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M Furudate

Publications and source records attributed to M Furudate.

At least 37 records · Page 2Linked to original sources
PubMed1993

Radionuclide constant pressure perfusion study on measurement of exit urine flow: experimental and preliminary clinical investigations.

To calculate exit urine flow from the renal pelvis to the bladder in hydronephrosis, a simple method, radionuclide constant pressure perfusion study, was used. The mathematical model proposed for calculation of the exit flow (F) was simple: F = (initial slope)/Do'/exp(-0.148d), where F is expressed as flow rate (ml. per minute) of infused radioactive solution into the bladder. The value of the initial slope is expressed as a count rate per minute of time-activity curve of the bladder. Do' is a count rate per ml. of infused radioactive solution, which was measured by a gamma camera in air, and d is depth (cm.) of the bladder from the body surface to the vesical mucosa. The number -0.148 indicates the effective linear attenuation coefficient of 99mtechnetium, which was determined by a phantom study. In the experimental studies calculated flow correlated well with real pump flow. In preliminary clinical studies in 16 patients (20 kidneys) who underwent nephrostomy, measurement of flow rate at steady intrapelvic pressure with no subtraction of intra-abdominal pressure in 12 of 14 nonobstructed cases demonstrated a pressure-dependent pattern in which flow increased linearly in response to the pressure increase. In 2 nonobstructed children radionuclide constant pressure perfusion study failed: 1 due to crying and 1 to unknown causes. In 2 cases of complete or equivocal obstruction by constant perfusion (Whitaker test) only minimal or no flow rate was found at the maximum intrapelvic pressure increase of 24 cm. water. The urine flow was observed only in the repeated study in 3 patients. These phenomena were assumed to be due to immature expertise in the new technique. This new technique can provide physiological measurement of the urine flow at variable levels of constant intrapelvic pressure in hydronephrotic patients, although the pressure-flow relationship for identifying partial obstruction from nonobstruction still remains to be clarified in further clinical studies.

Adolescent↗
PubMed1993

Phase II study of Tc-99m MAG3 in patients with nephrourologic diseases.

Tc-99m-labeled mercaptoacetyltriglycine (Tc-99m MAG3) is a recently introduced radioagent that is excreted by tubular function. The aim of this study was to test Tc-99m MAG3 as an imaging agent for renal scintigraphy and renal plasma flow measurement. Image quality was tested with four different administered doses of Tc-99m MAG3, 100 MBq, 200 MBq, 300 MBq and 400 MBq, in four patients each. All administered doses except 100 MBq were sufficient for visible inspection of the nephrogram and drainage images; however, an administered dose higher than 300 MBq was necessary to maintain the quality of the blood perfusion image. The blood clearance with Tc-99m MAG3 or I-131 orthoiodohippurate (I-131 OIH) was calculated within the same day by the single blood sampling method. The blood clearance with Tc-99m MAG3 was 1.2-fold lower than with I-131 OIH, but correlated well (OIH = 91.34 +/- 0.932 MAG3, r = 0.953, P < 0.001). The blood clearance with Tc-99m MAG3 also correlated with the percentage of renal uptake estimated by the count-based gamma camera method at 1.5 to 2.5 minutes after injection (ERPF = -59.13% +/- 16.87% uptake, r = 0.845, P < 0.01). The mean labeling yield of Tc-99m MAG3 was 97%. None of the patients complained of side effects from Tc-99m MAG3. Tc-99m MAG3 is concluded to have good properties as a tubular radioagent for dynamic renal scintigraphy and renal plasma flow measurement.

Female↗
PubMed1993

Captopril renoscintigraphy with Tc-99m DTPA in patients with suspected renovascular hypertension. Prospective and retrospective evaluation.

