A rare case of type 2 entrapment of the median nerve after posterior elbow dislocation with MRI and ultrasound correlation.

A 9-year-old boy sustained an ulnohumeral dislocation with a medial epicondyle fracture and experienced incomplete post-traumatic median nerve palsy in addition to post-traumatic stiffness following closed reduction and cast immobilization. When his motor palsy and stiffness did not improve, MRI and ultrasound were obtained, which demonstrated entrapment of the median nerve in an osseous tunnel at the fracture site, compatible with type 2 median nerve entrapment. Subsequently, the patient underwent surgery to mobilize the medial epicondyle and free the median nerve, resulting in improved range of motion, near complete restoration of motor function, and complete restoration of sensory function in the median nerve distribution within 6 months of surgery. Median nerve entrapment, particularly intraosseous, is a rare complication of posterior elbow dislocation and medial epicondyle fracture that may result in significant, sometimes irreversible, nerve damage if there is a delay in diagnosis and treatment. A high degree of clinical suspicion with early imaging is indicated in patients with persistent stiffness or nerve deficits following reduction of an elbow dislocation. Intra-articular entrapment diagnosed on ultrasound has been reported and intraosseous entrapment diagnosed clinically and on MR neurography have been reported; however, to our knowledge, this is the first reported case of intraosseous (type 2) median nerve entrapment clearly visualized and diagnosed on traditional MRI and ultrasound. The use of ultrasound for diagnosing median nerve entrapment is an accurate, accessible, and non-invasive imaging option for patients presenting with suspected nerve entrapment following elbow dislocation.

Clinical utilization of shear wave elastography in the musculoskeletal system.

Shear wave elastography (SWE) is an emerging technology that provides information about the inherent elasticity of tissues by producing an acoustic radiofrequency force impulse, sometimes called an "acoustic wind," which generates transversely-oriented shear waves that propagate through the surrounding tissue and provide biomechanical information about tissue quality. Although SWE has the potential to revolutionize bone and joint imaging, its clinical application has been hindered by technical and artifactual challenges. Many of the stumbling blocks encountered during musculoskeletal SWE imaging are readily recognizable and can be overcome, but progressive advances in technology and a better understanding of image acquisition are required before SWE can reliably be used in musculoskeletal imaging.

Detection of pulmonary embolism during pregnancy: comparing radiation doses of CTPA and pulmonary scintigraphy.

OBJECTIVE: In pregnant patients pulmonary embolism is a common occurrence with potentially devastating outcomes, necessitating timely imaging diagnosis. In every patient, especially in pregnant patients, radiation exposure is an important consideration while selecting the best imaging modality. MATERIALS AND METHODS: We performed a retrospective analysis comparing radiation doses of computed tomography pulmonary angiography (CTPA), perfusion scintigraphy, and perfusion/ventilation scintigraphy for suspected pulmonary embolism in 53 pregnant patients at our hospital between 2006 and 2012. Effective dose and breast-absorbed and uterus-absorbed doses for CTPA as well as effective dose and breast and fetus-absorbed doses for pulmonary scintigraphy were estimated using International Commission on Radiological Protection 103 weighting factors. RESULTS: For CTPA and perfusion scintigraphy, average doses were estimated as effective doses of 21 and 1.04 mSv, breast-absorbed doses of 44 and 0.28 mGy, and uterus-absorbed dose of 0.46 mGy and fetal-absorbed dose of 0.25 mGy, respectively. With inclusion of the ventilation component of pulmonary scintigraphy, doses increased to an effective dose of 1.29 mSv, a breast-absorbed dose of 0.37 mGy, and a fetal-absorbed dose of 0.40 mGy. CONCLUSION: Perfusion nuclear medicine study has a statistically significantly lower effective and breast-absorbed dose (P<0.0001) when compared with CTPA. Similarly, the fetal-absorbed dose for pulmonary scintigraphy has a statistically lower dose (P=0.0010) when compared with CTPA, even if the ventilation component of pulmonary scintigraphy is performed, although these values are so small that they are unlikely to be clinically significant.