Kimihiko Kichikawa

Radiologic placement of side-hole catheter with tip fixation for hepatic arterial infusion chemotherapy.

PURPOSE To investigate the technical outcome of radiologic catheter placement with use of a side-hole catheter with distal fixation for hepatic arterial infusion chemotherapy. MATERIALS AND METHODS Between January 1993 and September 1999, 426 patients were referred to our department to undergo intraarterial infusion chemotherapy for unresectable malignant liver tumors. A subclavian artery was exposed under local anesthesia and a catheter was inserted. After inserting the tip of the side-hole catheter into the gastroduodenal artery, splenic artery, or peripheral branch of the hepatic artery, the catheter tip was fixed to the vessel with use of coils and a mixture of n-butyl cyanoacrylate (NBCA) and iodized oil. The proximal end of the catheter was connected to an implanted port, and the port system was embedded subcutaneously. RESULTS Placement was successful in 425 of 426 patients (99.8%) in a mean time of 76 minutes. Catheter dislodgement was noted in 12 patients (2.8%). Cumulative patency rates of the hepatic artery calculated according to the Kaplan-Meier method for the entire group were 91.0%, 81.4%, and 58.1% at 6 months and 1 and 2 years, respectively. Complications related to catheter placement were observed in nine cases and included dysfunction of the implanted system (n = 3), significant bleeding around the implanted port (n = 2), improper infusion of NBCA and iodized oil (n = 2), and cerebral infarction (n = 2). CONCLUSION Radiologic catheter placement via a subclavian artery with side-hole catheter placement with distal fixation for hepatic arterial infusion chemotherapy is a highly successful procedure with a reduced risk of catheter dislodgment and arterial occlusion.

Pharmacologic Treatment of Intimal Hyperplasia After Metallic Stent Placement in the Peripheral Arteries: An Experimental Study

RATIONALE AND OBJECTIVES.To evaluate the efficacy of oral administration of cilostazol, an antithrombotic agent, for the prevention of thrombotic occlusion and intimal hyperplasia after steanting. METHODS.Single-bodied Z-stents were placed in the iliac arteries of 23 dogs. Before stenting, an embolizing coil was introduced into the right femoral artery to reduce blood flow in the right iliac artery. Eleven dogs were given cilostazol orally, and the other 12 were unmedicated as a control group. The dogs were killed at 4,13, and 24 weeks. RESULTS.Intraluminal narrowing due to thrombus was observed in 25% of dogs in the control group but in none of the dogs in the cilostazol group. The thickness of the neointima was significantly thinner in the cilostazol group than in the control group at 24 weeks on the noncoiled side (P<0.05), and at 4 and 24 weeks on the coiled side (P<0.01). CONCLUSIONS.These results suggest that oral administration of cilostazol is an effective method of preventing thrombotic occlusion and intimal hyperplasia after stenting.

Diffusion Tensor Tractography of the Meyer Loop in Cases of Temporal Lobe Resection for Temporal Lobe Epilepsy: Correlation between Postsurgical Visual Field Defect and Anterior Limit of Meyer Loop on Tractography

BACKGROUND AND PURPOSE: Visual field defects sometimes occur after temporal resection surgery. Our purpose was to evaluate the correlation between visual field defects caused by temporal lobe resection and the degree of resection of the Meyer loop, as assessed by diffusion tensor tractography. MATERIALS AND METHODS: We examined 14 patients who underwent temporal resection for temporal lobe epilepsy. We obtained presurgical tractographies and then measured the distance between the temporal tip and the anterior limit of the Meyer loop (T-M distance). The degree of resection of the Meyer loop was defined as the distance from the anterior limit of the Meyer loop to the posterior limit of the temporal lobe resection (M-R distance). This was calculated by subtracting the T-M distance from the measured distance between the temporal tip and the posterior limit of the resection (T-R distance). RESULTS: The mean T-M distance was 36.6 mm. The interindividual variation of the distance ranged from 30.0 to 43.2 mm. Although there was no statistically significant correlation between the extent of the visual field defect and the T-R distance, there was a statistically significant correlation between the degree of the visual field defect and the M-R distance. CONCLUSION: The range of interindividual variation for the position of the Meyer loop was rather large, indicating that this variation is the key factor in visual field defects after temporal lobectomy, and the visual field defect appears to be predicted by presurgical tractography. Evaluation of the Meyer loop through the use of tractography seems to be a feasible method, which can be used to predict the visual field defect after temporal lobe resection.