Sensitivity and specificity of captopril renoscintigraphy (CRS) with Tc-99m DTPA has been analyzed in 41 cases, 16 with renovascular hypertension (RVH) and 25 with non-RVH. The sensitivity and specificity of the baseline study were 63% (10/16) and 63% (12/19), respectively, based on the split renal function study in which the lower limit of normal was assumed to be 42% of the total renal uptake. Captopril renoscintigraphy yielded 67% (12/18) sensitivity and 76% (19/25) specificity. The low specificity of CRS was due to the application of a prospective criterion of the captopril-induced reduction rate (CRR) of less than -20%, which was calculated from the renal uptake before and after captopril. When criteria of CRR less than -25% were used, the specificity of CRS was improved to 96%, but the sensitivity declined to 61%. Changes in the configuration of the renogram induced by captopril also had high specificity but low sensitivity. Renovascular hypertension was most likely when criteria for both CRR and the renogram were fulfilled. These criteria often were diagnostic in patients with bilateral renal artery stenosis that showed variable scintigraphic responses to captopril challenge. Captopril renoscintigraphy is a very specific means to evaluate RVH, but may have limitations in certain clinical situations such as poorly preserved function of the affected kidney, prior long-term administration of captopril, prior surgical manipulation of stenotic renal artery, and chronic renal parenchymal damage.

Adult↗
PubMed1993

Comparative study of renal scintigraphy with 99Tcm-mercaptoacetyltriglycine and 123I-orthoiodohippurate.

This study was undertaken to compare image quality, renal handling and plasma clearance of 99Tcm-mercaptoacetyltriglycine (99Tcm-MAG3) with those of 123I-orthoiodohippurate (123I-OIH). 99Tcm-MAG3 was prepared in-house using an instant kit vial and 123I-OIH was commercially available in a form already labelled. Both studies were undertaken in 20 patients with nephrourological disorders after intravenous (i.v.) injection of 300 MBq 99Tcm-MAG3 and 34 MBq 125I-OIH within the time interval of 3 to 4 days. 99Tcm-MAG3 was much superior to 123I-OIH in visualization of renal perfusion, renal parenchyma and urinary tract. The time parameters of the renogram, Tmax and T1/2 were significantly prolonged in 99Tcm-MAG3 compared to those for 123I-OIH (P < 0.05). Plasma clearance of 99Tcm-MAG3 was also slower than that of 123I-OIH but correlated well with that of 123I-OIH (r = 0.958, P < 0.01). The % renal uptake of 99Tcm-MAG3 per injected dose, which was calculated by the gamma camera method, also correlated well with effective renal plasma flow (ERPF) calculated by the single blood sampling method (r = 0.940, P < 0.01). The renal handling and plasma clearance of 99Tcm-MAG3 are not completely identical with those of 123I-OIH. However, 99Tcm-MAG3 has the clinical advantages of superior image quality, the feasibility of gamma camera measurement of quantitative renal uptake, and ready availability for routine clinical use.

Adult↗
PubMed1993

Technetium-99m-labeled recombinant tissue plasminogen activator for the imaging of emboli in vivo.

Tissue-type plasminogen activator (t-PA) effectively lyses active thrombus by direct action. Recombinant t-PA (rt-PA) was labeled with technetium-99m (99mTc) to investigate the in vivo binding to fibrin clots in a feline cerebral embolism model created by insertion of an artificial fibrin clot within the carotid artery. 99mTc-rt-PA administered intravenously provided clearer imaging of clots after priming with cold rt-PA, with uptake peaking 5-10 minutes after the injection. 99mTc-labeled human serum albumin was not retained at clot sites. Systemically administered 99mTc-rt-PA binds to fibrin clots within carotid arteries in our feline model. Our results suggest that the interaction of intrinsic plasminogen activator inhibitors with extrinsically administered rt-PA may regulate the demonstration of a clot, although the precise mechanism is unclear.

Animals↗
PubMed1993

[Role of 99mTc-labeled RBC SPECT in the diagnosis of hepatic hemangioma--comparison with US, CT and angiography].

