Modern Trends in Hyperspectral Image Analysis: A Review <s> B. MEDICAL DIAGNOSIS <s> We compared the diagnostic capabilities of MRI to CT, evoked potentials (EP), and CSF oligoclonal banding analysis in a prospective evaluation of 200 patients with suspected multiple sclerosis (MS). MRI was the best method for demonstrating dissemination in space. An abnormal appropriate EP in monosymptomatic disease was usually supported by MRI and CSF anaylsis as being predictive of MS as a clinical diagnosis. A normal appropriate EP study was not satisfactory because MRI and CSF analysis often did not support a diagnosis of non-MS . When there is agreement between three of these paraclinical studies, the diagnosis of MS is probably unequivocal. For use in research studies, laboratory-supported definite MS (LSDMS) could be diagnosed in 85 patients of the total 200 (42.5%), in 19/38 (50%) of optic neuritis (ON) patients, and in 24/52 (46%) of chronic progressive myelopathy (CPM) patients. MRI was 100% successful in identifying patients who qualified for LSDMS in the ON and CPM groups. In a short follow-up (less than 1 year), 19/200 (10%) went on to develop clinically definite MS (CDMS), and MRI predicted that diagnosis in 18/19 (95%). Only long-term follow-up will show how well these studies and the category of LSDMS predict the development of CDMS. The clinical diagnosis of MS (CDMS), even though only 95% accurate, must remain the gold standard. <s> BIB001 </s> Modern Trends in Hyperspectral Image Analysis: A Review <s> B. MEDICAL DIAGNOSIS <s> We investigated the use of high resolution hyperspectral imaging microscopy to detect abnormalities in skin tissue using hematoxylin eosin stained preparations of normal and abnormal skin, benign nevi and melanomas. A goal of this study was to provide objective data that could be utilized by any researcher; and form the beginnings of a reference spectral data base. All spectral characterizations were acquired in percent transmission, and absorption, with contiguous wavelength acquisition between 400 and 800 nm; and a spectral resolution of approximately 1 nm. Biopsy sections were characterized with varying sample thickness, staining and magnification in order to determine their impact on spectral characterizations. Spectra were classified using spectral waveform cross correlation analysis, an algorithm that is linearity invariant. Classified spectra were incorporated into spectral libraries; and all spectra acquired from the field of view were correlated with library spectra to a quantified, user determined, confidence threshold (minimum correlation coefficient). The results revealed that all skin conditions in our initial data sets could be objectively differentiated providing that staining and section thickness was controlled. We also demonstrated that it is likely that a reference spectral library database could be created to include bioinformatics and cluster analysis. This would assist multiple laboratories to participate in the input and retrieval of target spectral information. <s> BIB002 </s> Modern Trends in Hyperspectral Image Analysis: A Review <s> B. MEDICAL DIAGNOSIS <s> AIM ::: To compare the diagnostic accuracy of computed tomography (CT) and magnetic resonance imaging (MRI) in the diagnosis of lymph node metastases in prostate cancer. ::: ::: ::: METHODS ::: After a comprehensive literature search, studies were included that allowed construction of contingency tables for detection of lymph node metastases using CT or MRI. In addition, a summary receiver-operating characteristic (ROC) analysis was performed. ::: ::: ::: RESULTS ::: A total of 24 studies were included. For CT, pooled sensitivity was 0.42 (0.26-0.56 95% CI) and pooled specificity was 0.82 (0.8-0.83 95% CI). For MRI, the pooled sensitivity was 0.39 (0.22-0.56 95% CI) and pooled specificity was 0.82 (0.79-0.83 95% CI). The differences in performance of CT and MRI were not statistically significant. ::: ::: ::: CONCLUSION ::: CT and MRI demonstrate an equally poor performance in the detection of lymph node metastases from prostate cancer. Reliance on either CT or MRI will misrepresent the patient's true status regarding nodal metastases, and thus misdirect the therapeutic strategies offered to the patient. <s> BIB003 </s> Modern Trends in Hyperspectral