Biomedical subjects

Kenya Murase

Publications and source records attributed to Kenya Murase.

At least 55 records · Page 3Linked to original sources

PubMed2004

Superimposed display of coronary artery on gated myocardial perfusion scintigraphy.

UNLABELLED: Fusion of images of vascular anatomy and of myocardial perfusion images might be helpful for understanding the relationship between ischemia and the responsible vessels. The aim of this study was to develop a simple means of superimposing the images obtained from coronary angiography and gated myocardial perfusion SPECT. METHODS: Right and left oblique views from conventional coronary angiography and left ventriculography (LVG) were stored as 512 x 512 x 8-bit digital datasets and combined. We reconstructed images from routine gated myocardial perfusion imaging (MPI) by using (99m)Tc-tetrofosmin to match the oblique positions between the image from MPI and combined angiographic images. We then generated a 3-dimensional (3D) surface map by using the quantitative gated SPECT (QGS)/quantitative perfusion SPECT (QPS) program. Both the combined angiographic images and the 3D surface map were rescaled and unified by registering the internal landmarks between the 2 images. After subtraction of the LVG image, the coronary angiogram and the 3D surface map were fused into 1 image. All processes were performed with the QGS/QPS program and commercially available graphic software. We applied this method to datasets from a cardiac phantom and from several patients with coronary artery disease. RESULTS: In the phantom study, our technique could obtain a 3D surface map in which the oblique angle was identified as that of radiography and could realize image registration and superimposition of radiography on scintigraphy. The preliminary results from the patients indicated that the markedly stenotic vessels showed good coincidence with the regional myocardial perfusion abnormalities on the unified images. In addition, these images could show the relationship between the coronary artery and regional wall motion in the gated mode. CONCLUSION: We developed a simple method of superimposing the image of the coronary artery tree on images from gated MPI. The technique yielded useful information about myocardial perfusion and function as well as the supplying coronary artery.

Adolescent↗

PubMed2003

Autoregressive moving average (ARMA) model applied to quantification of cerebral blood flow using dynamic susceptibility contrast-enhanced magnetic resonance imaging.

PURPOSE: To investigate the feasibility of the autoregressive moving average (ARMA) model for quantification of cerebral blood flow (CBF) with dynamic susceptibility contrast-enhanced magnetic resonance imaging (DSC-MRI) in comparison with deconvolution analysis based on singular value decomposition (DA-SVD). METHODS: Using computer simulations, we generated a time-dependent concentration of the contrast agent in the volume of interest (VOI) from the arterial input function (AIF) modeled as a gamma-variate function under various CBFs, cerebral blood volumes and signal-to-noise ratios (SNRs) for three different types of residue function (exponential, triangular, and box-shaped). We also considered the effects of delay and dispersion in AIF. The ARMA model and DA-SVD were used to estimate CBF values from the simulated concentration-time curves in the VOI and AIFs, and the estimated values were compared with the assumed values. RESULTS: We found that the CBF value estimated by the ARMA model was more sensitive to the SNR and the delay in AIF than that obtained by DA-SVD. Although the ARMA model considerably overestimated CBF at low SNRs, it estimated the CBF more accurately than did DA-SVD at high SNRs for the exponential or triangular residue function. CONCLUSION: We believe this study will contribute to an understanding of the usefulness and limitations of the ARMA model when applied to quantification of CBF with DSC-MRI.

Blood Flow Velocity↗

PubMed2003

Interobserver variability of cerebral blood flow measurements obtained using spectral analysis and technetium-99m labeled compounds.

