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Biomedical subjects

Kimihiko Kichikawa

Publications and source records attributed to Kimihiko Kichikawa.

At least 19 recordsLinked to original sources

Pituitary stalk compression by the dorsum sellae: possible cause for late childhood onset growth disorders.

PURPOSE: The purpose of this study was to evaluate the relationship between pituitary stalk compression by the dorsum sellae and clinical or laboratory findings in short stature children. MATERIALS AND METHODS: We retrospectively reviewed magnetic resonance images of the pituitary gland and pituitary stalk for 34 short stature children with growth hormone (GH) deficiency and 24 age-matched control cases. We evaluated the degree of pituitary stalk compression caused by the dorsum sellae. Body height, GH level, pituitary height and onset age of the short stature were statistically compared between cases of pituitary stalk compression with associated stalk deformity and cases without compression. RESULTS: Compression of the pituitary stalk with associated stalk deformity was seen in nine cases within the short stature group. There were no cases observed in the control group. There were no significant differences found for body height, GH level and pituitary height between the cases of pituitary stalk compression with associated stalk deformity and cases without compression. However, a significant difference was seen in the onset age between cases with and without stalk compression. CONCLUSION: Pituitary stalk compression with stalk deformity caused by the dorsum sellae was significantly correlated with late childhood onset of short stature.

Adolescent↗

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

PURPOSE: 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. MATERIALS AND METHODS: The subjects were eight patients with vestibular schwannoma who had undergone removal surgery. DT MR images were obtained and tracts that were considered to represent the facial nerve were constructed. We assessed the success rate for tract construction and evaluated the agreement between tractography findings and surgery. RESULTS: We obtained a tract that connected the internal auditory meatus and brainstem, and was considered to represent the facial nerve in seven of eight cases. The course of the constructed tract agreed with surgical findings in five of these seven cases. One exception was a case in which the tumor was too large to enable intraoperative observation of the facial nerve; however, the facial nerve appeared to be displaced anteriorly at intracapsular resection, in agreement with tractography. In the other case, the schwannoma was mostly cystic. CONCLUSION: Tractographs constructed using MR tensor images enabled us to identify tracts considered to represent facial nerves. We consider DT tractography to be a useful tool for preoperatively predicting facial nerve displacement in vestibular schwannoma.

Adult↗

Malignant duodenal obstructions: palliative treatment using self-expandable nitinol stents.

PURPOSE: To assess the efficacy of fluoroscopic per oral placement of self-expandable nitinol stents in the palliative treatment of malignant duodenal obstructions. MATERIALS AND METHODS: Under fluoroscopic guidance, 82 patients (56 male and 26 female; mean age, 62.3 y) with malignant duodenal obstructions were treated with per oral placement of four types of self-expandable nitinol stents. All patients presented with severe nausea and recurrent vomiting, and their obstructions were inoperable. RESULTS: Technical success was achieved in 78 of 82 patients (95.1%). After stent placement, food intake capacity improved in 74 of 78 patients (94.9%). Stent migration occurred in one patient 4 days after placement. A covered stent was placed to cover the ampulla of Vater in 15 patients without external biliary drainage; three of them (20%) became jaundiced. During the mean follow-up period of 74.7 days (range, 9-374 d), eight patients developed recurrent obstructive symptoms caused by tumor ingrowth (n=2) or tumor overgrowth (n=6). They were successfully treated by additional stent placement. The primary stent patency rates were 97.0%, 79.8%, and 44.0% at 30-, 90-, and 180 days, respectively (mean patency, 228.2 d; 95% CI, 153.9-302.5). CONCLUSIONS: Fluoroscopic per oral placement of self-expandable nitinol stents is an effective palliative treatment for malignant duodenal obstructions.

Adult↗

Usefulness of 16-slice multislice spiral computed tomography for follow-up study of coronary stent implantation.

BACKGROUND: Although multislice spiral computed tomography (MSCT) is a promising technique for non-invasive coronary angiography, its usefulness in patients with stent implantation remains unclear. The aim of the present study was to compare the usefulness of MSCT with that of invasive coronary angiography for evaluating coronary stent patency. METHODS AND RESULTS: Thirty-one patients were enrolled after coronary stent implantation. Sixteen-slice MSCT scans were performed (39.0+/-21.8 days) before follow-up coronary angiography. After assigning an image score based on luminal visibility (1= poor, 2= fair, 3= good), factors determing image quality were analyzed. Among 42 implanted stents, 33 (78%) were assigned an image score of 3, 2 (5%) a score of 2, and 7 (17%) a score of 1. Image scores among stents with diameters >or=3.5 mm were significantly (p<0.05) higher than among smaller stents (<or=3.0 mm). Stent strut thickness did not affect image quality, but coronary calcification significantly (p<0.01) hampered the image quality. After excluding 7 stents with image scores of 1, the sensitivity, specificity, positive and negative predictive values of MSCT to identify patent stents were 83%, 90%, 63% and 96%, respectively. CONCLUSIONS: MSCT can provide useful and valuable clinical information for assessing stent patency during the follow-up period when patients are treated with relatively large diameter coronary stents.