Displacement of the facial nerve course by vestibular schwannoma: Preoperative visualization using diffusion tensor tractography

To preoperatively visualize the course of the facial nerve, which is displaced by vestibular schwannoma, using diffusion tensor (DT) tractography, and to evaluate the agreement with surgical findings.

Age correlation of the time lag in signal change on EPI-fMRI

PURPOSE We measured the time lags between the start or end of tasks and signal changes in functional MRI (fMRI) for various age groups and evaluated the age correlation of the time lags. METHODS Forty subjects, 20-76 years old, were evaluated. fMRI was performed with and echo planar imaging sequence at 0.5 s intervals. We measured the time for the signal of the precentral gyrus to make a half-maximal increase after starting the task (T-inc) and the time to reach the initial level after ceasing the task (T-dec). RESULTS Average T-inc was 3.09 s and T-dec was 6.63 s. The values of T-inc could be correlated to age. T-dec had no age correlation. CONCLUSION The time lag in fMRI was revealed to be prolonged with increasing age. Our results suggest that the time lag in fMRI is influenced by some factors associated with aging.

Follow-up Results of 71 Patients Undergoing Metallic Stent Placement for the Treatment of a Malignant Obstruction of the Superior Vena Cava

PurposeTo retrospectively clarify the utility of metallic stent placement for the treatment of the malignant obstruction of the superior vena cava (SVC) in 71 patients with VC syndrome (SVCS) on the basis of long-term follow-up data.Materials and MethodsSeventy-one patients underwent stent placement and were followed until death. The applicability of the spiral Z-stent (S-Z-stent) mainly used the initial and follow-up results, stent placement for bilateral BCV obstruction and the value of concurrent anticancer therapy were studied.ResultsThe technical success rate was 100%, the initial clinical success rate was 87% (62/71), the primary clinical patency rate was 88% (57/65), and the secondary clinical patency rate was 95% (62/65). The obstruction rate of the stent was 12% (8/65), and an additional stent was useful for relief of recurrent SVCS. Survival of 57 patients in whom there was no recurrence of SVCS until death ranged from 1 week to 29 months (mean, 5.4 months and the S-Z-stent appeared to be suitable for the treatment of the malignant obstruction of SVC. Unilateral stent placement was effective for relief of SVCS with bilateral BCV obstruction. Patients who received concurrent anticancer therapy survived 2 months longer than those who did not.ConclusionStent placement is an effective treatment for SVCS. Further, the utility of S-Z-stent for SVCS, an additional stent for recurrence, unilateral stent for patients with bilateral BCV obstruction, and anticancer therapy after stent placement were verified.

Expandable metallic stent placement for nutcracker phenomenon

A 40-year-old woman presented with asymptomatic gross hematuria caused by the nutcracker phenomenon. Despite treatment with hemostatic agents and injection of silver nitrate into the renal pelvis, the hematuria had continued, and severe anemia (hematocrit 17%) had developed. We performed expandable metallic stent (EMS) placement across the left renal vein. Although mild hematuria continued, the anemia resolved after this interventional radiotherapy. EMS placement is a minimally invasive therapy for the nutcracker phenomenon.

