Guidance Core

Noby hata Jayender Jagadeesan Junichi Tokuda
Nobuhiko Hata, PhD
Core Lead
Jayender Jagadeesan, PhD
Project Lead
Junichi Tokuda, PhD
Project Lead

The long-term goal of Guidance Core is to provide novel guidance methods to improve the outcome of therapies of dynamically deforming and moving organs. This involves developing unique tissue-embedded wireless electromagnetic sensors (EM) and MR-tracked catheters to verify their feasibility and impact on the clinical procedures performed at the Advanced Multimodality Image Guided Operating Room (AMIGO). Projects within this Core are:

Integrated navigation system to accurately localize the tumor and guide the surgical instrument to the optimal resection margin in presence of significant tissue deformation.  We are developing hardware for the integrated navigation system to enable real-time tumor and instrument tracking; a tumor deformation model to estimate the tumor position and optimal resection margin; software for the integrated navigation system to visualize the tumor and surgical instrument. We continue to validate the design and performance of the integrated navigation system in ex-vivo phantoms and in human clinical trials. (Contact: Jayender Jagadeesan)

Verify the ability of active MRI-tracked metallic interventional devices to improve interventions through improved positional accuracy and improved therapy delivery. We are developing a miniature MRI tracking coil array embedded in flexible and rigid metallic stylets and catheters and improving dedicated MR-tracking pulse sequences to locate the devices so as to rapidly and accurately guide insertion of these devices in soft tissue and to monitor the non-rigid deformation of the target tissues. This is expected to enable clinicians to correct the access path based on these data. In addition, motional data provided by the devices is expected to aid in motion-compensated oxygenation imaging for radiation-dose augmentation to hypoxic tumor segments that resist radiation therapy. (Contact: Junichi Tokuda)

Software and Documentation


Full Publication List

In NIH/NLM database and in our here.

