Kazutoshi Mukada

MRI of intracranial germ cell tumors

We reviewed MRI findings in proven intracranial germ cell tumours in 22 cases, 12 of whom received Gd-DTPA. On T1-weighted images, the signal intensity of the tumour parenchyma was moderately low in 19 cases and isointense in 3; on T2-weighted images, it was high in all cases. Regions of different intensity thought to be cysts were found in 17 (77%): 7 of 12 patients with germinoma (58%) and in all other cases. Of the 13 patients with pineal lesions T1-weighted sagittal images showed the aqueduct to be obstructed in 5, stenotic in 7 and normal in 1. Strong contrast enhancement was observed in all 12 cases. Of the 14 patients with suprasellar lesions, 5 were found to have an intrasellar extension, and in 3 of these, the normal pituitary gland, which could be distinguished from the tumour, was displaced anteriorly. Ten patients (45%) had multiple lesions.

Intracranial germ-cell tumor with synchronous lesions in the pineal and suprasellar regions: Report of six cases and review of the literature

The features of intracranial germ-cell tumor with synchronous lesions in the pineal and suprasellar regions (GCTSPS) in six patients were investigated. GCTSPS accounted for 12.8% of all germ-cell tumors (GCT) in our brain tumor study group. In all cases, the initial symptoms were attributable to the suprasellar lesion, and symptoms due to the pineal GCT developed only after admission. Five of the six cases were histologically diagnosed as germinoma. In all cases, tumors of both regions disappeared after irradiation, resulting in no recurrence for an average of 55.3 months. Our experience and reports in the literature suggest that GCTSPS is highly sensitive to radiation in most cases, although some reports indicated that recurrence is frequent after radiation therapy alone. It is suggested that histological diagnosis in one of the GCTSPS lesions is undertaken to make a plan for the following treatment.

CT scan of pituitary adenomas

SummaryCT scan is an extremely useful, almost harmless means of diagnosing pituitary adenomas. Growth hormone (GH)-secreting adenomas tend to have higher absorption coefficient on plain CT than the nonfunctioning and prolactin (PRL)-secreting adenomas. The absorption coefficient on contrastenhanced CT does not identify the specific type of adenoma. Ring-like enhancement was observed in five nonfunctioning and four PRL-secreting adenomas with suprasellar extension, while cystic components were observed in four nonfunctioning and four PRL-secreting adenomas. In three of ten cases of PRL-secreting microadenomas, the site corresponding to the adenoma was not enhanced, whereas the normal pituitary was. A correlation exists between the size of PRL-secreting adenoma and the serum PRL level, but not between the size of GH-secreting adenomas and the serum GH level.

Displacement of the normal pituitary gland by sellar and juxtasellar tumours : surgical-MRI correlation and use in differential diagnosis

We compared the position of the normal pituitary gland as estimated by gadolinium (Gd)-DTPA-enhanced MRI, with its position at surgery in 40 patients with intra- and juxtasellar tumours: 22 pituitary adenomas, 4 craniopharyngiomas, 7 meningiomas, 2 germinomas, and 5 Rathke cleft cysts. In 37 of these, the normal gland showed more intense contrast enhancement than the adjacent tumour, from which it could be differentiated by Gd-DTPA-enhanced MRI, especially in the sagittal plane. The direction of displacement of the normal pituitary gland correlated well with tumour type, so that its position proved helpful in the differential diagnosis. The normal gland was typically displaced superiorly by pituitary adenomas, inferiorly by craniopharyngiomas, and anteriorly by germinomas. It showed variable displacement by Rathke cleft cysts, and was not usually displaced by meningiomas.

Application of 4D-CTA using 320-row area detector computed tomography on spinal arteriovenous fistulae: initial experience

Time-resolved computed tomography angiography (4D-CTA) using a 320-row area detector CT scanner has recently been applied in the evaluation of cranial vascular disorders. However, application of 4D-CTA to spinal vascular disorder evaluation has never before been described. The authors herein report their initial experience of 4D-CTA in the evaluation of spinal arteriovenous fistulas (AVFs) and compare this novel modality with other imaging modalities. Four consecutive patients with spinal AVF underwent time-resolved contrast-enhanced magnetic resonance angiography (trMRA), 4D-CTA, and selective catheter angiography (CA). In 4D-CTA, volume data was transformed into 3D volume-rendered images and maximum intensity projection. These images were also evaluated by time-resolved serial phases. Then, images of each modality were compared, focusing on the detection of perimedullary draining veins and the prediction of AVF location and drainage flow direction. All modalities successfully detected perimedullary draining veins in all cases. Location of the AVF was detected in all cases by CA. trMRA and 4D-CTA detected the AVF in three out of the four cases. With regard to flow direction, while 4D-CTA successfully depicted ascending or descending drainage flow in the spinal canal, CA failed to detect the flow direction in one case while trMRA failed in two cases. In the case with epidural AVF, 4D-CTA was the only technique to detect the flow direction of perimedullary drainage. Although this is only an initial experience of the application of 4D-CTA to spinal vascular diseases, 4D-CTA was capable of detecting the dynamic vascular flow of spinal AVFs. The authors believe that 4D-CTA can be a useful option in the evaluation of spinal AVFs.

