Chung-Wei Lee

Multiphase CT Angiography versus Single-Phase CT Angiography: Comparison of Image Quality and Radiation Dose

BACKGROUND AND PURPOSE: Conventional CT angiography (CTA) is acquired during only a short interval in the arterial phase, which limits its ability to evaluate the cerebral circulation. Our aim was to compare the image quality and radiation dose of conventional single-phase CTA (SP-CTA) with a multiphase CTA (MP-CTA) algorithm reconstructed from a perfusion CT (PCT) dataset. MATERIALS AND METHODS: Fifty consecutive patients undergoing head CTA and PCT in 1 examination were enrolled. The PCT dataset was obtained with 40.0-mm-detector coverage, 5.0-mm axial thickness, 80 kilovolt peak (kVp), 180 mA, and 30 mL of contrast medium. MP-CTA was reconstructed from the same PCT dataset with an axial thickness of 0.625 mm by using a new axial reconstruction algorithm. A conventional SP-CTA dataset was obtained with 0.625-mm axial thickness, 120 kVp, 350 mA, and 60 mL of contrast medium. We compared image quality, vascular enhancement, and radiation dose. RESULTS: SP-CTA and MP-CTA of 50 patients (male/female ratio, 31/19; mean age, 59.25 years) were analyzed. MP-CTA was significantly better than SP-CTA in vascular enhancement (P = .002), in the absence of venous contamination (P = .006), and was significantly higher in image noise (P < .001). MP-CTA used less contrast medium than SP-CTA and could demonstrate hemodynamic information. The effective dose of MP-CTA was 5.73 mSv, which was equal to that in conventional PCT, and it was 3.57 mSv in SP-CTA. CONCLUSION: It is feasible that MP-CTA may provide both CTA and PCT results. Compared with SP-CTA, MP-CTA provides comparable image quality, better vascular enhancement, hemodynamic information, and more noise with less detail visibility with a lower tube voltage. The radiation dose of MP-CTA is higher than that of SP-CTA, but the dose can be reduced by altering the sampling interval.

N-butyl Cyanoacrylate Embolization as the Primary Treatment of Acute Hemodynamically Unstable Lower Gastrointestinal Hemorrhage

PURPOSE To evaluate N-butyl cyanoacrylate (NBCA) embolization as the primary treatment for patients with severe and acute hemodynamically unstable lower gastrointestinal bleeding. MATERIALS AND METHODS Twenty-seven patients with acute, unstable hemodynamics caused by lower gastrointestinal bleeding underwent therapeutic NBCA microcatheter embolization over a period of 27 months. The inclusion criteria were hematochezia or melena and hypotension refractory to conservative treatment and requiring blood transfusion. Bleeding was localized to the rectum, colon, or small intestine in all nine such cases. Fifteen patients had severe underlying comorbidities, including sepsis, respiratory failure, malignancy, or renal failure. RESULTS The procedure was technically successful in all patients. Twenty-six patients were treated solely with NBCA, and one required microcoil embolization. Embolization was performed at the level of the arteria recta or as close as possible to the point of bleeding. Immediate hemostasis occurred in all cases. Four patients experienced repeat hemorrhage, one of whom died. The other three were treated successfully with repeat NBCA embolization. None of the surviving patients had evidence of bowel ischemia. In addition, none of the patients with severe underlying disease died during the follow-up period (range, 3 mo to 2 y). CONCLUSIONS The present findings suggest that NBCA embolization may be a safe alternative treatment for the management of lower gastrointestinal bleeding. Further studies are warranted to confirm the findings.

