[Teaching machine for instruction of radiology (author's transl)].
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Audiovisual Aids↗
Biomedical subjects
J Nishikawa
Publications and source records attributed to J Nishikawa.
[Diagnosis of malignant lymphoma by lymphography; with special reference to differential diagnosis of diseases with similar findings].
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Adult↗
Computed tomography during arterial portography prior to transcatheter arterial therapy in hepatocellular carcinoma with marked portal extension: four case reports.
Computed tomography during arterial portography (CTAP) is acknowledge as a valuable preoperative method for the detection of small intrahepatic lesions in patients with liver neoplasm. Four patients with hepatocellular carcinoma (HCC) with marked portal extension are presented. Evaluation of intrahepatic portal blood flow was achieved more accurately by CTAP than by conventional arterial portography. CTAP also plays an important role in patients with inoperable HCC, since portal extension is the most important prognostic factor of transcatheter arterial therapy.
Adult↗
Calcification of peritoneal carcinomatosis from gastric carcinoma: a CT demonstration.
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Adenocarcinoma↗
Neural network mapping for nonlinear stereotactic normalization of brain MR images.
We present techniques of automatic nonlinear transformation of MR images (2D or 3D). A neural network automatically finds the corresponding parts between the subject's brain images and the standard images. By iterative operations, the network generates a set of image-shifting vectors to realize a plastic transformation. For precise matching, a set of markers can be placed manually before starting the transformation on landmarks of the images, e.g., on the anterior-posterior commissural line and on the central sulcus.
Brain Mapping↗
Deadtime of a single-crystal gamma camera in abdominal imaging.
The deadtime of a single-crystal gamma camera depends on the scattering condition, and differs among patients. The aim of this study was to estimate deadtime in posterior abdominal imaging. Radionuclide angiography of the posterior abdominal view was performed in 23 patients with a point source in the field-of-view, and temporal changes in count loss were assessed. The deadtime for each patient was calculated based on the count loss for the point source. The estimated deadtime ranged from 7.83-12.52 microsec, and was significantly correlated with the ratio of body weight in kg to body height in cm (y=13.143x+5.595, r=0.852, p<0.001). Count loss was successfully corrected using the deadtime predicted with the regression equation. In conclusion, the deadtime in posterior abdominal imaging can be predicted for each patient from the body weight and body height. The predicted deadtime may aid in improving the reliability of quantitative measurements by scintigraphic techniques.
Abdomen↗
Health care trends, Part I. The promise and perils of evidence-based medicine ... panel discussion.
Numerous studies have demonstrated that there are wide variations in the way physicians manage similar patients. This suggests that an evidence-based approach could lead to better outcomes with less cost. But practicing evidence-based medicine requires new skills, such as using computerized databases and applying the rules of evidence to primary and integrative studies in the medical literature. The progress of evidence-based medicine will depend in large measure on how quickly these new skills can be developed and integrated into the practice environment. Here's how six experts see the promise and the perils of evidence-based medicine, now and in the new millennium. Part 2 of the panel discussion will explore the new provider team, which includes nurses and, more recently, pharmacists, who are collaborating with physicians to provide disease management and drugs therapy management services.
Cooperative Behavior↗
Experience with photodynamic therapy (endoscopic laser therapy) for the treatment of early gastric cancer.
BACKGROUND/AIMS: Photodynamic therapy has been developed as an endoscopic laser therapy for gastrointestinal malignant tumors. The targets for curative upper gastrointestinal endoscopic therapy are carcinomas that are considered statistically unlikely to be accompanied with metastases to the lymph nodes. Endoscopic mucosal resection is the therapy of first choice for such carcinomas. In the application of photodynamic therapy, we narrow down its practical indications to patients who are not indicated for curative endoscopic treatment by preoperative examination or those with histologic findings of endoscopic mucosal resection specimens who reject surgical treatment or are at high risk in surgical treatment. METHODOLOGY: The effect of photodynamic therapy using Porfimer sodium and an Excimer dye laser was evaluated endoscopically in 8 lesions of 7 patients with early gastric cancer. RESULTS: Complete responses were obtained in all patients. As side effects, mild photosensitivity was seen in 6 patients and lasted for several months. CONCLUSIONS: Photodynamic therapy was safety employed, with success in 7 patients with early gastric cancer. We conclude that photodynamic therapy can be a useful palliative method with high tumor selectivity in the treatment of early gastric cancer.
Aged↗
Functional brain studies with H2(15)O-PET: strategies and problems for approaching higher brain functions with H2(15)O-PET.