Radionuclide angiography with technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) or technetium-99m ethyl cysteinate dimer (99mTc-ECD) enables the non-invasive estimation of absolute cerebral blood flow (CBF) to be determined by using spectral analysis (SA). We previously demonstrated the clinical use of SA; however, this method involves a few manual steps. The aim of this study was to evaluate the interobserver variability of CBF estimations made using SA and compare these results with those obtained by using graphical analysis (GA). In twenty patients with various brain diseases (27-74 years old), radionuclide angiography examinations were performed using 99mTc-labeled compounds (10 patients, 99mTc-HMPAO; 10 patients, 99mTc-ECD). Bilateral cerebral hemispheres were studied in all patients, and the brain perfusion index (BPI) values were estimated using SA and GA. The interobserver variability between two observers was then assessed. A good correlation between the BPI values assessed using both SA (BPI(S)) and GA (BPI(G)) was obtained. The correlation coefficient for BPI(S) (r = 0.987) was almost the same as that for BPI(G) (r = 0.982). The degree of interobserver variability was not affected by the measurement of elevated BPI values. Measurements carried out by two observers using both SA and GA exhibited a similar degree of interobserver variability. SA appears to have a satisfactory interobserver variability and may be more suitable for clinical applications.

Algorithms↗

PubMed2003

Spectral analysis: principle and clinical applications.

This review article describes the principle and clinical applications of spectral analysis. Spectral analysis provides a spectrum of the kinetic components which are involved in the regional uptake and partitioning of tracer from the blood to the tissue. This technique allows the tissue impulse response function to be derived with minimal modeling assumptions. Spectral analysis makes no a priori assumptions regarding the number of compartments or components required to describe the time course of tracer in the tissue. Spectral analysis can be applied to various dynamic data acquired by planar scintigraphy, single photon emission computed tomography (SPECT) or positron emission tomography (PET) as an alternative approach to compartment analysis. This analysis appears to be clinically useful, because it not only facilitates the interpretation of dynamic scintigraphic, SPECT or PET data, but also simplifies comparisons between regions and between subjects.

Algorithms↗

PubMed2003

Evaluation of the number of SPECT projections in the ordered subsets-expectation maximization image reconstruction method.

Filtered back projection (FBP) method, maximum likelihood-expectation maximization(ML-EM) method, and ordered subsets-expectation maximization (OS-EM) method are currently used for reconstruction of SPECT images in clinical studies. In the ML-EM method, images of good quality can be reconstructed even with a small sampling number of projection data, when compared with FBP. Shorter acquisition time and less radionuclide dose are preferable in the clinical setting if image quality is the same. In this study, we attempted to find optimal conditions for reconstruction of OS-EM images with commonly used sampling numbers of 30, 60 and 120 (step angles: 12 degrees, 6 degrees, and 3 degrees, respectively), with acquisition counts/projection of 30, 60, 120 and 240 each. We adjusted the pixel counts of reconstructed images to be constant, by setting combination of sampling number and counts/projection (120 sampling number for 30 counts/projection, 60 for 60, and 30 for 120). Among the 3 acquisition conditions, the small sampling number of 30 had large acquisition counts per direction, resulting in low signal to noise ratio. Under this condition, the resolution was slightly low, but the uniformity of images was high. The combination of OS-EM and smaller sampling projection number may be clinically useful with reduction of the examination time, which is also beneficial to reduce dead time for gamma-camera rotation.

Adult↗

PubMed2003

Quantification of the heterogeneity of cerebral blood flow in vascular dementia.

BACKGROUND: In vascular dementia (VaD), assessment of cerebral blood flow by single photon emission computed tomography (CBF SPECT) has been used to detect a patchy decrease of blood flow or a frontal reduction. In addition to reduced blood flow, the heterogeneous distribution of cerebral blood flow is often observed in VaD. However, no objective method to evaluate the heterogeneity has been established. In this study, we applied three-dimensional fractal analysis (3D-FA) to CBF SPECT images as a method for assessing the heterogeneity of the cerebral blood flow distribution in VaD. SUBJECTS AND METHODS: The subjects included 18 patients with a diagnosis of VaD (aged 69.7 +/- 8.3) based on neuropsychological testing and imaging findings and 18 age-matched controls (aged 66.9 +/- 10.3). CBF SPECT images were obtained with (99m)Tc-hexamethyl propyleneamine oxime. On the reconstructed images, we obtained a linear regression equation between the cut-off values (from 35 to 50 %) and the number of voxels with a radioactivity exceeding the cut-off value transformed into natural logarithms, and then calculated the fractal dimension from the slope of the regression line thus obtained. The Mini-Mental State Examination (MMSE) was used to evaluate cognitive function. RESULTS: The fractal dimensions were 1.084 +/- 0.153 and 0.853 +/- 0.062 (mean +/- SD) in the VaD and control groups, respectively. The fractal dimension was significantly greater in the VaD group than in the control group (p < 0.0001). A significant negative correlation was observed between the fractal dimension and the MMSE score in the VaD group (r = 0.871, p < 0.0001). CONCLUSIONS: Because the CBF SPECT images of VaD patients showed a higher fractal dimension, these images were quantitatively more heterogeneous than those of age-matched controls. In the VaD group, cognitive function was shown to decline as the fractal dimension increased and images became more heterogeneous.

