Table 1.
Patient characteristics.
Figure 1.
Pattern of contrast-enhancement (CE) on magnetic resonance imaging (MRI) of gliomas with non-significant CE.
T1-weighted contrast-enhanced MR images demonstrate examples of gliomas with (a) no visible ( = none) CE, (c) unspecific ( = patchy/faint) CE and (e) a small regional ( = focal) CE in an otherwise non-enhancing tumor. (b,d,f) T2-weighted MR images show the corresponding hyperintense glioma lesions.
Table 2.
All gliomas of the current study (n = 59): Assessment of the amount of contrast-enhancement on magnetic resonance imaging, WHO tumor grade, histopathological WHO criteria and proliferation rate in PpIX focally positive versus negative gliomas.
Figure 2.
Example of 5-ALA application in a left temporal glioma with non-significant contrast-encencement (CE) on magnetic resonance imaging (MRI).
(a) Preoperative contrast-enhanced T1-weighted MR images show patchy/faint CE and (g) hyperintensity on FLAIR sequences. (b) The intratumoral area outside the region of maximum positron emission tomography (PET) tracer uptake verified by the intraoperative navigation system (c) appeared as whitish glioma tissue under the surgical microscope, (d) with no detectable PpIX fluorescence. (e) The corresponding histopathology reveals low-grade glioma tissue according to the WHO criteria in the H&E stain (f) with a low proliferation rate (MIB-1: <10%). (h) In contrast, the intratumoral area inside the region of maximum PET tracer uptake (i) showed similar glioma tissue appearance in the microscopic view, (j) but revealed strong PpIX fluorescence under violet-blue excitation light. (k) The corresponding histopathology reveals high-grade glioma tissue in accordance with an anaplastic focus according to the WHO criteria in the H&E stain (l) with a high proliferation rate (MIB-1: 32%). The final histopathological diagnosis revealed a focally anaplastic astrocytoma (WHO grade III) and the patient was treated with radiochemotherapy. The width of each histopathological image (e, f, k, l) was 300 micrometers (µm).
Table 3.
Predictive relationship of visible PpIX fluorescence and anaplastic histology.
Table 4.
All PpIX fluorescence positive tumors (n = 27): Assessment of histopathological WHO criteria and proliferation rate in PpIX focally positive versus negative intratumoral areas within the same glioma.