Tc99m-Sestamibi Thigh SPECT/CT Images for Noninvasive Assessment of Skeletal Muscle Injury in Carbon Monoxide Intoxication With Clinical and Pathological Correlation

Comparisons of vesicular monoamine transporter type 2 signals in Parkinson's disease and parkinsonism secondary to carbon monoxide poisoning

Parkinson's disease (PD) and carbon monoxide (CO) poisoning demonstrate parkinsonian features related to presynaptic dopaminergic deficits. However, their clinical features and treatment responses are different, indicating other roles of neurotransmitters in symptomatic modulation. In this study, we used ¹⁸F-FP-(+)-DTBZ PET to explore vesicular monoamine transporter type 2 (VMAT2) distributions in 31 patients with PD, 39 patients with CO poisoning and parkinsonian features (n = 39), and 24 age-matched controls. In addition to the disease-specific VMAT2 topographies in PD and CO poisoning, we also constructed feature-specific functional networks. The cardinal features included tremor, rigidity, akinesia, and rapid alternating movements (RAM), and the overall motor severity was scored using Unified Parkinson Disease Rating Scale (UPDRS) and modified Hoehn-Yahr (mH-Y) Scale scores. Our results suggested that a reduction in VMAT2 signals in the caudate, amygdala, and hippocampus were more specific to CO poisoning, while low uptake in the putamen and substantia nigra was more specific to PD. UPDRS and mH-Y scores were related to striatum signals in both groups and hippocampus and raphe in the CO poisoning group. With regards to the cardinal features, the putamen was related to akinesia in both groups. The substantia nigra was related to rigidity in PD, and the caudate and nucleus accumbens were related to akinesia, RAM and rigidity in CO poisoning. Our study enhances the current understanding of different patterns of monoaminergic terminal deficits in patients with CO poisoning and PD.

Efficacy of single-photon emission computed tomography aided botulinum toxin injection in cervical dystonia: A double-blind, randomized study

BACKGROUND

Although single-photon emission computed tomography (SPECT/CT) could help to predetermine dystonic muscles in patients with cervical dystonia (CD), its efficacy in aiding botulinum toxin injection is undetermined. This randomized, double-blinded study aimed to assess the efficacy of SPECT/CT aided botulinum toxin injection in CD.

METHODS

Patients were randomized into study group (candidate muscles selected by SPECT/CT and clinical evaluation) or control group (clinical evaluation). Follow-ups were done at two weeks (T1), one (T2), three (T3) and six months (T4). The primary outcomes included symptom improvement assessed using Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) and Tsui score at T2.

RESULTS

A total of 122 patients were enrolled and 108 patients accomplished the study. For primary outcomes, the study group had significantly better symptom improvement at T2 (TWSTRS: β, -4.86 [95%CI -9.40 to -0.32; P = 0.036]; Tsui: β, -1.65 [95%CI -2.77 to -0.54; P = 0.004]). For secondary outcomes, the study group also showed better outcomes at T1 (TWSTRS: β, -6.33 [95%CI -10.17 to -2.49; P = 0.001]; Tsui: β, -1.42 [95%CI -2.48 to -0.37; P = 0.008]) and T3 (TWSTRS: β, -6.05 [95%CI -11.09 to -1.01; P = 0.019]; Tsui: β, -1.24 [95%CI -2.40 to -0.08; P = 0.037]). The interval of re-injection was significantly longer in the study group than the control group (159.1 ± 28.6 versus 141.8 ± 51.0 days, P = 0.032).

CONCLUSIONS

SPECT/CT could improve the efficacy of botulinum toxin in CD. It could become a useful tool to aid botulinum toxin injection.

Predictive factors for acute brain lesions on magnetic resonance imaging in acute carbon monoxide poisoning

BACKGROUND

Acute brain lesions on diffusion-weighted-magnetic resonance imaging (MRI) after acute carbon monoxide (CO) poisoning were associated with delayed neurological sequelae. This study was conducted to identify the risk factors associated with acute brain lesions on MRI after acute CO poisoning and to help select patients who need acute-phase brain MRI after acute CO poisoning in the emergency department (ED).

METHODS

This retrospective observational study included 103 adult patients who were hospitalized at a tertiary-care hospital between November 2016 and September 2019 and underwent brain MRI because of acute CO poisoning. Multivariable logistic regression analysis was applied to identify predictive factors for acute brain lesions on MRI after acute CO poisoning.

RESULTS

Multivariable logistic regression analysis showed that Glasgow Coma Scale (GCS) score of <9 at ED presentation (odds ratio [OR] 17.749, 95% confidence interval [CI] 3.098-101.690, P = 0.001) and the initial troponin-I level at presentation in the ED (OR 13.657, 95% CI 1.415-131.834, P = 0.024) were predictive factors for acute brain lesions on MRI in acute CO poisoning. The receiver operating characteristics curve for initial troponin-I showed an area under the curve of 0.761 (95% CI 0.638-0.883, P < 0.001) and the optimal cutoff value was 0.105 ng/mL.