Aged↗

PubMed2003

Quantitative mapping of cerebral deoxyhemoglobin content using MR imaging.

In this study, we present a magnetic resonance imaging (MRI) method for quantifying cerebral deoxyhemoglobin content that is based on a measurement of the reversible contribution (R'2) of the transverse relaxation rate under the assumption of a quantitative relationship between R'2 and deoxyhemoglobin content. A numerical simulation was performed assuming a specific pulse sequence conventionally employed for R'2 measurement. The results showed a near linear relationship between R'2 and deoxyhemoglobin content in the physiological range of oxygen extraction for almost all sized vessels, although a large diffusion effect for capillary sized vessels compromised the relationship. Concerning the methodology for R'2 measurement, a theoretical analysis showed that multiexponential transverse signal decay of brain parenchyma may result in a considerable underestimation or overestimation of R'2, if a conventional method is employed for R'2 quantification. A modified method for correcting the effect of multiexponential signal decay was employed for R'2 measurement of the brain in normal volunteers. The results showed a high level of agreement between the R'2 values measured in our study and those estimated from physiological parameters obtained using other modalities such as PET. In the context of BOLD contrast-based functional MRI, the method proposed provides a quantitative mapping of baseline cerebral deoxyhemoglobin content, which is the essential physiological parameter for calibrating the stimulation-induced BOLD signal change and mapping neuronal activity in a quantitative manner by functional MRI.

Adult↗

PubMed2003

[Analysis of the frequency components of CR portal images and application to multi-objective frequency processing].

The image contrast of portal images obtained using computed radiography (CR) is low for radiation therapy, and their noise level is high. In order to improve the image quality of CR portal images, we investigated the relationship between the frequency components of the bone edge and noise area. We used a personal computer, conventional flatbed scanner, and public-domain software (NIH Image). To analyze the frequency components of bone edges, we generated difference images from the original and unsharp mask images of various sizes. In addition, we analyzed the frequency components of noise, after changing the cut-off frequency on the power spectrum to process a low- and high-pass filter. We found that the frequency components of bone edges and noise areas ranged from 0.18 to 0.25 cycle/mm and 1.30 cycles/mm, respectively. We conclude that this process can remove noise from homogeneous areas and preserve bone edges using multi-objective frequency processing.

Bone and Bones↗

PubMed2003

Statistical image analysis of cerebral blood flow in vascular dementia with small-vessel disease.

