Intraoperative Diffusion-Weighted Imaging for Visualization of the Pyramidal Tracts. Part II: Clinical Study of Usefulness and Efficacy

Abstract

Precise identification and preservation of the pyramidal tract during surgery for parenchymal brain tumors is of crucial importance for the avoidance of postoperative deterioration of the motor function. The technique of intraoperative diffusion-weighted imaging (iDWI) using an intraoperative MR scanner of low magnetic field strength (0.3 Tesla) has been developed. Its clinical usefulness and efficacy were evaluated in 10 surgically treated patients with gliomas (5 men and 5 women, mean age: 41.2+/-13.9 years). iDWI permitted visualization of the pyramidal tract on the non-affected side in all 10 cases, and on the affected side in 8 cases. Motion artifacts were observed in four patients, but were not an obstacle to identification of the pyramidal tract. Good correspondence of the anatomical landmarks localization on iDWI and T (1)-weighted imaging was found. All participating neurosurgeons agreed that, in the majority of cases, iDWI was very useful for localization of the pyramidal tract and for clarification of its spatial relationships with the tumor. In conclusion, image quality and accuracy of the iDWI obtained with an MR scanner of low magnetic field strength (0.3 Tesla) are sufficient for possible incorporation into an intraoperative neuronavigation system. The use of iDWI in addition to structural iMRl and subcortical functional mapping with electrical stimulation can potentially result in a reduction of the postoperative morbidity after aggressive surgical removal of lesions located in the vicinity to the motor white matter tracts.

Advanced Surgical Management of Gliomas: Technological Requirements, Concept of Information-Guided Resection, and Clinical Results

“…Nevertheless, all surgical devices that are used within the 5-gauss line, such as operating table (MOT2000-MRI; Mizuho Ltd., Tokyo, Japan) and operating microscope (MRI-30; Mitaka Co., Tokyo, Japan) are constructed from non-ferromagnetic material to prevent accidents and avoid image artifacts. Originally developed radiofrequency receiver coil integrated with Sugita head-holder (Head-holder coil; Mizuho Ltd., Tokyo, Japan) significantly improved the quality of the intraoperative images (Ozawa et al, 2008a(Ozawa et al, , 2008b. Positioning of the coil in close vicinity to the visualized region provides one an opportunity to perform MRI investigations with minimal distortion artifacts and maximum structure contrasting in any plane irrespectively to orientation of the object.…”

“…It should be marked, however, that diffusion anisotropy of the white matter tracts may be reduced by presence of the tumor or peritumoral edema, which may occasionally lead to poor visualization of the pyramidal tract on the affected side (Ozawa et al, 2008b). …”

Surgical Treatment for Glioma: Extent of Resection Applying Functional Neurosurgery

“…The application of intraoperative MR imaging system involves several challenging issues such as specific operating environment requirements and prolonged scan time, but enables intraoperative confirmation of the position of the tumor to be removed, and enables extraction of real-time tractography data of displaced brain tissues. 35,40) No significant improvement was noted in the overall survival after photodynamic diagnosis-guided malignant glioma surgery utilizing the 5-amiolevulinic acid (5-ALA) marker. However, the 6-month progression-free survival was 41.1% for patients allocated to the 5-ALA group, higher than that (21.2%) for patients allocated to the white light group.…”

Shift of the Pyramidal Tract During Resection of the Intraaxial Brain Tumors Estimated by Intraoperative Diffusion-Weighted Imaging

“…6) An original radiofrequency receiver coil integrated with a modified Sugita head holder (Head-holder coil; Mizuho Ltd., Tokyo) was used. 17,18) During routine procedure iMR imaging was usually performed at least twice: after craniotomy and completeness of the approach to the tumor and after resection of the neoplasm. If additional removal of the lesion is required iMR imaging investigation was repeated.…”