Image Analysis: A Review <s> B. MEDICAL DIAGNOSIS <s> A hyperspectral imaging system to measure and analyze the reflectance spectra of the human tongue with high spatial resolution is proposed for tongue tumor detection. To achieve fast and accurate performance for detecting tongue tumors, reflectance data were collected using spectral acousto-optic tunable filters and a spectral adapter, and sparse representation was used for the data analysis algorithm. Based on the tumor image database, a recognition rate of 96.5% was achieved. The experimental results show that hyperspectral imaging for tongue tumor diagnosis, together with the spectroscopic classification method provide a new approach for the noninvasive computer-aided diagnosis of tongue tumors. <s> BIB004 </s> Modern Trends in Hyperspectral Image Analysis: A Review <s> B. MEDICAL DIAGNOSIS <s> We encapsulate indocyanine green (ICG) in poly[(D,L-lactide-co-glycolide)-co-PEG] diblock (PLGA-PEG) microballoons for real-time fluorescence and hyperspectral imaging of biliary anatomy. ICG-loaded microballoons show superior fluorescence characteristics and slower degradation in comparison with pure ICG. The use of ICG-loaded microballoons in biliary imaging is demonstrated in both biliary-simulating phantoms and an ex vivo tissue model. The biliary-simulating phantoms are prepared by embedding ICG-loaded microballoons in agar gel and imaged by a fluorescence imaging module in a Da Vinci surgical robot. The ex vivo model consists of liver, gallbladder, common bile duct, and part of the duodenum freshly dissected from a domestic swine. After ICG-loaded microballoons are injected into the gallbladder, the biliary structure is imaged by both hyperspectral and fluorescence imaging modalities. Advanced spectral analysis and image processing algorithms are developed to classify the tissue types and identify the biliary anatomy. While fluorescence imaging provides dynamic information of movement and flow in the surgical region of interest, data from hyperspectral imaging allow for rapid identification of the bile duct and safe exclusion of any contaminant fluorescence from tissue not part of the biliary anatomy. Our experiments demonstrate the technical feasibility of using ICG-loaded microballoons for biliary imaging in cholecystectomy. <s> BIB005 </s> Modern Trends in Hyperspectral Image Analysis: A Review <s> B. MEDICAL DIAGNOSIS <s> Fourier transform infrared (FTIR) imaging was applied on histopathological specimens of breast cancer of different tumor histological grades. Focus was given to the extracellular matrix. FTIR spectral changes were observed when examining the extracellular matrix close to and far from carcinoma. Major changes were observed, in particular in the relative intensities of the collagen bands at 1640 and 1630 cm−1. PCA analysis and global fitting indicate a continuous progression in collagen spectral features when moving away from the tumor. These preliminary results suggest FTIR spectral features present in the 1700–1600 cm−1 spectral range could be used as spectral markers to identify cancer-induced modifications in collagen. This chemical imaging approach to analyze the breast cancer microenvironment could be used in the future for improving diagnostics of breast cancer. <s> BIB006 </s> Modern Trends in Hyperspectral Image Analysis: A Review <s> B. MEDICAL DIAGNOSIS <s> UNLABELLED ::: Abstract Background and Purpose: Digital light processing-based hyperspectral imaging (DLP(®)-HSI) was adapted for use during laparoscopic surgery by coupling the spectral illumination source with a conventional laparoscopic light guide and incorporating a customized digital charge-coupled device camera for image acquisition. The system was used to characterize renal oxygenation during robot-assisted laparoscopic partial nephrectomy (RALPN) in humans. ::: ::: ::: PATIENTS AND METHODS ::: After Institutional Review Board approval, laparoscopic DLP-HSI was performed in consecutive patients undergoing RALPN at our institution. Time trends in relative tissue oxygen saturation (%HbO2) were descriptively analyzed. Associations between %HbO2 and patient age, comorbidities, and estimated glomerular filtration rate (eGFR) were investigated using the Kendall tau test. ::: ::: ::: RESULTS ::: Laparoscopic