Intraoperative imaging of oral-maxillofacial lesions using optical coherence tomography

Histopathological examination is still the gold standard for diagnoses of oral-maxillofacial lesions,but it is invasive and time-consuming.Optical coherence tomography(OCT)provides a kind of noninvasive,label-free,real-time and high-resolution imaging technology.In this study,in order to assess the feasibility of OCT in oral clinical application,fresh excised tissue specimens from 59 patients undergoing oral-maxillofacial surgery were imaged in detail by using a benchtop sweptsource OCT system.It is shown that different lesions or tissues can be obviously distinguished based on their different microstructural features in OCT images,and the features are similar to those of their corresponding histopathological images.It is proven that OCT has great feasibility and potential as a diagnostic aid for surgeons in oral medicine.

Physiology of in-situ arterial revascularization in coronary artery bypass grafting: Preoperative,intraoperative and postoperative factors and influences

Surgical revascularization with coronary artery bypass grafting(CABG) has become established as the most effective interventional therapy for patients with moderately severe and severe stable ischemic heart disease(SIHD). This recommendation is based on traditional 5-year outcomes of mortality and avoidance of myocardial infarction leading to reintervention and/or cardiac death. However, these results are confounded in that they challenge the traditional CABG surgical tenets of completeness of anatomic revascularization, the impact of arterial revascularization on late survival, and the lesser impact of secondary prevention following CABG on late outcomes. Moreover, the emergence of physiologic-based revascularization with percutaneous cardiovascular intervention as an alternative strategy for revascularization in SIHD raises the question of whether there are similar physiologic effects in CABG. Finally, the ongoing ISCHEMIA trial is specifically addressing the importance of the physiology of moderate or severe ischemia in optimizing therapeutic interventions in SIHD. So it is time to address the role that physiology plays in surgical revascularization. The long-standing anatomic framework for surgical revascularization is no longer sufficient to explain the mechanisms for short-term and long-term outcomes in CABG. Novel intraoperative imaging technologies have generated important new data on the physiologic blood flow and myocardial perfusion responses to revascularization on an individual graft and global basis. Long-standing assumptions about technical issues such as competitive flow are brought into question by real-time visualization of the physiology of revascularization. Our underestimation of the impact of Guideline Directed Medical Therapy, or Optimal Medical Therapy, on the physiology of preoperative SIHD, and the full impact of secondary prevention on post-intervention SIHD, must be better understood. In this review, these issues are addressed through the perspective of multi-arterial revascularization in CABG, which is emerging(after 30 years) as the "standard of care" for CABG. In fact, it is the physiology of these arterial grafts that is the mechanism for their impact on long-term outcomes in CABG. Moreover, a better understanding of all of these preoperative, intraoperative and postoperative components of the physiology of revascularization that will generate the next, more granular body of knowledge about CABG, and enable surgeons to design and execute a better surgical revascularization procedure for patients in the future.

The application of indocyanine green in guiding prostate cancer treatment

Objective:Indocyanine green(ICG)with near-infrared fluorescence absorption is approved by the United States Food and Drug Administration for clinical applications in angiography,blood flow evaluation,and liver function assessment.It has strong optical absorption in the near-infrared region,where light can penetrate deepest into biological tissue.We sought to review its value in guiding prostate cancer treatment.Methods:All related literature at PubMed from January 2000 to December 2020 were reviewed.Results:Multiple preclinical studies have demonstrated the usefulness of ICG in identifying prostate cancer by using different engineering techniques.Clinical studies have demonstrated the usefulness of ICG in guiding sentinel node dissection during radical prostatectomy,and possible better preservation of neurovascular bundle by identifying landmark prostatic arteries.New techniques such as adding fluorescein in additional to ICG were tested in a limited number of patients with encouraging result.In addition,the use of the ICG was shown to be safe.Even though there are encouraging results,it does not carry sufficient sensitivity and specificity in replacing extended pelvic lymph node dissection during radical prostatectomy.Conclusion:Multiple preclinical and clinical studies have shown the usefulness of ICG in identifying and guiding treatment for prostate cancer.Larger randomized prospective studies are warranted to further test its usefulness and find new modified approaches.

