Hypoxic viable tissue in human chronic cerebral ischemia because of unilateral major cerebral artery steno-occlusive disease.

BACKGROUND AND PURPOSE: Positron emission tomography (PET) with radiolabeled 2-nitroimidazoles directly detects hypoxic but viable tissue present in an acute ischemic area in the human brain. This study using PET with 1-(2-(18)F-fluoro-1-[hydroxymethyl]ethoxy) methyl-2-nitroimidazole ((18)F-FRP170) aimed to determine whether tissue with an abnormally elevated uptake of (18)F-FRP170 exists in human chronic cerebral ischemia because of unilateral atherosclerotic major cerebral artery steno-occlusive disease. METHODS: (18)F-FRP170 PET was performed, and cerebral blood flow and metabolism were assessed using (15)O-gas PET in 20 healthy subjects and 52 patients. A region of interest (ROI) was automatically placed in 3 segments of the middle cerebral artery territory in both cerebral hemispheres with a 3-dimensional stereotaxic ROI template using SPM2, and each PET value was determined in each ROI. The ratio of values in the affected versus contralateral hemispheres was calculated for the (18)F-FRP170 PET image. RESULTS: A significant correlation was observed between oxygen extraction fraction and (18)F-FRP170 ratios (ρ=0.509; P<0.0001) in a total of 156 ROIs in 52 patients. The specificity and positive-predictive value for a combination of an elevated oxygen extraction fraction and a moderately reduced cerebral oxygen metabolism for detection of an abnormally elevated (18)F-FRP170 ratio (19 ROIs: 12%) were significantly greater than those for the individual categories (elevated oxygen extraction fraction, moderately reduced cerebral oxygen metabolism, or reduced cerebral blood flow). CONCLUSIONS: Tissues with abnormally elevated uptake of (18)F-FRP170 exist in human chronic cerebral ischemia characterized by a combination of misery perfusion and moderately reduced oxygen metabolism because of unilateral atherosclerotic major cerebral artery steno-occlusive disease.

Delayed blink R1 latency in a patient with trigeminal neuralgia due to a contralateral vestibular schwannoma: An illustrative case.

Background: Although the blink reflex (BR) is effective in objectively evaluating trigeminal neuropathy, few studies have demonstrated its effect on trigeminal neuralgia (TN). The authors report a patient with TN due to contralateral vestibular schwannoma (VS) functionally diagnosed by delayed R1 latency of the BR. Case Description: A 36-year-old man presented with left-sided deafness and paroxysmal facial pain in the right V1-3 area. Magnetic resonance imaging (MRI) showed a solid cystic mass compressing the right pons and left brainstem at the left cerebellopontine angle. Although preoperative BR evoked by right supraorbital nerve stimulation-induced delayed ipsilateral R1 latency and normal ipsilateral and contralateral R2 responses, the BR latency evoked by left supraorbital nerve stimulation was normal, indicating deficits in the principal nucleus of the trigeminal nerve in the right pons. The symptoms of TN disappeared after the removal of the VS. Postoperative MRI showed subtotal removal of the tumor and sufficient decompression of the pons and cerebellopontine cistern. The R1 latency returned to normal 50 days after surgery. Conclusion: The perioperative BR test was not only useful for objective evaluation of the localization of trigeminal neuropathy but also correlated with the symptoms of TN.

Effect of combination therapy with the angiotensin receptor blocker losartan plus hydrochlorothiazide on brain perfusion in patients with both hypertension and cerebral hemodynamic impairment due to symptomatic chronic major cerebral artery steno-occlusive disease: a SPECT study.

