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1.
Suppressing bladder artifacts in bone SPECT of the pelvis.
Allenbach, G, Prior, JO, Theumann, N, El-Hasnawy, N, Malterre, J, Delaloye, AB, Kamel, EM
Annals of nuclear medicine. 2007;(6):339-44
Abstract
OBJECTIVE Bladder-filling reconstruction artifacts have a detrimental effect on the image quality of pelvic bone single photon emission computed tomography (SPECT). Using a simple protocol consisting of forced diuresis coupled with intravenous (IV) hydration, this study was undertaken to obtain an artifact-free pelvic SPECT after discarding the residual urinary activity. METHODS Thirty patients were enrolled. In group I, pelvic SPECT was performed directly after normal void, whereas in group II, SPECT was preceded by IV injection of 0.5 mg/kg furosemide (maximum 40 mg) coupled with IV infusion of 500 cc of physiologic saline. Bladder-filling reconstruction artifacts were analyzed in group I patients, who had their images reconstructed using both filtered backprojection and iterative algorithms, both qualitatively and quantitatively by means of regions of interest (ROIs) drawn around the artifact-bearing bone areas as well as the corresponding contralateral sites. For group II patients, besides visual analysis, ROIs were placed over the sites corresponding to those of the group I patients. In every patient, total counts of each ROI were normalized to a reference ROI placed over the sacrum, and a ratio was created. RESULTS Using filtered backprojection, two forms of artifacts were identified in group I patients: first, a streak pattern that extended to the sacro-iliac joint in nine (60%) patients, the hip joint in five (33%), the superior pubic rami in four (27%), the sacrum in three (20%), and the ischium in one (6%); second, a count loss subtype which extended to the hip joints in nine (60%) patients. Corresponding values after iterative reconstruction were two (13%) for the sacro-iliac joint, three (20%) for the hip joint, one (6%) for the superior pubic ramus, and one (6%) for the sacrum. In five (33%) patients, residual count loss artifacts were still identifiable after iterative reconstruction. However in group II, no such effects were observed because the bladder activity reached near background level in 14 (93%) of 15 patients after three successive voids with a 3.5-fold decrease in the mean value of total bladder count in comparison with group I patients. A statistically significant difference was found between artifact- and non-artifact-harboring ROIs in group I whichever the method used for reconstruction, whereas the values of right and left hemi-pelvis ROIs/sacrum in group II were almost identical. CONCLUSIONS Forced diuresis coupled with parenteral hydration facilitates the acquisition of an artifact-free pelvic SPECT. Especially for clinical questions that focus on femoral heads and pubic bones, applying the aforementioned protocol may improve the diagnostic accuracy of pelvic bone SPECT.
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2.
Differential patterns of dopamine transporter loss in the basal ganglia of progressive supranuclear palsy and Parkinson's disease: analysis with [(123)I]IPT single photon emission computed tomography.
Im, JH, Chung, SJ, Kim, JS, Lee, MC
Journal of the neurological sciences. 2006;(1-2):103-9
Abstract
We evaluated the patterns of dopamine transporter loss in the striatum of ten controls, twenty patients with Parkinson's disease (PD), and nine with progressive supranuclear palsy (PSP) using (123)I-IPT single photon emission tomography (SPECT). Four ROIs in the striatum correspond to the head of caudate nucleus (ROI 1), a transitional region between head of caudate and putamen (ROI 2), anterior putamen (ROI 3), and posterior putamen (ROI 4). A striatal ratio of specific to nondisplaceable uptake (V3'') was calculated normalizing the activity of the ROIs to that of occipital cortex. V3'' values were significantly reduced in all ROIs of PD and PSP patients, compared with controls (p=0.001). V3'' value in ROI 2 was significantly lower in PSP group, compared with PD group (p=0.02). The percent reductions of striatal uptake in ROI 1, ROI 2, ROI 3 and ROI 4 were 56%, 53%, 64% and 78% in PD patients, whereas 75%, 72%, 75% and 77% in PSP patients, respectively. The reduction patterns of uptake were significantly different between PD and PSP groups (p=0.001). In PD patients, the percent reductions of (123)I-IPT uptake were significantly greater in ROI 3 and 4 compared with ROI 1 or 2, whereas those were similar in all ROIs of PSP patients. In addition, PD patients showed a significantly higher posterior putamen/caudate ratio of reduced (123)I-IPT uptake than the anterior putamen/caudate ratio (p=0.005). Our results implicate that (123)I-IPT SPECT is a relatively simple and reliable technique that may be useful in differentiating PD from PSP.
