Kensuke Uotani

Dual-energy direct bone removal CT angiography for evaluation of intracranial aneurysm or stenosis: comparison with conventional digital subtraction angiography

Dual-energy CT can be applied for bone elimination in cerebral CT angiography (CTA). The aim of this study was to compare the results of dual-energy direct bone removal CTA (DE-BR-CTA) with those of digital subtraction angiography (DSA). Twelve patients with intracranial aneurysms and/or ICA stenosis underwent a dual-source CT in dual-energy mode. Post-processing software selectively removed bone structures using the two energy data sets. Three-dimensional images with and without bone removal were reviewed and compared to DSA. Dual-energy bone removal was successful in all patients. For 10 patients, bone removal was good and CTA maximum-intensity projection (MIP) images could be used for vessel evaluation. For two patients, bone removal was moderate with some bone remnants, but this did not inhibit the three-dimensional visualization. Three aneurysms adjacent to the skull base were only partially visible in conventional CTA but were fully visible in DE-BR-CTA. In five patients with ICA stenosis, DE-BR-CTA revealed the stenotic lesions on the MIP images. The correlation between DSA and DE-BR-CTA was good (R2=0.822), but DE-BR-CTA led to an overestimation of stenosis. DE-BR-CTA was able to eliminate bone structure using only a single CT data acquisition and is useful to evaluate intracranial aneurysms and stenosis.

Preoperative Visualization of the Artery of Adamkiewicz by Intra-Arterial CT Angiography

BACKGROUND AND PURPOSE: CT and MR angiographies have been reported to visualize the artery of Adamkiewicz (AKA) noninvasively to prevent spinal cord ischemia in surgery of thoracic descending aortic aneurysms. The purpose of this work was to compare the usefulness of CT angiography (CTA) with intra-arterial contrast injection (IACTA) with that of conventional CTA with intravenous contrast injection (IVCTA). MATERIALS AND METHODS: We enrolled 32 consecutive patients with thoracic or thoracoabdominal aortic aneurysms who were scheduled for surgical repair or endovascular stent-graft treatment. All of the CTA images were obtained using a 16-detector row CT scanner and 100 mL of contrast material (370 mg/mL) injected at a rate of 5 mL/s. Contrast was injected via the antecubital veins of 15 patients and via a pig-tail catheter placed at the proximal portion of the descending aorta in 17 patients who underwent IVCTA and IACTA, respectively. Two datasets were reconstructed from 2 consecutive scans. The AKA was identified as a characteristic hairpin curved vessel in the anterior midsagittal surface of the spine and by the absence of further enhancement in the second rather than in the first phase. Continuity between the AKA and aorta was confirmed when the vessel could be traced continuously by paging the oblique coronal multiplanar reconstruction or original axial images. RESULTS: Intra-arterial contrast injection was significantly more sensitive in identifying the AKA than IVCTA: 16 (94.1%) of 17 versus 9 (60.0%) of 15 (P = .033). Continuity between the AKA and aorta through intercostal or lumbar artery was confirmed in 14 (87.5%) of 16 and 5 (55.6%) of 9 of the IACTA and IVCTA groups, respectively. CONCLUSION: Intra-arterial contrast injection detected the AKA at a high rate and verified continuity from the aorta to the AKA.

Leukoaraiosis and hippocampal atrophy predict neurologic outcome in patients who undergo total aortic arch replacement.

