Variations in the origin of the vertebral artery and its level of entry into the transverse foramen diagnosed by CT angiography.

INTRODUCTION: The origin of the vertebral artery (VA) varies, though most VAs enter the transverse foramen (TF) of the sixth cervical vertebra. On computed tomography (CT) angiographic images, we evaluated the prevalence of variations of both VA origin and its level of entry into the TF. METHODS: We retrospectively reviewed CT angiographic images of 2,287 patients obtained using either of two 64-slice multidetector CT scanners. All patients were Japanese and underwent scanning from the aortic arch to the intracranial region; most had or were suspected of having cerebrovascular diseases. RESULTS: The left VA (LVA) arose from the aorta between the left common carotid artery and left subclavian artery in 94 patients (4.1 %) and in other variations in 44 patients (1.9 %). The right VA (RVA) arose from the extreme proximal segment of the right subclavian artery in 72 patients (3.1 %) and in other variations in 14 patients (0.6 %). The LVA entered the sixth TF in 2,127 patients (93.0 %), and the RVA entered the sixth TF in 2,146 patients (93.8 %). Anomalous origin and anomalous entry level into the TF correlated strongly. CONCLUSIONS: The total prevalence of variation in the origin of the LVA was 6.0 % and of the RVA, 3.8 %. The total prevalence of variation in entry level into the TF was 7.0 % for the LVA and 6.2 % for the RVA. Recognition and reporting of these variations is important in interpreting CT angiography to prevent complications during surgery of the aortic arch or lower neck.

Persistent hypoglossal artery and its variants diagnosed by CT and MR angiography.

INTRODUCTION: Persistent hypoglossal artery (PHA) is the second most common anastomosis between the carotid and vertebrobasilar systems and demonstrates some variations. We evaluated the prevalence of PHA on computed tomography (CT) angiography. We also evaluated characteristic features of PHA and its variants on magnetic resonance (MR) angiography. METHODS: We retrospectively reviewed our database of 2,074 CT angiographic images obtained using either of two 64-slice multidetector CT scanners. We also reviewed our database of 7,646 MR angiographic images obtained using either of two 1.5-T or one 3.0-T imager. We could not determine the exact number of patients whose MR angiography included the hypoglossal canal. Most patients had or were suspected of having cerebrovascular diseases. RESULTS: We found six usual PHAs arising from the cervical internal carotid artery on CT angiography among 2,074 patients. On MR angiography, we also found six additional usual PHAs (total 12, right/left = 6/6, male/female = 3/9), three right PHAs originating from the external carotid artery (ECA), and two posterior inferior cerebellar arteries (PICAs) arising from the ECA without connection to the vertebral artery. CONCLUSIONS: The prevalence of usual PHA diagnosed by CT angiography was 0.29 %, slightly higher than that reported for angiography and may be due to selection bias in the examined patients. We propose naming usual PHA "type 1 PHA"; PHA originating from the ECA, of which we found three, "type 2 PHA"; and PICA arising from the ECA, of which we found two, "type 2 PHA variant."

Variation of the origin of the left common carotid artery diagnosed by CT angiography.

INTRODUCTION: The left common carotid artery (LCCA) is usually a second branch of the aortic arch that arises between the brachiocephalic trunk (BCT) and left subclavian artery; relatively frequently, it also arises from or shares a common origin with the BCT. In patients with LCCA of anomalous origin, transfemoral catheterization into the LCCA is sometimes difficult, and transbrachial or transradial approach may be recommended. We evaluated the prevalence of these variations on computed tomography (CT) angiography. METHODS: We retrospectively reviewed CT angiographic images of 2,357 patients obtained using either of two 64-slice multidetector CT scanners. All patients were Japanese and underwent scanning from the aortic arch to the intracranial region; most had or were suspected of having cerebrovascular diseases. RESULTS: We evaluated CT angiographic images of 2,352 patients after excluding four patients with LCCA occluded at its origin. The LCCA arose from the BCT in 141 patients (6.0 %) and had a common origin with the BCT in 130 patients (5.5 %). We found 11 aberrant right subclavian artery (0.47 %), and four of the 11 patients (36 %) had LCCA of common origin with the right common carotid artery, forming a bicarotid trunk (prevalence: 0.17 %). CONCLUSIONS: The total prevalence of variations of LCCA origin diagnosed by CT angiography was 11.7 %.

(1)H MR spectroscopy with external reference solution at 1.5 T for differentiating malignant and benign breast lesions: comparison using qualitative and quantitative approaches.

OBJECTIVE: To compare the diagnostic capability of proton ((1)H) magnetic resonance spectroscopy (MRS) in differentiating benign from malignant breast lesions on the basis of qualitative and quantitative approaches. METHODS: We performed single-voxel (1)H MRS for 208 breast lesions, identified a clear total composite choline compounds (tCho) peak of signal-to-noise of ≥2 to represent malignancy (qualitative approach), and regarded tCho concentration equal to or greater than the cut-off value to represent malignancy (quantitative approach). We compared the diagnostic ability of both approaches using the Akaike information criterion (AIC) and McFadden's R (2). RESULTS: Histologically, 169 lesions were malignant; 39 were benign. The qualitative approach demonstrated 84.6 % sensitivity and 51.3 % specificity for differentiating malignant and benign lesions. The mean tCho concentration was 1.13 mmol/kg for malignancy, 0.43 mmol/kg for benignity. The optimal cut-off point was 0.61 mmol/kg, use of which achieved 68.1 % sensitivity and 79.4 % specificity. Calculated AIC and R (2) score suggested the superiority of the quantitative approach for differentiating malignancy. CONCLUSIONS: Quantitative MRS provides higher specificity than qualitative MRS for differentiating malignant from benign lesions and could be more useful as an additional examination in routine breast MR imaging.

