Shu-Hua Huang

A comparative study of fused FDG PET/MRI, PET/CT, MRI, and CT imaging for assessing surrounding tissue invasion of advanced buccal squamous cell carcinoma.

Purpose: This study aimed to evaluate the diagnostic value of fused fluorodeoxyglucose positron emission tomography and magnetic resonance imaging (PET/MRI) compared with PET/computed tomography (CT), MRI, and CT in assessing surrounding tissue invasion of advanced buccal squamous cell carcinoma (BSCC). Materials and Methods: PET/CT and MRI were performed in 17 consecutive patients with suspected masticator space invasion of BSCC from CT images. Attenuation-corrected PET and head and neck MRI datasets were registered. For pathologic correlation, 4 regions of interest were examined, including the maxilla, mandible, pterygoid, and masseter muscle. The tumor maximal diameter, measured by different imaging modalities, was correlated with pathology results. Results: All PET/MRI fusions were verified as well matched using specific anatomic criteria. For pathology results, 1 patient had inflammation only, 1 had spindle cell cancer, and 15 had squamous cell cancer. Of 64 regions of interest, 20 (31.3%) harbored tumor invasion. The likelihood ratio was highest in fused PET/MRI (42.56) compared with PET/CT (25.02), MRI (22.94), and CT (8.6; all P < 0.05). The sensitivity and specificity of fused PET/MRI were also highest among the 4 modalities (90.0%/90.9%, 80.0%/84.1%, 80.0%/79.5%, and 55.0%/81.8%, respectively). The level of confidence was higher in fused PET/MRI or MRI than in PET/CT or CT (85.9%, 85.9%, 70.3%, 73.4%, respectively). The maximal lesion size was 3.0 to 6.0 cm in the pathology specimen. Regression analysis showed better agreement between fused PET/MRI and pathology results. Conclusions: Fused PET/MRI is more reliable for focal invasion assessment and tumor size delineation in advanced BSCC compared with PET/CT, MRI, and CT. PET/CT has the lowest confidence level, which may limit its use in the clinical setting.

Cognitive Severity-Specific Neuronal Degenerative Network in Charcoal Burning Suicide-Related Carbon Monoxide Intoxication: A Multimodality Neuroimaging Study in Taiwan

AbstractWhile carbon monoxide (CO) intoxication often triggers multiple intraneuronal immune- or inflammatory-related cascades, it is not known whether the pathological processes within the affected regions evolve equally in the long term. To understand the neurodegenerative networks, we examined 49 patients with a clinical diagnosis of CO intoxication related to charcoal burning suicide at the chronic stage and compared them with 15 age- and sex-matched controls. Reconstructions of degenerative networks were performed using T1 magnetic resonance imaging, diffusion-tensor imaging, and fluorodeoxyglucose positron emission tomography (PET). Tract-specific fractional anisotropy (FA) quantification of 11 association fibers was performed while the clinical significance of the reconstructed structural or functional networks was determined by correlating them with the cognitive parameters. Compared with the controls, the patients had frontotemporal gray matter (GM) atrophy, diffuse white matter (WM) FA decrement, and axial diffusivity (AD) increment. The patients were further stratified into 3 groups based on the cognitive severities. The spatial extents within the frontal-insular-caudate GM as well as the prefrontal WM AD increment regions determined the cognitive severities among 3 groups. Meanwhile, the prefrontal WM FA values and PET signals also correlated significantly with the patients Mini-Mental State Examination score. Frontal hypometabolic patterns in PET analysis, even after adjusted for GM volume, were highly coherent to the GM atrophic regions, suggesting structural basis of functional alterations. Among the calculated major association bundles, only the anterior thalamic radiation FA values correlated significantly with all chosen cognitive scores. Our findings suggest that fronto-insular-caudate areas represent target degenerative network in CO intoxication. The topography that occurred at a cognitive severity-specific level at the chronic phase suggested the clinical roles of frontal areas. Although changes in FA are also diffusely distributed, different regional changes in AD suggested unequal long-term compensatory capacities among WM bundles. As such, the affected WM regions showing irreversible changes may exert adverse impacts to the interconnected GM structures.

Impact of homocysteine on cortical perfusion and cognitive decline in mild Alzheimer's dementia

Elevated plasma total homocysteine level (tHcy) is associated with increased risk of dementia via increased white matter changes or reduction in cortical volume. Whether tHcy has an independent impact on regional perfusion and if it can predict a more rapid cognitive decline in mild Alzheimer dementia (AD) warrants investigation.

