Purpose. To investigate the pathological change of the glymphatic system in idiopathic normal pressure hydrocephalus (iNPH) using diffusion tensor imaging (DTI) analysis. Materials and Methods. 24 right-handed patients were referred to our hydrocephalus clinic for assessment of ventriculomegaly and gait impairment. 12 of 24 were diagnosed as pseudo-iNPH (piNPH) based on assessment by a neurologist. Diffusivity maps in the direction of the x-axis (right-to-left) (Dx), y-axis (anterior-to-posterior) (Dy), and z-axis (inferior-to-superior) (Dz) were computed. The diffusion map was coregistered to International Consortium for Brain Mapping (ICBM) DTI-81 atlas. The analysis along the perivascular space (ALPS) index was defined as mean (Dxpro, Dypro)/mean (Dypro, Dzasc), where Dxpro and Dxasc are Dx values in the projection and association fiber areas, respectively. Evans index and callosal angle were also assessed on each case. Results. ALPS indexes of the control, piNPH, and iNPH cases were 1.18 ± 0.08, 1.08 ± 0.03, and 0.94 ± 0.06, respectively, and there were significant differences among the groups (control vs. piNPH, P = 0.003; control vs. iNPH P < 0.001; piNPH vs. iNPH, P < 0.001). Area under curve (AUC) was 0.92, 1.00, and 1.00 on control vs. piNPH, control vs. iNPH, and piNPH vs. iNPH on ROC analysis. Between piNPH and NPH, ALPS index has higher diagnostic performance than Evans index and callosal angle (AUC = 1.00 vs. 0.84, P = 0.028; AUC = 1.00 vs. 0.74, P = 0.016). Conclusion. Atlas-based ALPS index using the DTI method differentiated among iNPH, piNPH, and controls clearly.

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BACKGROUND AND PURPOSE:Glioblastoma is a common primary brain tumor with a poor but variable prognosis. Our aim was to investigate the feasibility of MR perfusion imaging by using arterial spin-labeling for determining the prognosis of patients with glioblastoma.

Background and Purpose A substantial portion of clinically diagnosed TIA cases is imaging-negative. The purpose of the current study is to determine if arterial spin-labeling (ASL) is helpful in detecting perfusion abnormalities in patients presenting clinically with TIA. Materials and Methods Pseudo-continuous ASL with 3D background suppressed gradient and spin echo (GRASE) was acquired on 49 patients suspected of TIA within 24 hours of symptom onset. All patients were free of prior stroke history and had no lesion-specific findings on general MR, DWI and MRA sequences. The calculated ASL CBF maps were scored from 1 to 3 based on the presence and severity of perfusion disturbance by three independent observers blinded to patient history. An age-matched cohort of 36 patients diagnosed with no cerebrovascular events was evaluated as a control. Inter-observer agreement was assessed using Kendall concordance test. Results Scoring of perfusion abnormalities on ASL scans of TIA cohort was highly concordant among the 3 observers (w=0.812). The sensitivity and specificity of ASL in diagnosing perfusion abnormalities in TIA was 55.8% and 90.7%, respectively. In 93.3% (70 out of 75) of the ASL CBF map readings with positive scores (≥2), the brain regions where perfusion abnormalities were identified by 3 observers matched with the neurological deficits at TIA onset. Conclusion In this preliminary study, ASL showed promise in detecting perfusion abnormalities that correlated with clinically diagnosed TIA in patients with otherwise normal neuro-imaging.

Purpose: Differentiating WHO grade I–III of meningioma by non-invasive imaging is challenging. This study investigated the potential of MR arterial spin labeling (ASL) to establish tumor grade in meningioma patients. Material and methods: Pseudo-continuous ASL with 3D background suppressed gradient and spin echo (GRASE) was acquired on 54 patients with newly diagnosed or recurrent intracranial meningioma. Perfusion patterns characterized in CBF color maps were independently evaluated by three neuroradiologists blinded to patient history, and correlated with tumor grade from histo-pathological review. Results: Three perfusion patterns could be discerned by visual evaluation of CBF maps. Pattern 1 consisted of homogeneous hyper-perfusion of the entire tumor; pattern 2 demonstrated heterogeneous hyper-perfusion; pattern 3 showed no substantial hyper-perfusion. Evaluation of the perfusion patterns was highly concordant among the three readers (Kendall W = 0.9458, P < 0.0001). Pattern 1 was associated with WHO Grade I meningioma of (P < 0.0001). Patterns 2 and 3 were predictive of WHO Grade II and III meningioma (P < 0.0001), with an odds ratio (OR, versus pattern 1) of 49.6 (P < 0.01) in a univariate analysis, and an OR of 186.4 (P < 0.01) in a multivariate analysis. Conclusion: Qualitative evaluation of ASL CBF maps can help differentiate benign (WHO Grade I) from higher grade (WHO Grade II and III) intracranial meningiomas, potentially impacting therapeutic strategy.

Most patients with large pituitary tumors do not exhibit hyperprolactinemia as a result of pituitary lactotroph disinhibition (stalk effect). Studies have demonstrated that increased intrasellar pressure is associated with both "stalk effect" hyperprolactinemia and pituitary insufficiency. Our primary hypothesis was that, despite continued disinhibition, lactotroph failure is responsible for normoprolactinemia in patients with large macroadenomas. As a corollary, we proposed that the hyperprolactinemia phase, which presumably would precede the insufficiency/normoprolactinemic state, would more likely be discovered in premenopausal females and go unnoticed in males. Prospective, consecutive surgical series of 98 patients of clinically nonfunctional pituitary adenomas. Lactotroph insufficiency was inferred by the coexistence of insufficiency in another pituitary axis. The existence of pre-operative lactotroph disinhibition was inferred based on comparison of pre- versus post-operative prolactin levels. 87 % of patients with tumor size >20 mm and normoprolactinemia had pituitary insufficiency. Pre-operative prolactin in patients with pituitary insufficiency were lower than those with intact pituitary function. Prolactin levels dropped in nearly all patients, including patients with normoprolactinemia pre-operatively. Premenopausal women had smaller tumors and higher pre-operative prolactin levels compared to males. No premenopausal female exhibited evidence of pituitary insufficiency. Our study provides suggestive evidence that the "stalk effect" pathophysiology is the norm rather than the exception, and that the finding of normoprolactinemia in a patient with a large macroadenoma is likely a consequence of lactotroph insufficiency. In males, the hyperprolactinemia window is more likely to be missed clinically due to an absence of prolactin-related symptoms.

Intracochlear schwannoma is a rare, treatable, cause of unilateral hearing loss. Due to the small size, position, and variable clinical and imaging features, diagnosis presents a significant challenge and is often delayed. We present a case of a patient with an intracochlear schwannoma presenting as a diffuse enhancement of the cochlea, mimicking an infectious or inflammatory process. The absence of focal nodularity in this lesion on multiple high-resolution MRI examinations led to a delay of over 3 years from the patient’s initial presentation to surgical diagnosis. Clinical history and examination, imaging features, pathologic findings, and surgical management options are described.

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