Biomedical subjects

Shin-ichiro Kumita

Publications and source records attributed to Shin-ichiro Kumita.

18 recordsLinked to original sources

PubMed2006

Stereotactic statistical imaging analysis of the brain using the easy Z-score imaging system for sharing a normal database.

Statistical brain imaging analysis has good objectivity and reproducibility. In Japan, statistical parametric mapping (SPM) and three-dimensional stereotactic surface projections (3D-SSP) are used nationwide as statistical imaging analysis with standard brain coordinates. They often help to interpret brain single photon emission computed tomography (SPECT) images by avoiding possible pitfalls (e.g., effects of aging, atrophy) with which clinicians are unfamiliar. However, this type of analysis presents a problem: statistical processing requires many normal subject images. The easy Z-score imaging system (eZIS) is one of the statistical analysis methods that uses SPM processing in normalization and smoothing, and it has the function of image conversion leading to statistical analysis without a control database. Therefore, statistical analysis can be used in clinical practice by sharing a prepared normal database. By unifying the image quality by processing a shared database, this program has great potential for sharing patient imaging data in many hospitals. It is expected that the eZIS will help perform detailed analysis in many functional diseases in collaborative studies. This article describes the interpretation of brain SPECT images and suggests the usefulness and potential of eZIS.

Aging↗

PubMed2006

Clinical applications of ECG-gated myocardial perfusion SPECT.

Erectrocardiogram (ECG)-gated myocardial perfusion single photon emission computed tomography (SPECT) can be used to assess myocardial perfusion and left ventricular function simultaneously. Various clinical applications of gated SPECT and their usefulness have been reported. The functional variables that can be determined with gated SPECT have been limited to systolic indices. Therefore, we evaluated left ventricular diastolic function with gated SPECT using data obtained from various frames per cardiac cycle and found that date generated from 32-frames are suitable for clinical use. Serial assessment of left ventricular function was also performed during bicycle exercise and dobutamine stress by means of gated SPECT using short-time data collection. These techniques, therefore, have the potential to provide useful information for evaluating myocardial conditions, such as hibernation and residual ischemia in infarct areas. Recently, we have developed a new technique for three-dimensional registration of CT coronary angiography (CTCA) and ECG-gated myocardial perfusion SPECT. This technique of registration may assist the integration of information from gated SPECT and CTCA and may have clinical application for the diagnosis of ischemic heart disease. These various applications would contribute to the development of nuclear cardiology.

Coronary Angiography↗

PubMed2006

Evaluation of no-reflow phenomenon using 201TlCl/123I-BMIPP dual-isotope myocardial SPECT.

OBJECTIVES: We assessed the usefulness of (201)thallous chloride (TlCl)/(123)I-beta-methyl iodophenyl pentadecanoic acid (BMIPP) dual-isotope single-photon emission computed tomography (SPECT) to identify the "no-reflow phenomenon," defined as inadequate myocardial perfusion through a given segment of the coronary circulation without angiographic evidence of mechanical vessel obstruction. METHODS: (201)TlCl/(123)I-BMIPP SPECT was performed in 73 patients within approximately 1 week of initial acute myocardial infarction (AMI) after percutaneous coronary intervention (PCI). We divided the left ventricular myocardium into 17 segments on each SPECT image and scored tracer accumulation in each segment with a five-point scoring system according to the American Heart Association criteria. Total severity scores were calculated by summing the scores for all 17 segments. The mismatch ratio between myocardial perfusion and metabolism was derived from the (201)TlCl and (123)I-BMIPP total severity scores: mismatch ratio=((123)I-BMIPP total severity score -(201)TlCl total severity score)/(123)I-BMIPP total severity score. Patients were classified according to Thrombolysis in Myocardial Infarction (TIMI) flow grade as having TIMI reflow grade 0-I (TIMI 0-I reflow group; n=11), II (TIMI II reflow group; n=17) and III (TIMI III reflow group; n=45). The TIMI III reflow group was subdivided into two groups with (201)TlCl total severity scores of < or =13 (TIMI III (A) reflow group; n=36) and > or =14 (TIMI III (B) reflow group; n=9), respectively. RESULTS: The mismatch ratios in the TIMI II (0.4 +/- 0.3) and TIMI III (0.4 +/- 0.2) reflow groups were significantly higher than that in the TIMI 0-1 reflow group (0.1 +/- 0.1, p<0.05). Although coronary angiography revealed TIMI III flow after reperfusion, the mismatch ratios in the TIMI III (B) reflow group (0.2 +/- 0.1) and in the TIMI 0-I reflow group (0.1 +/- 0.1) were significantly lower than that in the TIMI III (A) reflow group (0.4 +/- 0.2, p<0.01), reflecting noneffective recanalization (so called no-reflow phenomenon). CONCLUSION: (201)TlCl/(123)I-BMIPP dual-isotope myocardial SPECT reveals the biochemical degree of the no-reflow phenomenon, whereas coronary angiography shows recanalized vascular flow only. Dual-isotope myocardial SPECT might be useful for evaluating reperfusion therapy.