Intracranial Dural Arteriovenous Fistulas: Diagnosis and Evaluation with 64–Detector Row CT Angiography

PURPOSE To analyze the diagnostic effectiveness and application of computed tomographic (CT) angiography by using a new algorithm (hybrid CT angiography) in dural arteriovenous fistulas (AVFs). MATERIALS AND METHODS Institutional review board approval was obtained for retrospectively postprocessing the raw data from CT angiography by using hybrid CT, which is a mixture of a bone subtraction and masking method for bone removal. The study included 22 patients with 24 dural AVFs and 14 control subjects. The grades in patients with dural AVF determined with hybrid CT angiography and digital subtraction angiography (DSA) were compared, and hybrid CT angiography was applied as a tool for planning endovascular treatment. The adjusted Wald method was used to estimate confidence intervals (CIs), and the Cohen kappa statistic was used to assess interobserver agreement. RESULTS Hybrid CT angiography in the 24 dural AVFs revealed asymmetric sinus enhancement in 22 lesions (92%), engorged arteries in 19 (79%), transosseous enhanced vessels in 19 (79%), engorged extracranial veins in 13 (54%), engorged cortical veins in seven (29%), and sinus thrombosis in four (17%). In all 24 lesions, at least two of six imaging signs for diagnosis of dural AVFs were present. The kappa test analysis revealed a high level of interobserver agreement (kappa, 0.56-1.00) in reading the diagnostic imaging signs. The observed agreement between DSA and readers was 100% in the cavernous sinus region and in hypoglossal and clival lesions and 78%-89% in the transverse sigmoid sinus. The overall sensitivity, specificity, positive predictive value, and negative predictive value were 0.93 (95% CI: 0.85, 0.97), 0.98 (95% CI: 0.93, 1.00), 0.97 (95% CI: 0.90, 0.99), and 0.95 (95% CI: 0.90, 0.98), respectively. CONCLUSION Hybrid CT angiography is a promising tool for the diagnosis of dural AVF. It can provide key information necessary for treatment planning.

Primary adrenal leiomyosarcoma.

Leiomyosarcomas of adrenal origin occur infrequently, always present as huge abdominal masses, and are associated with poor prognoses when other organs are invaded. Radiologic images of small adrenal leiomyosarcomas have not been published. This report presents magnetic resonance images of a 3-cm left adrenal leiomyosarcoma from a 49-year-old male. Ten months after adrenalectomy, the patient was alive without tumor recurrence.

On Concise 3-D Simple Point Characterizations: A Marching Cubes Paradigm

The centerlines of tubular structures are useful for medical image visualization and computer-aided diagnosis applications. They can be effectively extracted by using a thinning algorithm that erodes an object layer by layer until only a skeleton is left. An object point is ldquosimplerdquo and can be safely deleted only if the resultant image is topologically equivalent to the original. Numerous characterizations of 3-D simple points based on digital topology already exist. However, little work has been done in the context of marching cubes (MC). This paper reviews several concise 3-D simple point characterizations in a MC paradigm. By using the Euler characteristic and a few newly observed properties in the context of connectivity-consistent MC, we present concise and more self-explanatory proofs. We also present an efficient method for computing the Euler characteristic locally for MC surfaces. Performance evaluations on different implementations are conducted on synthetic data and multidetector computed tomography examination of virtual colonoscopy and angiography.

Risk profile of patients with poor-grade aneurysmal subarachnoid hemorrhage using early perfusion computed tomography.

OBJECTIVE To determine whether perfusion computed tomography (CT) is useful for identifying patients with poor-grade subarachnoid hemorrhage (SAH) with reversible etiologies and whether early obliteration in patients with poor-grade aneurysmal SAH leads to favorable outcomes. METHODS Patients with new-onset aneurysmal SAH in World Federation of Neurological Surgeons (WFNS) grade IV or V neurologic condition who had perfusion CT performed at admission were eligible for the study. The study retrospectively enrolled 38 patients seen between January 2007 and July 2009. The decision to perform an early obliteration was made by the family after a discussion with the neurosurgeons, neurointensivists, and interventional radiologists. The functional outcomes were correlated with the Glasgow Outcome Scale (GOS) at 6 months, and quantitative perfusion CT data were collected. RESULTS This study included 10 (26%) grade IV and 28 (74%) grade V patients. Favorable outcomes occurred in 19 (50%) patients, and 11 (29%) patients died. After a multivariate logistic regression analysis of the parameters, older age (odds ratio 1.104, P = 0.0317), bilateral prolonged mean transient time (MTT) at the thalami (odds ratio 4.155, P = 0.0362), and early obliteration (odds ratio 0.098, P = 0.003) were predictive of poor outcome. CONCLUSIONS Early bilateral prolonged MTT at the thalami and old age are associated with a poor outcome. Early obliteration benefits a significant portion of SAH patients.