SEGMENTATION AND CORRELATION OF OPTICAL COHERENCE TOMOGRAPHY AND X-RAY IMAGES FOR BREAST CANCER DIAGNOSTICS

Pre-operative X ray mammography and int raoperative X-ray specimen radiography are routinely used to identify breast cancer pathology.Recent advances in optical coherence tomography(OCT)have enabled its 1use for the intraoperative assessment of surgical margins during breast cancer surgery.While each modality offers distinct contrast of normal and pathological features,there is an essential need to correlate image based features between the two modalities to take adv antage of the diagnostic capabilities of each technique.We compare OCT to X-ray images of resected human breast tissue and correlate different tissue features between modalities for future use in real-tine intraoperative OCT imaging.X ray imaging(specimen radiography)is currently used during surgical breast cancer procedures to verify tumor margins,but cannot image tissue in situ.OCT has the potential to solve this problem by providing intrao-perative imaging of the resected specimen as well as the in situ tumor cavity.OCT and micro-CT(X-ray)images are automatically segmented using different computational approaches,and quantitatively compared to determine the ability of these algorithms to automat ically differentiate regions of adipose tissue from tumor.Furthermore,two-dimensional(2D)and three-dimensional(3D)results are compared.These correlations,combined with real-time intraoperative OCT,have the potential to identify possible regions of tumor within breast tissue which correlate to tumor regions identified previously on X-ray imaging(mammography or specimen radiography).

Intraoperative reperfusion assessment of human pancreas allografts using hyperspectral imaging(HSI)

Background:The most common causes of early graft loss in pancreas transplantation are insufficient blood supply and leakage of the intestinal anastomosis.Therefore,it is critical to monitor graft perfusion and oxygenation during the early post-transplant period.The goal of our pilot study was to evaluate the utility of hyperspectral imaging(HSI)in monitoring the microcirculation of the graft and adequate perfusion of the intestinal anastomosis during pancreatic allotransplantation.Methods:We imaged pancreatic grafts and intestinal anastomosis in real-time in three consecutive,simultaneous pancreas-kidney transplantations using the TIVITA®HSI system.Further,the intraoperative oxygen saturation(StO_(2)),tissue perfusion(near-infrared perfusion index,NIR),organ hemoglobin index(OHI),and tissue water index(TWI)were measured 15 minutes after reperfusion by HSI.Results:All pancreas grafts showed a high and homogeneous StO_(2)(92.6%±10.45%).Intraoperative HSI analysis of the intestinal anastomosis displayed significant differences of StO_(2)(graft duodenum 67.46%±5.60%vs.recipient jejunum:75.93%±4.71%,P<0.001)and TWI{graft duodenum:0.63±0.09[I(Index)]vs.recipient jejunum:0.72±0.09[I],P<0.001}.NIR and OHI did not display remarkable differences{NIR duodenum:0.68±0.06[I]vs.NIR jejunum:0.69±0.04[I],P=0.747;OHI duodenum:0.70±0.12[I]vs.OHI jejunum:0.68±0.13[I],P=0.449}.All 3 patients had an uneventful postoperative course with one displaying a Banff 1a rejection which was responsive to steroid treatment.Conclusions:Our study shows that contact-free HSI has potential utility as a novel tool for real-time monitoring of human pancreatic grafts after reperfusion,which could improve the outcome of pancreas transplantation.Further investigations are required to determine the predictive value of intraoperative HSI imaging.

Clinical experience of 3T intraoperative magnetic resonance imaging integrated neurosurgical suite in Shanghai Huashan Hospital

Background Intraoperative magnetic resonance imaging （iMRI） dates back to the 1990s and has been successfully applied in neurosurgery but they were low-field iMRI （〈1.0T）. This paper reports the clinical experience with a 3T iMRI-integrated neurosurgical suite in Huashan Hospital, Shanghai, China. Methods From September 2010 through March 2012, 373 consecutive patients underwent neurological surgery under guidance with 3T iMRI. A retrospective analysis was conducted regarding clinical efficiency. Results All surgery in the 373 patients was safe. The ratio of gross total resection for cerebral gliomas （n=161） was increased from 55.90% to 87.58%. The ratio of benefit in extent of resection was 39.13%. One hundred and fifty eight of the 161 glioma patients accomplished follow-up at 3 months postoperatively. Twenty of 161 patients （12.42%） suffered from early motor deficit after surgery. Late motor deficit was however observed in five of 158 patients （3.16%）. Twenty-one of 161 patients （13.04%） had early speech deficit and late speech deficit was only observed in six of 158 patients （3.80%）. The ratio of gross total resection for pituitary adenomas （n=49） was increased from 77.55% to 85.71%. The ratio of benefit in extent of resection was 10.2%. There were no iMRI-related adverse events even for patients who underwent awake craniotomy. Conclusion The 3T iMRI integrated neurosurgical suite provides high-quality intraoperative structural and functional imaging for real-time tumor resection control and accurate functional preservation, resulting in an improvement in maximal safe brain surgery.

