Quantification of regional cerebral blood flow and vascular reserve in childhood moyamoya disease using [123I]IMP-ARG method

Outcome prediction of pediatric moyamoya disease using midterm cerebral blood flow measured between staged anastomoses

PURPOSE

Cognitive outcomes of pediatric moyamoya disease are variable and difficult to predict on the basis of initial neurological signs and examinations. To determine the best early time point for outcome prediction, we retrospectively analyzed the correlation between cognitive outcomes and the cerebrovascular reserve capacity (CRC) measured before, between, and after staged bilateral anastomoses.

METHODS

Twenty-two patients aged 4-15 years were included in this study. CRC was measured before the first hemispheric surgery (preoperative CRC), 1 year after the first surgery (midterm CRC), and 1 year after the surgery on the other side (final CRC). The cognitive outcome was the Pediatric Cerebral Performance Category Scale (PCPCS) grade more than 2 years after the final surgery.

RESULTS

The 17 patients with favorable outcomes (PCPCS grades 1 or 2) showed a preoperative CRC of 4.9% ± 11.2%, which was not better than that of the five patients with unfavorable outcomes (grade 3; 0.3% ± 8.5%, p = 0.5). The 17 patients with favorable outcomes showed a midterm CRC of 23.8% ± 15.3%, which was significantly better than that of the five patients with unfavorable outcomes (-2.5% ± 12.1%, p = 0.004). The difference was much more significant for the final CRC, which was 24.8% ± 13.1% in the patients with favorable outcomes and -11.3% ± 6.7% in those with unfavorable outcomes (p = 0.00004).

CONCLUSION

Cognitive outcomes were first clearly discriminated by the CRC after the first-side unilateral anastomosis, which is the optimal early timing for the prediction of individual prognosis.

Quantitative Assessment of the Intracranial Vasculature of Infants and Adults Using iCafe (Intracranial Artery Feature Extraction)

Comprehensive quantification of intracranial artery features may help to assess and understand regional variations of blood supply during early brain development and aging. We analyzed vasculature features of 27 healthy infants during natural sleep, 13 infants at 7-months (7.3 ± 1.0 month), and 14 infants at 12-months (11.7 ± 0.4 month), and 13 older healthy, awake adults (62.8 ± 8.7 years) to investigate age-related vascular differences as a preliminary study of vascular changes associated with brain development. 3D time-of-flight (TOF) magnetic resonance angiography (MRA) acquisitions were processed in iCafe, a technique to quantify arterial features (http://icafe.clatfd.cn), to characterize intracranial vasculature. Overall, adult subjects were found to have increased ACA length, tortuosity, and vasculature density compared to both 7-month-old and 12-month-old infants, as well as MCA length compared to 7-month-old infants. No brain laterality differences were observed for any vascular measures in either infant or adult age groups. Reduced skull and brain sharpness, indicative of increased head motion and brain/vascular pulsation, respectively, were observed in infants but not correlated with length, tortuosity, or vasculature density measures. Quantitative analysis of TOF MRA using iCafe may provide an objective approach for systematic study of infant brain vascular development and for clinical assessment of adult and pediatric brain vascular diseases.

Can Combined Bypass Surgery at Middle Cerebral Artery Territory Save Anterior Cerebral Artery Territory in Adult Moyamoya Disease?

Background

Patients with moyamoya disease are frequently encountered with improved symptoms related to anterior cerebral artery territory (ACAt) and middle cerebral artery territory (MCAt) after bypass surgery at MCAt.

Objective

To evaluate hemodynamic changes in MCAt and ACAt after bypass surgery in adult moyamoya disease.

Methods

Combined bypass surgery was performed on 140 hemispheres in 126 patients with MCAt symptoms. Among them, 87 hemispheres (62.1%) accompanied preoperative ACAt symptoms. Clinical, hemodynamic, and angiographic states were evaluated preoperatively and approximately 6 months after surgery.

