Clinical features of sudden hearing loss associated with a high signal in the labyrinth on unenhanced T1-weighted magnetic resonance imaging.

We report on five patients with high signals in the labyrinth on unenhanced magnetic resonance imaging who developed sudden hearing loss and vertigo. Weissman et al. (1992) suggested the possibility that such high signals were caused by hemorrhage. We assessed these patients using audiograms, caloric tests, and auditory brainstem responses to investigate the possibility of inner ear hemorrhage. Most of the patients were found to have severe and irreversible impairment of both cochlear and vestibular function. These findings were consistent with the hypothesis that their symptoms were caused by inner ear hemorrhage.

[Intraarterial chemotherapy for uterine cervical adenocarcinoma: evaluation of its efficacy as neoadjuvant therapy].

We performed preoperative intraarterial chemotherapy in twenty cases of uterine cervical adenocarcinoma (stage Ib: 2, II: 15, III: 3) and evaluated the efficacy of this therapy. The dosages used were 75-120 mg of CDDP, 10-20 mg of MMC and 30-60 mg of EPIR. These drugs were administered by intraarterial one-shot infusion twice every three weeks. In five cases, complete response (CR) of the primary lesion was confirmed by histologic examination. There were no cases of CR inpatients with well differentiated adenocarcinoma. Stage reduction was achieved in all cases except three. In all but one case, more than 50% volume reduction was recognized on MR images. These results were not significantly different from those in cases of uterine cervical squamous cell carcinoma in which we performed this therapy. Therefore, we concluded that intraarterial chemotherapy is highly effective and should be carried out as neoadjuvant therapy for advanced uterine cervical adenocarcinoma.

Lymphocytic adenohypophysitis: skull radiographs and MRI.

We report the skull radiograph, CT and MRI findings in three patients with lymphocytic adenohypophysitis mimicking pituitary adenoma. All cases were associated with pregnancy. CT demonstrated a pituitary mass but did not differentiate lymphocytic adenohypophysitis from pituitary adenoma. The skull radiographs showed either a normal sella turcica or minimal abnormalities; they did not show ballooning or destruction. The MRI appearances were distinctive: relatively low signal on T1-weighted images; preservation of the bright posterior pituitary lobe despite the presence of a relatively large pituitary mass, less common in macroadenomas; marked contrast enhancement compared with pituitary macroadenomas; and dural enhancement adjacent to a pituitary mass.

[Postgadolinium MR angiography of normal intradural veins of the thoracolumbar spine].

To evaluate the normal intradural spinal veins, we used postgadolinium three-dimensional time-of-flight MR angiography (MRA) at 1.5T in 7 subjects. MR images and MR angiograms[32/6/1 (TR/TE/NEX)] were obtained after a bolus injection of Gd-DTPA (0.15-0.2 mmol/kg). We reconstructed images using an equipped function, so-called multiplanar reconstruction. The anterior median veins in 2 patients and the posterior median veins were shown in 2. The great medullary veins were demonstrated in 2. We successed in obtaining venous angiograms by postgadolinium MRA. Disseminated tumors and abnormal enhanced cauda equina are often indistinguishable from normal intradural veins. This study suggests that it is useful to know the MR angiographic features of normal intradural veins in order to evaluate enhanced intradural components.

[CT findings of primary pulmonary cryptococcosis].

Ten cases of primary pulmonary cryptococcosis are presented. The patients' ages ranged from 19 to 71 years and all were males. All patients underwent chest X-ray, tomography and CT (two cases were in additional to HRCT). The most common radiographic findings were single masses (70%) which had to be differentiated from lung cancer or pulmonary tuberculosis. The second pattern of involvement was that of multiple nodules (20%) which may be mistaken for tuberculosis. The third was an infiltrative pneumonitis shadow (10%). By means of CT (HRCT), we revealed that most cryptococcosis lesions exist in the posterior segments (S2, S1, S6 and S1+2) and show cavity formation (30%). Therefore, CT, especially HRCT, may be useful for the differentiation of pulmonary cryptococcosis from neoplasm.

[A case of deep sylvian meningioma presenting temporal lobe epilepsy].

