STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH

N/A

BACKGROUND

Diagnosing prostate cancer (sometimes referred to herein as PCa) is challenging, in part, due to difficulty in detecting and distinguishing indolent PCa from potentially clinically significant PCa. For example, a histologically assigned Gleason score (GS) is typically used to assess lesion aggressiveness. In general medical practice, such as GS is generated based on a non-targeted template driven transrectal ultrasound-guided (TRUS) biopsy, which results in under-detection of clinically significant PCa. Recently, 3 Tesla-based multi-parametric MRI (3 T mp-MRI) has been used to provide a powerful combination of anatomical and functional information for PCa diagnosis, and can potentially play a pivotal role in the diagnosis of PCa by reducing unnecessary biopsies and adding treatment options in active surveillance and focal therapy. The core components of mp-MRI include T2-weighted imaging (T2w), diffusion-weighted imaging (DWI), and dynamic contrast-enhanced imaging (DCE-MRI), each of which provides distinct information. Current diagnostic practice for mp-MRI follows the Prostate Imaging Reporting and Data System: Version 2 (PI-RADS v2), which evaluates radiologic findings in a qualitative or semi-quantitative manner. However, PI-RADS v2 has a limited ability to detect and distinguish between indolent and clinically significant PCa, with a wide range of sensitivity and specificity, mainly due to inter-reader variability and suboptimal analysis. For example, to interpret prostate mp-MRI and generate radiologic findings that are qualitative requires a high level of expertise, relying on T2 morphology and non-quantitative assessment of diffusion restriction and lesional enhancement. Thus, radiologic findings in one component of mp-MRI are often more observable than in another component.

Accordingly, new systems, methods, and media for automatically segmenting and diagnosing prostate lesions using multi-parametric magnetic resonance imaging data are desirable.

SUMMARY

In accordance with some embodiments of the disclosed subject matter, systems, methods, and media for automatically segmenting and diagnosing prostate lesions using multi-parametric magnetic resonance imaging data are provided.

In accordance with some embodiments of the disclosed subject matter, a system for automatically detecting and classifying prostate lesions is provided, the system comprising: at least one hardware processor that is programmed to: receive multi-parameter MRI (mp-MRI) data depicting a portion of a subject's prostate, the mp-MRI data comprising a plurality of components, wherein a first component of the plurality of components comprises T2 weighted (T2w) data, and a second component of the plurality of components comprises apparent diffusion coefficient (ADC) data; provide the T2w data as input to a first input channel of a plurality of input channels of a trained convolutional neural network (CNN) classification model, wherein the trained CNN classification model is configured to receive inputs using the plurality of input channels, each of the plurality of input channels corresponding to one of the plurality of components, and provide outputs using a plurality of output channels, each of the plurality of output cannels indicating a likelihood that each pixel of the data provided to the input channels corresponds to a particular class of prostate lesion of a plurality of classes, with each class of the plurality of classes corresponding to a predicted aggressiveness of a prostate lesion in order of increasing aggressiveness, and wherein the trained CNN classification model was trained using labeled mp-MRI data comprising a multiplicity of slices of T2w data, and a respective multiplicity of co-registered ADC data, and a combination of focal loss (FL) and mutual finding loss (MFL); provide the ADC data as input to a second channel of the plurality of channels; receive, from the trained CNN classification model for each of a plurality of pixels of the mp-MRI data, a plurality of output values from the respective plurality of output channels, wherein each of the plurality of output values is indicative of a likelihood that a prostate lesion of at least the level of prostate lesion aggressiveness corresponding to that output channel is present at the pixel; identify a prostate lesion in the mp-MRI data based one or more output values for one or more pixels of the plurality of pixels being greater than a threshold; predict an aggressiveness of the identified prostate lesion based on which output channels had values over the threshold for the particular pixel; and cause an indication that a prostate lesion of the predicted aggressiveness is likely present in the subject's prostate to be presented to a user.

In some embodiments, a first output channel of the plurality of output channels is associated with a first class that corresponds to a Gleason score of 3+3, a second output channel of the plurality of output channels is associated with a second class that corresponds to a Gleason score of 3+4, a third output channel of the plurality of output channels is associated with a third class that corresponds to a Gleason score of 4+3, a fourth output channel of the plurality of output channels is associated with a fourth class that corresponds to a Gleason score of 8, and a fifth output channel of the plurality of output channels is associated with a fifth class that corresponds to a Gleason score of 9 or more.