The roles of planar imaging and SPECT with 99mTc-labeled RBC, US, Dynamic CT and angiography in the diagnosis of hepatic hemangioma were evaluated. The study group consisted of 18 patients with a total of 40 hemangiomas and 13 patients with a total of 21 non-hemangiomas. Among these patients, 5 patients with a total of 8 hemangiomas and 10 patients with a total of 14 non-hemangiomas were diagnosed by operation and biopsy. In all 40 hemangiomas, sensitivity for planar imaging was 35%, SPECT 50%, US 53%, Dynamic CT 82% and angiography 81%, respectively. When the tumor size was greater than 2.2 cm by SPECT and 2.8 cm by planar imaging, their sensitivity for both methods was 100%. Specificity for planar imaging was 100%, SPECT 95%, US 81%, Dynamic CT 100% and angiography 83%, respectively. One patient with hepatocellular carcinoma diagnosed by angiography showed increased uptake on SPECT. Because of the highest accuracy for SPECT in hemangioma greater than 2.0 cm, SPECT should be considered to be the method of choice for noninvasive diagnosis of hemangioma.

Adult↗
PubMed1992

Parthenogenetic development of bovine oocytes treated with ethanol and cytochalasin B after in vitro maturation.

The present study was conducted to investigate the effects of different culture durations (24-36 hr) on bovine oocyte maturation in vitro and the effect of the presence or absence of cumulus cells at the time of treatment to induce parthenogenetic activation (exposure to ethanol and cytochalasin B; CB) (experiment I). The effects of dosage (2.5 or 5.0 micrograms/ml) and incubation time (2.5, 5, or 10 hr) in CB (experiment II) on the subsequent development to the blastocyst stage in vitro was also investigated. In experiment I, cleavage and development to the blastocyst stage were not affected by the presence or absence of cumulus cells at the time of parthenogenetic activation. However, the 24-hr culture duration for in vitro maturation had a significantly lower rate of development to the blastocyst stage than the longer culture durations (27-36 hr). In experiment II, treatment with 5 micrograms/ml CB for 5 hr showed the highest percentage of development to blastocyst in the oocytes matured for both 27 and 30 hr. To determine the viability of the parthenogenetic embryos (morulae and blastocysts), four recipient heifers received two embryos each, and one heifer was found to be pregnant on day 35 following transfer. Although fetal heartbeat was not observed, the subsequent estrus was prolonged in all heifers. The present results demonstrate development of in vitro-matured, parthenogenetically activated bovine embryos up to the preimplantation stage.

Animals↗
PubMed1992

Single photon emission computed tomography using 201Tl chloride in pulmonary nodules: comparison with 67Ga citrate and 99mTc-labeled hexamethylpropyleneamine-oxime.

A single photon emission computed tomography (SPECT) with 201Tl chloride (Tl-201) was carried out prospectively in 50 patients with pulmonary nodules and its diagnostic value was compared with those of 67Ga citrate (Ga-67) and 99mTc-labeled hexamethylpropyleneamine-oxime (Tc-99m-HMPAO). Tl-201 SPECT provided 88% (early)-91% (delayed) sensitivity, 85% (early and delayed) specificity and 87% (early)-89% (delayed) accuracy. The sensitivity of the Tl-201 planar image was 56 (early)-62% (delayed), which was significantly lower than that of SPECT. Delayed SPECT images at 2 hour postinjection were more preferable to disclose the malignant pulmonary nodule than early SPECT images at 15 minutes postinjection. The application of SPECT with Ga-67 failed to improve the sensitivity of planar imaging for malignant pulmonary nodules. Tc-99m-HMPAO was concentrated in 62% of 13 patients with malignant pulmonary nodules, which was slightly higher than Ga-67 in 54% of 28 patients. In an analysis of the histologic types of lung cancer, the sensitivity of Tl-201 was not significantly different in all types. On the other hand, Ga-67 was positive only in 25% of 12 patients with adenocarcinoma. A combination of SPECT and Tl-201 is the best choice among routine scintigraphic techniques for depicting malignant pulmonary nodules. The Tl-201 SPECT image may play a complementary role in the characterization of pulmonary nodules which are revealed on a plain radiograph and computed tomography.

