A Bayesian estimation method for cerebral blood flow measurement by area-detector CT perfusion imaging.

PURPOSE: Bayesian estimation with advanced noise reduction (BEANR) in CT perfusion (CTP) could deliver more reliable cerebral blood flow (CBF) measurements than the commonly used reformulated singular value decomposition (rSVD). We compared the efficacy of CBF measurement by CTP using BEANR and rSVD, evaluating both relative to N-isopropyl-p-[(123) I]- iodoamphetamine (123I-IMP) single-photon emission computed tomography (SPECT) as a reference standard, in patients with cerebrovascular disease. METHODS: Thirty-one patients with suspected cerebrovascular disease underwent both CTP on a 320 detector-row CT system and SPECT. We applied rSVD and BEANR in the ischemic and contralateral regions to create CBF maps and calculate CBF ratios from the ischemic side to the healthy contralateral side (CBF index). The analysis involved comparing the CBF index between CTP methods and SPECT using Pearson's correlation and limits of agreement determined with Bland-Altman analyses, before comparing the mean difference in the CBF index between each CTP method and SPECT using the Wilcoxon matched pairs signed-rank test. RESULTS: The CBF indices of BEANR and 123I-IMP SPECT were significantly and positively correlated (r = 0.55, p < 0.0001), but there was no significant correlation between the rSVD method and SPECT (r = 0.15, p > 0.05). BEANR produced smaller limits of agreement for CBF than rSVD. The mean difference in the CBF index between BEANR and SPECT differed significantly from that between rSVD and SPECT (p < 0.001). CONCLUSIONS: BEANR has a better potential utility for CBF measurement in CTP than rSVD compared to SPECT in patients with cerebrovascular disease.

Transient Global Cerebral Hypoperfusion as a Characteristic Cerebral Hemodynamic Pattern in the Acute Stage after Combined Revascularization Surgery for Pediatric Moyamoya Disease: N-Isopropyl-P-[123I] Iodoamphetamine Single-Photon Emission Computed Tomography Study.

INTRODUCTION: Surgical revascularization prevents cerebral ischemic attack by improving cerebral blood flow (CBF) in both adult and pediatric patients with moyamoya disease (MMD). Uneven hemodynamic changes, including local cerebral hyperperfusion and remote ischemia, can cause delayed intracerebral hemorrhage and perioperative infarctions in adult MMD patients, but the characteristic hemodynamic pattern among pediatric MMD patients after revascularization surgery is poorly understood. METHODS: This study included 16 consecutive pediatric MMD patients (age, 6-16 years; mean age, 11.3) undergoing superficial temporal artery-middle cerebral artery anastomosis combined with encephalo-duro-myo-synangiosis on 21 affected hemispheres. Perioperative management was conducted by aspirin administration and strict blood pressure control (110-130 mm Hg). We prospectively performed N-isopropyl-p-[123I] iodoamphetamine single-photon emission computed tomography on postoperative days (POD) 1 and 7 and analyzed the temporal changes in perioperative hemodynamics. RESULTS: Four patients (19.0%, 4/21) exhibited immediate CBF improvement from POD 1, which was classified as "immediate redistribution pattern." In contrast, 9 (42.9%, 9/21) demonstrated transient hemispheric global hypoperfusion at POD 1 and subsequent CBF improvement at POD 7, which was defined as "transient hypoperfusion pattern." Although 8 patients, including 4 with "transient hypoperfusion pattern" (44.4, 4/9), developed mild transient neurological deterioration in the acute stage, it resolved in all 21 patients, and there were no permanent neurological deficits. DISCUSSION/CONCLUSIONS: This study revealed that the "transient hypoperfusion pattern" after revascularization surgery is relatively common among pediatric MMD patients, and its outcome is favorable under strict perioperative management.

Relationship between cerebral hyperperfusion syndrome and the immediate change of cerebral blood flow after carotid artery stenting evaluated by single-photon emission computed tomography.

PURPOSE: Cerebral hyperperfusion syndrome (CHS) is a critical complication after carotid artery stenting (CAS). However, few CAS studies have evaluated immediate and temporary changes in ipsilateral cerebral blood flow (CBF) quantitatively. The study was performed to evaluate immediate changes in CBF after CAS and subsequent CBF changes in patients with cerebral hyperperfusion (HP) using 123I-IMP SPECT. METHODS: The subjects were 223 patients with chronic extracranial carotid artery stenosis who underwent CAS in our department between March 2010 and March 2020. Quantitative CBF and cerebrovascular reactivity to acetazolamide in the middle cerebral artery were assessed before CAS by 123I-IMP SPECT. CBF was also measured immediately after CAS by 123I-IMP SPECT. When HP was detected, CBF was measured again 3 and 7 days after CAS. RESULTS: The median (interquartile range) ipsilateral quantitative CBF change after CAS was - 0.1% (- 9.5-8.2%), and the upper value of the 95% CI of the quantitative CBF change was 48.2%. Thus, we defined HP after CAS as an increase in quantitative CBF of > 48.2% compared with the preoperative value. Of 223 patients, 5 (2.2%) had HP, and 4 of these patients (80%) developed CHS. In the CHS patients, HP was maintained for about 3 days and improved after about 7 days. CONCLUSION: An immediate CBF increase of > 48.2% after CAS may lead to development of CHS. In CHS after CAS, HP persisted for about 1 week and postoperative management may be required for at least 1 week.

