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T Kozuka

Publications and source records attributed to T Kozuka.

At least 163 records · Page 9Linked to original sources
PubMed1990

Effects of velocity profile of to-and-fro pulsatile flow on magnetic resonance signal intensity.

The effects of to-and-fro pulsatile flow, i.e., an oscillatory fluid motion with no net flow, on signal intensity in gated spin-echo magnetic resonance imaging are considered both theoretically and experimentally. On the basis of hydrodynamic principles, to-and-fro pulsatile flow at large Womersley numbers consists of uniform inner flow and boundary-layer-type flow adjacent to a tube wall. Therefore, the velocity profile is "trapezoidal" rather than parabolic at all times during the pulsation period. Contrary to the absence of phase dispersion and loss of signal within the inner flow where no velocity gradient exists, large velocity differences cause phase dispersion and, hence, loss of signal within the boundary layer, whose thickness is inversely proportional to the Womersley number. An understanding of these features of to-and-fro pulsatile flow provides the theoretical basis of cerebrospinal fluid flow phenomena in magnetic resonance imaging, since this type of flow exists in cerebrospinal fluid pathways.

Cerebrospinal Fluid↗
PubMed1990

Exercise thallium scintigraphy in aortitis syndrome (Takayasu's arteritis).

It is important for patient management to evaluate coronary arterial involvement in aortitis syndrome. Twenty one cases of aortitis syndrome who experienced chest pain were examined using exercise thallium scintigraphy. The patients were divided into four groups according to the angiographic findings. There were: five patients with left main coronary arterial involvement (group A), four with left or right coronary arterial involvement (group B), nine with aortic regurgitation (group C), and three with pulmonary arterial involvement (group D). In group A and B, all patients had positive ECGs and thallium perfusion defects. Group A patients showed extensive anterolateral perfusion defects, which were compatible with left main coronary arterial involvement. Group C and D patients, who had normal coronary arteries, showed no remarkable perfusion defects although five had positive ECG findings. Thus, the sensitivity and specificity of exercise scintigraphy for detection of myocardial ischemia were 9/9 and 12/12, while those of stress ECG were 9/9 and 7/12 (58%), respectively. It is recommended that exercise thallium scintigraphy be used for detecting clinically occult but significant coronary arterial involvement in aortitis syndrome with chest pain.

Adult↗
PubMed1990

Cranial metastasis from hepatocellular carcinoma.

We describe a case of cranial metastasis from an hepatocellular carcinoma studied by computed tomography and cerebral angiography. Although two similar cases have been reported, ours is the first that shows the angiographic findings so clearly and to present with neurological symptoms before primary disease was evident.

Adult↗
PubMed1990

MR imaging of primary pulmonary lymphoma.

We present a patient with primary pulmonary lymphoma studied by magnetic resonance (MR), whose MR appearance was considered to be suggestive of the disorder. On T1-weighted MR images the tumour was seen as a large mass with homogeneous signal intensity, replacing the entire left lower lobe, while on T2-weighted images it was demonstrated as a homogeneous mass with a surrounding thin layer of greater signal intensity. This discrimination was not possible with computed tomography.

Aged↗
PubMed1990

Portal blood flow in congestive heart failure: pulsed duplex sonographic findings.

Twenty-one patients with congestive heart failure were examined with duplex sonographic scanning of the portal vein. The Doppler sonographic findings were compared with those of healthy subjects, patients with chronic liver disease, and patients with Budd-Chiari syndrome. Increasing pulsatility of the Doppler signals was demonstrated in 11 patients with severe congestive heart failure. Two patients with severe congestive heart failure showed decreasing pulsatility of portal Doppler signals in response to therapeutic procedures. Portal flow patterns suggestive of severe congestive heart failure include a monophasic forward flow with peak velocity in ventricular diastole and gradual diminution of velocity throughout ventricular systole (n = 5), a reversed flow velocity in ventricular systole (n = 3), and vena cava-like biphasic forward velocity peaks during each cardiac cycle (n = 2). The time-velocity waveform shape of portal flow is, to a large degree, influenced by the mechanical events in the right side of the heart in severe congestive heart failure.

Blood Flow Velocity↗
PubMed1990

Adverse reactions to ionic and nonionic contrast media. A report from the Japanese Committee on the Safety of Contrast Media.

