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BACKGROUND AND OBJECTIVES In head and neck surgery, intraoperative and postoperative evaluation of tumor margins is achieved by histopathological assessment, which is a multistep process. Intraoperative analysis of tumor margins to obtain a preliminary diagnosis is usually carried out on frozen sections. Analysis of frozen sections is challenging due to technical difficulties in processing. Full-field optical coherence tomography (FFOCT) provides ex vivo images of fresh tissue samples at a microscopic scale without tissue processing. The objectives of our study were to define the diagnostic criteria required to interpret head and neck FFOCT images and to evaluate the reliability of a histological diagnosis made on an "optical biopsy" produced by head and neck FFOCT imaging compared with conventional histology. STUDY DESIGN/MATERIALS AND METHODS First, we established an atlas of comparative images (FFOCT/standard histology) and defined the diagnostic criteria based on FFOCT images. Two pathologists subsequently performed a blinded review on 57 FFOCT images (32 patients). Specificity and sensitivity were measured by comparison with the standard histological diagnosis. The primary endpoint was major concordance, defined as two classifications leading to the same therapeutic decision (treatment/no treatment). RESULTS Pathologists identified four main criteria for tissue diagnosis on FFOCT images: heterogeneous cell distribution, stromal reaction, coiling, and keratinization abnormalities. The correlation study showed good results, with sensitivity from 88% to 90% and specificity from 81% to 87%, regardless of whether the FFOCT image review was performed by a pathologist with or without previous experience in optical imaging. CONCLUSIONS Our results demonstrate that FFOCT images can be used by pathologists for differential diagnosis, and that high-resolution FFOCT imaging can provide an assessment of microscopic architecture in head and neck tissues without tissue processing requirements. Lasers Surg. Med. © 2020 Wiley Periodicals, Inc.

Probe-based confocal laser endomicroscopy (pCLE) is a noninvasive and real-time imaging technique allowing acquisition of in situ images of the tissue microarchitecture during oral surgery. We aimed to assess the diagnostic performance of pCLE combined with patent blue V (PB) in improving the management of early oral cavity, oro/hypopharyngeal, and laryngeal cancer by imaging squamous cell carcinoma in vivo. The prospective study enrolled 44 patients with early head and neck lesions. All patients underwent white-light inspection or panendoscopy depending on the lesion’s location, followed by pCLE imaging of the tumor core and its margins after topical application of PB. Each zone imaged by pCLE was interpreted at distance of the exam by three pathologists blinded to final histology. Most imaged zones could be presented to pathologists; the final sensitivity and specificity of pCLE imaging in head and neck cancers was 73.2–75% and 30–57.4%, respectively. During imaging, head and neck surgeons encountered some challenges that required resolving, such as accessing lesions with the flexible optical probe, achieving sufficiently precise imaging on the targeted tissues, and heterogeneous tissue staining by fluorescent dye. Final sensitivity scores were reasonable but final specificity scores were low. pCLE zones used to calculate specificity were acquired in areas of tumor margins, and the poor quality of the images acquired in these areas explains the final low specificity scores. Practical adjustments and technical training are needed to analyze head and neck lesions in various anatomical sites in real-time by pCLE.

New optical technologies enhancing localization or assessing viability of parathyroid glands (PG) during endocrine surgery have been reported in clinical studies. These technologies could become complementary to the surgeon's eyes and may improve surgical outcomes in thyroidectomy and parathyroidectomy. Here, we conducted a systematic review focusing on PG identification and functional assessment using optical methods to enhance surgery. A systematic literature review was performed using MEDLINE and Embase database. Two authors selected studies and extracted data; qualitative analysis was performed to summarize the characteristics of reported optical tools for thyroidectomy or parathyroidectomy. Identification and vascularisation of PG during surgery were evaluated. Clinical and biochemical outcomes were appraised when reported. Studies relating to parathyroidectomy or thyroidectomy combined with autofluorescence, fluorescent methylene blue, 5-aminolevulinic acid, indocyanine green (ICG), optical coherence tomography, laser speckle contrast imaging, dynamic optical contrast imaging and Raman spectroscopy were identified with MEDLINE and Embase. We included a total of 47 relevant articles with a total of 1615 patients enrolled. Each optical technique is described and appreciated related to its surgical purpose. Autofluorescence and ICG imaging of PG are the most widely reported optical technologies for identification and assessment of vascularisation of PG. Results are mainly based on observational studies and argue for the feasibility of both techniques in endocrine surgery but prospective randomized studies have not been performed. In vivo applications are still limited for the other methods and further investigations correlating these techniques with post-operative parathormone measurements are still needed before considering these technologies in clinical practice.