Activation study using H2(15)O and PET is promising as a noninvasive approach to higher brain functions in humans. However before reaching a more complex paradigm, many fundamental problems need to be solved. In this study, we investigated the following issues: (1) reproducibility of regional cerebral blood flow in the resting state as measured by this method, (2) effect of physiological stimulation on cerebral blood flow, and (3) identification of activated areas on anatomical structures. Our data suggest that relative CBF images and their paired subtraction are more suitable for tapping functional localization. Changes in rCBF in the association cortex for more complicated tasks are, in general, smaller than those in the primary cortex. Combined display of PET images with three-dimensional reconstructed brain surface MR images was the most reliable technique for anatomical identification of the activated site.
Acoustic Stimulation↗
Effect of cervical spinal cord stimulation (cSCS) on cerebral glucose metabolism and blood flow in a vegetative patient assessed by positron emission tomography (PET) and single photon emission computed tomography (SPECT).
This paper presents, for the first time, assessments of cerebral glucose metabolism and cerebral blood flow before and after cervical spinal cord stimulation (cSCS) in a vegetative patient. Regional cerebral metabolic rates for glucose (rCMRglc) were measured with positron emission tomography and 18F-fluoro-2-deoxy-D-glucose. Regional cerebral blood flow (rCBF) was determined with single photon emission computed tomography and N-isopropyl p-123I-iodoamphetamine. Global CMRglc in the patient was less than one-third of that in normal control subjects. An increase in rCMRglc after one week of cSCS was observed in the cerebral cortex, predominantly on the right side, where the baseline level of rCMRglc before cSCS was more severely depressed. The pattern of increase in rCBF was almost the same as that in rCMRglc. The results suggest that cSCS activates glucose metabolism and that this is followed by an increase in cerebral blood flow.
Amphetamines↗
A new method for brain functional study using Tc-99m HMPAO SPECT.
The distribution of 99mTc-HMPAO in brain is in proportion to regional cerebral blood flow (rCBF) and can be interpreted as functional mapping. To evaluate local changes in CBF during neuropsychological testing, we developed a new subtraction method using HMPAO and SPECT. With patients resting, 15 mCi of HMPAO was injected and the first acquisition was performed, lasting a total of 10 minutes. Soon after the end of the first scan, patients were requested to undergo Buschke's memory test or to repeat words or numbers (repetition test). During the task, an additional 15 mCi of HMPAO was injected using the same position as in the first scan, and a second acquisition was started. A functional image was made by subtracting the image in the first scan from that in the second. In two patients with transient global amnesia and two normal controls, Buschke's memory test was performed in combination with SPECT. A Relative increase in activity was seen in the thalamus, subthalamic area, hippocampus, and some cortical areas, apparently reflecting local functional change induced by the memory task. In two patients with moderate Alzheimer's disease with severe memory loss, no increase was detected in these areas. In one patient with aphasia, the repetition test with SPECT was correlated with the WADA test and dichotic listening test, and good agreement was obtained. In conclusion, our new SPECT technique is useful in detecting alterations in rCBF during mental activity and can be applied to neurophysiological studies.
Alzheimer Disease↗
Early stage detection of chemotherapeutic effect on 203 GL glioma in mice as studied by P-31 NMR and flow cytometry.
The effect of chemotherapy against glioma in mouse was evaluated by 31P NMR spectroscopy and flow cytometry. We found that administration of ACNU or tegafur at a dose less than LD50 resulted in the partial suppression of the ratio of inorganic phosphate (Pi)/phosphocreatine (PCr) and phosphomonoester (PME)/creatine phosphate (PCr) after 24 or 48 hr, although these ratios are usually increased together with growth of tumors. Flow cytometric analysis of glioma in vivo showed an accumulation in cells containing tetraploid DNA by G2M block 24-48 hr after treatment. However, the change occurred at a period slightly later than that of the Pi/PCr ratio. In contrast, histological change was noted at eight days after administration. Hence, it is concluded that in vivo 31P NMR spectroscopy can detect a change in metabolic pathways in tumors as early as 24-48 hr after the administration of chemotherapeutic agents.
Animals↗
Computer simulation of ventricular wall motion using the finite element method.