A large-scale (337,647 cases), nationwide comparative clinical study in Japan on adverse drug reactions (ADRs) to high-osmolar ionic contrast media and low-osmolar nonionic contrast media was performed prospectively. Ionic contrast media were administered in 169,284 cases (50.1%) and nonionic contrast media in 168,363 cases (49.9%). The overall prevalence of ADRs was 12.66% in the ionic contrast media group and 3.13% in the nonionic contrast media group. Severe ADRs occurred in 0.22% of the ionic and 0.04% of the nonionic contrast media examinations. One death occurred in each group, but a causal relationship to the contrast medium could not be established. It is concluded that nonionic contrast media significantly reduce the frequency of severe and potentially life-threatening ADRs to contrast media at all levels of risk and that use of these media represents the most effective means of increasing the safety of contrast media examinations.

Adolescent↗
PubMed1990

Asbestosis: high-resolution CT-pathologic correlation.

High-resolution computed tomography (HRCT) was performed in seven inflated and fixed postmortem lungs from seven asbestos-exposed patients with pathologically proved asbestosis. The parenchymal abnormalities seen at in vitro HRCT included thickened intralobular lines (n = 7), thickened interlobular lines (n = 7), pleural-based opacities (n = 7), parenchymal fibrous bands (n = 5), subpleural curvilinear shadows (n = 4), ground-glass appearance (n = 4), traction bronchiectasis (n = 4), and honeycombing (n = 2). The thickened intralobular lines were shown histologically to be due to peribronchiolar fibrosis. Thickened interlobular lines were due mainly to interlobular fibrotic thickening in four lungs and edema in three. The peribronchiolar fibrosis was most severe in the subpleural lung regions, creating curvilinear line shadows and pleural-based areas of opacity. Some subpleural fibrosis extended proximally along the bronchovascular sheath to create bandlike lesions. Areas of ground-glass appearance on HRCT scans were shown to be the result of mild alveolar wall and interlobular septal thickening due to fibrosis or edema. Postmortem HRCT findings were similar to premortem HRCT findings and correlated well with the pathologic findings of asbestosis.

Aged↗
PubMed1990

CT evaluation of anaplastic thyroid carcinoma.

CT findings in 19 patients with anaplastic thyroid carcinoma were compared retrospectively with pathologic findings and the results of palpation. The carcinoma appeared as a large mass of low attenuation accompanied by dense calcification in 58% of the patients; there was necrosis in 74%. Often, adjacent structures were infiltrated. CT correctly showed tumor invasion of the carotid artery (7/7), internal jugular vein (9/10), larynx (5/6), trachea (8/10), esophagus (4/5), mediastinum (5/5), and regional lymph nodes (14/16). Seven patients (50%) had necrotic nodes. CT was superior to palpation in the detection of a primary tumor in one patient and of metastatic nodes in seven patients. It suggested a suitable place for biopsy in two patients, leading to a correct diagnosis. CT altered surgical planning in five patients with intrathoracic extension of the thyroid tumor, and in three patients with laryngeal or esophageal invasion of the tumor. CT can increase diagnostic accuracy in patients with anaplastic thyroid carcinoma by suggesting a likely diagnosis and by indicating an appropriate site for biopsy. It is indispensable in the planning of surgery for patients with this disorder.

Adult↗
PubMed1990

Percutaneous biopsy of thoracic lesions: value of sonography for needle guidance.

Fluoroscopy and CT are widely used to guide percutaneous needle biopsy of thoracic lesions. However, some lesions are not sufficiently visible on fluoroscopy and others are dangerous to access on CT without real-time monitoring. When these are the circumstances, sonographic guidance may be helpful. Real-time sonography was used to guide percutaneous needle biopsy in 124 patients with thoracic lesions. The indications for sonographic guidance included pulmonary, pleural, or mediastinal lesions in contact with the chest wall, including lesions near the heart or great vessels (n = 12); lesions in the apical region (n = 5); lesions in a juxtadiaphragmatic location (n = 6); small lung nodules adjacent to the chest wall (n = 16); and peripheral tumors with adjacent pleural effusion (n = 4). A diagnosis was made in 74 (90%) of 82 malignant lesions and in 24 (67%) of 36 benign lesions. Complications included pneumothorax (n = 5), hemoptysis (n = 1), and hemothorax (n = 1). The advantages of sonographic guidance are that the sonographic equipment is mobile and real-time monitoring makes the procedure safer. Its limitations are that it cannot be used when aerated lung or free air (pneumothorax) lies between the chest wall and the lesion and that cavitary lesions are difficult to sample by biopsy. Our results show that the use of sonographic guidance considerably expands the number of thoracic lesions amenable to percutaneous biopsy.

