Regional cerebral glucose metabolism and blood flow in a patient with Marchiafava-Bignami disease.
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We report functional neuroimaging studies of a 54-year-old man with Marchiafava-Bignami disease (MBD). Glucose metabolic images obtained by [18F]-2-fluoro-2-deoxy-D-glucose positron emission tomography showed diffusely reduced whole brain metabolism and strongly decreased metabolism in the frontal and parietal lobes, orbital gyrus, and thalamus. Cerebral perfusion images showed a similarly decreased radioactivity pattern as the metabolic images. Functional neuroimages would be useful for understanding the pathophysiologic processes of MBD. (+info)
Increased ictal perfusion of the thalamus in paroxysmal kinesigenic dyskinesia.
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The ictal and interictal cerebral blood flow (CBF) were evaluated in a patient with right unilateral short lasting paroxysmal kinesigenic dyskinesia, by means of single photon emission computed tomography (SPECT). The patient was a 6 year old boy with no family history. During an attack, increased CBF was seen in the left thalamus. Subtraction of interictal CBF from ictal CBF disclosed a prominent increase in CBF in the left posterolateral part of the thalamus. This finding suggests that abnormal hyperactivity of thalamic neurons could be responsible for the pathophysiology of paroxysmal kinesigenic dyskinesia in this patient. (+info)
Quantitative measurement of regional cerebral blood flow with flow-sensitive alternating inversion recovery imaging: comparison with [iodine 123]-iodoamphetamin single photon emission CT.
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BACKGROUND AND PURPOSE: Flow-sensitive alternating inversion recovery (FAIR) MR imaging is a technique for depicting cerebral perfusion without contrast enhancement. Our purpose was to determine whether quantification at FAIR imaging can be used to assess regional cerebral blood flow (rCBF) in a manner similar to [iodine 123]-iodoamphetamin ((123)I-IMP) single photon emission CT (SPECT). METHODS: Nine patients with internal carotid or major cerebral arterial stenosis underwent (123)I-IMP SPECT and FAIR imaging (single section, different TIs, 1.5 T) at rest and after acetazolamide (Diamox) stress. FAIR and (123)I-IMP rCBF values were compared and correlated. Receiver operating characteristic analysis was conducted to detect hypoperfused segments on FAIR images. RESULTS: rCBF values of normally perfused segments were 41.53 and 51.91 mL/100 g/min for pre- and post-acetazolamide (123)I-IMP studies, respectively. Corresponding values for pre- and post-acetazolamide FAIR images, respectively, were 46.64 and 59.60 mL/100 g/min with a TI of 1200 milliseconds and 53.23 and 68.17 mL/100 g/min with a TI of 1400 milliseconds. (123)I-IMP and FAIR results were significantly correlated, with both pre- and post-acetazolamide images. Sensitivity (86%) in detecting hypoperfused segments was significantly higher with post-acetazolamide images (TI, 1400 milliseconds), and specificity (82-85%) and accuracy (80-82%) were higher with all pre- and post-acetazolamide images (all TIs). CONCLUSIONS: The significant correlation, high specificity and accuracy in detecting hypoperfused segments, similar increases in flow on both post-acetazolamide images, and absence of the need for contrast enhancement suggest that FAIR imaging, like nuclear medicine study, is complementary to routine MR imaging in the assessment of cerebral perfusion. (+info)
Detection of misery perfusion with split-dose 123I-iodoamphetamine single-photon emission computed tomography in patients with carotid occlusive diseases.