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3.
Effect of left ventricular function on diagnostic accuracy of FDG SPECT.
Matsunari, I, Bax, JJ, Blanksma, PK, Visser, FC, Kanayama, S, Yoneyama, T, Nekolla, SG, Tonami, N, Hisada, K
Annals of nuclear medicine. 2006;(1):51-6
Abstract
OBJECTIVES Fluorine-18 fluorodeoxyglucose (FDG) SPECT has emerged as an alternative to dedicated PET imaging. However, it remains uncertain whether FDG SPECT is an as accurate for viability assessment as FDG PET in patients with severely reduced left ventricular function. The aim of the study was to assess the diagnostic accuracy of FDG SPECT in a head-to-head comparison with FDG PET, and divide the patients according to the severity of left ventricular dysfunction. METHODS A total of 47 patients, with a history of myocardial infarction underwent FDG/perfusion (99mTc-sestamibi or 201Tl) SPECT as well as FDG/13N-ammonia PET. The patients were divided into 2 subgroups based on the left ventricular ejection fraction (LVEF) (35% cutoff). The left ventricular myocardium was divided into 13 segments, and each segment was classified as viable or scar using a semi-quantitative scoring system based on defect severity and the presence or absence of perfusion-FDG mismatch. RESULTS Of the 47 patients studied, 23 had LVEF < 35% (low LVEF group; mean 25 +/- 7%), whereas the remaining 24 had LVEF > or = 35% (high LVEF group; mean 47 +/- 6%). In the low LVEF group, 213 segments (71%) were dysfunctional, as compared to 102 (33%) in the high LVEF group. The agreement for detection of viability between PET and SPECT in the low LVEF group was 82% (kappa 0.63), which was not different from the agreement in the high LVEF group (85%, kappa 0.66, p = 0.42 versus low LVEF group). CONCLUSIONS The results indicate that FDG SPECT can be used for tissue viability assessment regardless of the severity of left ventricular dysfunction.
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4.
Usefulness of 99mTc-Technegas and 133Xe dynamic SPECT in ventilatory impairment.
Yokoe, K, Satoh, K, Yamamoto, Y, Nishiyama, Y, Asakura, H, Haba, R, Ohkawa, M
Nuclear medicine communications. 2006;(11):887-92
Abstract
AIM: To assess the usefulness of SPECT images using (99m)Tc-Technegas (Technegas) and (133)Xe dynamic single photon emission computed tomography (SPECT) (Xe gas) and high-resolution computed tomography (HRCT), as compared with pathological assessment in the detection of small-airway disease including pulmonary emphysema. METHODS Seventeen patients with lung cancer were studied. All patients who had undergone both Technegas and Xe gas and CT prior to surgery were examined. SPECT and HRCT results were compared with the results of pathological findings. Histopathological analysis was performed in an area distant from cancer in lobectomy specimens obtained at surgery. Pathological analysis was performed in relation to bronchitis, bronchiolitis, fibrosis of the alveoli and disruption in walls of the alveoli. RESULTS Pathological abnormality (mild-to-moderate abnormal change) was seen in all 17 cases. Three patients showed low attenuation areas on CT, and abnormal patterns in SPECT images. In 11 of 14 patients who showed normal findings on CT, SPECT imaging depicted abnormal findings. The remaining three patients had no abnormal findings on CT and both SPECT imaging. CONCLUSION Technegas and (133)Xe SPECT imaging is useful for evaluating small-airway disease including pulmonary emphysema. Furthermore, SPECT imaging is more useful than morphological HRCT imaging in the evaluation of small-airway disease including pulmonary emphysema.