BACKGROUND: While the combination of an angiotensin receptor blocker with thiazide diuretics produces a clinically beneficial reduction in blood pressure in patients who otherwise only partially respond to monotherapy with an angiotensin receptor blocker, blood pressure-lowering therapy with combination antihypertensive drug regimens in patients with cerebral hemodynamic impairment may adversely affect cerebral hemodynamics. The purpose of the present exploratory study was to determine whether blood pressure-lowering therapy with the combination of the angiotensin receptor blocker losartan plus hydrochlorothiazide (LPH) worsens brain perfusion in patients with both hypertension and cerebral hemodynamic impairment due to symptomatic chronic major cerebral artery steno-occlusive disease. METHODS: Patients with losartan-resistant hypertension and reduced cerebrovascular reactivity (CVR) to acetazolamide due to symptomatic chronic internal carotid artery (ICA) or middle cerebral artery (MCA) steno-occlusive disease were prospectively entered into the present study and received 50 mg/day of losartan plus 12.5 mg/day of hydrochlorothiazideat 14 weeks after the last ischemic event. Cerebral blood flow (CBF) and CVR were measured before and 12 weeks after initiating LPH using N-isopropyl-p-[(123)I]-iodoamphetamine single-photon emission computed tomography (SPECT). A region of interest (ROI) was automatically placed in the MCA territory on each SPECT image using a three-dimensional stereotactic ROI template. RESULTS: None of the 18 patients who participated in the study experienced any new neurological symptoms or adverse effects related to antihypertensive drugs. Systolic (p < 0.001) and diastolic (p < 0.001) blood pressures were significantly reduced after the administration of LPH, with average reductions of 11 mm Hg in systolic blood pressure and 10 mm Hg in diastolic blood pressure. While in the affected hemisphere CBF did not differ between measurements taken before and after the administration of LPH, CVR was significantly higher after the administration of LPH than before (p = 0.007) and was significantly improved in 5 of 18 patients. In the contralateral hemisphere, CBF and CVR did not differ between measurements taken before and after the administration of LPH. There were no patients who experienced a significant deterioration in CBF or CVR in the affected or contralateral hemisphere after the administration of LPH. CONCLUSIONS: Although the present study was exploratory and its results were preliminary due to the small sample size, the current data suggest that blood pressure-lowering therapy with LPH apparently does not result in worsening of cerebral hemodynamics in patients with both hypertension and cerebral hemodynamic impairment due to symptomatic chronic ICA or MCA steno-occlusive disease.

Camurati-Engelmann disease combined with transethmoidal meningoencephalocele: illustrative case.

BACKGROUND: Camurati-Engelmann disease (CED) is a rare disorder characterized by progressive cranial hyperostosis and diaphyseal sclerosis of the long bones. Chronic intracranial hypertension gradually occurs due to progressive cranial vault hyperostosis. OBSERVATIONS: A 57-year-old man who had been diagnosed with CED at 9 years old suddenly developed cerebrospinal fluid rhinorrhea. A bone defect of the right cribriform plate and protrusion of brain tissue from the right cribriform plate into the right nasal cavity were identified. The patient underwent endoscopic resection of the meningoencephalocele combined with the bath-plug procedure. After surgery, cerebrospinal fluid rhinorrhea disappeared. LESSONS: Chronic intracranial hypertension due to progressive cranial vault hyperostosis in CED may cause a bone defect and meningoencephalocele in the anterior skull base, resulting in cerebrospinal fluid rhinorrhea.

Primary Cranial Vault Lymphoma Extending between Subcutaneous Tissue and Brain Parenchyma without Skull Destruction after Mild Head Trauma: A Case Report and Literature Review.

Malignant lymphoma of the head rarely arises outside of the brain parenchyma as primary cranial vault lymphoma (PCVL). A case of PCVL that invaded from subcutaneous tissue into the brain, passing through the skull, and occurred after mild head trauma is reported along with a review of the literature. The patient was a 75-year-old man with decreased activity. One month before his visit to our hospital, he bruised the left frontal area of his head. Magnetic resonance imaging showed homogeneously enhanced tumors with contrast media in the subcutaneous tissue corresponding to the head impact area and the cerebral parenchyma, but no obvious abnormal findings in the skull. A biopsy with craniotomy was performed under general anesthesia. The pathological diagnosis was diffuse large B-cell lymphoma. On histological examination, tumor cells grew aggressively under the skin. Tumor cells invaded along the emissary vein into the external table without remarkable bone destruction and extended across the skull through the Haversian canals in the diploe. Tumor cells were found only at the perivascular areas in the dura mater and extended into the brain parenchyma. Considering the history of head trauma and the neuroimaging and histological findings, the PCVL in the present case arose primarily under the skin, passed though the skull and dura mater, and invaded along vessels and reached the brain.

