Naoko Nishi

Vertebral artery variations at the C1–2 level diagnosed by magnetic resonance angiography

IntroductionThe craniovertebral junction is clinically important. The vertebral artery (VA) in its several variations runs within this area. We report the prevalence of these VA variations on magnetic resonance angiography (MRA).MethodsWe retrospectively reviewed MRA images, obtained using two 1.5-T imagers, of 2,739 patients, and paid special attention to the course and branching of the VA at the level of the C1–2 vertebral bodies.ResultsThere were three types of VA variation at the C1–2 level: (1) persistent first intersegmental artery (FIA), (2) VA fenestration, and (3) posterior inferior cerebellar artery (PICA) originating from the C1/2 level. The overall prevalence of these three variations was 5.0%. There was no laterality in frequency, but we found female predominance (P < 0.05). We most frequently observed the persistent FIA (3.2%), which was sometimes bilateral. We found VA fenestration (0.9%) and PICA of C1/2 origin (1.1%) with almost equal frequency. Two PICAs of C1/2 origin had no normal VA branch.ConclusionsWe frequently observed VA variations at the C1–2 level and with female predominance. The persistent FIA was most prevalent and sometimes seen bilaterally. Preoperative identification of these variations in VA is necessary to avoid complications during surgery at the craniovertebral junction.

Fenestrations of the intracranial vertebrobasilar system diagnosed by MR angiography

IntroductionFenestrations of cerebral arteries are most common in the vertebrobasilar (VB) system, and magnetic resonance (MR) angiographic studies of these variations are sparse.MethodsWe retrospectively reviewed MR angiographic images of 3,327 patients; images were obtained using two 1.5-T imagers and picked up fenestrations of the intracranial vertebral artery (VA), VB junction, and basilar artery (BA) for evaluation.ResultsIn 92 patients, we found 93 fenestrations (2.80%), which included 18 of the intracranial VA (0.54% prevalence), 6 of the VB junction (0.18%), and 69 of the BA (2.07%). Most VA fenestrations were large, and the posterior inferior cerebellar artery arose from the fenestrated segment in 10 patients (56%). Fenestrations of the VB junction were small and triangular. Sixty-five (94%) of the 69 BA fenestrations were located at the proximal segment and had small slit-like configurations. The anterior inferior cerebellar artery arose from the fenestrated segment in 27 patients (37%). We found 18 cerebral aneurysms in 16 (17%) of the 92 patients with fenestration but detected only one aneurysm at the fenestration.ConclusionThe overall prevalence of fenestrations of the intracranial VB system was 2.77%. We found associated cerebral aneurysms relatively frequently but rarely at the fenestration.

The common hepatic artery arising from the left gastric artery

We report three cases with a rare anatomic variation, in which the common hepatic artery (CHA) arose from the left gastric artery. Fewer than ten cases with this anatomic variation have been published in the literature consulted. In each patient, multidetector-row CT image with 3D reformation demonstrated that the hepatic artery arises from the left gastric artery and runs through the lesser omentum. The left, middle, and right hepatic arteries derived from this artery, and no other arterial supply to the liver was seen. The course of the gastroduodenal artery was variable; it derived from the CHA, the splenic artery, or both. No variation was noted in the splenic artery and the superior mesenteric artery.

Preoperative Transarterial Embolization Enhances the Surgical Management of Diffuse Plexiform Neurofibroma: A Case Report

A 15-year-old boy with neurofibromatosis type-1 (NF-1) presented for management of plexiform neurofibromas in his right arm (Fig. 1). The results of arteriography are shown in Figure 2. Venous return from the tumor was abundant, suggesting ample blood flow. A 3-F microcatheter was super-selectively advanced to the right deep brachial artery and embolization was performed by injecting approximately 20 cubes of 1mm gelatin sponge. Arteriography after embolization demonstrated an obvious decrease in venous return, in addition to a reduction of vascularity in the tumor. The redness of the tumor decreased, and an approximately 15% reduction in tumor volume was observed after embolization. Tumor reduction and suturing were performed under general anesthesia without using an air-tourniquet or xylocaine containing epinephrine. The entire bleeding volume throughout the surgical procedures was less than 10 ml. The excised sample and the local status 4 months after the operation are shown in Figure 3.

Coronary computed tomography angiography using prospective electrocardiography-gated axial scans with 64-detector computed tomography: evaluation of stair-step artifacts and padding time

PurposeWe compared stair-step artifacts and radiation dose between prospective electrocardiography (ECG)-gated coronary computed tomography angiography (prospective CCTA) and retrospective CCTA using 64-detector CT and determined the optimal padding time (PT) for prospective CCTA.Materials and methodsWe retrospectively evaluated 183 patients [mean heart rate (HR) <65 beats/min, maximum HR instability <5 beats/min] who had undergone CCTA. We scored stair-step artifacts from 1 (severe) to 5 (none) and evaluated the effective dose in 53 patients with retrospective CCTA and 130 with prospective CCTA (PT 200 ms, n = 32; PT 50 ms, n = 98).ResultsMean artifact scores were 4.3 in both retrospective and prospective CCTAs. However, statistically more arteries scored <3 (nonassessable) on prospective CCTA (P < 0.001). Mean scores for prospective CCTA with 200- and 50-ms PT were 4.1 and 4.3, respectively (no significant difference). The radiation dose of prospective CCTA was reduced by 59.1% to 80.7%.ConclusionProspective CCTA reduces the radiation dose and allows diagnostic imaging in most cases but shows more nonevaluable artifacts than retrospective CCTA. Use of 50-ms instead of 200-ms PT appears to maintain image quality in patients with a mean HR < 65 beats/min and HR instability of <5 beats/min.

Evaluation of perivalvular infectious ventricular pseudoaneurysm by ECG-gated cardiac computed tomography: 2 case reports.

Left ventricular (LV) pseudoaneurysm is a serious complication of periannular extension of infective endocarditis (IE). Because pseudoaneurysm carries a high risk of rupture, its detection and evaluation are crucial for patient management and surgical planning. We report 2 cases with LV pseudoaneurysms, one near the aortic valve and the other near the mitral valve, which were caused by IE and treated successfully. In both cases, cardiac multidetector-row computed tomography enabled detection of the LV pseudoaneurysm and a detailed demonstration of its anatomic relationship with surrounding structures, which helped guide surgical planning.