Adult↗

PubMed2005

Dual-isotope myocardial SPECT in patients with redefined myocardial infarction.

BACKGROUND: According to the redefinition of myocardial infarction (MI) by the ESC/ACC Committee, patients with unstable angina (UA) without significant elevation of creatine kinase (CK) but with elevation of troponin T should be diagnosed as MI. METHODS: One hundred and forty-six consecutive patients formerly diagnosed as UA, with peak CK levels 0.10 ng/ml). Dual SPECT findings were analyzed qualitatively and quantitatively in blinded manner. RESULTS: Forty-seven patients (32%) were redefined as MI and 99 patients (68%) were redefined as UA. On admission, there were small but statistically significant elevations in laboratory parameters such as white blood cell count, C-reactive protein, CK and CK-MB in the redefined MI group compared with the redefined UA group. The proportion of patients with perfusion and metabolic abnormalities was significantly higher in the redefined MI group (Tl defect 36% vs. 4%, odds ratio: 13.5, p<0.001; BMIPP defect 64% vs. 23%, odds ratio: 5.8, p<0.001). Semi-quantitative evaluation revealed that the total Tl and BMIPP scores were significantly higher in the redefined MI patients (p<0.001). CONCLUSIONS: In the redefined MI patients, perfusion and metabolic abnormalities occurred frequently and more extensively. However, Tl/BMIPP dual SPECT had limited ability to detect minor myocardial infarcts classified as redefined MI. A more sensitive stratification combined with troponin T directed assignment should be established to incorporate the ongoing minor infarcts which could not be assessed by serial dual-scintigraphic evaluations.

Aged↗

PubMed2005

Assessment of contractile response to dobutamine stress by means of ECG-gated myocardial SPECT: comparison with myocardial perfusion and fatty acid metabolism.

UNLABELLED: The present study assessed left ventricular performance during dobutamine stress measured using gated SPECT, and compared the results to myocardial perfusion and fatty acid metabolism. METHODS: Thirty-six patients with myocardial infarction given (99m)Tc-sestamibi or (99m)Tc-tetrofosmin were examined by gated SPECT at rest and during dobutamine stress (4-20 microg x kg(-1) x min(-1)). After acquiring data at the highest dose, 201TlCl was injected and dual-isotope SPECT was performed to assess myocardial ischemia. Thirty of 36 patients also underwent myocardial SPECT with 123I-BMIPP. Regional wall motion changes during dobutamine infusion were determined from the gated SPECT data and classified as: (1) Improvement, (2) Worsening, (3) No change, and (4) Biphasic response. For myocardial segments of each infarct area, stress 201Tl, rest (99m)Tc and (123)I-BMIPP uptakes were graded on a five-point scoring system of defects from 0 (normal) to 4 (grossly defective). RESULTS: Rest 99mTc defect score index (DSI) in No change area was significantly higher than that in Biphasic area. The ADSI (stress 201Tl - rest (99m)Tc) in Biphasic area was significantly higher than those in Improvement and No change areas. The deltaDSI (BMIPP - (99m)Tc) in Worsening area tended to be higher than that in No Change area. CONCLUSIONS: Regional contractile response to dobutamine stress analyzed by gated SPECT showed that the response in-myocardial infarct areas could be classified by rest and stress myocardial perfusion and BMIPP accumulation.