A rare case of deep sylvian meningioma is presented. A 62-year-old woman was admitted to our hospital because of one year history of temporal lobe epilepsy. She had no neurological deficit except for EEG abnormality. CT scans showed a small calcified mass in the left temporal lobe adjacent to the sylvian fissure with no enhancement by contrast medium. The mass was low-intense in both T1- and T2-weighted MR images. The T1-weighted image after the infusion of gadolinium revealed enhancement of the middle cerebral artery adjacent to the mass, similar to dural tail sign. Left external carotid angiography did not show any tumor stain nor the dilatation of the middle meningeal artery. Left internal carotid angiography disclosed enlarged middle cerebral artery without tumor stain. A left frontotemporal craniotomy was performed and the mass was totally removed. The tumor was located deep in sylvian fissure without any connection to the dura or ventricular system, which was firmly adherent to the middle cerebral artery. The histological examination of the surgical specimen revealed a psammomatous meningioma. Meningiomas are believed to originate from the arachnoid cap cells and can arise from various intracranial locations where arachnoid cap cells exist. The majority of them are attached to the dura, choroid plexus, or the tela choroidea. Only eleven cases of deep sylvian meningiomas have been presented in the literature. We have reviewed the clinical and radiological findings in such meningiomas. MR findings in deep sylvian meningioma have not been described.(ABSTRACT TRUNCATED AT 250 WORDS)

Potential usefulness of an artificial neural network for assessing ventricular size.

An artificial neural network approach was applied to assess ventricular size from computed tomograms. Three layer, feed-forward neural networks with a back propagation algorithm were designed to distinguish between three degrees of enlargement of the ventricles on the basis of patient's age and six items of computed tomographic information. Data for training and testing the neural network were created with computed tomograms of the brains selected at random from daily examinations. Four radiologists decided by mutual consent subjectively based on their experience whether the ventricles were within normal limits, slightly enlarged, or enlarged for the patient's age. The data for training was obtained from 38 patients. The data for testing was obtained from 47 other patients. The performance of the neural network trained using the data for training was evaluated by the rate of correct answers to the data for testing. The valid solution ratio to response of the test data obtained from the trained neural networks was more than 90% for all conditions in this study. The solutions were completely valid in the neural networks with two or three units at the hidden layer with 2,200 learning iterations, and with two units at the hidden layer with 11,000 learning iterations. The squared error decreased remarkably in the range from 0 to 500 learning iterations, and was close to constant over two thousand learning iterations. The neural network with a hidden layer having two or three units showed high decision performance. The preliminary results strongly suggest that the neural network approach has potential utility in computer-aided estimation of enlargement of the ventricles.

Ectopic prolactinoma on MRI.

OBJECTIVE: We present two patients with ectopic prolactinoma in the sphenoid sinus who were examined by MRI. MATERIALS AND METHODS: Endocrinological evaluations including spontaneous and drug-induced secretion of prolactin (PRL) and MRI features of two patients with ectopic prolactinoma were studied. RESULTS: Both patients had elevated serum PRL levels, and the endocrinological evaluations were similar to those in ectopic prolactinoma. Magnetic resonance of the head revealed a mass occupying the sphenoid sinus with partially empty sella in Case 1 and with normal pituitary gland in Case 2. Ectopic PRL secretion was confirmed by immunocytochemical examination of the ectopic tumor. Case 1 was treated with bromocriptine, leading to marked decrease in serum PRL levels and reduction of tumor size. Transsphenoidal surgery was performed in Case 2, resulting in normalization of serum PRL levels. CONCLUSION: It is necessary to consider ectopic prolactinoma for the differential diagnosis of the sphenoid sinus tumors.

Enhanced high-resolution sagittal MRI of normal pineal glands.

OBJECTIVE: Our goal was to determine the appearance and enhancement pattern of human pineal glands on MRI. MATERIALS AND METHODS: High-resolution sagittal MR images (3 mm section thickness with an 18 cm field of view) obtained in 60 patients were retrospectively analyzed to determine the size and enhancement patterns of normal pineal glands following the intravenous injection of contrast medium. RESULTS: Pineal glands were either solid (40%) or cystic (60%) with various enhancement patterns: diffuse (15%) and partially enhanced (25%) in solid and ring-like (20%) and peripherally partial (40%) in cystic. Their diameter exceeded 10 mm but was < 20 mm in five cases and resembled cystic pineal neoplasms. Two such cases were found to be histologically normal. CONCLUSION: Information on the appearance and enhancement patterns of normal pineal glands on MR images can improve the accuracy of diagnosing space-occupying lesions in the pineal region and perhaps help to prevent unnecessary surgery.

[Gd-DTPA-enhanced MR imaging of the normal facial nerve].

We performed a prospective imaging study of the normal facial nerve within the temporal bone before and after injection of Gd-DTPA. The study included 29 patients using a 1.5T superconducting unit and 40 nerves (right: 21; left: 19) were available for analysis. There was no enhancement of the facial nerve within the internal auditory canal in the entire series. However, the enhancement at the labyrinthine segment was observed in one nerve (3%); at the geniculate ganglion in seven (18%); at the tympanic segment in 18 (45%) and at the mastoid segment in 28 nerves (70%). Our results indicate that enhancement of the facial nerve in normal subjects is not a rare condition.

[MR imaging of the thymoma--differentiation of invasive thymoma from noninvasive thymoma].

