[A case of Holmes tremor in which 123I-IMP SPECT and MRI findings suggest damage to the cerebellothalamic tract and the dentato-rubro-olivary pathway].

A 75-year-old woman was referred to our department in October 2022 with ataxia and involuntary movements of the right upper and lower limbs. She had experienced a left pontine hemorrhage in March 2021, which was managed conservatively. However, she had residual right-sided hemiplegia. In addition, she had cerebellar ataxia and a 2 |Hz resting tremor of the right upper and lower limbs, which was enhanced while maintaining posture and contemplation. Based on her history, and the findings of MRI and nuclear medicine imaging, we diagnosed the patient with Holmes tremor due to pontine hemorrhage. Holmes tremor is a rare movement disorder secondary to brainstem and thalamic lesions, characterized by a unilateral low-frequency tremor. In this case, 123I-IMP SPECT and MRI shows damage to the cerebellothalamic tract and dentaro-rubro-olivary pathway.

Memantine administration prevented chorea movement in Huntington's disease: a case report.

BACKGROUND: Huntington's disease is an autosomal dominant inherited disorder characterized by personality changes (such as irritability and restlessness) and psychotic symptoms (such as hallucinations and delusions). When the personality changes become noticeable, involuntary movements (chorea) also develop. The disease is caused by the CAG repeat expansion in the coding region of the HTT gene, and the diagnosis is based on the presence of this expansion. However, there is currently no effective treatment for the progression of Huntington's disease and its involuntary motor symptoms. Herein, we present a case in which memantine was effective in treating the chorea movements of Huntington's disease. CASE PRESENTATION: A 75-year-old Japanese woman presented to the hospital with involuntary movements of Huntington's disease that began when she was 73 years old. In a cerebral blood flow test (N-isopropyl-p-iodoamphetamine-single-photon emission computed tomography), decreased blood flow was observed in the precuneus (anterior wedge) and posterior cingulate gyrus. Usually, such areas of decreased blood flow are observed in patients with Alzheimer's-type dementia. So, we administered memantine for Alzheimer's-type dementia, and this treatment suppressed the involuntary movements of Huntington's disease, and the symptoms progressed slowly for 7 years after the onset of senility. In contrast, her brother died of complications of pneumonia during the course of Huntington's disease. CONCLUSIONS: We recorded changes in parameters such as the results of the N-isopropyl-p-iodoamphetamine-single-photon emission computed tomography and gait videos over 7 years. Treatment with memantine prevented the chorea movement and the progression of Huntington's disease. We believe this record will provide clinicians with valuable information in diagnosing and treating Huntington's disease.

Disappearance of hemichorea as the initial presentation of moyamoya disease after revascularization surgery regardless of residual hypoperfusion evaluated by quantitative N-isopropyl-p-123I-iodoamphetamine SPECT.

BACKGROUND AND IMPORTANCE: Although hypoperfusion of the basal ganglia or the frontal subcortical matter is suspected, the pathology of chorea in moyamoya disease remains unclarified. Herein, we report a case of moyamoya disease presenting with hemichorea and evaluate pre- and postoperative perfusion using single photon emission computed tomography with N-isopropyl-p-123I-iodoamphetamine (123I-IMP SPECT). CLINICAL PRESENTATION: An 18-year-old woman presented with choreic movement of her left limbs. Magnetic resonance imaging revealed an ivy sign, and 123I-IMP SPECT demonstrated decreased cerebral blood flow (CBF) and cerebral vascular reserve (CVR) values in the right hemisphere. The patient underwent direct and indirect revascularization surgery to improve cerebral hemodynamic impairment. The choreic movements entirely resolved immediately after surgery. Although CBF and CVR values in the ipsilateral hemisphere demonstrated by quantitative SPECT increased, these did not reach the normal values threshold. CONCLUSION: Choreic movement in moyamoya disease may be related to cerebral hemodynamic impairment. Further studies are required to elucidate its pathophysiological mechanisms.

Non-invasive regional cerebral blood flow quantification in the 123I-IMP autoradiography using artificial neural network.