Coronary Vessels↗

PubMed2004

Three-dimensional display in staging hemodynamic brain ischemia for JET study: objective evaluation using SEE analysis and 3D-SSP display.

The Japanese EC-IC bypass trial (JET study) was established to evaluate the validity of MCA-STA anastomosis in intracranial arterial occlusive disease aiming at stroke prevention. This study must use an objective method to reliably estimate hemodynamic brain ischemia. We devised a method of objectively classifying the severity of hemodynamic ischemia using quantitatively analytical and display software, stereotactic extraction estimation for stereotactic brain coordinates and three-dimensional stereotactic surface projections (3D-SSP). We analyzed data from 16 patients registered in the JET study. Our method offers quantitative information and 3-dimensional displays of the CBF at rest and after Diamox challenge, vascular reserve and the severity of the hemodynamic brain ischemia. We compared the maximal projection counts with ROI data from tomographic images in the anterior commissure-posterior commissure plane. The maximal counts data correlated closely with the ROI data of rest and with Diamox SPECT images (both p < 0.0001). The slopes of the linear regression line were 1.15 and 1.12, respectively. The results of this study indicated that our method could simply and objectively evaluate the severity of impaired brain circulation. This procedure should support the evaluation of hemodynamic ischemia in the JET study although validation is required by several institutions using more study subjects.

Aged↗

PubMed2004

[Practice and future aspects of nuclear cardiology].

The field of nuclear cardiology has demonstrated sustained growth in recent years owing to its increasingly recognized value for clinical applications and patient management. Computer advances in this field have allowed the technology of ECG-gated SPECT to become a routine part of nuclear cardiology. In our laboratory, myocardial perfusion and left ventricular function during stress (bicycle exercise or dobutamine infusion) were analyzed in a single examination by means of gated SPECT. This procedure has the potential to provide comprehensive information with which to evaluate patients with ischemic heart disease. 123I-BMIPP is a branched-chain free fatty acid, and its distribution could provide useful information about metabolic function in patients with ischemic heart disease (including minor infarction). The solid-state gamma camera 2020 tc Imager is now commercially available and has been clinically applied. The lightweight and compact design of the camera allows mobility of the unit between departments and floors. This technique would be useful for assessing left ventricular function under emergency conditions. In this paper, the techniques of examinations are described, and potential assessments are addressed. We look forward to further advances in nuclear cardiology for the accurate diagnosis and management of patients with various cardiac diseases.

Electrocardiography↗

PubMed2003

Development of quantitative analysis method for stereotactic brain image: assessment of reduced accumulation in extent and severity using anatomical segmentation.

Through visual assessment by three-dimensional (3D) brain image analysis methods using stereotactic brain coordinates system, such as three-dimensional stereotactic surface projections and statistical parametric mapping, it is difficult to quantitatively assess anatomical information and the range of extent of an abnormal region. In this study, we devised a method to quantitatively assess local abnormal findings by segmenting a brain map according to anatomical structure. Through quantitative local abnormality assessment using this method, we studied the characteristics of distribution of reduced blood flow in cases with dementia of the Alzheimer type (DAT). Using twenty-five cases with DAT (mean age, 68.9 years old), all of whom were diagnosed as probable Alzheimer's disease based on NINCDS-ADRDA, we collected I-123 iodoamphetamine SPECT data. A 3D brain map using the 3D-SSP program was compared with the data of 20 cases in the control group, who age-matched the subject cases. To study local abnormalities on the 3D images, we divided the whole brain into 24 segments based on anatomical classification. We assessed the extent of an abnormal region in each segment (rate of the coordinates with a Z-value that exceeds the threshold value, in all coordinates within a segment), and severity (average Z-value of the coordinates with a Z-value that exceeds the threshold value). This method clarified orientation and expansion of reduced accumulation, through classifying stereotactic brain coordinates according to the anatomical structure. This method was considered useful for quantitatively grasping distribution abnormalities in the brain and changes in abnormality distribution.

Aged↗

PubMed2003

Assessment of left ventricular function using solid-state gamma camera equipped with a highly-sensitive collimator.

