PROCESS FOR VISUAL DETERMINATION OF TISSUE BIOLOGY

Abstract

A method of analysing a target bodily tissue of a subject. The method involves manipulating image data from the target bodily tissue and a background bodily tissue after dosing the subject with a contrast agent. The relative intensities of the light emitted from selected areas of the target bodily tissue and background bodily tissue at different time points after dosing are compared to determine whether 1) the intensity of light emitted from the target bodily tissue is lower than the intensity of light emitted from the background bodily tissue during the first part of the time period; and/or 2) the intensity of light emitted from the target bodily tissue is higher than the intensity of light emitted from the background bodily tissue during the second part of the time period; to assist in the determination of whether the target bodily tissue is benign or malignant.

Claims

1. A method of analysing a target bodily tissue of a subject, the method comprising the steps of: a) receiving image data of the target bodily tissue and a background bodily tissue adjacent to the target bodily tissue, the image data being obtained over a time period after dosing the subject with a contrast agent; b) determining an intensity of light emitted from a first area of the target bodily tissue and an intensity of light emitted from a first area of the background bodily tissue at a plurality of time points during the time period, the intensity of light emitted from the target bodily tissue and the background bodily tissue at each of the plurality of time points being dependent upon the amount or brightness of contrast agent present in said tissues at each time point; c) comparing the intensity of light emitted from the first area of the target bodily tissue and the intensity of light emitted from the first area of the background bodily tissue over the plurality of time points; d) determining for a first part of the time period and a second part of the time period, the first part of the time period being earlier in the time period than the second part of the time period, whether: 1) the intensity of light emitted from the target bodily tissue is lower than the intensity of light emitted from the background bodily tissue during the first part of the time period; and/or 2) the intensity of light emitted from the target bodily tissue is higher than the intensity of light emitted from the background bodily tissue during the second part of the time period; wherein a negative determination in relation to 1) and/or 2) is indicative of the target bodily tissue being benign and a positive determination in relation to 1) and/or 2) is indicative of the target bodily tissue being malignant.

2. The method according to claim 1, wherein the target bodily tissue is a rectal lesion.

3. The method according to claim 1, wherein the image data was obtained whilst the target bodily tissue and the background bodily tissue were irradiated with near infrared light.

4. The method according to claim 1, wherein the time period is at least 5 minutes long.

5. The method according to claim 1, wherein the contrast agent is indocyanine green.

6. The method according to claim 1, wherein the image data is received in RGB format and step b) involves combining red, green and brown channel data for each pixel in the video recording in the first area of the target bodily tissue and in the first area of the background bodily tissue to provide a grayscale format comprising a single data point for each pixel.

7. The method according to claim 1, wherein the plurality of time points are separated by intervals of up to 120 seconds.

8. The method according to claim 1, wherein the first part of the time period starts at 0 minutes into the time period and ends at up to 2 minutes into the time period.

9. The method according to claim 1, wherein the second part of the time period starts at up to 25 minutes into the time period and ends at least 30 minutes into the time period.

10. The method according to claim 1, wherein step d) 2) involves determining whether the intensity of light emitted from the target bodily tissue and the intensity of light emitted from the background bodily tissue have a convergent or divergent relationship over the second part of the time period, wherein a convergent relationship is indicative of the target bodily tissue being benign and a divergent relationship is indicative of the target bodily tissue being malignant.

11. A device for analysing a target bodily tissue of a subject, the device comprising a visual inspection unit and a data analysis unit; wherein the visual inspection unit comprises a visible light source and an image data capture unit; and wherein the data analysis unit is adapted to: a) receive, from the image data capture unit, image data of said target bodily tissue and said background bodily tissue adjacent to said target bodily tissue, said image data taken over a time period; b) determine an intensity of light emitted from a first area of said target bodily tissue and an intensity of light emitted from a first area of said background bodily tissue at a plurality of time points of said time period; and c) compare said intensity of light emitted from said first area of said target bodily tissue and said intensity of light emitted from said first area of said background bodily tissue over said plurality of time points.

12. The device according to claim 11, wherein the data analysis unit is adapted to: d) determine whether: 1) said intensity of light emitted from said target bodily tissue is lower than said intensity of light emitted from said background bodily tissue during a first part of said time period; and/or 2) said intensity of light emitted from said target bodily tissue is higher than said intensity of light emitted from said background bodily tissue during said second part of said time period.

