Statistical parametric mapping and statistical probabilistic anatomical mapping analyses of basal/acetazolamide Tc-99m ECD brain SPECT for efficacy assessment of endovascular stent placement for middle cerebral artery stenosis

A Long-Term Outcome of Symptomatic Middle Cerebral Artery Undergoing Intracranial Angioplasty or Stenting

OBJECTIVE

For symptomatic stenosis in the middle cerebral artery (MCA), intracranial angioplasty and stenting are frequently employed. However, limited data exist regarding their long-term impact. Our study demonstrates the long-term advantages in preventing ischemic events through a 5-year follow-up period.

METHODS

A set of 41 individuals with symptomatic stenosis in the MCA who underwent angioplasty or stenting procedures between October 2004 and April 2018 at various hospitals in Southwest China were prospectively enrolled in the study. The rates of successful revascularization, complications, imaging observations, and clinical outcomes were systematically assessed.

RESULTS

A total of 41 individuals successfully underwent stenting, respectively. After stenting, the extent of stenosis was decreased from 71.8% (56-87.8%) to 24.9% (0-45%). The mean follow-up period is 36.9 ± 13.68 months (range, 11-67 months). There was no deterioration of neurological function or a new ischemic event. A DSA or CT angiography was conducted after the procedure and demonstrated no in-stent restenosis. No patient experienced restenosis below 50% during the mean follow-up period. The morbidity and mortality rates of the case series were 7.3% and 2.4%, respectively.

CONCLUSIONS

In the treatment of symptomatic MCA atherosclerotic stenoses, intracranial angioplasty and stenting are demonstrated to be technically feasible and safe. Its early and long-term efficacy on ischemic event prevention is acceptable, with a reduced level of restenosis, although the representative sample is tiny.

Basal and Acetazolamide Brain Perfusion SPECT in Internal Carotid Artery Stenosis

Internal carotid artery (ICA) stenosis including Moyamoya disease needs revascularization when hemodynamic insufficiency is validated. Vascular reserve impairment was the key to find the indication for endarterectomy/bypass surgery in the atherosclerotic ICA stenosis and to determine the indication, treatment effect, and prognosis in Moyamoya diseases. Vascular reserve was quantitatively assessed by 1-day split-dose I-123 IMP basal/acetazolamide SPECT in Japan or by Tc-99m HMPAO SPECT in other countries using qualitative or semi-quantitative method. We summarized the development of 1-day basal/ acetazolamide brain perfusion SPECT for ICA stenosis, both quantitative and qualitative methods, and their methodological issues regarding (1) acquisition protocol; (2) qualitative assessment, either visual or deep learning-based; (3) clinical use for atherosclerotic ICA steno-occlusive diseases and mostly Moyamoya diseases; and (4) their impact on the choice of treatment options. Trials to use CT perfusion or perfusion MRI using contrast materials or arterial spin labeling were briefly discussed in their endeavor to use basal studies alone to replace acetazolamide-challenge SPECT. Theoretical and practical issues imply that basal perfusion evaluation, no matter how much sophisticated, will not disclose vascular reserve. Acetazolamide rarely causes serious adverse reactions but included fatality, and now, we need to monitor patients closely in acetazolamide-challenge studies.

Automated Analysis of (123)I-beta-CIT SPECT Images with Statistical Probabilistic Anatomical Mapping

BACKGROUND

Population-based statistical probabilistic anatomical maps have been used to generate probabilistic volumes of interest for analyzing perfusion and metabolic brain imaging. We investigated the feasibility of automated analysis for dopamine transporter images using this technique and evaluated striatal binding potentials in Parkinson's disease and Wilson's disease.