In some embodiments, the CNN classification model was trained at least in part by: (i) providing a slice of training T2w data as input to the first input channel of the untrained CNN classification model, and a slice of training ADC data corresponding to the T2w data as input to the second input channel of the untrained CNN classification model; (ii) receiving from the untrained CNN, a first set of outputs comprising a value from each output channel for each pixel of the training mp-MRI data based on the data provided as input at (i); (iii) generating, using label information associated with the training mp-MRI data, a plurality of binary masks that are each associated with one of the plurality of classes, each mask indicating which pixels of the training mp-MRI data are non-lesion and which pixels of the training mp-MRI data correspond to a lesion of at least the class associated with the mask; (iv) generating a first loss value using FL based on a comparison of the plurality of masks and the first set of outputs for each pixel of the training mp-MRI data; (v) providing the slice of training T2w data as input to the first channel of the untrained CNN classification model, and blank data as input to the second channel of the untrained CNN classification model; (vi) receiving from the untrained CNN, a second set of outputs comprising a value from each output channel for each pixel of the training mp-MRI data based on the data provided as input at (v); (vii) providing blank data as input to the first channel of the untrained CNN classification model, and the slide of training ADC data as input to the second channel of the untrained CNN classification model; (viii) receiving from the untrained CNN, a third set of outputs comprising a value from each output channel for each pixel of the training mp-MRI data based on the data provided as input at (vii); (ix) selecting, for MFL, between the second set of outputs and the third set of outputs based on which of the second set of outputs and third set of outputs more closely corresponds to the first set of outputs; (x) generating a second loss value based on a distance between the plurality of masks and the differences between the first set of outputs and the selected set of outputs; and (xi) repeating (i) to (x) for the multiplicity of training slices to generate the trained CNN classification model.

In some embodiments, a first mask of the plurality of masks corresponds to the first class, a second mask of the plurality of masks corresponds to the second class, a third mask of the plurality of masks corresponds to the third class, a fourth mask of the plurality of masks corresponds to the fourth class, and a fifth mask of the plurality of masks corresponds to the fifth class.

In some embodiments, the at least one hardware processor that is programmed to: clip the T2w data using a lower threshold corresponding to an intensity of air and an upper threshold corresponding to an intensity of bladder in the T2w data; and normalize the clipped T2w data to a range of [0,1].

In some embodiments, the at least one hardware processor that is programmed to: select a portion of the T2w data centered on the prostate depicted in the mp-MRI data; and convert the selected portion of the T2w data to a size corresponding to an input size of the first input channel.

In some embodiments, the at least one hardware processor that is programmed to: provide the T2w data as input to the first input channel of the trained CNN classification model, and blank data as input to the second channel of the trained CNN; receive, from the trained CNN classification model for each of a plurality of pixels of the mp-MRI data, a second plurality of output values from the respective plurality of output channels; provide blank data as input to the first input channel of the trained CNN classification model, and the ADC data as input to the second channel of the trained CNN; receive, from the trained CNN classification model for each of a plurality of pixels of the mp-MRI data, a third plurality of output values from the respective plurality of output channels; select one of the plurality of components, ISel, to segment based on which of the second plurality of output values and the third plurality of output values minimizes the expression

IS⁢e⁢l=arg⁢minc∈{IA⁢D⁢C,IT⁢⁢2⁢w}⁢d⁡(y^⊗fo⁢u⁢t,y^⊗fc),
where IT2wis the T2w data, IADCis the ADC data, ƒoutand ƒcare the plurality of outputs and the second plurality of outputs or third plurality of outputs; and segment the selected component ISelbased on an inferred mask y* that minimized energy E in the expression E(y*)=Σi=1Nϕu(y*|IADC,IT2w)+Σi<jNϕp(y*i,y*j|ISel), where ϕuis the unary potential from a negative log-likelihood of a CNN predicted probability map, and ϕpis the pairwise potential from ith and jth pixels in the CNN predicted probability map.