Biopsy, Needle↗
PubMed1990

Regenerating nodules in hepatic cirrhosis: MR findings with pathologic correlation.

To establish clearly the pathologic basis for small low-intensity nodules seen on MR images of the cirrhotic liver, we obtained MR images in 26 patients with cirrhosis in whom partial hepatectomy for hepatoma (15 patients), laparoscopy for cirrhosis (10 patients), or autopsy (one patient) was subsequently performed. Small low-intensity nodules were seen on gradient-echo images with short TEs (10-13 msec) in 13 of the 26 patients. In 12 of these 13 patients, small low-intensity nodules appeared larger and clearer as the TE was prolonged (14-25 msec). On T2-weighted spin-echo images, small low-intensity nodules were seen in 12 of the 13 patients, but not seen as well as on gradient-echo images. Pathologic correlation in these 13 patients revealed that the nodules on the MR images corresponded to iron deposits in regenerating nodules. Small low-intensity nodules were observed only on T2-weighted spin-echo images in two of the remaining 13 patients, in whom microscopic examination of the liver revealed marked inflammatory cell infiltration in the fibrous septa and no iron deposition. We conclude that small low-intensity nodules observed on MR images are caused by iron deposits in regenerating nodules, and that gradient-echo images with short and prolonged TEs are useful to confirm the presence of iron deposits in regenerating nodules.

Adult↗
PubMed1990

Computed tomographic arteriography of the liver using balloon occlusion.

The article describes a new method for computed tomographic arteriography (CTA) of hepatocellular carcinoma (HCC) using a balloon occlusion catheter in 8 patients. Our dynamic study indicated that: 1) a bolus injection of contrast medium with our method of CTA (CTA-B) produced an attenuation difference between liver and tumor which was about double that obtained with standard methods for CTA, and 2) marked tumor-liver attenuation differences (above 20 HU) persisted for more than 60 s in CTA-B and for not more than 20 s with conventional methods for CTA. The results show that CTA-B is superior to standard methods in enabling multiple scans of the liver during greater and prolonged differential tumor enhancement after administration of a bolus of contrast medium. In conjunction with table incrementation, CTA-B allows scanning of the entire liver at the time of maximal contrast enhancement with two to three injections of contrast medium. Two patients complained of abdominal pain during balloon inflation. No other complications were observed.

Carcinoma, Hepatocellular↗
PubMed1990

[MRI of hepatocellular carcinoma--the intensity changes after TCE].

Magnetic resonance (MR) imaging of the liver has been useful in detecting hepatic tumors, especially hepatocellular carcinoma (HCC), and in characterizing the internal architecture of HCC. In this paper, we present MR image of the resected cases of HCC with the pathological findings, and assess MR image for the potential utility of demonstrating the pathologic features of HCC treated with TCE.

Carcinoma, Hepatocellular↗
PubMed1990

[Evaluation of intrahepatic distribution of inferior mesenteric blood flow by transrectally administered 123I-IMP].

Intrahepatic distribution of the inferior mesenteric blood flow was evaluated with scintigraphy with transrectally administered 123I-iodoamphetamine (IMP). Twelve patients without liver diseases were studied. The IMP image was divided into 3 types; bilateral, left lobar predominant and right lobar predominant. Bilateral, left lobar predominant and right lobar predominant types were observed in 5, 5 and 2 patients respectively. Furthermore, uneven distribution pattern in the left or right lobe was observed in 2 of 5 patients with bilateral lobar type, 4 of 5 patients with left lobar predominant type and 1 of 2 patients with right lobar predominant type. In one patient with left lobar predominant type, repeat examination demonstrated bilateral lobar type. These results suggest that intrahepatic distribution of the inferior mesenteric blood flow is not uniform and consistent.

Administration, Rectal↗