n0102 SPIE1

Experiments in Virtual-Endoscopic Guidance of Bronchoscopy: 

2University of Iowa Iowa City, IA 52246 James P. Helferty1 Anthony J. Sherbondy1 Atilla P. Kiraly1 Janice Z Turlington1 Eric A. Hoffman2 Geoffrey McLennan2 William E. Higgins1,2 SPIE 2001 San Diego, CA 18 February 2001 1Penn State University University Park, PA 16802 Experiments in Virtual-Endoscopic Guidance of Bronchoscopy

Introduction: 

Overview of virtual bronchoscopy and our system (Virtual Navigator) Stage-1 CT-only Pre-Procedure Planning Stage-2 Bronchoscopy examples: Phantom case Animal studies Human case Introduction

Problem Domain: 

Endoscopic Lung biopsy often fails. since anatomy not visible in endoscopic video. Solution: Augment endoscope with rendered CT. ROI seen in CT and not in video Matching Camera Characteristics CT Scan Videoendoscopy Problem Domain

Overview of Virtual Navigator: 

Overview of Virtual Navigator Bronchoscope CT Scan Data Sources Image Processing Analysis HTML Multimedia Case Report Site List Segmented Airway Tree Centerline Paths Screen Snapshots Recorded Movies Physician Notes Stage 1: 3D CT Assessment Identify Target Sites Segment Airway Tree Calculate Centerline Path Virtual Endoluminal Movies Cross-Section Area Calculations Volume Slices, Slabs, Projections Stage 2: Live Bronchoscopy Capture Endoscope Video Correct Barrel Distortion Interactive Virtual Views Register Virtual CT to Video Draw Target Regions on Video

Proposed Virtual Navigator: 

Complete CT examination Guide live bronchoscopy Automate steps in CT assessment Inexpensive, PC-based Proposed Virtual Navigator

Elements of a Case Study: 

Reporting Abstractions Snapshots Plots Movies Case Notes Measurements Data Sources 3D CT Image Bronchoscopic Video Data Abstractions Root Site Key Sites Paths Tree Elements of a Case Study

Examination Stages: 

Build complete Case Study. Compute guidance data. View Endoluminal Movies. Load Case Study. Set up graphical tools. Perform virtual-guided bronchoscopy. Examination Stages

Virtual Navigator Tools: 

Virtual Navigator Tools

Virtual Navigator Tools: 

Virtual Navigator Tools

Stage 2: Virtual Guidance of Live Bronchoscopy: 

LIVE bronchoscope video Video Match Tool shows a matched point between Corresponding videobronchoscopy (ROI superimposed) Virtual data guides airway traversal. Coronal Projection shows extracted airway tree CT rendering of airway region (ROI rendered) Stage 2: Virtual Guidance of Live Bronchoscopy

Experimental Results for Three Bronchoscopy Studies: 

Phantom Animal Human Experimental Results for Three Bronchoscopy Studies

Phantom Experiment: 

Rubber phantom Experimental set-up: physician was blind to phantom Phantom Experiment Target ROIs Controlled test using a non-breathing subject.

Composite View during Phantom Experiment: 

Composite View during Phantom Experiment

Numerical Results from Phantom Experiment: 

Average biopsy error: 1.98 mm Average match time: 11.065 sec. Numerical Results from Phantom Experiment

Composite View during Animal Experiment: 

Composite View during Animal Experiment Live bronchoscopy test using a living subject. Registered virtual shot Matched video frame with ROI

Results of Animal Experiment: 

Snapshots are misaligned to compensate for differing placement during CT scanning. Note: Actual site after dart marker placement. Planned site from CT analysis. Results of Animal Experiment Darts placed directly above targets as expected.

Misguidance in Animal Experiment: 

Snapshots are misaligned to compensate for differing placement during CT scanning. Note: Actual site after dart marker placement. Planned site from CT analysis. Misguidance in Animal Experiment Darts placed one generation before target due to range ambiguity Matching view to this ROI target

Stage 2: Live Human Bronchoscopy: 

Stage 2: Live Human Bronchoscopy

Composite View during Human Bronchoscopy: 

Bronchoscope video matched to rendered CT during live procedure. Composite View during Human Bronchoscopy

Conclusions: 

Conclusions Stage 1 took 5 minutes in experiments. Controlled experiment showed accurate biopsies. System showed capability in live experiments. Bronchoscopic guidance has been improved. Further complete human studies to come.