MATERIALS AND METHODS

We analyzed 2β-Carbomethoxy-3β-(4-(123)I-iodophenyl)tropane ((123)I-beta-CIT) SPECT images acquired from 26 people with Parkinson's disease (M:F = 11:15, mean age = 49 ± 12 years), 9 people with Wilson's disease (M: F = 6:3, mean age = 26 ± 11 years) and 17 normal controls (M:F = 5:12, mean age = 39 ± 16 years). A SPECT template was created using striatal statistical probabilistic map images. All images were spatially normalized onto the template, and probability-weighted regional counts in striatal structures were estimated. The binding potential was calculated using the ratio of specific and nonspecific binding activities at equilibrium. Voxel-based comparisons between groups were also performed using statistical parametric mapping.

RESULTS

Qualitative assessment showed that spatial normalizations of the SPECT images were successful for all images. The striatal binding potentials of participants with Parkinson's disease and Wilson's disease were significantly lower than those of normal controls. Statistical parametric mapping analysis found statistically significant differences only in striatal regions in both disease groups compared to controls.

CONCLUSION

We successfully evaluated the regional (123)I-beta-CIT distribution using the SPECT template and probabilistic map data automatically. This procedure allows an objective and quantitative comparison of the binding potential, which in this case showed a significantly decreased binding potential in the striata of patients with Parkinson's disease or Wilson's disease.

Parametric Cerebrovascular Reserve Images Using Acetazolamide (99m)Tc-HMPAO SPECT: A Feasibility Study of Quantitative Assessment

PURPOSE

Basal/acetazolamide stress (99m)Tc-HMPAO single-photon emission computed tomography (SPECT) has been widely used for evaluation of hemodynamics; however, qualitative and subjective visual assessment of cerebrovascular reserve (CVR) has been performed in clinical settings. The aim of this study was to generate parametric CVR images and evaluate its feasibility of quantification.

METHODS

Basal/acetazolamide stress (99m)Tc-HMPAO SPECT data from 17 patients who underwent bypass surgery or percutaneous transluminal angioplasty were used. Spatial normalization was performed and parametric CVR images were generated using relative CVR (rCVR) of each voxel proportional to CVR of the whole brain. Binary parametric maps to show area of relatively reduced CVR were generated also using threshold of rCVR < 90 %. We calculated rCVR of internal carotid artery (ICA) using the parametric CVR images and probabilistic maps for ICA territory. Pre- and postprocedural parametric CVR images were obtained and quantitative rCVRs were compared. The rCVRs were evaluated according to visual grades for regional decreased CVR.

RESULTS

Postprocedural rCVR obtained from parametric CVR images increased significantly from preprocedural rCVR. The rCVR was significantly correlated with visual grades of reduced CVR for each side of ICA territories.

CONCLUSIONS

We generated parametric CVR images for basal/acetazolamide stress (99m)Tc-HMPAO SPECT. As a quantitative measurement, rCVR obtained from the parametric image was feasibly assessed hemodynamic abnormalities with preserved anatomical information.

Feasibility of PET Template-Based Analysis on F-18 FP-CIT PET in Patients with De Novo Parkinson's Disease

PURPOSE

The aim of this study was to evaluate the feasibility of FP-CIT PET template-based quantitative analysis on F-18 FP-CIT PET in patients with de novo Parkinson's disease (PD), compared with MR-based and manual methods. We also assessed the correlation of quantitative parameters of those methods with clinical severity of the disease.

METHODS

Forty patients with de novo PD underwent both MRI and F-18 FP-CIT PET. Images were spatially normalized to a standardized PET template. Mean counts of 4 ROIs: putamen, caudate, occipital cortex and cerebellum, were obtained using the quantification program, Korean Statistical Probabilistic Anatomical Map (KSPAM). Putamen-to-caudate ratio (PCR), asymmetry index (ASI), specific-to-nonspecific ratios with two different references: to occipital cortex (SOR) and cerebellum (SCR) were compared. Parameters were also calculated from manually drawn ROI method and MR-coregistrated method.