DLP-HSI was performed in 18 patients between May 2011 and February 2012. Median (interquartile range; IQR) age was 55.9 (49-67.5) years. Of the patients, 10/18 (56%) were men and 12/18 (66.7%) had a history of hypertension, diabetes, and/or tobacco use. Median (IQR) %HbO2 before, during, and after ischemia was 60.8% (57.9-68.2%), 53.6% (46.8-55.1%), and 61.5% (54.9-67.6%), respectively. Baseline %HbO2 was inversely associated with preoperative eGFR (τ=-0.38; P=0.036), and eGFR at most recent follow-up (τ=-0.38; P=0.036). Baseline or ischemic %HbO2 did not correlate with hypertension, diabetes, and/or tobacco history. Younger patients (<56 years) had a lower median baseline %HbO2 (P=0.07) and a higher median preoperative eGFR (P=0.038), than their older counterparts. ::: ::: ::: CONCLUSION ::: The laparoscopic HSI system successfully characterized dynamic changes in renal oxygenation during RALPN. Intraoperative laparoscopic HSI outcomes have the potential to predict postoperative individual kidney function. <s> BIB007
Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) have been traditionally used for clinical analysis. Paty et al. BIB001 compared the potential of MRI and CT for detection of multiple sclerosis (MS) during the evaluation of over 200 patients. Hovels et al. BIB003 used both CT and MRI diagnosis of lymph node metastases in prostate cancer. MRI yielded better results in clinical diagnosis. Over the past decades, modern spectral imaging techniques have proved their significance in medical imaging by providing added potential to medical experts at higher speed and accuracy. The optical characteristics of tissues provide valuable diagnostic information. Hyperspectral image analysis is being widely used for medical diagnosis due to its ability to provide real time images of biomarker information and spectral information of tissues. Besides diagnosis, HSI systems are also used in image guided surgery. Kumar et al. BIB006 proposed a PCA and Fourier Transform Infrared (FTIR) Spectroscopy based imaging system for diagnosis of breast cancer. FTIR was applied on histopathological specimens of breast cancer with various histological grades and spectral changes near carcinoma were reported. The data was analyzed using PCA. Prominent features were found in the 5882∼6250nm band which could be used for cancer identification. The reflectance spectra of tongue were noninvasively measured and analyzed by Liu et al. BIB004 for tumor detection. Dicker et al. BIB002 distinguished between malignant and benign dermal tissue in the spectral domain in the routine H&E stained samples. In their findings, the spectral signatures differences could be seen if the section thickness and staining time are controlled. A melanoma lesion and interstitial areas are shown in grayscale representation in Figure 4 . Mitra et al. BIB005 scanned the biliary structure using both fluorescence and reflectance imaging for classification of different tissues and identification of the biliary anatomy. Fluorescence imaging provided dynamic information about VOLUME 6, 2018 movement and flow in the surgical ROI whereas the hyperspectral image information helped in identification of the bileduct shown in Figure 5 . The hyperspectral information also allowed for safe exclusion of contaminant fluorescence in tissues which is not included in the biliary anatomy. In BIB005 , the biliary structure of tissues was scanned using fluorescence and reflectance imaging for identification of gall bladder diseases. Spectral analysis and image processing techniques were employed for identification of biliary anatomy and classification of tissues. Dynamic information of motion in the surgical region was provided by fluorescence imaging while hyperspectral imagery allowed for safe exclusion of contaminated fluorescence from tissues and provided valuable information for the identification of the bileduct. Campbell et al.  have proposed the use of Laparoscopic Partial Nephrectomy (LPN) for diagnosis of renal cortical tumors. Olweny et al. BIB007 used Digital Light Processing (DLP) based HSI for computer assisted LPN to characterize renal oxygenation. The clinical study was performed in eighteen patients. The proposed system was able to successfully characterize dynamic changes in renal oxygenation during LPN.