Results

Preoperative symptoms resolved in 127 MCAt (90.7%) and 82 ACAt (94.3%). Hemodynamic analysis of total patients showed a significant improvement in MCAt basal perfusion and reservoir capacity ( P < .001 and P = .002, respectively) and ACAt basal perfusion ( P = .001). In a subgroup analysis, 82 hemispheres that completely recovered from preoperative ACAt symptoms showed a significant improvement in MCAt basal perfusion and reservoir capacity ( P < .001 and P = .05, respectively) and ACAt basal perfusion ( P = .04). Meanwhile, 53 hemispheres that had never experienced ACAt symptoms significantly improved MCAt basal perfusion and reservoir capacity ( P < .001 and P = .05, respectively); however, no ACAt changes were observed. A qualitative angiographic analysis demonstrated a higher trend of leptomeningeal formation from MCAt to ACAt in the former subgroup ( P = .05). During follow-up, no ACAt infarctions were observed.

Conclusion

Combined bypass surgery at MCAt resulted in hemodynamic improvements in ACAt and MCAt, especially in patients with preoperative ACAt symptoms.

Clinical Significance of the Champagne Bottle Neck Sign in the Extracranial Carotid Arteries of Patients with Moyamoya Disease

BACKGROUND AND PURPOSE

The champagne bottle neck sign represents a rapid reduction in the extracranial ICA diameters and is a characteristic feature of Moyamoya disease. However, the clinical significance of the champagne bottle neck sign is unclear. We investigated the relationship between the champagne bottle neck sign and the clinical and hemodynamic stages of Moyamoya disease.

MATERIALS AND METHODS

We analyzed 14 patients with Moyamoya disease before revascularization (5 men, 9 women; age, 43.2 ± 19.3 years). The ratio of the extracranial ICA and common carotid artery diameters was determined using carotid ultrasonography or cerebral angiography; a ratio of < 0.5 was considered champagne bottle neck sign-positive. The clinical disease stage was determined using the Suzuki angiographic grading system. CBF and cerebral vasoreactivity also were measured.

RESULTS

The ICA/common carotid artery ratio (expressed as median [interquartile range]) decreased as the clinical stage advanced (stages I-II, 0.71 [0.60-0.77]; stages III-IV, 0.49 [0.45-0.57]; stages V-VI, 0.38 [0.34-0.47]; P < .001). Lower ICA/common carotid artery ratio tended to occur in symptomatic versus asymptomatic arteries (0.47 [0.40-0.53] versus 0.57 [0.40-0.66], respectively; P = .06). Although the ICA/common carotid artery ratio was not related to cerebral perfusion, it decreased as cerebral vasoreactivity decreased (P < .01). All champagne bottle neck sign-positive arteries were classified as Suzuki stage ≥III, 73% were symptomatic, and 89% exhibited reduced cerebral vasoreactivity. In contrast, all champagne bottle neck sign-negative arteries were Suzuki stage ≤III, 67% were asymptomatic, and all showed preserved cerebral vasoreactivity.

CONCLUSIONS

The champagne bottle neck sign was related to advanced clinical stage, clinical symptoms, and impaired cerebral vasoreactivity. Thus, detection of the champagne bottle neck sign might be useful in determining the clinical and hemodynamic stages of Moyamoya disease.

Risk Factors for Newly Developed Cerebral Infarction After Surgical Revascularization for Adults with Moyamoya Disease

OBJECTIVE

It is important to recognize the incidence and risk factors for ischemic complications after surgical revascularization for moyamoya disease (MMD). However, most studies focus on pediatric MMD or pediatric and adult MMD. Our study identified the incidence and risk factors of newly developed cerebral infarction after surgical revascularization for adult MMD.

METHODS

Ischemic complications were defined as newly developed cerebral infarction within 15 days after surgery, as identified by imaging studies. To identify the incidence and these risk factors for adult patients ≥18 years, we retrospectively reviewed our experience with 194 adult MMD patients with 241 surgical revascularizations.

RESULTS

The incidence of symptomatic infarction after surgical revascularization was 5.8% (14 cases); 30 cases (12.4%) experienced a silent infarction. In univariate analysis, initial presentation as infarction, initial presentation as hemorrhage, transient ischemic attacks (TIAs) >3 times/month, involvement of the posterior cerebral artery (PCA), combined bypass, and using muscle for revascularization were variables related to the newly developed cerebral infarction. Multivariate analysis revealed that the following factors were independently associated with newly developed cerebral infarction after surgery: cerebral infarction as initial presentation (odds ratio [OR] 1.150; 95% confidence interval [CI] 1.038-1.273; P = 0.0073), TIAs >3times/month (OR 1.188; 95% CI 1.058-1.335; P = 0.0035), and PCA involvement (OR 1.095; 95% CI 1.005-1.194; P = 0.039).

