Impaired Efficiency and Resilience of Structural Network in Spinocerebellar Ataxia Type 3

Background: Recent studies have shown that the patients with spinocerebellar ataxia type 3 (SCA3) may not only have disease involvement in the cerebellum and brainstem but also in the cerebral regions. However, the relations between the widespread degenerated brain regions remains incompletely explored.Methods: In the present study, we investigate the topological properties of the brain networks of SCA3 patients (n = 40) constructed based on the correlation of three-dimensional fractal dimension values. Random and targeted attacks were applied to measure the network resilience of normal and SCA3 groups.Results: The SCA3 networks had significantly smaller clustering coefficients (P < 0.05) and global efficiency (P < 0.05) but larger characteristic path length (P < 0.05) than the normal controls networks, implying loss of small-world features. Furthermore, the SCA3 patients were associated with reduced nodal betweenness (P < 0.001) in the left supplementary motor area, bilateral paracentral lobules, and right thalamus, indicating that the motor control circuit might be compromised.Conclusions: The SCA3 networks were more vulnerable to targeted attacks than the normal controls networks because of the effects of pathological topological organization. The SCA3 revealed a more sparsity and disrupted structural network with decreased values in the largest component size, mean degree, mean density, clustering coefficient, and global efficiency and increased value in characteristic path length. The cortico-cerebral circuits in SCA3 were disrupted and segregated into occipital-parietal (visual-spatial cognition) and frontal-pre-frontal (motor control) clusters. The cerebellum of SCA3 were segregated from cerebellum-temporal-frontal circuits and clustered into a frontal-temporal cluster (cognitive control). Therefore, the disrupted structural network presented in this study might reflect the clinical characteristics of SCA3

Long Term Outcomes and Effects of Surgery on Degenerative Spinal Deformity: A 14-Year National Cohort Study

Degenerative spinal deformity (DSD) has become a prevalent cause of disability and pain among the aging population worldwide. Though surgery has emerged as a promising option for DSD, the natural course, outcomes, and effects of surgery on DSD have remained elusive. This cohort study used a national database to comprehensively follow up patients of DSD for all-cause mortality, respiratory problems, and hip fracture-related hospitalizations. All patients were grouped into an operation or a non-operation group for comparison. An adjustment of demographics, comorbidities, and propensity-score matching was conducted to ameliorate confounders. A Cox regression hazard ratio (HR) model and Kaplan-Meier analysis were also applied. The study comprised 21,810 DSD patients, including 12,544 of the operation group and 9266 of the non-operation group. During the 14 years (total 109,591.2 person-years) of follow-up, the operation group had lower mortality (crude hazard ratio = 0.40), lower respiratory problems (cHR = 0.45), and lower hip fractures (cHR = 0.63) than the non-operation group (all p < 0.001). After adjustment, the risks for mortality and respiratory problems remained lower (adjusted HR = 0.60 and 0.65, both p < 0.001) in the operation than the non-operation group, while hip fractures were indifferent (aHR = 1.08, p > 0.05). Therefore, surgery for DSD is invaluable since it could reduce the risks of mortality and of hospitalization for respiratory problems

Vascular wall imaging in reversible cerebral vasoconstriction syndrome – a 3-T contrast-enhanced MRI study

Abstract Background Limited histopathology studies have suggested that reversible cerebral vasoconstriction syndromes (RCVS) does not present with vascular wall inflammation. Previous vascular imaging studies have had inconsistent vascular wall enhancement findings in RCVS patients. The aim of this study was to determine whether absence of arterial wall pathology on imaging is a universal finding in patients with RCVS. Methods We recruited patients with RCVS from Taipei Veterans General Hospital prospectively from 2010 to 2012, with follow-up until 2017 (n = 48). We analyzed the characteristics of vascular wall enhancement in these patients without comparisons to a control group. All participants received vascular wall imaging by contrasted T1 fluid-attenuated inversion recovery with a 3-T magnetic resonance machine. The vascular wall enhancement was rated as marked, mild or absent. Results Of 48 patients with RCVS, 22 (45.8%) had vascular wall enhancement (5 marked and 17 mild). Demographics, clinical profiles, and cerebral artery flow velocities were similar across patients with versus without vascular wall enhancement, except that patients with vascular wall enhancement had fewer headache attacks than those without (p = 0.04). Follow-up imaging completed in 14 patients (median interval, 7 months) showed reduced enhancement in 9 patients, but persistent enhancement in 5. Conclusion Almost half of our RCVS patients exhibited imaging enhancement of diseased vessels, and it was persistent for approximately a third of those patients with follow-up imaging. Both acute and persistent vascular wall enhancement may be unhelpful for differentiating RCVS from central nervous system vasculitis or subclinical atherosclerosis