Intraoperative high-field magnetic resonance imaging, multimodal neuronavigation, and intraoperative electrophysiological monitoring-guided surgery for treating supratentorial cavernomas

Objective: To determine the beneficial effects of intraoperative high-field magnetic resonance imaging (MRI), multimodal neuronavigation, and intraoperative electrophysiological monitoring-guided surgery for treating supratentorial cavernomas. Methods: Twelve patients with 13 supratentorial cavernomas were prospectively enrolled and operated while using a 1.5 T intraoperative MRI, multimodal neuronavigation, and intraoperative electrophysiological monitoring. All cavernomas were deeply located in subcortical areas or involved critical areas. Intraoperative high-field MRIs were obtained for the intraoperative“visu-alization”of surrounding eloquent structures,“brain shift”corrections, and navigational plan updates. Results: All cavernomas were successfully resected with guidance from intraoperative MRI, multimodal neuronavigation, and intraoperative electrophysiological monitoring. In 5 cases with supratentorial cavernomas, intraoperative “brain shift” severely deterred locating of the lesions;however, intraoperative MRI facilitated precise locating of these lesions. During long-term (>3 months) follow-up, some or all presenting signs and symptoms improved or resolved in 4 cases, but were unchanged in 7 patients. Conclusions: Intraoperative high-field MRI, multimodal neuronavigation, and intraoperative electrophysiological monitoring are helpful in surgeries for the treatment of small deeply seated subcortical cavernomas.

Identification of risk factors for poor language outcome in surgical resection of glioma involving the arcuate fasciculus:an observational study

The arcuate fasciculus is a critical component of the neural substrate of human language function.Surgical resection of glioma adjacent to the arcuate fasciculus likely damages this region.In this study,we evaluated the outcome of surgical resection of glioma adjacent to the arcuate fasciculus under the guidance of magnetic resonance imaging and diffusion tensor imaging,and we aimed to identify the risk factors for postoperative linguistic deficit.In total,54 patients with primary glioma adjacent to the arcuate fasciculus were included in this observational study.These patients comprised 38 men and 16 women(aged 43±11 years).All patients underwent surgical resenction of glioma under the guidance of magnetic resonance imaging and diffusion tensor imaging.Intraoperative images were updated when necessary for further resection.The gross total resection rate of the 54 patients increased from 38.9%to 70.4%by intraoperative magnetic resonance imaging.Preoperative language function and glioma-to-arcuate fasciculus distance were associated with poor language outcome.Multivariable logistic regression analyses showed that glioma-to-arcuate fasciculus distance was the major independent risk factor for poor outcome.The cutoff point of glioma-to-arcuate fasciculus distance for poor outcome was 3.2 mm.These findings suggest that intraoperative magnetic resonance imaging combined with diffusion tensor imaging of the arcuate fasciculus can help optimize tumor resection and result in the least damage to the arcuate fasciculus.Notably,glioma-to-arcuate fasciculus distance is a key independent risk factor for poor postoperative language outcome.This study was approved by the Ethics Committee of the Chinese PLA General Hospital,China(approval No.S2014-096-01)on October 11,2014.

Mechanism of Dynamic Near-infrared Fluorescence Cholangiography of Extrahepatic Bile Ducts and Applications in Detecting Bile Duct Injuries Using Indocyanine Green in Animal Models

Fluorescence intraoperative cholangiography（IOC） is a potential alternative for identifying anatomical variation and preventing iatrogenic bile duct injuries by using the near-infrared probe indocyanine green（ICG）. However, the dynamic process and mechanism of fluorescence IOC have not been elucidated in previous publications. Herein, the optical properties of the complex of ICG and bile, dynamic fluorescence cholangiography and iatrogenic bile duct injuries were investigated. The emission spectrum of ICG in bile peaked at 844 nm and ICG had higher tissue penetration. Extrahepatic bile ducts could fluoresce 2 min after intravenous injection, and the fluorescence intensity reached a peak at 8 min. In addition, biliary dynamics were observed owing to ICG excretion from the bile ducts into the duodenum. Quantitative analysis indicated that ICG-guided fluorescence IOC possessed a high signal to noise ratio compared to the surrounding peripheral tissue and the portal vein. Fluorescence IOC was based on rapid uptake of circulating ICG in plasma by hepatic cells, excretion of ICG into the bile and then its interaction with protein molecules in the bile. Moreover, fluorescence IOC was sensitive to detect bile duct ligation and acute bile duct perforation using ICG in rat models. All of the results indicated that fluorescence IOC using ICG is a valid alternative for the cholangiography of extrahepatic bile ducts and has potential for measurement of biliary dynamics.

Quality Evaluation of Image Recording Strategies for Limited Angle Tomography

In this paper we propose a new method for evaluating image recording strategies for limited angle tomography. In limited angle tomography exact three-dimensional （3-D） reconstruction is not achievable. With this method a metric for the reachable reconstruction quality by defined X-ray source trajectories is calculated. The result of our method is independent of reconstruction algorithms. Our approach is based on the gradients of the scanned volume and their grade of determinability. Compared to simulated reconstruction accuracy with simultaneous algebraic reconstruction techniques, the method of evaluation shows the same dependencies on X-ray source trajectories. By using the proposed method different source trajectories for a limited angle range are comparable with respect to the reachable reconstruction quality.