Oxygenated hemoglobin diffuse reflectance ratio for in vivo detection of oral pre-cancer

Abstract

Diffuse reflectance (DR) spectroscopy is a simple, low-cost, and noninvasive modality with potential for distinguishing oral precancer. Recently, in an ex vivo study, the DR spectral ratio (R545/R575) of oxygenated hemoglobin bands at 545 and 575 nm was used for grading malignancy. This work presents the results of clinical trials conducted in 29 patients to detect oral precancer using this ratio. We use site-specific normal spectra from a group of 36 healthy volunteers for comparison with those of patients. Toward this, in vivo DR spectra from 14 anatomical sites of the oral cavity of healthy volunteers are recorded on a miniature fiber optic spectrometer with white light excitation. The R545/R575 ratio is lowest for healthy tissues and appears to increase with the grade of malignancy. As compared to scatter plots that use the mean DR ratio from all anatomical sites, those using site-specific data show improved sensitivity and specificity for early diagnosis and grading of oral cancer. In the case of buccal mucosa, using scatter plots of R545/R575 ratio, we obtain a sensitivity of 100% and specificity of 86% for discriminating precancer (dysplasia) from hyperplasia, and a sensitivity of 97% and specificity of 86% for discriminating hyperplasia from normal.

Comparative evaluation of the diagnostic performance of autofluorescence and diffuse reflectance in oral cancer detection: a clinical study

“…This could be due to a reduction in production of oxygenated hemoglobin in the diseased regions. It has been reported that heme production via Heme cycle weakens in cancer cells due to a reduction in ferrochelatase activity [10,19]. The diagnostic accuracies obtained for the AF and DR techniques (Table 2) based on the comparison of the scatterplots of discriminant function scores ( Figures 5 and 6) with the pathological reports show the efficacy of these techniques in a clinical environment.…”

“…Zhu and Palmer [9] obtained a sensitivity and specificity of 80% for discriminating malignant and nonmalignant breast tissues using the Monte Carlo inverse model with a PCA algorithm. The DR spectral ratio (R545/R575) was used by Mallia et al [10] in a clinical trial to discriminate precancerous dysplastic lesions from hyperplastic tissue with a sensitivity of 100% and a specificity of 86%. Ramanujam et al [11] combined principal component analysis (PCA) and logistic regression for classification of human cervical tissue fluorescence in vivo and reported an overall sensitivity of 88% and specificity of 70% to differentiate squamous intraepithelial lesions (SILs) from normal squamous epithelia and inflammation.…”

Diffuse reflectance spectroscopy: diagnostic accuracy of a non-invasive screening technique for early detection of malignant changes in the oral cavity

“…Mallia et al 10 extended this technique for in vivo diagnosing and grading buccal cavity lesions in a clinical trial on 29 patients and 36 healthy volunteers with the help of a spectral ratio reference standard. In a recent study, Mallia et al 11 examined the potential of DRS as an alternative to autofluorescence spectroscopy in tongue-cancer detection.…”

Non-Invasive Techniques for Detection and Diagnosis of Oral Potentially Malignant Disorders

“…A current DRS system typically consists of an imaging device for recording diffuse reflectance images and a fiber-optic probe for relaying light to and from the instrument . Some studies have showed that information about tissue transformation, obtained in vivo with the aid of the oxygenated hemoglobin spectral ratio (R545/R575) algorithm, was able to differentiate normal mucosa, hyperplasia, dysplasia, and OSCC with high sensitivity and specificity (Table 1) (Mallia et al 2008(Mallia et al , 2010Jayanthi et al 2011). Moreover, Stephen et al (2013) suggested that DRS could be very effective as a screening tool for the location of oral PMDs.…”