Biomedical subjects

Xavier Leclerc

Publications and source records attributed to Xavier Leclerc.

23 records · Page 2Linked to original sources

PubMed2002

The potential of proton magnetic resonance spectroscopy ((1)H-MRS) in the diagnosis and management of patients with brain tumors.

Proton ((1)H) magnetic resonance spectroscopy (MRS) is a noninvasive method that can monitor the metabolic changes in most brain diseases. This technique is now available on current 1.5 Tesla magnetic resonance units and does not require sophisticated software or time-consuming post-processing techniques. Previous studies using single-voxel techniques showed the usefulness of MRS for the diagnosis of brain tumor despite some technical issues, including spatial resolution and volume coverage. Recent advances have been made through the use of multivoxel techniques and metabolite maps, which allow assessment of both the entire volume of the lesion and the surrounding normal-appearing brain tissue. Recent studies suggest the potential of this technique to guide biopsies, to define radiotherapy targets, and to monitor patients after treatment. Some persistent drawbacks, including measurement time and spectral resolution, will probably be overcome in the near future.

Adult↗

PubMed2002

Aneurysms of the anterior communicating artery treated with Guglielmi detachable coils: follow-up with contrast-enhanced MR angiography.

BACKGROUND AND PURPOSE: The long-term outcome of patients treated with Guglielmi detachable coils (GDCs) remains unknown and is being evaluated. We sought to assess the feasibility and utility of contrast-enhanced MR angiography in the follow-up of anterior communicating artery (AcomA) aneurysms treated with GDCs. METHODS: In a prospective study, 20 consecutive patients with AcomA aneurysms underwent digital subtraction angiography (DSA), time-of-flight MR angiography (TOF-MRA), and contrast-enhanced MR angiography (MRA) 12 months after treatment with GDCs. The aneurysmal sac measured less than 10 mm in 19 patients and 12 mm in one patient. Two observers who did not analyze the DSA images independently reviewed the MRA images. Aneurysms were classified according to the presence of a residual neck (ie, complete occlusion, small residual neck, large residual neck, or not assessable). DSA was used as the standard of reference. RESULTS: Images from all examinations were assessable. Venous enhancement was observed in five cases at contrast-enhanced MRA; this did not affect image interpretation. Interobserver agreement was good. A comparison of the techniques showed good agreement in the detection of a residual neck. Two cases of a small residual neck were not detected at TOF-MRA, and one case of complete occlusion was misclassified as a small residual neck at contrast-enhanced MRA. CONCLUSION: Our findings showed that contrast-enhanced MRA is a valuable method for the follow-up of aneurysms in the AcomA after their treatment with GDCs. Further studies with multiple aneurysm locations and larger groups are required to determine the exact role of this technique.

Adolescent↗

PubMedDate not supplied

Endovascular treatment of peripheral cerebellar artery aneurysms.

BACKGROUND AND PURPOSE: Peripheral cerebellar artery aneurysms are rare and difficult to treat surgically. We report the angiographic results and the clinical outcomes for eight patients treated by embolization for peripheral cerebellar artery aneurysms. METHODS: Between 1994 and 2001, eight patients with peripheral cerebellar artery aneurysms were referred from the neurosurgery department for endovascular treatment. The patients consisted of four women and four men with a mean age of 43 years (range, 16-68 years). Seven patients presented with subarachnoid hemorrhage. In one patient, the aneurysm was incidental. In five cases, selective embolization of the aneurysmal sac was performed using GDCs. Two large peripheral cerebellar artery aneurysms and one small aneurysm with a wide neck were treated by parent vessel occlusion. Mean clinical and imaging follow-up duration was 18.5 months (range, 12-36 months). RESULTS: Endovascular treatment resulted in five complete occlusions, two neck remnants, and one residual aneurysmal flow. Clinical evaluation showed that good or excellent recovery was achieved by all patients. Imaging follow-up revealed seven complete occlusions and one residual aneurysmal flow. CONCLUSION: Our study showed that the endovascular approach to treat peripheral cerebellar artery aneurysms by selective embolization or parent vessel occlusion was feasible, safe, and effective. Imaging follow-up showed excellent anatomic results in accordance with clinical recovery.

Adolescent↗

PubMedDate not supplied

Three-dimensional packing with complex orbit coils for the endovascular treatment of intracranial aneurysms.

BACKGROUND AND PURPOSE: Endovascular treatment of intracranial aneurysms is too often associated with aneurysm recurrence due to coil compaction. High packing of coils prevents compaction. To increase the packing attenuation, we sought to evaluate the results of selective embolization of aneurysms with complex-shaped coils alone. METHODS: Twenty consecutive patients with an intracranial aneurysm were treated by selective embolization. There were 12 women and eight men, with a mean age of 48 years. Fourteen patients presented with subarachnoid hemorrhage, whereas six were asymptomatic. Mean size of aneurysms was 5 mm (range, 3-11 mm). In all cases, we tried to pack the aneurysm with complex coils only (Orbit, Cordis, Miami Lakes, FL), delivered in a concentric fashion. Remodeling technique was used in two cases of wide-neck aneurysms. Clinical and anatomic outcome were assessed by using the modified Glasgow outcome scale and 6-month MR angiography (MRA). RESULTS: From two to five complex coils were delivered within the aneurysms. Occlusion by using complex coils alone was successful in 16 patients, and resulted in 14 complete occlusions and two neck remnants. In four patients, additional helical Orbit coils or Guglielmi detachable coils were required to complete aneurysm obliteration. No technical complication occurred, and clinical outcome was excellent in 14 cases and good in two. Follow-up MRAs were obtained in all patients and showed only one slight recanalization. CONCLUSIONS: Intracranial aneurysms may be treated by selective embolization with complex coils only. Imaging follow-up at 6 months shows a low rate of coil compaction.

Adult↗

PubMedDate not supplied

Three-dimensional dynamic MR digital subtraction angiography using sensitivity encoding for the evaluation of intracranial arteriovenous malformations: a preliminary study.

BACKGROUND AND PURPOSE: Our aim was to develop 3D dynamic MR digital subtraction angiography with high temporal resolution without sacrificing spatial resolution by using sensitivity encoding for the evaluation of cerebral arteriovenous malformations. METHODS: Nineteen patients with 19 angiographically proven arteriovenous malformations (16 supratentorial and 3 infratentorial) were assessed by conventional catheter angiography and 3D dynamic MR digital subtraction angiography. A 3D contrast-enhanced gradient-echo sequence with sensitivity encoding based on a parallel imaging technique was performed and acquired 20 dynamic images, repeated 18 times every 1.7 seconds. Three-dimensional dynamic MR digital subtraction angiograms were analyzed independently by two radiologists in a blinded fashion with regard to arteriovenous malformation nidus and venous drainage. Conventional catheter angiography was used as reference. RESULTS: All MR imaging examinations were assessable. Interobserver agreement was excellent for the detection of nidus and for the evaluation of nidus size (kappa = 1 and 0.875, respectively) but moderate for the visualization of the venous drainage (kappa = 0.56). All nidi detected on conventional catheter angiography were clearly depicted on 3D dynamic MR digital subtraction angiography. The evaluation of the size of the nidus by both techniques was similar. On 3D dynamic MR angiograms, veins were correctly analyzed in 17 of 19 arteriovenous malformations. CONCLUSION: Our preliminary study demonstrates that 3D dynamic MR digital subtraction angiography using sensitivity encoding with a high spatial resolution is appropriate for the assessment of arteriovenous malformations.

Adult↗