"Tumoral pseudoblush" identified within gliomas at high-spatial-resolution ultrahigh-field-strength gradient-echo MR imaging corresponds to microvascularity at stereotactic biopsy

Abstract

Purpose: To use directed biopsy sampling to determine whether microvascular assessment within gliomas, by means of ultrahigh-field-strength high-spatial-resolution gradient-echo (GRE) magnetic resonance (MR) imaging at 8 T, correlates with histopathologic assessment of microvascularity.

Materials and methods: The study was institutional review board approved and HIPAA compliant. Informed consent was obtained. Thirty-five subjects with gliomas underwent 8-T and 80-cm MR imaging by using a GRE sequence (repetition time, 600-750 msec; echo time, 10 msec; in-plane resolution, 196 mm). Haphazardly arranged serpentine low-signal-intensity structures, often associated with areas of low signal intensity within the tumor bed ("tumoral pseudoblush") at MR imaging, were presumed to be related to tumoral microvascularity. Microvessel density (MVD) and microvessel size (MVS) ranked with a semiquantitative three-tier scale (high, medium, and low) relative to cortical penetrating veins were assessed from regions of interest identified at MR imaging and were compared with a similar assessment of stereotactic biopsy specimens by using Kendall τb. Tumor grade (high vs low) was compared with ultrahigh-field-strength high-resolution GRE MR analysis by using Pearson χ2. Discrepancies between 8-T and histopathologic assessment were identified and analyzed.

Results: Ultrahigh-field-strength high-resolution GRE MR imaging and histopathologic assessment concurred for MVS (P<.0001) and MVD (P<.0001). World Health Organization classification tumor grade was associated with number (P<.0005) and size (P<.0005) of foci of microvascularity within the tumor bed at 8-T MR imaging. Radiation-induced microvessel hyalinosis mimicked tumor microvascularity at 8-T MR imaging. Potential confounders could result from radiofrequency inhomogeneity and displaced normal microvasculature.

Conclusion: Microvascularity identified as a tumoral pseudoblush at ultrahigh-field-strength high-resolution GRE MR imaging without contrast material shows promise as a marker for increased tumoral microvascularity.

© RSNA, 2012.

Figures

Figure 1a:

(a) Axial gadolinium-enhanced T1-weighted MR image in 24-year-old man with history of blurry vision, headaches, and papilledema associated with an intraventricular mass. (b) Axial ultrahigh-field-strength high-resolution GRE MR image shows stereotactic biopsy site of a focus suggestive of high microvascularity that was shown at histopathologic assessment to represent a high degree of microvascular density, with microvessels similar in size to cortical draining veins within a WHO grade II central neurocytoma. (c) MR image shows serpentine flow voids and surrounding signal intensity loss within the biopsy site (tumoral pseudoblush). (d) Ultrahigh-field-strength high-resolution GRE MR image from an adjacent section within the tumor 2 cm beneath the biopsy site shows associated enlarged tributary to the thalamostriate vein (arrowheads) coursing medial to lateral in and out of the imaging plane. This information can assist stereotactic biopsy planning because damage to this vessel can result in substantial bleeding.

Figure 1b:

(a) Axial gadolinium-enhanced T1-weighted MR image in 24-year-old man with history of blurry vision, headaches, and papilledema associated with an intraventricular mass. (b) Axial ultrahigh-field-strength high-resolution GRE MR image shows stereotactic biopsy site of a focus suggestive of high microvascularity that was shown at histopathologic assessment to represent a high degree of microvascular density, with microvessels similar in size to cortical draining veins within a WHO grade II central neurocytoma. (c) MR image shows serpentine flow voids and surrounding signal intensity loss within the biopsy site (tumoral pseudoblush). (d) Ultrahigh-field-strength high-resolution GRE MR image from an adjacent section within the tumor 2 cm beneath the biopsy site shows associated enlarged tributary to the thalamostriate vein (arrowheads) coursing medial to lateral in and out of the imaging plane. This information can assist stereotactic biopsy planning because damage to this vessel can result in substantial bleeding.

Figure 1c:

(a) Axial gadolinium-enhanced T1-weighted MR image in 24-year-old man with history of blurry vision, headaches, and papilledema associated with an intraventricular mass. (b) Axial ultrahigh-field-strength high-resolution GRE MR image shows stereotactic biopsy site of a focus suggestive of high microvascularity that was shown at histopathologic assessment to represent a high degree of microvascular density, with microvessels similar in size to cortical draining veins within a WHO grade II central neurocytoma. (c) MR image shows serpentine flow voids and surrounding signal intensity loss within the biopsy site (tumoral pseudoblush). (d) Ultrahigh-field-strength high-resolution GRE MR image from an adjacent section within the tumor 2 cm beneath the biopsy site shows associated enlarged tributary to the thalamostriate vein (arrowheads) coursing medial to lateral in and out of the imaging plane. This information can assist stereotactic biopsy planning because damage to this vessel can result in substantial bleeding.