The Current Role of 1.5T Non-contrast 3D Time-of-flight Magnetic Resonance Angiography to Detect Intracranial Steno-occlusive Disease

This study was performed to evaluate the role of non-contrast 3D time-of-flight (TOF) magnetic resonance angiography (MRA) to detect and quantify intracranial steno-occlusive disease. Methods: Between April 2004 and January 2006, 45 patients with both 1.5T TOF MRA and digital subtraction angiography (DSA) performed within a 30-day interval were included. We evaluated the following intracranial arterial segments: petrous internal carotid artery (ICA), cavernous ICA, supraclinoid ICA, M1 of middle cerebral artery A1 of anterior cerebral artery P1 of posterior cerebral artery basilar artery and distal vertebral artery. In total, 675 arterial segments were evaluated and categorized as negative, moderate-1 (30–49% stenosis), moderate-2 (50–69%), severe (70–99% stenosis, including gap sign on MRA), and occlusion. Results: The sensitivity and specificity of TOF MRA for >29% stenosis and >49% stenosis were 94%, 96% and 95%, 96%, respectively; while sensitivity and specificity for occlusion lesions were both 100%. However, 44 segments (37% of diseased segments) were overestimated by MRA, including 20 false-positive stenoses (which occurred in 10 [22%] patients) and 24 overestimated stenosis degree. The gap sign as severe stenosis only showed about 21% sensitivity and 41% specificity. Seven lesions were underestimated by MRA: three arterial segments were out of the field of MRA examination, and four were moderate-1 stenosis on DSA. Conclusion: TOF MRA has high sensitivity and specificity in detecting all categories of stenosis degree and occlusion. However, it tends to overestimate lesions. Therefore, MRA can be considered as a screening study. Confirmation with other studies is recommended in doubtful cases

Association between proton magnetic resonance spectroscopy measurements and CAG repeat number in patients with spinocerebellar ataxias 2, 3, or 6.

The aim of this study was to correlate magnetic resonance spectroscopy (MRS) measurements, including that for the N-acetyl aspartate (NAA)/creatine (Cr) ratio in the vermis (denoted V-NAA), right cerebellar hemisphere (R-NAA), and left (L-NAA) cerebellar hemisphere, with the clinical scale for the assessment and rating of ataxia (SARA) score for patients with spinocerebellar ataxia (SCA) types 2, 3, and 6. A total of 24 patients with SCA2, 48 with SCA3, and 16 with SCA6 were recruited; 12 patients with SCA2, 43 with SCA3, and 8 with SCA6 underwent detailed magnetic resonance neuroimaging. Forty-four healthy, age-matched individuals without history of neurologic disease served as control subjects. V-NAA and patient age were used to calculate the predicted age at which a patient with SCA2 or SCA3 would reach an onset V-NAA value. Results showed the following: the NAA/Cr ratio decreased with increasing age in patients with SCA but not in control subjects; the SARA score increased progressively with age and duration of illness; V-NAA showed a better correlation with SARA score than R-NAA in patients with SCA2 or SCA3; the ratio of age to V-NAA correlated well with CAG repeat number; the retrospectively predicted age of onset for SCA2 and SCA3 was consistent with patient-reported age of onset; R-NAA showed a better correlation with SARA score than V-NAA in patients with SCA6; V-NAA and R-NAA correlated with clinical severity (SARA score) in patients with SCA. The correlation between CAG repeat number and age could be expressed as a simple linear function, which might explain previous observations claiming that the greater the CAG repeat number, the earlier the onset of illness and the faster the disease progression. These findings support the use of MRS values to predict age of disease onset and to retrospectively evaluate the actual age of disease onset in SCA

High-resolution Computed Tomography in the Diagnosis of Otosclerosis in Taiwan

Otosclerosis is rare in Asians, and the clinical role of imaging remains controversial. We sought to clarify the tomographic findings of otosclerosis in Taiwanese patients and determine the value and necessity of high-resolution computed tomography (HRCT) of the temporal bone in diagnosing the disease in Taiwan. Methods: This retrospective study enrolled 22 patients (24 ears) with clinically, surgically and pathologically confirmed otosclerosis. All subjects underwent HRCT of the temporal bone; the images were then reviewed at workstations. The control group consisted of 15 patients. Results: HRCT was positive in 46% of the clinically, surgically and pathologically confirmed otosclerotic ears. Patients with a positive imaging study had a smaller preoperative air–bone gap and a significantly shorter duration of the disease. The duration of the disease also tended to be greater in patients with a larger preoperative air–bone gap. Conclusion: HRCT has high specificity (100%) but low sensitivity (46%) for the diagnosis of otosclerosis in Taiwanese patients despite progress in radiology. The low image positive rate we found, compared with that in Western literature, may stem from a greater percentage of inactive otosclerosis. [J Chin Med Assoc 2009;72(10):527–532