13. The device according to claim 11, wherein the visual inspection unit is an endoscope.

14. The device according to claim 11, wherein the visual inspection unit comprises a near infra-red light source.

15. A method of determining whether a target bodily tissue is benign or malignant, the method comprising the steps of: a) dosing the subject with a contrast agent; b) obtaining image data of the target bodily tissue and a background bodily tissue adjacent to the target bodily tissue, over a time period after dosing the subject with a contrast agent; c) determining an intensity of light emitted from a first area of the target bodily tissue and an intensity of light emitted from a first area of the background bodily tissue at a plurality of time points during the time period, the intensity of light emitted from the target bodily tissue and the background bodily tissue at each of the plurality of time points being dependent upon the amount of contrast agent present in said tissues at each time point; d) comparing the intensity of light emitted from the first area of the target bodily tissue and the intensity of light emitted from the first area of the background bodily tissue over the plurality of time points; e) determining for a first part of the time period and a second part of the time period, the first part of the time period being earlier in the time period than the second part of the time period, whether: 1) the intensity of light emitted from the target bodily tissue is lower than the intensity of light emitted from the background bodily tissue during the first part of the time period; and/or 2) the intensity of light emitted from the target bodily tissue is higher than the intensity of light emitted from the background bodily tissue during the second part of the time period; wherein a negative determination in relation to 1) and/or 2) is indicative of the target bodily tissue being benign and a positive determination in relation to 1) and/or 2) is indicative of the target bodily tissue being malignant; f) determining based on the outcome of step d) whether the target bodily tissue is benign or malignant.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0087] For a better understanding of the invention, and to show how example embodiments may be carried into effect, reference will now be made to the accompanying drawings in which:

[0088] FIG. 1 shows an example of the view of the image data received in step a) of the method of the first aspect.

[0089] FIGS. 2 and 3 show graphs comparing the surface to background ratios of light intensity from malignant and benign tumours.

[0090] FIG. 4 shows a graph of light intensity from a rectal polyp and background healthy tissue during an initial phase of the time period.

[0091] FIG. 5 shows a graph of light intensity from a rectal cancer and background healthy tissue during an initial phase of the time period.

[0092] FIG. 6 shows a graph of light intensity from a benign rectal polyp and background healthy tissue, over 25 min.

[0093] FIG. 7 shows a graph of light intensity from a rectal cancer and background healthy tissue.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

[0094] Method

[0095] 16 adult male and female patients with suspected rectal tumours were recruited onto a study involving the method and device of the present invention. The suspected rectal tumours had previously been diagnosed after endoscopy with or without biopsies. Patients with any history of allergic reaction to iodine were excluded.

[0096] The rectal lesions present in these patients were visualized transanally by using the pinpoint Novadaq laparoscope under NIR light. The method of visualisation varied depending on the location of the suspected tumour. For low rectal lesions, a lone star, a proctoscope or an Eisenhammer speculum was used for optimal visualisation. For high rectal lesions a rigid sigmoidoscope or TAMIS port was used.

[0097] Once the lesion was visualised and the setup was complete, 0.25 mg per kg body weight of patient of ICG contrast agent was injected intravenously and video (image data) recorded in the NIR mode. The video recording taken consisted of real colour, infrared and composite images. During the recording, the lesion (suspected tumour) target tissue and the background tissue adjacent to the lesion were both visible in the same frame for the purpose of analysis. The setup for the video recording was very important. It was necessary to ensure that stable clear views of both the lesion and the healthy background tissue were maintained throughout. Any fluid like mucus or blood gave a spurious reading so every attempt was made to keep the field of view dry. This was made possible with an ENT suction tube with a narrow diameter allowing insertion along the 10 mm Novadaq laparoscope through the rigid sigmoidoscope so as to get uninterrupted video data. Video was recorded for 25 to 30 minutes from the time of injection of ICG.

[0098] At the time of taking the video recording, note was made of the initial uptake of ICG by the lesion versus the background tissue and the washout of the florescence (and therefore the ICG) at 25 to 30 minutes to reach a provisional determination of the malignant or benign state of the target tissue. However, in around 50% of the cases these differences were very subtle so could not be determined by eye. Therefore the intensity of the light emitted by the tissue, and therefore recorded in the video recording, was measured using ImageJ and Mat Lab software. The data analysis comprised the following steps:

[0099] 1. Data Extraction

[0100] The video recording data (100, FIG. 1) consisted of a visible light image thumbnail (102), an infrared image thumbnail (103) and a false colour composite image thumbnail (104), with each image available to be shown in real time in the larger main display image (101). This data is captured during the procedure and the type of main display image can be selected based on the needs of the surgeon during the investigation, so the analysis was performed on the thumbnail images which remain available throughout the video dataset, irrespective of the type of main display image.

[0101] The captured video data was saved in MP4 (.mp4) format or as a number of datasets stitched together in QuickTime format (.mov). The framerate of the video recording was typically 29 frames/second. These images were analysed using the FIJI image processing software alongside MATLAB software for some pre-processing tasks.