Aged↗

Midterm results of transluminal endovascular grafting in patients with DeBakey type III dissecting aortic aneurysms.

OBJECTIVE: Transluminal endovascular grafting (TEG) is less invasive than conventional operative procedures for the treatment of DeBakey type III dissecting aortic aneurysms (DAA). We have used two different kinds of stent grafts covered with woven Dacron grafts, a Gianturco Z-stent graft (G-SG) and a Spiral Z-stent graft (S-SG). Because the G-SG lacks adequate flexibility, the end of the graft may injure the intima after long-term deployment in the proximal descending aorta. We have used S-SGs, which are more flexible than G-SG, to improve outcome. We report our late midterm results and discuss treatment policy. SUBJECTS AND METHODS: We studied 45 patients with DeBakey type III DAA. Thirty-two G-SGs and 13 S-SGs were used. Follow-up ranged from 1 year 6 months to 8 years 5 months (mean, 5 years 2 months). RESULTS: 1) Surgical outcome: (a) TEG was technically successful in all patients. There was no operative mortality. (b) One week after surgery, 36 patients had no endoleaks, 5 had minor endoleaks, and 4 had major endoleaks. 2) Late midterm results: (a) Four patients with residual major endoleaks, underwent replacement of the descending thoracic aorta. (b) Intimal injury occurred at the distal end of the stent graft 4 to 18 months (mean, 10.5 months) after surgery in 12 patients with G-SG and 1 with S-SG. One of these patients had recurrent dissection, and 12 had ulcer like projections (ULP). Two patients underwent additional stent implantation to block blood flow. (c) Four patients with S-SG had major endoleaks 3 to 6 months after surgery. In 3 of these patients, the Spiral Z-stents were compressed and occluded, and thrombus had formed in the lumen. Three patients underwent replacement of the descending thoracic aorta. (d) Additional replacement of the descending thoracic aorta was done in 9 of the 45 patients (20%) 4 to 24 months after TEG. All patients responded to treatment and were discharged from the hospital. CONCLUSION: Intimal injury was caused by Gianturco Z-stents because of inadequate flexibility, and endoleaks and stent-graft occlusion were caused by Spiral Z-stents because of insufficient radial force against the aortic wall. The development of stents with these improved properties is expected to further improve outcome.

Adult↗

Proton MR spectroscopy of adult-onset dentatorubral-pallidoluysian atrophy.

PURPOSE: To quantify impairment of the basal ganglia (globus pallidus and thalamus) in adult-onset dentatorubral-pallidoluysian atrophy (DRPLA). METHODS: Five patients with genetically definite adult-onset DRPLA (aged 51 to 65 years, mean 55.6 years) and 5 age- and sex-matched healthy controls underwent conventional magnetic resonance imaging (MRI) and proton magnetic resonance spectroscopy (MRS) of the brain in the voxels predominantly containing the globus pallidus or the thalamus. RESULTS: Conventional MRI studies showed apparently normal intensities in the globus pallidus and thalamus. MRS showed that the choline (Cho)/creatine (Cr) ratio for the patients' globus pallidus, the region preferentially affected in DRPLA, was significantly higher than that in the controls (p<0.05). The N-acetylaspartate (NAA)/Cr ratio for the globus pallidus and the Cho/Cr and NAA/Cr ratios for the thalamus, the region relatively spared in this disease, did not differ significantly between the patients and controls. CONCLUSIONS: MRS may sensitively and specifically detect biochemical alterations in susceptible regions of patients with adult-onset DRPLA.

Aged↗

Diffusion tensor imaging in cases with visual field defect after anterior temporal lobectomy.

