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Biomedical subjects

Y Korogi

Publications and source records attributed to Y Korogi.

At least 127 records · Page 7Linked to original sources
PubMed1986

Automatic reregistration for correction of localized misregistration artifacts in digital subtraction angiography of the head and neck.

A new automatic computer program, to remove misregistration artifacts secondary to motions such as rotation, contraction and relaxation of the body, has been developed. This program is called automatic reregistration and consists of determination of distortion vectors of corresponding segments of the mask and live images by detection of the peak value of two-dimensional cross correlation, followed by obtaining distortion vectors of other pixels through interpolation. Shift of the coordinate of the distorted live image is subtracted. Clinical evaluation of this new program, in comparison with already developed remasking and manual reregistration, have proved that some misregistration artifacts, uncorrectable by the latter two methods, have been removed to some extent. The new program has proven to be clinically useful.

Angiography, Digital Subtraction↗
PubMedDate not supplied

III. New developments: 2. Virtual MR endoscopy in the central nervous system.

Recent advances in three-dimensional (3D) data acquisition and postprocessing technologies have been playing a important role in widening the potential applications of 3D display. The authors described new applications of a virtual endoscopic algorithm for 3D display of high resolution MR images: (a) intracranial intravascular virtual MR endoscopy using the 3D fast imaging with steady state precession (FISP) sequence, and (b) virtual MR endoscopy of the cerebrospinal fluid (CSF) spaces using the constructive interference in steady state (CISS) three-dimensional Fourier transform (3DFT) sequence. The virtual endoscopic images were displayed with use of a commercially available perspective volume-rendering algorithm. Our initial experience showed that virtual MR endoscopy can be performed to observe the intracranial arteries and CSF spaces from the viewpoints within themselves. Although the clinical use of the intracranial virtual MR endoscopy has not been established yet, the images obtained are very attractive and further investigations in this field will be expected.

Central Nervous System↗
PubMedDate not supplied

MR findings of Minamata disease--organic mercury poisoning.

We describe MR findings in patients with Minamata disease who have been followed for a long time. All patients examined were affected after daily eating of a large quantity of methylmercury-contaminated seafood, from 1955 to 1958, and showed typical neurological findings. On MR images, the visual cortex, the cerebellar vermis and hemispheres, and the postcentral cortex are significantly atrophic in Minamata disease. The visual cortex is slightly hypointense on T1-weighted images and hyperintense on T2-weighted images, probably representing the pathologic changes of status spongiosus. MRI can demonstrate the lesions located in the calcarine area, cerebellum, and postcentral gyri, which are probably related to three of the characteristic manifestations of this disease: the constriction of the visual fields, ataxia, and sensory disturbance, respectively.

Atrophy↗
PubMedDate not supplied

Ossification of posterior longitudinal ligaments: evaluation with MRI.

Ossification of the posterior longitudinal ligament is a special subcategory of degenerative disease responsible for compression of the spinal cord. On MR images, T2-weighted sequences are the most effective to evaluate both spinal cord compression due to the ossification and abnormal signal intensity of the cord. Although ossification of the ligaments is well demonstrated on CT and plain radiographs, MRI noninvasively provides useful information about the degree and extent of spinal cord compression, as well as the character of the ossification.

Diagnosis, Differential↗
PubMedDate not supplied

Intravascular ultrasound imaging of peripheral arteries as an adjunct to balloon angioplasty and atherectomy.

This article reviews many of the applications of intravascular ultrasound (US) imaging for peripheral arterial diseases. In vitro studies demonstrate an excellent correlation between ultrasound measurements of lumen and plaque cross-sectional area compared with histologic sections. In vivo clinical studies reveal the enhanced diagnostic capabilities of this technology compared with angiography. Intravascular US imaging can provide valuable information on the degree, eccentricity, and histologic type of stenosis before intervention, and on the morphological changes in the arterial wall and the extent of excision after intervention. Intravascular US may also serve as a superior index for gauging the diameter of balloon, stent, laser probe, and/or atherectomy catheter appropriate for a proposed intervention. Significant new insights into the mechanisms of balloon angioplasty and atherectomy have been established by intravascular US findings. Intravascular US imaging has been shown to be a more accurate method than angiography for determining the cross-sectional area of the arterial lumen, and for assessing severity of stenosis. Quantitative assessment of the luminal cross-sectional area after the balloon dilatation should be more accurate than angiography as intimal tears or dissections produced by the dilatation may not be accurately evaluated with angiography. At the present time, intravascular US is still a controversial imaging technique. Outcome studies are currently being organized to assess the clinical value and cost effectiveness of intravascular ultrasound in the context of these interventional procedures.

