Percutaneous techniques are becoming more widely adopted for treating solid organ tumours. With many of these techniques using image guidance, accuracy is essential to reduce the risk of complications and tumour recurrence. We propose a novel approach to needle trajectory forecasting using a 3D U-Net trained on interventional computed tomography (iCT) images from renal cryoablation procedures. The U-Net is trained to predict future needle locations from present iCT images, supervised by ground truth labels at future time points. Furthermore, we demonstrate that forecasting needle trajectory may be substantially improved by Monte Carlo dropout (MCDO), in addition to generating uncertainty maps of the predictions. With 122 training iCT volumes, a Dice coefficient of 0.48 on highly elongated needle morphology was achieved based on 41 unseen test cases, significantly outperforming two models not using MCDO at inference with Dice scores of 0.14 and 0.32. MCDO also greatly improved the predicted needle morphology and was able to incorporate directional information into the predictions. Our approach shows promise for improving accuracy and workflow in image-guided procedures, with an interesting research direction to predict uncertain future interventional events by ensemble in supervised approaches.
Percutaneous cryoablation is becoming more popular for the treatment of renal cell carcinoma. Interventional computed tomography (iCT) is commonly used for guidance but reducing radiation dose and increasing slice thickness makes super-resolution (SR) essential for improving image quality. The proposed method takes low quality (LQ), thick slice images and converts them to high quality (HQ), thin slice images while performing denoising and partial volume correction in the z-direction. As LQ and HQ iCT images are challenging to pair up, we train a 3D U-Net equipped with an up-sampling module on simulated LQ (sLQ) data and then test on the real LQ (rLQ) images with cubic interpolation and random forest as comparison. During validation on sLQ data, the U-Net outperformed interpolation and random forest (SSIM 0.9991 vs 0.9959 and 0.9985 respectively), but performance suffered when testing on the out-of-distribution rLQ images. The Dice score showed a substantial improvement when used to compare needle segmentations performed on U-Net generated images versus those from interpolation and random forest (0.4073 vs. 0.2919 and 0.3777 respectively), indicating that the U-Net is reducing the z-direction partial volume effect to a greater degree than these techniques. We have shown that a neural network trained to perform SR on simulated data outperforms interpolation and random forest on real data in terms of localisation of clinically relevant objects such as needles, despite the differing data distribution.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.