Pseudopathologic Brain Parenchymal Enhancement due to Venous Reflux from Left-Sided Injection and Brachiocephalic Vein Narrowing

Abstract

SUMMARY:In this report, we present a case of a patient with CT angiographic artifacts related to left-sided venous injection resulting in a striking pattern of enhancement simulating vascular abnormalities, which prompted additional diagnostic imaging. To our knowledge, no similar case has been reported in the published literature to date. With the development of high-speed multidetector CT units, CT angiography is increasingly becoming a primary tool for evaluation of the vasculature of the head and neck. Although a major advantage is its relative noninvasiveness compared with conventional catheter-based vascular imaging, disadvantages and pitfalls do exist. Failure to recognize these at the time of acquisition and interpretation can lead to poor-quality examinations or, worse, incorrect diagnoses and additional potentially unnecessary imaging or other work-up.We present a case of a patient with artifacts related to leftsided venous injection resulting in a striking pattern of enhancement simulating vascular abnormalities, which prompted additional diagnostic imaging. To our knowledge, no similar case has been reported to date. Case ReportA 59-year-old man with a prior sternotomy for mitral valve repair presented to the emergency department with acutely worsened intermittent vertigo. The possibility of vertebrobasilar ischemia was raised, and a CT angiogram of the neck and head was obtained on a 64-row multidetector CT scanner (Definition; Siemens Medical Systems, Erlangen, Germany) by using a timing bolus triggered from the left internal carotid artery. In this case, venous access was in the left antecubital vein. Contrast injection was 100 mL of iohexol (Omnipaque 350; GE Healthcare, Giles, UK) at 5 mL per second with a 27-second scanning delay.The CT angiogram demonstrated marked parenchymal enhancement in the posterior fossa, medial occipital, and parietal lobes; and opacification of the transverse and sigmoid sinuses and deep venous structures, generally corresponding to posterior circulation territories (Fig 1AϪC). Venous enhancement was also prominent in the left neck more than the right, including the bilateral internal jugular, subclavian, and brachiocephalic veins; the superior vena cava; and the epidural venous plexus and cervical venous plexus, obscuring vertebral artery enhancement. Parenchymal enhancement was evident in the dorsal cervical spinal cord and the left lobe of the thyroid gland. Arterial enhancement in the head and neck was suboptimal, generally less than that of the venous structures detailed above.To evaluate further for structural or vascular abnormalities, we performed an MR imaging of the brain with MR angiography. Contrast-enhanced 3D MR angiography of the neck demonstrated prominent enhancement of the cervical venous plexus on arterial and delayed phases, without a clear vascular malformation or arterial feeder. Findings of brain MR imaging, MR angiography, and MR venography were unremarkable. Findings of conventional angiography were normal. CT angiography of the head and neck ...

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