The incidence and risk of second primary cancers in patients with nasopharyngeal carcinoma: a population-based study in Taiwan over a 25-year period (1979–2003)

BACKGROUND Very few reports are available on the incidence and risk of second primary cancers in nasopharyngeal carcinoma (NPC) cases, and most of these are single-institution reviews with relatively small case numbers and short follow-up. PATIENTS AND METHODS A population-based study was conducted. We quantified standardized incidence ratios (SIRs) and cumulative incidence of second cancers among 23 639 individuals with initial diagnoses of NPC. RESULTS We found a 24% increased risk of second cancers in NPC patients compared with the general population [SIR = 1.24, 95% confidence interval 1.15-1.33]. Elevated SIRs were observed in the following second primary cancers: oral/pharyngeal, salivary gland, sarcoma, skin and leukemia/lymphoma. The cumulative incidence >10 years was 3.26%. The risk was higher in younger patients, especially those <40 years old. After diagnosis of second cancers, the median survival time was 1.7 years. CONCLUSIONS This is the largest population-based study to date from a high-incidence area. We found that NPC is associated with an increased risk of second malignancies, which had a negative impact on the survival of patients who survived NPC.

Cerebrotendinous Xanthomatosis Patients With and Without Parkinsonism: Clinical Characteristics and Neuroimaging Findings

Parkinsonism in cerebrotendinous xanthomatosis (CTX) is rare. There are no published studies with imaging findings of dopamine transporter using 99mTc‐[2‐[[2‐[[[3‐(4‐chlorophenyl)‐8‐methyl‐8‐azabicyclo [3,2,1] oct‐2‐yl] methyl] (2‐mercaptoethyl) amino] ethyl] amino]‐ethanethiolato(3‐)‐N2,N2,S2,S2]oxo‐[1R‐(exo‐exo)] (99mTc‐TRODAT‐1) SPECT in CTX patients. This report is on the clinical details of five genetically‐proven CTX patients (two with and three without parkinsonism). Imaging findings using cranial magnetic resonance (MR) imaging and 99mTc‐TRODAT‐1 SPECT are also shown. Clinical correlation of neuroimaging findings and clinical presentations was made. A literature review of the clinical and neuroimaging features of eight CTX patients with parkinsonism reported in the English literature is also presented. The parkinsonian features of our two cases and the other eight reported cases occurred before the age of 50 years. The MR imaging study showed variable findings, in which, besides the common diffuse cerebral and cerebellar white matter lesions shown in CTX, several focal brain lesions were also noted. Of the focal lesions, substantia nigra abnormalities were seen only in the two cases with parkinsonism. The 99mTc‐TRODAT‐1 SPECT study showed different degrees of unilateral or bilateral abnormalities in the striatal binding in both visual and semiquantitative assessments. parkinsonism can be one of the neurologic presentations of CTX. Even though abnormal findings of the substantia nigra were detected in both of our CTX patients with parkinsonism, basal ganglion lesions have not been uniformly described in MR imaging findings of reported CTX patients with parkinsonism. 99mTc‐TRODAT‐1 SPECT study can be of value in the detection of striatal involvement, and the study results also suggest pre‐synaptic dopamine neuron involvement in CTX patients with parkinsonism.

Clinical significance of the pallidoreticular pathway in patients with carbon monoxide intoxication

Whereas globus pallidus lesions resulting from carbon monoxide intoxication have been extensively described in the literature, the clinical significance of pallidoreticular lesions has rarely been mentioned. This study incorporated information from functional and structural imaging to explore the correlations of pallidoreticular lesions with parkinsonian features and neurobehavioural performance. Twenty-five patients (11 males) with globus pallidus lesions after carbon monoxide intoxication and 25 age- and sex-matched controls were enrolled for detailed neurological examinations, cognitive testing, susceptibility weighted imaging, diffusion tensor imaging and 99mTc-TRODAT-1 single photon emission computed tomography. The post-processing analysis of the neuroimaging included voxel-based morphometry to assess the regional atrophy, tract-based spatial statistics related to white matter involvement, tractography to investigate the rostral and caudal projections from the midbrain level and specific uptake ratios of 99mTc-TRODAT-1 for presynaptic dopaminergic transporter activity. In susceptibility weighted imaging, low-intensity pallidoreticular lesions were detected from the minimal-intensity projections, which were visible in only 7.7% of the T(1)-weighted images and 15.4% of the T(2)-weighted images, whereas inhomogeneous intensities were detected in the globus pallidus. The patients were further divided into two subgroups based on the presence (n = 13) or absence (n = 12) of pallidoreticular lesions. The patients with pallidoreticular lesions showed increased parkinsonian features, poorer performances on the neuropsychiatric tests, lower 99mTc-TRODAT-1 availability in both the caudate and the putamen and greater atrophy of the thalamus, posterior corpus callosum, cerebral peduncle and white matter surrounding the globus pallidus compared to those without pallidoreticular lesions. The tractography results obtained with seed regions of interest in the substantia nigra showed rostral projections to the supplementary motor cortex and anterior cingulate cortex via the globus pallidus; the two pathways were distinct but ran in parallel, caudal to the level of the globus pallidus. In conclusion, the presence of pallidoreticular lesions after carbon monoxide intoxication indicates a poorer cognitive state, which is associated with extensive grey and white matter damage in addition to the damage to the nigra-striatal neuronal networks. The presence of parkinsonian features may be related to pallidal and presynaptic dopaminergic dysfunction. The sensitivity for detecting pallidoreticular lesions can be greatly improved by using susceptibility weighted imaging compared with conventional imaging.