Predicting the consistency of intracranial meningiomas using apparent diffusion coefficient maps derived from preoperative diffusion-weighted imaging.

OBJECTIVE: The consistency of meningiomas is a critical factor affecting the difficulty of resection, operative complications, and operative time. The apparent diffusion coefficient (ADC) is derived from diffusion-weighted imaging (DWI) and is calculated using two optimized b values. While the results of comparisons between the standard ADC and the consistency of meningiomas vary, the shifted ADC has been reported to be strongly correlated with liver stiffness. The purpose of the present prospective cohort study was to determine whether preoperative standard and shifted ADC maps predict the consistency of intracranial meningiomas. METHODS: Standard (b values 0 and 1000 sec/mm2) and shifted (b values 200 and 1500 sec/mm2) ADC maps were calculated using preoperative DWI in patients undergoing resection of intracranial meningiomas. Regions of interest (ROIs) were placed within the tumor on standard and shifted ADC maps and registered on the navigation system. Tumor tissue located at the registered ROI was resected through craniotomy, and its stiffness was measured using a durometer. The cutoff point lying closest to the upper left corner of a receiver operating characteristic (ROC) curve was determined for the detection of tumor stiffness such that an ultrasonic aspirator or scissors was always required for resection. Each tumor tissue sample with stiffness greater than or equal to or less than this cutoff point was defined as hard or soft tumor, respectively. RESULTS: For 76 ROIs obtained from 25 patients studied, significant negative correlations were observed between stiffness and the standard ADC (ρ = -0.465, p < 0.01) and the shifted ADC (ρ = -0.490, p < 0.01). The area under the ROC curve for detecting hard tumor (stiffness ≥ 20.8 kPa) did not differ between the standard ADC (0.820) and the shifted ADC (0.847) (p = 0.39). The positive predictive value (PPV) for the combination of a low standard ADC and a low shifted ADC for detecting hard tumor was 89%. The PPV for the combination of a high standard ADC and a high shifted ADC for detecting soft tumor (stiffness < 20.8 kPa) was 81%. CONCLUSIONS: A combination of standard and shifted ADC maps derived from preoperative DWI can be used to predict the consistency of intracranial meningiomas.

Microsurgical clipping for anterior communicating artery aneurysm associated with the accessory anterior cerebral artery via the pterional approach.

BACKGROUND: Accessory anterior cerebral artery (ACA), a type of median artery of anomalous triplicate ACA, is not rare, but aneurysms of the anterior communicating artery (ACoA) associated with accessory ACA can be a considerable challenge to treat surgically based on the morphological features of the ACoA complex. CASE DESCRIPTION: A 35-year-old man was admitted to our hospital with severe headache and subsequent loss of consciousness. Initial computed tomography (CT) showed typical findings of subarachnoid hemorrhage in the basal cistern and three-dimensional CT angiography revealed an ACoA aneurysm arising from the trifurcation of the accessory ACA, the branching point of the ACoA, and the right A1 or A2 segment of the ACA. The aneurysmal fundus projected superolaterally to the right, and was treated via a right-sided pterional approach. The aneurysm was behind the ipsilateral A2 segment of the ACA and the accessory ACA was hidden behind the aneurysm. The aneurysm was successfully obliterated with clipping using a straight fenestrated Yasargil titanium clip. Complete aneurysm occlusion and patency of both the A2 segment of the ACA and the accessory ACA were confirmed intraoperatively by indocyanine green angiography. CONCLUSION: In treating this aneurysm via the pterional approach, selection of approach side it is critical to preserve prevent the patency of the accessory ACA and to simultaneously perform aneurysm clipping without leaving a neck remnant. Selecting the optimal approach based on preoperative neuroimaging of which side will allow both these actions is important.

Fenestrated T-bar Clips in Surgical Management of Internal Carotid Artery Aneurysms: Technical Note.