PURPOSE: The solid-state gamma camera 2020tc Imager (Digirad, CA) is now commercially available and has been clinically applied. The present study evaluates the feasibility of equilibrium radionuclide ventriculography (ERNV) within a 3 min period using this camera equipped with a highly sensitive collimator. MATERIALS AND METHODS: ERNV was performed from the best septal position (left anterior oblique view) in 20 patients with cardiac disease using a single detector anger-type gamma camera equipped with a low-energy, high-resolution collimator. Immediately thereafter, we performed a second ERNV using the solid-state gamma camera equipped with a highly sensitive collimator. Acquisition periods were 10 and 3 min, respectively. RESULTS: Significantly more counts were collected from over the left ventricle with the solid-state gamma camera over 3 min than those with the anger-type gamma camera over 10 min (817.1 +/- 387.8 k counts vs. 668.2 +/- 327.4 k counts, p < 0.01). The left ventricular ejection fraction obtained from ERNV data using the solid-state gamma camera correlated closely with those acquired by the anger-type gamma camera (r = 0.94, p < 0.0001, SEE = 5.93%). CONCLUSION: The results showed that the solid-state gamma camera could assess left ventricular function with excellent data collection efficiency and high reliability.

Equipment Failure Analysis↗

PubMed2002

Serial assessment of left ventricular performance at rest and during bicycle exercise by ECG-gated myocardial perfusion SPECT.

UNLABELLED: The present study evaluates left ventricular performance during exercise by ECG-gated myocardial perfusion SPECT with short-time data collection. METHODS: The study population consisted of 10 healthy volunteers (Group N) and 9 patients with ischemic heart disease (Group I). Seven patients in Group I had a history of prior myocardial infarction. Rest ECG-gated SPECT was performed 40 min after an injection of Tc-99m-tetrofosmin (555-740 MBq). After resting data acquisition, Group N underwent up to two 5-min stages of exercise (75 and 125 watts) on a detachable bicycle ergometer. The Group I patients all underwent symptom-limited, maximal testing on the ergometer. ECG-gated SPECT data were acquired from both groups for 3 min at rest and during the last 3 min of each exercise stage. RESULTS: Significant increases occurred in LVEF from rest to peak stress in both groups (from 55.4 +/- 5.8 to 66.6 +/- 4.1% in group N, p < 0.0001; from 49.0 +/- 12.8 to 56.7 +/- 13.8% in Group I, p < 0.001). The LVESV values significantly decreased to peak stress in Group N (from 49.9 +/- 13.1 to 37.8 +/- 10.0 ml, p < 0.0001), whereas LVEDV did not change (from 110.6 +/- 18.9 to 112.0 +/- 19.0 ml). In contrast, the LVESV values at rest and under peak stress were similar in Group I (from 52.6 +/- 23.9 to 51.7 +/- 31.4 ml) and LVEDV in Group I at peak exercise tended to increase (from 102.8 +/- 36.7 to 111.3 +/- 39.0 ml). The changes in LVESV from rest to peak stress were significantly different between Groups N and I (-12.1 +/- 6.3 vs. -0.9 +/- 11.6 ml, p < 0.02). CONCLUSION: ECG-gated SPECT with short-time data collection can assess left ventricular function during exercise and may offer useful information for evaluating patients with ischemic heart disease.

Adult↗

PubMed2002

Assessment of myocardial washout of Tc-99m-sestamibi in patients with chronic heart failure: comparison with normal control.