Usefulness of dual isotope 123I-IMP and 201Tl SPECT for the diagnosis of primary central nervous system lymphoma and glioblastoma.

BACKGROUND: Preoperative differential diagnosis between primary central nervous system lymphoma (PCNSL) and glioblastoma (GBM) is important because these tumors require different surgical strategies. This study investigated the usefulness of dual isotope, iodine-123-labeled N-isopropyl-p-iodo-amphetamine (123I-IMP) and thallium-201 chloride single-photon emission computed tomography (201Tl SPECT) for the differential diagnosis. METHODS: Twenty-five PCNSL patients and 27 GBM patients who underwent dual isotope imaging, 123I-IMP and 201Tl SPECT, are included. Tumor-to-normal (T/N) ratio was calculated from the ratio of maximum tracer counts in the lesion to the mean counts in the contralateral cerebral cortex. The mean and minimum apparent diffusion coefficient values (ADCmean and ADCmin, respectively) on magnetic resonance imaging were also analyzed. RESULTS: Delayed phase 123I-IMP SPECT was the most useful imaging examination for the differentiation between PCNSL and GBM compared with early phase 123I-IMP SPECT, early and delayed phase 201Tl SPECT, ADCmean, and ADCmin. However, the median T/N ratios of PCNSL and GBM were 1.32 and 0.83, respectively, in the delayed phase 123I-IMP SPECT. On the other hand, the median T/N ratios of PCNSL and GBM were 3.10 and 2.34, respectively, in the delayed phase 201Tl SPECT, with excellent tumor detection. CONCLUSION: Delayed phase 123I-IMP SPECT could differentiate between PCNSL and GBM with high accuracy, but T/N ratio was low and tumor detection was poor. 201Tl SPECT was useful for estimation of the malignancy and localization of the tumors with high T/N ratio. Dual isotope 123I-IMP and 201Tl SPECT was useful for the preoperative diagnosis of PCNSL and GBM.

123I-IMP-SPECT in a patient with cerebral proliferative angiopathy: a case report.

Cerebral proliferative angiopathy (CPA) is a new clinical entity demonstrating a diffuse network of densely enhanced vascular abnormalities with intermingled normal brain parenchyma and is distinguishable from classical arteriovenous malformations by specific clinical and imaging markers. However, the pathophysiological nature of this disease is unclear, and there is no consensus on the treatment. We describe cerebral perfusion abnormalities in a patient with CPA by using N-isopropyl-p-[123I] iodoamphetamine single-photon emission computed tomography (123I-IMP-SPECT) and perfusion-weighted magnetic resonance imaging. The patient, a 13-year-old boy, had reversible focal neurological deficits unrelated to cerebral hemorrhage. 123I-IMP-SPECT at resting state showed preserved uptake within the vascular lesion, yet lower uptake in the area adjacent to the lesion. In addition, acetazolamide-stressed 123I-IMP-SPECT exhibited severely impaired cerebrovascular reactivity over the affected hemisphere, suggesting that his focal neurological deficits were related to the cerebral ischemia. The perfusion abnormalities on 123I-IMP-SPECT in a CPA patient have never been previously reported. The concept of vascular malformation-related hypoperfusion is discussed.

[Neuropsychological and regional cerebral blood flow of posterior parietal area features in patients with Parkinson's disease with mild cognitive impairment].

