AAPM Multimodality Medical Imaging -I

Transcription

1 Monday, July 28, 2008 Imaging Continuing Education Course CE-Imaging: Multimodality Medical Imaging - I Case History 46 year old female with melanoma. Multimodality Imaging Clinical Perspective PET-CT exam for initial staging. Michael W. Vannier, M.D. University of Radiological Presentations Radiological Presentations

2 Purpose (CANADA) Challenges in diagnostic imaging technology (2008) The evidence gap ; Overuse Economics of diagnostic imaging Oncology; Neuroimaging; Cardiovascular; Orthopedic Identify trends channel CT scanners *NEW* Applications of high end scanners Neuroimaging; Cardiac Imaging; etc. 4D angiography; non-gated scanning Low end CT scanners: Point of Care CT ; DentoMaxilloFacial/ENT CT in the cath lab (high end application to PCI) 5 27 June 2008 Doctors often seem to prescribe CT and MRI scans when they are of little or no medical use, perhaps explaining why Canadians still face hefty delays to get the tests, a new Ontario study suggests. Large percentages of the scans reviewed by the researchers either unearthed no medical problems, or detected abnormalities that would not change how the patient was treated, raising questions about whether they should have been ordered in the first place. Sunday, 29 June 2008

3 US spends more for healthcare Medical spending in the United States has continued to soar, reaching an estimates $2.25 trillion in The nation now spends 50% more on health care per capita than the next closest industrialized country, often with no better outcomes for patients. One reason is overuse of medical technology. The New York Times 29 June 2008 Sources: Centers for Medicare and Medicaid Services, U.S. Department of Health and Human Services, Organization for Economic Cooperation and Development, New York Times Medicare coverage of cardiac computed tomography angiography March 2008

4 Lumbosacral Spine CT 15

5 Recommended Protocol Templates in Excel Spreadsheets 18 Multirow Detector CT (MDCT) Scanner 128 detector rows; 256 slices (ict) Increased Speed, Power, Coverage Nose to Toe Scan:168 cm in 22sec Higher temporal resolution 0.27 sec rotation Increased Tube Power 120 kw / 1,000 ma X-YY and Z focal spot modulation Greater coverage per rotation 8 cm 256 slices

6 Multi-phase Cardiac Imaging less than 5 sec More detectors (rows & channels) channels Faster gantry rotation Higher source brightness 256 channels Focal spot modulation Larger scanner aperture Table weight limit increased Lower dose detector row CT scanners Enables 4D CT angiography & Whole organ perfusion exam 320 channels

7 Non-Gated Chest CT Scan Excellent coronary visualization RT=0.33sec CT Bronchoscopy Non-Gated Scan 25 Metr ohea Large Patient Cardiac CT 13 yr old Female 132kg 162cm 50 BMI 52 bpm 4.8 sec scan 2D Anti-Scatter detector grid improves contrast resolution Smart Focal Spot for artifact elimination BMI = 50 28

8 Head & Neck MRI of Cerebral Ischemia Early DWI/MTT mismatch, lesion growth FSE T2W Initial DWI Initial MTT DWI 5 days later 78 yo female 3 hrs after onset of aphasia during cardiac cath. 31 Greg Sorensen, Massachusetts General Hospital 32 Bernhard Preim, Visualization Research Group, University of Magdeburg, Germany

9 Perfusion CTP MRP T2 DWI MTT CT vs. MRI vs. xenon CT vs. PET vs. SPECT 33 Megan Strother, M.D., Vanderbilt University Non-contrast CT STROKE IMAGING MRI 34 Megan Strother, M.D., Vanderbilt University Imaging Ischemia--Vascular Angiogram s (pre-ct era) Imaging Ischemia- Parenchyma Head CT Vascular occlusion 24 hours No ICH <1/3 MCA territory Thrombolysis <3 hours Recanalization = Clinical improvement IV Thrombolysis 35 Megan Strother, M.D., Vanderbilt University 36 Megan Strother, M.D., Vanderbilt University

