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H Atsumi

Publications and source records attributed to H Atsumi.

At least 19 recordsLinked to original sources
PubMed1999

Delayed ischemic neurological deficit of short duration in patients with subarachnoid hemorrhage.

We retrospectively examined the duration of delayed ischemic neurological deficits (DIND) attributed to vasospasm following subarachnoid hemorrhage (SAH) in order to delineate the nature and involved factors. Among 605 patients with SAH, 201 developed DIND, and 137 of these had undergone early aneurysmal obliteration. In these 137, duration of DIND was clearly determined in 67 cases. Hypervolemic therapy was instituted only after the onset of DIND. In the 67 patients, the mean duration of DIND was 5.2 days (ranging from 2 to 13 days); 22 patients had DIND lasting only 2 to 3 days, 26 patients had DIND lasting 4 to 6 days, and in 19, DIND lasted 7 to 13 days. Clinical factors associated with short DIND duration (2 to 3 days) as determined by multivariate analysis included internal carotid artery or middle cerebral artery aneurysm, age under 60, and a good World Federation of Neurological Surgeons grade on admission. No patients developed pulmonary edema from hypervolemic therapy, and the outcomes of all 67 patients were extremely favorable. In SAH patients developing DIND after early aneurysmal surgery, 16% (22 of 137) had a documented brief duration of DIND. We believe DIND rapidly improved and resolved with hypervolemic therapy because antecedent brain damage from SAH or surgical manipulation had been minimal.

Female↗
PubMed1998

A simple method of scalp localization using multiplanar reconstruction of MR images.

BACKGROUND: Image-based scalp localization methods currently used are complex and not standardized. The authors have developed a simple yet accurate method for craniotomy localization using multiplanar reconstruction (MPR) algorithms. METHODS: In this method, the goal is to localize a projected point (defined as T) of the center of the lesion on the scalp. An oblique coronal plane is reformatted using a patient's magnetic resonance (MR) images with MPR algorithms to include both the center of the lesion and bilateral external auditory meati. Then the distance between T and the ipsilateral external auditory meatus or sagittal suture (defined as S) is measured along the scalp contour in the plane. The distance between the bregma and S is also measured. These distances are used for scalp localization, using a tape measure in the operating room. RESULTS: We have had successful scalp localization in six clinical cases. It took about 3 min to measure each distance on the MR console. CONCLUSION: This method for craniotomy planning using MPR algorithms is simple and sufficiently accurate.

Craniotomy↗
PubMed1998

Three-dimensional multi-scale line filter for segmentation and visualization of curvilinear structures in medical images.

This paper describes a method for the enhancement of curvilinear structures such as vessels and bronchi in three-dimensional (3-D) medical images. A 3-D line enhancement filter is developed with the aim of discriminating line structures from other structures and recovering line structures of various widths. The 3-D line filter is based on a combination of the eigenvalues of the 3-D Hessian matrix. Multi-scale integration is formulated by taking the maximum among single-scale filter responses, and its characteristics are examined to derive criteria for the selection of parameters in the formulation. The resultant multi-scale line-filtered images provide significantly improved segmentation and visualization of curvilinear structures. The usefulness of the method is demonstrated by the segmentation and visualization of brain vessels from magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA), bronchi from a chest CT, and liver vessels (portal veins) from an abdominal CT.

Bronchography↗
PubMed1998

Cardiac sympathetic nervous disintegrity is related to exercise intolerance in patients with chronic heart failure.

The aim of this study was to clarify the relationship between cardiac sympathetic nervous activity assessed by 123I-MIBG imaging and exercise capacity in patients with congestive heart failure. The subjects were 24 patients with heart failure (NYHA class II to III) and 7 normal controls. A dose of 148 MBq of 123I-MIBG was administered intravenously, and 5-min anterior planar images were obtained 20 min (early) and 4 h (delayed) after the injection of 123I-MIBG. Regions of interest were placed over the left ventricle and mediastinum, and the heart-to-mediastinum ratio (H/M ratio) was calculated as a fraction of the mean counts per pixel in the heart divided by those in the mediastinum. The washout rate from the myocardium was determined by: (early counts delayed counts) x 100/early counts (%). Treadmill exercise tests were performed using a ramp method within 1 week of the 123I-MIBG studies. During exercise, expired gas was analysed, and peak VO2 and VO2 at the anaerobic threshold (ATVO2) were measured. A significant linear correlation was found between the H/M ratio on delayed 123I-MIBG images and exercise duration (r = 0.48, P < 0.05), peak VO2 (r = 0.49, P < 0.05) and ATVO2 (r = 0.56, P < 0.01). The washout rate of 123I-MIBG was inversely correlated with exercise duration (r = -0.45, P < 0.05), peak VO2 (r = -0.51, P < 0.01), and ATVO2 (r = -0.50, P < 0.05). In conclusion, enhanced cardiac sympathetic nervous activity relates to exercise intolerance in patients with congestive heart failure. The non-invasive assessment of cardiac sympathetic nervous activity by 123I-MIBG can predict exercise capacity in human heart failure.