BACKGROUND AND PURPOSE: Visual defect due to optic radiation injury is a complication of temporal lobectomy for temporal epilepsy. To investigate whether diffusion tensor imaging can delineate the changes in optic radiations after lobectomy, we evaluated parameters on tensor images for optic radiations and correlated them with visual defect. METHODS: We examined 14 cases after temporal lobectomy. Durations after surgeries ranged from 3 weeks to 9 years. The cases were classified into three groups on the basis of the severity of visual field defect (A-C, with group C the most severe). We evaluated signals on T2-weighted images and parameters of tensor images, including fractional anisotropy (FA) and apparent diffusion coefficient (ADC), for the optic radiation in both the operated and intact side. RESULTS: On T2-weighted images, high signals in optic radiations were seen in four cases, occurring more than 4 weeks after surgery. The mean operated-to-intact side FA ratio in the optic radiation decreased according to severity of visual defect (group A, 0.88; group B, 0.89; group C, 0.73). The mean operated-to-intact side ADC ratio showed no significant difference in the overall cases. The ratio for ADC, however, tended to increase according to visual defect in cases after 10 weeks postsurgery. CONCLUSION: Optic radiation showed a decreased FA value in cases after temporal lobectomy. In later stages, ADC values tended to increase and high signal intensities on T2-weighted images were observed. The FA value can be used for evaluating Wallerian degeneration of optic radiation even in the early stages after surgery.

Adult↗

[Extracranial vertebral artery dissection repeating distal embolism: case report].

We report a case of vertebral artery (VA) dissection presenting with repeated distal embolism. A 48-year-old man was admitted to our institution with neck pain and vertigo of two day duration. MRI on arrival showed infarction of the left cerebellar hemisphere and the right occipital lobe. Emergency angiography revealed left VA dissection and occlusion of the left posterior inferior cerebellar artery and right calcaline artery. Six hours after admission, he manifested cortical blindness due to embolism of the contralateral left calcaline artery despite giving heparin and aspirin. Thrombolysis was performed but was not successful. We embolized the affected VA to prevent further embolism. We discuss here the indication and timing of treatment for VA dissection presenting with ischemic symptom.

Blindness, Cortical↗

Signal characteristics of FLAIR related to water content: comparison with conventional spin echo imaging in infarcted rat brain.

To examine the correlation between tissue water content and signal intensity on fluid-attenuated inversion recovery (FLAIR) images, we analyzed infarcted rat brain, verified the results by theoretical simulation, and compared them with conventional spin-echo images. We produced brain infarction with cavitation in five rats by middle cerebral artery occlusion. After in vivo MRI, histologic sections of the MRI plane were obtained. We measured the signal intensity of regions on FLAIR and spin-echo images, and measured the area of cavitation on histologic sections. We plotted curves of cavity percentage to signal intensity. Theoretical values were calculated using a two-compartment model. On the curve of cavity area to signal intensity, the signal on FLAIR images peaked in tissues with 20% to 30% area of cavitation. On the theoretical curve, the signal on FLAIR images peaked at 90% tissue water content. These results seem to be characteristic of FLAIR.

Animals↗

Paradoxical parasellar high signals resembling shunt diseases on routine 3D time-of-flight MR angiography of the brain: mechanism for the signals and differential diagnosis from shunt diseases.

BACKGROUND AND PURPOSE: We occasionally encounter phenomena in which venous flow signals of the cavernous sinus (CS) and/or inferior petrosal sinus (IPS) are visualized paradoxically in patients without arteriovenous shunt in 3D time-of-flight magnetic resonance angiography (3D-TOF MRA) of the brain. The aims of this study are to examine the frequency and cause of this phenomenon ("pseudo-shunt" image) and to determine points of differentiation from definite arteriovenous shunt images ("real shunt"). METHODS: We retrospectively examined 85 maximum intensity projection images obtained by MRA in the absence of arteriovenous shunts to detect pseudo-shunt images, and evaluated source images of pseudo-shunt studies for venous structures. Four real-shunt MRA studies were compared with pseudo-shunt studies on three points: (1) extension of sinuses, (2) extension of cortical veins, and (3) signal intensity of sinuses as assessed by the scoring method (1 point when these findings exist, 0 when they do not). RESULTS: We detected five CS (3%) and six IPS (4%) signals in 9 (11%) of the 85 cases. In the source images of four pseudo-shunt images in the CS, we detected signals from the sphenoparietal sinus (SPS). The average score was significantly lower in the pseudo-shunt (0.22) than the real-shunt (2.75) images (P < .0001). CONCLUSION: In cerebral 3D-TOF MRA, pseudo-shunt images were seen in 11% (9/85) of the study population, with antegrade upward blood flow of the SPS considered as one of the causes. Real-shunt signals can be distinguished from pseudo-shunt signals by evaluation of source images.

Adolescent↗

Catheter position for adequate intra-arterial chemotherapy for advanced pancreatic cancer: evaluation with CT during arterial injection of contrast material.

