Between a rock and a hard place: clinical and imaging features of vascular compression syndromes.

Vascular compression syndromes are caused by the entrapment of vessels between rigid or semirigid surfaces in a confined anatomic space. Chronic entrapment may lead to arterial ischemia and embolism, venous stasis and thrombosis, and hematuria. These syndromes are usually seen in otherwise healthy young patients, among whom underdiagnosis is common. Most occurrences of vascular compression are associated with an underlying anatomic abnormality. In a small percentage of cases, other contributing factors, including repetitive microtrauma, may cause pathologic changes leading to the onset of pain and other symptoms of vascular and neural compression. Hence, the diagnosis must be based on both clinical and radiologic findings. Because some cases of vascular entrapment become symptomatic only when specific physical maneuvers are performed, dynamic diagnostic imaging methods are especially useful. Digital subtraction angiography has been the mainstay of imaging-based diagnosis for most vascular compression syndromes, but other methods (eg, color Doppler ultrasonography, computed tomographic angiography, and magnetic resonance angiography) are used with increasing frequency for initial diagnostic evaluation. Because vascular compression syndromes are caused by the external compression of vessels, endoluminal treatment alone is rarely adequate and surgical decompression is likely to be required for optimal and durable clinical benefit. Supplemental material available at http://radiographics.rsna.org/lookup/suppl/doi:10.1148/rg.321115011/-/DC1.