BACKGROUND: In contrast to 201TlCl, 99mTc-sestamibi shows very slow myocardial clearance after its initial myocardial uptake. In the present study, myocardial washout of 99mTc-sestamibi was calculated in patients with non-ischemic chronic heart failure (CHF) and compared with biventricular parameters obtained from first-pass and ECG-gated myocardial perfusion SPECT data. METHODS AND RESULTS: After administration of 99mTc-sestamibi, 25 patients with CHF and 8 normal controls (NC) were examined by ECG-gated myocardial perfusion SPECT and planar data acquisition in the early and delayed (interval of 3 hours) phase. Left ventricular ejection fraction (LVEF, %), peak filling rate (PFR, sec(-1)), end-diastolic volume (LVEDV, ml) and end-systolic volume (LVESV, ml) were automatically calculated from the ECG-gated SPECT data. Myocardial washout rates over 3 hours were calculated from the early and delayed planar images. Myocardial washout rates in the CHF group (39.6+/-5.2%) were significantly higher than those in the NC group (31.2+/-5.5%, p < 0.01). The myocardial washout rates for the 33 subjects showed significant correlations with LVEF (r = -0.61, p < 0.001), PFR (r = -0.47, p < 0.01), LVEDV (r = 0.45, p < 0.01) and LVESV (r = 0.48, p < 0.01). CONCLUSION: The myocardial washout rate of 99Tc-sestamibi is considered to be a novel marker for the diagnosis of myocardial damage in patients with chronic heart failure.

Adult↗

PubMed2002

Trial of autotransplantation of cryopreserved thyroid tissue for postoperative hypothyroidism in patients with Graves' disease.

BACKGROUND: Some patients with Graves' disease who select surgical therapy so they can discontinue antithyroid medication require lifelong levo-thyroxin (l-T4) replacement therapy because of irreversible postoperative hypothyroidism. The aim of this study was to enable the replacement of absent thyroid hormone through autotransplanted thyroid tissue that had been cryopreserved since the initial thyroid operation, and to release these patients from lifelong l-T4 administration. STUDY DESIGN: At the time of subtotal thyroidectomy for Graves' disease, the surgical specimen was partially cryopreserved at -196 degrees C until it was used for autotransplantation. After obtaining sufficient informed consent, four patients with postoperative hypothyroidism underwent autotransplantation of cryopreserved thyroid tissues. These patients required 50 to 150 microg/day of l-T4 at 1.8, 3.4, 3.5, and 2.8 years after operation. For the transplantation, 2.5 to 3.5 g of cryopreserved thyroid tissue was autotransplanted into the forearm muscle of each patient. RESULTS: In three of the patients, l-T4 administration could be discontinued and the clinical symptoms of hypothyroidism disappeared because of an improved serum thyroid-stimulating hormone level. Pathologic and immunohistochemical examinations of the thawed cryopreserved tissue demonstrated well-preserved thyroid structure and thyroglobulin-positive follicular cells and colloids, suggesting that the transplanted material was functional. In addition, 123I scintiscanning in patients 1 and 2 indicated an accumulation of radioactive iodine at the transplantation sites. One patient, who was able to discontinue l-T4 administration for 6 months, subsequently required l-T4 again because of recurrent hypothyroidism. BACKGROUND: Despite a few remaining uncertainties that must be resolved before this procedure is optimized, autotransplantation of cryopreserved thyroid tissue promises to be a useful therapeutic procedure for treating permanent postoperative hypothyroidism in patients with Graves' disease.

Adult↗

PubMed2002

[Multi-center study for the evaluation of clinical usefulness of attenuation and scatter correction on 201Tl myocardial SPECT].

The aim of this study was to evaluate the clinical usefulness of attenuation and scatter correction (AC, SC) on a 201Tl myocardial single-photon emission computed tomography (201Tl SPECT) as a multi-center trial. With a dual-detecter and a triple-detector SPECT systems with a 99mTc transmission source, simultaneous transmission/emission tomography (TCT/ECT) was performed on 38 patients with angiographically coronary heart disease (CHD) and 26 patients without evidence of CHD. Stress and delayed attenuation and scatter corrected images (SAC) and uncorrected images (NC) were reconstructed. On NC images of normal cases, influence of attenuation was greater in male than female. In comparison of 201Tl distribution between male and female, significant decrease in 201Tl activity was observed in the inferoposterior wall in male and that was observed in the anterobasal wall of the left myocardium in female. Such a difference in 201Tl distribution between male and female disappeared on SAC images. On the diagnostic performance for the identification of CHD, SAC images demonstrated improved specificity and accuracy values in the right coronary arterial territory (RCA) with visual analysis statistically. Sensitivity value in the RCA was also improved, but it was not statistically significant. Sensitivity value in the left circumflex arterial territory (LCX) increased without decrease in specificity value on SAC images. In the left anterior descending arterial territory (LAD), sensitivity value increased on SAC images. Although specificity value decreased on SAC images in LAD territory, it was not statistically significant. The difference in 201Tl distribution between male and female is improved in normal cases by attenuation and scatter correction on 201Tl myocardial SPECT. Diagnostic performance of CHD is also improved by attenuation and scatter correction, especially in territories of which specificity in assessing the absence of disease have been suboptimal. In conclusion, attenuation and scatter correction on 201Tl myocardial SPECT is considered to be clinically useful.