CONCLUSIONS

Our findings demonstrate that newly developed, silent cerebral infarction developed more frequently than symptomatic cerebral infarction in adult patients. Cerebral infarction as initial presentation, frequent TIA before surgery, and PCA involvement were also independent risk factors for newly developed cerebral infarction after surgical revascularization for adult MMD.

Reliability of laser speckle flow imaging for intraoperative monitoring of cerebral blood flow during cerebrovascular surgery: comparison with cerebral blood flow measurement by single photon emission computed tomography

OBJECTIVE

To determine the clinical utility of laser speckle flow imaging (LSFI) and its comparability to (123)I-iodoamphetamine single photon emission computed tomography (IMP-SPECT), we used LSFI to monitor cerebral blood flow (CBF) during extracranial-intracranial (EC-IC) bypass surgery.

METHODS

Intraoperative intensity of CBF (iCBF) by LSFI and preoperative and postoperative CBF by IMP-SPECT were measured in 3 patients with internal carotid artery (ICA) aneurysms who were undergoing ICA trapping surgery and in 16 patients with major cerebral artery occlusion who were undergoing EC-IC bypass surgery.

RESULTS

The decrease in iCBF (16.9% ± 2.3%) with ICA interruption was equivalent to the decrease in CBF during the preoperative balloon test occlusion, as measured by IMP-SPECT (12.2% ± 4.4%). Whether preserved iCBF in LSFI promised postoperative intact CBF was not determined, as no patient showed ischemic tolerance by ICA occlusion. The increase in iCBF resulting from EC-IC bypass correlated moderately with the increase in postoperative CBF as measured by IMP-SPECT. However, the increase in iCBF was too small to be recognized intraoperatively by visual inspection.

CONCLUSIONS

Although LSFI clearly demonstrated a decrease in CBF, the information is taken only from the surface of the brain. Combined use of LFSI with an electrophysiologic examination is required for intraoperative diagnosis of ischemia. LSFI was not sensitive enough to detect increased CBF by superficial temporal artery-to-middle cerebral artery anastomosis, because CBF changes are minimized during anesthesia, probably owing to low metabolic activity.

Usefulness of the automatic quantitative estimation tool for cerebral blood flow: clinical assessment of the application software tool AQCEL

OBJECTIVE

AQCEL enables automatic reconstruction of single-photon emission computed tomogram (SPECT) without image degradation and quantitative analysis of cerebral blood flow (CBF) after the input of simple parameters. We ascertained the usefulness and quality of images obtained by the application software AQCEL in clinical practice.

METHODS

Twelve patients underwent brain perfusion SPECT using technetium-99m ethyl cysteinate dimer at rest and after acetazolamide (ACZ) loading. Images reconstructed using AQCEL were compared with those reconstructed using conventional filtered back projection (FBP) method for qualitative estimation. Two experienced nuclear medicine physicians interpreted the image quality using the following visual scores: 0, same; 1, slightly superior; 2, superior. For quantitative estimation, the mean CBF values of the normal hemisphere of the 12 patients using ACZ calculated by the AQCEL method were compared with those calculated by the conventional method. The CBF values of the 24 regions of the 3-dimensional stereotaxic region of interest template (3DSRT) calculated by the AQCEL method at rest and after ACZ loading were compared to those calculated by the conventional method.

RESULTS

No significant qualitative difference was observed between the AQCEL and conventional FBP methods in the rest study. The average score by the AQCEL method was 0.25 ± 0.45 and that by the conventional method was 0.17 ± 0.39 (P = 0.34). There was a significant qualitative difference between the AQCEL and conventional methods in the ACZ loading study. The average score for AQCEL was 0.83 ± 0.58 and that for the conventional method was 0.08 ± 0.29 (P = 0.003). During quantitative estimation using ACZ, the mean CBF values of 12 patients calculated by the AQCEL method were 3-8% higher than those calculated by the conventional method. The square of the correlation coefficient between these methods was 0.995. While comparing the 24 3DSRT regions of 12 patients, the squares of the correlation coefficient between AQCEL and conventional methods were 0.973 and 0.986 for the normal and affected sides at rest, respectively, and 0.977 and 0.984 for the normal and affected sides after ACZ loading, respectively.