MRI of pituitary adenomas: the position of the normal pituitary gland

The position of the normal pituitary gland, assessed using gadolinium-enhanced MRI was compared with the position found at surgery for pituitary adenoma in 25 patients. The tumours were five microadenomas and 20 macroadenomas. Using T1-weighted imaging, the anterior lobe could be differentiated on the sagittal image in five patients (20%) and on the coronal image in four (16%). The high intensity of the posterior lobe could be differentiated using T1-weighted sagittal imaging in 13 patients (52%). The normal pituitary gland, which enhanced more strongly than tumour, could be differentiated using Gd-DTPA-enhanced MRI on the sagittal images in 22 cases (88%) and on the coronal image in 17 (68%). In seven patients, the normal pituitary gland surrounded the tumour; it was displaced superiorly in 14 cases and superioposterorly in two but in no case was it displaced anteriorly or downwards.

Cytocidal effects of bromocriptine, somatostatin analog, and heat on growth hormone‐secreting pituitary adenoma in vitro

The effects of bromocriptine (BC), a somatostatin analog (SMS), and heat on the secretion of growth hormone (GH) and prolactin (PRL), and on the morphologic features of human GH‐secreting pituitary adenoma were studied in vitro. The treatment with BC, SMS, or heat (41.5°C and 42.5°c) markedly suppressed the secretion of GH and PRL from the adenoma cells and reduced the number of cells immunoreactive with GH or PRL. The combined treatment with BC and heat induced a marked reduction in the number of GH and PRL cells consistent with the effect on the secretion of GH and PRL. These results suggest that BC, SMS, and heat treatments produced the cytotoxic effects on pituitary adenoma cells, and that the simultaneous treatment of BC and heat enhanced this effect. Cancer 1992; 69:2688‐2696.

Endovascular stenting of symptomatic innominate artery stenosis under distal balloon protection of the internal carotid and vertebral artery for cerebral protection: a technical case report

The use of cerebral protection devices in endovascular treatment for innominate artery (IA) stenosis is not well established. We describe a novel technique for cerebral protection during endovascular stenting of symptomatic IA stenosis. An 82-year-old man presented with acutely scattered brain infarction by artery-to-artery embolism due to IA stenosis. Endovascular treatment for symptomatic IA stenosis was planned to prevent recurrent attacks. Endovascular stenting for IA stenosis via the right femoral artery approach was performed under simultaneous distal balloon protection of the right internal carotid artery (ICA) and vertebral artery (VA) via the right brachial artery approach. Successful treatment of symptomatic IA stenosis was achieved with no complications. The technique with simultaneous distal balloon protection of the ICA and VA provided excellent cerebral protection in stenting of IA stenosis.

Transient headache related to enlargement of the contralateral vertebral artery after vertebral artery occlusion.

BACKGROUND Endovascular proximal parent artery occlusion has been performed for VA dissection. We describe a case that presented with headache associated with transient enlargement of contralateral VA after VA occlusion. CASE DESCRIPTION A 54-year-old man presented with constant occipital headache on the left due to left VA dissection. Proximal parent artery occlusion of the left VA with detachable coils was performed, and the headache disappeared after coil occlusion. However, the patient presented with occipital headache on the right 1 week later. The MRI showed enlargement of the right VA compared with before the procedure. Four weeks later, the right occipital headache disappeared, and MRI showed improvement of enlargement of the right VA. CONCLUSION The patient might present with right occipital headache related to transient enlargement of contralateral VA after VA occlusion. Careful postoperative neuroradiological examination of the contralateral VA is required because contralateral VA enlargement may be caused by hemodynamic stress after VA occlusion.

Relationship between left atrial spontaneous echo contrast and the features of middle cerebral artery territory in nonvalvular atrial fibrillation.

SummaryWe investigated the relationship between left atrial spontaneous echo contrast (SEC) and cerebrovascular features in nonvalvular atrial fibrillation (NVAF). Few reports have been published to compare cardiac and cerebrovascular imaging in patients with NVAF. Forty-four patients with NVAF were studied using transesophageal echocardiography and noninvasive imaging including magnetic resonance imaging (MRI), magnetic resonance angiography (MRA), and transcranial color Doppler imaging (TCD) in the middle cerebral artery (MCA) territory. The symptomatic severity was divided into asymptomatic, transient ischemic attack (TIA), and stroke. The severity of the MRI findings was divided into normal, small, and large infarcts. The severity of the MRA findings was divided into normal, attenuation, and occlusion. MCA was bilaterally scanned and a side-to-side asymmetry ratio of pulsatility index (PI) was measured. The severity of SEC was divided into normal, SEC, and thrombi. Five patients with other thromboembolic risk or poor results of TCD were excluded. SEC and thrombi were detected in 12 (30%) and in 3 patients (5%), respectively. TIA and stroke were detected in 8 (21%) and in 17 patients (44%), respectively. Small and large infarcts were detected in 9 (23%) and in 18 patients (46%), respectively, on MRI. Attenuation and occlusion were detected in 14 (36%) and in 8 patients (21%), respectively, on MRA. PI ratio was 1.21 ± 0.25. SEC severity was highly associated with PI ratio and MRA severity in monovariate analysis (P < 0.005),P < 0.01, respectively). SEC severity was highly associated with PI ratio and MRA severity in stepwise multiple regression analysis (P = 0.0001,r = 0.630,n = 39). In patients with NVAF, left atrial SEC was highly related to attenuation or occlusion on MRA and imbalance of cerebral blood flow on TCD in the MCA territory.