PURPOSE: To identify the drug infusion vessel for use in obtaining the best drug distribution in arterial infusion chemotherapy for advanced pancreatic cancer. MATERIALS AND METHODS: In 16 cases of advanced pancreatic cancer (pancreatic head, n = 12; pancreatic body and/or tail, n = 4), computed tomography during arterial injection of contrast material was performed at the time of angiography. The sites of catheter placement were celiac artery, superior mesenteric artery, and their branches, such as gastroduodenal artery, inferior pancreatico-duodenal artery, or dorsal pancreatic artery. RESULTS: In the cases of pancreatic head cancer, all except one with hepatomesenteric vascular variation were supplied by the celiac artery and superior mesenteric artery (dual supply). In the cases of pancreatic body and/or tail cancer, two were supplied by celiac artery alone and two showed dual supply. In the cases of pancreatic head cancer, when the areas supplied by the main trunk were compared with those supplied by its branches, three of nine cases on the celiac artery side and four cases on the superior mesenteric artery side showed that the areas were not consistent, with a partial defect observed in the areas supplied by branches of the superior mesenteric artery. In the cases of pancreatic body and/or tail cancer, on both sides, one of two cases was not consistent. CONCLUSIONS: To achieve optimal drug distribution in arterial infusion chemotherapy for advanced pancreatic cancer, drug infusion via both the celiac artery and superior mesenteric artery is required in the majority of cases. In many cases, optimal drug distribution is not attainable with drug infusion via a branch; therefore, drug infusion should be administered via the main trunk.

Adenocarcinoma↗

Distinguishing between anterior cerebral artery and middle cerebral artery perfusion by color-coded perfusion direction mapping with arterial spin labeling.

The purpose of this study was to evaluate collateral circulation by describing anterior cerebral artery and middle cerebral artery perfusion areas. Pairs of image sets spin labeled on the medial and lateral side were used. A pixel-by-pixel t test was performed, with blue gradation used to display lateral perfusion (ie, middle cerebral artery) and orange gradation for anterior cerebral artery perfusion. Extensions of anterior cerebral artery perfusion areas in cases of middle cerebral artery stenosis were described. This method may aid in estimation of collateral circulation for stroke treatment.

Cerebral Angiography↗

[A case of arteriovenous malformation associated with moyamoya phenomenon].

A case with arteriovenous malformation (AVM) associated with moyamoya phenomenon is reported. The 44 year-old female patient was presented with headache and vomiting. Computed tomography (CT) scan showed intraventricular hemorrhage. Cerebral angiography showed right frontal AVM and severe stenosis of right internal carotid artery. The AVM was fed by typical moyamoya vessels, Heubner's artery, and external carotid artery (ECA). We tried to embolize a bleeding point, compartment attached to lateral ventricle, but we could not. So, we embolized feeders from ECA and sent the patient to radiosurgery. We discuss here treatment and etiology of such rare condition.

Adult↗

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.

Adult↗

[Assessment of coronary artery by four-detector multislice computed tomography: diagnostic accuracy and limitations for coronary artery lesions].

OBJECTIVES: The applicability of four-detector multislice computed tomography (MSCT) was investigated for evaluating coronary arteries. METHODS: MSCT (Somatom Volume Zoom, Siemens) was used to evaluate the coronary arteries in 94 patients. The reconstructed images were analyzed using retrospective electrocardiographic gating to determine the image quality of the coronary arteries. In addition, the ability of MSCT to detect coronary artery lesions of > or = 70% (> or = 50% in the left main trunk) diameter stenoses documented by standard coronary angiography was assessed in 67 patients who underwent coronary angiography within the same period. RESULTS: Good image quality was displayed in 488 (58%) and fair in 184 (22%) of a total of 846 coronary segments, but non-assessable in 174 (21%) due to degraded image quality. MDCT detected 33 stenotic lesions correctly in 494 assessable segments, comparable to coronary angiography. The sensitivity and specificity of MSCT were 0.79 and 0.95, respectively. However, an additional 15 lesions were detected by coronary angiography among the non-assessable segments. In total, 24 lesions were missed by MSCT. Accordingly, coronary segments were completely assessable and correctly detected by MSCT in only 20 patients (30%), or 35 (52%) if the distal coronary segments were excluded from analysis. CONCLUSIONS: Four-detector MSCT for detection of coronary artery lesions was applicable to assessable segments. However, clinical use may presently be limited because of the insufficient overall accuracy. Further technical improvement is expected in the near future.

Aged↗