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BACKGROUND In patients with sellar or parasellar tumors, it is crucial to evaluate visual field impairment in the preoperative stage and to predict visual field improvement after the surgery. The purpose of this study was to investigate the associations of diffusion tensor imaging (DTI) and neurite orientation dispersion and density imaging (NODDI) parameters in the optic radiations with preoperative and postoperative visual field impairment. METHODS This prospective study included 81 participants with sellar or parasellar tumors. Multishell diffusion imaging and a visual field impairment score (VFIS) were acquired before and after the surgery. The multishell diffusion-weighted imaging was acquired to measure the neurite density and neurite orientation dispersion, as well as the diffusivity. DTI parameters were fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity, and radial diffusivity (RD). NODDI provided intracellular volume fraction (Vic), the orientation dispersion index, and isotropic volume fraction (Viso). The associations of DTI and NODDI parameters in the optic radiations with VFIS were investigated, adjusting for age, tumor height, and symptom duration. RESULTS Among 162 optic radiations, 117 were functionally impaired in the preoperative stage. FA and Vic had significant negative correlations, whereas MD and RD had significant positive correlations with the VFIS (all P < 0.001). In the preoperative stage, lower FA (P = 0.001; odds ratio = 0.750) and Vic (P = 0.003; OR = 0.827) and higher MD (P = 0.007; OR = 1.244) and RD (P < 0.001; OR = 1.361) were significantly associated with the presence of visual field impairment. For the degree of postoperative improvement, preoperative lower Vic (P = 0.034; OR = 0.910) and higher MD (P = 0.037; OR = 1.103) and RD (P = 0.047; OR = 1.090) were significantly associated with more postoperative improvement. CONCLUSIONS DTI and NODDI parameters in the optic radiations were correlated with VFIS and associated with preoperative visual field impairments and postoperative improvement. It may help in predicting visual field improvement after the surgery in patients with sellar or parasellar tumors.

ObjectivesTo investigate the relationships of serum albumin with in vivo Alzheimer disease (AD) pathologies, including cerebral β-amyloid (Aβ) protein deposition, neurodegeneration of AD-signature regions, and cerebral white matter hyperintensities (WMH), in the human brain.MethodsA total of 396 older adults without dementia underwent comprehensive clinical assessments, measurement of serum albumin level, and multimodal brain imaging, including [11C] Pittsburgh compound B-PET,18F-fluorodeoxyglucose-PET, and MRI. Serum albumin was categorized as follows: 4.5 g/dL (high albumin; used as a reference category). Aβ positivity, AD-signature region cerebral glucose metabolism (AD-CM), AD-signature region cortical thickness (AD-CT), and WMH volume were used as outcome measures.ResultsSerum albumin level (as a continuous variable) was inversely associated with Aβ deposition and Aβ positivity. The low albumin group showed a significantly higher Aβ positivity rate compared to the high albumin group (odds ratio 3.40, 95% confidence interval 1.67–6.92,p= 0.001), while the middle albumin group showed no difference (odds ratio 1.74, 95% confidence interval 0.80–3.77,p= 0.162). Neither serum albumin level (as a continuous variable) nor albumin categories were related to AD-CM, AD-CT, or WMH volume.ConclusionsLow serum albumin may increase the risk of AD dementia by elevating amyloid accumulation. In terms of AD prevention, more attention needs to be paid to avoid a low serum albumin level, even within the clinical normal range, by clinicians.

