[Dynamic SPECT using Tc-99m hexamethylpropyleneamine oxime in patients with intracranial mass lesions--a comparison with Xe-133 and IMP].
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Biomedical subjects
Publications and source records attributed to S Jinnouchi.
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Dynamic studies of single photon emission computed tomography (SPECT) were performed with intravenous administration of N-isopropyl-p-[123I]iodoamphetamine ([123I]IMP) in 12 patients with meningiomas. Their vascularities were also assessed by angiography. Regions of interest (ROIs) were placed over the lesion and the contralateral presumed normal area, the symmetrical one if possible. Time-activity curves (TACs) were then constructed and the counting-rate ratio for the lesion to the contralateral presumed normal area (L/N ratio) was calculated in the first image of the dynamic SPECT. TACs were classified into three types: type I, an initial high uptake and rapid washout type, type II, an initial high uptake and slow washout one, and type III, an initial low uptake one. L/N ratios of angioblastic meningiomas were over 300%, while those of many fibroblastic ones were under 100%, at most 105%. We compared L/N ratios with angiographic vascularities and histologic types and conclude that dynamic SPECT with [123I]IMP is the examination of choice for evaluating the vascularity of lesions.
In a study of the distribution of N-isopropyl-p-131I-iodoamphetamine (IMP) in the permanently ischemic brain of 35 mongolian gerbils, the right common carotid artery was ligated under ether anesthesia. After given time intervals, 1.35 MBq (50 microCi) of IMP was injected into 17 gerbils which had severe neurological symptoms, and into 3 normal gerbils for controls. One minute there after each gerbil was sacrificed and brain autoradiography was performed. The activity of IMP in various parts of the brain was calculated from each autoradiogram. Low perfusion areas were observed in the right cerebral hemisphere and the brain stem (5-25% of normal value) from the first minute up to 24 h after ligation. In addition, low perfusion areas were also observed in the left cerebral hemisphere (40-60% of normal value) which represented a remote effect. These results suggest the usefulness of IMP for demonstrating cerebral ischemia and diaschisis.
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We studied the distribution of N-isopropyl-p-[131I]-iodoamphetamine (IMP) in the ischemic brain of 44 mongolian gerbils. The right common carotid artery was temporarily occluded by a clip and recirculated 3 h later. After given time intervals, 50 microCi of IMP was injected into 18 gerbils which had symptoms. One min after injection (or 10 min, 1 h, or 6 h after injection in other gerbils), each gerbil was killed and autoradiography was performed. IMP activity in various parts of the brain was calculated as %Dose/g from each autoradiogram. At one min after recirculation, partial no flow phenomenon was observed in the right cerebral hemisphere. From 10 min to 24 h after recirculation, a high uptake region was observed partially in the right cerebral hemisphere and thalamus. The high activity disappeared rapidly 10 min after injection. It seemed that this high uptake indicated luxury perfusion at the location of severe tissue damage. In the left side, the low perfusion recovered to an almost normal value at one to three days after recirculation. These results suggested the possibility that IMP could demonstrate luxury perfusion and diaschisis.
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The discrepancy between three methods for cerebral perfusion imagings in the case of a man with meningioma is presented. Imaging with N-isopropyl-P-[I-123] iodoamphetamine (IMP) showed no activity in the tumor. Imaging with Tc-99m hexamethylpropyleneamine oxime (HM-PAO) and the local cerebral blood flow (LCBF) image with Xe-133 inhalation showed high tumor activity. IMP is a more accurate method for imaging the brain tissue blood flow.
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Serum neuron-specific enolase (NSE) levels were studied in 105 patients with malignant neoplasms (lung cancer 38, others 67), 13 patients with various benign diseases and 7 healthy adults. The mean serum NSE level in adult control subjects was 7.4 +/- 0.8 ng/ml, and cut off level was decided 10 ng/ml. Serum NSE levels were elevated in 14/38 (37%) of patients with lung cancer and in 14/67 (21%) of patients with the other malignant neoplasms. In patients with benign diseases, serum NSE level was elevated only in one patient with pituitary adenoma. In 7 patients with small cell lung cancer, the positive rate was higher (86%) than in those with non-small cell lung cancer (26%), and serum NSE levels were higher than 25 ng/ml except one case. There was no correlation between serum NSE and CEA (carcinoembryonic antigen) levels in patients with small cell lung cancer, also in patients with lung cancer. The measurement of serum NSE level seemed to be useful for diagnosis in patients with small cell lung cancer.
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The biodistribution of N-isopropyl-p-iodoamphetamine (IMP) was studied in the rat brain. 131I-labelled IMP was injected intravenously in awake animals. Activities in the brain of Sprague-Dawley rats were 2.68-3.22 (% dose/g) in the cortex and 0.59-0.66 (% dose/g) in the white matter at 1 min p.i. Activities in the cortex were slightly increased at 60 min p.i., while activities in the white matter increased markedly at 60 min and 6 h p.i. Therefore, the cerebral cortex-to-white matter ratio decreased from 5 to 1 within 60 min after injection. Autoradiograms of the rat brain at 1-10 min p.i. showed high contrasts. Activities were high in the cortex and low in the white matter, but homogeneous at 60 min-6 h. IMP seems to be a useful agent for cerebral perfusion imaging in the early phase after injection. Knowledge of biodistribution of this agent is considered to be indispensable for the interpretation of images.
To evaluate the most appropriate CT angles for the skull base, four adult phantom skulls of various shapes were examined by CT. 15 osseous sites in each skull base were selected and the optimum angle for their delineation was determined. Using Reid's base line (0 degree), many sites could be imaged best at angles up to +20 degrees, and +10 degrees was found to be optimum. Examinations of patients using OM-line as a reference disclosed imaging rates in excess of 70% for sites other than the hypoglossal canal, the optic canal and foramen rotundum, which are in horizontal planes.
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In the scintigraphic diagnosis of diffuse hepatocellular diseases, increased splenic uptake of colloids and splenomegaly are helpful signs. To quantify these patterns, the volume and activity of liver and spleen were measured by using single photon emission computed tomography (SPECT). The spleen-to-liver (S/L) ratios in volume and activity that were calculated from SPECT images were estimated in normal individuals and in patients with diffuse hepatocellular diseases. The maximum normal limits of S/L ratios of volume, activity, and activity/volume were predicted as 0.19, 0.087, and 0.72 (mean +/- 2 s.d.). Twenty-two of twenty-three patients (96%) with liver cirrhosis had at least two elevated S/L ratios, and three elevated S/L ratios could clearly differentiate the patient with liver cirrhosis from normal individuals. On the other hand, only six patients (32%) with chronic hepatitis had elevation of any S/L ratio. Abnormal S/L ratios of activity/volume in the range from 0.72 to 1.05 were not obvious on planar or SPECT images.