Label-free dynamic cell imaging of fresh ex vivo spinal meningiomas: a nine-case optical-pathological correlation study with specimen-level H&E references

Abstract

Spinal meningioma subtype and grade still rest on haematoxylin and eosin (H&E) morphology, but permanent sections become available only after fixation and embedding, and intraoperative assessment of fresh tissue relies mainly on frozen section. Dynamic cell imaging (DCI), a label-free readout from dynamic full-field optical coherence tomography, images unprocessed specimens within minutes. Whether its regional signal corresponds to H&E in spinal meningioma has not been described. We imaged nine fresh ex vivo spinal meningioma specimens by DCI on an active phase modulation-assisted dynamic full-field OCT (APMD-FFOCT) platform. All specimens were transported on ice and imaged at approximately 60 min after resection: eight CNS WHO grade 1 tumours (psammomatous, n = 3; transitional, n = 2; meningothelial, n = 1; not further subtyped, n = 2) and one meningioma, CNS WHO grade 3. Every specimen had a specimen-level H&E reference from the same fragment, without pixel-level co-registration. Six author-defined DCI features were recorded descriptively against conventional H&E, Ki-67, and available immunohistochemistry. Selected DCI-derived virtual H&E renderings were compared visually with conventional H&E but were not used as diagnostic references. Diagnostic accuracy, blinded subtype assignment, reader agreement, and ROC analysis were not assessed. In all three psammomatous cases, DCI showed round or concentric signal-poor foci within whorl-like regions; specimen-level H&E showed corresponding psammoma bodies and meningothelial whorls. Both transitional cases showed mixed fascicular and whorl-like patterns; meningothelial case and the two grade 1 cases without a specific histological subtype showed sheet-like, lobular, or mixed patterns. Dark fibrillar DCI signal was compatible with collagenous stroma. The grade 3 case showed disorganised hypercellular texture without whorls and a Ki-67 index of 70%; Ki-67 was 3–10% in grade 1 tumours. Virtual H&E renderings displayed selected DCI fields in an H&E-like colour space and were treated only as visual aids. In nine fresh ex vivo spinal meningiomas, DCI showed regional correspondence with conventional H&E for cellular architecture, collagenous stroma, and psammomatous calcification, with specimen-level H&E available for every case. These descriptive, unblinded findings do not replace histopathology, and subtype and grade assignment remain dependent on permanent pathology. The findings support prospective workflow testing of DCI as a fresh-tissue survey method for representative sampling before permanent pathology, ancillary testing, molecular studies, and biobanking.