Cushing syndrome treated by radiofrequency ablation of adrenal gland adenoma.

We performed radiofrequency ablation (RFA) in a 35-year-old woman who suffered from Cushing syndrome caused by functioning adenoma of the right adrenal gland. She had a history of tumor enucleation of functioning adenoma of the left adrenal gland 15 years earlier. However, this time she declined repeated surgical intervention. We performed RFA of the right adrenal adenoma, and the lesion was thought to be well ablated. Cortisol levels decreased to below the lower limit of normal after ablation, but recovered to within the normal range after 1 month using steroid substitution therapy. Although hydrocortisone administration was discontinued 18 months after RFA, cortisol levels remained within the normal range for another 2 years in follow-up.

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

INTRODUCTION: The 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). METHODS: We 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. RESULTS: There 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. CONCLUSIONS: We 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.

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.

Fenestrations of the intracranial vertebrobasilar system diagnosed by MR angiography.

INTRODUCTION: Fenestrations of cerebral arteries are most common in the vertebrobasilar (VB) system, and magnetic resonance (MR) angiographic studies of these variations are sparse. METHODS: We 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. RESULTS: In 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. CONCLUSION: The overall prevalence of fenestrations of the intracranial VB system was 2.77%. We found associated cerebral aneurysms relatively frequently but rarely at the fenestration.

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

PURPOSE: We 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 METHODS: We 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). RESULTS: Mean 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%. CONCLUSION: Prospective 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.

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.

[Dual-phase chemical-shift imaging in the detection of diffuse bone metastasis].

Preliminary studies were performed to evaluate the usefulness of lumbar bone marrow MRI using the dual chemical-shift GRE sequence in the detection of diffuse bone metastasis. Two GRE images (TE = 2.3 msec and 4.6 msec) were obtained, and SIR was calculated. SIR was designated as the ratio of in-phase to out-of-phase signal intensity. Among 45 patients with suspicious lumbar bone metastases, diffuse bone metastases were present in 7. Mean SIRs were compared by unpaired t-test. SIRs of diffuse bone metastases had significantly higher signal intensities than those of non-diffuse bone metastases of vertebrae (p < 0.01).

Usefulness of early-phase helical CT for detecting recurrent rectal cancer.

PURPOSE: To evaluate the usefulness of dynamic enhancement of helical CT in the detection of local recurrence of resected rectal cancer. MATERIALS AND METHODS: In 142 patients with a history of curatively resected T2 or T3 rectal cancer, follow-up plain CT indicated that they had a loco-regional recurrent tumor; consequently, they underwent follow-up pelvic helical CT providing accurate early-phase contrast enhancement in the lower pelvic region. The patients were divided into four groups according to the grade of contrast enhancement of the suspected mass-like lesion before and after contrast enhancement, and the correlation between groups and results obtained by biopsy and/or surgery were assessed. If no correlation was found, patients were followed up for a period lasting from 400 days to two years. As of June 2002, results had been obtained for 80 patients, and correlation between these results and grouping by contrast enhancement ratio was analyzed. RESULTS: All patients in the highest-grade group (n=10) had local recurrence. When only the highest-grade group was considered positive, there were no false positives and only one false negative. CONCLUSION: Our results suggest that early-phase contrast enhancement is useful for accurately detecting recurrent rectal cancer. This can be easily achieved using the SmartPrep function, and should be used to distinguish recurrent tumors from postsurgical scar tissue, because these two tissue types do not exhibit similar enhancement patterns.

[The diagnostic imagings of liver metastases].

The liver is an organ susceptible metastases. Malignant neoplasms of many organs frequently metastasize to the liver, particularly colon malignancies. Most metastases enter the liver via the blood circulation, but metastases through lymphatic vessels and the peritoneum are also common. The morphologies of liver metastases and findings on diagnostic images vary considerably. Numerous modalities are available for diagnostic imaging of liver metastases: ultrasonography, computed tomography (CT), magnetic resonance imaging (MRI), angiography, nuclear medicine, and others. Ultrasonography is the simplest, most non-invasive, and cheapest, but relies on the skill of the operator. CT and MRI are also non-invasive, and the sensitivities of these techniques have recently been improved with the development of multidetector CT, contrast agents for MRI that specifically accumulate in the liver, and other advances. Moreover, positron emission CT using fluorine-18-deoxyglucose (FDG-PET) displays a high sensitivity. Angiography is an invasive modality, but is adopted with CT during arterial portography (CTAP) and CT during hepatic arteriography (CTHA), or for the purpose of interventional radiology. Rational selection of appropriate modalities for a given purpose requires familiarity with the characteristics of each modality. In the present paper, we describe the morphologic characters of liver metastases and investigate the associated characteristics and usefulness of each modality.