In accordance with some embodiments of the disclosed subject matter, a method for automatically detecting and classifying prostate lesions is provided, the method comprising: receiving multi-parameter MRI (mp-MRI) data depicting a portion of a subject's prostate, the mp-MRI data comprising a plurality of components, wherein a first component of the plurality of components comprises T2 weighted (T2w) data, and a second component of the plurality of components comprises apparent diffusion coefficient (ADC) data; providing the T2w data as input to a first input channel of a plurality of input channels of a trained convolutional neural network (CNN) classification model, wherein the trained CNN classification model is configured to receive inputs using the plurality of input channels, each of the plurality of input channels corresponding to one of the plurality of components, and provide outputs using a plurality of output channels, each of the plurality of output cannels indicating a likelihood that each pixel of the data provided to the input channels corresponds to a particular class of prostate lesion of a plurality of classes, with each class of the plurality of classes corresponding to a predicted aggressiveness of a prostate lesion in order of increasing aggressiveness, and wherein the trained CNN classification model was trained using labeled mp-MRI data comprising a multiplicity of slices of T2w data, and a respective multiplicity of co-registered ADC data, and a combination of focal loss (FL) and mutual finding loss (MFL); providing the ADC data as input to a second channel of the plurality of channels; receiving, from the trained CNN classification model for each of a plurality of pixels of the mp-MRI data, a plurality of output values from the respective plurality of output channels, wherein each of the plurality of output values is indicative of a likelihood that a prostate lesion of at least the level of prostate lesion aggressiveness corresponding to that output channel is present at the pixel; identifying a prostate lesion in the mp-MRI data based one or more output values for one or more pixels of the plurality of pixels being greater than a threshold; predicting an aggressiveness of the identified prostate lesion based on which output channels had values over the threshold for the particular pixel; and causing an indication that a prostate lesion of the predicted aggressiveness is likely present in the subject's prostate to be presented to a user.

In accordance with some embodiments of the disclosed subject matter, a non-transitory computer readable medium containing computer executable instructions that, when executed by a processor, cause the processor to perform a method for automatically detecting and classifying prostate lesions is provided, the method comprising: receiving multi-parameter MRI (mp-MRI) data depicting a portion of a subject's prostate, the mp-MRI data comprising a plurality of components, wherein a first component of the plurality of components comprises T2 weighted (T2w) data, and a second component of the plurality of components comprises apparent diffusion coefficient (ADC) data; providing the T2w data as input to a first input channel of a plurality of input channels of a trained convolutional neural network (CNN) classification model, wherein the trained CNN classification model is configured to receive inputs using the plurality of input channels, each of the plurality of input channels corresponding to one of the plurality of components, and provide outputs using a plurality of output channels, each of the plurality of output cannels indicating a likelihood that each pixel of the data provided to the input channels corresponds to a particular class of prostate lesion of a plurality of classes, with each class of the plurality of classes corresponding to a predicted aggressiveness of a prostate lesion in order of increasing aggressiveness, and wherein the trained CNN classification model was trained using labeled mp-MRI data comprising a multiplicity of slices of T2w data, and a respective multiplicity of co-registered ADC data, and a combination of focal loss (FL) and mutual finding loss (MFL); providing the ADC data as input to a second channel of the plurality of channels; receiving, from the trained CNN classification model for each of a plurality of pixels of the mp-MRI data, a plurality of output values from the respective plurality of output channels, wherein each of the plurality of output values is indicative of a likelihood that a prostate lesion of at least the level of prostate lesion aggressiveness corresponding to that output channel is present at the pixel; identifying a prostate lesion in the mp-MRI data based one or more output values for one or more pixels of the plurality of pixels being greater than a threshold; predicting an aggressiveness of the identified prostate lesion based on which output channels had values over the threshold for the particular pixel; and causing an indication that a prostate lesion of the predicted aggressiveness is likely present in the subject's prostate to be presented to a user.

In accordance with some embodiments of the disclosed subject matter, a system for determining a class of a cancer is provided, the system comprising: at least one hardware processor that is programmed to: receive multi-parameter imaging data depicting a portion of a subject: provide a first subset of the multi-parameter imaging data as input to a first channel of a trained convolutional neural network (CNN); provide a second subset of the multi-parameter imaging data as input to a second channel of the trained CNN; receive, from the trained CNN, a set of output values corresponding to a set of output channels for a plurality of pixels of the multi-parameter imaging data, the set of output channels corresponding to a set of classes of cancer in order of increasing aggressiveness, and each value indicating a likelihood that the pixel depicts cancerous tissue of at least a particular class of cancer corresponding to the output channel from which the value was output; identify a cancer region in the multi-parameter imaging data based on one or more output values for one or more pixels corresponding to the cancer region being greater than a threshold; predict an aggressiveness of the identified cancer region based on which of the output channels had values over the threshold for one or more pixels; and generate a report indicating that the predicted aggressiveness is present in the cancer region.