CONCLUSIONS

The quality of images reconstructed using the application software AQCEL were superior to that obtained using conventional method after ACZ loading, and high correlations were shown in quantity at rest and after ACZ loading. This software can be applied to clinical practice and is a useful tool for improvement of reproducibility and throughput.

Unilateral hemispheric proliferation of ivy sign on fluid-attenuated inversion recovery images in moyamoya disease correlates highly with ipsilateral hemispheric decrease of cerebrovascular reserve

BACKGROUND AND PURPOSE

An ivy sign is considered to represent diffuse leptomeningeal collaterals found on fluid-attenuated inversion recovery (FLAIR) images of patients with Moyamoya disease. We evaluated the correlation between unilateral ivy proliferation in a hemisphere and cerebrovascular hemodynamic status to learn the clinical significance of the ivy sign.

MATERIALS AND METHODS

A total of 35 patients with Moyamoya disease were included. Correlation between ivy dominance on FLAIR images and hemodynamic status with use of iodine 123 N-isopropyl-p-iodoamphetamine ((123)I-IMP) single-photon emission CT (SPECT) was evaluated.

RESULTS

Distributional differences of ivy signs between both hemispheres were observed in 22 (64.7%) of 34 patients with a positive ivy sign, all of whom showed decreased vascular reserve/reactivity in the ivy-dominant hemisphere (IDH). The proportion of the stage II (misery perfusion) area to IDH was higher than that in the ivy less-dominant hemisphere (ILDH) in the quantitative analysis. The mean vascular reserve was lower in IDH than ILDH. There were 15 of 22 patients who had bypass surgery on IDH because of transient ischemic attack from ischemia of IDH. Patients with symmetric ivy distributions showed a variety of hemodynamic status. MR angiography (MRA) stage of IDH (2.95 +/- 0.39) was higher compared with ILDH (2.60 +/- 0.50; P < .05). Regional arteriocapillary circulation time ratio in IDH was longer compared with ILDH (P < .05). Ivy proliferation decreased in 10 (55.6%) of 18 patients who underwent bypass surgery during the follow-up period.

CONCLUSIONS

Unilateral hemispheric ivy proliferation correlated highly with the existence of an ipsilateral decreased vascular reserve associated with the development of leptomeningeal collaterals in patients with Moyamoya disease.

The contribution of imaging in diagnosis, preoperative assessment, and follow-up of moyamoya disease

The aim of this review was to evaluate the imaging tools used in diagnosis and perioperative assessment of moyamoya disease, with particular attention to the last decade.

The leptomeningeal "ivy sign" on fluid-attenuated inversion recovery MR imaging in Moyamoya disease: a sign of decreased cerebral vascular reserve?

BACKGROUND AND PURPOSE

Moyamoya disease is an idiopathic occlusive cerebrovascular disorder with abnormal microvascular proliferation. We investigated the clinical utility of leptomeningeal high signal intensity (ivy sign) sometimes seen on fluid-attenuated inversion recovery images in Moyamoya disease.

MATERIALS AND METHODS

We examined the relationship between the degree of the ivy sign and the severity of the ischemic symptoms in 96 hemispheres of 48 patients with Moyamoya disease. We classified each cerebral hemisphere into 4 regions from anterior to posterior. In 192 regions of 24 patients, we examined the relationship between the degree of the ivy sign and findings of single-photon emission CT, including the resting cerebral blood flow (CBF) and cerebral vascular reserve (CVR).

RESULTS

The degree of the ivy sign showed a significant positive relationship with the severity of the ischemic symptoms (P < .001). Of the 4 regions, the ivy sign was most frequently and prominently seen in the anterior part of the middle cerebral artery region. The degree of the ivy sign showed a negative relationship with the resting CBF (P < .0034) and a more prominent negative relationship with the CVR (P < .001).

CONCLUSIONS

The leptomeningeal ivy sign indicates decreased CVR in Moyamoya disease.

Quantification of the regional cerebral blood flow and vascular reserve in moyamoya disease using split-dose iodoamphetamine I 123 single-photon emission computed tomography

OBJECTIVES

We quantified the rCBF and regional vascular reserve (CVR) in adult patients with moyamoya disease before and after surgery using IMP I 123 SPECT.