Angioplasty, Balloon↗
PubMedDate not supplied

Emergency balloon embolization for carotid artery rupture secondary to postoperative infection.

Two cases of carotid artery rupture due to postoperative infection were treated successfully with an emergency endovascular technique. A detachable balloon was attached to a 2 Fr microcatheter and was introduced through a 9 Fr guiding catheter. The balloons were detached at the rupture site and just proximal to the lesion. This technique has several advantages over surgical procedures.

Aged↗
PubMedDate not supplied

Balloon-occluded arterial infusion therapy in the treatment of primary and recurrent gynecologic malignancies.

Balloon-occluded arterial infusion (BOAI) of bilateral internal iliac arteries produces high drug concentration as well as increased arterial flow of pelvic organs. Twenty-seven patients with primary and locally recurrent gynecologic malignancies were treated with BOAI of cisplatinum. Six of 10 patients with primary advanced uterine cancer and 5 of 11 patients with recurrent cancer showed clinical response. In 6 patients, BOAI was performed as an adjuvant therapy to radiation or other chemotherapy. Toxicity was similar to that seen with systemic treatment using cisplatinum, but its frequency and degree were less severe.

Adenocarcinoma↗
PubMedDate not supplied

Intraarterial chemotherapy or chemoembolization for locally advanced and/or recurrent hepatic tumors: evaluation of the feeding artery with an interventional CT system.

PURPOSE: To evaluate the utility of an interventional CT system for intraarterial chemotherapy or chemoembolization for locally advanced and/or recurrent hepatic tumors. METHODS: Thirty-eight patients with locally advanced or recurrent hepatic tumors underwent 73 intraarterial contrast-enhanced CT (IA-CECT) examinations immediately before chemotherapy or chemoembolization. The degree of tumor vascularity on angiography and enhancement on IA-CECT was classified into three grades: no, mild, or marked vascularity. The IA-CECT grades were compared with the angiographic grades. RESULTS: Twenty-nine (69%) of 42 examinations that were interpreted as having no or mild vascularity on angiography were classified as marked enhancement on IA-CECT. Based on IA-CECT findings, the position of the catheter was changed in 14 (19%) of 73 CT examinations. The reasons for the reposition were as follows: weak or no enhancement of the tumor (n = 11) or strong enhancement of the gallbladder wall (n = 3). The treatment strategy was changed in three patients (8%). No major complications relating to the interventional procedures were observed. CONCLUSIONS: IA-CECT is a reliable method when evaluating the perfusion of the tumor and adjacent normal tissues. The interventional CT system is useful for performing safe and effective intraarterial chemotherapy or chemoembolization in patients with locally advanced and/or recurrent hepatic tumors.

Adult↗
PubMedDate not supplied

Stages III and IV squamous cell carcinoma of the mouth: three-year experience with superselective intraarterial chemotherapy using cisplatin prior to definitive treatment.

PURPOSE: This study was designed to assess the 3-year experience with superselective intraarterial chemotherapy prior to definitive treatment for stages III and IV squamous cell carcinomas of the mouth. METHODS: Twenty-two patients prospectively received superselective intraarterial chemotherapy using relatively low-dose cisplatin via a transfemoral approach. The locations of the tumors were the tongue (n = 12), gingiva (n = 5), buccal mucosa (n = 2), hard palate (n = 1), floor of the mouth (n = 1), and lip (n = 1). After intraarterial chemotherapy, 21 patients underwent surgery (n = 14), radiation therapy (n = 6), or both (n = 1). The survival rate of 25 patients who underwent surgery with/without radiation therapy until 1992 at Kumamoto University Hospital was also evaluated as a historical control. The survival curve was calculated with the Kaplan-Meier method, and the statistical difference between survival curves was determined with the generalized Wilcoxon test. RESULTS: The overall response rate was 95% [complete response (tumor completely resolved), 24%; partial response (tumor reduction > or = 50%), 71%]. Fifty-two intraarterial infusions were performed without any catheter-related complications. Mild and transient local toxicity such as edema or mucositis of the infused area was relatively common. One patient died of renal failure from cisplatin. After a median follow-up of 20 months (range 2-41 months), the estimated 3-year survival rate for patients who underwent intraarterial chemotherapy plus surgery was 91%. The survival of the patients who underwent intraarterial chemotherapy plus surgery tended to be longer than that of the historical control. CONCLUSIONS: Early tumor reduction without delay of subsequent treatments can be obtained by intraarterial chemotherapy while minimizing complications and possibly improving survival. Further investigations of long-term survival with larger series need to be performed.