BACKGROUND: Using a conventional right-angled fenestrated clip for an internal carotid artery (ICA) aneurysm is potentially disadvantageous because of the worse surgical visibility during and after clip application, especially in tight surgical fields. METHODS: We report a case of ruptured posteromedially projecting ICA aneurysm treated using a right-angled fenestrated T-bar clip (Yasargil titanium clip, Aesculap AG & Co, Tuttlingen, Germany). A 52-year-old woman was admitted to our hospital with severe headache. Three-dimensional computed tomography angiography showed a saccular aneurysm arising from the left, unusually short ICA, located proximal to the anterior choroidal artery. The right-angled fenestrated T-bar clip (blade length, 5 mm) was applied across the ICA, followed by reconstruction of the ICA wall with preservation of the anterior choroidal artery and simultaneous obliteration of the aneurysm. RESULTS: The key characteristic of the fenestrated T-bar clip is that the fenestrated portion of the clip is connected to the center of the blades. The tips of the blades on both sides are thus clearly visible during clip application. CONCLUSIONS: Application of the T-bar clip allows the surgeon to perform clip ligation of a posteromedially projecting ICA aneurysm while preserving the adjacent perforating artery.

Primary Central Nervous System Lymphoma Presenting as Growing Intracerebral Hemorrhage.

BACKGROUND: Hemorrhage at presentation in primary central nervous system (CNS) lymphoma is rare. We encountered a case of primary CNS lymphoma presenting as a growing intracerebral hemorrhage. CASE DESCRIPTION: An 80-year-old man presented with mild dysarthria. Computed tomography demonstrated a round, high-density mass with surrounding vasogenic edema in the left frontal lobe. Although the patient was placed on antihypertensive therapy for suspected subacute subcortical hemorrhage, neurologic symptoms gradually worsened. Computed tomography after 2 weeks revealed that the high-density lesion and surrounding edema had increased in size compared with previous images. The patient had been transferred to our hospital 14 days after admission to another institution. Magnetic resonance imaging demonstrated a mass lesion comprising hemorrhage of different phases in the left frontal lobe. Contrast-enhanced T1-weighted imaging demonstrated a mass lesion with heterogeneous enhancement in the left frontal lobe. The patient underwent craniotomy with gross total removal of the hemorrhagic lesion. The histopathologic diagnosis was diffuse large-cell non-Hodgkin lymphoma, and immunohistochemistry showed high immunoreactivity for vascular endothelial growth factor. CONCLUSION: Although exceedingly rare, primary central nervous system lymphoma can present as growing intracerebral hemorrhage due to repeated intratumoral hemorrhages. High expression of vascular endothelial growth factor and the mass effects of hemorrhage could be associated with the onset and growth of intracerebral hemorrhage. Early evaluation and meticulous observation are important to avoid progressive, life-threatening situations in such cases.

Apparent diffusion coefficient and arterial spin labeling perfusion of conventional chondrosarcoma in the parafalcine region: a case report.

Intracranial chondrosarcoma is a very rare malignant tumor of the central nervous system, and is difficult to preoperatively distinguish from other tumors using conventional imaging techniques. Here, we report the case of a 24-year-old woman who presented with mild headache due to chondrosarcoma in the frontal lobe. Preoperative conventional images showed findings typical of an oligodendroglial tumor. However, high apparent diffusion coefficient (ADC) value and extreme hypoperfusion on arterial spin labeling (ASL) were inconsistent with oligodendroglial tumor characteristics. The tumor was completely removed using a standard surgical procedure. Histologic diagnosis was a conventional (classic) chondrosarcoma. High ADC and hypoperfusion on ASL represented low cellularity and low vascularity within conventional chondrosarcoma, respectively. We discuss the utility of ADC and ASL for the preoperative diagnosis of conventional chondrosarcoma.

Subarachnoid Hemorrhage Due to Ruptured Intracranial Aneurysm Arising from a Vertebral Artery-Bihemispheric Posterior Inferior Cerebellar Artery Bifurcation.