PURPOSE: Regional cerebral blood flow (rCBF) quantification using 123I-N-isopropyl-p-iodoamphetamine (123I-IMP) requires an invasive, one-time-only arterial blood sampling for measuring the 123I-IMP arterial blood radioactivity concentration (Ca10). The purpose of this study was to estimate Ca10 by machine learning (ML) using artificial neural network (ANN) regression analysis and consequently calculating rCBF and cerebral vascular reactivity (CVR) in the dual-table autoradiography (DTARG) method. MATERIALS AND METHODS: This retrospective study included 294 patients who underwent rCBF measurements through the 123I-IMP DTARG. In the ML, the objective variable was defined by the measured Ca10, whereas the explanatory variables included 28 numeric parameters, such as patient characteristic values, total injection 123I-IMP radiation dose, cross-calibration factor, and the distribution of 123I-IMP count in the first scan. ML was performed with training (n = 235) and testing (n = 59) sets. Ca10 was estimated in testing set by our proposing model. Alternatively, the estimated Ca10 was also calculated via the conventional method. Subsequently, rCBF and CVR were calculated using estimated Ca10. Pearson's correlation coefficient (r-value) for the goodness of fit and the Bland-Altman analysis for assessing the potential agreement and bias were performed between the measured and estimated values. RESULTS: The r-value of Ca10 estimated by our proposed model was higher compared with the conventional method (0.81 and 0.66, respectively). In the Bland-Altman analysis, mean differences of 4.7 (95% limits of agreement (LoA): -18-27) and 4.1 (95% LoA: -35-43) were observed using proposed model and the conventional method, respectively. The r-values of rCBF at rest, rCBF after the acetazolamide challenge, and CVR calculated using the Ca10 estimated by our proposed model were 0.83, 0.80 and 0.95, respectively. CONCLUSION: Our proposed ANN-based model could accurately estimate the Ca10, rCBF, and CVR in DTARG. These results would enable non-invasive rCBF quantification in DTARG.

Generative adversarial network-created brain SPECTs of cerebral ischemia are indistinguishable to scans from real patients.

Deep convolutional generative adversarial networks (GAN) allow for creating images from existing databases. We applied a modified light-weight GAN (FastGAN) algorithm to cerebral blood flow SPECTs and aimed to evaluate whether this technology can generate created images close to real patients. Investigating three anatomical levels (cerebellum, CER; basal ganglia, BG; cortex, COR), 551 normal (248 CER, 174 BG, 129 COR) and 387 pathological brain SPECTs using N-isopropyl p-I-123-iodoamphetamine (123I-IMP) were included. For the latter scans, cerebral ischemic disease comprised 291 uni- (66 CER, 116 BG, 109 COR) and 96 bilateral defect patterns (44 BG, 52 COR). Our model was trained using a three-compartment anatomical input (dataset 'A'; including CER, BG, and COR), while for dataset 'B', only one anatomical region (COR) was included. Quantitative analyses provided mean counts (MC) and left/right (LR) hemisphere ratios, which were then compared to quantification from real images. For MC, 'B' was significantly different for normal and bilateral defect patterns (P < 0.0001, respectively), but not for unilateral ischemia (P = 0.77). Comparable results were recorded for LR, as normal and ischemia scans were significantly different relative to images acquired from real patients (P ≤ 0.01, respectively). Images provided by 'A', however, revealed comparable quantitative results when compared to real images, including normal (P = 0.8) and pathological scans (unilateral, P = 0.99; bilateral, P = 0.68) for MC. For LR, only uni- (P = 0.03), but not normal or bilateral defect scans (P ≥ 0.08) reached significance relative to images of real patients. With a minimum of only three anatomical compartments serving as stimuli, created cerebral SPECTs are indistinguishable to images from real patients. The applied FastGAN algorithm may allow to provide sufficient scan numbers in various clinical scenarios, e.g., for "data-hungry" deep learning technologies or in the context of orphan diseases.

Validity of the γ-Ray Evaluation with iodoamphetamine for Cerebral Blood Flow Assessment (REICA) method for quantification of cerebral blood flow including acetazolamide challenge test.