UNLABELLED: Small-vessel disease with dementia, which is the most frequent type of vascular dementia (VaD), often shows a cerebral blood flow (CBF) distribution with no obvious focal abnormalities and is therefore difficult to evaluate objectively. In this study, we combined CBF SPECT with 3-dimensional fractal analysis (3D-FA) to quantitatively assess the heterogeneity of CBF distribution and with 3-dimensional stereotactic surface projections (3D-SSP) to evaluate the distribution of CBF. We then evaluated the clinical validity of these techniques for the imaging diagnosis of VaD. METHODS: The subjects consisted of 17 patients who were diagnosed as having VaD due to small-vessel disease (VaD group) on the basis of a full clinical examination, including history, neuropsychologic tests, neurologic examination, and neuroimaging methods, and 20 healthy volunteers (control group). CBF SPECT was performed with (99m)Tc-hexamethylpropyleneamine oxime, and the reconstructed images were subjected to image processing by 3D-FA and 3D-SSP. Based on the results, the fractal dimension (FD) was compared between the VaD and control groups, and the distribution pattern of CBF was examined in the VaD group. RESULTS: The mean FD values in the VaD group and the control group were 1.093 +/- 0.153 and 0.853 +/- 0.062 (mean +/- SD), respectively. The mean FD value in the VaD group was significantly higher than that in the control group (P < 0.0001). 3D-SSP analysis in the VaD group showed that there were 2 abnormal patterns: One was globally reduced blood flow in the whole cerebral cortex, and the other was a reduction mainly confined to the frontal region. CONCLUSION: CBF SPECT images showed higher mean FD values in the VaD group than in the control group, suggesting a difference in the heterogeneity of CBF. Image processing with 3D-SSP successfully revealed that reduced cortical blood flow could be divided into 2 patterns. Because image analysis techniques, such as 3D-FA and 3D-SSP, allowed the simple and objective evaluation of CBF in patients with VaD, these methods seem to be useful for detailed examination of the blood flow pattern detected by CBF SPECT in patients with VaD.

Aged↗

PubMed2003

Heterogeneity of cerebral blood flow in Alzheimer disease and vascular dementia.

BACKGROUND AND PURPOSE: Alzheimer disease (AD) and vascular dementia (VaD) are the two major diseases that cause dementia, and early diagnosis is important. Single photon emission CT (SPECT) of cerebral blood flow (CBF) is used for the early detection of dementia and as an auxiliary method for follow-up. AD shows reduced posterior blood flow and VaD manifests reduced anterior blood flow on CBF SPECT images. We examined the usefulness of 3D fractal analysis of CBF SPECT images to objectively quantify the heterogeneity of CBF in patients with AD and VaD. METHODS: Thirty-two patients with AD and 22 with VaD based on neuropsychologic tests and imaging findings, as well as 20 age-matched control subjects underwent technetium-99m hexamethyl propyleneamine oxime CBF SPECT. We then conducted statistical image processing by 3D fractal analysis on reconstructed data. Fractal dimension, an index of heterogeneity, was then calculated for the whole brain, as well as for the anterior and posterior regions of the brain. A higher fractal dimension indicates that the CBF SPECT image is uneven. The ratio of fractal dimension of the anterior region to fractal dimension of the posterior region (A/P ratio) was calculated. Heterogeneity of CBF was compared among the AD, VaD, and control groups. RESULTS: Fractal dimensions of the AD, VaD, and control groups were 1.072+/-0.179 (mean +/- SD), 1.005+/-0.156, and 0.806+/-0.06, respectively. A significant difference of fractal dimension was noted between the control group and the two types of dementia (P<.0001); however, no significant difference was noted between the AD and VaD groups. The A/P ratios of the AD and VaD groups were significantly different (0.952 and 1.163, respectively; P<.01). CONCLUSION: Analysis of CBF SPECT images quantitatively showed that the fractal dimension was significantly higher (indicating heterogeneity) in patients with AD and VaD when compared with age-matched control subjects. Comparison of the A/P ratio on CBF SPECT images between AD and VaD groups showed that the heterogeneity of CBF was posterior-dominant for AD and anterior-dominant for VaD. Thus, 3D fractal analysis enabled a simple and objective evaluation of the heterogeneity of CBF in patients with AD and VaD.

Aged↗

PubMed2002

Automatic determination of brain perfusion index for measurement of cerebral blood flow using spectral analysis and 99mTc-HMPAO.