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BACKGROUND AND PURPOSE: Patients with carotid occlusive disease and stage 2 cerebral hemodynamic failure, characterized by an increased oxygen extraction fraction (OEF) as measured by positron emission tomography (PET) and otherwise known as misery perfusion, have a high risk of cerebral ischemia and subsequent stroke. In clinical practice, the detection of patients with misery perfusion through the use of widely available, noninvasive, and cost-effective modalities such as single-photon emission computed tomography (SPECT) is extremely important. METHODS: We evaluated the relationships between the regional hemodynamic status of cerebral circulation, measured with split-dose [123I] N-isopropyl-p-iodoamphetamine SPECT (123I-IMP SPECT) and an acetazolamide challenge, and hemodynamic parameters, including OEF measured with PET, in 27 patients with both unilateral and bilateral carotid occlusive diseases. RESULTS: A significant negative correlation was found between the SPECT-measured cerebrovascular reserve after acetazolamide administration and both the PET-measured OEF and cerebral blood volume. Neither the cerebrovascular reserve nor the cerebral blood flow index, when expressed as a SPECT-measured cerebrum-to-cerebellum ratio, was useful for detecting lesions with an elevated OEF. However, a combination of the cerebrovascular reserve and cerebral blood flow index showed high sensitivity, specificity, and positive predictive value for the detection of misery perfusion. CONCLUSIONS: Our study suggests that split-dose 123I-IMP SPECT with an acetazolamide challenge could be useful for screening patients with misery perfusion in carotid occlusive diseases. (+info)
Use of cerebrovascular reactivity in patients with symptomatic major cerebral artery occlusion to predict 5-year outcome: comparison of xenon-133 and iodine-123-IMP single-photon emission computed tomography.
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The aim of this prospective study was to investigate whether decreased cerebrovascular reactivity to acetazolamide, as determined by single-photon emission computed tomography (SPECT), is an independent predictor of the 5-year risk of subsequent stroke in patients with symptomatic major cerebral artery occlusion. Cerebrovascular reactivity to acetazolamide in the middle cerebral artery (MCA) territory ipsilateral to the occluded artery was determined on the basis of two different methodologies: cerebral blood flow (CBF) percent change obtained quantitatively from xenon-133 (133Xe) SPECT, and asymmetry index (AI) percent change obtained qualitatively from N-isopropyl-p-[123I]-iodoamphetamine (IMP) SPECT. Seventy patients with unilateral internal carotid artery or MCA occlusion were divided into two groups within each SPECT methodology (normal or decreased CBF percent change and AI percent change) and followed up for 5 years. Cumulative recurrence-free survival rates for patients with decreased CBF percent change were significantly lower than for those with normal CBF percent change (P = 0.0205). There was no significant difference in cumulative recurrence-free survival rates between patients with decreased AI percent change and those with normal AI percent change. Only decreased CBF percent change was a significant independent predictor of stroke recurrence (P = 0.0051). The present study demonstrated that decreased cerebrovascular reactivity to acetazolamide determined quantitatively by 133Xe SPECT is an independent predictor of the 5-year risk of subsequent stroke in patients with symptomatic major cerebral artery occlusion, and that the qualitative method using 123I-IMP SPECT is a poor predictor of the risk of subsequent stroke in this type of patient. (+info)
Decreased cerebral blood flow in renal transplant recipients.
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OBJECTIVE: We performed single-photon emission computed tomography (SPECT) to investigate the influence of renal transplantation on cerebral blood flow (CBF). PATIENTS AND METHODS: Fifteen renal transplant recipients and twelve normal subjects underwent cerebral SPECT with N-isopropyl-p -[123I] iodoamphetamine (123I-IMP). All transplant recipients received prednisolone and cyclosporine (CyA). Regional CBF (rCBF) was measured by defining regions of interest in the cerebral cortex, deep white matter, striatum, thalamus, and cerebellum. In transplant recipients, correlations to the mean overall cortical CBF were assessed using the interval from transplantation to measurement of SPECT, as well as the serum creatinine concentration. Moreover, to investigate the influence of CyA on CBF, the correlation between mean overall cortical CBF and CyA trough concentrations was assessed. RESULTS: In all regions, CBF in renal transplant recipients was significantly lower than in normal subjects. No significant correlation was seen between serum creatinine, interval from transplantation, or CyA trough concentrations and mean overall cortical CBF. CONCLUSION: Renal transplant recipients demonstrated a decrease in CBF, that can have an associated secondary pathology. Therefore, renal transplant recipients may benefit from post-operative MRI or CT. (+info)
Cortical blood flow during cerebral vasospasm after aneurysmal subarachnoid hemorrhage: three-dimensional N-isopropyl-p-[(123)I]iodoamphetamine single photon emission CT findings.
