Neuroradiology 0028-3940

Curati, W. L.; Williams, E. J.; Oatridge, A.; Hajnal, J. V.; Saeed, N.; Bydder, G. M.

doi: 10.1007/s002340050335pmid: 8957793

To assess the potential of registration of images before and after contrast medium for improving the demonstration of contrast enhancement, we compared conventional 2 D T 1-weighted spin-echo images with precisely registered 3 D volume images and subtraction images derived from them in 2 normal subjects and 30 patients with a variety of brain disease. The volume images were registered to subvoxel accuracy using a rigid body translation and rotation, sinc interpolation and a least-squares fit; subtraction images were obtained from these. Normal contrast enhancement was demonstrated better with positionally registered volume and subtraction images than with conventional images in the meninges, ependyma, diploic veins, scalp, skin, orbit and sinuses. Abnormal enhancement was seen better in meningeal disease, multiple sclerosis and tumours as well as on follow-up studies. Subvoxel registration of images before and after contrast medium may be of considerable value in the recognition of contrast enhancement where there are small changes, or where the changes affect tissues with high or low baseline signal values. The technique also appears likely to be of value in demonstrating contrast enhancement in tissues at inferfaces and at other areas of complex anatomy, and in follow-up studies.

Sankhla, S. K.; Gunawardena, W. J.; Coutinho, C. M. A.; Jones, A. P.; Keogh, A. J.

doi: 10.1007/s002340050336pmid: 8957794

We report preliminary experience with the use of magnetic resonance angiography (MRA) in the assessment of intracranial aneurysms. The aims of the study were to confirm that aneurysms could be detected and to assess the quality of the images with a view to early surgery if clinically indicated. We studied 51 patients with recent spontaneous subarachnoid haemorrhage with MRA, using a three-dimensional time-of-flight technique. The results of MRA were subsequently confirmed on intra-arterial digital subtraction angiography (IA-DSA) for anatomical correlation, and were considered satisfactory in 38 patients (74.5 %). In 20 patients early surgical obliteration of their aneurysm was possible on the MRA results without recourse to IA-DSA. A total of 37 aneurysms were identified in 32 patients, while the remaining 6 patients did not have an aneurysm. MRA was misinterpreted in 4 patients (7.9 %), and in 9 other patients (17.6 %) MRA was unsatisfactory due to movement artefacts.

Piotin, M.; Miralbés, S.; Cattin, F.; Marchal, H.; Amor-Sahli, M.; Moulin, T.; Bonneville, J. F.

doi: 10.1007/s002340050337pmid: 8957795

We describe the MRA and MR angiography (MRA) features of persistent trigeminal artery (PTA) found incidentally in eight patients, with special attention to its origin, site and course. The different patterns of posterior communicating arteries were also noted. The PTA were shown on sagittal, coronal and axial MRI and on MRA. In four cases, the PTA arose from the lateral aspect of the intracavernous internal carotid artery, ran caudally, passing round the bottom of the dorsum sellae to join the basilar artery. In the other four cases, it arose from the medial aspect, ran caudally through the sella turcica and pierced the dorsum sellae to join the basilar artery. The posterior communicating arteries were present unilaterally in five cases and bilaterally in one, and absent bilaterally in two. Identification of a PTA with a trans-sellar course is crucial if a trans-sphenoidal surgery is planned.

Baumgartner, R. W.; Mattle, H. P.; Schroth, G.

doi: 10.1007/s002340050338pmid: 8957796

A transcranial colour-coded duplex sonography (TCCD) study was performed to evaluate the sensitivity of detection and the feasibility of visualising details of cerebral arteriovenous malformations (AVMs). We prospectively examined 15 patients with 2 large (> 4 cm), 7 medium-size (2–4 cm) and 6 small (< 2 cm) radiologically proven supratentorial AVMs of the brain using TCCD. A feeding vessel was diagnosed if the velocities and/or the relative interhemisphere velocity difference between feeding and non-feeding anterior, middle and posterior cerebral arteries were more than two standard deviations above the means of 136 age- and sex-matched normals. The sonographer was blinded to the results of cerebral angiography. Using TCCD it was possible to detect all large and medium-size lesions, and 4 of 6 small ones, because 23 of 29 (79 %) feeding arteries showed abnormal haemodynamics. In addition, 8 of 46 (17 %) feeding branches of cerebral arteries were shown. However, all but 2 large draining veins and sinus were not detected. In view of the availability of MRI, MRA and angiography, TCCD is not the method of choice in screening for cerebral AVMs. However, careful assessment of the velocities in the intracranial arteries permits incidental detection of cerebral AVMs and characterisation of the haemodynamics in the feeding arteries.

