PETER VOCK 8th Annual Congress Turkish Thoracic Society Antalya, April Virtual bronchoscopy THORACIC IMAGING IN LUNG DISEASE:

Morphology in medicine and in photography Function weather? temperature? wind? functional stenosis? resistance? ?

TYPES OF FUNCTIONAL ANALYSIS: MORPHO- LOGY GRAVITY META- BOLISM inflammation proliferation META- BOLISM inflammation proliferation * PER- FUSION VENTI- LATION early dis. detection reg.physiology airways disease vascul. dis.(PE) treatment guidance W. Gefter: Functional CT imaging of the lungs, Acad Radiol 2002;9:127 Changes over time (motion, growth, regression) *Cellular/molecularfunction CT nowadays still mostly morphological!

- spiral isotropic scanning - multiple detector rows „multislice CT“ 1 gantry rotation  images advantages: - faster volume scan - better resolution: thin slices - larger volume / same time Tube Tube 2-64 >1000 CT of the chest: fast global morphology

Scanner # # rows of sc slice sl effect. ri recon. pitch type channels detectors collimat. thickness interval feed/rot*ch sequential  sc  sc - SS spiral SS  1.25  < sc spiral MS  sc  < sc /.75  sc  < sc / – 4/8 CT DEVELOPMENT: detectors + parameters

16-ch CT PROTOCOL FOR AIRWAYS 1.SCANNING: 16 x (0.625-)1-2 mm, pitch ca. 1.3, low dose 2.Preprogrammed image reconstruction mm thick axial + coronal images (soft kernel) noisy * mm axial images (soft kernel) noisy * 2.3. on demand: small FOV pulmonary arteries etc mm axial images, unilateral FOV for HRCT (HR kernel) usually overlapping (ri < sl) Scan once, get everything! * for postprocessing

LARGE DATA - IMAGE DISPLAY follow up comparison old/precontr. current/contr. 1 image / 3 s: 500 images ---> 25 min vs. successive vs. combined „tile“ „stack“ „tile + stack“ move by segment/screen move by 1 / (subtr.) 1 or 2 monitors cine 3/s ---> 2.8 min.

2D / 3D VIEWING OF LARGE 3D DATA 2 D methods  axial slices (HRCT) multiplanar reformation (MPR) ( sagittal, coronal, oblique, curved, paddle wheel) 3 D methods  simultaneous MPR maximal intensity projection (MIP) (minimal intensity projection) surface shaded display (SSD) volume rendering (VR) virtual endoscopy (VE) ( perspective stereoscopic viewing)

thin or thick slab 3D DISPLAY: MIP, miP maximal (minimal) intensity projection

segmentation by threshold value(s) surface display from any angle light source 3D DISPLAY: Surface shaded display (SSD)

3D DISPLAY: volume rendering (VR) - density info. - data >> SSD - flexible

MIP, min IP SSD VR (threshold = 7) min IP MIP VR (colour transition for density range, variable opacity) SSD VE

1 deposit cursor 2 choose viewing direction 3 define viewing angle 4 adapt threshold Technique of VB

- 950 wer selection of threshold

threshold: -650 HU threshold: +250 HU intraarterial pos. intratracheal pos. Virtual endoscopy: choice of position + threshold for - bronchoscopy and for - pulmonary arterioscopy

1 deposit cursor 2 choose viewing direction 3 define viewing angle 4 adapt threshold 5 advance step by step 6 join views to produce a movie Technique of VB

(variation of SSD/VR) VIRTUAL ENDO- SCOPY (VE) R L ant.

3D DISPLAY: virtual arterioscopy (variation of SSD/VR)

polyp of vocal cord ca of aryepiglottic fold Laryngeal applications of VB

Tracheal applications of VB stenosis post tracheo- tomy intra- thoracic goiter

NHL, 4y m L pulm art sling, 12 y f

carcinoid tumor RUL Bronchial applications of VB

carcinoid tumor RUL: retrograde VE beyond bronchoscopic occlusion -400

NSCLC LUL, 73y f grade 2 stenosis

Lung ca RUL  LM br.

Multidetector CT virtual bronchoscopy to grade tracheobronchial stenosis H. Hoppe, B. Walder, M. Sonnenschein, P. Vock, HP Dinkel AJR 2002;178: Grading airway stenosis down to the segmental level using virtualbronchoscopy H. Hoppe, HP Dinkel, B. Walder, G vAllmen, M. Gugger, P. Vock Chest 2004;125: channel-CT, 4x2 mm sensitivity specificityaccuracy n= 200 bronchial sections90.9%98.9%98.0% (15 ca patients + 5 normal bronchoscopies) grading correlation: r=0.91,>axial,MPR 4-channel-CT, 4x1 mm sensitivity specificityaccuracy grade Central airways (n=176)90.0%96.6%95.5% r=0.87 Segmental airways (n=302)90.0%95.6%95.5% r=0.61

ca of esophagus, fistula

esophagobronchial fistula esophagus L main bronchus ca of esophagus, esophagobronchial fistula

widely angulated view with RUL / RLL bronchus origins Middle lobe syndrome

inflammatory stenosis, empyema Meta analysis - sensitivity 84% (78-89%) - specificity 75% (62-85%) -discriminating for stenosis of different etiol. CM Jones, Ann Thorac Surg 2005;79:365 Benign disease - Lung transplantation - Wegener‘s granul.

Virtual (VB) vs. flexible bronchoscopy (FB) MethodVBFB Advantagesfast, non-invasivedynamic info beyond surfaceshows colors info beyond occlusion biopsy multislice CT: retrospect. treatment Disadvantagesstatic informationsedation required radiation exposurediscomfort mucus-tissue? (threashold*) no biopsy/treatment VB and FB usually are not competitive, used in different clinical situations VB always in comparison with axial and reformatted images *(-520to-720HU)

CONCLUSION VIRTUAL BRONCHOSCOPY - way of looking at data - to be correlated with sections - complimentary to FOB - clinically useful 3D view (postproc.) to see beyond stenosis when FOB not possible in lung transplants (dehisc.)