Although the anatomy of the posterior inferior cerebellar artery (PICA) is highly variable, a solitary PICA supplying both hemispheres of the cerebellum is rare. A 76-year-old woman presented with severe headache and subsequent loss of consciousness and was admitted to our hospital. Initial computed tomography showed subarachnoid hemorrhage. Three-dimensional digital subtraction angiography revealed a saccular aneurysm arising from the right vertebral artery (VA)-PICA bifurcation. The PICA branching from the right VA was enlarged, tortuous, and crossed the midline to supply both cerebellar hemispheres. This right PICA was interpreted as a bihemispheric PICA. Recognizing this variant preoperatively could help prevent complications of surgery. Careful follow-up studies are necessary in cases with bihemispheric PICA to monitor for the development of aneurysm at the junction between the bihemispheric PICA and the VA or the distal portion of the bihemispheric PICA.

Subarachnoid hemorrhage due to ruptured intracranial aneurysm following posterior reversible encephalopathy syndrome.

Although posterior reversible encephalopathy syndrome (PRES) is rarely associated with subarachnoid hemorrhage, to our knowledge, rupture of a concomitant cerebral aneurysm following PRES has not been reported. We describe a patient with atypical PRES involving the brainstem, thalamus, and periventricular white matter without cortical or subcortical edema of the parietooccipital lobe on magnetic resonance imaging, with rupture of a concomitant cerebral aneurysm. Preexisting extremely high blood pressure may trigger atypical PRES, and failure to lower blood pressure may lead to a concomitant aneurysm rupture. In the future treatment of hypertensive urgency with a recurrence of symptoms and mean arterial blood pressure >150 mmHg, it is advisable to immediately hospitalize the patient for aggressive blood pressure management, especially if PRES is suspected based on clinical and radiological features.

High-uptake areas on positron emission tomography with the hypoxic radiotracer (18)F-FRP170 in glioblastomas include regions retaining proliferative activity under hypoxia.

OBJECTIVE: The aim was to evaluate the proliferative activity of high-uptake areas on positron emission tomography (PET) with the hypoxic cell radiotracer, 1-(2-[(18)F]fluoro-1-[hydroxymethyl]ethoxy)methyl-2-nitroimidazole (FRP170). METHODS: Thirteen patients with glioblastoma underwent FRP170 PET before tumor resection. During surgery, tumor specimens were stereotaxically obtained from regions corresponding to high (high-uptake areas, HUAs) and relatively low (low-uptake areas, LUAs) accumulation of FRP170. We compared immunohistochemical staining for Ki-67 and hypoxia-inducible factor (HIF)-1α between HUA and LUA. RESULTS: HIF-1α index was significantly higher in HUAs than in LUAs. In contrast, mean Ki-67 indices did not differ significantly between HUAs and LUAs. CONCLUSIONS: Findings for HIF-1α index clearly indicated that HUAs on FRP170 PET represented hypoxic regions in glioblastoma. However, findings of Ki-67 index suggest that HUAs on FRP170 PET include regions retaining proliferative activity regardless of tissue hypoxia.

Does preoperative measurement of cerebral blood flow with acetazolamide challenge in addition to preoperative measurement of cerebral blood flow at the resting state increase the predictive accuracy of development of cerebral hyperperfusion after carotid endarterectomy? Results from 500 cases with brain perfusion single-photon emission computed tomography study.

