Huei-Lung Liang

Multi-detector row computed tomography angiography in diagnosing spinal dural arteriovenous fistula : Initial experience

Background and Purpose— Multi-detector computed tomographic (MDCT) angiography is a recently developed imaging technique that can study small vessels such as medullary arteries and veins. The purpose of this study was to evaluate MDCT angiography in diagnosing SDAVF. Methods— Eight patients with initial magnetic resonance imaging (MRI) and clinical findings suggestive of spinal dural arteriovenous fistula (SDAVF) and 8 control subjects underwent MDCT angiography. Both MDCT angiography and catheter angiography were performed within 5 days in patients with SDAVFs. The results of MDCT angiography in patients with SDAVFs were compared with those of catheter angiography. Results— MDCT angiography detected engorged perimedullary draining veins and correctly localized the fistula of the SDAVFs, and correlated well with catheter angiography. Fistula was at the thoracic level in 7 patients, and sacral level in 1 patient. MDCT angiography did not visualize the engorged perimedullary venous plexus in the control group. Conclusion— MDCT angiography correlated well with catheter angiography in diagnosing SDAVFs. It might play a role in shortening the length of the catheter angiography in diagnosing this disease.

Single-Session Prolonged Alcohol-Retention Sclerotherapy for Large Hepatic Cysts

OBJECTIVE Our purpose was to evaluate the safety and therapeutic efficacy of single-session prolonged alcohol sclerotherapy in treating large hepatic cysts. A therapeutic comparison between 4-hour and 2-hour retention techniques was also studied. MATERIALS AND METHODS Twenty-seven patients with 31 hepatic cysts were enrolled in this study. Seventeen patients (18 cysts) were treated by alcohol retention for 4 hours (group 1) and 10 patients (13 cysts) for 2 hours (group 2). The mean diameter of the hepatic cysts was 12.4 cm (range, 8-23 cm) with a comparable size range in each group. The sclerosing agent used was 95% alcohol, and the maximum amount was limited to 200 mL. Patients changed position and vital signs were monitored every 10-15 minutes. The blood alcohol concentrations were checked hourly for 5 consecutive hours in the initial nine patients. The nonparametric Mann-Whitney U test was used to compare the difference in characteristics and treatment results of the subjects between these two groups. The level of statistical significance was set at a p value of less than 0.05. RESULTS All but one patient in group 2 tolerated the entire course of sclerotherapy. The mean aspirated volume and mean injected alcohol volume of the hepatic cysts were 730 mL and 138.3 mL, respectively, in group 1 patients, and 931 mL and 139 mL, respectively, in group 2 patients. The mean maximum blood alcohol concentration was 128.2 mg/dL (range, 60-199 mg/dL) at 3-4 hours after alcohol instillation. The mean posttherapy residual cystic diameter was 2.5 cm (range, 0-6 cm), with an average volume reduction rate of 98.3% and 97.7%, respectively, for patients in group 1 and group 2 after a mean follow-up period of 29.6 months (9-59 months). No statistical differences of the mean reduction rate between the two groups were noted. CONCLUSION Long retention of the alcohol in a single-injection technique is safe and effective. Two-hour alcohol retention has a comparable efficacy to that of 4-hour retention.

Detection of Subarachnoid Hemorrhage at Acute and Subacute/Chronic Stages: Comparison of Four Magnetic Resonance Imaging Pulse Sequences and Computed Tomography

Background: Acute subarachnoid hemorrhage (SAH) has traditionally been diagnosed by computed tomography (CT); however, fluid‐attenuated inversion recovery (FLAIR) is a magnetic resonance imaging (MRI) modality currently used to detect acute SAH. CT is insensitive in the detection of subacute or chronic SAH. The purpose of this study was to compare 4 MRI pulse sequences and CT in the detection of SAH in acute and subacute‐to‐chronic stages. Methods: From 2001‐2003, we collected data for 22 patients (12 men and 10 women, aged 35‐80 years) with SAH due to ruptured aneurysm (n = 11), trauma (3), or unknown origin (8). All patients underwent MRI and CT examination, with an interval of less than 12 hours between the 2 procedures. We divided patients into 2 groups according to the time from symptom onset to MRI evaluation: patients with MRI performed less than or equal to 5 days post‐ictus had acute‐stage illness, whereas patients with MRI performed from day 6‐30 post‐ictus had a subacute‐to‐chronic condition. MRI (1.5‐T) pulse sequences comprised spin‐echo T1‐weighted, fast spin‐echo T2‐weighted, FLAIR, and gradient‐echo (GE) T2*‐weighted images. Results: In the acute‐stage group, SAH was seen as an area of high signal intensity compared with surrounding cerebrospinal fluid in 36.4% of cases on T1‐weighted images, and in 100% on FLAIR images; low signal intensities were seen in 18.2% of cases on T2‐weighted images, and in 90.9% on GE T2*‐weighted images. High‐attenuated SAH was seen on CT in 90.9% of cases. FLAIR (p = 0.008), GE T2*‐weighted images (p = 0.012) and CT images (p = 0.012) were all statistically significant indicators of acute SAH. In the subacute/chronic‐stage group, SAH was detected on T1‐weighted images (36.4% of cases), FLAIR (33.3%), T2‐weighted images (9.1%), GE T2*‐weighted images (100%), and CT (45.5%). GE T2*‐weighted images were significantly superior (p = 0.001) to other MRI pulse sequences and CT as indicators of subacute‐to‐chronic SAH. Conclusion: FLAIR and GE T2* MRI pulse sequences, and CT scans, are all statistically significant indicators of acute SAH. GE T2*‐weighted images are statistically significant indicators of subacute‐to‐chronic SAH, whereas other MRI pulse sequences, and CT scans, are not.