Adult↗
PubMed1992

[Clinical usefulness of exercise/rest 99mTc-teboroxime SPECT imaging: results of a Japanese multi-center phase II study].

99mTc-Teboroxime [Chloro[tris(cyclohexyldioxime)methaneboronic acid] (99mTc)technetium], a perfusion agent for myocardial imaging, has a distinct advantage over 201Tl because of its very high myocardial extraction and is a 99mTc compound ideal for gamma camera imaging. This agent also demonstrates rapid myocardial washout, which allows completion of exercise and rest imaging studies in a short interval (to 1 hour). However, the rapid washout necessitates the completion of image acquisition very quickly after injection and therefore may require nonconventional SPECT imaging. In this Phase II study we evaluate the safety and efficacy of 99mTc-Teboroxime to detect coronary artery disease by exercise and rest SPECT imaging in 38 patients with prior myocardial infarction, 31 patients with angina pectoris, and 4 patients with non-coronary cardiac diseases. The 99mTc-Teboroxime dose used was 370-740 MBq in each study. The findings were compared with coronary angiography or 201Tl exercise and redistribution SPECT. No significant adverse reactions or laboratory abnormalities attributable to 99mTc-Teboroxime were observed. The quality of SPECT images was optimal in 62.5% of all patients. The relatively large population of suboptimal cases (37.5%) was attributed to the delay of the start and prolongation of the image acquisition time. In 85.7% of patients whose imaging was started within 5 minutes and completed within 11 minutes after injection, optimal quality was observed. Thus, 99mTc-Teboroxime SPECT requires the rapid completion of image acquisition after injection to achieve optimal image quality. Abnormalities of 99mTc-Teboroxime distribution were detected in 97.1% and 62.1% of patients with prior myocardial infarction or angina pectoris, respectively. The concordance with coronary angiography was 84.4% and 68.0%, and with 201Tl was 78.1% and 74.1%, respectively. Although standardization of the image protocol suitable for this agent is needed for the next study, these high correlations suggest the potential usefulness of 99mTc-Teboroxime SPECT imaging.

Adult↗
PubMed1992

[Diagnostic value of a new myocardial perfusion agent, 99mTc-teboroxime (SQ30,217) in patients with coronary artery disease, utilizing a SPECT imaging protocol: a multicenter phase III clinical trial].

Technetium-99m teboroxime (TEBO) is a new technetium-based myocardial perfusion imaging agent, which has high myocardial extraction and rapid myocardial washout. Its rapid myocardial washout may necessitate rapid imaging protocols. This study was designed to perform exercise/rest SPECT imaging protocols with rapid data acquisition (from 2.8 +/- 1.4 min to 11.2 +/- 4.1 min after injection) in 171 patients with coronary artery disease, 15 patients with cardiomyopathy and 8 patients with other heart disease. The rapid imaging protocols resulted in a high prevalence of good image quality. The diagnostic value of TEBO was recognized from the high concordance of image findings with thallium-201 (201Tl) scintigraphy, 88.2% in the exercise protocol and 89.9% in the rest protocol. Also, the sensitivity and specificity of TEBO for detecting coronary artery disease were comparable (86.6% and 53.9%, respectively) with those of 201Tl (90.7% and 46.2%, respectively). No toxic effects of TEBO were observed in subjective and objective clinical findings and blood examinations. TEBO was finally evaluated to be useful in 98.4% of the patients. Thus, this agent has good clinical potential for myocardial perfusion imaging.

Aged↗
PubMed1991

Single photon emission computed tomography with Tc-99m-dimercaptosuccinic acid in patients with upper urinary tract infection and/or vesicoureteral reflux.