Cerebral blood flow (CBF) can be non-invasively quantified using the brain perfusion index (BPI), determined from radionuclide angiographic data generated by technetium-99m hexamethylpropylene amine oxime ((99m)Tc-HMPAO). We previously reported the use of a spectral analysis (SA) method using (99m)Tc-HMPAO to calculate the BPI. In this report, we demonstrate an automatic method for determining the optimal BPI value and compare the optimal BPI values with the absolute CBF values measured using H(2)(15)O positron emission tomography (PET). Bilateral cerebral hemispheres of 11 patients with various brain diseases were examined using (99m)Tc-HMPAO. In the automatic SA procedure, the radioactivity curve for the aortic arch ( C (a)) was shifted by 0-10 s. The radioactivity curve for the brain ( C (b)) was estimated using the shifted C (a), and the error value between the actually measured and the estimated C (b) (Err) was calculated. When the Err was at a minimum, the BPI value was defined as optimal BPI. The difference in BPI from the optimal BPI was calculated as |BPI - optimal BPI| / optimal BPIx100 (%). In all participants, an H(2)(15)O PET examination was also performed, and the BPI values were compared with the absolute CBF values measured using H(2)(15)O PET (mCBF(PET)). The difference between BPI and the optimal BPI increased significantly from 4.87%+/-1.69% to 18.38%+/-3.93% (mean+/-SD) when the Err value increased. The optimal BPI value ( y) was well correlated with the mCBF(PET) value ( x) ( y=0.21 x-0.0075, r=0.800). Our results suggest that this automatic SA method provides an accurate estimate of BPI that can be used for the quantification of CBF using (99m)Tc-HMPAO SA.

Brain↗

PubMed2002

SPECT imaging with off-set detector system: comparison of sampling angles 2, 4 and 6 degrees.

PURPOSE: We evaluated an off set reconstruction method for single photon emission computed tomography (SPECT), and compared it with the conventional on set reconstruction method, using sampling angles of 2, 4, and 6 degrees. METHOD: A triple-detector system was used. In the off-set acquisition, sampling angles of the opposite detector were shifted 1/2 of the sampling angles of 2, 4, and 6 degrees. For example, when projection data were acquired every 6-degrees (sampling angle = 6 degrees), the projection angles were at 0 degrees, 6 degrees, 12 degrees, and 174 degrees with one detector, and 177 degrees, 183 degrees, 189 degrees, and 357 degrees with the other, opposite, detector. The conventional on set reconstruction images were compared with an off set reconstruction for a pool phantom of uniform concentration, a hot rods phantom, a myocardial phantom, and a human study. RESULTS: The off set reconstruction method was better at all three sampling angles. FWHM (mm) were 11.02 at off-set versus 11.17 at on-set (sampling angle 2 degrees), 11.13 at off-set versus 11.48 at on-set (sampling angle 4 degrees), and 11.24 at off-set versus 11.64 at on-set (sampling angle 6 degrees), respectively. In human myocardium SPECT, visualization of the interventricular septum and cardiac cavity was improved. CONCLUSION: Off set reconstruction by means of filtered back projection will be an efficient sampling mode, having a larger number of effective projection angles.

Adult↗

PubMed2002

Ischemic "memory image" in acute myocardial infarction of 123I-BMIPP after reperfusion therapy: a comparison with 99mTc-pyrophosphate and 201Tl dual-isotope SPECT.

Ischemic "memory image" is a phenomenon of 123I-15-(p-iodophenyl)-3-(R,S)-methylpentadecanoic acid (BMIPP) in which an area at risk of acute myocardial infarction (AMI), could be detected as a defect in a couple of weeks even after successful reperfusion therapy. The purpose of this study was to clarify the incidence of the ischemic "memory image" of 123I-BMIPP in patients with AMI by comparing 99mTc-PYP and 201Tl dual-isotope SPECT. Materials consisted of 14 patients with successfully reperfused AMI and 20 patients with old myocardial infarction (OMI). All AMI patients underwent PYP/Tl dual-isotope SPECT within 1 week after the onset of AMI, and BMIPP SPECT was performed within 1 week after the PYP/Tl dual-isotope SPECT. The extent and severity of the defect of BMIPP and Tl were visually scored into four grades: 0 = no defect to 3 = large or severe defect. These scores were compared. PYP positive AMI lesions were concordant with BMIPP defects (13/14). In AMI, both the extent and severity scores of BMIPP were higher than 201Tl (p < 0.001). Differences (BMIPP - Tl) of extent and severity scores were greater in AMI than in OMI (p < 0.001). In conclusion, the ischemic "memory image" obtained by means of the BMIPP is a common phenomenon (13/14) in AMI, and helpful in evaluating the area at risk.