OBJECTIVE: The γ-Ray Evaluation with iodoamphetamine for Cerebral Blood Flow Assessment (REICA) is a new method for quantifying cerebral blood flow (CBF) using single-photon emission computed tomography (SPECT) and [123I]N-isopropyl-p-iodoamphetamine (123I-IMP). The present study aimed to validate the REICA method using data including acetazolamide challenge test. METHODS: The REICA and Graph-Plot (GP) methods were used to calculate mean CBF (mCBF) for 92 acquisitions (rest: 57, stress: 35) and cerebrovascular reactivity (CVR) in 33 patients. To obtain stress data, 15 mg/kg of acetazolamide was injected intravenously 10 min before the administration of 123I-IMP, and blood samples were collected under the same conditions as rest data. The reference standard was the Autoradiograph (ARG) method using arterial blood sampling, and the accuracy of the REICA method was analyzed by comparing it with each method. RESULTS: For mCBF, the correlation coefficients (r) were 0.792 for the REICA method and 0.636 for the GP method. For CVR, r values were 0.660 for the REICA method and 0.578 for the GP method. In both acquisitions, the REICA method had a stronger correlation with the ARG method than the GP method. For mCBF, there was a significant difference in the correlation coefficient between the two correlation coefficients (p < 0.01). CONCLUSIONS: The REICA method was more accurate than the GP method in quantifying CBF and closer to the ARG method. The REICA method, which is a noninvasive method of cerebral blood flow quantification using 123I-IMP, has great medical usefulness.

Nodal Peripheral T-cell Lymphoma with T Follicular Helper Phenotype Presenting as Chorea During Treatment: A Case Report and Literature Review.

A 72-year-old man presented with chorea while undergoing treatment for recurrence of nodal peripheral T-cell lymphoma with T follicular helper (TFH) phenotype. An examination by brain N-isopropyl-p-iodoamphetamine (123I-IMP)-single photon emission computed tomography (SPECT) revealed no abnormalities other than a decreased cerebral blood flow (CBF) in the left striatum. After four courses of salvage chemotherapy, his clinical symptoms and asymmetric cerebral perfusion improved, suggesting that the decreased CBF had caused chorea. The significance of brain SPECT has not been fully clarified in patients with chorea-associated malignant lymphoma, warranting further investigations. Brain SPECT is an alternative approach to identify abnormalities in such patients.

Assessment of cerebrovascular reserve with N-isopropyl-p-[123I]-iodoamphetamine time series analysis in patients with cerebrovascular disease.

ABSTRACT: Using N-isopropyl-p-[123I]-iodoamphetamine(123I-IMP) and single-photon emission computed tomography (SPECT), the relationship between cerebrovascular reserve and the 123I-IMP redistribution phenomenon was investigated.The 50 patients who matched the inclusion criteria were divided into control and ischemia groups, and the redistribution phenomenon was examined on resting images. The delayed images showed higher 123I-IMP accumulation in lesions in the middle cerebral artery(MCA) area and anterior cerebral artery(ACA) area, these watershed areas in the ischemia group than in the control group, confirming that the redistribution phenomenon exists with statistical significance (Wilcoxon test; control group vs ischemic group in the ACA area[P = .002], ACA-MCA watershed area(P = .014), MCA area(P = .025), and MCA-posterior cerebral artery(PCA) watershed area(P = .002). The patients were then divided into 4 types according to the Kuroda grading system, and the difference in the redistribution phenomenon was investigated between type III and the other 3 types.Compared with type I and type II, type III had a significantly lower rate of decrease in the radioisotope (RI) count, verifying the redistribution phenomenon (Student t test: type I vs type III in the ACA area(P = .008), ACA-MCA watershed area(P = .009), MCA area(P < .001), and MCA-PCA watershed area(P = .002); type II vs type III in the ACA area(P = .004), ACA-MCA watershed area(P = .2575), MCA area(P < .001), and MCA-PCA watershed area(P < .001). No significant difference between type III and type IV was observed in any area [(Student t test: type III vs type IV in the ACA area(P = .07), ACA-MCA watershed area(P = .38), MCA area(P = .05), and MCA-PCA watershed area(P = .24)].The redistribution phenomenon is associated with resting cerebral blood flow (CBF), but not necessarily with cerebral vascular reactivity (CVR).

