Isolated calf vein thrombosis: comparison of MR venography and conventional venography after initial sonography in symptomatic patients.

RATIONALE AND OBJECTIVES: The authors performed this study to compare magnetic resonance (MR) venography and conventional venography in the diagnosis of deep venous thrombosis (DVT) in the calf after sonography. MATERIALS AND METHODS: Sonography was performed in 595 patients who were suspected of having lower-extremity DVT. Patients with positive above-knee duplex sonograms, allergy to iodinated contrast material, renal insufficiency, or cardiac pacemakers and patients who were obese were excluded. The remaining 73 patients were asked to undergo MR venography and conventional venography. All studies were to be performed within 48 hours of the clinical diagnosis and according to standard clinical practice. Images were interpreted by radiologists who were blinded to the results of other modalities. Two separate analyses were performed: one in which conventional venography was used as the standard of reference, and one in which the presence of at least two positive studies for thrombus was considered diagnostic. RESULTS: Although 36 patients agreed to participate in the study, only 14 underwent MR venography and conventional venography within 48 hours of the clinical diagnosis. With use of any two positive studies for confirmation, acute DVT was diagnosed in three patients. Conventional venography depicted two of the three cases, whereas sonography and MR venography each depicted all three. The findings were concordant in only five of the 14 patients. CONCLUSION: Moderate discrepancy among modalities was demonstrated. This suggests radiologists should undertake comparisons among these three modalities for the detection of calf DVT. In patients with a high clinical suspicion, a second modality may be useful if the initial study is negative.

Pheochromocytoma crisis, cardiomyopathy, and hemodynamic collapse.

Pheochromocytoma is a notorious clinical entity. Although suspicion is aroused by severe hypertension in young patients, this sign is often absent. We present a case in which early absence of hypertension and nonspecific signs and symptoms led to failure of prompt diagnosis. The delay proved fatal when the patient developed fulminant pheochromocytoma crisis. This case illustrates a variety of clinical features seen from the vantage of the evolution of the disease as it went unrecognized. The patient's course underscores the importance of familiarity with the gamut of manifestations for timely diagnosis, and the priority of the latter given the looming risk of overwhelming complications.

Anticoagulation in dilated cardiomyopathy.

Patients with dilated cardiomyopathy have multiple factors that predispose to thromboembolic events. However, reports of the incidence of thromboembolic events in this population vary widely. There has never been a controlled study of long-term anticoagulation among patients with congestive heart failure due to dilated cardiomyopathy. In this report we review the available published data regarding the risk of thromboembolic events in patients with dilated cardiomyopathy, and the effectiveness and risks of anticoagulation in this population. Although many investigators have called for a prospective, randomized clinical trial to assess the risks and benefits of long-term anticoagulation in patients with dilated cardiomyopathy, a more practical approach may be to compile a national registry of patients with dilated cardiomyopathy to collect observational data on both the rate of embolic events as well as bleeding complications among patients with and without anticoagulation.