Biomedical subjects

N Tonami

Publications and source records attributed to N Tonami.

At least 181 records · Page 10Linked to original sources

PubMed1993

[Diagnosis of tumor with thallium-201].

201Tl accumulates well in the malignant tumors. Since high uptake ratio of tumor to blood can be obtained soon after injection, a small lesion can be detected by SPECT imaging. It has been observed that 201Tl imaging is useful to detect recurrent lesions or metastatic lesions from thyroid cancer, lung cancer, brain tumor, breast cancer, mediastinal tumor, bone and soft tissue tumor, pancreas cancer and colon cancer. The clinical application of 201Tl is expected to expand. Although 201Tl accumulates in benign lesions, the accumulation in malignant lesions retained more longer than in benign lesions. This unique characteristic is useful to separate benign from malignant lesions. 201Tl is expected useful for evaluating response of tumor to radiation therapy and/or chemotherapy as 201Tl accumulates in viable tumor cells.

Brain Neoplasms↗

PubMed1993

[Quantitative analysis of brain perfusion using radionuclide angiography with 99mTc-HMPAO].

A noninvasive simple method for quantitative radionuclide angiography with 99mTc-dl-hexamethyl propylene amine oxime (99mTc-HMPAO). The method of graphical analysis was employed for the evaluation of the unidirectional influx constant (Ku) from the blood to the brain for the tracer. The Ku values were standardized to represent objective and comparable values, brain perfusion indices (BPI), among studied subjects by setting the ratio of ROIbrain size to ROIaorta size to 10. The mean +/- SD of the whole-brain BPI values for the 41 normal controls was 11.15 +/- 2.61, and biphasic reduction with advancing age was observed. The mean of the whole-brain BPI of 7.95 with SD of 2.35 in 103 patients with cerebrovascular disorders was significantly lower than that in normal controls. The right to left ratio of BPI showed wider dynamic range than that of the total counts of SPECT. This technique is quite easy to apply as an adjunct to SPECT and may be helpful in the quantitative evaluation of brain perfusion in routine clinical studies.

Adult↗

PubMed1993

[Evaluation of renal function using 99mTc-MAG3: comparison with 123I-OIH and 99mTc-DTPA].

The utility of 99mTc-mercaptoacetyltriglycine (MAG3) with studied clinically. In the renography obtained with 99mTc-MAG3, the abdominal aorta and the common iliac arteries were clearly visualized in the vascular phase. Due to less background activity and high target to background ratio, the quality of 99mTc-MAG3 image was superior to that of 123I-OIH or 99mTc-DTPA image. The parameters on the renogram including Tmax, T2/3, and T1/2 were compared. The correlation of Tmax and T2/3 or T1/2 were not significant between 99mTc-MAG3 and 123I-OIH. Another parameter of C20/Cmax, where C20 and Cmax are renal activities at 20 min after injection and at Tmax respectively, showed an excellent correlation between 99mTc-MAG3 and 123I-OIH. Using C20/Cmax, pattern of renogram can be characterized numerically. Concerning about the relation between C20/Cmax and renogram pattern, standard renogram pattern showed the C20/Cmax value of less than 0.4, while hypofunctioning pattern showed more than 0.5. The correlation coefficient between the renal uptake of 99mTc-MAG3 and 123I-OIH was 0.880 with a correlation plot: "Y = 1.16X-0.043", where X and Y represent renal uptake of 99mTc-MAG3 and 123I-OIH, respectively. It can be concluded that 99mTc-MAG3 is useful renal imaging agent as an alternative to 123I-OIH, in order to evaluate the proximal tubular function and calculate ERPF.

Adult↗

PubMed1993

[Assessment of congenital heart disease by a thallium-201 SPECT study in children: accuracy of estimated right to left ventricular pressure ratio].