Investigation of the new non-invasive semi-quantitative method of 123I-IMP pediatric cerebral perfusion SPECT.

In pediatric cases requiring quantification of cerebral blood flow (CBF) using 123I-N-isopropyl-p-iodoamphetamine (123I-IMP) single-photon emission computed tomography (SPECT), arterial blood sampling is sometimes impossible due to issues such as movement, crying, or body motion. If arterial blood sampling fails, quantitative diagnostic assessment becomes impossible despite radiation exposure. We devised a new easy non-invasive microsphere (e-NIMS) method using whole-body scan data. This method can be used in conjunction with autoradiography (ARG) and can provide supportive data for invasive CBF quantification. In this study, we examined the usefulness of e-NIMS for pediatric cerebral perfusion semi-quantitative SPECT and compared it with the invasive ARG. The e-NIMS estimates cardiac output (CO) using whole-body acquisition data after 123I-IMP injection and the body surface area from calculation formula. A whole-body scan was performed 5 minutes after the 123I-IMP injection and CO was estimated by region of interest (ROI) counts measured for the whole body, lungs, and brain using the whole-body anterior image. The mean CBF (mCBF) was compared with that acquired via ARG in 115 pediatric patients with suspected cerebrovascular disorders (age 0-15 years). Although the mCBF estimated by the e-NIMS indicated a slight deviation in the extremely low- or high-mCBF cases when compared with the values acquired using the invasive ARG, there was a good correlation between the two methods (r = 0.799; p < 0.001). There were no significant differences in the mCBF values based on physical features, such as patients' height, weight, and age. Our findings suggest that 123I-IMP brain perfusion SPECT with e-NIMS is the simplest semi-quantitative method that can provide supportive data for invasive CBF quantification. This method may be useful, especially in pediatric brain perfusion SPECT, when blood sampling or identifying pulmonary arteries for CO estimation using the graph plot method is difficult.

Assessment of SPECT-CT fusion images and semi-quantitative evaluation using SUV in 123I-IMP SPECT in patients with choroidal melanoma.

OBJECTIVES: The aim of this study was to assess the diagnostic ability of N-isopropyl-p-[I-123] iodoamphetamine (IMP) SPECT semi-quantitative evaluation based on the standardized uptake value (SUV) in patients with choroidal melanoma. The secondary aim was to investigate the 6-h IMP SPECT imaging in comparison with 24-h imaging. METHODS: Twenty-five patients (14 males and 11 females, mean age of 59.2-year-old) were analyzed in this retrospective study. Patients underwent 24-h IMP SPECT imaging with a gamma camera after intravenous injection of IMP. Twelve of 25 patients underwent 6-h SPECT imaging in addition to the 24-h imaging. All acquired SPECT images were fused with CT images using an image-analysis software. To assess the utility of semi-quantitative evaluation method, we introduced an image evaluation method using SUVmax comparing with conventional count-based uptake index (UI) evaluation of the lesion. Volumes-of-interest (VOIs) for SUVmax and regions-of-interest (ROIs) for UI were drawn referring to the SPECT-CT fusion image. Then the relationship between the 6- and 24-h images was examined both in SUV and UI evaluation. Furthermore, the relationship between the size category classification (SCC) by UICC/AJCC: 1-4 scales and each semi-quantitative value using SUVmax and UI was also assessed. RESULTS: SUVmax of the tumor was significantly higher than that of the normal side; 2.37 ± 0.88 and 1.77 ± 0.39 (P < 0.05) on 6-h image, 4.17 ± 1.73 and 2.04 ± 0.45 (P < 0.001) on 24-h image, respectively. UI of the tumor was also significantly higher than that of the normal side; 2.24 ± 0.67 and 1.53 ± 0.35 (P < 0.01) on 6-h image, 3.79 ± 1.24 and 1.67 ± 0.44 (P < 0.001) on 24-h image, respectively. There was a strong significant linear relationship in the evaluation with SUVmax between 6- and 24-h on the tumor side (R2 = 0.88, P < 0.0001), compared to that with Tumor-UI (R2 = 0.35, P < 0.05). In addition, SUVmax of the tumor clearly differentiated the SCC of the tumor category 4 from that of category 1, where SUVmax of the tumor for categories 1‒4 were 2.56 ± 0.59, 4.33 ± 1.92, 4.63 ± 1.45, and 5.73 ± 1.69, respectively (P < 0.05, for categories 1 and 4). CONCLUSIONS: The semi-quantitative evaluation by SUV of 123I-IMP SPECT images fused with CT images is useful for detecting choroidal melanoma. Moreover, 6-h imaging with SUV-based evaluation of 123I-IMP SPECT is promising compared to the conventional count-based UI evaluation method. Trial registration This study is registered in UMIN Clinical Trials Registry (UMIN-CTR) as UMIN study ID: UMIN000038174.