[0102] In order to reduce the number of frames and expedite analysis in the FIJI software, MATLAB was used to extract one frame from each second of the video recording. This was done using the Video Reader and Video Writer functions of MATLAB. This resulted in 1500-2000 frames per analysis, which corresponds to about 25-30 minutes of video recording. The resultant selected video recording data was saved in an uncompressed AVI (.avi) format to allow for easy import into the FIJI software.

[0103] The original video recording data was displayed in an RGB format, which has three different colour channels corresponding to red (R), green (G) and blue (B). Each of these colour channels was segmented into 256 discrete levels (0-255) corresponding to shades of the channel colour. These shades are the various amounts of light which have fallen on the RGB pixels of the video recording equipment. The video recording data was then copied and converted to grayscale data to allow for intensity analysis of the infrared thumbnail image. For further ease of analysis the image was also cropped to the size of the thumbnail at this point.

[0104] In converting the video recording data to a grayscale format, the 256 discrete levels were preserved but converted to a weighted sum of the three channels (RGB) into another channel. This summed channel gives the total amount or intensity of light which has fallen on each pixel (and therefore corresponds to the light emitted from each specific area of the target and background tissues). The light levels, and hence the concentration of ICG, can then be represented by a single value of grayscale rather than by three values of the RGB colour.

[0105] FIJI software was used to open the original video recording data and the cropped grayscale data and synchronise the actions between these windows. A point measurement tool was then placed over a region of target tissue and a region of healthy background tissue in each frame, and the measurements of these areas recorded.

[0106] As the intensity image (the grayscale image) and the original image have been synchronised, this allowed the target tissue to be identified in the original image and the measurements of the intensity image to be taken from the same position as identified in the original image. The placements of all point measurements were made with the consensus of a medical physicist and a surgical doctor experienced in this field for the whole duration of the video.

[0107] The relative measurements obtained in this manner allowed the use of these measurements without the need for a calibration for contrast agent concentration, as it gave only the difference between the contrast agent concentration in the tumour and the healthy background, not the absolute measure. The use of a point measurement also allowed the analysis to be independent of variations in size of the target tissue.

[0108] 2. Data Analytics

[0109] The relative intensity data was exported from FIJI as a Comma Space Variable (.csv) file. This file can be imported into Microsoft Excel or equivalent. The data was plotted as a scatter chart with the image frame number on the x-axis (this corresponds to the time point the measurement was taken) and the pixel value on the y-axis (this corresponds to the intensity of the ICG, and therefore corresponds to its concentration). The pixel or intensity values can only be compared if they have been measured in the same frame.

[0110] The data was fitted with a logarithmic curve; this can be done using the trend fitting function which is available in Microsoft Excel. Logarithmic curves are used to smoothen variations or outliers in the data and to provide a pattern of intensity trace. Ratio data was obtained by comparing the intensity values from the same frame for both the target and the healthy tissue. Mean intensities and target tissue to background ratios were also compared both before resection and in ex vivo samples post resection.

[0111] A provisional determination of the malignant or benign state of the suspected rectal tumour tissue for all patients was made based on the video recording data analysis and compared with a histological analysis which was performed post resection.

[0112] The intensity data was then analysed to reach a provisional diagnosis which is compared to the histological diagnosis post resection.

[0113] Results

[0114] Single point in time variables like absolute or mean intensities and surface to background ratios (SBR) were explored for their discriminatory information. However, these single time values could not differentiate the benign lesions from cancers (see FIGS. 2 and 3).

[0115] The method described above, which may be described as a dynamic visual analysis (DVA) which involved determining the relationship between the dynamic intensity traces of lesion and healthy background tissue, showed consistency in differentiating the cancers from the benign lesions.

[0116] The following dynamic variables were used in the differentiation.

[0117] A. Initial Uptake

[0118] We observed that the initial uptake of the ICG contrast agent in benign lesions was either synchronous with the background tissue or was ahead of the background tissue. These observations were confirmed graphically by using the MATLAB and ImageJ (FIG. 4). FIG. 4 shows the intensity trace of a rectal polyp for 300 seconds (i.e. an initial phase or “first part” of the time period over which the video recording has been made). The time in seconds is plotted on the x-axis and the florescence (light) intensity on the y-axis. The polyp is actually more fluorescent than the normal background tissue from the beginning and there is no lag in the uptake of the ICG. In cancerous tissue, there was a definite lag in the initial uptake of the ICG. This observation was often difficult to appreciate by the human eye but was much clearer once graphically plotted (FIG. 5). FIG. 5 shows the intensity data of a rectal cancer over 200 seconds as compared to normal background tissue. The y-axis gives the light intensity while the x-axis is the time in seconds. The cancer lags in the uptake of ICG initially as evident by the intensity trace.

