Jusuke Ito

Diffusion-weighted echo-planar MR imaging in differential diagnosis of brain tumors and tumor-like conditions.

Abstract. We assess diffusion-weighted MR images in the differential diagnosis of intracranial brain tumors and tumor-like conditions. Heavily diffusion-weighted (b = 1100 or 1200 s/mm2) axial images were obtained with single-shot echo-planar technique in 93 patients with pathologically confirmed various intracranial tumors and tumor-like conditions with diffusion gradient perpendicular to the images. We compared signal intensity of the lesions with those of gray and white matter, and cerebrospinal fluid (CSF). In 29 cases (31.1 %) the lesions were isointense to gray and/or white matter. However, 5 cases (5.4 %) showed extremely increased signal intensity: two epidermoid cysts; two chordomas; and one brain abscess. The entire portion of a tumor was markedly hyperintense in 10 cases (10.8 %): four malignant lymphomas; four medulloblastomas; one germinoma; and one pineoblastoma. A CSF-like hypointense signal was seen in many cystic tumors, and cystic or necrotic portions of tumors. A neurosarcoid granulation was the only solid lesion showing characteristically a hypointense signal like CSF. The combination of markedly hyperintense and hypointense signals was seen generally in hemorrhagic tumors. Diffusion-weighted echo-planar MR imaging is useful in the differential diagnosis of brain tumors and tumor-like conditions, and suggests specific histological diagnosis in some cases.

Treatment of Moyamoya Disease by Temporal Muscle Graft Encephalo-Myo-Synangiosis’

10 young patients from 7 to 16 years of age with moyamoya disease were treated by temporal muscle graft (encephalo-myo-synangiosis: EMS) for the purpose of increasing extracranial and intracranial collateral circulation. Ischemic cerebrovascular symptoms and signs were encountered in all of them without intracranial hemorrhage. The patients were observed for 6-26 months after the first operation. Transient ischemic attacks disappeared in 4 out of 7 patients, and improved in frequency and duration in the remaining 3. Paresis of the limbs disappeared in 1 patient and improved in 2. In 2 patients, facial palsy disappeared and dysarthria improved as well. Ataxia disappeared in 2 patients, and involuntary movement of the extremities disappeared in 2. There were no ineffective cases clinically. In postoperative carotid angiography, the middle cerebral arteries were visualized clearly to the peripheral portion mainly via the thickened deep temporal arteries, and the abnormal vascular networks in the region of the basal ganglia reduced in size in most of patients. Improvements in intelligence quotient, electroencephalogram and cerebral blood flow were also obtained in several patients, respectively. EMS seemed to be an effective surgical treatment in young patients with moyamoya disease who suffered from cerebral ischemic symptoms.

MRI of enlarged endolymphatic sacs in the large vestibular aqueduct syndrome

Abstract We studied ten inner ears of five patients with a bilateral large vestibular aqueduct syndrome, using CT and MRI. Although the large vestibular aqueduct varied in size, a markedly dilated endolymphatic sac extending to the sigmoid sinus was demonstrated bilaterally on MRI in all patients. The cause of hearing loss in this syndrome is unclear. However, it is suggested that reflux of the protein-rich, hyperosmolar endolymph from the enlarged endolymphatic sac (EES) into the cochlea through a widely patent endolymphatic duct may damage the neuroepithelium. CT density and spin-echo MRI signal intensity of the endolymph in EES were markedly higher than those of CSF in eight inner ears of four patients. Increased density and high signal may indicate protein-rich, hyperosmolar endolymph. In some patients with sensorineural hearing loss and EES, the vestibular aqueduct may not appear dilated on CT. MRI is therefore necessary for correct diagnosis of this syndrome, which should more correctly be termed “large endolymphatic duct and sac syndrome”. Prominent EES may predict poor prognosis in this syndrome.

Fenestration of the middle cerebral artery.

Three cases of angiographically demonstrated fenestration of the middle cerebral artery are reported. The incidence of demonstration of fenestration of the middle cerebral artery by angiography is 0.26%. Its clinical significance is discussed briefly.SummaryThree cases of angiographically demonstrated fenestration of the middle cerebral artery are reported. The incidence of demonstration of fenestration of the middle cerebral artery by angiography is 0.26%. Its clinical significance is discussed briefly.