MM2-type sporadic Creutzfeldt-Jakob disease: new diagnostic criteria for MM2-cortical type.

OBJECTIVE: To clinically diagnose MM2-cortical (MM2C) and MM2-thalamic (MM2T)-type sporadic Creutzfeldt-Jakob disease (sCJD) at early stage with high sensitivity and specificity. METHODS: We reviewed the results of Creutzfeldt-Jakob disease Surveillance Study in Japan between April 1999 and September 2019, which included 254 patients with pathologically confirmed prion diseases, including 9 with MM2C-type sCJD (MM2C-sCJD) and 10 with MM2T-type sCJD (MM2T-sCJD), and 607 with non-prion diseases. RESULTS: According to the conventional criteria of sCJD, 4 of 9 patients with MM2C- and 7 of 10 patients with MM2T-sCJD could not be diagnosed with probable sCJD until their death. Compared with other types of sCJD, patients with MM2C-sCJD showed slower progression of the disease and cortical distribution of hyperintensity lesions on diffusion-weighted images of brain MRI. Patients with MM2T-sCJD also showed relatively slow progression and negative results for most of currently established investigations for diagnosis of sCJD. To clinically diagnose MM2C-sCJD, we propose the new criteria; diagnostic sensitivity and specificity to distinguish 'probable' MM2C-sCJD from other subtypes of sCJD, genetic or acquired prion diseases and non-prion disease controls were 77.8% and 98.5%, respectively. As for MM2T-sCJD, clinical and laboratory features are not characterised enough to develop its diagnostic criteria. CONCLUSIONS: MM2C-sCJD can be diagnosed at earlier stage using the new criteria with high sensitivity and specificity, although it is still difficult to diagnose MM2T-sCJD clinically.

Arterial transit artifacts observed by arterial spin labeling in Moyamoya disease.

OBJECTIVES: Arterial spin labeling (ASL) is a magnetic resonance imaging (MRI) technique used to assess cerebral perfusion. When tissue perfusion is impaired, such as in Moyamoya disease, a hyperintense band called the arterial transit artifact (ATA) may occur, which interferes with accurate measurements on ASL-MRI. In this study, we evaluated the correlation of ATAs with magnetic resonance angiography (MRA) and single-photon emission computed tomography (SPECT) imaging results in Moyamoya disease. The aim of our study was to elucidate the pathophysiology of ATAs and risk factors for high ATA scores. MATERIALS AND METHODS: This retrospective study included 28 patients (56 hemispheres) with Moyamoya disease treated at our institution. MRI, MRA, ASL perfusion, and N-isopropyl-[123I] b-iodoamphetamine (123I-IMP) SPECT were performed. In order to semi-quantitatively evaluate the degree of ATA, the ATA scores were measured according to the number of hyperintense signal bands in the cerebral cortex. The relationship between the ATA scores and clinical and radiological factors were analyzed. RESULTS: Regional cerebral blood flow (rCBF) determined with ASL weakly correlated with that determined by 123I-IMP SPECT (ρ=0.31, p=0.027). There was no significant association between the ATA scores and rCBF values determined with 123I-IMP SPECT (p=0.872, 0.745, 0.743 at PLD1000 (post-labeling delay), 1500, and 2000, respectively). However, there was a significant correlation between ATA scores and MRA scores (ρ=0.427 p=0.001; ρ=0.612 p=0.001; ρ=0.563 p=0.001 at PLD1000, 1500, and 2000, respectively). An analysis of patient background characteristics revealed a significantly higher incidence of high ATA scores in female patients, patients with high MRA scores, and patients with a distinguishable ivy sign. A multivariate analysis confirmed that female sex, high MRA score, and presence of an ivy sign were risk factors for high ATA scores. CONCLUSION: ATA scores were moderately correlated with MRA scores, and presence of an ivy sign was the most predictive factor for high ATA scores. A high ATA score determined using ASL in a patient with Moyamoya disease might suggest an advanced disease stage and a reduction in cerebrovascular reserve capacity.

