Byung Se Choi

Intracranial Stenting of Severe Symptomatic Intracranial Stenosis: Results of 100 Consecutive Patients

BACKGROUND AND PURPOSE: There are a few reports regarding the outcome evaluation of balloon-expandable intracranial stent placement (BEICS). The purpose of our study was to evaluate the outcome and factors related to the adverse events (AEs) of BEICS. MATERIALS AND METHODS: We evaluated 100 consecutive patients who underwent BEICS. We assessed the procedural success (residual stenosis <50%), AEs (minor strokes, major strokes, and death), clinical outcome, and restenosis (>50%) at 6 months. We also analyzed 18 factors including symptom patterns related to AE rate. Symptom patterns revealed 1) stable patients (n = 73) with improving, stationary, or resolved symptoms; and 2) unstable patients (n = 27) with gradual worsening or fluctuating symptoms (National Institutes of Health Stroke Scale [NIHSS] ≥4) within 2 days before stent placement. RESULTS: The procedural success rate was 99%. Overall, there were 10 (10%) AEs within the 6 months: 4 (4%) minor strokes, 3 (3%) major strokes, and 3 (3%) deaths including a death from myocardial infarction. AE rate was 4.1% in stable and 25.9% in unstable patients. Restenosis at 6 months revealed 0% (0/59). Good outcome (modified Rankin Scale ≤2) at 6 months was 97% (71/73) in stable and 67% (18/27) in unstable patients. Stepwise logistic regression model revealed that symptom pattern (unstable versus stable) was the only significant risk factor (OR, 8.167; 95% CI, 1.933–34.500; P = .004). CONCLUSION: BEICS revealed a low AE and good outcome rate at 6 months, especially in the stable patients. Midterm outcome was also favorable in the unstable patient group.

Differential Diagnosis of Benign and Malignant Intraductal Papillary Mucinous Tumors of the Pancreas: MR Cholangiopancreatography and MR Angiography

Objective To compare the usefulness of magnetic resonance cholangiopancreatography (MRCP) and MR angiography (MRA) in differentiating malignant from benign intraductal papillary mucinous tumors of the pancreas (IPMTs), and to determine the findings which suggest malignancy. Materials and Methods During a 6-year period, 46 patients with IPMT underwent MRCP. Morphologically, tumor type was classified as main duct, branch duct, or combined. The diameter of the main pancreatic duct (MPD), the extent of the dilated MPD, and the location and size of the cystic lesion, septum, and communicating channel were assessed. For all types of IPMTs, enhanced mural nodules and portal vein narrowing were evaluated at MRA. Results Combined-type IPMTs were more frequently malignant (78%) than benign (42%) (p < 0.05). Compared with benign lesions, malignant lesions were larger, and the caliber of the communicating channel was also larger (p < 0.05). Their dilated MPD was more extensive and of greater diameter (p < 0.05), and the presence of mural nodules was more frequent (p < 0.001). Conclusion Combined MRCP and MRA might be useful for the differential diagnosis of malignant and benign IPMTs of the pancreas.

Angiographic Pattern of Symptomatic Severe M1 Stenosis: Comparison with Presenting Symptoms, Infarct Patterns, Perfusion Status, and Outcome after Recanalization