The characteristics of correlation between the right-to-left ventricular systolic pressure ratios (RVp/LVp) and the thallium-201 right-to-left ventricular (201Tl R/L) count ratios was investigated in children with various congenital heart diseases. High-resolution three-headed SPECT system equipped with either parallel-hole or fan-beam collimators was used. In a total of 102 patients, the correlation between RVp/LVp and 201Tl R/L average count ratios was good in both planar (r = 0.89, p = 0.0001) and SPECT studies (r = 0.80, p = 0.0001). Quantitative analysis of myocardial uptake by SPECT demonstrated the characteristic pattern of each disease as well as the differences in the right ventricular overload types. When the linear regression analysis was performed in each heart disease, ventricular septal defect showed most excellent correlation. Complex heart anomalies also showed positive correlation (r = 0.51, p = 0.05) with RVp/LVp, and it can be used to estimate right ventricular pressure. After surgical treatment of tetralogy of Fallot and pulmonary stenosis, the decrease of 201Tl R/L count ratio was in accordance with improvement of right ventricular overload. We conclude that 201Tl SPECT study can be a good indicator for estimation of right ventricular pressure.

Adolescent↗

PubMed1992

[Evaluation of the internal mammary nodes by lymphoscintigraphy and ultrasonography in patients with breast cancer].

The efficacy of lymphoscintigraphy and ultrasonography was evaluated in the detection of internal mammary lymph node (IMN) metastases in patients with breast cancer. On histological examination of IMN, 10 patients had metastases (positive group) and 47 did not (negative group). On lymphoscintigraphy, lack of uptake in the parasternal region of the affected side was classified as abnormal. The frequency of this abnormal finding was not significantly different between both groups. On sonography, the thickness of the sonolucent internal mammary area was measured. The thickness of the affected side was 6 mm or more in two patients of the positive group and only one of the negative group. A thickness of over 6 mm on the affected side was statistically significant (p less than 0.05). The difference in thickness between the affected side and the healthy side was 3 mm or more in four patients of the positive group, and was less than 3 mm in all patients of the negative group. A difference in thickness of more than 3 mm between the two sides was extremely significant (p less than 0.001). In conclusion, sonography is valuable in detecting IMN metastases, while lymphoscintigraphy is not useful. Sonography is recommended as an efficient diagnostic modality for IMN metastases.

Adult↗

PubMed1992

A quantitative approach to technetium-99m hexamethylpropylene amine oxime.

A non-invasive, simple method for the quantitative evaluation of brain perfusion is presented using intravenous radionuclide angiography with technetium-99m hexamethylpropylene amine oxime (99mTc-HM-PAO). Graphical analysis was employed for the evaluation of the unidirectional influx constant (ku) of the tracer from the blood to the brain. The ku values were standardized to provide objective and comparable values, brain perfusion indices (BPI), among studied subjects by setting the ratio of ROIbrain size to ROIaorta size at 10. The whole-brain BPI values for the normal control subjects showed a significant negative correlation with advancing age (r = -0.632, P = 0.0204, n = 13). The mean of the whole-brain BPI of 7.0 (SD = 1.4) in 20 patients with cerebrovascular disorders was significantly lower than that of 10.6 (SD = 1.5) in 13 normal control subjects. The BPI measurements showed only minimal intra- and interobserver variability. Changes of the ratio of ROIaorta size and ROIbrain size did not significantly influence the BPI values. Hemispherical BPI values in 19 subjects (n = 38) showed highly significant correlations with the hemispherical mean cerebral blood flow values obtained from Xenon-133 single photon emission tomography (SPET) (r = 0.926, P = 0.0001 for the early picture method and r = 0.932, P = 0.0001 for the sequential picture method). This technique is easy to apply as an adjunct to SPET and may be helpful in the quantitative evaluation of brain perfusion in routine clinical studies.

Adult↗

PubMed1992

Asymmetric abnormality of renal perfusion with symmetric function in aortic dissection.

Two cases of aortic dissection are presented in which discordance between renal perfusion and function has been demonstrated with Tc-99m DTPA. Renal perfusion on the affected side was decreased on blood flow imaging, whereas renal function, including parenchymal accumulation and excretion assessed by subsequent sequential imaging, were similar for both kidneys. These results suggest that blood flow imaging more readily demonstrates a unilateral renal abnormality in patients with aortic dissection.