Adult↗

PubMed2002

[Clinical application of left ventricular volume and ejection fraction derived from gated SPECT data].

Left ventricular (LV) volume and ejection fraction (LVEF) derived from ECG-gated myocardial SPECT data are reproducible and objective. Those quantitative values, however, interacted according to varied factors such as a frame number per R-R interval, tracers, and processing-algorisms. A decrease of frame number per R-R interval yields underestimation of end-diastolic volume and overestimation of end-systolic volume, resulting in underestimation of LVEF. Thus, it is important to change a frame number per R-R interval by the examination purpose. A good correlation of LVEF is usually obtained, independent of a combination of tracer and processing-algorism. On the other hand, LV volume does not always show linearity between combinations of tracer and processing-algorism. An extraction of myocardial edge using QGS program is deteriorating in patients with small LV below 20 ml. It is crucial to assess LV functional values derived from ECG-gated SPECT data as clinical indices, taking the varied effects into consideration.

Algorithms↗

PubMed2002

[Assessment of biventricular function using gated blood pool SPECT with QBS software: comparison with planar radionuclide ventriculography].

UNLABELLED: Quantitative blood pool SPECT (QBS) is a new application for the quantitative assessment of biventricular function from gated blood pool SPECT (TMUGA). In this study, we compared biventricular function between planar radionuclide ventriculography and TMUGA. The reproducibility of measuring biventricular ejection fraction with QBS was also evaluated. MATERIALS AND METHODS: Thirty-five patients with cardiac disease were enrolled. Following intravenous bolus injection of 740 MBq of 99mTc human serum albumin-DTPA, first-pass radionuclide angiography (FP) and 25-gated interval planar multi-gated blood pool scintigraphy (PMUGA) were performed for the measurement of right ventricular ejection fraction (RVEF; %) and left ventricular ejection fraction (LVEF; %), respectively. Subsequently TMUGA data set was acquired with a dual-head gamma camera (16 gated intervals). Then, alternative LVEF and RVEF were measured using TMUGA with QBS. Regional left ventricular wall motion for both PMUGA and TMUGA were assessed with a 4-point scoring system respectively. RESULTS: Automatic biventricular border detection using QBS was feasible in 27 of 35 patients (70.7%). Measurements of TMUGA LVEF and RVEF were well reproducible, with interobserver correlation coefficient of 0.98 and 0.97, respectively. TMUGA LVEF showed excellent correlation with PMUGA LVEF (r = 0.98, SEE = 3.92%). The agreement of LV wall motion score between TMUGA and PMUGA was 88.1% (214 of 243 segments), with a kappa value of 0.82. On the other hand, RVEF determined by QBS had a 12.4% average overestimate compared to the same value obtained by FP. Moreover 95% confidential interval of TMUGA RVEF (-28.8 to +4.0%) was wider than that of TMUGA LVEF (-10.7 to +10.7%). CONCLUSION: TMUGA with QBS analysis provided accurate and reproducible data for global and regional left ventricular function. However, the results of RVEF with TMUGA were not satisfying as a replacement for those with FP and modifying the algorithm were needed to improve accuracy of quantification.

Adult↗

PubMed2002

[Cardiac pool scintigraphy using the solid-state Digirad 2020tc Imager--comparison with the conventional anger-type gamma camera using moving cardiac phantom].