There has been controversy as to whether gadobutrol, one of the widely used macrocyclic gadolinium-based contrast agents, can lead to gadolinium retention after serial injections. Our aim was to validate whether serial administrations of gadobutrol can cause signal increase in the dentate nucleus (DN) and globus pallidus (GP) on unenhanced T1-weighted magnetic resonance (MR) images due to gadolinium retention.A total of 189 patients who had undergone at least 2 contrast-enhanced MR scans using only gadobutrol between August 2009 and August 2016 were retrospectively included. The DN-to-pons and GP-to-thalamus signal intensity (SI) ratio differences on unenhanced T1-weighted MR images were calculated by subtracting the SI ratios at the first MR images from those at the last MR images. One-sample t tests were used to evaluate whether the SI ratio differences differed from 0. Linear regression and Pearson correlations were performed to assess correlations between SI ratio differences and various confounding variables, including the number of MR scans, mean time interval between MR scans, age, sex, history of radiation therapy or chemotherapy, and renal and liver functions.Patients underwent a mean of 5.9 ± 6.3 contrast-enhanced MR scans with a mean interval of 42.8 ± 49.5 weeks between the scans. Sixty-three patients underwent 6 or more MR scans, whereas 126 patients underwent fewer than 6 MR scans. Neither the DN-to-pons SI nor the GP-to-thalamus SI ratio differences differed significantly from 0, with mean values of -0.012 ± 0.115 (P = 0.148) and 0.012 ± 0.111 (P = 0.126), respectively.Serial administrations of gadobutrol did not result in signal increases in the DN or GP on unenhanced T1-weighted MR images due to gadolinium retention.

Background and Purpose— The purpose of this study was to evaluate whether bright vessel appearance on arterial spin labeling (ASL) MRI can help localize arterial occlusion sites in patients with acute ischemic stroke. Methods— Patients who underwent MRI for suspected acute ischemic stroke, as identified by an area of restricted diffusion, were included. All images were visually analyzed for the presence or absence of (1) arterial occlusion on time-of-flight MR angiography, (2) bright vessel appearance on ASL images, and (3) susceptibility vessel sign. McNemar 2-tailed test was used to compare the sensitivities of ASL and susceptibility-weighted imaging for the detection of arterial occlusion, using MR angiography as the reference standard. Results— ASL bright vessel appearance was significantly more common in the group with occlusion than in the group without occlusion (94% [33 of 35] versus 21% [17 of 82], respectively; P P =0.002). In cases with negative MR angiography, the bright vessel appearance helped identify more additional arterial occlusions than the susceptibility vessel sign (21% [17 of 82] versus 10% [8 of 82], respectively; P =0.012). Conclusions— The bright vessel appearance on ASL imaging can provide an important diagnostic clue for the detection and localization of arterial occlusion sites in patients with acute ischemic stroke.

Cerebral venous thrombosis is a potentially lethal disease. Early diagnosis is essential to improve its prognosis. However, its early diagnosis based on conventional imaging modalities remains a challenge in clinical settings. The purpose of this study was to evaluate whether bright sinus appearance on arterial spin-labeling perfusion-weighted image (ASL-PWI) could help identify cerebral venous thrombosis. ASL-PWI of 13 patients who were confirmed as cerebral venous thrombosis based on neurologic symptoms and computed tomography (CT) or magnetic resonance (MR) venography (with/without cerebral angiography) were retrospectively analyzed for the presence or absence of the following: bright signal in dural sinus termed “bright sinus appearance”; and hypoperfusion in brain parenchyma drained by thrombosed sinus. In addition, conventional MR findings, including susceptibility vessel sign, empty delta sign, and atypical distribution against arterial territory, were also analyzed. Bright sinus appearance on ASL-PWI was found in all (100%) 13 patients. In addition, 10 (77%) patients showed hypoperfusion in the brain parenchyma drained by thrombosed sinus on ASL-PWI. Susceptibility vessel sign and empty delta sign were revealed in 11 (85%) and 7 (54%) patients, respectively. Atypical distribution against arterial territory was seen in 5 (50%) of the 10 patients with parenchymal abnormality on conventional MR sequences. Therefore, the bright sinus appearance had higher sensitivities for identifying cerebral venous thrombosis than the susceptibility vessel sign, empty delta sign, and atypical distribution against arterial territory (with differences of 15%; P = .500, 46%; P = .031, and 50%; P = .031, respectively). Bright sinus appearance on ASL-PWI can provide important diagnostic clue for identifying cerebral venous thrombosis. Therefore, this technique may have the potential to be used as a noninvasive diagnostic tool to identify the cerebral venous thrombosis.