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5.
Effects of tissue heterogeneity on cerebral vascular response to acetazolamide stress measured by an I-123-IMP autoradiographic method with single-photon emission computed tomography.
Ito, H, Shidahara, M, Inoue, K, Goto, R, Kinomura, S, Taki, Y, Okada, K, Kaneta, T, Sato, K, Sato, T, et al
Annals of nuclear medicine. 2005;(4):251-60
Abstract
OBJECTIVES Single-photon emission computed tomography (SPECT) with iodine-123 (123I)-labeled N-isopropyl-p-iodoamphetamine (IMP) is widely used in measuring the cerebral blood flow (CBF) response to acetazolamide stress for assessment of cerebral vascular reserve. To quantitate CBF by means of SPECT with IMP, an autoradiographic (ARG) method has been developed and is widely used. Because the relation between the brain counts on the SPECT scan and CBF is not linear in the ARG method, a mixture of gray and white matter in a pixel causes errors in the calculation of CBF. In the present study, errors in the calculation of CBF and vascular response to acetazolamide stress by the ARG method due to tissue heterogeneity were estimated by simulation study. Correction for effects of tissue heterogeneity in SPECT data was also attempted. METHODS Images of gray and white matter fraction were obtained by voxel-based morphometry analysis of magnetic resonance (MR) imaging data set. Ideal CBF images, which were generated from gray and white matter fraction images with assumed blood flow values for gray and white matter, were compared to CBF images generated by the ARG method. Correction for effects of tissue heterogeneity in SPECT data was performed with gray and white matter fraction data obtained from MR images. RESULTS Systematic underestimation of CBF due to tissue heterogeneity was observed in all brain regions. In the neocortical regions, underestimation by -21% to -16%, -26% to -20%, -31% to -24%, and -35% to -27% was observed for gray and white matter blood flow of 80 and 20, 100 and 25, 120 and 30, and 140 and 35 ml/100 ml/min, respectively. Vascular response was also systematically underestimated in most brain regions. Vascular responses in the neocortical regions ranged from 17% to 20%, from 31% to 37%, and from 42% to 52% when ideal vascular responses were 25%, 50%, and 75%, respectively. After correction for the effects of tissue heterogeneity, values of vascular response to acetazolamide stress ranged from 64% to 116% in the neocortical regions, whereas values obtained by the ARG method ranged from 48% to 52%. CONCLUSION Underestimation of the vascular response to acetazolamide stress due to tissue heterogeneity should be considered in the estimation of cerebral vascular reserve.
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6.
Validation of brain tumour imaging with p-[123I]iodo-L-phenylalanine and SPECT.
Hellwig, D, Ketter, R, Romeike, BF, Sell, N, Schaefer, A, Moringlane, JR, Kirsch, CM, Samnick, S
European journal of nuclear medicine and molecular imaging. 2005;(9):1041-9
Abstract
PURPOSE The aims of this prospective study were to validate single-photon emission computed tomography (SPECT) with p-[(123)I]iodo-L-phenylalanine (IPA) in brain tumours and to evaluate its potential for the characterisation of indeterminate brain lesions. METHODS In 45 patients with indeterminate brain lesions or suspected progression of glioma, amino acid uptake was studied using IPA-SPECT and compared with the final diagnosis established by biopsy or serial imaging. After image fusion of IPA-SPECT and magnetic resonance imaging, the presence of tumour was visually determined by two independent observers. IPA uptake was quantified as the ratio between maximum uptake in the suspicious lesion and mean uptake in unaffected brain. RESULTS Primary brain tumours were present in 35 cases (12 low-grade and 23 high-grade gliomas). Non-neoplastic brain lesions were confirmed in seven cases (three dysplasias, three inflammatory lesions, one lesion after effective therapy). Visual analysis showed a high concordance between the two observers (kappa=0.90, p<0.001), with sensitivity and specificity of 86% and 100% for the discrimination of primary brain tumours and non-neoplastic lesions. At 30 min p.i., IPA uptake in primary brain tumours was higher than that in non-neoplastic lesions (1.70+/-0.36 vs 1.14+/-0.18, p<0.05). Brain metastases showed no increased uptake (1.13+/-0.22, n=3). The persistent retention of IPA in low-grade gliomas without disruption of the blood-brain barrier was visualised up to 24 h p.i. Low-grade and high-grade gliomas showed equivalent IPA uptake (1.72+/-0.37 vs 1.67+/-0.36 at 30 min, p=0.745). CONCLUSION IPA shows long and specific retention in gliomas. IPA is a promising and safe radiopharmaceutical for the visualisation of gliomas and the characterisation of indeterminate brain lesions.