Aged↗

PubMed2002

Measurement of heterogeneous distribution on Technegas SPECT images by three-dimensional fractal analysis.

This review article describes a method for quantifying heterogeneous distribution on Technegas (99mTc-carbon particle radioaerosol) SPECT images by three-dimensional fractal analysis (3D-FA). Technegas SPECT was performed to quantify the severity of pulmonary emphysema. We delineated the SPECT images by using five cut-offs (15, 20, 25, 30 and 35% of the maximal voxel radioactivity), and measured the total number of voxels in the areas surrounded by the contours obtained with each cut-off level. We calculated fractal dimensions from the relationship between the total number of voxels and the cut-off levels transformed into natural logarithms. The fractal dimension derived from 3D-FA is the relative and objective measurement, which can assess the heterogeneous distribution on Technegas SPECT images. The fractal dimension strongly correlate pulmonary function in patients with emphysema and well documented the overall and regional severity of emphysema.

Administration, Inhalation↗

PubMed2002

Attenuation correction of myocardial SPECT images with X-ray CT: effects of registration errors between X-ray CT and SPECT.

PURPOSE: Attenuation correction with an X-ray CT image is a new method to correct attenuation on SPECT imaging, but the effect of the registration errors between CT and SPECT images is unclear. In this study, we investigated the effects of the registration errors on myocardial SPECT, analyzing data from a phantom and a human volunteer. METHODS: Registerion (fusion) of the X-ray CT and SPECT images was done with standard packaged software in three dimensional fashion, by using linked transaxial, coronal and sagittal images. In the phantom study, an X-ray CT image was shifted 1 to 3 pixels on the x, y and z axes, and rotated 6 degrees clockwise. Attenuation correction maps generated from each misaligned X-ray CT image were used to reconstruct misaligned SPECT images of the phantom filled with 201Tl. In a human volunteer, X-ray CT was acquired in different conditions (during inspiration vs. expiration). CT values were transferred to an attenuation constant by using straight lines; an attenuation constant of 0/cm in the air (CT value = -1,000 HU) and that of 0.150/cm in water (CT value = 0 HU). For comparison, attenuation correction with transmission CT (TCT) data and an external gamma-ray source (99mTc) was also applied to reconstruct SPECT images. RESULTS: Simulated breast attenuation with a breast attachment, and inferior wall attenuation were properly corrected by means of the attenuation correction map generated from X-ray CT. As pixel shift increased, deviation of the SPECT images increased in misaligned images in the phantom study. In the human study, SPECT images were affected by the scan conditions of the X-ray CT. CONCLUSION: Attenuation correction of myocardial SPECT with an X-ray CT image is a simple and potentially beneficial method for clinical use, but accurate registration of the X-ray CT to SPECT image is essential for satisfactory attenuation correction.

Artifacts↗

PubMed2002

Survival prediction using artificial neural networks in patients with uterine cervical cancer treated by radiation therapy alone.

BACKGROUND: We evaluated the usefulness of artificial neural networks (ANNs) for survival prediction in patients with uterine cervical cancer treated by radiotherapy. METHODS: We used data from 134 patients with uterine cervical cancer treated by combined external and high-dose-rate remote afterloading intracavitary radiotherapy between 1978 and 1993. The ANNs were trained using the data from 67 randomly selected patients. Using the trained ANNs, we predicted the 5-year survival in the remaining 67 patients, and compared it with the known 5-year survival. The performance of the ANNs was evaluated using a receiver operating characteristic (ROC) curve and was compared using the area under the ROC curve (Az). RESULTS: When fundamental factors, such as age, performance status, hemoglobin, total protein, International Federation of Gynecology and Obstetrics (FIGO) stage, and histological type were used as inputs in the ANNs, Az was 0.5483 +/- 0.0145 (mean +/- SD). When the histological grading of radiation effect determined by periodic biopsy examination was used in addition to the fundamental factors, Az was highest (0.7782 +/- 0.0105). When the cytological grading of radiation effect by the periodic smear was used in addition to the fundamental factors, Az was 0.5523 +/- 0.0135, which was not significantly different from that when only the fundamental factors were used. CONCLUSION: ANNs allow us to evaluate the importance of prognostic factors, and make it possible to predict the survival of each patient. Using ANNs, the combination of histological grading of radiation effect determined by periodic biopsy examination, in addition to the fundamental factors, is the most effective for prediction of survival in patients with uterine cervical cancer.

