the greatest enhancement in L4 was seen on portal phase imaging. The unenhanced attenuation of the psoas muscles was significantly and negatively correlated with enhancement of the psoas muscles at the portal and delayed phases (p < 0.05 and p < 0.01, respectively), but these correlations were not seen for the posterior paraspinal muscles. Age was positively correlated with posterior paraspinal muscle enhancement at the portal and delayed phases in men (p < 0.05 and p < 0.01, respectively) but not in women. CONCLUSION Contrast enhancement of commonly measured muscle and bone regions is routinely observed and should be considered when using CT attenuation values as biomarkers of sarcopenia and osteoporosis. Furthermore, CT enhancement may be significantly influenced by age, sex, and unenhanced tissue attenuation.

Radiology residents’ experience with intussusception reduction

BackgroundResidents should be exposed to adequate procedural volume to act independently upon completion of training. Informal inquiry led us to question whether residents encounter enough intussusception reductions to become comfortable with the procedure.ObjectiveWe sought to determine radiology residents’ exposure to intussusception reductions, and whether their experiences vary by region or institution.Materials and methodsU.S. radiology residency program directors were asked to encourage their residents to complete a 12-question online survey describing characteristics of their pediatric radiology department, experiences with intussusception reduction, and confidence in their own ability to perform the procedure.ResultsSix hundred sixty-four residents responded during the study period. Of those, 308 (46.4%) had not experienced an intussusception reduction, and 228 (34%) had experienced only one or two. Twenty-two percent of fourth-year residents had never experienced an intussusception reduction, and 21% had experienced only one. Among second- through fourth-year residents, only 99 (18.3%) felt confident that they could competently reduce an intussusception (P < 0.0001), and 336 (62.2%) thought they would benefit from a computer-assisted training model simulating intussusception reduction (P < 0.0001).ConclusionRadiology residents have limited opportunity to learn intussusception reduction and therefore lack confidence. Most think they would benefit from additional training with a computer-simulation model.

CT of Patients With Hip Fracture: Muscle Size and Attenuation Help Predict Mortality.

OBJECTIVE Our objective was to determine the association between muscle cross-sectional area and attenuation, as measured on routine CT scans, and mortality in older patients with hip fracture. MATERIALS AND METHODS A retrospective 10-year study of patients with hip fracture was conducted with the following inclusion criteria: age 65 years or older, first-time hip fracture treated with surgery, and CT of the chest, abdomen, or pelvis. This yielded 274 patients (70.4% women; mean [± SD] age, 81.3 ± 8.3 years). On each CT scan, two readers independently measured the size (cross-sectional area, indexed for patient height) and attenuation of the paravertebral muscle at T12 and the psoas muscle at L4. We then determined the association between overall mortality and the muscle size and muscle attenuation, while adjusting for demographic variables (age, sex, ethnicity, and body mass index), American Society of Anesthesiologists (ASA) classification, and Charlson comorbidity index (CCI). RESULTS The overall mortality rate increased from 28.3% at 1 year to 79.5% at 5 years. Mortality was associated with decreased thoracic muscle size (odds ratio [OR], 0.66; 95% CI, 0.49-0.87). This association persisted after adjusting for demographic variables (OR, 0.69; 95% CI, 0.50-0.95), the ASA classification (OR, 0.70; CI, 0.51-0.97), and the CCI (OR, 0.72; 95% CI, 0.52-1.00). Similarly, decreased survival was associated with decreased thoracic muscle attenuation after adjusting for all of these combinations of covariates (OR, 0.67-0.72; 95% CI, 0.49-0.99). Decreased lumbar muscle size and attenuation trended with decreased survival but did not reach statistical significance. CONCLUSION In older adults with hip fractures, CT findings of decreased thoracic paravertebral muscle size and attenuation are associated with decreased overall survival.

MR Imaging of the Lumbosacral Plexus: A Review of Techniques and Pathologies.

The lumbosacral plexus is a complex anatomic area that serves as the conduit of innervation and sensory information to and from the lower extremities. It is formed by the ventral rami of the lumbar and sacral spine which then combine into larger nerves serving the pelvis and lower extremities. It can be a source of severe disability and morbidity for patients when afflicted with pathology. Patients may experience motor weakness, sensory loss, and/or debilitating pain. Primary neurologic processes can affect the lumbosacral plexus in both genetic and acquired conditions and typically affect the plexus and nerves symmetrically. Additionally, its unique relationship to the pelvic musculature and viscera render it vulnerable to trauma, infection, and malignancy. Such conditions are typically proceeded by a known history of trauma or established pelvic malignancy or infection. Magnetic resonance imaging is an invaluable tool for evaluation of the lumbosacral plexus due to its anatomic detail and sensitivity to pathologic changes. It can identify the cause for disability, indicate prognosis for improvement, and be a tool for delivery of interventions. Knowledge of proper MR protocols and imaging features is key for appropriate and timely diagnosis. Here we discuss the relevant anatomy of the lumbosacral plexus, appropriate imaging techniques for its evaluation, and discuss the variety of pathologies that may afflict it.