Farrés, M. T.; Grabenwöger, F.; Magometschnig, H.; Trattnig, S.; Heimberger, K.; Lammer, J.

doi: 10.1007/s002340050339pmid: 8957797

The origin of the vertebral artery may be difficult to show on sonography or conventional angiography. Our aim was to evaluate the accuracy of CT angiography (CTA) in detecting arteriosclerotic changes in the first segment (V1) of the vertebral artery. We performed CTA and intra-arterial digital subtraction angiography (DSA) on 24 patients with vertebrobasilar insufficiency. The ostium and the V1 segment were examined. Stenosis was assessed on a three-grade scale, and calcification and the degree of kinking were recorded. DSA and CTA results were compared. The ostium of the artery was seen in all cases on CTA and in 33 of 47 cases with DSA. All ostial stenoses diagnosed on DSA were seen with CTA. CTA revealed 4 stenoses in cases in which angiography proved inadequate, 11 zones of calcification and 5 cases of luminal reduction due to calcified plaques undetected on DSA. In the V1 segment DSA and CTA showed 3 stenoses, 9 cases of kinking, 1 of coiling and 4 stenoses due to kinking. CTA also demonstrated 4 additional stenoses, 2 cases of kinking and 3 stenoses due to kinking.

Rand, T.; Kink, E.; Sator, M.; Schneider, B.; Huber, J.; Imhof, H.; Trattnig, S.

doi: 10.1007/s002340050340pmid: 8957798

MRI is a sensitive tool for the investigation of pituitary microadenomas but cannot be used as a screening investigation. To establish a strategy for the use of MRI in patients with hyperprolactaemia we investigated 74 women with serum prolactin levels above 52 ng/ml for the presence of microadenomas. We examined 55 premenopausal and 19 postmenopausal women, using a 1.5 T unit. We used T 1-weighted spin-echo sequences, with coronal and sagittal images before and after intravenous gadolinium. We found microadenomas in 38 patients (51.3 %), macroadenomas in 6 (8.1 %) and an infundibular glioma in 1; 29 patients had a normal pituitary gland (39.2 %). The size of the adenomas was related to the prolactin level, and the mean level in patients with MRI evidence of adenomas was higher than in patients without microadenomas (155.72 ± 131.01 ng/ml versus 110.14 ± 80.86 ng/ml). The probability of the presence of an adenoma increased with rising serum prolactin levels. We suggest MRI in patients with prolactin levels more than 100 ng/ml. In patients on oestrogen therapy MRI should be performed with only slightly elevated prolactin levels. Evidence of a microadenoma should be considered in planning further therapy, especially concerning the use of hormone replacement therapy or of bromocriptine.

Rodríguez, O.; Mateos, B.; de la Pedraja, R.; Villoria, R.; Hernando, J. I.; Pastor, A.; Pomposo, I.; Aurrecoechea, J.

doi: 10.1007/s002340050341pmid: 8957799

Our purpose was to correlate the morphological changes seen on MRI studies of the sellar region after trans-sphenoidal resection of pituitary adenomas with clinical and hormonal studies. Between January 1993 and March 1994, 16 patients with a pituitary adenoma (9 macroadenomas and 7 microadenomas) were subjected to trans-sphenoidal resection and included in a prospective study. The protocol consisted of MRI, hormonal and visual studies at the following times: immediately postoperative (1st week), 1st month, 4th month and 1st year after surgery. The evolution of the contents of the sella turcica (tumour remnant, packing material and gland tissue), effects on the infundibulum, optic chiasm, cavernous sinus and sphenoid sinus were correlated with the clinical and hormonal studies. Stabilisation of the postsurgical changes occurred by the 4th month. Tumour remnants were noted in the immediate postoperative period in macroadenomas. Compression of the infundibulum was the only reliable indicator of possible involvement. Optic chiasm compression, defined as close contact between the chiasm and the tumour, was the only morphological finding that indicated visual impairment. There was no standard repneumatisation pattern in the sphenoid sinus, since mucosal changes resembling sinusitis were one of the postsurgical changes. We found MRI not to be useful for follow-up of microadenomas.

