Correlation of cytology with subsequent histology.

<p>Correlation of cytology with subsequent histology.</p

Top six wavenumbers responsible for separating negative cytology from HPV, ASCUS and Cancer.

<p>Top six wavenumbers responsible for separating negative cytology from HPV, ASCUS and Cancer.</p

Analysis of infrared (IR) spectra from cervical cytology samples with subsequent histology (<i>n</i> = 154). LD1 and LD2 were used to plot the confidence ellipses for cancer (violet), high-grade lesion (red), low-grade lesion (blue) and Negative (green).

<p>(<b>A</b>) Comparison of linear discriminant analysis (LDA) scores plots of IR spectra according to conventional cytology grades: Negative <i>vs.</i> LSIL <i>vs.</i> HSIL; (<b>B</b>) Comparison of LDA scores plots according to subsequent histology grades: Normal <i>vs.</i> CIN1 <i>vs.</i> CIN2+ <i>vs.</i> Cancer. In the next two figures, the scores plot for discordant cytology and histology were depicted by double-coloured symbols, with the outer colour determining the cytology grade and the inner colour determining the histology grade; (<b>C</b>) Comparison of LDA scores plots derived from IR spectra analysed using cytology-based categories; and, (<b>D</b>) Comparison of LDA scores plots derived from IR spectra analysed using subsequent histology-based categories.</p

Infrared (IR) spectral points of cytology in relation to high-grade histology.

<p>(<b>A</b>) IR spectra for high-grade histology (CIN2+ and cancer) classified according to the screening cytology result and in relation to the confidence ellipses of histology grades; and, (<b>B</b>) Analysis of IR spectra of high-grade lesions cytology classified according to subsequent histology.</p

Comparison of infrared (IR) spectra from LBC samples using LDA scores plot with confidence ellipse representing confidence interval at 90% for the observed values.

<p>(<b>A</b>) Negative <i>vs.</i> LSIL <i>vs.</i> HSIL; (<b>B</b>) Negative vs. HSIL; (<b>C</b>) LSIL <i>vs.</i> HSIL; and, (<b>D</b>) Negative <i>vs.</i> LSIL; (<b>E</b>) Corresponding peak detection plot with top six wavenumbers responsible for segregation of Negative from LSIL and HSIL.</p

Infrared (IR) spectral points of cytology in relation to normal histology.

<p>(<b>A</b>) IR spectra for normal histology classified according to the screening cytology results and in relation to the confidence ellipses of histology grades; and, (<b>B</b>) Analysis of IR spectra from normal cytology classified according to subsequent histology.</p

Spectral variations amongst histology of HSIL cytology.

<p>Spectral variations amongst histology of HSIL cytology.</p

Flow diagram of sample collection, sample preparation, spectroscopy, pre-processing of spectra and feature extraction.

<p>After sampling of the transformation zone (TZ), the cells are suspended in ThinPrep solution. An aliquot of 6 ml of cytology specimen was centrifuged at 1,500 rpm for 5 min, after which the supernatant was then aspirated. The remaining cell pellet was re-suspended in 3 ml autoclaved distilled H₂O and centrifuged at 1500 rpm for 5 min, and the supernatant was again removed. This wash step was repeated three times and, the resulting cell pellet was then re-suspended in 0.5 ml autoclaved distilled H₂O and transferred to a low-E glass microscope slide. Slides were allowed to air-dry and stored in a desiccator until analysis. Infrared (IR) spectra were obtained using a Bruker TENSOR 27 FTIR spectrometer with Helios ATR attachment containing a diamond crystal. Using a CCTV camera, spectra were acquired from 10 independent sample locations. The datasets were processed using MATLAB R2010a software (Mathworks Inc, Natick, MA, USA) with the IRootLab toolbox (<a href="http://irootlab.googlecode.com" target="_blank">http://irootlab.googlecode.com</a>). IR spectra were pre-processed in three steps, which include cutting, baseline correction and normalization. Feature extraction was carried out using linear discriminant analysis, which allowed for segregation of classes and peak detection plots allowed identification of biomarkers.</p

Comparing various cytology grade spectra using multivariate analysis.

<p>(<b>A</b>) Comparison of spectral points for Negative <i>vs.</i> LSIL <i>vs.</i> HSIL (closed symbols) with HPV <i>vs.</i> ASCUS <i>vs.</i> Cancer (open symbols). Scores plots with confidence ellipse showing the relationship of (<b>B</b>) cancer with HSIL; (<b>C</b>) ASCUS with LSIL; and, (<b>D</b>) HPV-like features with Negative cytology; (<b>E</b>) Peak detection plot following linear discriminant analysis (LDA) showing top six wavenumbers responsible for segregation of Negative cytology from ASCUS, HPV and Cancer cytology.</p

Spectral variations amongst histology of Negative cytology.

<p>Spectral variations amongst histology of Negative cytology.</p