3-Iodobenzylguanidine↗
PubMed1998

Quantitative assessment of myocardial 99mTc-sestamibi uptake during exercise: usefulness of response rate for assessing severity of coronary artery disease.

An increase of 99mTc-sestamibi uptake in the myocardium during exercise was defined as a response rate, and the feasibility of a response rate for detecting coronary artery disease (CAD) was tested. Eighty-seven patients with suspected CAD had myocardial perfusion imaging with 99mTc-sestamibi during exercise and at rest. A dose of 370 MBq of 99mTc-sestamibi was injected at the maximal level of exercise, and a myocardial image was obtained 90 min later (exercise image). Then, 740 MBq of 99mTc-sestamibi was administered at rest, and myocardial imaging was repeated (rest image). The exercise and rest images were corrected for physical decay and injected doses, and the exercise image was subtracted from the rest image to obtain the corrected rest image. A response rate was calculated as follows: (exercise image-corrected rest image)x100/corrected rest image (%). The global response rates of 20 patients without significant coronary stenosis (< or =50%) were higher than those of 67 patients with significant coronary stenosis (81+/-33% and 50+/-28%, p<0.01). Global response rates were correlated with the maximal rate pressure products during exercise (r=0.56, p<0.01) and delta rate pressure products (r=0.53, p<0.01). Regional response rates in myocardial areas perfused by stenotic coronary arteries of < or =50%, 75%, 90% and 99-100% were 60+/-24%,* 56+/-33%,* 40+/-23%* and 30+/-23%,* respectively, (*p<0.01 vs without significant coronary stenosis). The response rates decreased as the severity of coronary artery stenosis advanced, and distinguished between coronary stenoses of graded severity. Accordingly, the response rate from myocardial perfusion imaging with 99mTc-sestamibi may provide complementary information to the conventional inspection with myocardial tomography regarding the severity of CAD.

Coronary Disease↗
PubMed1998

Myocardial tomography with technetium-99m-tetrofosmin during intravenous infusion of adenosine triphosphate.

UNLABELLED: The purpose of this study was to determine the biodistribution of 99mTc-tetrofosmin during intravenous infusion of adenosine triphosphate (ATP) and to evaluate the potential diagnostic value of myocardial tomography with 99mTc-tetrofosmin during ATP infusion for the detection of coronary artery disease. METHODS: Myocardial 99mTc-tetrofosmin imaging with ATP infusion and coronary arteriography were performed on 65 patients with suspected coronary artery disease. ATP was infused intravenously at a rate of 0.16 mg/kg/min for 5 min, and 370 MBq of 99mTc-tetrofosmin was injected 3 min after the start of ATP infusion. Myocardial SPECT imags were obtained 60 min later. Then, 740 MBq of 99mTc-tetrofosmin was administered at rest, and myocardial SPECT was repeated. Regional uptakes of 99mTc-tetrofosmin were scored from 4, normal, to 0, no activity. Serial 5-min planar images were obtained in the anterior projection at 15, 30, 45 and 60 min after the 99mTc-tetrofosmin injection in 10 patients. Heart-to-lung and heart-to-liver count ratios were defined from the serial planar images. RESULTS: Adverse effects of ATP infusion were mild and transient. A heart-to-lung ratio after ATP infusion was high even at 15 min (3.40 +/- 0.33) and gradually increased with time. A heart-to-liver ratio after ATP was 0.53 +/- 0.40 at 15 min and increased with time. A heart-to-liver ratio reached 0.99 +/- 0.25 (p < 0.01) after 45 min and 1.32 +/- 0.36 (p < 0.01) after 60 min. The sensitivity and specificity for detecting coronary artery disease by myocardial SPECT with ATP were 89% (39/44) and 86% (18/21), respectively. CONCLUSION: This study shows the favorable biodistribution of 99mTc-tetrofosmin after intravenous infusion of ATP. A one-day imaging protocol of 99mTc-tetrofosmin tomography with ATP is feasible and has high diagnostic accuracy for coronary artery disease.