Early parenchymal contrast extravasation predicts subsequent hemorrhage progression, Clinical deterioration, and need for surgery in patients with traumatic cerebral contusion

BACKGROUND This study aimed to identify early radiologic signs that are predictive of hemorrhage progression and clinical deterioration in patients with traumatic cerebral contusion. We hypothesized that contrast extravasation (CE) and blood-brain barrier disruption might be associated with hemorrhage progression, brain edema, and clinical deterioration in these patients. METHODS Twenty-two patients with traumatic cerebral contusion (diagnosed on initial noncontrast head computed tomography [CT]) who initially did not require surgical intervention were enrolled in this study. Contrast-enhanced and perfusion CT scans were performed within 6 hours of injury, and follow-up noncontrast CT scans were performed at 24 hours and 72 hours. RESULTS In each noncontrast CT scan, the volumes of the contusion hemorrhage and edema were calculated using computerized planimetric techniques. The initial Glasgow Coma Scale, hemorrhage progression, clinical deterioration, and the need for subsequent surgery were recorded. The early radiologic findings were compared with these parameters and functional outcome at 6 months to identify predictive radiologic signs. CE was present in 9 of 22 patients (41%) and was highly associated with hemorrhage progression (p < 0.05), clinical deterioration (p < 0.01), and need for subsequent surgery (p < 0.01). In addition, patients with CE had a greater volume of edema at 24 hours (p < 0.01) and 72 hours (p < 0.01) than those who did not have CE. However, CE was not found to be associated with poor outcome. CONCLUSIONS Early parenchymal CE is associated with hemorrhage progression, cerebral edema, clinical deterioration, and need for subsequent surgery. These patients should be monitored closely, and early surgery may be needed if deterioration occurs. Further elucidation of the pathophysiology is needed to formulate effective treatment for these high-risk patients.

Endovascular treatment and computed imaging follow-up of 14 anterior condylar dural arteriovenous fistulas.

We report our experience in treating the anterior condylar dural arteriovenous fistula (DAVF) and confirm the location of the coils in the follow-up images after successful endovascular treatment. We retrospectively reviewed the 14 patients with anterior condylar DAVF treated successfully in our institute. Twelve of them had CT or MR follow-up images. All the patients had intravascular coiling of the fistula. Seven of our patients had retrograde drainage to different sinuses. Three had ocular symptoms as a clinical manifestation. We treated nine patients with coils alone (eight transvenous, one transarterial), four with adjuvant transarterial treatment with particles or liquid embolic for minimal residual after coiling packing. One patient had failed onyx treatment and successful treatment by following transvenous packing. All patients had total obliteration of the DAVF fistula on immediate post-procedure angiogram or on the follow-up images and no evidence of recurrence clinically. The mean follow-up period was 34.2 months (standard deviation=39.8). Twelve patients had computed images (CT alone in four, MR alone in five, both CT and MR in three). These findings were analyzed by four certified neuroradiologists. We found 100% of the coils at the anterior condylar veins inside the hypoglossal canal, 54.2% at the lateral lower clivus, and only 14.2% at the anterior condylar confluence which is ventrolateral to the anterior orifice of the hypoglossal canal. Intravascular coiling is the treatment of choice in patients with anterior condylar DAVF. All the coils were found at the anterior condylar veins inside the hypoglossal canal after successful treatment.