RESULTS

All quantitative parameters showed significant correlations across the three different methods, especially between the PET-based and manual methods. Among them, PET-based SOR and SCR values showed an excellent correlation and concordance with those of manual method. In relationship with clinical severity, only ASI achieved significantly inverse correlations with H&Y stage and UPDRS motor score. There was no significant difference between the quantitative parameters of both occipital cortex and cerebellum in all three methods, which implied that quantitation using PET-based method could be reproducible regardless of the reference region.

CONCLUSIONS

Quantitative parameters using FP-CIT PET template-based method correlated well with those using laborious manual method with excellent concordance. Moreover, PET-based quantitation was less influenced by the reference region than MR-based method. It suggests that PET-based method can provide objective and quantitative parameters quickly and easily as a feasible analysis in place of conventional method.

Quantification of Tc-99m-ethyl cysteinate dimer brain single photon emission computed tomography images using statistical probabilistic brain atlas in depressive end-stage renal disease patients: Correlation with disease severity and symptom factors

This study adapted a statistical probabilistic anatomical map of the brain for single photon emission computed tomography images of depressive end-stage renal disease patients. This research aimed to investigate the relationship between symptom clusters, disease severity, and cerebral blood flow. Twenty-seven patients (16 males, 11 females) with stages 4 and 5 end-stage renal disease were enrolled, along with 25 healthy controls. All patients underwent depressive mood assessment and brain single photon emission computed tomography. The statistical probabilistic anatomical map images were used to calculate the brain single photon emission computed tomography counts. Asymmetric index was acquired and Pearson correlation analysis was performed to analyze the correlation between symptom factors, severity, and regional cerebral blood flow. The depression factors of the Hamilton Depression Rating Scale showed a negative correlation with cerebral blood flow in the left amygdale. The insomnia factor showed negative correlations with cerebral blood flow in the left amygdala, right superior frontal gyrus, right middle frontal gyrus, and left middle frontal gyrus. The anxiety factor showed a positive correlation with cerebral glucose metabolism in the cerebellar vermis and a negative correlation with cerebral glucose metabolism in the left globus pallidus, right inferior frontal gyrus, both temporal poles, and left parahippocampus. The overall depression severity (total scores of Hamilton Depression Rating Scale) was negatively correlated with the statistical probabilistic anatomical map results in the left amygdala and right inferior frontal gyrus. In conclusion, our results demonstrated that the disease severity and extent of cerebral blood flow quantified by a probabilistic brain atlas was related to various brain areas in terms of the overall severity and symptom factors in end-stage renal disease patients.

Computer-assisted lateralization of unilateral temporal lobe epilepsy using Z-score parametric F-18 FDG PET images

BACKGROUND

To evaluate the use of unbiased computer-assisted lateralization of temporal lobe epilepsy (TLE) by z-score parametric PET imaging (ZPET).

METHODS

38 patients with histologically proven unilateral TLE due to pure hippocampal sclerosis, referred for pre-surgical PET evaluation of intractable seizure over a 5-year period, were included. The F-18 FDG images were oriented along temporal long axis and then transformed into ZPET images on a voxel by voxel basis. Multiple regions of interests (21 in total) were placed on cortical, subcortical and cerebellar structures on twenty-eight out of 38 patients with totally seizure-free (class I) outcome. Paired t-tests with Bonferroni correction were used to determine the location of the most asymmetric regions as variables for subsequent discriminant analysis of the entire group of the patients.

RESULTS

The computer program identified the anterior half of the temporal lobe (p < 0.0005) and thalami (p = 0.021) as the most asymmetric regions in TLE patients with Class I outcome. Discriminant analysis using z-scores from a total of 8 ROIs (in 4 pairs) on these structures correctly lateralized thirty-seven out of 38 (97%) patients (sensitivity = 94%; specificity = 100%). The only false localization came from a patient with equivocal z-scores on the temporal lobes and this patient turned out to have poor outcome.

CONCLUSION

The computer-assisted lateralization of TLE using ZPET provides an accurate, fast and objective way of seizure evaluation.