Adenosine Triphosphate↗
PubMed1997

Use of cortical surface vessel registration for image-guided neurosurgery.

OBJECTIVE: We have treated patients with brain surface tumors by using video registration of a three-dimensional image to the surgical field, to identify eloquent cortices, localize the lesions, and define the tumor margins. "Skin-to-skin" registration using the skin surface to produce alignment was performed earlier but was difficult in areas with few prominent registration landmarks. For this reason, "vessel-to-vessel" registration using the cortical vessels as fiducials was applied to 17 cases, to improve accuracy. This article presents the advantages and limitations of vessel-to-vessel registration, as determined from the data for these cases. The accuracy is also estimated. METHODS: A three-dimensional model was reconstructed from magnetic resonance imaging data, and a two-dimensional projection was superimposed on the video image of the actual surgical field. The tumor was resected with guidance from the registered video image. The two-dimensional projection accuracy of vessel-to-vessel registration was compared with that of skin-to-skin registration by using a phantom study. RESULTS: All 17 tumors underwent gross total resection, and the patients experienced no major permanent neurological deficits. In the phantom study, the two-dimensional, projected, target registration error of a tumor with skin-to-skin registration was estimated as 8.9 +/- 5.3 mm and that with vessel-to-vessel registration was 1.3 +/- 1.4 mm (99th percentile confidence intervals, 24.8 and 5.5 mm, respectively). CONCLUSION: Video registration using cortical surface vessels is practical and improves two-dimensional projection accuracy significantly, compared with skin registration.

Adolescent↗
PubMed1997

Computer-assisted surgical planning for cerebrovascular neurosurgery.

OBJECTIVE: We used three-dimensional reconstructed magnetic resonance images for planning the operations of 16 patients with various cerebrovascular diseases. We studied the cases of these patients to determine the advantages and current limitations of our computer-assisted surgical planning system as it applies to the treatment of vascular lesions. METHODS: Magnetic resonance angiograms or thin slice gradient echo magnetic resonance images were processed for three-dimensional reconstruction. The segmentation, based on the signal intensities and voxel connectivity, separated each anatomic structure of interest, such as the brain, vessels, and skin. A three-dimensional model was then reconstructed by surface rendering. This three-dimensional model could be colored, made translucent, and interactively rotated by a mouse-controlled cursor on a workstation display. In addition, a three-dimensional blood flow analysis was performed, if necessary. The three-dimensional model was used to assist in three stages of surgical planning, as follows: 1) to choose the best method of intervention, 2) to evaluate surgical risk, 3) to select a surgical approach, and 4) to localize lesions. RESULTS: The generation of three-dimensional models allows visualization of pathological anatomy and its relationship to adjacent normal structures, accurate lesion volume determination, and preoperative computer-assisted visualization of alternative surgical approaches. CONCLUSION: Computer-assisted surgical planning is useful for patients with cerebrovascular disease at various stages of treatment. Lesion identification, therapeutic and surgical option planning, and intraoperative localization are all enhanced with these techniques.

Adolescent↗
PubMed1997

Three-dimensional reconstruction and surgical navigation in pediatric epilepsy surgery.

We have used MRI-based three-dimensional (3D) reconstruction and a real-time, frameless, stereotactic navigation device to facilitate the removal of seizure foci in children suffering from intractable epilepsy. Using this system, the location of subdural grid and strip electrodes is recorded on the 3D model to facilitate focus localization and resection. Ten operations were performed, including 2 girls and 8 boys ranging in age from 3 to 17, during which 3D reconstruction and surgical instrument tracking navigation was used. In all the cases, the patients tolerated the procedure well and showed no postoperative neurological deficits. We believe this to be a valuable tool for a complete and safe resection of seizure foci, thereby reducing the incidence of postoperative neurological deficits and significantly improving the overall quality of life of the patients.

Adolescent↗
PubMed1997

Fatty acid metabolic imaging with iodine-123-BMIPP for the diagnosis of coronary artery disease.