BACKGROUND This retrospective study determined whether leukoaraiosis and hippocampal atrophy seen in preoperative magnetic resonance imaging (MRI) predict neurologic outcome after total aortic arch replacement. METHODS From August 2001 to November 2007, 131 consecutive patients (22% women) who underwent elective total arch replacement with selective cerebral perfusion were enrolled. Mean patient age was 71 +/- 17 years (range, 27 to 88 years). On preoperative MRI, mean leukoaraiosis score and hippocampal atrophy score, rated according to the Scheltens scale, were 11.0 +/- 9.2 and 1.5 +/- 1.9, respectively. Forty-three patients (32.8%) had carotid or basilica arterial stenosis, 18 (12.6%) had a stroke, and 6 (4.2%) had a transient ischemic attack. RESULTS One hospital death (0.8%) occurred. Adverse perioperative neurologic events included intraoperative stroke in 8 (6.1%), postoperative stroke in 2 (1.5%), and temporary neurologic dysfunction (TND) in 11 (8.4%). On multivariate logistic regression, significant predictors of postoperative intraoperative stroke were leukoaraiosis (odds ratio [OR], 1.1, p = 0.02) and aortic arch atheroma (OR, 2.4; p = 0.001). TND was significantly associated with leukoaraiosis (OR, 1.1, p = 0.03) and hippocampal atrophy (OR, 1.6, p = 0.01). The best cutoff value for predicting intraoperative stroke was a leukoaraiosis score exceeding 16 (sensitivity, 70%; specificity, 70%); that for predicting TND was a leukoaraiosis score exceeding 18 (sensitivity, 82%; specificity, 77%) and a hippocampal atrophy score exceeding 2 (sensitivity, 82%; specificity, 76%). CONCLUSIONS Leukoaraiosis and hippocampal atrophy are significant independent factors for adverse neurologic outcome after total arch replacement.

Radiologic-Pathologic Correlation of Primary and Secondary Cardiomyopathies: MR Imaging and Histopathologic Findings in Hearts from Autopsy and Transplantation

Cardiac magnetic resonance (MR) imaging with late gadolinium enhancement (LGE) is used to detect and assess the myocardial damage seen with a variety of cardiomyopathies. Gadolinium-based contrast material accumulates in the expanded interstitial space of the myocardium. Areas with LGE correspond to replacement fibrosis, fibrofatty change, epithelioid granuloma, inflammatory cell infiltration, cardiomyocyte necrosis, and amyloid deposition-conditions that represent a focal increase in interstitial space. Areas without LGE correspond to interstitial or plexiform fibrosis, mildly degenerated cardiomyocytes, inflammatory cell infiltration, and diffuse amyloid deposition-conditions that represent diffuse increases in interstitial space. LGE MR imaging cannot depict these diffuse changes and does not enable quantitative evaluation of this increased interstitial space because on inversion-recovery MR images, the inversion time is adjusted to null the signal from normal-appearing or the least enhancing regions of the myocardium. Thus, the absence of LGE does not always indicate normal myocardial tissue. The use of current T1 mapping techniques enables one to overcome these drawbacks of LGE imaging, detect diffuse myocardial abnormalities, and perform quantitative analysis of the interstitial space. The authors describe the histopathologic and corresponding cardiac MR imaging findings of hypertrophic cardiomyopathy, dilated cardiomyopathy, arrhythmogenic right ventricular cardiomyopathy, cardiac sarcoidosis, giant cell myocarditis, and cardiac amyloidosis-mainly those seen on LGE MR images-as assessed by using whole-heart specimens obtained from autopsy or transplantation. ©RSNA, 2017.

Synchrotron radiation coronary microangiography in isolated perfused rat heart for evaluation of coronary vascular response

Visualization of vasoconstriction and vasodilatation of coronary arteries with vasoactive agents is a useful research tool for evaluation of coronary vascular reserve. Microangiography with spatial resolution in the micrometer range was carried out to depict coronary vascular response in a rat heart under Langendorff perfusion using a high-speed imaging system and a third generation synchrotron radiation source at SPring-8. The imaging system was composed of an X-ray direct-conversion type detector incorporating an X-ray SATICON pickup tube and a high-speed X-ray shutter using a galvanometer based scanner. Microangiographic images were obtained without image blur and stored in a digital frame memory system with a 1024/spl times/1024-pixel, 10-bit format. In imaging experiments, the isolated rat heart was mounted on a steel cannula and perfused with oxygenated perfusion fluid. After iodine contrast agent injection into the ascending aorta, vasodilatation in small arteries was visualized in response to acetylcholine.