Prospective Comparison of Angio-Seal versus Manual Compression for Hemostasis after Neurointerventional Procedures under Systemic Heparinization

This article addresses the utility of Angio-Seal versus manual hemostasis in anticoagulated patients following neurointerventional procedures. In a study of 174 punctures, 104 were closed with Angio-Seal and the rest with manual compression. All patients had activated clotting time values between 250–500 seconds at the time of closure. Mean hemostasis times were significantly longer with manual compression and hematomas 3 times more common. Using Angio-Seal led to arterial occlusion in 1 patient who was successfully revascularized. Thus, Angio-Seal is fast and effective in this setting. BACKGROUND AND PURPOSE: The use of arterial closure device in patients with prolonged high ACT values has not been extensively studied. The aim of this study was to compare the safety and efficacy of an arterial closure device, Angio-Seal, with manual compression in patients on anticoagulation following neurointerventional procedures. MATERIALS AND METHODS: This was a 2-center prospective study approved by our institutional review boards. In total, 153 consecutive patients with 174 arteriotomies (86 men, 67 women; mean age, 56.1 ± 16.2 years) following femoral arterial puncture for neurointerventional procedures were enrolled in convenience sampling. All of the patients were systemically heparinized with an ACT between 250 and 500 seconds before removal of the sheath after the procedure. Group 1 consisted of 104 arteriotomies that were closed with an arterial closure device (Angio-Seal), and group 2 consisted of 70 arteriotomies treated with manual compression. The ACT before sheath removal, time to hemostasis, and complications immediately and 24 hours after the procedure were recorded. RESULTS: The mean ACT before sheath removal was 284.8 ± 37.6 seconds (range, 250–414 seconds). The mean hemostasis time was significantly shorter in group 1 (2.4 ± 11.7 minutes) compared with group 2 (44.7 ± 27.4 minutes) (95% CI, 38.16–51.24 minutes; P < .001). Hematoma occurred in 9 patients in group 1 (8.6%) and 18 in group 2 (25.7%). One patient developed an arterial occlusion after hemostasis with the closure device, but this was successfully revascularized. CONCLUSIONS: Angio-Seal was found to safely and effectively achieve rapid closure of the femoral access site in patients undergoing neuroendovascular procedures under systemic heparinization with an ACT in the range of 250–500 seconds.

Cerebral Lipiodol Embolism in Hepatocellular Carcinoma Patients Treated with Transarterial Embolization/Chemoembolization.

Background and Purpose Liver cancer is the third leading cause of cancer mortality worldwide. The aim of this study was to investigate the frequency and characteristics of cerebral lipiodol embolism (CLE) in patients with hepatocellular carcinoma (HCC) receiving transarterial embolization/chemoembolization (TAE/TACE). Methods We reviewed all HCC patients who received TAE/TACE during the period of 2007 and 2013 at a university medical center. The frequency of CLE per procedure and the clinical manifestations of CLE, including the review of previous reported cases (n = 24), were analyzed. Results During the study period, a total of 7855 TAE/TACE procedures were conducted on 3277 patients. There were 8 patients (mean age 59±11 years; 5 males and 3 females) who developed CLE. The frequency of TAE/TACE-related CLE was 1.02 (95% CI, 0.44–2.01) per 1000 procedures. Acute disturbance of consciousness and respiratory distress after TAE/TACE were the most common presentations of CLE. All patients had disseminated infarcts involving both the anterior and posterior cerebral circulations. For 3 patients with shunting between the tumor feeding artery and the pulmonary vein, a specific imaging pattern of coexisting scattered hyperdense spots was found. Furthermore, combined with our 8 cases, the total of 32 cases indicated that old age and female sex were the two risk factors for poor outcome after CLE. Conclusions CLE is a rare but potentially serious complication in HCC patients receiving TAE/TACE. The clinical characteristics of CLE summarized in our study would help facilitate the ability of clinicians to provide timely diagnosis and management.