UNLABELLED: Iodine-123-BMIPP kinetics under high glucose levels were examined. The feasibility of 123I-BMIPP imaging after oral glucose loading for the detection of impaired fatty acid metabolism was tested in patients with coronary artery disease. METHODS: Fatty acid metabolic imaging with 123I-BMIPP was performed on 29 patients in the fasting state and repeated after oral glucose loading. Myocardial SPECT images were obtained 20 min and 4 hr after the injection of 123I-BMIPP. Myocardial uptake of 123I-BMIPP was calculated by a Ishii-Macintyre method and the clearance of 123I-BMIPP from the myocardium was determined as (early counts-delayed counts) x 100/early counts. Regional accumulation of 123I-BMIPP was scored semiquantitatively from 0 (normal) to 4 (no activity), and the sum of regional scores in each patient was defined as a total defect score (TDS). RESULTS: Total myocardial uptake of 123I-BMIPP was 1.7% +/- 0.4% in the fasting state and 1.6% +/- 0.3% after oral glucose loading (p < 0.05). Iodine-123-BMIPP clearance from the myocardium was faster after glucose loading than in the fasting state (27% +/- 8% versus 11% +/- 6%, p < 0.01). After glucose loading, 123I-BMIPP clearance was faster in the ischemic myocardium (defined as areas perfused by stenosed coronary artery exceeding 90%) than in the nonischemic myocardium (33% +/- 8% versus 25% +/- 9%, p < 0.05). TDS in the ischemic myocardium increased from 1.8 +/- 0.4 in the fasting state to 2.1 +/- 0.4 after glucose loading (p < 0.01). The sensitivity for detecting coronary stenosis exceeding 90% increased from 55% (11/20) in the fasting state to 75% (15/20) after glucose loading without a loss of specificity (78%, 7/9). CONCLUSION: Oral glucose loading enhanced the detection of areas with impaired fatty acid metabolism due to coronary artery narrowing. Iodine-123-BMIPP imaging with oral glucose loading may be a new approach for the noninvasive diagnosis of coronary artery disease.

Adult↗
PubMed1997

ACE inhibition reduces cardiac iodine-123-MIBG release in heart failure.

UNLABELLED: Radioiodinated metaiodobenzylguanidine (123I-MIBG), an analog of norepinephrine, has been used to assess cardiac sympathetic nerve activity. Decreased myocardial accumulation and enhanced washout of 123I-MIBG have been reported in patients with congestive heart failure (CHF). The purpose of this study was to determine whether angiotensin converting enzyme (ACE) inhibition reduced 123I-MIBG release and improved cardiac 123I-MIBG accumulation in patients with CHF. METHODS: Twenty-nine patients receiving conventional treatment for CHF, New York Heart Association (NYHA) functional class 2-3, were studied. Nineteen patients received additional treatment with enalapril, an ACE inhibitor, and 10 patients who were treated with conventional therapy alone were defined as a control group. Iodine-123-MIBG imaging and echocardiography were performed on all patients before treatment and repeated after 9.1 +/- 3.0 mo of treatment. Images were obtained 30 min and 4 hr after injection of 123I-MIBG, and a heart to mediastinum (H/M) ratio was defined to quantify cardiac 123I-MIBG uptake as a fraction of the mean counts per pixel in the heart divided by those in the mediastinum. The washout rate of 123I-MIBG from the heart was calculated as follows: (early counts - delayed counts)/early counts x 100(%). RESULTS: In patients with enalapril group, the H/M ratio of 123I-MIBG was increased after treatment (early image: 1.60 +/- 0.22 vs. 1.73 +/- 0.28, p < 0.05, delayed image: 1.63 +/- 0.28 vs. 1.82 +/- 0.33, p < 0.01). The washout rate of 123I-MIBG was reduced from 38% +/- 11% to 30% +/- 12% after treatment (p < 0.01). However in the conventional therapy group, the H/M ratios in the early and delayed images (early image: 1.58 +/- 0.31 vs. 1.52 +/- 0.23, delayed image: 1.49 +/- 0.27 vs. 1.49 +/- 0.25) and the washout rate (34% +/- 8% vs. 33% +/- 7%) remained unchanged after treatment. In patients with an increased H/M ratio of enalapril group (n = 13), a left ventricular ejection fraction increased from 48% +/- 12% to 55% +/- 9% (p < 0.01) after treatment. CONCLUSION: ACE inhibition reduces cardiac 123I-MIBG release and thus lowers cardiac sympathetic nerve activity. Iodine-123-MIBG may be helpful in evaluating the therapeutic effects of ACE inhibition on the cardiac sympathetic nervous system in patients with CHF.