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7.
Baseline/postnitrate tetrofosmin SPECT for myocardial viability assessment in patients with postischemic severe left ventricular dysfunction: new evidence from MRI.
Giorgetti, A, Pingitore, A, Favilli, B, Kusch, A, Lombardi, M, Marzullo, P
Journal of nuclear medicine : official publication, Society of Nuclear Medicine. 2005;(8):1285-93
Abstract
UNLABELLED The aim of this study was to compare (99m)Tc-tetrofosmin SPECT with contrast-enhanced MRI (ceMRI), a new direct sign of myocardial fibrosis. METHODS We studied 21 patients (age, 60 +/- 11 y; 19 male) with previous myocardial infarction and severe left ventricular dysfunction (ceMRI EF, 29% +/- 6%). All patients underwent resting and postnitrate (intravenous isosorbide dinitrate) (99m)Tc-tetrofosmin gated SPECT as well as ceMRI. Scintigraphic analysis was performed using quantitative perfusion SPECT (QPS), providing the percentage radiotracer uptake and defect severity in a 20-segment model. Hyperenhancement was defined by the increase of ceMRI signal intensity 20 min after intravenous injection of gadolinium-diethylenetriaminepentaacetic acid and its regional extension as the percentage of the total segment area. RESULTS In ceMRI dysfunctional segments, the correlation between the extent of hyperenhancement and both (99m)Tc-tetrofosmin uptake and defect severity was significantly better after nitrate administration rather than at rest (P < 0.0001). Using a ceMRI cutoff below 40%, 102 of 196 (52%) segments were viable, whereas 94 (48%) segments were not viable. According to receiver-operating characteristic curve analysis, diagnostic accuracies were higher for postnitrate (99m)Tc-tetrofosmin uptake as well as perfusion defect severity than using resting data (0.84 vs. 0.71, P < 0.001; 0.89 vs. 0.76, P < 0.001, respectively). CONCLUSION After nitrate administration, (99m)Tc-tetrofosmin uptake and perfusion defect severity were closely related to ceMRI, demonstrating, in vivo, the existence of an inverse correlation between the transmural distribution of fibrosis and tracer delivery to the myocardium.
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8.
Brain perfusion differences between Parkinson's disease and multiple system atrophy with predominant parkinsonian features.
Matsui, H, Udaka, F, Miyoshi, T, Hara, N, Tamura, A, Oda, M, Kubori, T, Nishinaka, K, Kameyama, M
Parkinsonism & related disorders. 2005;(4):227-32
Abstract
BACKGROUND The patterns of regional cerebral blood flow in Parkinson's disease and multiple system atrophy remain inconsistent. OBJECTIVES To compare brain perfusion images of 123I-IMP SPECT between Parkinson's disease, multiple system atrophy with predominant parkinsonian features (MSA-P) and controls. METHODS Eighty-two patients with Parkinson's disease, 10 patients with MSA-P and 14 controls were studied. We performed 3D-SSP and volume of interest analysis using 123I-IMP scintigraphy. RESULTS Occipital perfusion of MSA-P increased compared to that of Parkinson's disease and perfusion in the cerebellum and primary sensorimotor cortex of Parkinson's disease increased compared to that of MSA-P. Perfusion in the putamen of MSA-P decreased compared to that of Parkinson's disease. CONCLUSION Our study demonstrated perfusion differences in 123I-IMP SPECT between the two diseases.
