Inadequate margins continue to occur frequently in patients who undergo surgical resection of a tumor, suggesting that current intraoperative methods are not sufficiently reliable in determining the margin status. This clinical demand has inspired the development of many novel imaging techniques that could help surgeons with intraoperative margin assessment. This systematic review provides an overview of novel imaging techniques for intraoperative margin assessment in surgical oncology, and reports on their technical properties, feasibility in clinical practice and diagnostic accuracy. PubMed, Embase, Web of Science and the Cochrane library were systematically searched (2013)(2014)(2015)(2016)(2017)(2018) for studies reporting on imaging techniques for intraoperative margin assessment. Patient and study characteristics, technical properties, feasibility characteristics and diagnostic accuracy were extracted. This systematic review identified 134 studies that investigated and developed 16 groups of techniques for intraoperative margin assessment: fluorescence, advanced microscopy, ultrasound, specimen radiography, optical coherence tomography, magnetic resonance imaging, elastic scattering spectroscopy, bio-impedance, X-ray computed tomography, mass spectrometry, Raman spectroscopy, nuclear medicine imaging, terahertz imaging, photoacoustic imaging, hyperspectral imaging and pH measurement. Most studies were in early developmental stages (IDEAL 1 or 2a, n = 98); high-quality stage 2b and 3 studies were rare. None of the techniques was found to be clearly superior in demonstrating high feasibility as well as high diagnostic accuracy. In conclusion, the field of imaging techniques for intraoperative margin assessment is highly evolving. This review provides a unique overview of the opportunities and limitations of the currently available imaging techniques.

Purpose To evaluate the feasibility of ex vivo 7T MRI to assess surgical margins (SMs) and pseudocapsule (PC) features after partial nephrectomy (PN). Materials and methods In this prospective, IRB-approved study, seven patients undergoing a PN for nine tumours between November 2014 and July 2015 were included for analysis after obtaining informed consent. MRI of the specimen was acquired using a 7T small bore scanner. The imaging protocol consisted of anatomical T1-, T2-and diffusion-weighted imaging. After formalin fixation, specimens were cut for pathology work-up in the same orientation as the MR images were obtained. The entire specimen was processed into H&E slides that were digitally scanned, annotated and correlated with radiological findings for negative SMs, PC presence, PC continuity and extra-PC-extension (EPCE). Sensitivity and specificity of MRI for assessment of these endpoints were calculated. Results The sensitivity and specificity for assessment of the SM were 100% and 75%, respectively. Two falsepositive outcomes were reported, both in case of EPCE and a SM ≤0.5 mm. For the presence of a PC, sensitivity and specificity were 100% and 33%, respectively. Two false-positive scans with anatomical structures mimicking the presence of a PC occurred. If a PC was present, continuity and EPCE were assessed with a sensitivity and specificity of 75% and 100% and 67% and 100%, respectively. Conclusion Ex vivo 7T MRI is a feasible tool for perioperative evaluation of SMs, and if present, PC features after PN. This may facilitate maximal sparing of renal parenchyma without compromising oncological outcomes. Key Points • Ex vivo MRI may contribute to improvement of negative surgical margins during partial nephrectomy.• Due to the assessment of surgical margins within a limited time span from obtaining the partial nephrectomy specimen, surgery for more complex tumours is possible with maximum sparing of healthy renal parenchyma without compromising oncological outcomes.• The intra operative assessment of pseudocapsule continuity along the resection margin enables maximal sparing of healthy renal parenchyma without delayed diagnosis of incomplete resection.

Background Current intraoperative methods of visual inspection and tissue palpation by the surgeon, and frozen section analysis cannot reliably prevent inadequate surgical margins in patients treated for oral squamous‐cell carcinoma (OSCC). This study assessed feasibility of MRI for the assessment of surgical resection margins in fresh OSCC specimens. Methods Ten consecutive tongue specimens containing OSCC were scanned using 3 T clinical whole‐body MRI. Two radiologists independently annotated OSCC location and minimal tumor‐free margins. Whole‐mount histology was the reference standard. Results The positive predictive values (PPV) and negative predictive values (NPV) for OSCC localization were 96% and 75%, and 87% and 79% for reader 1 and 2, respectively. The PPV and NPV for identification of margins <5 mm were 38% and 91%, and 5% and 87% for reader 1 and 2, respectively. Conclusions mri accurately localized OSCC with high inter‐reader agreement in fresh OSCC specimens, but it seemed not yet feasible to accurately assess the surgical margin status.

Purpose To validate a simulation environment for virtual planning of percutaneous cryoablation of renal tumors. Materials and Methods Prospectively collected data from 19 MR-guided procedures were used for validation of the simulation model. Volumetric overlap of the simulated ablation zone volume (Σ) and the segmented ablation zone volume (S; assessed on 1-month follow-up scan) was quantified. Validation metrics were DICE Similarity Coefficient (DSC; the ratio between twice the overlapping volume of both ablation zones divided by the sum of both ablation zone volumes), target overlap (the ratio between the overlapping volume of both ablation zones to the volume of S; low ratio means S is underestimated), and positive predictive value (the ratio between the overlapping volume of both ablation zones to the volume of Σ; low ratio means S is overestimated). Values were between 0 (no alignment) and 1 (perfect alignment), a value > 0.7 is considered good. Results Mean volumes of S and Σ were 14.8 cm3 (± 9.9) and 26.7 cm3 (± 15.0), respectively. Mean DSC value was 0.63 (± 0.2), and ≥ 0.7 in 9 cases (47%). Mean target overlap and positive predictive value were 0.88 (± 0.11) and 0.53 (± 0.24), respectively. In 17 cases (89%), target overlap was ≥ 0.7; positive predictive value was ≥ 0.7 in 4 cases (21%) and < 0.6 in 13 cases (68%). This indicates S is overestimated in the majority of cases. Conclusion The validation results showed a tendency of the simulation model to overestimate the ablation effect. Model adjustments are necessary to make it suitable for clinical use.

Background The shift from open to minimally invasive procedures with growing complexity has increased the demand for advanced intraoperative medical technologies. The hybrid operating room (OR) combines the functionality of a standard OR with fixed advanced imaging systems to facilitate minimally invasive image-guided procedures. Objective This systematic scoping review provides an overview of the use of the hybrid OR over the years, and reports on the encountered advantages and challenges. Methods We conducted a systematic search in PubMed, Embase, Web of Science, and Cochrane library databases for studies that described procedures being performed with the aid of 3D imaging in the hybrid OR. Results The search identified 123 studies that described 44 distinct procedures, divided over nine clinical disciplines. The number of studies increased from two in 2010 to 15 in the first five months of 2020. Ninety-nine (80%) of the studies described how 3D imaging was performed in the hybrid OR; 95 (96%) used cone-beam CT; four (4%) used multi-detector CT. Advantages and challenges of the hybrid OR were described in 94 (76%) and 34 (35%) studies, respectively. The most frequently reported advantage of using a hybrid OR is the achievement of more accurate treatment results, whereas elongation of the procedure time is the most important challenge, followed by an increase in radiation dose. Conclusion In conclusion, the growing number of clinical disciplines that uses the hybrid OR shows its wide functionality. To optimize its use, future comparative studies should be conducted to investigate which procedures really benefit from being performed in the hybrid OR.