Long-term outcomes for systematic primary stent placement in complex iliac artery occlusive disease classified according to Trans-Atlantic Inter-Society Consensus (TASC)-II

PURPOSE To compare long-term outcomes of systematic primary stent placement between Trans-Atlantic Inter-Society Consensus (TASC)-II C/D disease and TASC-II A/B disease. METHODS Between 1997 and 2009, endovascular treatments with primary stent placement were performed for 533 lesions in 413 consecutive patients with iliac artery occlusive disease. Median follow-up term was 72 months (range, 1-144 months). Lesion severity in this retrospective study was classified according to TASC-II as type A in 134 patients (32%), type B in 154 patients (37%), type C in 64 patients (16%), and type D in 61 patients (15%). Technical success rates, procedure time, complication rates, and cumulative primary patency rates were compared between the complex lesion group (TASC-II type C/D) and the simple lesion group (TASC-II type A/B). Risk factors for in-stent restenosis were also analyzed. RESULTS Technical success rates in TASC-II C/D and A/B were both 99%. Procedure times for TASC-II type A, B, C, and D lesions were 98 ± 40, 124 ± 50, 152 ± 55, and 183 ± 68 minutes, respectively. Procedure time was significantly longer in TASC-II C/D (167 ± 63 minutes) than in TASC-II A/B (112 ± 47 minutes; P < .001). The complication rate was significantly higher in TASC-II C/D (9%) than in TASC-II A/B (3%; P = .014). Cumulative primary patency rates at 1, 3, 5, and 10 years were 90%, 88%, 83%, and 71% in TASC-II C/D and 95%, 91%, 88%, and 83% in TASC-II A/B, respectively. No significant differences were apparent between groups (P = .17; Kaplan-Meier method, log-rank test). In multivariate analysis, lesion length was an independent risk factor for in-stent restenosis (hazard ratio, 1.12, P = .03; 95% confidence interval, 1.01-1.24). CONCLUSIONS Primary stent placement for complex iliac artery occlusive disease provides acceptable long-term outcomes, although the procedure takes relatively longer and is associated with a higher frequency of complications than for simple disease.

Characteristic Neuroimaging in Patients with Tumefactive Demyelinating Lesions Exceeding 30 mm

Features of tumefactive demyelinating lesion (TDL) on magnetic resonance imaging (MRI) can facilitate the differential diagnosis of TDL and neoplastic lesions, but vary considerably among patients. The larger TDL grows, the more difficult it becomes to differentiate TDL from neoplastic lesions. The purpose of this study was to elucidate typical MRI features in 12 patients with large TDL (>30 mm in diameter).

Diffusivity and diffusion anisotropy of cerebellar peduncles in cases of spinocerebellar degenerative disease

PURPOSE This study accessed the feasibility of using tractography-based analysis to evaluate the apparent diffusion coefficient (ADC) and fractional anisotropy (FA) of three cerebellar peduncles in subtypes of spinocerebellar degenerative disease. MATERIALS AND METHODS We examined 7 cases of dentatorubro-pallidoluysian atrophy (DRPLA), 4 cases of multiple system atrophy, cerebellar type (MSA-C), 4 cases of late cerebellar cortical atrophy (LCCA) and 8 controls. Diffusion tensor images were obtained, and tractographies of cerebellar peduncles were generated. ADC and FA along the cerebellar peduncles and volume of cerebellar peduncle were measured, and analyses of variance were made among the control and each spinocerebellar degenerative disease groups. RESULTS There were statistically significant decrease in FA and volume and increase in ADC values between DRPLA cases and controls in all three cerebellar peduncles. On the other hand, MSA-C cases mainly showed statistically significant decreased FA and volume and increased ADC values in the middle cerebellar peduncle. LCCA cases did not show prominent difference in the three cerebellar peduncles. CONCLUSION The values of diffusivity and diffusion anisotropy of cerebellar peduncles evaluated by tractography based measurements seem to reflect characteristics of the different types of spinocerebellar degenerative diseases. Tractography-based measurements may be a feasible tool for differential diagnosis of spinocerebellar degenerative disease.