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9.
Assessment of myocardial viability using F-18 fluorodeoxyglucose/Tc-99m sestamibi dual-isotope simultaneous acquisition SPECT: comparison with Tl-201 stress-reinjection SPECT.
Wu, YW, Huang, PJ, Lee, CM, Ho, YL, Lin, LC, Wang, TD, Wang, SS, Chen, TH, Yen, RF
Journal of nuclear cardiology : official publication of the American Society of Nuclear Cardiology. 2005;(4):451-9
Abstract
BACKGROUND This study compared technetium 99m sestamibi/fluorine 18 fluorodeoxyglucose dual-isotope simultaneous acquisition (DISA) with stress-reinjection thallium 201 single photon emission computed tomography (SPECT) with regard to their ability to detect myocardial viability. METHODS AND RESULTS The study cohort consisted of 42 angiographically significant coronary artery disease patients with symptomatic congestive heart failure or regional wall motion abnormalities. In total, 398 dysfunctional segments in 40 patients were analyzed (2 patients were excluded because of poor-quality F-18 fluorodeoxyglucose images). Of the segments, 217 were diagnosed as viable and 144 as nonviable by both DISA and Tl-201, 33 were viable by DISA but nonviable by Tl-201, and 4 were viable by Tl-201 but nonviable by DISA. Most discrepancies were in the inferior wall. Of the 40 patients, 16 underwent revascularization. From the follow-up results for the 105 dysfunctional segments in these 16 patients, DISA viability appears to be a significant predicting factor (P = .014) for functional recovery after revascularization statistically whereas Tl-201 viability does not (P = .09). CONCLUSION Our study suggests that DISA viability provides more accurate prediction of postrevascularization functional recovery than Tl-201 viability. Given the small number of patients who underwent revascularization, the superiority of DISA over Tl-201 in detecting myocardial viability may be firmly established by further study on a large scale for patients with profound left ventricular dysfunction.
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10.
Assessment of regional lung functional impairment with co-registered respiratory-gated ventilation/perfusion SPET-CT images: initial experiences.
Suga, K, Yasuhiko, K, Zaki, M, Yamashita, T, Seto, A, Matsumoto, T, Matsunaga, N
European journal of nuclear medicine and molecular imaging. 2004;(2):240-9
Abstract
In this study, respiratory-gated ventilation and perfusion single-photon emission tomography (SPET) were used to define regional functional impairment and to obtain reliable co-registration with computed tomography (CT) images in various lung diseases. Using a triple-headed SPET unit and a physiological synchroniser, gated perfusion SPET was performed in a total of 78 patients with different pulmonary diseases, including metastatic nodules (n = 15); in 34 of these patients, it was performed in combination with gated technetium-99m Technegas SPET. Projection data were acquired using 60 stops over 120 degrees for each detector. Gated end-inspiration and ungated images were reconstructed from 1/8 data centered at peak inspiration for each regular respiratory cycle and full respiratory cycle data, respectively. Gated images were registered with tidal inspiration CT images using automated three-dimensional (3D) registration software. Registration mismatch was assessed by measuring 3D distance of the centroid of the nine selected round perfusion-defective nodules. Gated SPET images were completed within 29 min, and increased the number of visible ventilation and perfusion defects by 9.7% and 17.2%, respectively, as compared with ungated images; furthermore, lesion-to-normal lung contrast was significantly higher on gated SPET images. In the nine round perfusion-defective nodules, gated images yielded a significantly better SPET-CT match compared with ungated images (4.9 +/- 3.1 mm vs 19.0 +/- 9.1 mm, P<0.001). The co-registered SPET-CT images allowed accurate perception of the location and extent of each ventilation/perfusion defect on the underlying CT anatomy, and characterised the pathophysiology of the various diseases. By reducing respiratory motion effects and enhancing perfusion/ventilation defect clarity, gated SPET can provide reliable co-registered images with CT images to accurately characterise regional functional impairment in various lung diseases.