The excessive accumulation of iron in deep gray structures is an important pathological characteristic in patients with Alzheimer's disease (AD). Quantitative susceptibility mapping (QSM) is more specific than other imaging-based iron measurement modalities and allows noninvasive assessment of tissue magnetic susceptibility, which has been shown to correlate well with brain iron levels. This study aimed to investigate the correlations between the magnetic susceptibility values of deep gray matter nuclei and the cognitive functions assessed by mini-mental state examination (MMSE) and Montreal cognitive assessment (MoCA) in patients with mild and moderate AD. Thirty subjects with mild and moderate AD and 30 age- and sex-matched healthy controls were scanned with a 3.0 T magnetic resonance imaging (MRI) scanner. The magnetic susceptibilities of the regions of interest (ROIs), including caudate nucleus (Cd), putamen (Pt), globus pallidus (Gp), thalamus (Th), red nucleus (Rn), substantia nigra (Sn), and dentate nucleus (Dn), were quantified by QSM. We found that the susceptibility values of the bilateral Cd and Pt were significantly higher in AD patients than the controls ( P < 0.05). In contrast, bilateral Rn had significantly lower susceptibility values in AD than the controls. Regardless of gender and age, the increase of magnetic susceptibility in the left Cd was significantly correlated with the decrease of MMSE scores and MoCA scores ( P < 0.05). Our study indicated that magnetic susceptibility value of left Cd could be potentially used as a biomarker of disease severity in mild and moderate AD.

Objectives: Computed tomography (CT) is an important technique for evaluating the condition and prognosis of patients with thymomas, and it provides guidance regarding treatment strategies. However, the correlation between CT imaging features, described using standard report terms, and clinical characteristics, Masaoka–Koga stages, and World Health Organization (WHO) classifications of patients with thymomas has not been described in detail nor has risk factor analysis been conducted.Methods: Overall, 159 patients with thymomas who underwent preoperative contrast-enhanced CT between September 2011 and December 2018 were retrospectively reviewed. We assessed the clinical information, CT imaging features, and pathological findings for each patient. A total of 89 patients were specially used to evaluate postoperative recurrence or metastasis between September 2011 and December 2015 to obtain an appropriate observation period. The relationship between CT imaging features and clinical characteristics, Masaoka–Koga stage, and WHO histological classification were analyzed, and related risk factors based on CT imaging features were identified.Results: CT imaging features did not significantly differ based on sex or age. Some imaging features demonstrated significant differences between the groups with and without related clinical characteristics. Contour (odds ratio [OR] = 3.711, P = 0.005), abutment ≥50% (OR = 4.277, P = 0.02), and adjacent lung abnormalities (OR = 3.916 P = 0.031) were independent risk factors for relapse or metastasis. Among all imaging features, there were significant differences between stage I/II and III/IV lesions in tumor size, calcification, infiltration of surrounding fat, vascular invasion, pleural nodules, elevated hemidiaphragm, and pulmonary nodules. Tumor size (odds ratio = 1.261, P = 0.014), vascular invasion (OR = 2.526, P = 0.023), pleural nodules (OR = 2.22, P = 0.048), and pulmonary nodules (OR = 3.106, P = 0.006) were identified as independent risk factors. Tumor size, contour, internal density, infiltration of surrounding fat, and pleural effusion significantly differed between low- and high-risk thymomas. Tumor size (OR = 1.183, P = 0.048), contour (OR = 2.288, P = 0.003), internal density (OR = 2.192, P = 0.024), and infiltration of surrounding fat (OR = 2.811 P = 0.005) were independent risk factors.Conclusions: Some CT imaging features demonstrated significant correlations with clinical characteristics, Masaoka–Koga clinical stages, and WHO histological classifications in patients with thymomas. Familiarity with CT features identified as independent risk factors for these related clinical characteristics can facilitate preoperative evaluation and treatment management for the patients with thymoma.

Purpose: Bell’s palsy refers to acute idiopathic unilateral facial nerve palsy. It is a common disorder of the main motor pathway to the facial muscles. This study aimed to investigate the abnormal fraction amplitude of low frequency fluctuation (fALFF) of the brain in patients with early left and right Bell’s palsy.Materials and Methods: Sixty-seven patients (left 33, right 34) and 37 age- and sex-matched healthy controls underwent resting-state functional magnetic resonance imaging (R-fMRI) examination. The fALFF values were measured from all subjects and were compared among the left palsy, right palsy, and control groups. Then, correlations between the Toronto Facial Grading System (TFGS) scores of the patients and the fALFF values of abnormal brain regions were analyzed.Results: Significant group differences in fALFF values among the three groups were observed mainly in the cerebral cortical, subcortical, and deep gray matter regions. Compared with the right Bell’s palsy group, the left Bell’s palsy group showed significantly decreased fALFF values in the left temporal pole of the superior temporal gyrus (TPOsup), right supramarginal, left and right middle cingulate cortex (MCC), left superior frontal gyrus (SFG), and left precentral gyrus (PreCG), and increased fALFF values were observed in the right SFG and PreCG. Furthermore, altered fALFF values correlated positively with the TFGS scores in the left superior TPO, bilateral MCC, and right PreCG, and correlated negatively with the TFGS scores in the right SFG of the left Bell’s palsy group. Altered fALFF values correlated positively with the TFGS scores in the bilateral MCC and right PreCG and correlated negatively with the TFGS scores in the left superior TPO and SFG of the right Bell’s palsy group.Conclusion: Regulatory mechanisms seem to differ between patients with left and right early Bell’s palsy. The severity of the disease is associated with these functional alterations.