Select Recent Publications

Gao W, Jiang B, Kacher DF, Fetics B, Nevo E, Lee TC, Jayender J. Real-time Probe Tracking using EM-optical Sensor for MRI-guided Cryoablation . Int J Med Robot. 2018;14 (1).Abstract
BACKGROUND: A method of real-time, accurate probe tracking at the entrance of the MRI bore is developed, which, fused with pre-procedural MR images, will enable clinicians to perform cryoablation efficiently in a large workspace with image guidance. METHODS: Electromagnetic (EM) tracking coupled with optical tracking is used to track the probe. EM tracking is achieved with an MRI-safe EM sensor working under the scanner's magnetic field to compensate the line-of-sight issue of optical tracking. Unscented Kalman filter-based probe tracking is developed to smooth the EM sensor measurements when occlusion occurs and to improve the tracking accuracy by fusing the measurements of two sensors. RESULTS: Experiments with a spine phantom show that the mean targeting errors using the EM sensor alone and using the proposed method are 2.21 mm and 1.80 mm, respectively. CONCLUSION: The proposed method achieves more accurate probe tracking than using an EM sensor alone at the MRI scanner entrance.
Schmidt EJ, Halperin HR. MRI use for Atrial Tissue Characterization in Arrhythmias and for EP Procedure Guidance. Int J Cardiovasc Imaging. 2018;34 (1) :81-95.Abstract
We review the utilization of magnetic resonance imaging methods for classifying atrial tissue properties that act as a substrate for common cardiac arrhythmias, such as atrial fibrillation. We then review state-of-the-art methods for mapping this substrate as a predicate for treatment, as well as methods used to ablate the electrical pathways that cause arrhythmia and restore patients to sinus rhythm.
Jiang B, Gao W, Kacher D, Nevo E, Fetics B, Lee TC, Jayender J. Kalman Filter-based EM-optical Sensor Fusion for Needle Deflection Estimation. Int J Comput Assist Radiol Surg. 2018;13 (4) :573-83.Abstract
PURPOSE: In many clinical procedures such as cryoablation that involves needle insertion, accurate placement of the needle's tip at the desired target is the major issue for optimizing the treatment and minimizing damage to the neighboring anatomy. However, due to the interaction force between the needle and tissue, considerable error in intraoperative tracking of the needle tip can be observed as needle deflects. METHODS: In this paper, measurements data from an optical sensor at the needle base and a magnetic resonance (MR) gradient field-driven electromagnetic (EM) sensor placed 10 cm from the needle tip are used within a model-integrated Kalman filter-based sensor fusion scheme. Bending model-based estimations and EM-based direct estimation are used as the measurement vectors in the Kalman filter, thus establishing an online estimation approach. RESULTS: Static tip bending experiments show that the fusion method can reduce the mean error of the tip position estimation from 29.23 mm of the optical sensor-based approach to 3.15 mm of the fusion-based approach and from 39.96 to 6.90 mm, at the MRI isocenter and the MRI entrance, respectively. CONCLUSION: This work established a novel sensor fusion scheme that incorporates model information, which enables real-time tracking of needle deflection with MRI compatibility, in a free-hand operating setup.
Abayazid M, Kato T, Silverman SG, Hata N. Using Needle Orientation Sensing as Surrogate Signal for Respiratory Motion Estimation in Rercutaneous Interventions. Int J Comput Assist Radiol Surg. 2018;13 (1) :125-33.Abstract
PURPOSE: To develop and evaluate an approach to estimate the respiratory-induced motion of lesions in the chest and abdomen. MATERIALS AND METHODS: The proposed approach uses the motion of an initial reference needle inserted into a moving organ to estimate the lesion (target) displacement that is caused by respiration. The needles position is measured using an inertial measurement unit (IMU) sensor externally attached to the hub of an initially placed reference needle. Data obtained from the IMU sensor and the target motion are used to train a learning-based approach to estimate the position of the moving target. An experimental platform was designed to mimic respiratory motion of the liver. Liver motion profiles of human subjects provided inputs to the experimental platform. Variables including the insertion angle, target depth, target motion velocity and target proximity to the reference needle were evaluated by measuring the error of the estimated target position and processing time. RESULTS: The mean error of estimation of the target position ranged between 0.86 and 1.29 mm. The processing maximum training and testing time was 5 ms which is suitable for real-time target motion estimation using the needle position sensor. CONCLUSION: The external motion of an initially placed reference needle inserted into a moving organ can be used as a surrogate, measurable and accessible signal to estimate in real-time the position of a moving target caused by respiration; this technique could then be used to guide the placement of subsequently inserted needles directly into the target.
Li M, Narayan V, Gill RR, Jagannathan JP, Barile MF, Gao F, Bueno R, Jayender J. Computer-Aided Diagnosis of Ground-Glass Opacity Nodules Using Open-Source Software for Quantifying Tumor Heterogeneity. AJR Am J Roentgenol. 2017;209 (6) :1216-27.Abstract
OBJECTIVE: The purposes of this study are to develop quantitative imaging biomarkers obtained from high-resolution CTs for classifying ground-glass nodules (GGNs) into atypical adenomatous hyperplasia (AAH), adenocarcinoma in situ (AIS), minimally invasive adenocarcinoma (MIA), and invasive adenocarcinoma (IAC); to evaluate the utility of contrast enhancement for differential diagnosis; and to develop and validate a support vector machine (SVM) to predict the GGN type. MATERIALS AND METHODS: The heterogeneity of 248 GGNs was quantified using custom software. Statistical analysis with a univariate Kruskal-Wallis test was performed to evaluate metrics for significant differences among the four GGN groups. The heterogeneity metrics were used to train a SVM to learn and predict the lesion type. RESULTS: Fifty of 57 and 51 of 57 heterogeneity metrics showed statistically significant differences among the four GGN groups on unenhanced and contrast-enhanced CT scans, respectively. The SVM predicted lesion type with greater accuracy than did three expert radiologists. The accuracy of classifying the GGNs into the four groups on the basis of the SVM algorithm was 70.9%, whereas the accuracy of the radiologists was 39.6%. The accuracy of SVM in classifying the AIS and MIA nodules was 73.1%, and the accuracy of the radiologists was 35.7%. For indolent versus invasive lesions, the accuracy of the SVM was 88.1%, and the accuracy of the radiologists was 60.8%. We found that contrast enhancement does not significantly improve the differential diagnosis of GGNs. CONCLUSION: Compared with the GGN classification done by the three radiologists, the SVM trained regarding all the heterogeneity metrics showed significantly higher accuracy in classifying the lesions into the four groups, differentiating between AIS and MIA and between indolent and invasive lesions. Contrast enhancement did not improve the differential diagnosis of GGNs.
Mallory MA, Sagara Y, Aydogan F, Desantis S, Jayender J, Caragacianu D, Gombos E, Vosburgh KG, Jolesz FA, Golshan M. Feasibility of Intraoperative Breast MRI and the Role of Prone Versus Supine Positioning in Surgical Planning for Breast-Conserving Surgery. Breast J. 2017;23 (6) :713-7.Abstract
We assessed the feasibility of supine intraoperative MRI (iMRI) during breast-conserving surgery (BCS), enrolling 15 patients in our phase I trial between 2012 and 2014. Patients received diagnostic prone MRI, BCS, pre-excisional supine iMRI, and postexcisional supine iMRI. Feasibility was assessed based on safety, sterility, duration, and image-quality. Twelve patients completed the study; mean duration = 114 minutes; all images were adequate; no complications, safety, or sterility issues were encountered. Substantial tumor-associated changes occurred (mean displacement = 67.7 mm, prone-supine metric, n = 7). We have demonstrated iMRI feasibility for BCS and have identified potential limitations of prone breast MRI that may impact surgical planning.
Shyn PB, Tremblay-Paquet S, Palmer K, Tatli S, Tuncali K, Olubiyi OI, Hata N, Silverman SG. Breath-hold PET/CT-guided Tumor Ablation under General Anesthesia: Accuracy of Tumor Image Registration and Projected Ablation Zone Overlap. Clin Radiol. 2017;72 (3) :223-9.Abstract