3-Iodobenzylguanidine↗
PubMed1997

Iodine-123-BMIPP imaging in unstable angina: a guide for interventional strategy.

UNLABELLED: The aim of this study was to clarify the clinical implications of decreased myocardial uptakes of 123I-labeled beta-methyl-p-iodophenyl-pentadecanoic acid (123I-BMIPP) in patients with unstable angina. METHODS: Fatty acid metabolic imaging with 123I-BMIPP was performed in 20 patients with unstable angina during the pain-free state. Regional uptakes of 123I-BMIPP were scored semiquantitatively, and clinical characteristics and angiographic findings were compared between the patients with the normal and abnormal 123I-BMIPP images. RESULTS: There were 9 patients with normal and 11 patients with abnormal 123I-BMIPP images. Severe coronary stenosis exceeding 90% (91% compared with 44%, p < 0.05) and 99% (82% compared with 0%, p < 0.01) and collateral opacification (36% compared with 0%, p < 0.05) were more frequently observed in patients with abnormal 123I-BMIPP images than in those with normal images. Percutaneous transluminal coronary angioplasty or coronary artery bypass grafting was performed in 22% of patients with normal 123I-BMIPP images and in 82% of patients with abnormal 123I-BMIPP images (p < 0.01). CONCLUSION: Fatty acid metabolic imaging with 123I-BMIPP can determine the functional severity of coronary artery disease and is helpful for a clinical judgment in interventional treatment.

Aged↗
PubMed1996

Multi-modal volume registration by maximization of mutual information.

A new information-theoretic approach is presented for finding the registration of volumetric medical images of differing modalities. Registration is achieved by adjustment of the relative position and orientation until the mutual information between the images is maximized. In our derivation of the registration procedure, few assumptions are made about the nature of the imaging process. As a result the algorithms are quite general and can foreseeably be used with a wide variety of imaging devices. This approach works directly with image data; no pre-processing or segmentation is required. This technique is, however, more flexible and robust than other intensity-based techniques like correlation. Additionally, it has an efficient implementation that is based on stochastic approximation. Experiments are presented that demonstrate the approach registering magnetic resonance (MR) images with computed tomography (CT) images, and with positron-emission tomography (PET) images. Surgical applications of the registration method are described.

Brain↗
PubMed1996

Fatty acid metabolic imaging with 123I-BMIPP for the diagnosis of coronary artery disease: application to patients with diabetes mellitus and hyperlipidaemia.

The aim of this study was to assess the relation of plasma substrate concentration to 123I-beta-methyliodophenyl-pentadecanoic acid (123I-BMIPP) kinetics in the myocardium and to test the application of 123I-BMIPP imaging to patients with diabetes mellitus (DM) and/or hyperlipidemia (HL). 123I-BMIPP imaging was performed on 78 patients with suspected coronary artery disease, 22 with HL, 11 with DM, 12 with HL and DM, and 33 with neither HL or DM. Significant coronary stenosis (defined as > or = 50% of luminal diameter) was documented in 49 patients. After an overnight fast, blood samples were drawn for blood glucose, insulin, cholesterol, triglycerides and free fatty acid levels. Then, 148 MBq 123I-BMIPP was injected intravenously and flushed rapidly with saline. Data were obtained for 60s in a standard anterior projection in list mode, at a rate of 1 frame per second. Myocardial single photon emission tomographic (SPET) images were obtained 20 min and 4 h post-injection. The myocardial uptake of 123I-BMIPP was calculated using the Ishii-MacIntyre method. Regional accumulation of 123I-BMIPP was scored semi-quantitatively from 0 (normal) to 4 (no activity), and the sum of regional scores in each patient was defined as the total defect score (TDS). Myocardial uptake and clearance of 123I-BMIPP had no relation to the levels of blood glucose, insulin, cholesterol, triglycerides or free fatty acids. Myocardial uptake and clearance of 123I-BMIPP, TDS and the sensitivity of detecting significant coronary stenosis were not significantly different between the four groups of patients. We conclude that 123I-BMIPP can be used to detect impaired fatty acid metabolism in patients with diabetes mellitus and/or hyperlipidaemia.