By means of Tc-99m dimercaptosuccinic acid (DMSA) scintigraphy, an established method for assessing renal cortical damage, we evaluated the pick-up rate for renal defects (scars) by single photon computed tomography (SPECT) and planar images of 10 normal volunteers, and 58 patients (70 scintigrams) with upper urinary tract infections, most of whom had a history of vesicoureteral reflux (VUR). The positive study rate for renal defects depended on the severity of VUR. The overall positive rates for renal cortical defects obtained by DMSA SPECT imaging and DMSA planar imaging were 60% and 43%, respectively, and the difference between these was significant (p less than 0.005). The mean absolute individual renal uptake (/injected dose) at 2 hours post-injection was decreased in kidneys with defects detected by SPECT alone. The positive study rate for intravenous urography (IVU) depended on the grade of VUR and was 15% overall. DMSA SPECT imaging detects renal cortical defects at greater frequency than previously achieved.

Adolescent↗
PubMed1991

Tc-99m labeled tissue-type plasminogen activator: preparation, stability and preliminary imaging of thrombus-bearing rats.

Tissue-type plasminogen activator (t-PA) is a thrombolytic agent that directly binds to fibrin formed in clots. In terms of radiolabeling and nuclear imaging, t-PA has several advantages in Tc-99m labeling: it is stable in acidic solution at pH 3, which is suitable for labeling Tc-99m by a method of stannous reduction and blood disappearance after administration is rapid, which is desirable for imaging targets using short-lived radionuclides. Recombinant t-PA was labeled with Tc-99m by a method of stannous reduction without significant degradation of biochemical activity, over 95% of which was retained after the labeling procedure. Labeling efficiency in paper chromatography was over 98%. The moiety of hydrolyzed Tc-99m that was not eluted through the Sephadex column was estimated to be less than 10%. Tc-99m labeled t-PA, however, appeared to become unstable when diluted with normal saline. Nevertheless, in in vitro fibrin binding, Tc-99m labeled t-PA showed high affinity with fibrin: 80% of 100 ng/ml of Tc-99m t-PA bound to 10(-5) mol of the fibrinogen. Preliminary animal studies also showed a concentration of Tc-99m labeled t-PA at fresh thrombi formed in the inferior vena cava. Tc-99m labeled t-PA appears to have potential for thrombus imaging and the preparation of an instant kit.

Animals↗
PubMed1991

[Adrenocortical scintigraphy to evaluate incidental adrenal mass (incidentaloma) discovered on computed tomography].

To assess the nature of adrenal mass incidentally discovered on computed tomography, adrenocortical scintigraphy with I-131-6 beta-iodomethyl-19-norcholest-5(10)-en-3 beta-ol (I-131 Adosterol) in 29 patients was retrospectively reviewed. All patients had no clinical symptoms and biochemical evidence of adrenal hyperfunction. Six of them had extra-adrenal malignancy. Increased tracer uptake on the side of adrenal mass was observed in 13 patients (concordant group): cortical adenoma in 8, macronodular hyperplasia in 1, no growing tumor in 1, and no further examination in the remaining 3 patients. No cancer patients were included in the concordant group. Symmetric uptake was seen in 9 patients (symmetric group): 1 cortical adenoma and 1 ganglioneuroma, 6 no growing tumor (two of them had malignancy), and no further examination in 1 patient. Decreased uptake were shown in 7 patients (dis-concordant group): metastasis in 4, adrenal cyst in 2, and no growing tumor in 1. Adrenocortical scintigraphy was helpful in distinguishing benign functioning adrenal masses from non-functioning adrenal masses such as metastatic tumor and cyst.

Adenoma↗
PubMed1990

[Quantitation of absolute and relative renal uptake using 99mTc-DMSA: sequential change in time and correlation with 99mTc-DTPA uptake].