The Notch of Harty (Pseudodefect of the Tibial Plafond): Frequency and Characteristic Findings at MRI of the Ankle

OBJECTIVE The purpose of this study is to report the frequency and characteristic findings of the notch of Harty as seen on MRI. MATERIALS AND METHODS One hundred six consecutive ankle MRI studies performed at 1.5 or 3 T were reviewed retrospectively by two radiologists. Findings relating to the notch of Harty and ankle joint were recorded and analyzed, including qualitative assessment of the presence of the notch, focal chondral thinning or focal subcortical osteosclerosis at the notch, notch width and depth, osteochondral lesions elsewhere in the ankle, subchondral edema signal or cystic change at the tibial plafond, and the presence of an ankle joint effusion. RESULTS The study group of 106 patients consisted of 48 male and 58 female patients, with a mean age of 44.5 years (SD, 17.5 years). The notch was identified in 48 of 106 patients (45%) (24 male and 24 female patients; mean age, 43.1 years; range, 7-79 years). When present, the notch averaged 6.2 mm (SD, 1.6 mm) in width and 1.2 mm (SD, 0.5 mm) in depth. The notch was graded as prominent in six of the 106 ankle MRI examinations (6%). Subchondral edemalike signal or cystic change was not localized to the notch in any case. Between patients with versus those without a notch, there was no statistically significant difference in age, sex, subjacent subcortical osteosclerosis, ankle joint effusion, osteochondral lesions elsewhere in the ankle, or subchondral bone marrow edema at the tibial plafond. CONCLUSION The notch of Harty can be observed as an anatomic variant on MRI and should be differentiated from a traumatic osteochondral lesion.

Venous tumor thrombus from a pelvic osteosarcoma

We present a case of pelvic osteosarcoma in an 18-year-old woman with a tumor thrombus in the left iliac vein, extending to the inferior vena cava. Tumor thrombus has been rarely described with osteosarcoma, with only 14 cases in the literature.

Pediatric radiology fellows' experience with intussusception reduction

BackgroundIntussusception reduction allows young children to avoid surgery. However, graduating residents have had relatively little training in intussusception reduction and, for the most part, consider themselves ill-prepared to perform this procedure.ObjectiveThe goal of this study was to assess the extent of training in intussusception reduction during one year of a pediatric radiology fellowship and to determine whether graduating fellows consider themselves adequately trained in this technique.Materials and methodsPediatric radiology fellows were surveyed during June 2010 and asked to characterize their fellowship, to indicate the number of intussusception reductions performed (both the total number and those performed with faculty oversight but without active faculty involvement), and to assess the adequacy of their training.ResultsThere were 31 responses, representing almost 1/3 of current fellows. Pediatric radiology fellows perform on average 6.9 reductions, 3.8 of which are with faculty oversight but without active faculty involvement. Ninety percent consider themselves well-trained in the technique, whereas 10% are uncertain (none consider their training inadequate).ConclusionAlmost all pediatric radiology fellows consider their training in intussusception reduction to be adequate.

Real-time three-dimensional MRI for the assessment of dynamic carpal instability

Carpal instability is defined as a condition where wrist motion or loading creates mechanical dysfunction, resulting in weakness, pain and decreased function. Often the diagnosis is made late when malalignment is visualized on static radiography, CT, or MRI. When conventional imaging methods do not identify the instability patterns, yet clinical signs associated with instability exist, the diagnosis of dynamic instability is often suggested to describe carpal derangement manifested only during the wrist’s active motion or stress. We addressed the question: can advanced MRI techniques provide quantitative measures for evaluating dynamic carpal instability and supplement standard static MRI acquisition? Our objectives were to [1] develop a real-time, three-dimensional MRI method to image the carpal joints during their active, uninterrupted motion; and [2] demonstrate feasibility of the method for assessing metrics relevant to dynamic carpal instability, thus overcoming limitations of conventional MRI. Twenty wrists (bilateral wrists of ten healthy participants) were scanned during radial-ulnar deviation and clenched-fist maneuvers. Images resulting from two real-time MRI pulse sequences, four sparse data acquisition schemes, and three constrained image reconstruction priors were compared. Image quality was assessed via blinded scoring by two radiologists and quantitative imaging metrics. Data acquisition employing sparse radial sampling with a gradient-recalled-echo acquisition and constrained iterative reconstruction (temporal resolution up to 135 ms per slice) appeared to provide a reasonable tradeoff between imaging speed and quality. This real-time MRI method effectively reduced streaking artifacts arising from data undersampling and enabled the derivation of quantitative measures pertinent to evaluating dynamic carpal instability.

Retroperitoneal extramedullary hematopoietic pseudotumor in ataxia–telangiectasia

Ataxia–telangiectasia confers a significant increase in the development of several cancer types, most commonly leukemia and lymphoma. However, as the natural history for these patients is evolving and their lifespan is increasing, there is the potential for the development of additional uncommon tumors in an already rare patient population. We report the first case, to our knowledge, of an incidental retroperitoneal tumor in a 26-year-old woman undergoing evaluation for hepatic dysfunction. The mass was suspicious for retroperitoneal sarcoma, but proved to be an extramedullary hematopoietic pseudotumor after extensive pathologic evaluation. The changing landscape of neoplasms associated with ataxia–telangiectasia is discussed with emphasis on previously underreported benign and malignant tumors.