Three-dimensional anisotropy contrast imaging of gliomatosis cerebri: two case reports

Comparison of two fat-suppressed magnetic resonance imaging pulse sequences to standard t2-weighted images for brain parenchymal contrast and lesion detection in dogs with inflammatory intracranial disease

T2-weighted (T2w) sequences are commonly relied upon in magnetic resonance imaging protocols for the detection of brain lesions in dogs. Previously, the effect of fluid suppression via fluid-attenuated inversion recovery (FLAIR) has been compared to T2-weighting with mixed results. Short tau inversion recovery (STIR) has been reported to increase the detection of some CNS lesions in people. The purpose of the current study was to evaluate the effect of fat suppression on brain parenchymal contrast resolution and lesion detection in dogs. We compared three sequences: T2w images, STIR, and T2w FLAIR with chemical fat suppression (T2-FLAIR-FS) in dogs with meningoencephalitis. Dogs with meningoencephalitis and dogs with idiopathic epilepsy were retrospectively identified and anonymized. Evaluators recorded the presence or absence of lesions within 12 predetermined brain regions on randomized sequences, viewing and scoring each sequence individually. Additionally, signal-to-noise ratios, contrast-to-noise ratios, and relative contrast (RC) were measured in a reference population. Short tau inversion recovery sequences had the highest RC between gray and white matter. While descriptively more lesions were identified by evaluators on T2-FLAIR-FS images, there was no statistical difference in the relative sensitivity of lesion detection between the sequences. Nor was there a statistical difference in false lesion detection within our reference population. Short tau inversion recovery may be favored for enhanced anatomic contrast depiction in brain imaging. No benefit of the inclusion of a fat-suppressed T2-FLAIR sequence was found.

Preoperative imaging of superficially located glioma resection using short inversion-time inversion recovery images in high-field magnetic resonance imaging

OBJECTIVES

Short inversion-time inversion recovery (STIR) is the only magnetic resonance imaging (MRI) sequence able to produce high contrast images of both brain-CSF and gray matter-white matter in the central nervous system. The aim of the present study is to evaluate the effectiveness of STIR in imaging tumor involvement of the cortical surface and intra-axial structures, its usefulness in the resection of superficially located gliomas.

PATIENTS AND METHODS

In this study, we perform conventional MRI (1.5 T) and STIR (3.0 T) before surgery in 10 patients with superficially located glioma. We estimate the spatial relationship between the tumor bulk, the adjacent cortical surface and intra-axial structures on T2WI (1.5 T) and STIR (3.0 T). STIR findings are applied to resection of the tumor in each case.

RESULTS

For all patients, STIR provided more satisfactory images than T2WI of both the cortical surface structures and intra-axial structures surrounding the tumor. During surgery, the clear demonstration of cortical surface structures on preoperative STIR images assisted in determining tumor location and the sulci to be split for the trans-sulcal approach for patients whose cortex was normal in colour. Clear contrast on STIR between the tumor margin and peritumoral edema was useful for tumor resection.

CONCLUSION

STIR is able to demonstrate anatomical details of the cortical surface and intra-axial structures of the brain and is therefore suitable for the preoperative evaluation of superficially located gliomas.

Three-dimensional anisotropy contrast imaging of pontine gliomas: 2 case reports

BACKGROUND

Magnetic resonance imaging can provide a preoperative diagnosis of pontine glioma, but the findings sometimes do not correspond with the clinical symptoms. We describe 2 cases of pontine gliomas who did not present with motor and sensory disturbance.

CASE REPORT

Three-dimensional anisotropy contrast (3DAC) imaging was used to assess the neuronal tracts in 2 patients with pontine gliomas. Conventional MR imaging depicted markedly abnormal findings of abnormally high or heterogeneous signal intensity in the pons in 2 cases. In contrast, 3DAC imaging obviously showed the corticospinal and spinothalamic tracts and cerebellar peduncles without destruction by tumors.

CONCLUSION

Three-dimensional anisotropy contrast imaging provides more information about damage to the neuronal tracts in cases of pontine gliomas than other MR imaging techniques. This technique may be used for preoperative mapping of the tumor and its relationship to the tracts, thus, providing an accurate road map for tumor resection.