AIM: To assess single-breath-hold combined positron-emission tomography/computed tomography (PET/CT) for accuracy of tumour image registration and projected ablation volume overlap in patients undergoing percutaneous PET/CT-guided tumour-ablation procedures under general anaesthesia. MATERIALS AND METHODS: Eight patients underwent 12 PET/CT-guided tumour-ablation procedures to treat 20 tumours in the lung, liver, or adrenal gland. Using breath-hold PET/CT, the centre of the tumour was marked on each PET and CT acquisition by four readers to assess two- (2D) and three-dimensional (3D) spatial misregistration. Overlap of PET and CT projected ablation volumes were compared using the Dice similarity coefficient (DSC). Interobserver differences were assessed with repeated measure analysis of variance (ANOVA). Technical success and local progression rates were noted. RESULTS: Mean tumour 2D PET/CT misregistrations were 1.02 mm (range 0.01-5.02), 1.89 (0.03-7.85), and 3.05 (0-10) in the x, y, and z planes. Mean 3D misregistration was 4.4 mm (0.36-10.74). Mean projected PET/CT ablation volume DSC was 0.72 (±0.19). No significant interobserver differences in 3D misregistration (p=0.73) or DSC (p=0.54) were observed. Technical success of ablations was 100%; one (5.3%) of 19 tumours progressed. CONCLUSION: Accurate spatial registration of tumours and substantial overlap of projected ablation volumes are achievable when comparing PET and CT acquisitions from single-breath-hold PET/CT. The results suggest that tumours visible only at PET could be accurately targeted and ablated using this technique.

Schmidt EJ, Watkins RD, Zviman MM, Guttman MA, Wang W, Halperin HA. A Magnetic Resonance Imaging–Conditional External Cardiac De brillator for Resuscitation within the Magnetic Resonance Imaging Scanner Bore. Circ Cardiovasc Imaging. 2016;9 :e005091.Abstract

Subjects undergoing cardiac arrest within a magnetic resonance imaging (MRI) scanner are currently removed from the bore and then from the MRI suite, before the delivery of cardiopulmonary resuscitation and de brillation, potentially increasing the risk of mortality. This precludes many higher-risk (acute ischemic and acute stroke) patients from undergoing MRI and MRI-guided intervention. An MRI-conditional cardiac de brillator should enable scanning with de brillation pads attached and the generator ON, enabling application of de brillation within the seconds of MRI after a cardiac event. An MRI-conditional external de brillator may improve patient acceptance for MRI procedures. Methods and Results—A commercial external de brillator was rendered 1.5 Tesla MRI-conditional by the addition of novel radiofrequency lters between the generator and commercial disposable surface pads. The radiofrequency lters reduced emission into the MRI scanner and prevented cable/surface pad heating during imaging, while preserving all the de brillator monitoring and delivery functions. Human volunteers were imaged using high speci c absorption rate sequences to validate MRI image quality and lack of heating. Swine were electrically brillated (n=4) and thereafter de brillated both outside and inside the MRI bore. MRI image quality was reduced by 0.8 or 1.6 dB, with the generator in monitoring mode and operating on battery or AC power, respectively. Commercial surface pads did not create artifacts deeper than 6 mm below the skin surface. Radiofrequency heating was within US Food and Drug Administration guidelines. De brillation was completely successful inside and outside the MRI bore. Conclusions—A prototype MRI-conditional de brillation system successfully de brillated in the MRI without degrading the image quality or increasing the time needed for de brillation. It can increase patient acceptance for MRI procedures.

Tani S, Tatli S, Hata N, Garcia-Rojas X, Olubiyi OI, Silverman SG, Tokuda J. Three-dimensional Quantitative Assessment of Ablation Margins Based on Registration of Pre- and Post-procedural MRI and Distance Map. Int J Comput Assist Radiol Surg. 2016;11 (6) :1133-42.Abstract

PURPOSE: Contrast-enhanced MR images are widely used to confirm the adequacy of ablation margin after liver ablation for early prediction of local recurrence. However, quantitative assessment of the ablation margin by comparing pre- and post-procedural images remains challenging. We developed and tested a novel method for three-dimensional quantitative assessment of ablation margin based on non-rigid image registration and 3D distance map. METHODS: Our method was tested with pre- and post-procedural MR images acquired in 21 patients who underwent image-guided percutaneous liver ablation. The two images were co-registered using non-rigid intensity-based registration. After the tumor and ablation volumes were segmented, target volume coverage, percent of tumor coverage, and Dice similarity coefficient were calculated as metrics representing overall adequacy of ablation. In addition, 3D distance map around the tumor was computed and superimposed on the ablation volume to identify the area with insufficient margins. For patients with local recurrences, the follow-up images were registered to the post-procedural image. Three-dimensional minimum distance between the recurrence and the areas with insufficient margins was quantified. RESULTS: The percent tumor coverage for all nonrecurrent cases was 100 %. Five cases had tumor recurrences, and the 3D distance map revealed insufficient tumor coverage or a 0-mm margin. It also showed that two recurrences were remote to the insufficient margin. CONCLUSIONS: Non-rigid registration and 3D distance map allow us to quantitatively evaluate the adequacy of the ablation margin after percutaneous liver ablation. The method may be useful to predict local recurrences immediately following ablation procedure.