Early experience of pre- and post-contrast 7.0T MRI in brain tumors

Abstract

We investigated the safety and clinical applicability of 7.0 Tesla (T) brain magnetic resonance imaging (MRI) in patients with brain tumors. Twenty-four patients with intraaxial or extraaxial brain tumors were enrolled in this study. 7.0T MRIs of T2*-weighted axial and T1-weighted coronal or sagittal images were obtained and compared with 1.5T brain MRIs. The T2*-weighted images from 7.0T brain MRI revealed detailed microvasculature and the internal contents of supratentorial brain tumors better than that of 1.5T brain MRI. For brain tumors located in parasellar areas or areas adjacent to major cerebral vessels, flow-related artifacts were exaggerated in the 7.0T brain MRIs. For brain tumors adjacent to the skull base, susceptibility artifacts in the interfacing areas of the paranasal sinus and skull base hampered the aquisition of detailed images and information on brain tumors in the 7.0T brain MRIs. This study shows that 7.0T brain MRI can provide detailed information on the intratumoral components and margins in supratentorial brain tumors. Further studies are needed to develop refined MRI protocols for better images of brain tumors located in the skull base, parasellar, and adjacent major cerebrovascular structures.

Keywords: 7.0 Tesla; Brain Neoplasms; Clinical Applicability; Magnetic Resonance Imaging; Safety.

Fig. 1

1.5T and 7.0T MRI for pituitary adenoma. The pre- and post-contrast T1-weighted coronal images from 1.5T (A, B) and 7.0T brain MRI (C, D) in a patient with pituitary adenoma (Patient Number 3 in Table 2). Precontrast (A) and postcontrast (B) T1-weighted sellar images from 1.5T brain MRI show a well-enhancing intrasellar mass lesion located on the left side of the sellar turcica with a deviated pituitary stalk to the right side. In contrast, the precontrast (C) and postcontrast (D) T1-weighted sellar images from 7.0T brain MRI do not provide a clear margin of the sellar mass lesion and its margin with the adjacent neurovascular structures in the left cavernous sinus. The flow related artifacts of both internal carotid arteries (ICAs) in the cavernous sinus as well as the susceptibility artifacts coming from the interface of the air-density area of the paranasal sinus and bony structures of skull base are noticeable around the surrounding structures of the pituitary adenoma.

Fig. 2

1.5T and 7.0T MRI for chordoma. The T2-weighted axial and contrast-enhancing T1-weighted sagittal images from 1.5T (A, B) and 7T brain MRI (C, D) in a patient with a chordoma (Patient Number 22 in Table 2). T2-weighted axial (A) and postcontrast (B) T1-weighted sagittal images from 1.5T brain MRI show an irregularly enhancing multi-loculated mass lesion located in the clivus extending into the sphenoid sinus. In contrast, T2-weighted axial (C) and postcontrast (D) T1-weighted sagittal images from 7.0T brain MRI do not provide a clear margin between the sellar mass lesion and the adjacent neurovascular structures in the skull base area. The flow related artifacts of both ICAs in the cavernous sinus as well as the susceptibility artifacts coming from the interface of the air-density area of the paranasal sinus and bony structures of skull base are noticeable around the surrounding structures of the chordoma.

Fig. 3

1.5T and 7.0T MRI for central neurocytoma. T2-weighted axial and post-contrast T1-weighted coronal images from 1.5T brain MRI (A, B) and T2-weighted axial and post-contrast T1-weighted coronal images from 7.0T brain MRI (C, D) in a patient with a central neurocytoma (Patient Number 7 in Table 2). A T2-weighted image from 1.5T brain MRI (A) shows the vascularity of the brain tumor & draining veins on the surface of the tumor located in the central portion of the lateral ventricles. Post-contrast coronal images from 1.5T brain MRI (B) demonstrate an intraventricular enhancing mass lesion mainly located in the left lateral ventricle extending into the right lateral ventricle. In contrast to the 1.5T MRI, T2 axial images from 7.0T brain MRI (C) show a clearer image of the tumor margin between the tumor and its surrounding structures and the interface with the thalamo-caudate nucleus. A post-contrast T1-weighted coronal image from 7.0T brain MRI (D) shows better contrast between the white and gray matter in the cortical brain surface in contrast to the 1.5T brain MRI. However, the flow from the deep draining veins of the internal cerebral veins and both transverse sinuses results in linear artifacts crossing over the midline in the post-contrast T1-weighted coronal images from 7.0T brain MRI. In addition, chemical shift artifacts caused by the interface between the cerebellar hemisphere and petrous bone hampers the signal-to-noise ratio of the post-contrast T1-weighted coronal image from 7T brain MRI.

Fig. 4

1.5T and 7.0T MRI for cavernous hemangioma. T2-weighted axial and post-contrast T1-weighted coronal images from 1.5T brain MRI (A, B) and T2-weighted axial and post-contrast T1-weighted coronal images from 7.0T brain MRI (C, D) in a patient with a cavernous hemangioma (Patient Number 20 in Table 2). Compared to the T2-weighted axial image from 1.5T brain MRI (A), the hemorrhagic contents in different stages of the cavernous hemangioma are more clearly visualized in the T2-weighted axial images from the 7T brain MRI (C). Compared to the 1.5T brain MRI (B), the post-contrast T1-weighted coronal images from the 7.0T brain MRI (D) show a sharper margin between the white matter and cavernous hemangioma in the brain parenchyma. However, the flow from both the middle cerebral arteries causes flow-related linear artifact crossing over the midline in the post-contrast T1-weighted coronal images from the 7T brain MRI (D).

Fig. 5

1.5T and 7.0T MRI for metastatic brain tumor of non-small cell lung carcinoma. T2-weighted axial and post-contrast T1-weighted coronal images from 1.5T brain MRI (A, B) and T2*-weighted axial and post-contrast T1-weighted coronal images from 7.0T brain MRI (C, D) in a patient with a metastatic brain tumor of non-small cell lung carcinoma (Patient Number 23 in Table 2). Compared to the 1.5T brain MRI (A), the T2*-weighted axial images from the 7.0T brain MRI (C) show a clearer image of the tumor margin between the tumor and its surrounding white matter fiber projections such as left optic radiation. Compared to the 1.5T brain MRI (B), the post-contrast T1-weighted coronal images from the 7.0T brain MRI (D) show sharply demarcated enhancing tumor lesions with distinct margins from the normal white matter.

Fig. 6

1.5T and 7.0T MRI for glioblastoma. T2-weighted axial and post-contrast T1-weighted coronal images from 1.5T brain MRI (A, B) and T2-weighted axial and post-contrast T1-weighted coronal images from 7.0T brain MRI (C, D) in a patient with a glioblastoma (Patient Number 8 in Table 2). Compared to the T2-weighted axial images from the 1.5T brain MRI (A), the flow related artifacts caused by the posterior circulation arteries such as the basilar artery, superior cerebellar artery, or posterior cerebral artery are exaggerated crossing over the midline in the T2-weighted axial image from the 7.0T brain MRI (C). The post-contrast T1-weighted coronal images from the 1.5T (B) and 7.0T (D) brain MRI show a small enhancing nodule of recurrent glioblastoma in the right temporal lobe.