The purpose of the present study was to determine whether preoperative measurement of cerebral blood flow (CBF) with acetazolamide in addition to preoperative measurement of CBF at the resting state increases the predictive accuracy of development of cerebral hyperperfusion after carotid endarterectomy (CEA). CBF at the resting state and cerebrovascular reactivity (CVR) to acetazolamide were quantitatively assessed using N-isopropyl-p-[(123)I]-iodoamphetamine (IMP)-autoradiography method with single-photon emission computed tomography (SPECT) before CEA in 500 patients with ipsilateral internal carotid artery stenosis (≥ 70%). CBF measurement using (123)I-IMP SPECT was also performed immediately and 3 days after CEA. A region of interest (ROI) was automatically placed in the middle cerebral artery territory in the affected cerebral hemisphere using a three-dimensional stereotactic ROI template. Preoperative decreases in CBF at the resting state [95% confidence intervals (CIs), 0.855 to 0.967; P = 0.0023] and preoperative decreases in CVR to acetazolamide (95% CIs, 0.844 to 0.912; P < 0.0001) were significant independent predictors of post-CEA hyperperfusion. The area under the receiver operating characteristic curve for prediction of the development of post-CEA hyperperfusion was significantly greater for CVR to acetazolamide than for CBF at the resting state (difference between areas, 0.173; P < 0.0001). Sensitivity, specificity, and positive- and negative-predictive values for the prediction of the development of post-CEA hyperperfusion were significantly greater for CVR to acetazolamide than for CBF at the resting state (P < 0.05, respectively). The present study demonstrated that preoperative measurement of CBF with acetazolamide in addition to preoperative measurement of CBF at the resting state increases the predictive accuracy of the development of post-CEA hyperperfusion.

Post-carotid endarterectomy changes in cerebral glucose metabolism on (18)F-fluorodeoxyglucose positron emission tomography associated with postoperative improvement or impairment in cognitive function.

OBJECT: Cognitive function is often improved or impaired after carotid endarterectomy (CEA) for patients with cerebral hemodynamic impairment. Cerebral glucose metabolism measured using positron emission tomography (PET) with (18)F-fluorodeoxyglucose (FDG) correlates with cognitive function in patients with neurodegenerative diseases. The present study aimed to determine whether postoperative changes in cerebral glucose metabolism are associated with cognitive changes after CEA. METHODS: In patients who were scheduled to undergo CEA for ipsilateral internal carotid artery (ICA) stenosis (≥ 70% narrowing), cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) to acetazolamide were assessed preoperatively using brain perfusion single-photon emission computed tomography (SPECT). CBF measurement using SPECT was also performed immediately after CEA. For patients with reduced preoperative CVR to acetazolamide in the cerebral hemisphere ipsilateral to surgery, cerebral glucose metabolism was assessed using FDG-PET before surgery and 3 months after surgery and was analyzed using 3D stereotactic surface projection. Neuropsychological testing was also performed preoperatively and 3 months postoperatively. RESULTS: Twenty-two patients with reduced preoperative CVR to acetazolamide successfully underwent FDG-PET studies and neuropsychological testing before and after CEA. Seven, 9, and 6 patients were defined as showing improved, unchanged, and impaired postoperative cognition, respectively, based on the neuropsychological assessments. The cortical area with increased postoperative glucose metabolism was greater in patients with improved postoperative cognition than in those with unchanged (p < 0.001) or impaired (p < 0.001) postoperative cognition. The cortical area with decreased postoperative glucose metabolism was greater in patients with impaired postoperative cognition than in those with improved (p < 0.001) or unchanged (p < 0.001) postoperative cognition. All 7 patients with improved cognition exhibited postoperative hemispheric increases in glucose metabolism, while 5 of the 6 patients with impaired cognition exhibited postoperative hemispheric decreases in glucose metabolism. Brain perfusion SPECT revealed that the latter 6 patients experienced postoperative cerebral hyperperfusion, and 2 of the 6 patients exhibited cerebral hyperperfusion syndrome. The cortical area with decreased postoperative glucose metabolism in these 2 patients was greater than that in other patients. CONCLUSIONS: Postoperative changes in cerebral glucose metabolism, as measured using FDG-PET, are associated with cognitive improvement and impairment after CEA.

Intractable yawning associated with mature teratoma of the supramedial cerebellum.

Yawning occurs in various conditions such as hypoxia, epilepsy, and sleep disorders including sleep apnea. Intractable yawning associated with a brain tumor has been rarely reported. A 19-year-old woman presented with intractable yawning. Magnetic resonance imaging showed a tumor in the supramedial cerebellum that compressed the dorsal side of the midbrain and upper pons. After subtotal removal of the tumor, the yawning completely disappeared. Postoperative MRI showed resolution of compression of the brainstem. The tumor was histologically diagnosed as a mature teratoma. The present case suggested that the intractable yawning resulted from the tumor compressing the dorsal side of the junction between the midbrain and pons.