CONCLUSIONS

Acute-phase brain MRI in acute CO poisoning can be considered for patients who present at the ED with a GCS score <9 or troponin-I level >0.105 ng/mL.

[99mTc]MIBI SPECT/CT for Identifying Dystonic Muscles in Patients with Primary Cervical Dystonia

PURPOSE

This study aimed to evaluate the usefulness of [^99mTc]sestamibi ([^99mTc]MIBI) single photon emission computed tomography (SPECT)/X-ray computed tomography (CT) imaging for the identification of dystonic muscles in primary cervical dystonia (PCD) patients who underwent botulinum neurotoxin type A (BoNT-A) therapy.

PROCEDURES

Thirty-six patients with PCD and 10 healthy subjects (control group) who underwent [^99mTc]MIBI SPECT/CT were enrolled. The image characteristics of dystonic muscles and normal muscles were evaluated. Muscle/background ratio (MBR) of six representative muscles was calculated for dystonic muscles in PCD group and normal muscles in control group. In PCD patients, target muscles injected with BoNT-A were selected by clinical evaluations and the results of needle electromyography (EMG) were considered as the gold standard. The sensitivity, specificity, and diagnostic efficacy of SPECT/CT were obtained from the receiver operator characteristic (ROC) curve.

RESULTS

Twenty-four PCD patients were included in our study eventually, because three PCD patients whose follow-up were lost and 9 PCD patients whose maximum reduction of Tsui scale scores was < 80 % were ruled out. Normal muscles of healthy subjects showed mild symmetrical radioactivity distribution, while in PCD patients, [^99mTc]MIBI uptake in dystonic muscles abnormally increased. The mean MBRs of dystonic muscles were significantly higher than those of normal muscles. The sensitivity, specificity, and area under the curve (AUC) of SPECT/CT were 93.2 %, 88.5 %, and 0.908, respectively.

CONCLUSIONS

Our study indicated that [^99mTc]MIBI SPECT/CT may be a useful method for identifying dystonic muscles and a guide to BoNT-A therapy in PCD patients.

99mTc-sestamibi thigh SPECT/CT imaging for assessment of myopathy in cerebrotendinous xanthomatosis with histopathological and immunohistochemical correlation

PURPOSE

The aim of this study was to determine the effectiveness of using Tc-sestamibi thigh SPECT/CT imaging for evaluating myopathy in cerebrotendinous xanthomatosis (CTX).

PATIENTS AND METHODS

Four genetically proven CTX patients (Family I, Cases I-1 and I-2; Family II, Cases II-1 and II-2) were included. They all underwent muscle biopsies for histopathologic and ultrastructural studies. Immunohistochemical staining for vinculin expression was also performed. Tc-sestamibi thigh SPECT/CT imaging was conducted on all 4 CTX patients, and both visual interpretation and muscle-to-background (M/B) ratio count were applied for assessment. Correlation analysis of the imaging findings and results of the ultrastructural and immunohistochemical studies was done.

RESULTS

In the Tc-sestamibi thigh SPECT/CT imaging study, all 4 CTX cases had abnormal scores of visual interpretation and M/B ratios. The ultrastructural features of the skeletal muscle of the 4 CTX cases showed mitochondrial and membrane system abnormalities, with increased depositions of metabolites. They also had abnormal increases in vinculin expression after immunohistochemical staining of the skeletal muscle.

CONCLUSIONS

This is the first report on the use of Tc-sestamibi thigh SPECT/CT imaging to assess the mitochondrial status of CTX. The imaging findings may have a correlation with the ultrastructural and immunohistochemical findings on skeletal muscle. Although the Tc-sestamibi thigh SPECT/CT imaging is not specific for CTX, this noninvasive in vivo assessment can be an important tool for the detection and follow-up study of skeletal muscle involvement in CTX.

Toxic inhalational exposures

Respirable toxicants are a spectrum of irritant and nonirritant gases, vapors, fumes, and airborne particles that can be entrained into the body through the respiratory tract, resulting in exposures that cause pulmonary injury and/or systemic disease. Sources of respirable toxicants include structural fires, industrial accidents, domestic mishaps, and intentional releases of injurious agents on the battleground (warfare) or in civilian settings (acts of terrorism). Acute toxic inhalational exposures may result in respiratory failure, multisystem organ dysfunction, and death. Management of victims includes assessment and protection of the airway, monitoring and treatment of systemic toxicity, and delivery of exposure-specific and nonspecific therapies that improve outcomes. Treatments may include antidotes, hyperbaric oxygen, and other nonspecific life-supporting interventions.