The Acutely Limping Preschool and School-Age Child: An Imaging Perspective.

Acute limp in a child presents a diagnostic conundrum and can result from a variety of causes. The underlying etiology is often referable to the hip, but the spine, abdomen, pelvis, or knee can be alternatively implicated. An adequate clinical history and satisfactory physical examination are often difficult in younger children. Consequently, there is disproportionate reliance on imaging to arrive at the correct diagnosis. The potential for rapid clinical deterioration and long-term sequelae is a risk with some of the conditions presenting with acute hip (septic hip, osteomyelitis). This review article describes the imaging appearance of common etiologies for acute limp in the ambulatory preschool (1-5 years) and school-age child (5-12 years). The ultimate goal is to familiarize the interpreting radiologist with the imaging appearance of specific clinical entities that lead to acute limp while providing a readily accessible resource on how to image the patient most appropriately and judiciously.

Doppler Ultrasound Evaluation of Circulatory Support Devices.

In the setting of mechanical circulatory support devices, including ventricular assist devices, extracorporeal membrane oxygenation, intraaortic balloon pumps, and the total artificial heart, the spectral Doppler waveform is significantly altered, reflecting systemic hemodynamic changes. As the prevalence of these devices increases, a better understanding of both the devices themselves and their associated Doppler ultrasound findings is necessary for accurate image interpretation. This article reviews the clinical indications, pathophysiology, and sonographic findings of these devices, with emphasis on the variation in arterial Doppler waveforms that can be seen with normal function, as well as the major complications.

Imaging of Posttraumatic Arthritis, Avascular Necrosis, Septic Arthritis, Complex Regional Pain Syndrome, and Cancer Mimicking Arthritis.

This article focuses on the imaging of 5 discrete entities with a common end result of disability: posttraumatic arthritis, a common form of secondary osteoarthritis that results from a prior insult to the joint; avascular necrosis, a disease of impaired osseous blood flow, leading to cellular death and subsequent osseous collapse; septic arthritis, an infectious process leading to destructive changes within the joint; complex regional pain syndrome, a chronic limb-confined painful condition arising after injury; and cases of cancer mimicking arthritis, in which the initial findings seem to represent arthritis, despite a more insidious cause.

The Best Single Measurement for Assessing Splenomegaly in Patients with Cirrhotic Liver Morphology.

RATIONALE AND OBJECTIVES: There is little agreement within the radiology literature as to the best single measurement for assessing splenomegaly. In this study, we evaluate the correlation of multiple unidirectional measurements of the spleen with splenic volume in patients with cirrhotic liver morphology on computed tomography (CT). MATERIALS AND METHODS: Splenic volume was retrospectively calculated from CT examinations of 179 adult patients, 47 of whom were approved as renal donors, and 132 of whom were referred for various other indications, and were found to have cirrhotic liver morphology on CT. Seven unidimensional measurements (long-axis, cranial-caudal, width, and four measures of thickness) of each spleen were evaluated to identify which most closely correlated with the calculated volume. RESULTS: The splenic width had the best correlation with splenic volume for mild-to-moderate splenomegaly, and the splenic cranial-caudal measurement had the best correlation with splenic volume for massive splenomegaly. Receiver operating characteristic analysis demonstrates that a splenic width measurement of approximately 10.5 cm has a sensitivity of 89% and a specificity of 78% for mild-to-moderate splenomegaly, and a cranial-caudal measurement of 14.6 cm has a sensitivity of 92% and a specificity of 91% for massive splenomegaly. CONCLUSIONS: A splenic width threshold of 10.5 cm is the most sensitive (89%) and specific (78%) single measurement for mild-to-moderate splenomegaly in patients with cirrhotic liver morphology, whereas a cranial-caudal height threshold of 14.6 cm is the most sensitive (92%) and specific (91%) single measurement for massive splenomegaly.

Spectral Doppler ultrasound of peripheral arteries: a pictorial review.

This article reviews the pathophysiology and sonographic findings of peripheral arterial lesions, with emphasis on the spectral Doppler waveforms encountered in each. It discusses the characteristic features of the Doppler spectra in obstructive conditions, including thromboembolism, atherosclerotic disease, bypass graft occlusion, dissection, trauma, and compartment syndrome, as well as non-obstructive conditions, including hyperemia, pseudoaneurysm, and arteriovenous fistula. Familiarity with the commonly-encountered spectral waveforms in the setting of these lesions is necessary for timely and accurate diagnosis and treatment.