Baum, K. A.; Schulte, C.; Girke, W.; Reischies, F. M.; Felix, R.

doi: 10.1007/s002340050342pmid: 8957800

The clinical significance of incidental white-matter foci seen on MRI is controversial. Mainly using a computer-assisted neuropsychological test battery, we tested the hypothesis that there is a clinical correlate of these foci. We studied 41 individuals aged 45–65 years with no history of neurological or psychiatric disorder, in whom no indication of central nervous system abnormalities was found on standardised neurological examination. A computer-assisted neuropsychological test battery, with the advantage of precise measuring of both time and deviation (e. g. in position memory tests), and rating scales for emotional dysfunction were administered; selected soft neurological signs were assessed. In 16 subjects (39 %) MRI showed high-signal foci in the white matter on spin-echo sequences. White-matter foci not adjacent to the lateral ventricles were found to be related to performance on immediate visual memory/visuoperceptual skills, visuomotor tracking/psychomotor speed and, to a lesser degree, learning capacity and abstract and conceptual reasoning skills. Subtle cognitive dysfunction would appear to be a clinical correlate of punctate white-matter foci on MRI of otherwise “healty” individuals.

Gerber, S.; Biondi, A.; Dormont, D.; Wechsler, B.; Marsault, C.

doi: 10.1007/s002340050343pmid: 8957801

To study the long-term evolution of cerebral lesions in neuro-Behçet's disease, MRI was carried out on 12 patients, with follow-up from 1.5 to 6 years (mean 3.5 years). On the first MRI, 66 lesions in all were found; each patient had 1–10 lesions (mean 5.5). There were 30 (46 %) lesions in the brain stem, 18 (27 %) in the basal ganglia region and 18 (27 %) in the periventricular white matter. Of these 22 (33 %) were small, 31 (47 %) medium-size and 13 (20 %) large lesions. On the last MRI, 60 lesions were found; each patient had 1–10 lesions (mean 5). At this time 31 lesions (52 %) were in the brain stem, 13 (22 %) in the basal ganglia region and 16 (26 %) in the periventricular white matter. There were 41 (68 %) small, 13 (22 %) medium-size and 6 (10 %) large lesions. About 40 % of the lesions disappeared, 35 % reduced in size and 25 % remained unchanged. No lesion had enlarged. Of the 60 final lesions 20 (34 %) were not observed on the first study. Small new lesions were found in 5 of 12 patients (42 %), and were asymptomatic. Medium-size or large new lesions were found in 2 patients (17 %) who had stopped steroid treatment and had a neurological relapse. Enlargement of the ventricular system or worsening of initial cerebral atrophy was observed in 9 of 12 patients. Appearance of small lesions and worsening of cerebral atrophy on long-term follow-up suggest the possibility of subclinical progression of cerebral vasculitis and should be considered in the prognosis of neuro-Behçet's disease.

Gass, A.; Barker, G. J.; Riordan-Eva, P.; MacManus, D.; Sanders, M.; Tofts, P. S.; McDonald, W. I.; Moseley, I. F.; Miller, D. H.

doi: 10.1007/s002340050344pmid: 8957802

We investigated the MRI appearance of the optic nerve and its cerebrospinal-fluid-containing sheath in 17 patients with benign intracranial hypertension (BIH) and 15 normal controls. Using phased-array local coils, 3-mm coronal T2-weighted fat-suppressed fast spin-echo images were obtained with an in-plane resolution of < 0.39 mm. The optic nerve and its sheath were clearly differentiated. An enlarged, elongated subarachnoid space around the optic nerve was demonstrated in patients with BIH. High-resolution MRI of the optic nerve offers additional information which may be of value for diagnosis and in planning and monitoring treatment.