Magnetic resonance imaging (MRI) findings were reviewed in nine patients with histologically confirmed thymoma. The morphologic findings obtained by MRI were useful in distinguishing invasive from noninvasive thymoma. Invasive thymomas (2 cases) showed irregular contours and broad obliteration of the fatty plane between the mass and great vessels on T1-weighted coronary images. Perivascular infiltration shadow was considered to be characteristic of invasive thymoma. Noninvasive thymomas (7 cases) were round or oval in shape and showed slight obliteration of the fatty plane. In conclusion, MRI was helpful in differentiating invasive from noninvasive thymoma and defining the extent of thymoma.

[Sagittal MR images of normal pineal glands after Gd-DTPA injection].

We evaluated normal pineal glands on Gd-DTPA enhanced MR images on a 1.5 Tesla superconducting unit. On enhanced sagittal MR images with a 3-mm slice thickness, pineal glands were identified as solid or cystic structures. The solid and cystic pineal glands were divided into two subgroups according to the degree of enhancement. The solid pineal glands showed diffuse or subtle enhancement and cystic ones showed peripheral enhancement either completely or incompletely. Of the 50 patients, 19 (38%) had solid pineal glands and 31 (62%) had cystic ones. In male, 7 out of 11 (63%) showed solid pineal glands and in female, 27 out of 39 (70%) showed cystic ones.

Multiple sclerosis simulating brain tumor on computed tomography.

A 44-year-old woman with multiple sclerosis (MS) stimulating a brain tumor on CT is reported. At the first hospitalization, a heterogeneously enhancing mass lesion with perifocal edema was identified on CT in the left parietal lobe. Biopsy of the lesion revealed necrotic change of the brain, gliosis, and perivascular cuffing; several months later no tumor cells were identified. The follow-up CT revealed reduction of the enhancing lesion and disappearance of the perifocal edema, with only a low density area persisting. At the second hospitalization, CT revealed a ring enhancing lesion with perifocal edema in the right temporoparietal region. Follow-up CT several months later revealed reduction of the lesion, with the residual of a small low density area. Magnetic resonance (MR) allowed us to identify multiple lesions in addition to those visualized on CT. In some cases of MS, the CT findings are very similar to those found in brain tumors. In these instances, MR is more useful in the diagnosis of MS than CT.

Monostotic fibrous dysplasia of the left parietal bone--case report.

A 14-year-old female presented with a hard, painless mass, 5 x 5 cm, in the left parietal region. Skull x-rays showed a radiolucent skull tumor with a sclerotic margin in the parietal region. Computed tomography revealed an intradiploic multilocular mass separated by bony trabeculae. The outer table had thinned and protruded outward. The inner table was also thin and protruded inward slightly. External carotid angiography revealed a faint tumor stain and feeding from the middle meningeal artery. Bone scintigraphy revealed abnormal uptake in the lesion. Total removal of the skull tumor and cranioplasty were performed. The histological diagnosis was fibrous dysplasia. Fibrous dysplasia within the cranial vault is often expressed as painless bulging without neurological symptoms. Surgery is recommended when neurological symptoms and/or cosmetic problems are present. Histological confirmation of the diagnosis is also important.

Congenital muscular dystrophy (Fukuyama type)--changes in the white matter low density on CT.

Sixty-two computed tomographic (CT) scans of 36 patients with congenital muscular dystrophy of Fukuyama type (FCMD) were analysed. A low density area in the cerebral white matter was characteristic of FCMD and a special reference was made to the changes in the white matter low density. It was present in 15 patients out of 36 (42%) and frequently seen in the scans obtained on the younger patients; among 11 scans taken of patients between 1 and 2 years of age, 10 scans (91%) showed the white matter low density. Repeated CT scans were carried out on 26 of the 36 cases. Follow-up study revealed that the white matter low density areas were most apparent around the age of one year and decreased or disappeared at 2 or 3 years of age. From these observations, delayed myelination was suspected for the pathogenesis of the low density area found in FCMD.

Facial nerve neuromas: CT findings.

Although neuromas of the facial nerve are rare, they present with uniform clinical and radiological findings. Their pluridirectional tomography findings have been well described; however, the appearance of the intracranial extension of the neuroma which is best visualized by CT has not been emphasized. We report five cases of facial nerve neuromas with particular attention to their intracranial extension. For comparative purposes we also have reviewed 10 cases of acoustic and eight cases of trigeminal neuromas, all involving the cerebellopontine angle (CPA) and the middle cranial fossa. Two of the five facial nerve neuromas affected the second and third segments of the facial canal, and three involved both the CPA and the middle cranial fossa spreading across the midpetrosal bone. This type of tumor extension seems to be characteristic of facial nerve neuromas. In acoustic and trigeminal neuromas the tumor crossing toward the middle fossa takes place via the tentorial hiatus (acoustic) and the petrous apex (trigeminal).