An 87-year-old woman presented with an atypical case of acute subdural hematoma (ASDH) manifesting as disturbance of consciousness and left hemiparesis. Computed tomography revealed a high density lentiform lesion in the right convexity, which was thought to be acute epidural hematoma preoperatively. Emergent decompressive craniotomy revealed an encapsulated solid fresh clot in the subdural space and a bleeding small cortical artery under the clot. The arachnoid membrane and the brain parenchyma were intact, and no other abnormal feature such as aneurysm or arteriovenous malformation was observed. The encapsulated ASDH was removed en bloc and the patient fully recovered. Histological examination confirmed that both the outer thicker and the inner membrane were fibrinous single structures without vasculature. The red blood cells constituting the clot in the capsule maintained their cell structure. The reported pathological mechanisms of lentiform ASDH are adhesion of the arachnoid membrane and the dura mater or intracapsular bleeding from sinusoidal vessels in the outer membrane of the chronic subdural hematoma. However, in our case, the arachnoid membrane had not adhered to the dura mater and the capsule was a fibrinous single structural membrane without vasculature, which probably resulted from a previous hematoma due to initial bleeding from the cortical artery. The possible mechanism in our case was that the re-bleeding dissected and flowed into the fibrinous single structural membrane, resulting in formation of the lentiform ASDH.

An 8-year-old boy presenting with a transient weakness of the left extremities had a rare association of moyamoya disease and persistent primitive hypoglossal artery (PPHA). Digital subtraction angiography demonstrated intracranial moyamoya vessels and a PPHA on the right side. There was collateral blood flow from the posterior circulation to the anterior circulation, with the PPHA functioning as a blood supplier vessel. The patient underwent multiple burr hole formation, and neovascularization via the burr holes was observed on follow-up angiography. In this case, blood flow into the posterior circulation via the PPHA, which served as the collateral vessel to the moyamoya phenomenon, may have disturbed the spontaneous closure of the PPHA. Thus, this case serves as a basis for studying important pathogenic and embryological processes that contribute to the development of these vascular abnormalities.

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The diagnostic value of single photon-emission computed tomography (SPECT) has been assessed using arbitrarily determined sensitivity and specificity cut-off values. The diagnostic accuracy of thallium-201 (Tl-201) SPECT and technetium-99m methoxyisobutylisonitrile (Tc-MIBI) SPECT were compared for patients with primary glioma using receiver operating characteristic (ROC) analysis. The study population included 59 patients with gliomas. Tl and Tc-MIBI SPECT images were obtained using a multi-detector SPECT machine 15 min (early) and 3 hours (delayed) after intravenous injection of 74 MBq of Tl-chloride or 740 MBq of Tc-MIBI. The regions of interest were set on the tumor and contralateral normal white matter and tumor : normal ratios were calculated. The area z-score (A(z)) values were calculated from the areas under the ROC curves. All A(z) values were high and no statistical difference was observed between the two modalities. Both Tl and Tc-MIBI SPECT are useful imaging modalities for the evaluation of glioma malignancy.