[0119] B. Washout of Contrast Agent

[0120] At 25 to 30 minutes most of the ICG tends to washout of benign lesions while cancerous tissue retains it for longer.

[0121] We noted some disparity between observers while commenting on the washout phase (i.e. a “second part” of the time period of the video recording) at 25-30 minutes whether the lesions were still florescent or not. Therefore the relative intensities had to be quantified. The whole intensity trace of the lesion and the background tissue were plotted together. After inserting the logarithmic trend lines to exclude the outliers, further discriminatory information was extracted. In benign lesions the trend lines were convergent over time, particularly during the “washout” period, and even crossed in some patients. FIG. 6 shows the intensity trace of a benign rectal polyp over 25 min. There is hardly any difference in the intensity between the polyp (line 602) and healthy tissue (line 601) at 25 minutes and the trend lines are convergent over time.

[0122] In cancerous tissue, the trend lines were actually divergent (see FIG. 7). FIG. 7 shows the complete intensity trace of a rectal cancer in comparison with the background healthy tissue showing the differential retention of the ICG at 25-30 minutes. The trend lines are divergent over time.

[0123] The provisional diagnosis after the DVA was based on at least 1 variable being confidently reported. One case was excluded as the video recording lacked the early uptake part and there were no data points recorded in the latter part of the video recording to confidently analyse and make a determination. In 2 cases the initial few seconds of the uptake was not recorded but the complete 25-30 minutes video was available for analysis and the diagnosis was based on the trend lines. Also in 2 patients only the initial uptake was confidently recorded so the diagnosis was based on whether there was a difference in early uptake.

[0124] Histological Comparison

[0125] Based on the dynamic video analysis discussed above, of the 15 patients, 8 lesions were determined as benign and then confirmed as benign by histology post resection. The other 7 lesions were determined as being cancerous, which was again confirmed by histology post resection.

[0126] In 3 of the patients, the dynamic video analysis was performed pre and post chemo radiotherapy (CRT). In one of the post CRT patients, only the initial uptake was confidently recorded so the diagnosis was based on this uptake data only. In all 3 of these patients, the post CRT analysis confirmed the target tissue was cancerous meaning these patients were not suitable for a “watch and wait” option and were sent for radical resection of the target tissue. Histology confirmed residual cancer in all 3 cases.

[0127] These results show that the real time optical determination of the malignant or benign state of a suspected target tissue is possible by the method of the present invention. Implementing this method into wider clinical practice may therefore save considerable cost, time and patient morbidity due to the ease, speed and accuracy of the method compared to current methods and by allowing a clinician to only treat suspected cancerous tissue when necessary.

[0128] In summary, the present invention provides a method of analysing a target bodily tissue of a subject. The method involves manipulating image data from the target bodily tissue and a background bodily tissue after dosing the subject with a contrast agent. The relative intensities of the light emitted from selected areas of the target bodily tissue and background bodily tissue at different time points after dosing are compared to determine whether 1) the intensity of light emitted from the target bodily tissue is lower than the intensity of light emitted from the background bodily tissue during the first part of the time period; and/or 2) the intensity of light emitted from the target bodily tissue is higher than the intensity of light emitted from the background bodily tissue during the second part of the time period; to assist in the determination of whether the target bodily tissue is benign or malignant.

[0129] Although a few preferred embodiments have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

[0130] Throughout this specification, the term “comprising” or “comprises” means including the component(s) specified but not to the exclusion of the presence of other components. The term “consisting essentially of” or “consists essentially of” means including the components specified but excluding other components except for materials present as impurities, unavoidable materials present as a result of processes used to provide the components, and components added for a purpose other than achieving the technical effect of the invention.

[0131] The term “consisting of” or “consists of” means including the components specified but excluding addition of other components.

[0132] Whenever appropriate, depending upon the context, the use of the term “comprises” or “comprising” may also be taken to encompass or include the meaning “consists essentially of” or “consisting essentially of”, and may also be taken to include the meaning “consists of” or “consisting of”.

[0133] The optional features set out herein may be used either individually or in combination with each other where appropriate and particularly in the combinations as set out in the accompanying claims. The optional features for each aspect or exemplary embodiment of the invention as set out herein are also to be read as applicable to any other aspect or exemplary embodiments of the invention, where appropriate. In other words, the skilled person reading this specification should consider the optional features for each exemplary embodiment of the invention as interchangeable and combinable between different exemplary embodiments.

[0134] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0135] All of the features disclosed in this specification (including any accompanying claims, and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

[0136] Each feature disclosed in this specification (including any accompanying claims, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0137] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.