Antineoplastic Agents↗
PubMedDate not supplied

Diagnostic accuracy of intravenous digital subtraction angiography for peripheral vascular diseases.

Intravenous digital subtraction angiography (IV DSA) was performed on 406 regions of 241 patients with peripheral vascular diseases. The results were compared with conventional angiograms for 167 arteries. There was excellent correlation between conventional angiograms and IV DSA. The diagnostic accuracy was 95 with 97% sensitivity and 94% specificity when more than 60% stenoses were taken into consideration. DSA is a less-invasive procedure which can be performed on out-patients for screening and follow-up evaluation of peripheral vascular diseases.

Aged↗
PubMedDate not supplied

Skull base tumors: evaluation with contrast-enhanced MP-RAGE sequence.

The purpose of this study is to assess the value of contrast-enhanced MP-RAGE sequence for evaluation of skull base tumors. A total of 36 patients were prospectively evaluated. MP-RAGE showed relatively higher CNRs than other sequences, and there was a significant difference of CNR between the MP-RAGE and contrast T1-weighted SE images when fat tissue was chosen as the background. MP-RAGE was significantly superior to other sequences in the diagnosis of the extent of tumors. Contrast-enhanced MP-RAGE sequence is useful in evaluation of skull base tumors because of its higher contrast, higher spatial resolution, multiplanar capability, and suppression of the fat signal.

Adolescent↗
PubMedDate not supplied

MR angiography of intracranial aneurysms: a comparison of 0.5 T and 1.5 T.

The objective of this paper is to compare the diagnostic efficacy of 3 DFT time-of-flight MR angiography (MRA) at middle-field-strength and high-field-strength in diagnosis of intracranial aneurysms. Thirty-one patients, including 26 patients with angiographically confirmed intracranial aneurysms (n = 28), underwent MRA at 0.5 and 1.5 T. Images were interpreted by six trained observers who were blinded to diagnosis. Twelve projections of MRA of the circle of Willis, by maximum-intensity projection algorithm, were reviewed using continuous confidence-judgement scales. It was found that MRA at 1.5 T was more sensitive than that at 0.5 T in detection of aneurysms. The sensitivity of six observers ranged between 50 and 64% (mean 56%) at 0.5 T, and between 61 and 86 86% (mean 75%) at 1.5 T. In the smaller aneurysms less than 5 mm, the differences between the units became greater. The sensitivity for small aneurysms ranged from 23 to 54% (mean 32%) at 0.5 T, and from 31 to 69% (mean 58%) at 1.5 T. Our conclusion was that high field strength confers higher accuracy in the detection of intracranial aneurysms with MRA with current-generation MR imagers.

Algorithms↗
PubMedDate not supplied

MR findings of hypoxic damage of the bilateral striate cortices: a case report.

MR imaging of a patient with cortical blindness revealed areas of abnormal signal bilaterally in the lateral putamen and the striate cortices. The coronal T2-weighted image clearly demonstrated the selective involvement of the bilateral striate cortices. The differential diagnosis and the vulnerability of the striate cortex are discussed.

Accidents, Traffic↗
PubMedDate not supplied

Ultrafast FLAIR imaging with single-shot echo-planar technique in evaluation of intracranial lesions.

We evaluated the detection of the brain lesions with single-shot echo-planar FLAIR imaging (EP-FLAIR) relative to fast spin-echo FLAIR imaging (fast-FLAIR). In 30 patients with variety of intracranial lesions, a prospective comparison of EP-FLAIR and fast-FLAIR was performed. Data acquisition time per image was 0.1 s with EP-FLAIR. Quantitative and qualitative criteria as well as lesion detectability were evaluated. EP-FLAIR provided almost same tissue contrast and CSF suppression as fast-FLAIR did. In the quantitative analysis, contrast and contrast-to-noise ratio (C/N) of EP-FLAIR were comparable to those of fast-FLAIR, and there was no significant difference between them. The increased magnetic susceptibility effect was useful in screening for subtle hemorrhage. However, EP-FLAIR was degraded by susceptibility artifacts at the skull base and posterior to the frontal sinuses. Motion artifacts were not encountered owing to the very short imaging time, and EP-FLAIR was particularly useful in screening for the lesions in uncoorporative patients.

Adolescent↗