This study aimed to clarify associations between neuropsychological scales and regional cerebral blood flow (rCBF) of on |123I-IMP-SPECT in patients with Parkinson's disease with mild cognitive impairment (PD-MCI). Forty-two participants (mean age, 65.5 ± 8.9 years; mean disease duration, 11.1 ±5.7 years) were evaluated using the Wechsler Adult Intelligence Scale, third edition (WAIS-III), Wechsler Memory Scale, revised (WMS-R), Stroop test, Category word fluency, Auditory verbal learning test, Raven colored progressive matrices, Trail Making Test-B, and Clock drawing test. Participants were classified into PD-MCI and PD non-demented (PD-ND) using ten of these scales or its subtests. The rCBF of the posterior cingulate gyrus, precuneus, and parietal lobes was evaluated by |123I-IMP-SPECT using the easy Z-|score imaging system (eZIS analysis). Extent was the extent index of voxels showing z-score > 2, and Severity was mean z-score in those regions on eZIS analysis. Cingulate island sign score (CIScore) was the ratio of integrated z-scores of the posterior cingulate gyrus to those of the posterior cortex.Twenty-three participants were diagnosed with PD-MCI (55%). The rCBF indices were significantly increased in the PD-MCI group compared to the PD-ND group (Extent: P = 0.047; CIScore: P = 0.006). These indices were significantly correlated with WAIS-III Processing Speed (Extent: P = 0.041, R = -0.317; Severity: P = 0.047, R = -0.309), Stroop effect (Extent: P = 0.003, R = 0.443; Severity: P = 0.004, R = 0.437), WMS-R Visual memory (Extent: P = 0.019, R = -0.361; Severity: P = 0.014, R = -0.375), and Delayed memory score (Extent: P = 0.005, R = -0.423; Severity: P = 0.044, R = -0.312). The rCBF indices showed no correlations with the number of impaired cognitive domains. Collectively, decreased posterior parietal area rCBF and lower scores on selective neuropsychological scales might be helpful to detect a transition period from PD-MCI to PD-D.

"Semantic variant primary progressive aphasia" due to comorbidity of Lewy body disease and a previous cerebral venous infarction in the left anterior temporal lobe: A case report.

Primary progressive aphasia (PPA) is a neurological syndrome characterized by progressive language impairment. Various neurodegenerative disorders cause PPA. Dementia with Lewy bodies (DLB) is one known cause of PPA, and little is known about this association. Almost all published cases of PPA associated with DLB are the logopenic variant of PPA. Here, we describe the novel case of a patient with DLB presenting clinical features of the semantic variant PPA (svPPA). A 75-year-old woman was referred to our hospital with a 2-year history of progressive anomia and amnesia. Two months before admission, she had been experiencing visual hallucinations, and at the age of 60 years, she had venous infarction in the left temporal lobe, which she recovered from without any residual symptoms. Upon admission to our hospital, she displayed anomia, impaired single-word comprehension, and surface dyslexia with preserved repetition and speech production. These symptoms met the criteria for the diagnosis of svPPA. 123I-ioflupane single-photon emission computed tomography and 123I-meta-iodobenzylguanidine myocardial scintigraphy indicated DLB. Thus, she was administered donepezil, and this dramatically improved her symptoms. We hypothesize that the combination of DLB with the previous asymptomatic venous thrombosis in the left temporal lobe may have contributed to the "svPPA" in this patient. In conclusion, we show that PPA associated with DLB could be treated with donepezil, and we suggest that donepezil should be pursued as a treatment option for PPA.

Differences in cerebellar perfusion between Parkinson's disease and multiple system atrophy.

INTRODUCTION: Objective biomarkers are required for differential diagnosis of Parkinson's disease (PD), multiple system atrophy (MSA) and progressive supranuclear palsy (PSP). OBJECTIVE: We aimed to determine if cerebellar blood flow, measured using N-isopropyl-[123I] p-iodoamphetamine single photon emission computed tomography (123I -IMP-SPECT), was useful for differentiating between PD, MSA and PSP. METHODS: Twenty-four patients with PD, seventeen patients with MSA with predominant parkinsonian features (MSA-P), sixteenth patients with MSA with predominant cerebellar ataxia (MSA-C) and eight patients with PSP were enrolled. Twenty-seven normal controls' data were used for the calculation of z score. All patients underwent 123I -IMP-SPECT, and data were analyzed using a three-dimensional-stereotactic surface projection program. RESULTS: Cerebellar perfusion in MSA-P (MSA-P vs PD, P = .002; MSA-P vs PSP, P < .001) and MSA-C (MSA-C vs PD, P < .001; MSA-C vs PSP, P < .001) were significantly decreased compared with PD or PSP. There was no significant difference in perfusion between PD and PSP groups (P = .061). The area under the receiver operating characteristic curve for cerebellar perfusion between MSA-P and PD was 0.858. CONCLUSION: Our findings revealed that cerebellar perfusion by 123I-IMP-SPECT was useful for differentiating between PD and MSA-P.

A Case of Logopenic Variant of Primary Progressive Aphasia with Parkinsonism and Anosmia.

A 69-year-old right-handed woman developed difficulty naming objects and word-finding. The clinical features of language disorder and predominant atrophy on MRI and predominant hypoperfusion on 123I-IMP SPECT in the left temporo-parietal junction area were consistent with the diagnostic criteria for the logopenic variant of primary progressive aphasia (lvPPA). Neurological examination showed slight right-side rigidity and resting tremor (UPDRS-III: 4). 123I-FP-CIT SPECT showed presynaptic dopamine transporter reduction in the posterior putamina with left-side predominance. The odor-stick identification test for Japanese exhibited complete loss of the sense of smell (anosmia). These findings suggest that lvPPA may be accompanied by parkinsonism and anosmia.