Intramural Blood Pools Accompanying Aortic Intramural Hematoma: CT Appearance and Natural Course

PURPOSE To evaluate multidetector computed tomographic (CT) images to investigate the prevalence, morphology, natural course, and prognostic effect of intramural blood pools (IBPs) in patients with acute intramural hematoma (IMH). MATERIALS AND METHODS Institutional review board approval and written informed consent were obtained. Sixty-five patients (41 men; mean age, 65.9 years ± 11.3 [standard deviation]) with acute IMH undergoing three or more multidetector CT examinations during follow-up for 12 months or longer (median = 18 months), except for those undergoing surgery (n = 16), were enrolled. Associated factors of developing and resorption of IBP in IMH were analyzed by using logistic regression. RESULTS There were 40 IBPs in 10 patients at initial multidetector CT, and 15 new IBPs developed in 11 patients during follow-up. IBPs occurred most in the descending thoracic (55% [31 of 56]) and abdominal (41% [23 of 56]) aorta in 28% (18 of 65) of patients. During 33.8 months (range, 2.8-50 months) of follow-up in these 18 patients, 57% (32 of 56) of IBPs showed complete resorption in 15 patients, 29% (16 of 56) of IBPs showed incomplete resorption in eight patients, and 14% (eight of 56) of IBPs had interrupted follow-up because of surgery or death in three patients. Logistic regression showed that age younger than 70 years (odds ratio [OR], 8.74; 95% confidence interval [CI]: 1.03, 76.9) and IMH wall thickness greater than 10 mm (OR, 4.93; 95% CI: 1.04, 23.0) were associated with developing IBP at initial multidetector CT, while IBP with larger transmural diameter (OR, 1.16; 95% CI: 1.02, 1.31) and multidetector CT-demonstrated connection with intercostal or lumbar artery (63% [35 of 56]) (OR, 5.44; 95% CI: 1.43, 20.9) were associated with incomplete resorption. CONCLUSION IBPs are frequently observed at multidetector CT in patients with IMH. They may resolve over time or appear during follow-up. These findings are not associated with a poor prognosis, and IBPs should be distinguished from ulcerlike projections.

The Adjunctive Digital Breast Tomosynthesis in Diagnosis of Breast Cancer

Purpose. To compare the diagnostic performance of digital breast tomosynthesis (DBT) and digital mammography (DM) for breast cancers. Materials and Methods. Fifty-seven female patients with pathologically proved breast cancer were enrolled. Three readers gave a subjective assessment superiority of the index lesions (mass, focal asymmetry, architectural distortion, or calcifications) and a forced BIRADS score, based on DM reading alone and with additional DBT information. The relevance between BIRADS category and index lesions of breast cancer was compared by chi-square test. Result. A total of 59 breast cancers were reviewed, including 17 (28.8%) mass lesions, 12 (20.3%) focal asymmetry/density, 6 (10.2%) architecture distortion, 23 (39.0%) calcifications, and 1 (1.7%) intracystic tumor. Combo DBT was perceived to be more informative in 58.8% mass lesions, 83.3% density, 94.4% architecture distortion, and only 11.6% calcifications. As to the forced BIRADS score, 84.4% BIRADS 0 on DM was upgraded to BIRADS 4 or 5 on DBT, whereas only 27.3% BIRADS 4A on DM was upgraded on DBT, as BIRADS 4A lesions were mostly calcifications. A significant P value (<0.001) between the BIRADS category and index lesions was noted. Conclusion. Adjunctive DBT gives exquisite information for mass lesion, focal asymmetry, and/or architecture distortion to improve the diagnostic performance in mammography.

Percutaneous transsplenic catheterization of the portal venous system

Purpose: to evaluate the safety and feasibility of transsplenic portal vein catheterization. Material and Methods: Under ultrasonic guidance, percutaneous transsplenic splenic vein catheterization was performed in 17 patients. Two of the patients had minimal and 5 moderate ascites. in 11 patients, the platelet counts were over 50000/mm3 and the coagulation time normal or mildly prolonged, while 6 patients had either platelet counts of less than 50000/mm3 or moderately prolonged coagulation level. Results: Transsplenic portal catheterizations were successfully performed in 16 of the 17 patients (one failed because of small splenic size). Procedure-related complications occurred in 3 patients with 2 requiring one unit of packed RBC transfusion. the third patient accumulated minimal fluid in the left pleural space. Imaging studies within one week of the procedure were made in 8 patients. These examinations revealed an intrasplenic hematoma in 2 patients. One patient had a small amount of hemoperitone-um. No major complications occurred. Conclusion: Transsplenic portal venous catheterization is a safe and feasible procedure.