Aortic Dissection↗

PubMed1992

Acetazolamide effect on vascular response in areas with diaschisis as measured by Tc-99m HMPAO brain SPECT.

The effects of acetazolamide (Diamox) on vascular response were investigated in areas with intrahemispheric thalamic diaschisis and crossed cerebellar diaschisis using consecutive Tc-99m HMPAO brain SPECT studies before and after Diamox administration. All six patients with thalamic diaschisis and five of eight patients with crossed cerebellar diaschisis at baseline showed significantly augmented perfusion after Diamox administration in the affected thalamus and cerebellum compared with that in the contralateral unaffected areas. These results suggest more dilatation of the arterioles in areas with diaschisis after Diamox administration than in areas without diaschisis. Diamox may produce relative luxury perfusion in areas with diaschisis.

Acetazolamide↗

PubMed1992

Discordant hepatic uptake of Tc-99m NGA and Tc-99m PMT in a patient with hepatoma.

The authors report discordant hepatic uptake of Tc-99m NGA and Tc-99m PMT in a patient with hepatoma. Tc-99m PMT uptake was delayed and Tc-99m NGA concentrated in another area, thereby demonstrating that the uptake mechanisms for Tc-99m NGA and Tc-99m PMT are different. Tc-99m NGA imaging may be useful in characterizing the focal hepatic lesion of Tc-99m IDA or Tc-99m PMT concentration.

Albumins↗

PubMed1992

Tc-99m HMPAO-labeled leukocytes for hematopoietic marrow imaging. Comparison with In-111 chloride.

The current study was initiated to define whether Tc-99m leukocyte imaging, compared to In-111 chloride imaging, could provide additional information on the hematopoietic activity of the bone marrow in diffuse hematologic disorders. A total of 11 patients with hematologic disorders were studied both with Tc-99m leukocytes and In-111 chloride. One patient with myelofibrosis showed disparate tracer distribution in the bone marrow between the two; Tc-99m leukocyte uptake in the central marrow was highly decreased, whereas In-111 chloride showed expanded marrow. The disparate results of granuloid hypoplasia and erythroid hyperplasia obtained by bone marrow biopsy and aspiration in this patient were thought to give an explanation for the radionuclide findings. The remaining 10 patients showed similar tracer distribution in the marrow, and the observation of hematopoietic cellularity confirmed by bone marrow biopsy and aspiration correlated well with the radionuclide findings. These results demonstrate that Tc-99m leukocytes may be a potential imaging agent for evaluating hematopoietic activity in the bone marrow, in particular granulopoietic activity.

Adult↗

PubMed1992

An autonomously functioning thyroid carcinoma associated with euthyroid Graves' disease.

A 39-yr-old man with an autonomously functioning thyroid carcinoma is presented. Only 17 similar cases have been reported in the literature. The patient had unilateral Graves' ophthalmopathy. He was euthyroid as reflected by normal TSH concentration, whereas the results of a T3 suppression test established the presence of autonomous thyroid function. A thyroid scan with (123)I revealed a hot nodule corresponding to the location of a papillary carcinoma and remained substantially unchanged after T3 administration. The hyperfunction of the carcinoma itself was clearly confirmed by the intense concentration of (131)I within the tumor on microautoradiograms. While a hot nodule on radioiodine scan is unlikely to be malignant, the possibility of carcinoma should not be overlooked.

Adult↗

PubMed1992

[The utility of quantitative 99mTc-GSA liver scintigraphy in the evaluation of hepatic functional reserve: comparison with 99mTc-PMT and 99mTc-Sn colloid].