Background: Several angiographic patterns distal to severe M1 stenosis have been identified. We have assessed the relationship between these angiographic patterns and patient presenting symptoms, infarct patterns, perfusion status and outcome after recanalization. Methods: Three angiographic patterns were retrospectively identified in 60 patients (M:F = 41:19; age range = 34–80 years, mean = 55) who underwent M1 stenting: (1) a normal pattern (n = 22); (2) a shift pattern of the borderzone of the anterior cerebral artery (ACA) and middle cerebral artery (MCA) down to the MCA side with decreased size of MCA branches (n = 16), and (3) a dilatation pattern of the MCA branches with slow flow and minimal shift of borderzone (n = 22). In addition, to analyze interreader agreement, we assessed the correlation between angiographic patterns and gender, presenting symptoms (stroke vs. TIA), infarct patterns on MRI (borderzone vs. non-borderzone infarcts), perfusion results and outcome after stenting by χ2 or Fisher’s exact test. Results: Blind review revealed an excellent interreader agreement in the assessment of angiographic patterns (ĸ = 0.681). The shift pattern was more common in women than in men (p = 0.007). The likelihood of stroke (25/60, 42%, p = 0.001), borderzone infarct (21/32, 66%, p = 0.010) and decreased perfusion (p < 0.001) were greatest in the dilatation pattern, followed by shift and normal patterns. The outcomes did not differ by angiographic pattern probably due to the low event rate (4/60, 6.7%) within 6 months. Conclusions: Patients with severe M1 stenosis had 3 different angiographic patterns, which correlated with presenting symptoms, infarct patterns and perfusion status. Differences in patterns may be related to variation in collateral circulation at the ACA-MCA borderzone and hypoperfusion status.

Detection of residual brain arteriovenous malformations after radiosurgery: diagnostic accuracy of contrast-enhanced three-dimensional time of flight MR angiography at 3.0 Tesla.

Objective Although three-dimensional time-of-flight magnetic resonance angiography (3D TOF-MRA) is used frequently as a follow-up tool to assess the response of arteriovenous malformations (AVMs) after radiosurgery, the diagnostic accuracy of 3D TOF-MRA is not well known. We evaluated the diagnostic accuracy of contrast-enhanced 3D TOF-MRA at 3.0 Tesla for the detection of residual AVMs. Materials and Methods This study included 32 AVMs from 32 patients who had been treated with radiosurgery (males/females: 21/11; average patient age, 33.1 years). The time interval between radiosurgery and MRA was an average of 35.3 months (range, 12-88 months). Three-dimensional TOF-MRA was obtained at a magnetic field strength of 3.0 Tesla after infusion of contrast media, with a measured voxel size of 0.40 × 0.80 × 1.4 (0.45) mm3 and a reconstructed voxel size of 0.27 × 0.27 × 0.70 (0.05) mm3 after zero-filling. X-ray angiography was performed as the reference of standard within six months after MRA (an average of two months). To determine the presence of a residual AVM, the source images of 3D TOF-MRA were independently reviewed, focusing on the presence of abnormally hyperintense fine tangled or tubular structures with continuity as seen on consecutive slices by two observers blinded to the X-ray angiography results. Results A residual AVM was identified in 10 patients (10 of 32, 31%) on X-ray angiography. The inter-observer agreement for MRA was excellent (κ= 0.813). For the detection of a residual AVM after radiosurgery as determined by observer 1 and observer 2, the source images of MRA had an overall sensitivity of 100%/90% (10 of 10, 9 of 10), specificity of 68%/68% (15 of 22, 15 of 22), positive predictive value of 59%/56% (10 of 17, 9 of 16), negative predictive value of 100%/94% (15 of 15, 15 of 16) and diagnostic accuracy of 78%/75% (25 of 32, 24 of 32), respectively. Conclusion The sensitivity of contrast-enhanced 3D TOF-MRA at 3.0 Tesla is high but the specificity is not sufficient for the detection of a residual AVM after radiosurgery.

Treatment Strategy Based on Multimodal Management Outcome of Cavernous Sinus Dural Arteriovenous Fistula (CSDAVF)

