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    ABSTRACT: To evaluate the performance of 3-dimensional (3D) virtual neck exploration (VNE) as a modality for preoperative localization of parathyroid adenomas in primary hyperparathyroidism and assess the feasibility of using augmented reality to guide parathyroidectomy as a step toward minimally invasive imageguided surgery. Enhanced 3D rendering methods can be used to transform computed tomographic scan images into a model for 3D VNE. In addition to a standard imaging modality, 3D VNE was performed in all patients and used to preoperatively plan minimally invasive parathyroidectomy. All preoperative localization studies were analyzed for their sensitivity, specificity, positive predictive value, and negative predictive value for the correct side of the adenoma(s) (lateralization) and the correct quadrant of the neck (localization). The 3D VNE model was used to generate intraoperative augmented reality in 3 cases. Tertiary care center. A total of 114 consecutive patients with primary hyperparathyroidism were included from January 8, 2008, through July 26, 2011. The accuracy of 3D VNE in lateralization and localization was 77.2% and 64.9%, respectively. Virtual neck exploration had superior sensitivity to ultrasonography (P.001), sestamibi scanning (P=.07), and standard computed tomography (P.001). Use of the 3D model for intraoperative augmented reality was feasible. 3-Dimensional VNE is an excellent tool in preoperative localization of parathyroid adenomas with sensitivity, specificity, and diagnostic accuracy commensurate with accepted first-line imaging modalities. The added value of 3D VNE includes enhanced preoperative planning and intraoperative augmented reality to enable less-invasive image-guided surgery.
    JAMA SURGERY 03/2013; 148(3):232-8; discussion 238. DOI:10.1001/jamasurg.2013.739 · 3.94 Impact Factor
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    ABSTRACT: Objective: Our aim was to evaluate a fluorescence-based enhanced-reality system to assess intestinal viability in a laparoscopic mesenteric ischemia model. Materials and methods: A small bowel loop was exposed, and 3 to 4 mesenteric vessels were clipped in 6 pigs. Indocyanine green (ICG) was administered intravenously 15 minutes later. The bowel was illuminated with an incoherent light source laparoscope (D-light-P, KarlStorz). The ICG fluorescence signal was analyzed with Ad Hoc imaging software (VR-RENDER), which provides a digital perfusion cartography that was superimposed to the intraoperative laparoscopic image [augmented reality (AR) synthesis]. Five regions of interest (ROIs) were marked under AR guidance (1, 2a-2b, 3a-3b corresponding to the ischemic, marginal, and vascularized zones, respectively). One hour later, capillary blood samples were obtained by puncturing the bowel serosa at the identified ROIs and lactates were measured using the EDGE analyzer. A surgical biopsy of each intestinal ROI was sent for mitochondrial respiratory rate assessment and for metabolites quantification. Results: Mean capillary lactate levels were 3.98 (SD = 1.91) versus 1.05 (SD = 0.46) versus 0.74 (SD = 0.34) mmol/L at ROI 1 versus 2a-2b (P = 0.0001) versus 3a-3b (P = 0.0001), respectively. Mean maximal mitochondrial respiratory rate was 104.4 (±21.58) pmolO2/second/mg at the ROI 1 versus 191.1 ± 14.48 (2b, P = 0.03) versus 180.4 ± 16.71 (3a, P = 0.02) versus 199.2 ± 25.21 (3b, P = 0.02). Alanine, choline, ethanolamine, glucose, lactate, myoinositol, phosphocholine, sylloinositol, and valine showed statistically significant different concentrations between ischemic and nonischemic segments. Conclusions: Fluorescence-based AR may effectively detect the boundary between the ischemic and the vascularized zones in this experimental model.
    Annals of surgery 03/2013; DOI:10.1097/SLA.0b013e31828d4ab3 · 8.33 Impact Factor
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    ABSTRACT: Background: The aim of this study was to assess the accuracy of a novel imaging modality, three-dimensional (3D) metabolic and radiologic gathered evaluation (MeRGE), for localizing parathyroid adenomas (PAs). Methods: Consecutive patients presenting with primary hyperparathyroidism who underwent both thin-slice cervical computed tomography (CT) and (99m)Tc-sestamibi (MIBI) scanning were included. 3D-CT reconstruction was obtained using VR-RENDER, which was used to perform 3D virtual neck exploration (3D-VNE). The MIBI scan was then fused with the 3D reconstruction to obtain 3D-MeRGE. Sensitivity, specificity, and accuracy were assessed. Parathyroid gland volume and preoperative parathormone (PTH) levels were analyzed as predictive factors of correct localization (i.e., correct quadrant). Results: A total of 108 cervical quadrants (27 patients) were analyzed. Sensitivities were 79.31, 75.86, 65.51, and 58.61 % with 3D-MeRGE, 3D-VNE, MIBI, and CT, respectively. Specificity was highest with CT (94.93 %) followed by 3D-VNE (92.4 %). MIBI and 3D-MeRGE had the same specificity (88.6 %). 3D-MeRGE and 3D-VNE achieved higher accuracy than MIBI or CT alone. Mean PTH values were significantly higher in patients with lesions that were correctly identified (true positive, TP) than in those whose lesions were missed (false negative, FN) with 3D-VNE (219.60 ± 212.77 vs. 98.75 ± 12.76 pg/ml; p = 0.01) and 3D-MeRGE (217.69 ± 213.76 vs. 09.75 ± 20.48 pg/ml; p = 0.02). The mean parathyroid gland volume difference between TP and FN was statistically significant with all modalities except CT. Conclusions: 3D-MeRGE and 3D-VNE showed high accuracy for localization of PAs. 3D-MeRGE performed better than MIBI or CT alone for detecting small adenomas and those with a low PTH level.
    World Journal of Surgery 04/2013; DOI:10.1007/s00268-013-2021-x · 2.64 Impact Factor
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