The REICA method for quantification of cerebral blood flow is less affected by lung washout of [123I] IMP than the graph-plot method.

OBJECTIVE: The [Formula: see text]-Ray Evaluation with Iodoamphetamine for Cerebral blood flow Assessment (REICA) method is a new method for cerebral blood flow (CBF) quantification with SPECT and [123I] IMP, which does not require invasive arterial blood sampling, or the use of a regression formula. Moreover, it takes into consideration tracer retention, while the Graph-Plot (GP) method does not. This study aims to confirm the reliability of the REICA method in calculating CBF by accounting for pulmonary tracer retention artefact. METHODS: Data of 100 patients were retrospectively analyzed. Washout rate (WR) was defined as 1- (max count /min count) in the lungs. The bias due to WR was analyzed by dividing the data into high/low WR groups and a multiple regression analysis was also performed. RESULTS: The REICA method did not show significant bias according to the [Formula: see text] test ([Formula: see text]), while the GP method showed significant bias ([Formula: see text]). Both the REICA and GP methods showed significant correlation with autoradiography (ARG) method ([Formula: see text], [Formula: see text]) and WR ([Formula: see text], [Formula: see text]) when analyzed via multiple regression analysis with covariates of age and sex. CONCLUSIONS: The REICA method is a reliable method for CBF quantification, which is unaffected by tracer washout through the lungs unlike the GP method.

Symptomatic Cerebral Hyperperfusion After Cerebral Vasospasm Associated with Aneurysmal Subarachnoid Hemorrhage.

BACKGROUND: Cerebral hyperperfusion syndrome, which carries a potential risk of intracranial hemorrhage, is a rare and overlooked condition in the setting of subarachnoid hemorrhage (SAH). CASE DESCRIPTION: A 72-year-old female presenting with SAH underwent clipping of a ruptured aneurysm of the left middle cerebral artery. On post-SAH day 7, the patient exhibited motor aphasia due to cerebral vasospasm of the left middle cerebral artery. After recovery from symptomatic cerebral vasospasm, the patient became restless and suffered from right hemiparesis on post-SAH day 12. Initially, recurrence of cerebral vasospasm was suspected; however, cerebral blood flow measurement using single-photon emission computed tomography revealed apparently increased perfusion in the same territory of the left middle cerebral artery. Hypertensive therapy was not induced during the postoperative period. Her neurologic symptoms and signs of cerebral hyperperfusion gradually improved with intensive blood pressure lowering. CONCLUSIONS: This is the first report to describe postischemic cerebral hyperperfusion syndrome after symptomatic vasospasm detected using sequential single-photon emission computed tomography during the acute stage of SAH. Early diagnosis of this rare phenomenon is crucial given the necessity to lower blood pressure for preventing hemorrhagic complications, which is contrary to the usual management of patients with vasospasm.

Relationship between decreased cerebral blood flow and amnesia after microsurgery for anterior communicating artery aneurysm.