To investigate how changes in the mechanical characteristics of the myocardium caused by cardiac diseases affect ventricular wall motion, a new computer program to simulate wall motion using the finite element method has been developed. A simple two-dimensional finite element model of the left ventricle is designed with an idealized tension-length curve applied to each element. Pathological changes in the ischemic process are induced in a certain portion of the model to make it possible to evaluate the relationship between the type and degree of changes and abnormal ventricular wall motion (i.e., hypokinesis, akinesis, and dyskinesis). Assumption of plastic deformation at the affected site of the model reproduced the genesis of a ventricular aneurysm. The model is then transformed into a three-dimensional wire frame structure, and the results can viewed from any perspective. These simulations enable the semiquantitative comprehension of cardiac wall motion without need for complicated physiological experiments and may be applied to human cardiac motion in combination with data obtained from cardiac scintigraphy, echocardiography, ventriculography, or cine-CT.
Computer Simulation↗
Clinical applications of Ga-67 DFO-DAS-fibrinogen.
Ga-67 DFO-DAS-fibrinogen scanning was performed in 15 patients to detect fresh arterial thrombus. Seven patients were preoperative cases of aortic aneurysm and eight were postoperative cases of graft bypass. Scanning was performed on the first and second days after the injection. Nine of 13 grafts in eight cases were visualized by 67Ga-DFO-DAS-fibrinogen scan. Velour Dacron grafts were more strongly visualized compared with woven Dacron or Goatex. In three patients with aortic aneurysm in whom fresh thrombus was identified by operative findings, arterial thrombus was clearly visualized by 67Ga-DFO-DAS-fibrinogen scan, whereas in three other patients with aortic aneurysm, thrombus was not visualized, although it was identified by other examinations. In one case, a marked accumulation was observed in the abdominal aorta, although no arterial thrombus was found at operation. This was thought to be an accumulation in a blood pool because it decreased on the second day. We think it important to observe the relative changes of accumulation.
Adult↗
N-isopropyl I-123 p-iodoamphetamine brain scans with single photon emission computed tomography: mental sweating and EEG abnormality.
We studied a patient with hyperhidrosis and electroencephalographic (EEG) abnormality using N-isopropyl I-123 p-iodoamphetamine (I-123 IMP) with single photon emission computed tomography (SPECT). EEG abnormality was found predominantly in the frontal area, and sharp wave bursts were induced by hyperventilation. Ictal and nonictal scans were obtained with simultaneous EEG recordings. Ictal scans revealed increased uptake of IMP in the frontal cortex, reflecting hyperperfusion to the frontal area. The ratio of IMP uptake of the frontal to the parietal cortex (F/P ratio) was calculated both in the ictal and nonictal phase. In the ictal phase, the F/P ratio was 1.23, compared with 0.91 in the nonictal phase. The data indicated altered regional cerebral blood flow with EEG abnormality and hyperventilation load. Although the relationship between sweating and cortical function is not fully understood, our study indicates that excessive mental sweating is related to frontal cortical dysfunction. I-123 IMP-SPECT seems valuable for topographical demonstration of epileptogenic lesions and understanding the pathophysiological process of mental sweating.
Adult↗
Localization of therapeutic gelatin emboli using radiolabeling--an experimental study.
Transcatheter embolization has recently gained widespread acceptance in the treatment of a variety of conditions. To clarify the localization of therapeutic gelatin particles, we have described a simple and safe technique of labeling gelatin particles with 99mTc using stannous chloride solution. This technique provides satisfactory labeling efficiency and allows excellent scintigraphic images of therapeutic gelatin emboli, thus making it possible to clarify the localization of the injected embolic material in vivo.
Animals↗
Bone scintigraphy in Maffucci syndrome.
Maffucci syndrome is a congenital, non-hereditary mesodermal dysplasia associated with multiple enchondromas and hemangiomas. The high risk of development of malignant tumors is well-known. A case of Maffucci syndrome in a 68-year-old man who suffered from multiple malignant degeneration and who was given a bone scintigraphic examination is reported with radiological and pathological findings. The scintigraphic findings are different for two histological different chondrosarcomatous lesions. It seems that uptake of Tc-99m MDP increases with the degree of calcification rather than whether the lesion is benign or malignant.
Aged↗
The value of the modified high temporal resolution phase analysis for the detection of myocardial infarction.
Recently, cardiac nuclear medicine, especially gated RI cardiac blood pool scan has been improved remarkably, and now phase analysis has been introduced. We have developed a new modified phase image, with the objective of improving the time resolution, by displaying a special range of phase angles (about pi/3 radian) with 16 color scales, which correspond to the ventricles. Compared with the conventional method, the high resolution phase image improved the sensitivity of diagnosis of the region of myocardial infarction. The sensitivity of the modified phase image was 91% (10 cases our of 11), whereas that of the conventional method was 27% (3 cases out of 11).
Adult↗