METHODS

The patient population included 5 adult patients with ages at presentation ranging between 23 and 42 years. One patient had stroke, whereas 4 patients had transient ischemic attacks.

RESULTS

Before surgery, the mean resting rCBF and mean CVR in the frontal, parietal, and temporal lobes of the surgically treated hemisphere were 40.09, 39.50, and 36.9 mL/100 g per minute and 15.39%, 27.09%, and 28.92%, respectively. After surgery, the rCBF increased significantly (P = .0002, .0005, and .0062), but in a CVR evaluation, only the frontal lobe increased significantly (P = .0055). In the unaffected hemispheres, the mean resting rCBF significantly increased only in the frontal lobe (P = 038) and no significant increase in the CVR was observed after surgery. In 2 patients who showed steal phenomenon induced by acetazolamide administration, CVR significantly increased not only in the frontal lobe but also in the parietal and temporal lobe after surgery, although the CVR in these areas significantly decreased both before and after surgery in comparison to the mean CVR in all patients.

CONCLUSIONS

The frontal lobe showed severe hemodynamic ischemia. The cerebral hemodynamics in patients with moyamoya disease improved after surgical intervention, especially in severely damaged patients. Split-dose (123)I-IMP SPECT was therefore found to be a useful diagnostic modality for quantifying the hemodynamics of moyamoya disease.

Hemorrhage predisposing to cerebral infarction in children with moyamoya disease

Two children with a new diagnosis of hemorrhagic type moyamoya disease experienced cerebral infarction after intraventricular hemorrhage. The patients developed ischemia 15 and 2 days after the initial diagnosis of hemorrhage. No provocative factor such as hypoperfusion was identified, but both patients exhibited signs of increased intracranial pressure on computed tomographic scan before infarction. Increased intracranial pressure in the setting of hemorrhage may be a risk factor for ischemic complications in patients with moyamoya disease. The optimal acute management of these patients requires further study.

Assessment of cerebral hemodynamics in childhood moyamoya disease using a quantitative and a semiquantitative IMP-SPECT study

BACKGROUND

We evaluated the cerebral hemodynamics in childhood moyamoya disease patients before and after surgery to assess both surgical indication and the effect of revascularization using single photon emission computed tomography (SPECT) study with N-isopropyl-p-123I-iodoamphetamine (IMP). We compared results of quantitative and semi-quantitative SPECT studies to determine parameters by the semi-quantitative method to define severe hemodynamic ischemia.

METHODS

There were 14 pediatric patients with moyamoya disease who suffered transient ischemic attacks (TIAs) in the anterior circulation. Before and after surgical revascularization by STA-MCA bypass and encephalomyosynangiosis (EMS), quantitative IMP-SPECT studies using the autoradiographic method (IMP-ARG method) were performed. Resting regional cerebral blood flow (rCBF) and regional vascular reserve (rVR) were measured in bilateral cortical territories (ROI) and cerebellum. Semi-quantitative parameters were calculated from the ratio of ROI counts to the dominant cerebellar counts (ROI/Ce ratio) at resting and acetazolamide-activated conditions.

RESULTS

Before surgery, the mean resting rCBF and rVR in bilateral ACA and MCA territories were less than 40 ml/100 g/min and less than 10%, respectively, indicating severe hemodynamic ischemia. Except for the ACA territories, both the mean resting rCBF and mean rVR values in the entire cortex increased significantly after surgery (p < 0.05). By semi-quantitative studies, before surgery, the mean resting and acetazolamide-activated ROI/Ce ratios in bilateral ACA and MCA territories were less than 0.90 and 0.80, respectively. The mean resting and acetazolamide-activated ROI/Ce ratios increased significantly in the MCA territory after surgery. Severe hemodynamic ischemia, which categorized by the quantitative thresholds (resting rCBF < 40 ml/100 g/min and rVR < 10%) was diagnosed by the semi-quantitative thresholds (resting ROI/ Ce ratio < 0.90 and acetazolamide-activated ROI/Ce ratio < 0.85), the sensitivity and specificity of which were 87.5% and 90.9%, respectively.

CONCLUSIONS

The cerebral hemodynamics in childhood moyamoya disease was improved entirely after surgery. Severe hemodynamic cerebral ischemia was diagnosed by not only quantitative but also semi-quantitative IMP-SPECT studies.