Parathyroid glands (PGs) can be particularly hard to distinguish from surrounding tissue and thus can be damaged or removed during thyroidectomy. Postoperative hypoparathyroidism is the most common complication after thyroidectomy. Very recently, it has been found that the parathyroid tissue shows near-infrared (NIR) auto-fluorescence which could be used for intraoperative detection, without any use of contrast agents. The work described here presents a histological validation ex vivo of the NIR imaging procedure and evaluates intraoperative PG detection by NIR auto-fluorescence using for the first time to our knowledge a commercially available clinical NIR imaging device. Ex vivo study on resected operative specimens combined with a prospective in vivo study of consecutive patients who underwent total or partial thyroid, or parathyroid surgery at a comprehensive cancer center. During surgery, any tissue suspected to be a potential PG by the surgeon was imaged with the Fluobeam 800 ® system. NIR imaging was compared to conventional histology (ex vivo) and/or visual identification by the surgeon (in vivo). We have validated NIR auto-fluorescence with an ex vivo study including 28 specimens. Sensitivity and specificity were 94.1 and 80 %, respectively. Intraoperative NIR imaging was performed in 35 patients and 81 parathyroids were identified. In 80/81 cases, the fluorescence signal was subjectively obvious on real-time visualization. We determined that PG fluorescence is 2.93 ± 1.59 times greater than thyroid fluorescence in vivo. Real-time NIR imaging based on parathyroid auto-fluorescence is fast, safe, and non-invasive and shows very encouraging results, for intraoperative parathyroid identification.

The purpose of this work was to assess the diagnostic value of magnetic resonance elastography (MRE) in addition to MRI to differentiate malignant from benign breast tumors, and the feasibility of performing MRE on the whole breast. MRE quantified biomechanical properties within the entire breast (50 slices) using an 11 min acquisition protocol at an isotropic image acquisition resolution of 2 × 2 × 2 mm3 . Fifty patients were included. Finally, 43 patients (median age 52) with a suspect breast lesion detected by mammography and/or ultrasound were examined by MRI and MRE at 1.5 T. The viscoelastic parameters, i.e. elasticity (Gd ), viscosity (Gl ), the magnitude of the complex shear modulus Gd2+Gl2, and the phase angle y=2πatanGlGd, were measured via MRE and correlated with MRI Breast Imaging-Reporting and Data System (BI-RADS) score, histological type, and histological grade. Stroma component and angiogenesis were also correlated with viscoelastic properties. In the 43 lesions, Gd decreased and y increased with the MRI BI-RADS score (pGd = 0.02, py = 0.002), whereas (Gl ) and y were increased in malignant lesions (pGl = 0.045, py = 0.0004). The area under the curve increased from 0.84 for MRI BI-RADS alone to 0.92 with the MRI BI-RADS and y (AUC increase +0.08; 95% CI (-0.003; 0.16)). Lesion characterization using the y parameter increased the diagnostic accuracy. The phase angle y was found to have a significant role (p = 0.01) in predicting malignancy independently of the MRI BI-RADS. Interestingly, histological analysis showed no correlation between viscoelastic parameters and percentage and type of stroma, CD34 quantification of vessels, or histological grade. The combination of MRE and MRI improves the diagnostic accuracy for breast lesions in the studied cohort. In particular, the phase angle y was found to have a significant role in predicting malignancy in addition to BI-RADS.