UNLABELLED: Movable gamma camera, 2020tc Imager, was light miniaturized using Si photodiode as a semiconductor sensor instead of photomultiplier tubes. To validate performance of this new camera in cardiac pool scintigraphy, multigated equilibrium radionuclide ventriculography using the moving cardiac phantom was performed with 2020tc Imager and a conventional Agner-type gamma camera (PRISM 3000). METHOD: Both measured cardiac functional values were compared with the set-up ones for the phantom. Five-, 7.5-, and 10-minute-multigated data were acquired using both cameras under constant contractile condition. Constant 5-minute-multigated data acquisitions using 2020tc Imager were also carried out with varied contractile conditions. RESULTS: Measured ejection fraction (EF) derived from 2020tc Imager and an Anger-type camera were 68.5 +/- 0.6 and 70.3 +/- 1.4%, respectively. Both of these values were absolutely close to the set-up EF value of 70%. Both of end-diastolic volume and EF showed excellent correlation between set-up and measured values with the correlation coefficient of 0.97 and 0.99, respectively. CONCLUSION: This new movable camera could provide comparative cardiac functional values with an Anger-type camera and it can be useful to evaluate acute cardiac function in a coronary care unit.

Gamma Cameras↗

PubMedDate not supplied

Usefulness of gated myocardial perfusion SPECT imaging soon after exercise to identify postexercise stunning in patients with single-vessel coronary artery disease.

BACKGROUND: This study determines the value of gated single photon emission computed tomography (SPECT) imaging soon after exercise to identify patients with single-vessel disease and exercise-induced prolonged myocardial dysfunction (ie, postischemic stunning). METHODS AND RESULTS: We examined 19 normal individuals and 52 patients with single-vessel disease by use of 2-day technetium 99m tetrofosmin exercise/rest gated SPECT imaging. Sequential imaging was started 10, 30, and 50 minutes after exercise. The ejection fraction (EF) values were calculated with the Cedars-Sinai program. The participants were classified as follows: group A (normal individuals, n = 19), group B (individuals with coronary stenosis without Q-wave infarction, n = 18), group C (individuals with Q-wave infarction without myocardial ischemia, n = 15), and group D (individuals with Q-wave infarction and ischemia, n = 19). The post-stress EF values at 10 minutes (69.8% +/- 9.6% and 59.8% +/- 11.8%, respectively) were higher in groups A and C than those at 30 minutes (67.6% +/- 10.2% and 57.2% +/- 11.3%, respectively) ( P < .05) but were lower in group B (61.7% +/- 9.2%) than both the 30- and 50-minute values (64.2% +/- 9.5% and 64.6% +/- 9.4%, respectively; P < .05). The EF value did not significantly change in group D. CONCLUSIONS: Tc-99m gated SPECT imaging soon after exercise is superior to conventional late imaging to discriminate patients with single-vessel disease and postexercise stunning.

Adult↗

PubMedDate not supplied

Changes in distribution of splenic venous flow in the patients with cirrhotic liver.

BACKGROUND/AIMS: The aim of this study is to prove the hemodynamic change in distribution of splenic venous flow in the liver, especially in the cirrhotic liver, and to reveal and evaluate a participation of splenic venous flow in regeneration or enlargement of the hepatic lobe. METHODOLOGY: We studied the distribution of splenic venous flow in the liver of patients with normal liver (NL group, n=15), chronic hepatitis (CH group, n=8), and liver cirrhosis (LC group, n=13) with the technique of scintiphotosplenoportography after percutaneous intrasplenic injection of Technetium-99m-diethylenetriaminepentaacetic acid-galactosyl-human serum albumin. The index of splenic venous flow volume per unit hepatocytes (Vunit) was calculated in each hepatic lobe. To compare V value of the left lobe (VLunit) with that of the right lobe (VRunit), predominant index of the left lobe (L/R index) was defined as L/R index = VLunit/VRunit. RESULTS: The median (interquartile range) of L/R index of the LC group; 1.22 (1.06-1.70) was significantly higher than that of the NL group; 0.83 (0.66-0.92), p<0.001 and the CH group; 0.79 (0.69-0.92), p<0.001. CONCLUSIONS: L/R index reflects the change of portal hemodynamics in cirrhotic liver and is useful for discrimination between noncirrhosis and cirrhosis. These results suggest that in the liver exposed to continuous damages, splenic venous blood promotes liver fibrosis in the right lobe and eventually flows more into the left lobe with milder fibrosis.

Aged↗