OBJECTIVE: Postoperative amnesia after surgery for anterior communicating artery aneurysm might be associated with the damage of the basal forebrain. Our purpose was to verify whether decreased regional cerebral blood flow (rCBF) in basal forebrain could be related to the degree of postoperative amnesia. METHODS: Regional voxel rCBF data analyzed using three-dimensional stereotactic surface projection on 123I-IMP-SPECT were compared between ten patients with postoperative amnesia and 13 normal subjects. The Severity (average Z score of the voxels with a Z score that exceeds a threshold value of 2) was calculated. The cerebral lobes with rCBF exhibiting Severity > 2 in all patients were identified. In these lobes, we then examined whether there was a gyrus exhibiting Severity that was negatively related to memory quotients (MQs). RESULTS: In the right subcallosal gyrus, there was a significant negative correlation between Severity and visual MQ (ρ= - 0.884, p = 0.0007) or general MQ (ρ =- 0.853, p = 0.0017). In the right anterior cingulate gyrus, there was a significant negative correlation between Severity and verbal MQ (ρ = - 0.769, p = 0.0092). In the right rectal gyrus, there was a significant negative correlation between Severity and general MQ (ρ = - 0.811, p = 0.0044). No significant correlations were found between Severity in other brain regions and verbal, visual, or general MQ. CONCLUSIONS: The decreased rCBF in the subcallosal gyrus included in the basal forebrain, anterior cingulate gyrus, and the rectal gyrus in the right hemisphere was related to postoperative amnesia.

Significance of Quantitative Cerebral Blood Flow Measurement in the Acute Stage after Revascularization Surgery for Adult Moyamoya Disease: Implication for the Pathological Threshold of Local Cerebral Hyperperfusion.

OBJECTIVE: Superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis is a standard surgical procedure for adult patients with moyamoya disease (MMD) and plays a role in preventing ischemic and/or hemorrhagic stroke. Cerebral hyperperfusion (CHP) syndrome is a potential complication of this procedure that can result in deleterious outcomes, such as delayed intracerebral hemorrhage, but the exact threshold of the pathological increase in postoperative cerebral blood flow (CBF) is unclear. Thus, we analyzed local CBF in the acute stage after revascularization surgery for adult MMD to predict CHP syndrome under modern perioperative management. MATERIALS AND METHODS: Fifty-nine consecutive adult MMD patients, aged 17-66 years old (mean 43.1), underwent STA-MCA anastomosis with indirect pial synangiosis for 65 affected hemispheres. All patients were perioperatively managed by strict blood pressure control (systolic pressure of 110-130 mm Hg) to prevent CHP syndrome. Local CBF at the site of anastomosis was quantitatively measured using the autoradiographic method by N-isopropyl-p-[123I] iodoamphetamine single-photon emission computed tomography 1 and 7 days after surgery, in addition to the preoperative CBF value at the corresponding area. We defined CHP phenomenon as a local CBF increase over 150% compared to the preoperative value. Then, we investigated the correlation between local hemodynamic change and the development of CHP syndrome. RESULTS: After 65 surgeries, 5 patients developed CHP syndrome, including 2 patients with delayed intracerebral hemorrhage (3.0%), 1 with symptomatic subarachnoid hemorrhage (1.5%), and 2 with focal neurological deterioration without hemorrhage. The CBF increase ratio was significantly higher in patients with CHP syndrome (270.7%) than in patients without CHP syndrome (135.2%, p = 0.003). Based on receiver operating characteristic analysis, the cutoff value for the pathological postoperative CBF increase ratio was 184.5% for CHP syndrome (sensitivity = 83.3%, specificity =  94.2%, area under the curve [AUC] value  =  0.825) and 241.3% for hemorrhagic CHP syndrome (sensitivity =  75.0%, specificity =  97.2%, AUC value  =  0.742). CONCLUSION: Quantitative measurement of the local CBF value in the early postoperative period provides essential information to predict CHP syndrome after STA-MCA anastomosis in patients with adult MMD. The pathological threshold of hemorrhagic CHP syndrome was as high as 241.3% by the local CBF increase ratio, but 2 patients (3.0%) developed delayed intracerebral hemorrhage in this series that were managed following the intensive perioperative management protocol. Thus, we recommend routine CBF measurement in the acute stage after direct revascularization surgery for adult MMD and satisfactory blood pressure control to avoid the deleterious effects of CHP.

Usefulness of the frontal lobe bottom and cerebellum tuber vermis line as an alternative clue to set the axial angle parallel to the AC-PC line in I-123 IMP SPECT imaging: a retrospective study.