Multi-parametric neuroimaging evaluation of cerebrotendinous xanthomatosis and its correlation with neuropsychological presentations

BackgroundCerebrotendinous xanthomatosis (CTX) is a rare genetic disorder. Recent studies show that brain damage in CTX patients extends beyond the abnormalities observed on conventional magnetic resonance imaging (MRI). We studied the MRI and 99 mTc-ethyl cysteinate dimer single photon emission computed tomography (SPECT) findings of CTX patients and made a correlation with the neuropsychological presentations.MethodsDiffusion tensor imaging (DTI) and 3D T1-weighted images of five CTX patients were compared with 15 age-matched controls. Voxel-based morphometry (VBM) was use to delineate gray matter (GM) and white matter (WM) volume loss. Fractional anisotropy (FA), mean diffusivity (MD), and eigenvalues derived from DTI were used to detect WM changes and correlate with neuropsychological results. SPECT functional studies were used to correlate with GM changes.ResultsCognitive results showed that aside from moderate mental retardation, the patient group performed worse in all cognitive domains. Despite the extensive GM atrophy pattern, the cerebellum, peri-Sylvian regions and parietal-occipital regions were correlated with SPECT results. WM atrophy located in the peri-dentate and left cerebral peduncle areas corresponded with changes in diffusion measures, while axial and radial diffusivity suggested both demyelinating and axonal changes. Changes in FA and MD were preceded by VBM in the corpus callosum and corona radiata. Cognitive results correlated with FA changes.ConclusionIn CTX, GM atrophy affected the perfusion patterns. Changes in WM included atrophy, and axonal changes with demyelination. Disconnection of major fiber tracts among different cortical regions may contribute to cognitive impairment.

Appropriate time for post-therapeutic I-131 whole body scan.

Iodine metabolism and kinetics in thyroid carcinoma cells may be different from that in normal thyroid tissue. The optimal time for performing post-therapeutic scans to detect metastatic lesions is still controversial. We retrospectively analyzed the images of 239 patients who received I-131 therapy at our hospital from January 2006 to May 2008. The therapeutic dose ranged from 1.1 GBq (30 mCi) to 7.4 GBq (200 mCi) and the patients received 3 sequential whole body scans on the third to fourth day, fifth to sixth day, and 10th-11th day after I-131 administration. We scored the I-131 avid lesions by visual assessment into 3 grades: 2 = clearly visible; 1 = visible; and 0 = not visible. We also compared the thyroglobulin levels and FDG uptake among the lesions with probably different kinetics of iodine metabolism. In this study, there was a trend of decreasing visualization of lesions in the sequential images. Twenty-eight percent of lymph node metastases, 17% of lung metastases, and 16% of bone metastases were missed on the late images on 10-11th day. On the other hand, only 5% of the remnants were missed. The ratio of early washout was different between remnants and metastatic lesions. The serum thyroglobulin levels and FDG uptake did not correlate with early washout of the I-131 avid lesions. We concluded that earlier imaging is necessary for detection of metastatic lesions.

18F‐FP‐(+)‐DTBZ positron emission tomography detection of monoaminergic deficient network in patients with carbon monoxide related parkinsonism

Although parkinsonism after carbon monoxide (CO) intoxication is well known, neurotransmitter deficient networks that are responsible for the severity of parkinsonism have rarely been systemically evaluated.

Cortical metabolic and nigrostriatal abnormalities associated with clinical stage-specific dementia with Lewy bodies.

Purpose The aims of this study were to investigate the hypometabolic regions of FDG PET compared with the nigrostriatal dopamine pathway abnormalities in TRODAT-1 scan in patients with dementia with Lewy bodies (DLBs) at mild and dementia stages as well as to validate the correlation among networks being constructed with clinical data. Materials and Methods A total of 25 DLB patients were classified into 2 functional groups stratified by the Clinical Dementia Rating (CDR) Scale (CDR 0.5: n = 14, mild stage; CDR 1 or 2: n = 11, dementia stage) compared with 9 age-matched controls. Neuroimaging survey was applied using information derived from FDG PET by performing voxel-based analysis and a semiquantitative 99mTc-TRODAT-1 scan to correlate these results with the cognitive and Unified Parkinson’s Disease Rating Scale. Results Compared with normal database, the patients with mild stage showed hypometabolism in the temporal regions, anterior cingulate cortex, inferior orbital region, thalamus, and caudate nucleus. Although at the dementia stage, more extensive cortical hypometabolism involving occipital region were found. The dopamine transporter levels derived from TRODAT-1 scan had excellent discrimination in diagnosing DLB compared with age-matched normal controls (1.58 [0.2] and 1.84 [0.1], P < 0.01) but without significant differences between mild and dementia stages. The sophisticated cortical-brainstem networks by FDG PET and TRODAT-1 yielded good clinical correlation. Conclusions The networks yielded from FDG PET and TRODAT-1 revealed good correlation with clinical data and that nigrostriatal pathway abnormalities are preceded by typical occipital hypometabolism in mild stage of DLB. Dopamine transporter levels may serve as early diagnostic tool and FDG PET as staging indicator for DLB pathology.