Imaging of calvarial eosinophil granuloma

Abstract We reviewed the imaging of four pathologically proven calvarial eosinophil granulomas. The diameter of the lesions ranged from 13 to 40 mm; three were biconvex, but the other had a collar-stud appearance. Two lesions were in the frontal and two in the parietal bone. On bone-window CT, a bevelled edge was seen in three cases and button sequestration in one, but no sclerotic rim was shown. Although one lesion had a low-density area, the lesions were slightly denser than grey matter. They were isointense with grey or white matter on T1-weighted MRI and gave heterogeneous high signal on proton-density and T2-weighted images. All enhanced markedly, with a less strongly enhancing portion within them. A tail of dural enhancement and reactive change in the overlying galea or temporal muscle were seen in all cases.

The clinical significance of follow-up sonography in the detection of cervical lymph node metastases in patients with stage i or ii squamous cell carcinoma of the tongue

OBJECTIVE We sought to assess the reliability of repeated sonography in the detection of cervical lymph node metastases at the earliest stage during a follow-up period in patients with stage I or stage II carcinoma of the tongue. STUDY DESIGN Eighteen consecutive patients with stage I or II squamous cell carcinoma of the tongue were included. When possible, every patient was examined with sonography approximately every 2 weeks during the follow-up period. RESULTS With repeated sonography on 18 patients, 7 metastatic nodes of 7 patients (39%) meeting our criteria were found. With the use of computed tomography, we diagnosed 10 nodes (including the 7 nodes observed with sonography) in these 7 patients as metastatic. A histopathologic examination revealed that 12 nodes in the same 7 patients had metastatic foci. For sonography, the sensitivity per node was 58%, whereas that of computed tomography was 83%. CONCLUSIONS Follow-up sonography enabled the detection of all patients who had subsequent subclinical lymph node metastases. However, the sensitivity of sonography in the detection of smaller metastatic nodes was lower than that of computed tomography.

Detectability of anterior displacement of the articular disk in the temporomandibular joint on helical computed tomographyThe value of open mouth position

OBJECTIVE The purpose of this study was to establish the diagnostic reliability of anterior displacement of the articular disk in the temporomandibular joint on helical computed tomography. STUDY DESIGN Ninety-four consecutive patients were examined through use of both computed tomography and magnetic resonance imaging. On axial computed tomography, anterior disk displacement was defined as the presence of an area of soft tissue density that was semilunar in shape and located in front of the mandibular condyle. RESULTS With magnetic resonance imaging taken as the diagnostic gold standard in evaluation of articular disk position, the sensitivity, specificity, and accuracy for computed tomography were 91%, 100%, and 97%, respectively, in the closed mouth position and 96%, 99%, and 98%, respectively, in the open mouth position. CONCLUSIONS The detectability on axial helical computed tomography of anterior displacement of the articular disk in the temporomandibular joint in the open mouth position was almost equal to that on magnetic resonance imaging. It is recommended that the open mouth position be added when helical computed tomography is used to evaluate patients with temporomandibular joint disease.

Meningioma in the tela choroidea of the third ventricle: CT and angiographic correlations

SummaryA meningioma of the tela choroidea of the third ventricle is rare. CT and detailed analysis of angiographic findings in such a case are presented. CT facilitated the detection of rough location of the tumor and the prediction of its histological features. Carotid and vertebral angiographies were utilized in detailing the three-dimensional, gross anatomical relationship between tumor and the surrounding brain structures. Vertebral angiography also contributed to predicting the histology of the tumor.

Atrophy of bilateral extraocular muscles : CT and clinical features of seven patients

Swelling of the extraocular muscles is a common orbital abnormality that is easily demonstrated by computed tomography (CT). However, muscle atrophy is more difficult to identify and is rarely reported in the literature. Bilateral atrophy is extremely rare. We report the CT and clinical features of seven patients showing bilateral extraocular muscle atrophy: four with mitochondrial myopathy (MM) and three with myasthenia gravis (MG). Six patients had clinical histories of muscle involvement > 20 years. An incorrect diagnosis of MG was made initially in two patients with MM because of mildly positive Tensilon testing. The ocular motor abnormalities failed to improve after thymectomy in the myasthenic patients. Orbital appearance on neuroimaging is similar in these disorders. Differentiation between these two disorders is impossible with orbital CT and magnetic resonance imaging (MR) alone.

Solitary plasmacytomas of the occipital bone: a report of two cases

Abstract. The radiological appearances of two cases of solitary plasmacytoma in the occipital bone are described. One arose in the lateral part and the other in the squama. They showed characteristic radiological features on CT, MRI and angiography. Bone scintigraphy and gallium scintigraphy were also available. Solitary plasmacytoma of the skull is a rare condition and usually occurs in the calvarium. The skull base is an extremely rare site and only four cases have been reported. The literature of solitary plasmacytoma of the skull is reviewed.