We aimed to investigate whether the frontal lobe bottom and cerebellum tuber vermis (FLB-CTV) line on brain perfusion scintigraphy, using iodine-123 isopropyl iodoamphetamine single photon emission computed tomography (I-123 IMP SPECT) images, is useful to determine an axial angle parallel to the anterior commissure-posterior commissure (AC-PC) line. We measured the angular differences between the AC-PC line and the FLB-CTV line on midsagittal brain magnetic resonance imaging (MRI) scans of 100 patients. We also evaluated the angular differences of the FLB-CTV line between the IMP SPECT images and the computed tomography for attenuation correction (CTAC) images in the same 100 patients, using a reference line on the CTAC images. Furthermore, the inter-reader reproducibility of the FLB-CTV line measurements on IMP SPECT images of 50 patients between two readers was evaluated using the intra-class correlation coefficient (ICC) and 95% confidence interval (CI). The mean and standard deviation of the angular differences between the AC-PC and FLB-CTV lines on midsagittal brain MRI scans were - 1.24° and 1.14°, respectively. The mean and the standard deviation of the angular differences of the FLB-CTV line in the IMP SPECT and CTAC images were 0.87° and 0.48°, respectively. The ICC of the FLB-CTV line measurements on IMP SPECT images was 0.99 (95% CI 0.98-0.99). We demonstrated that the FLB-CTV line was almost parallel to the AC-PC line and could be reconstructed using IMP SPECT images. The FLB-CTV line can be used as additional evidence to set the axial angle parallel to the AC-PC line.

Measurement of cerebral vascular reserves with I-123 IMP SPECT without an arterial input function using the microsphere model and radiopharmaceutical dose calibration.

OBJECTIVES: Cerebral vascular reserve (CVR) is an important indicator for the management of and therapy for cerebral arterial occlusive disease (CAOD). Vasodilatory function is measured using the standard IMP-ARG method. The IMP autoradiography (IMP-ARG) method employed here uses a standardized input function, which was derived from 12 patients between 31 and 71 years of age. Because the population of elderly patients continues to increase in Japan, additional therapies are required to assess CVR in elderly patients with chronic cardiopulmonary disease or a history of smoking, in particular. Despite its popularity, alternatives to the IMP-ARG method are necessary. Here, we proposed the microsphere (MS) method without an input function. METHOD: Using this method and the IMP-ARG method, we measured the CVRs of 18 CAOD patients. RESULTS: The CVRs derived with these two methods were significantly and linearly correlated (r = 0.89, p < 0.01). CVRs categorized by severity were also found to correspond between the two methods (κ = 0.87). CONCLUSIONS: Thus, the method proposed here may serve as a supplemental to and be compatible with the IMP-ARG method for the assessment of CVR. Furthermore, the two methods, when used in conjunction, may result in less error than either would alone.

Anterior Choroidal Artery Infarction Evaluated with 123I-Imp Single-Photon Emission Computed Tomography and 7 Tesla Magnetic Resonance Imaging.

Anterior choroidal artery (AchA) infarction remains a challenging diagnosis although it was first described almost 100 years prior. N-isopropyl-p-[123I]-iodoamphetamine single-photon emission computed tomography (123I-IMP SPECT) and 7 Tesla magnetic resonance angiography (7T-MRA) are not routinely performed in cases of AchA infarction. Therefore, the application of 123I-IMP SPECT and 7T-MRA for AchA infarction has not been reported previously. A 67-year-old man presented with disturbed consciousness, gaze preference to the left, aphasia, right homonymous hemianopia, and right hemiparesis. Brain magnetic resonance imaging revealed infarction of the left posterior limb of the internal capsule. Left middle cerebral artery was clearly seen on MRA. However, 123I-IMP SPECT on day 13 showed cortical hypoperfusion which indicated thalamus involvement with neural deactivation. Additionally, 7T-MRA on day 15 revealed an intact left AchA suggesting reperfusion. The neurological deficits improved gradually after treatment and rehabilitation. This case demonstrates AchA infarction with cortical hypoperfusion associated with thalamus involvement, which was clarified by performing 123I-IMP SPECT and 7T-MRA. Perfusion analysis and evaluation of detailed vascular anatomy in stroke can be expected to elucidate pathological conditions.