Using data from 17 patients with liver cirrhosis and 3 patients with fatty liver, we have compared the utility of 3 hepatic imaging agents in the evaluation of hepatic functional reserve. Evaluated here were 99mTc-galactosyl human serum albumin (GSA) which is a new ligand for hepatic binding protein, 99mTc-N-pyridoxyl-5-methyl tryptophan (PMT) of a hepatobiliary agent, and 99mTc-Sn colloid. In each patient, we performed these 3 imaging studies within a week and also examined hepatic function tests (indocyanine green test, hepaplastin test, choline-esterase, etc). In each imaging study, serial images and dynamic data were obtained after the injection of 99mTc-GSA (185 MBq/3 mg), 99mTc-PMT (185 MBq), or 99mTc-Sn colloid (185 MBq). Using the obtained dynamic data, we analyzed the liver kinetics of the 3 agents based on 1 compartment model with 3 parameters (hepatic clearance, hepatic excretion rate, non-specific volume of distribution). From fitting the liver and heart data to this model, three unknown parameters were determined. Patlak plot was also applied in order to estimate liver uptake rate. Both curve fitting and Patlak plot could determine appropriate parameters in every study. In 99mTc-GSA, a nonlinear 3 compartment model was also applied in order to estimate hepatic blood flow, liver receptor density, and affinity of receptor-GSA binding separately. Using the obtained parameters, we analyzed the correlations between the parameters and the results of hepatic function tests. In all of the parameters, those obtained from 99mTc-GSA imaging showed the most significant statistical correlation with the results of hepatic function tests. From the present results, 99mTc-GSA imaging was concluded to be the best for evaluation of hepatic functional reserve.

Adult↗

PubMed1992

[Characteristics of the myocardial SPECT images of 99mTc-MIBI and 99mTc-teboroxime].

Characteristics of the myocardial distribution of 99mTc-MIBI and 99mTc-Teboroxime was compared with the myocardial distribution of 201Tl. We made summed myocardial images, in which central three short-axis SPECT slices were added. Rectangular region of interest (ROI) was set on each myocardial segment, and mean counts of each myocardial region was obtained using summed short-axis images. The ratio of inferior-to-anterior mean counts (I/A) was 0.69 +/- 0.20 in 99mTc-MIBI and 0.62 +/- 0.16 in 201Tl. The ratio of inferior-to-lateral mean counts was 0.70 +/- 0.18 and 0.65 +/- 0.13, respectively. Both ratios in 99mTc-MIBI were significantly higher than those in 201Tl (p less than 0.05). 201Tl to 99mTc-MIBI ratios of these two values were 1.11 +/- 0.17 (I/A) and 1.08 +/- 0.16 (I/L). The ratios of I/A and I/L of 99mTc-MIBI were about 10 percent higher than those of 201Tl. 99mTc-Teboroxime dynamic short-axis SPECT images of every three-minute were obtained. The ratios of counts in each wall were calculated similarly. After about 8 minutes, gradual increase in hepatic activity can be a cause of quantitative error in the assessment of SPECT images. We obtained the data with a human cardiac phantom. The myocardial phantom filled with 99mTc or 201Tl was placed in the mediastinal portion that is surrounded by the lung (saw dust) and vertebra (plastic bar). The ratio of I/A was 0.79 and I/L was 0.85 in 201Tl. The I/A ratio was 0.93 and I/L was 0.97 in 99mTc. Both ratios in 99mTc were about 15 percent higher than those in 201Tl.(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Circulation↗

PubMed1992

Application of a continuous ventricular function monitor with miniature cadmium telluride detector to patients with coronary artery bypass grafting.

A continuous ventricular function monitor with a miniature cadmium telluride detector was evaluated and applied to patients with coronary bypass surgery (CABG). Ejection fraction (EF) at rest and change in EF from rest to exercise and postexercise (Y) measured with the device correlated with that of the gamma camera (X) (Y = 0.86x + 6.8(%), r = 0.87, n = 110, p less than 0.001, and Y = 0.96x + 0.4(%), r = 0.90, n = 37, p less than 0.001 respectively). Left ventricular function during and after supine ergometer exercise was monitored in 54 patients before and after CABG. The EF change from baseline to peak exercise improved from -5.9% +/- 8.9% before CABG to 7.2% +/- 7.9% after CABG (p less than 0.001). In all patients but two, a rapid EF increase just after exercise over baseline EF was observed. This EF "overshoot" during recovery increased from 11.5% +/- 6.5% to 16.4% +/- 6.0% (p less than 0.001) after CABG. The time from the cessation of exercise to EF overshoot decreased from 153 +/- 80 sec to 76 +/- 49 sec (p less than 0.001) after CABG. The continuous ventricular function monitor with a miniature cadmium telluride detector is able to measure EF reliably. Following successful aortocoronary bypass, EF response during exercise improved and the EF overshoot in the recovery phase became faster and higher.