Aged↗

PubMed2002

Measurement of localized ground-glass attenuation on thin-section computed tomography images: correlation with the progression of bronchioloalveolar carcinoma of the lung.

RATIONALE AND OBJECTIVE: This study was to measure localized ground-glass attenuation (GGA) in the peripheral lung on thin-section computed tomography (CT) and to assess any relationship between the attenuation and lesion. MATERIALS AND METHODS: Twenty-eight surgically resected tumors with localized GGA at thin-section CT were studied. The tumors were histologically diagnosed as 8 atypical adenomatous hyperplasia (AAH), 11 bronchioloalveolar carcinoma (BAC), and 9 BAC with fibrosis. We assumed three concentric circles, which were 0.8, 1.0, and 1.2 times the diameter of each tumor and measured the average CT values corresponding to inside each circle. We calculated a difference in CT value between 0.8 and 1.2 times the diameter of the tumor and defined as the contrast index. RESULTS: The contrast index for tumors with AAH, BAC, and BAC with fibrosis were 19.8 +/- 8.3, 42.5 +/- 16.0 (P < 0.05 vs. group with AAH), and 111.4 +/- 32.6 (P < 0.0001 vs. Group with BAC), respectively. The contrast index became greater in the stepwise progression from AAH to BAC and from BAC to BAC with fibrosis. CONCLUSION: The contrast index correlated histologic findings of the tumor growth in BAC. The contrast index may be a useful and objective measurement for determining surgical treatment for localized GGA in preoperative diagnosis.

Adenocarcinoma, Bronchiolo-Alveolar↗

PubMed2002

Assessment of acetazolamide reactivity in cerebral blood flow using spectral analysis and technetium-99m hexamethylpropylene amine oxime.

Cerebral blood flow (CBF) can be quantified noninvasively using the brain perfusion index (BPI), determined from radionuclide angiographic data generated with technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO). Previously, the BPI has been calculated using graphical analysis (GA); however, the GA method is greatly affected by the first-pass extraction fraction and retention fraction, which are not only variable, but lower in cases with an increased CBF, such as after the administration of acetazolamide. Thus, GA-calculated BPI values (BPIG) may not reflect the absolute CBF. The objective of this study was to use the spectral analysis of radionuclide angiographic data collected using 99mTc-HMPAO to examine changes in the BPI after the administration of acetazolamide. We studied the CBF of both cerebral hemispheres in six healthy male volunteers; the BPI was measured at rest and after the intravenous administration of 1 g of acetazolamide. In all participants, an H215O positron emission tomography (PET) examination was also performed, and the spectral analysis-calculated BPI values (BPIS) and BPIG values were compared with the actual CBF measured using H215O PET (mCBFPET). The BPIS was 1.070 +/- 0.051 (mean +/- SD) at rest and 1.497 +/- 0.098 after acetazolamide; the corresponding BPIG values were 0.646 +/- 0.073 and 0.721 +/- 0.107. The BPIS values were significantly correlated with the mCBFPET values, whereas the BPIG values were not. According to the BPIS values, the increase in BPI after the intravenous administration of acetazolamide was 40.1 +/- 8.4%, as opposed to an increase of only 11.3 +/- 6.5% according to the BPIG values. These results suggest that the spectral analysis of 99mTc-HMPAO-generated data yields a more reliable BPI than GA for the quantification of CBF after acetazolamide administration.

Acetazolamide↗