Up-To-Date Magnetic Resonance Imaging Findings for the Diagnosis of Hypothalamic and Pituitary Tumors

Magnetic resonance imaging (MRI) is the preferred imaging technique for the sellar and parasellar regions. In this review article, we report our clinical experience with MRI for hypothalamic and pituitary lesions, such as pituitary adenomas, craniopharyngiomas, Rathke cleft cysts, germinoma, and hypophysitis with reference to the histopathological findings through a review of the literature. Our previous study indicated that three dimensional-spoiled gradient echo sequence is a more suitable sequence for evaluating sellar lesions on postcontrast T1 weighted image (WI). This image demonstrates the defined relationship between the tumor and its surroundings, such as the normal pituitary gland, cavernous sinus, and optic pathway. We demonstrated the characteristic MRI findings of functioning pituitary adenoma. In growth hormone-producing adenoma, signal intensity on T2WI is important to differentiate densely from sparsely granulated somatotroph adenomas. In prolactin-producing pituitary adenomas, distinct hypointense areas in early phase on T2WI, possibly owning to diffuse hemorrhage, indicate pronounced regressions of invasive macroprolactinomas during cabergoline therapy. The two histopathological subtypes, adamantinomatous and squamous papillary craniopharyngioma, differ in genesis. Calcified tumors are mostly adamantinomatous type. On MRI, these lesions have a heterogenous appearance with a solid portion and cystic components. The solid portions and cyst wall enhance heterogeneously. Although cyst fluid of Rathke cleft cysts show variable intensities on MRI, intracystic waxy nodule can be hypointense on T2WI. The enhancing cyst wall may contain the squamous metaplasia. Cystic lesions of the sellar and parasellar areas may be difficult to differentiate on a clinical, imaging, or even histopathological basis

A New Method of Microcatheter Heat-Forming for Cerebral Aneurysmal Coiling Using Stereolithography Three-Dimensional Printed Hollow Vessel Models

[Background] To perform successful coil embolization of cerebral aneurysms, it is crucial to make an appropriately shaped microcatheter tip for an aneurysm and its parent artery. So far, we manually shaped a mandrel by referencing two-dimensional (2D) images of a rotation digital subtraction angiography (DSA) on a computer screen. However, this technique requires a lot of experience, and often involves trial and error. Recently, there have been increasing reports of manual mandrel shaping using a full-scale three-dimensional (3D) model of an aneurysm and its parent artery output by various types of 3D printer. We have further developed this method by producing a hollow model of an aneurysm and its parent artery with a stereolithography 3D printer and inserting a mandrel inside the model to fit and stabilize a microcatheter tip. [Methods] Based on digital imaging and communications in medicine (DICOM) data obtained by rotational DSA, 3D images of an aneurysm and its parent artery were created and converted into standard triangulated language (STL) data. A hollow model was produced by extruding the STL data outward in the normal direction, and then a hole was made at the tip of the aneurysm using these STL data. We output these STL data to a stereolithography 3D printer. After cleaning and sterilizing the model, the mandrel was inserted in the direction of the parent artery through the hole made in the tip of the aneurysm and pushed in, creating the ideal mandrel shape. Twelve cases (14 aneurysms) were included in this study. A microcatheter tip was shaped by this method for patients who were scheduled to undergo coil embolization for an unruptured aneurysm. [Results] In 13 of the 14 aneurysms, the microcatheter was easily guided into the aneurysms in one or two trials, the position of the microcatheter tip in the aneurysm was appropriate, and the stability during coil embolization was high. [Conclusion] Our method differs from the conventional one in that a hollow model made of resin is produced with a stereolithography 3D printer and that the mandrel is shaped by inserting it retrogradely into the hollow model. Using our new method, it will be possible to shape the tip of a microcatheter suitable for safe and stable coil embolization without relying on an operator’s experience

High-grade Glioma Masquerading as a Small Cerebral Hemorrhage: A Case Report

We report a rare case of a high-grade glioma masquerading as a small subcortical hemorrhage. A 71-year-old woman came to a local hospital with sudden right upper extremity numbness. Computed tomography revealed a small subcortical hemorrhage with faint perifocal edema in the left postcentral gyrus. Conservative treatment was initiated, and she was discharged from the hospital with no neurological deficits. Six months later after discharge, she suffered an acute partial seizure of the right upper extremity. Magnetic resonance imaging with gadolinium demonstrated a ring-enhancing mass surrounded by severe perifocal edema in the hemorrhagic scar. We performed complete resection of the tumor, and the histological diagnosis was anaplastic oligodendroglioma. The diagnosis of a high-grade glioma was delayed due to intratumoral hemorrhages mimicking a small subcortical hemorrhage; consequently, we suspected the hemorrhage was induced by cerebral amyloid angiopathy. It may be important to repeat radiological follow up, if necessary, and to maintain clinical observance of possible intracranial neoplasm, even when the hemorrhage is small, particularly when the cause of bleeding is unknown

Invasive Fungal Rhinosinusitis with Orbital Apex Syndrome Leading to Brain Abscess in a Patient with Ulcerative Colitis

We report the case of a 65-year-old male who presented with a 1-week history of right periorbital pain and progressive visual loss. He had a history of ulcerative colitis and was taking oral corticosteroids and mesalazine. Neurological and radiological examination demonstrated a rare case of invasive fungal rhinosinusitis that began with orbital apex syndrome. Initial endoscopic sinus surgery was performed and fungal culture identified Aspergillus fumigatus. Although antifungal treatment was started empirically before the operation, the patient had improved orbital pain but continued to have decreased right vision. Five months after the first surgical procedure, his condition deteriorated, including loss of consciousness, and a right temporal lobe abscess was found and surgically drained. Since then, the patient received antifungal treatment for 4 years without recurrence. Invasive fungal rhinosinusitis with orbital apex syndrome should be treated with long-term postoperative antifungal medication. It should be noted that even in immunosuppressive individuals such as ulcerative colitis, fungal rhinosinusitis with orbital apex syndrome may become severe

A Case of Skull Base Chondrosarcoma with Intraoperative Trigemino-Cardiac Reflex

A 75-year-old female patient presented with a suspected recurrence of a clival chordoma. The tumor was resected using the infratemporal fossa type B and anterior petrosal approach with the help of a neurosurgeon. During cauterization of the trigeminal nerve, the patient developed cardiac arrest for approximately 10 seconds because of the trigemino-cardiac reflex (TCR). After several sternal compressions, there was return of spontaneous circulation. The operation was resumed after the circulatory dynamics stabilized. Subsequently, the surgery was completed with partial resection of the tumor without the recurrence of cardiac arrest. The pathological diagnosis was chondrosarcoma, and postoperative treatment with radiotherapy was started. Stimulation of the sensory branches of the trigeminal nerve induces TCR. There are reports of TCR developing in approximately 10% of skull base surgery cases in the absence of atropine administration. We report a rare case of TCR during the surgical procedure for the treatment of a skull base chondrosarcoma