Radiologic anatomy of the spinal dorsal horn at the cervical level (anatomic-MRI correlations).

The spinal dorsal horn is known for its important functional role in the field of transmission and modulation of sensory afferents. Because of this, the dorsal horn represents a target for numerous analgesic and antispastic procedures. Thus, it would be interesting to develop imaging dedicated to this spinal structure. The purpose of this study was to investigate the radiologic anatomy of the cervical dorsal horn by magnetic resonance imaging (MRI) (1.5T). The first step consisted in the validation of the anatomic information provided by MRI on 5 human cadavers. A spin-echo sequence (T2, 2000/45) enabled the demonstration of good correlations between histologic sections and axial MRI slices performed at the corresponding cervical levels. The second step was the <> exploration of 20 subjects, aiming at the development of a gradient echo sequence (T2*) with a conventional MRI unit, compatible with a routine clinical examination. The dorsal horn was clearly identified in 77% of the axial slices performed (n = 300). The angle between the dorsal horn axis and the sagittal plane was measured as from 25.5 degrees at C2 to 40 degrees at C8 segments. The results of this anatomico-radiologic study of the cervical dorsal horn suggest that preoperative MRI could be useful to design the surgical approach to this structure, as performed during cervical microsurgical drezotomy (DREZ = dorsal root entry zone) for the treatment of selected cases of chronic pain or disabling spasticity in the upper limbs.

[Diagnosis of a post-thrombophlebitic dural fistula using MR angiography]. / Diagnostic d'une fistule durale post-thrombophlébite par angio-MR.

We report a case in which MRA made it possible to diagnose a dural arteriovenous fistula and thrombophlebitis in a 23-year old woman. 2D TOF MRA is the usual technique in the diagnosis of thrombophlebitis. Our experience shows the limits of 2D TOF since the increased signal intensity in the sinus could simulate a normal flow, and we describe the advantages of MR subtraction angiography. In our study, 3D TOF MRA showed the dural arteriovenous fistula, its location near the right transverse sinus and some of the feeding vessels: tentorial branch of the internal carotid artery and meningeal branch of the right occipital artery. 3D TOF MRA provides the diagnosis of dural arteriovenous fistula, but it cannot replace the plain angiography performed before endovascular or surgical treatment.

Clinical and radiological aspects of Villaret's syndrome.

A 68-year-old man with a history of large cell lung carcinoma presented 1 year after surgical management of the initial lesion, with a complete unilateral IX-XII cranial nerve palsy with Horner's sign. This rare multiple cranial nerve palsy is called Villaret's syndrome. It suggests an extracranial lesion located in the retroparotid space. Complete basal skull radiology work up including computed tomography and magnetic resonance imaging confirmed the location of the causal lesion in the retroparotid space.

Inhaled oxygen: a brain MR contrast agent?

Oxygen inhalation led to subtle but readily detectable changes on T2*-weighted images with a conventional MR imager at 1.5 T. We attribute the increase in local signal intensity to changes in blood oxygenation, in particular to a net conversion of deoxyhemoglobin to oxyhemoglobin.

CT-guided needle biopsy of intracranial tumours: results in 118 consecutive patients.

The purpose of this paper is to evaluate the efficacy and safety of CT-guided needle biopsies and to determine the optimal indications for this technique. The case histories of 118 patients who underwent a CT-guided biopsy for brain lesions during a six-year period, from November 1986 to September 1992, were reviewed. During a preliminary CT-scan, the entry site was determined and localized using a radio opaque marker and the safest route to the lesion was chosen. One hundred and thirty four procedures were performed in 118 patients. A positive diagnosis of tumour was obtained in 106 patients (89.8%). Repeat procedures were required in 18 patients. High-grade gliomas were the more common lesions (55.1%). Morbidity and mortality was assessed over the 30-day period after the procedure. Nine patients died during this time. Eight patients from day 3 to day 30 in the expected course of their disease and one within 48 first hours from neurological deterioration following the procedure. We found that CT-scan guided biopsies are a safe and accurate way to obtain brain tissue specimens for pathological diagnosis in selected cases. For superficial and large tumours it is a simple, fast and effective procedure.

Striatocapsular infarction: MRI and MR angiography.

We present a case of left striatocapsular infarction manifest clinically as a transient right hemiparesis. MRI showed a left striatocapsular infarct. Striatocapsular infarction, unlike lacunar infarction, is often associated with occlusive disease of the carotid artery. In order to screen the carotid vessels, cervical MR angiography (MRA) was performed during the same examination, demonstrating a left internal carotid artery occlusion, confirmed by contrast arteriography. MRA, a noninvasive modality, can be a useful adjunct to MRI, when diagnostic information concerning the cervical carotid artery is needed.

Intracranial aneurysm associated with pituitary adenoma shown by MR angiography: case report.

We present a case of aneurysm of the anterior communicating artery associated with a pituitary adenoma. Recognition of this association has important clinical implications, leading to modification of the surgical approach. The aneurysm was shown on MR angiography and confirmed with contrast arteriography and at surgery.

Spontaneous calcific cerebral emboli from calcified aortic valve stenosis.

Calcific cerebral emboli (CE) are a rare complication of calcified aortic valve stenosis (CAS). These emboli usually result from diagnostic manoeuvres (e.g. left heart catheterization) or from therapeutic procedures (e.g. heart valve surgery). Spontaneous calcific emboli are exceptional. We present the cases of two subjects known to have CAS who presented with acute neurological disorders suggesting strokes. In both subjects CT scans of the skull and brain provided a diagnosis of spontaneous CE by showing calcium-dense dots located on vessels or within the cerebral parenchyma. Additional examinations enabled us to determine the origin (heart or carotid artery) of these emboli. The finding of spontaneous cerebral CE is a very strong argument in favour of surgical valve replacement in these patients.

Dural fistulae of the cavernous sinus treated by embolization. Ten cases.

We report ten cases of dural fistulae of the cavernous sinus treated by the endovascular route. The fistulae were fed by the internal and external carotid arteries. All patients presented with ophthalmic symptoms and/or headache and/or intracranial murmur. Embolization was decided on the ground of all in visual acuity, exophthalmos, ophthalmoplegia or sudden exacerbation of clinical symptoms. It was performed after selective catheterization of external carotid feeders with non-resorbable particles. The shunt was totally occluded in 7 cases, and local signs were improved in all patients: the intracranial murmur disappeared in 2 out of 4 cases and headache was relieved in 2 out of 3 cases. No permanent complication was observed. Among the various possible treatments of these dural fistulae, embolization of branches of the external carotid artery is a simple, effective and safe method, provided its principles and indications are respected.

MRI in Sturge-Weber syndrome.

Five children (3 girls, 2 boys, aged from 1 to 18 years) presenting with Sturge-Weber syndrome were explored by MRI with contrast injection in 2 cases. The respective positions of CT and MRI are discussed: CT is the method of choice to display leptomeningeal calcifications. MRI seems to be more accurate than CT to determine the location of the lesions and to demonstrate the enhancement of the angioma after contrast injection.

Demonstration of subclavian steal by MR angiography.

We present three cases of subclavian steal syndrome demonstrated by MR angiography. By using a presaturation pulse located at the bottom or at the top of the acquisition volume we demonstrated the flow direction of vertebral arteries. We used a new investigational two-dimensional time-of-flight sequence.