A renal uptake of 99mTc-DMSA as a function of time and correlation between 99mTc-DMSA and 99mTc-DTPA in renal uptake were discussed. The absolute renal uptake of 99mTc-DMSA calculated by complete correction of tissue attenuation and physical decay showed increase by 5 hours after the administration, except one case with congestive heart failure. The net renal counts attained a maximum between 2 to 3 hours after the administration. There was a good correlation (r -0.992, p less than 0.001) between the relative renal uptake of 99mTc-DMSA (2 hour) and that of 99mTc-DTPA (2-3 min). On the contrary, the absolute renal uptake of 99mTc-DMSA as a indicator of total renal function showed a poor correlation (r = 0.419) to GFR calculated from 99mTc-DTPA. The results indicate that the relative renal uptake of 99mTc-DMSA is a reliable quantitative parameter for split renal function. However, the absolute renal uptake of 99mTc-DMSA may be suggested to be a different renal functioning indicator from GFR calculated from 99mTc-DTPA.

Adolescent↗
PubMed1990

[Captopril-enhanced renography using 99mTc-DTPA in renovascular hypertensive patients].

Dynamic renal scintigraphy with 99mTc-DTPA before (baseline renography: BS-RG) and 1 hour after administration of 25 mg to 50 mg of captopril (captopril-enhanced renography: CP-RG) was performed in a selected series of 18 patients suspected of having renovascular hypertension. Final diagnosis was made by angiography and further clinical follow-up. Eight patients were considered as renovascular hypertension (RVH), 6 with bilateral renal artery stenosis (BRAS) and 2 with unilateral renal artery stenosis (URAS). The remaining 10 patients were non-renovascular (non-RVH). Two criteria were prospectively employed for evaluating positive response induced by captopril. Glomerular filtration rate (GFR) on BS-RG (GFRbase) and on CP-RG (GFRcap) was estimated by early (120-180 seconds) DTPA uptake by the kidney, and then captopril response rate (CRR) was calculated in the following: CRR = (GFRcap-GFRbase)/GFRbase X 100 (%). CP-RG was considered positive when it was less than 20%. Renogram shape was also independently evaluated. CP-RG was also considered positive when either a delay of time to peak activity of more than 5 min or conversion of renogram shape to an obstructive or non-functioning pattern was observed. The sensitivity and specificity of CRR and change in renogram were 50% and 80%, 63% and 100%, respectively. In BRAS, positive response was observed in the unilateral kidney alone which maintained relatively a good renal function. CP-RG could not differentiate RVH with URAS from that with BRAS. Four patients were followed after the surgical or angioplastic treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1990

[Dynamic renal scintigraphy of dissecting aneurysm of abdominal aorta].

Dynamic renal scintigraphy on 15 patients of dissecting aneurysm of abdominal aorta extending below the renal arteries were retrospectively studied. The results were reviewed and classified into 3 types according to perfusion images and parenchymal tissue uptake: Type A: symmetric perfusion and parenchymal tissue uptake, Type B: asymmetrical perfusion and parenchymal tissue uptake, Type C: Delayed perfusion of one kidney and symmetric parenchymal tissue uptake. The number of patients who showed Type A, Type B, and Type C were 3 cases, 6 cases, and 6 cases, respectively. In all Type A and 3 of Type B, perfusion of bilateral renal arteries was mainly from true lumen. In the remaining 3 cases of Type B, 2 had one renal artery obstructed with thrombus; 1 had a deformity of one kidney (the blood supply was mainly from a false lumen), suggestive of renal infarction. On the other hand, in all 6 Type C cases, the renal artery where perfusion was delayed was apparently supplied from false lumen. It is suggested in this retrospective study that the findings in Type C, where delayed perfusion of one kidney and symmetric parenchymal tissue uptake were found, were due to the presence of delayed flow through the false lumen; and therefore, specific to cases where the main blood supply of one renal artery from false lumen.

Adult↗