Single-session alcohol-retention sclerotherapy for simple renal cysts: comparison of 2- and 4-hr retention techniques.

OBJECTIVE The objectives of our study were to evaluate the feasibility of ethanol sclerotherapy in treating simple renal cysts with prolonged ethanol retention and to compare the therapeutic results of 2- and 4-hr retention techniques. MATERIALS AND METHODS We retrospectively reviewed 36 renal cysts in 33 patients treated by ethanol sclerotherapy with a single-session single-injection technique during the past 6 years. After complete aspiration of the cystic fluid, 95% ethanol was injected into the cyst and was retained for 4 hr in 14 cysts (group 1) and for 2 hr in 22 cysts (group 2). The average maximal diameter and aspirated volume of the cysts were 8.3 cm and 223 mL in group 1 patients and 7.9 cm and 167 mL in group 2, respectively. The ablated cysts were followed up regularly by sonography, CT, or both at 3- to 6-month intervals for at least 1 year. The nonparametric Mann-Whitney U test was used to compare differences in characteristics, treatment results, and laboratory data of the subjects in the two groups. The level of statistical significance was set at a p value of less than 0.05. RESULTS Technically, all the patients tolerated the procedures. One patient had gross hematuria 10 days after the procedure. She underwent surgical deroofing treatment and was excluded in the later statistical analysis. After sclerotherapy, 14 cysts disappeared completely and 16 cysts showed marked regression with residual maximal diameter of less than 3 cm. The overall volume reduction rate was 97.6% in all 35 cysts. The mean residual longest diameters and average volume reduction rates of the treated cysts were 1.9 cm and 97.9% in group 1 patients and 1.1 cm and 97.3% in group 2 patients, respectively, which showed no statistical significance of volume reduction rate with a p value 0.149. CONCLUSION The single-session prolonged ethanol-retention technique is safe and efficacious for the treatment of renal cysts. There is no statistical difference in therapeutic efficacy between 2- and 4-hr ethanol-retention techniques.

Posterior Reversible Encephalopathy Syndrome: Magnetic Resonance Imaging and Diffusion-Weighted Imaging in 12 Cases

Posterior reversible encephalopathy syndrome (PRES) is a potentially devastating neurologic syndrome, but timely treatment may lead to complete reversal of the disease course. We reviewed 12 cases of PRES and describe the clinical history and imaging findings, including conventional magnetic resonance imaging (MRI), diffusion‐weighted imaging (DWI), and calculated apparent diffusion coefficient (ADC) maps, used to establish the diagnosis of PRES. Three male and nine female patients aged between 11 and 70 years (mean, 37 years) with clinical and imaging findings consistent with PRES were enrolled in the study. All patients had undergone conventional MRI and 10 had undergone additional DWI studies. Ten patients had follow‐up MRI studies. DWI was performed using a 1.5T system with a single‐shot spin‐echo echo‐planar pulse sequence. Initial and follow‐up neuroimaging and clinical history were reviewed. Lesions were almost always present over the posterior circulation, mainly the parieto‐occipital region, affecting primarily the white matter. The anterior circulation region, brainstem, cerebellum, deep cerebral white matter, and thalamus were also involved in five cases. Conventional MRI revealed hyperintensity on T2‐ weighted and fluid‐attenuated inversion recovery images. DWI showed isointensity and increased signal intensity on ADC values in all cases, indicating vasogenic edema. Clinical and MRI follow‐up showed that the symptoms and radiologic abnormalities could be reversed after appropriate treatment of the causes of PRES in most patients (9 of 10). In one patient, the ADC value was lower on follow‐up images, indicating cytotoxic edema with ischemic infarct. DWI was a useful complement to MRI in the diagnosis of PRES.

Single-dose time-resolved contrast enhanced hybrid MR angiography in diagnosis of peripheral arterial disease: Compared with digital subtraction angiography

To prospectively study the diagnostic performance of hybrid single‐dose contrast‐enhanced MRA of peripheral arterial disease (PAD), with digital subtraction angiography (DSA) as the reference standard.

A case of spontaneous intracranial hypotension complicated by isolated cortical vein thrombosis and cerebral venous infarction.

Intracranial hypotension is a syndrome of low cerebrospinal fluid (CSF) pressure characterized by postural headache (1). It may occur following lumbar puncture, craniotomy, spinal surgery, or spontaneously – so-called spontaneous intracranial hypotension (SIH). The diagnosis of SIH can be challenging. Recent reports have emphasized intracranial magnetic resonance (MR) findings in SIH (1–4). However, SIH complicated by cerebral sinus venous thrombosis has been mentioned rarely in the literature (5, 6). We present a rare case of SIH complicated by isolated cortical vein thrombosis (ICVT) and cerebral venous infarction. Therapy with epidural blood patch and intravenous heparin was successful.