Obstructive sleep apnea in patients with acute aortic dissection.

BACKGROUND: Obstructive sleep apnea (OSA) imposes an afterload burden on the left ventricle and increases the pressure gradient across the aortic wall. Thus, OSA may increase the risk for aortic dissection (AD). METHODS: This study enrolled 40 subjects with acute AD from four institutions; 37 completed the modified Berlin Questionnaire and 31 underwent attended overnight polysomnography. Aortic diameter was measured on a computed tomography scan at seven locations from the sinotubular junction to the diaphragm. RESULTS: Twenty-seven subjects had type A dissection; 13 had type B. In those who had polysomnography apnea-hypopnea index (AHI) ranged from 0.7 to 89. Prevalence of OSA (AHI ≥ 5) was 61%. Nocturnal presentation (10 p.m.-7 a.m.) did not differ by presence/absence of OSA. The modified Berlin Questionnaire was not predictive of the presence of OSA. Among type A subjects with polysomnography (n = 23), aortic diameters at all locations were greater in the OSA group though differences were not statistically significant. Summating aortic diameters at the seven locations also yielded a numerically larger mean value in the OSA group versus the non-OSA group. CONCLUSIONS: In this sample of patients with acute dissection, OSA was prevalent but was not associated with a nocturnal presentation. The presence of underlying OSA may be associated with larger aortic diameters at the time of dissection compared to patients without OSA. Though differences did not meet statistical significance the current series is limited by small numbers.

Beyond Pulmonary Embolism; Nonthrombotic Pulmonary Embolism as Diagnostic Challenges.

Nonthrombotic pulmonary embolism (NTPE) is less well understood and is encountered less frequently than pulmonary embolism from venous thrombosis. NTPE results from embolization of nonthrombotic material to the pulmonary vasculature originating from many different cell types as well as nonbiologic or foreign materials. For many radiologists NTPE is a challenging diagnosis, presenting nonspecific or unusual imaging findings in the setting of few or unusual clinical signs. The aim of this paper is to review the pathophysiology of diverse causes of NTPE, which should aid radiologists to better understand and, more importantly, diagnose these infrequent events.

Application of 18F-Fluorodeoxyglucose and PET in Evaluation of the Diabetic Foot.

Diagnosing acute and chronic osteomyelitis in the diabetic foot remains a challenge for health care providers. The timely and accurate diagnosis of osteomyelitis has an impact on clinical management of the diabetic foot. Widely used conventional modalities used to noninvasively assess osteomyelitis in the diabetic foot include radiography, MRI, triple-phase bone scintigraphy, and 111-indium-labeled leukocyte imaging. These radiographic and scintigraphic techniques have significant shortcomings. 18F-fluorodeoxyglucose (FDG) PET is increasingly used for the diagnosis of a variety of infectious and inflammatory processes. FDG-PET is an optimal modality for a timely and accurate diagnosis of osteomyelitis as well as for distinguishing it from other pathologic disorders in superficial and deep tissue structures in diabetic patients with a neuropathic foot. This powerful technique is likely to demonstrate greater levels of accuracy than conventional modalities in assessing this complex clinical problem.