Combination of blood flow asymmetry in the cerebral and cerebellar hemispheres on brain perfusion SPECT predicts 5-year outcome in patients with symptomatic unilateral major cerebral artery occlusion.

BACKGROUND AND OBJECTIVE: Misery perfusion increases the risk of stroke recurrence in patients with symptomatic major cerebral artery occlusion. The ratio of brain perfusion contralateral-to-affected asymmetry in the cerebellar hemisphere to brain perfusion affected-to-contralateral asymmetry in the cerebral hemisphere (CblPR/CbrPR) indicates affected-to-contralateral asymmetry of oxygen extraction fraction (OEF) in the cerebral hemisphere. The purpose of the present study was to determine whether the CblPR/CbrPR on brain perfusion single-photon emission computed tomography (SPECT) predicts 5-year outcomes in patients with symptomatic unilateral occlusion of the middle cerebral artery (MCA) or internal carotid artery (ICA). METHODS: Brain perfusion was assessed using N-isopropyl-p-[123I]-iodoamphetamine (123I-IMP) SPECT in 70 patients. A region of interest (ROI) was manually placed in the bilateral MCA territories and in the bilateral cerebellar hemispheres, and the CblPR/CbrPR was calculated. All patients were prospectively followed for 5 years. The primary end points were stroke recurrence or death. RESULTS: A total of 17 patients exhibited the primary end points, 11 of whom experienced subsequent ipsilateral strokes. Multivariate analysis revealed that only high CblPR/CbrPR was significantly associated with the development of the primary end point or subsequent ipsilateral strokes (95% confidential limits [CIs], 1.130-3.145; P  =  0.0114 or 95% CIs, 2.558-5.140; P  =  0.0045, respectively). The CblPR/CbrPR provided 65% (11/17) or 91% (10/11) sensitivity and 88% (47/53) or 88% (52/59) specificity in predicting the primary end point or subsequent ipsilateral strokes, respectively. CONCLUSIONS: The CblPR/CbrPR on brain perfusion SPECT predicts 5-year outcomes in patients with symptomatic unilateral occlusion of the MCA or ICA.

Combined measurement of cerebral and cerebellar blood flow on preoperative brain perfusion SPECT imaging predicts development of new cerebral ischemic events after endarterectomy for symptomatic unilateral cervical carotid stenosis.

PURPOSE: The aim of this study was to determine whether the ratio of blood flow contralateral-to-affected asymmetry in the cerebellar hemisphere to blood flow affected-to-contralateral asymmetry in the middle cerebral artery (MCA) territory (AR(cbl)/AR(MCA)) on preoperative brain perfusion SPECT could identify patients at risk for new cerebral ischemic events after carotid endarterectomy (CEA) for symptomatic unilateral cervical carotid stenosis. For the purposes of this study, new cerebral ischemic events included neurological deficits and cerebral ischemic lesions on diffusion-weighted MRI. METHODS: Brain blood flow was assessed using 123I-IMP SPECT in 101 patients. A region of interest was automatically placed in the bilateral MCA territories and in the bilateral cerebellar hemispheres using a 3-dimensional stereotaxic region-of-interest template, and the AR(cbl)/AR(MCA) was calculated. Diffusion-weighted MRI was performed within 3 days before and 24 hours after surgery. Patients were neurologically tested before induction of general anesthesia and after recovery from general anesthesia. RESULTS: New cerebral ischemic events after CEA were observed in 12 patients (12%). Multivariate analysis revealed that only high AR(cbl)/AR(MCA) was significantly associated with the development of new postoperative cerebral ischemic events (95% confidence interval, 1.945-8.452; P = 0.0070). The AR(cbl)/AR(MCA) provided 75% sensitivity, 84% specificity, and 39% positive and 96% negative predictive values in predicting development of new postoperative cerebral ischemic events. CONCLUSIONS: The AR(cbl)/AR(MCA) on preoperative brain perfusion SPECT could identify patients at risk for new cerebral ischemic events after CEA for unilateral cervical carotid stenosis.