Figure 1d:

(a) Axial gadolinium-enhanced T1-weighted MR image in 24-year-old man with history of blurry vision, headaches, and papilledema associated with an intraventricular mass. (b) Axial ultrahigh-field-strength high-resolution GRE MR image shows stereotactic biopsy site of a focus suggestive of high microvascularity that was shown at histopathologic assessment to represent a high degree of microvascular density, with microvessels similar in size to cortical draining veins within a WHO grade II central neurocytoma. (c) MR image shows serpentine flow voids and surrounding signal intensity loss within the biopsy site (tumoral pseudoblush). (d) Ultrahigh-field-strength high-resolution GRE MR image from an adjacent section within the tumor 2 cm beneath the biopsy site shows associated enlarged tributary to the thalamostriate vein (arrowheads) coursing medial to lateral in and out of the imaging plane. This information can assist stereotactic biopsy planning because damage to this vessel can result in substantial bleeding.

Figure 2a:

(a) Axial ultrahigh-field-strength high-resolution GRE MR image in 58-year-old woman with left leg numbness and weakness due to a right parietal lobe glioblastoma near the central sulcus. Box indicates area enlarged in (b) MR image that shows stereotactic biopsy sites where specimens were taken from foci (A, B, C) outlined by arrowheads. (c) At histopathologic assessment, focus A was found to harbor low microvascularity(not shown). Focus B from an area of tumoral pseudoblush represented an area of high microvascular density and large microvascular size with endothelial proliferation (arrowheads). (Hema-toxylin-eosin stain; original magnification, ×200.) Focus C revealed hemorrhagic necrosis (not shown).

Figure 2b:

(a) Axial ultrahigh-field-strength high-resolution GRE MR image in 58-year-old woman with left leg numbness and weakness due to a right parietal lobe glioblastoma near the central sulcus. Box indicates area enlarged in (b) MR image that shows stereotactic biopsy sites where specimens were taken from foci (A, B, C) outlined by arrowheads. (c) At histopathologic assessment, focus A was found to harbor low microvascularity(not shown). Focus B from an area of tumoral pseudoblush represented an area of high microvascular density and large microvascular size with endothelial proliferation (arrowheads). (Hema-toxylin-eosin stain; original magnification, ×200.) Focus C revealed hemorrhagic necrosis (not shown).

Figure 2c:

(a) Axial ultrahigh-field-strength high-resolution GRE MR image in 58-year-old woman with left leg numbness and weakness due to a right parietal lobe glioblastoma near the central sulcus. Box indicates area enlarged in (b) MR image that shows stereotactic biopsy sites where specimens were taken from foci (A, B, C) outlined by arrowheads. (c) At histopathologic assessment, focus A was found to harbor low microvascularity(not shown). Focus B from an area of tumoral pseudoblush represented an area of high microvascular density and large microvascular size with endothelial proliferation (arrowheads). (Hema-toxylin-eosin stain; original magnification, ×200.) Focus C revealed hemorrhagic necrosis (not shown).

Figure 3a:

Data in 55-year-old woman with visual changes and headache. (a, b) Axial ultrahigh-field-strength high-resolution GRE MR images reveal foci with a high degree of microvascular density and large size (arrowheads in b). Box indicates area enlarged in b. (c) Histopathologic findings show that stereotactic biopsy of this focus revealed a high degree of microvascular density and large microvessels with endothelial proliferation (arrowheads), which corroborates MR imaging findings. (Reticulin stain; original magnification, ×200.)

Figure 3b:

Data in 55-year-old woman with visual changes and headache. (a, b) Axial ultrahigh-field-strength high-resolution GRE MR images reveal foci with a high degree of microvascular density and large size (arrowheads in b). Box indicates area enlarged in b. (c) Histopathologic findings show that stereotactic biopsy of this focus revealed a high degree of microvascular density and large microvessels with endothelial proliferation (arrowheads), which corroborates MR imaging findings. (Reticulin stain; original magnification, ×200.)

Figure 3c:

Data in 55-year-old woman with visual changes and headache. (a, b) Axial ultrahigh-field-strength high-resolution GRE MR images reveal foci with a high degree of microvascular density and large size (arrowheads in b). Box indicates area enlarged in b. (c) Histopathologic findings show that stereotactic biopsy of this focus revealed a high degree of microvascular density and large microvessels with endothelial proliferation (arrowheads), which corroborates MR imaging findings. (Reticulin stain; original magnification, ×200.)

Figure 4a:

(a) Axial ultrahigh-field-strength high-resolution GRE MR image shows area of profound signal intensity loss due to susceptibility effect within a glioblastoma (arrowheads). (b) Histopathologic findings show that stereotactic biopsy of this area of signal intensity loss revealed hemorrhagic necrosis associated with fibrinoid change and occluded vessels. (Hematoxylin-eosin stain; original magnification, ×200.)

Figure 4b:

(a) Axial ultrahigh-field-strength high-resolution GRE MR image shows area of profound signal intensity loss due to susceptibility effect within a glioblastoma (arrowheads). (b) Histopathologic findings show that stereotactic biopsy of this area of signal intensity loss revealed hemorrhagic necrosis associated with fibrinoid change and occluded vessels. (Hematoxylin-eosin stain; original magnification, ×200.)