[A case of chronic progressive neuro-Behcet's disease with cerebellar ataxia and bulbar palsy preceding mucocutaneo-ocular symptoms].

A 77-year-old man with a history of cigarette smoking had suffered from vertigo and depression repeatedly for twelve years. He gradually developed bradykinesia in the past half decade and fell down 3 times in the last half year. On admission, he presented with cerebellar ataxia and bulbar symptoms. Brain MRI showed atrophy in the cerebellum and brainstem. 123I-IMP SPECT showed hypoperfusion bilaterally in the cerebellum. Blood examinations showed various elevated inflammatory values and positive for HLA-B51. Cerebrospinal fluid (CSF) revealed aseptic meningitis and increased IL-6 levels. Therefore, we strongly suspected that he had chronic progressive neuro-Behcet's disease (CPNBD), clinically. Systemic mucocutaneous symptoms appeared 1 month after starting treatments. Pathological findings of his skin biopsy were consistent with Behcet's disease. It should be kept in mind that both positive HLA-B51 and increased CSF IL-6 levels have the possibility of containing important clues in the diagnosis of CPNBD.

Usefulness of the convexity apparent hyperperfusion sign in 123I-iodoamphetamine brain perfusion SPECT for the diagnosis of idiopathic normal pressure hydrocephalus.

OBJECTIVE: The gold standard for the diagnosis of idiopathic normal pressure hydrocephalus (iNPH) is the CSF removal test. For elderly patients, however, a less invasive diagnostic method is required. On MRI, high-convexity tightness was reported to be an important finding for the diagnosis of iNPH. On SPECT, patients with iNPH often show hyperperfusion of the high-convexity area. The authors tested 2 hypotheses regarding the SPECT finding: 1) it is relative hyperperfusion reflecting the increased gray matter density of the convexity, and 2) it is useful for the diagnosis of iNPH. The authors termed the SPECT finding the convexity apparent hyperperfusion (CAPPAH) sign. METHODS: Two clinical studies were conducted. In study 1, SPECT was performed for 20 patients suspected of having iNPH, and regional cerebral blood flow (rCBF) of the high-convexity area was examined using quantitative analysis. Clinical differences between patients with the CAPPAH sign (CAP) and those without it (NCAP) were also compared. In study 2, the CAPPAH sign was retrospectively assessed in 30 patients with iNPH and 19 healthy controls using SPECT images and 3D stereotactic surface projection. RESULTS: In study 1, rCBF of the high-convexity area of the CAP group was calculated as 35.2­43.7 ml/min/100 g, which is not higher than normal values of rCBF determined by SPECT. The NCAP group showed lower cognitive function and weaker responses to the removal of CSF than the CAP group. In study 2, the CAPPAH sign was positive only in patients with iNPH (24/30) and not in controls (sensitivity 80%, specificity 100%). The coincidence rate between tight high convexity on MRI and the CAPPAH sign was very high (28/30). CONCLUSIONS: Patients with iNPH showed hyperperfusion of the high-convexity area on SPECT; however, the presence of the CAPPAH sign did not indicate real hyperperfusion of rCBF in the high-convexity area. The authors speculated that patients with iNPH without the CAPPAH sign, despite showing tight high convexity on MRI, might have comorbidities such as Alzheimer's disease.

Fully automatic input function determination program for simple noninvasive (123)I-IMP microsphere cerebral blood flow quantification method.

We recently developed a simple noninvasive (123)I-IMP microsphere (SIMS) method using chest dynamic planar images and brain single photon emission computed tomography. The SIMS method is an automatic analysis method, except for the process of setting the region of interest (ROI) of the input function. If a fully automatic ROI setting algorithm can be developed to determine the input function for the SIMS method, repeatability and reproducibility of the analysis of regional cerebral blood flow (rCBF) of the SIMS method can be guaranteed. The purpose of this study is to develop a fully automatic input function determination program for the SIMS method and to confirm the clinical usefulness of this program. The automatic input function determination program consists of two ROI setting programs for the PA and lung regions, and it is developed using the image phase analysis of a chest RI angiogram. To confirm the clinical usefulness of this program, the rCBF in 34 patients measured using the automatic method were compared with the values obtained through the manual setting method. Input functions by the automatic and manual methods were approximately equal. A good correlation was observed between the rCBF values obtained by the automatic method and those obtained by the manual setting method (r=0.96, p<0.01). Further, the total time taken for the automatic SIMS analysis is 1-2min as compared to 20-30min for the current analysis, and therefore, this technique contributes to the improvement of the throughput of nuclear medical examinations.