Biological Transport, Active↗
PubMed1996

Delayed metabolic recovery of hibernating myocardium after percutaneous transluminal coronary angioplasty: assessment with iodine-123-betamethyl-p-iodophenyl-pentadecanoic acid imaging.

The time course of improvement in fatty acid metabolism after percutaneous transluminal coronary angioplasty (PTCA) was investigated using echocardiography and fatty acid metabolic imaging with iodine-123-betamethyl-p-iodophenyl-pentadecanoic acid (123I-BMIPP) before, 1 week and 3 months after PTCA in 31 patients with angina pectoris. Decreased left ventricular wall motion before PTCA improved 1 week after PTCA in 13 of 31 patients. 123I-BMIPP uptake was reduced in these 13 patients before PTCA, and did not improve 1 week after PTCA. Decreased myocardial uptake of 123I-BMIPP improved 1 week after PTCA in eight of 23 patients (group A). Thirteen patients in whom 123I-BMIPP uptake had not improved 1 week after PTCA showed a delayed recovery of 3 months after PTCA (group B). All patients in groups A and B showed improvement in wall motion 1 week after PTCA. Patients in group B had a higher incidence of unstable angina (77% vs 25%, p < 0.01), 99% or 100% stenosis (62% vs 13%, p < 0.01) and collateral vessels (46% vs 13%, p < 0.05) than those in group A. Serial fatty acid metabolic imaging with 123I-BMIPP after PTCA showed delayed metabolic recovery after improvement in wall motion in 13 of 23 patients. The presence of severe myocardial ischemia before PTCA enhanced the chronological discrepancies between the recovery of wall motion and fatty acid metabolism.

Aged↗
PubMed1996

[Quantitative assessment of an increase of myocardial 99mTc-MIBI accumulation during exercise--usefulness of response rate].

The increase of myocardial 99mTc-MIBI accumulation during exercise was evaluated quantitatively, and the feasibility of response rate as a noninvasive marker of coronary stenosis was tested. Myocardial perfusion imaging with 99mTc-MIBI during exercise and at rest was performed in patients with suspected coronary artery disease. A dose of 296 MBq of 99mTc-MIBI was injected intravenously at maximal treadmill exercise, and myocardial image was obtained 90 min later (1st image). Then, 740 MBq of 99mTc-MIBI was administered at rest, and myocardial image was repeated (2nd image). These images were corrected for a decay and injected dose, and the 1st image was subtracted from the 2nd image to obtain the rest image. An increase of myocardial accumulation of 99mTc-MIBI during exercise was defined as (exercise image-rest image) x 100/rest image (response rate). A response rate of a patient with normal coronary artery was 102%, whereas a response rate in the area of severe coronary stenosis was 21% in a patients with angina pectoris. After successful PTCA to a stenosed coronary artery, a response rate increased to 75% in this patient. Coronary perfusion reserve during exercise can be assessed noninvasively by 99mTc-MIBI. Response rate of 99mTc-MIBI provides additional information to conventional perfusion imaging and may be a new marker of severity of coronary artery disease.

Biomarkers↗
PubMed1995

Error analysis of table look-up method for cerebral blood flow measurement by 123I-IMP brain SPECT: comparison with conventional microsphere model method.

While N-isopropyl-p-[123I]iodoamphetamine (IMP) is commonly used as a flow tracer, significant clearance from the brain causes underestimation of CBF as compared with true CBF when conventional microsphere model analysis is applied. We previously reported a simple "table look-up" method for CBF measurement using IMP taking into account this clearance effect. The method is based on a two-compartment model, the K1 (corresponding to CBF) and k2 constants being obtained from a table from the ratio of the 1st SPECT (40 min) to the 2nd SPECT (180 min) counts. Arterial input data used were obtained by one point blood sampling 10 min after IMP infusion against the standard input function. In the present study, this approach was compared with conventional microsphere model analysis. For 30 subjects, the latter method entailed 8 min continuous arterial blood sampling after IMP infusion and the use of SPECT data at the end of this period, calibrated by a count ratio of 8 min/40 min planar images of whole brains. A good correlation was observed between the two methods (r = 0.88), but an overestimation of table look-up method CBF as compared with microsphere model CBF was observed contrary to theoretical predictions. Limitations in the estimation of SPECT data at 8 min, obtained with SPECT data at 40 min for calibration of the count ratio of 8 min/40 min whole brain planar images, might be responsible for this.

Amphetamines↗