Background and PurposeDiagnosing cervical artery dissection (CAD) is still a challenge based on the current radiographic criteria. This study aimed to assess the value of three-dimensional high-resolution magnetic resonance imaging (3D HRMRI) in the detection of the signs of CAD and its diagnosis.Materials and MethodsPatients with CAD from January 2016 to January 2021 were recruited from our 3D HRMRI database. The signs of dissection (intramural hematomas, intimal flap, double lumen), length and location of the dissection, thickness of the intramural hematoma, intraluminal thrombus, and percentage of dilation of the outer contour of the dissection on 3D HRMRI were assessed.ResultsFourteen patients with 16 CADs, including 12 carotid CADs and 4 vertebral CADs, were finally diagnosed in this study. On 3D HRMRI, intramural hematomas were detected in 13/16 (81.3%) lesions with high sensitivity (100%) and high specificity (100%). Intimal flaps were found in 9/16 (56.3%) lesions with moderate sensitivity (64.3%) and high specificity (88.9%). Double lumen signs were observed in 4/16 (25.0%) lesions with high sensitivity (80.0%) and high specificity (100%). In addition, concomitant intraluminal thrombus were detected in 4/16 (25.0%) lesions with high sensitivity (80.0%) and high specificity (100%). The mean length of dissection was (25.1 ± 13.7) mm. The mean thickness of the intramural hematoma was (4.3 ± 2.3) mm. The mean percentage of dilation for the outer contour of the dissection was (151.3 ± 28.6)%.ConclusionThe 3D HRMRI enables detection of the dissecting signs, such as intramural hematoma, intimal flap, double lumen, and intraluminal thrombus with high sensitivity and specificity, suggesting a useful, and non-invasive tool for definitively diagnosing CAD.

Background: Bell's palsy is defined as idiopathic unilateral facial nerve palsy. Early Bell's palsy is characterized by emerging asymmetric motor conduction of the facial nerve and obvious imbalance of facial muscle movement, which can result in a substantial psychological impact on patients and trigger brain cortical functional reorganization. However, the differences between the brain functional alterations were driven by right or left facial nerve efferent dysfunction in patients with early Bell's palsy are not fully understood. The neuroimage study in patients with different-sided Bell's palsy in the early stage will help to understand the different mechanisms involved in functional integration driven by unilateral facial efferent nerve dysfunction and to provide the theoretical foundation for the choice of suitable treatment strategy. Methods: Sixty-seven patients and 37 age-and sex-matched healthy controls were recruited to undergo resting-state functional magnetic resonance imaging (R-fMRI). Regional brain activity was analyzed by comparing the fractional amplitude of low-frequency fluctuations (fALFF) between right palsy and healthy control, left palsy and healthy control, and right and left palsy groups. The altered brain regions were further selected as seeds in subsequent functional connectivity (FC) analysis, and the correlations between the Toronto Facial Grading System (TFGS) scores and the connectivity alterations were also analyzed. Results: The right and left Bell's palsy groups showed fALFF alterations compared with the healthy control group, and several brain regions with different fALFF values between the right and left palsy groups were identified. In the right palsy group, overall interregional FC increased in the right supramarginal gyrus (SMG), bilateral superior frontal gyrus (SFG), and left precentral gyrus (PreCG), compared with the left palsy group. Furthermore, the brain region pairs with higher FC in the right palsy group were left temporal pole of the superior temporal gyrus (TPOsup) and right SMG, left TPOsup and middle cingulate cortex (MCC), left TPOsup and left PreCG, right SMG and SFG, MCC and left PreCG, left and right SFG, and right SFG and left PreCG. In the right palsy group, the left TPOsup and PreCG showed a negative correlation with the TFGS score, while the right SFG and left PreCG showed a positive correlation with the TFGS scores. In the left palsy group, the left TPOsup and right SMG, and the right SMG and SFG region pairs showed a negative correlation with the TFGS score. Conclusions: The fALFF and FC analyses revealed the remodeling of different brain functional networks driven by right or left facial nerve efferent dysfunction in patients with early Bell's palsy. The reintegration mechanisms differed between patients with right and left Bell's palsy. Additionally, the severity of the disease 428 Han et al. Difference in fMRI alterations between bilateral Bell's palsy