Cadmium↗

PubMed1991

The role of Tc-99m IDA hepatobiliary and Tc-99m colloid hepatic imaging in primary biliary cirrhosis.

To assess the presence of primary biliary cirrhosis, 15 patients at various histopathologic stages were studied by Tc-99m IDA hepatobiliary and/or Tc-99m colloid hepatic imaging. In the earlier stages (I and II), seven of eight patients (88%) showed uniform hepatic retention of Tc-99m IDA. Of seven patients in the same stage, however, four (57%) showed no abnormality on Tc-99m colliod imaging. In three of these four negative patients (75%), uniform hepatic retention of Tc-99m IDA was noted. In the later stages (III and IV), all seven patients showed decreased clearance with or without delayed tracer appearance in the intestine and prominent hepatic retention on Tc-99m IDA imaging; with Tc-99m colloid imaging there was enlargement of the spleen and increased activity in the spleen and bone marrow. Thus, Tc-99m IDA imaging is considered to be more useful in revealing this functional disorder at the earlier stage of primary biliary cirrhosis and in evaluating progression from an earlier to a later stage of disease. Tc-99m colloid imaging also effectively evaluated progression.

Bone Marrow↗

PubMed1991

Papillary carcinoma in ectopic thyroid detected by TJ-201 scintigraphy.

A 37-year-old man with papillary carcinoma in an ectopic thyroid is presented. Excisional biopsy revealed the cervical mass to be a metastasis from thyroid cancer. X-ray, ultrasonography, and computed tomography, however, failed to identify the primary tumor in the thyroid. Incidental TI-201 uptake was noted in the midline of the anterior neck, and a palpable nodule was discovered in this area. Fine needle aspiration cytology demonstrated Class V papillary adenocarcinoma, and subsequent surgery confirmed a papillary carcinoma in the ectopic thyroid. This case suggests the usefulness of TI-201 scintigraphy for the detection of ectopic thyroid malignancy.

Adenocarcinoma, Papillary↗

PubMed1991

Tc-99m HMPAO SPECT analysis of neuroleptic effects on regional brain function.

This report describes a new approach to the evaluation of neuroleptic effects on regional brain function. Using Tc-99m HMPAO SPECT imaging, consecutive brain perfusion studies before and after acute haloperidol administration were performed on three schizophrenic patients and two normal volunteers. The antipsychotic drug ameliorated the hypoactivity in the frontal lobe and suppressed the hyperactivity in the temporo-occipito-parietal lobe selectively in the dominant hemisphere in the schizophrenic patients. It did not exert a significant influence on the brain perfusion pattern in normal volunteers. This nuclear medicine technique seems to be useful for the evaluation of drug effects in psychiatric diseases.

Adult↗

PubMed1991

201Tl SPECT in the detection of mediastinal lymph node metastases from lung cancer.

201Tl SPECT was performed to detect mediastinal involvement in 80 patients with lung cancer who underwent surgery within a week after the SPECT study. Out of 29 patients with mediastinal involvement 16 (55%) were positive on the 201Tl early scan at 15 min postinjection and 22 (76%) were positive on the delayed scan at 3 h. These metastatic lymph nodes tended to be visualized much better on the delayed scan. In all patients with true positive results on the delayed scan, the mediastinal lymph nodes were plural, with a lesion of more than 14 mm in size. Seven false negative cases were found to have metastatic lesions less than 12 mm in size. Both the early and delayed scans showed false positive accumulation in six of 51 patients without mediastinal involvement (specificity 88%). Thus the overall accuracy for the delayed scan was 84%. The 201Tl delayed SPECT is thought to be a good noninvasive method for assessing mediastinal lymph node metastases from lung cancer.

Aged↗