Fusion imaging for intra-operative ultrasound-based navigation in neurosurgery

Abstract

The major shortcoming of image-guided navigation systems is the use of presurgically acquired image data, which does not account for intra-operative changes such as brain shift, tissue deformation and tissue removal occurring during the surgical procedure. Intra-operative ultrasound (iUS) is becoming widely used in neurosurgery but they lack orientation and panoramic view. In this article, we describe our procedure for US-based real-time neuro-navigation during surgery. We used fusion imaging between preoperative magnetic resonance imaging (MRI) and iUS for brain lesion removal in 67 patients so far. Surgical planning is based on preoperative MRI only. iUS images obtained during surgery are fused with the preoperative MRI. Surgery is performed under intra-operative US control. Relying on US imaging, it is possible to recalibrate navigated MRI imaging, adjusting distortion due to brain shift and tissue resection, continuously updating the two modalities. Ultrasound imaging provides excellent visualization of targets, their margins and surrounding structures. The use of navigated MRI is helpful in better understanding cerebral ultrasound images, providing orientation and panoramic view. Intraoperative US-guided neuro-navigation adjustments are very accurate and helpful in the event of brain shift. The use of this integrated system allows for a true real-time feedback during surgery.Keywords Navigation Á Brain shift Á Intraoperative imaging Á Ultrasound Á Brain tumor Á Fusion imaging Sommario Il principale difetto della neurochirurgia guidata da immagini è il basarsi su immagini acquisite prima dell'intervento, che per ovvie ragioni non possono tenere conto di fenomeni intra-operatori come il brain-shift, la deformazione dei tessuti e l'asportazione di tessuto patologico. L'ecografia intra-operatoria (iUS) sta acquisendo sempre maggior rilevanza in ambito neurochirurgico ma è limitata dalla difficoltosa interpretazione dell'orientamento delle immagini e dalla scarsa panoramicità. In questo articolo descriviamo la nostra tecnica di neuronavigazione real-time basata sull'ecografia intra-operatoria. Fino ad ora abbiamo impiegato la fusione d'immagini tra la risonanza magnetica (MRI) pre-operatoria e l'iUS in 67 pazienti affetti da neoplasie cerebrali. La pianificazione dell'intervento e l'approccio chirurgico è basata sulla (MRI) pre-operatoria mentre l'intervento è guidato dall'iUS. Basandosi sull'iUS è possibile correggere la calibrazione delle immagini (MRI) pre-operatorie correggendo il brain-shift, aggiornando continuamente le due modalità. L'ecografia intra-operatoria permette una eccellente identificazione dei target, dei margini e delle strutture circostanti. L'uso del navigatore basato su (MRI) pre-operatoria è utile nella comprensione delle immagini ecografiche soprattutto per quanto riguarda l'orientazione e la visione panoramica. Le correzione del sistema di neuronavigazione basate sull'iUS sono accurate e utili nel caso di fenomeni intra-operatori come il brain-shift, la deformazione dei tessuti ...

Identification of residual tumor with intraoperative contrast-enhanced ultrasound during glioblastoma resection

“…This finding is possible using a navigated iUS device. 5,15,[21][22][23]27,32 Anyway, this solution has major limitations because of the impossibility of taking into account not brain deformation but only brain shift. For this reason the comparison between iUS and preoperative MRI can only be suggestive.…”

“…20,30 During surgery we performed multiple standard Bmode scans. Compensation for brain shift was accomplished using the fine-tuning option as previously described in other papers from our group, 21,22 to maintain the surgical volume.…”

Fusion of Intraoperative 3D B-mode and Contrast-Enhanced Ultrasound Data for Automatic Identification of Residual Brain Tumors

“…For instance, the CT-MR fusion images were used by Nemec et al [31] for supporting the surgeon to improve the surgical performance of temporal bone tumors. Furthermore, Prada et al [32] presented the fusion imaging between preoperative MRI and iUS for intra-operative ultrasound-based navigation in the context of brain tumor removal. The combination of the MRI, characterized by good spatial resolution and a wide field of view, and the iUS that provides real-time status of the brain enables improvement of surgical outcomes.…”

Editorial: Turning fluorescence into black and white

“…Through a number of retrospective observational studies, EOR has been identified as a predictor of survival in newly diagnosed 6 and recurrent 1 high-grade gliomas. In general, the strongest evidence for this association comes with complete resection, 4,8 although one well-known study demonstrated a benefit, at least in newly diagnosed glioblastoma, of any resection greater than 78%. 6 Others have demonstrated a continuous nonlinear association with EOR and survival, 5 suggesting that even a less rigid resection threshold might be adoptable for these tumors.…”

“…Other strategies used to address the limitations of neuronavigation include intraoperative MRI 6 and ultrasonography. 4 With the advent of fluorescence-guided microscopic surgery, we are at an important evolutionary point in overcoming the limitations of neuronavigation.…”