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BACKGROUND AND PURPOSE: The relationship between regional cerebral blood flow (rCBF) during cerebral vasospasm after subarachnoid hemorrhage (SAH) and angiographic vasospasm and the value of rCBF in predicting vasospasm and the prognosis are not fully delineated. Our aim was to investigate the changes in extent of vasospasm-induced decreased cortical rCBF on three-dimensional (3D) displays of single photon emission CT (SPECT) findings. The clinical usefulness of these assessments was analyzed. METHODS: In 58 cases of SAH, SPECT and digital subtraction angiography were performed on the same day, 5-9 days after SAH or within 24 hours after the onset of delayed ischemic neurologic deficit (DIND). Cerebral blood flow data were assessed by measuring the area of decreased cortical rCBF on 3D SPECT images. RESULTS: The area of decreased cortical rCBF on the 3D images was significantly increased in cases with DIND (P <.001), in cases with a large infarction due to vasospasm (P =.006), and in cases with a poor prognosis after vasospasm (P =.045). These increases were also related to the type of angiographic vasospasm; the greatest decrease in cortical rCBF occurred in the combined type (combination of the peripheral and proximal types) of vasospasm, followed by cases with the peripheral type, proximal type, and no angiographic vasospasm. In cases with DIND, patchy decreased cortical rCBF areas were seen before the onset of DIND. CONCLUSION: Combined-type vasospasm leads to reductions in CBF greater than those due to isolated peripheral or proximal vasospasm. Two-dimensional and mean-hemispheric CBF analyses are less sensitive for this change than is 3D SPECT. (+info)
Quantitative measurement of regional cerebrovascular reactivity to acetazolamide using 123I-N-isopropyl-p-iodoamphetamine autoradiography with SPECT: validation study using H2 15O with PET.
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A simplified technique using (123)I-N-isopropyl-p-iodoamphetamine ((123)I-IMP) autoradiography (ARG) with SPECT has been proposed recently for quantifying regional cerebral blood flow (rCBF). To validate the accuracy of (123)I-IMP-ARG for quantifying regional cerebrovascular reactivity (rCVR) to acetazolamide, we compared rCVR determined using (123)I-IMP-ARG with that determined using H(2)(15)O PET. METHODS: Thirty-nine patients with chronic stenoocclusive disease in a unilateral major cerebral artery underwent SPECT and PET studies before and after intravenous administration of acetazolamide. The rCBF images in the 4 conditions in each patient were calculated according to the ARG method. The same standard input function and the same distribution volume of 35 mL/mL were used in the calculation of rCBF images using the (123)I-IMP-ARG method at resting state and with acetazolamide challenge. One large cortical region of interest (ROI) for a unilateral middle cerebral artery territory was bilaterally determined on each standardized summed rCBF image. On the basis of the rCBF values in each ROI, rCVR to acetazolamide was calculated as follows: rCVR (%) = ([acetazolamide challenge rCBF - resting rCBF]/resting rCBF) x 100. RESULTS: Significant correlation was observed between rCVR values obtained using (123)I-IMP-ARG and H(2)(15)O PET methods in the 78 ROIs examined in the 39 patients (r = 0.820; P < 0.0001). When a rCVR lower than the mean - 2 SD of values obtained in healthy volunteers (18.4% for (123)I-IMP-ARG and 18.2% for H(2)(15)O PET) was defined as reduced, and when the H(2)(15)O PET method was assumed to represent the true determinant of rCVR, (123)I-IMP-ARG was 90% sensitive and 92% specific and displayed an 87% positive predictive value for detecting patients with reduced rCVR. CONCLUSION: These findings demonstrate that (123)I-IMP-ARG methods accurately quantify rCVR and can adequately define subgroups of patients with reduced rCVR. (+info)