Endovascular Treatment of Inferior Mesenteric Artery Avulsion Caused by Blunt Abdominal Trauma

performed for an additional 5 minutes. The patient tolerated the procedure well and experienced only mild soreness immediately after the procedure. She was discharged home after 2 hours of standard monitoring in the postanesthesia recovery area. Radiographs of the pelvis 2 weeks after the procedure revealed no abnormalities, and the patient reported complete relief of pain at that time. A focused physical examination was performed to assess pain, proprioception, and sensation with no deficits detected. The patient reported no pain or sensory loss at 2-, 4-, and 6-month follow-up examinations. Follow-up magnetic resonance imaging was not performed because of the benign nature of the tumor and the patient’s excellent clinical response. Treatment of symptomatic benign PNSTs typically involves open surgical resection. Benign PNSTs are slow-growing, often painful tumors. Historically, the treatment of PNST consisted of open surgical resection of the tumor and often portions of the adjacent nerve (2,3). Although surgical resection is the gold standard of care, there are cases in which the location of the PNST precludes open surgery as a reasonable option (4), such as one described here. PNSTs may be divided into benign and malignant subtypes. Schwannomas are a benign variant and may require intervention if they become symptomatic. Pain is typically due to either mass effect compressing the nerve itself or compression against an osseous structure. Although cryoablation performed in nerve-rich areas carries the risk of potential nerve damage and deficits, this case demonstrates cryoablation as a viable technique for definitive treatment of isolated PNSTs.

Prospective comparison of high- and low-spatial-resolution dynamic MR imaging with sensitivity encoding (SENSE) for hypervascular hepatocellular carcinoma

The purpose of this study was to prospectively evaluate the efficacy of high-spatial-resolution dynamic MRI using sensitivity encoding (SENSE) in detection of hypervascular hepatocellular carcinoma (HCC). Thirty-five patients were included in this prospectively planned study, and 25 patients with 31 HCCs were assigned into three groups and underwent the following sequences: group A (n = 11): three-dimensional fast-gradient-echo (3D-FGE) high-spatial-resolution dynamic MRI (HR-MRI) with SENSE; group B (n = 10): 3D-FGE low-spatial-resolution dynamic MRI (LR-MRI) with SENSE; and group C (n = 14): 3D-FGE/LR-MRI without SENSE. For the quantitative analysis, the lesion-to-liver contrast-to-noise ratio (CNR) between the liver and HCCs was measured. For the qualitative analysis, overall image quality for each group was evaluated with a five-point scale analysis. The sensitivities for detection of HCCs were evaluated. The overall image quality in group A was significantly greater than both groups B and C (P < 0.01). The sensitivity of lesion detection on HAP was not significantly higher in group A (100%) than group C (69.2%; P > 0.05). In our pilot study on a small number of patients, image quality in HR-MRI with SENSE was superior to LR-MRI. A high detection rate was seen with HR-MRI with SENSE in the patients with hypervascular HCCs.

Endovascular Aneurysm Repair with Balloon Thrombectomy for Acute Thrombosis of Abdominal Aortic Aneurysm

Acute occlusion of abdominal aortic aneurysm (AAA) is a rare complication and is usually treated with surgical reconstruction. We present a case of acute AAA occlusion that was successfully treated by endovascular aneurysm repair (EVAR) with Fogarty balloon thrombectomy. A 77-year-old man with a history of acute myocardial ischemia presented with limb weakness and coldness. Contrast-enhanced computed tomography showed a 42-mm-diameter infrarenal AAA that was completely thrombosed in the distal portion. The proximal neck of the aneurysm was patent, and its shape was suitable for EVAR. Therefore, we performed balloon thrombectomy of the aortoiliac thrombus that was followed by EVAR. EVAR can be a less invasive alternative than traditional treatment for acute occlusion of AAA.