Purpose Angiographic finding including venous drainage pattern should be correlated to the presenting symptom pattern (SxP) in CSDAVF. We present outcome of CSDAVF management and suggest a strategy according to SxP and type of treatment based on our experience. Materials and Methods We evaluated SxP, angiographic type (proliferative, restrictive or late restrictive), mode of treatment (embolization, Gamma Knife Radiation (GKR) or conservative management), mode of embolization (transarterial or transvenous), and final clinical status (cure, improvement, aggravation or no change). Ninety consecutive patients were included from a prospective database. The mean follow-up was 17 months. We compared the outcomes according to SxP, angiographic type, mode of treatment, and embolization using the chi-square or Fishers exact test. Results Ninety patients with 34 proliferative, 40 restrictive, and 16 late restrictive types of CSDAVF were treated by embolization (n = 63), GKR (n = 7), and conservative management (n = 20). Cure or improvement was 91% after embolization, 88% after conservative management, and 72% after GKR. Following embolization, 100% of 24 proliferative types, 87% of 30 restrictive types, and 90% of 10 late restrictive types were cured or improved. Cure or improvement after transvenous embolization was 98% (43/44) compared with 88% (15/17) after transarterial embolization (p = 0.003). Conclusion Various factors of SxP, angiographic type, and mode of treatment should be considered in order to obtain a more favorable outcome for patients with CSDAVF. Embolization via venous approach tended to result in a more complete cure than that via arterial approach.

Diagnostic accuracy of ultrasound and 18-F-FDG PET or PET/CT for patients with suspected recurrent papillary thyroid carcinoma.

The purpose of this study was to evaluate the diagnostic accuracies of ultrasound (US) and 18-F-FDG positron emission tomography (PET) or PET/computed tomography (CT) for detecting recurrent papillary thyroid carcinoma (PTC) after total thyroidectomy. Our study enrolled 76 postoperative patients who underwent both neck US and PET because of the suspicion of recurrence. The results of US and PET were correlated with the histopathology, the radioactive iodine whole body scan (WBS) or the clinical follow-up results. Among them, 53 patients had recurrent disease (local recurrence, 42; distant metastasis, 3; elevated Tg level, 8) and 23 showed no evidence of disease. From the analysis, US showed higher diagnostic accuracy, sensitivity and specificity compared with those of PET (71.1%, 71.7% and 69.6% vs. 55.3%, 56.6%, and 52.2%). PET added diagnostic information in a limited number of patients with negative results on neck US (3 with neck recurrence and 2 with distant metastasis).

Use of Self-Expanding Stents for the Treatment of Vertebral Artery Ostial Stenosis: a Single Center Experience

Objective To evaluate our early experience using self-expanding stents to treat atherosclerotic vertebral artery ostial stenosis (VAOS), with respect to technical feasibility and clinical and imaging follow-up results. Materials and Methods A total of 20 lesions in 20 patients underwent stenting of the VAOS using a self-expanding stent (Precise RX; Cordis Neurovascular, Miami Lakes, FL). Two patients were asymptomatic. We analyzed the technical success rate, causes of technical failure, occurrence of any vascular or neurological event, and the occurrence of any neurological abnormality or in-stent restenosis (ISR) seen on follow-up. The imaging follow-up was performed with Doppler ultrasound (DUS) as a primary screening modality. Results One instance of technical failure was caused by failure of the guidewire passage. The stent diameter was 5 mm, and post-stenting balloon dilatations were necessary in all cases. Stent misplacement requiring placement of an additional stent occurred in four cases. Following a 14.8 month average clinical follow-up time, two patients showed anterior circulation ischemia, which was not attributed to the VAOS we treated. Following a 13.7 month average DUS follow-up, five patients showed a mild degree of diffuse or focal intimal thickening in the stent lumen; however, none of the stenosis showed luminal loss of more than 50% and no stent fracture was noted. Conclusion The use of self-expanding stents for treating VAOS was technically feasible and helped to improve artery patency during our limited follow-up interval.

Stent implantation of multichanneled pseudoocclusion of the internal carotid artery.

Multichanneled pseudoocclusion (MCPO) is a severe stenosis with more than 95% of the carotid bulb with multichannels in the stenotic segment. This report describes successful carotid stent implantation in five patients with MCPO of the internal carotid artery. Probing of the micro-guide wire through the channel with support of the microcatheter made subsequent angioplasty and stent placement possible without procedure-related complications. There was neither additional stroke nor restenosis during a follow-up period of 6-54 months.