10 Vascular Occlusion Tissue Clock CBF Wall Clock MTT Parenchymal changes on non-contrast CT CBV. 37 Megan Strother, M.D., Vanderbilt University MR MR No radiation Better contrast vs. CT 38 Megan Strother, M.D., Vanderbilt University CT A d v a n t a g e M R MR Diffusion = Infarct MR = 94% sensitive and 96% specific for infarct Non-contrast CT = 50% accurate for acute infarct 39 Megan Strother, M.D., Vanderbilt University CT A d v a n t a g e M R MR 40 Megan Strother, M.D., Vanderbilt University CT MR = whole-brain coverage CT limited by scanner (10-40 mm max) Post fossa obscured on CT by beamhardening artifact A d v a n t a g e M R

11 CT Speed Accessibility Spatial Resolution on CTA MR 41 Megan Strother, M.D., Vanderbilt University A d v a n t a g e C T CT MR Quantifiable MR relies on indirect T2* effects on tissue from gad, therefore not quantifiable 42 Megan Strother, M.D., Vanderbilt University A d v a n t a g e C T fast CTA vascular detail accessible CTP quantifiable cheap STROKE IMAGING whole-brain coverage no radiation diffusion MRP CT Scan Protocol 1 st Non-contrast Head CT 2 nd CT Perfusion 3 rd 43 Megan Strother, M.D., Vanderbilt University CT angiogram 44

12 Head & Neck 45 CT Scanning Protocol 320 Channel Whole Head Dynamic CTA (Multiple Phases) (16 cm z-axis coverage)

13 Whole Brain Perfusion (16 cm z-coverage) Whole Brain Perfusion 256 to 320 Channel MDCT Scanner (2008) 8-16 cm z-axis z coverage is well suited to evaluation of cerebrovascular disease, in stroke (arterial & venous) Whole brain perfusion examination is new Dynamic whole-head head CT angiography with high temporal resolution Bone subtraction petrous ICA, V4, stents Single 50 ml IV contrast material bolus injection Combined with CTA of the supra-aortic aortic vessels Renal CT Angiography (CTA) Renal artery stenosis, trauma, transplant donor, neoplasm But NOT renal function

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15 CT of the kidneys: current status Highest spatial resolution (0.5 mm) (Coppenrath EM et al. Eur Radiol 2006; 16: ) Bi-/tri-phasic imaging - high sensitivity for neoplasia (Walter C et al. Br J Radiol 2003; 76: ) CT urography - replacing conventional urograms (Jung DC et al. Radiographics 2006; 26: ) Challenges: Renal function (perfusion, clearance)? (Daghini E et al. Radiology 2007; 243: ) CH A RITE CONE BEAM CT Hitachi MercuRay NewTom QR Xoran/ISI DentoCAT,, Ann Arbor, MI J. Morita 3DX Accuitomo 60

16 Diagnostic Imaging Facial to Palatal Distal to Anterior Distal to Anterior Facial to Palatal Dentomaxillofacial Images Sagittal MPR Panoramic 63 64

17 8-Slice Portable CT Scanner Compact, lightweight, mobile, high speed, battery and line powered multi-slice CT scanner 25 cm field of view, primarily head and neck. Up to 8 slices per revolution Wireless image transfer system (WITS) Non-contrast head CT; CTA; CTP Slice Portable CT Scanner Radiation Data 67 68

18 CT Scanner for ENT Office / Clinic Manufacturer claims Follow-up to surgery Low X-Ray Radiation Dose R L Sinus CT with a full-body scanner Adult: msv Child: msv BUC LING Sinus CT with the MiniCAT low-dose scanner Adult: 0.13 msv (7-15 x lower radiation dose) Child: 0.07 msv (14-28 x lower radiation dose) R L 71 72

19 This is the same pt scanned within 24 hours using the Ceretom portable scanner and then our GE stationary scanner Which do you prefer? Ceretom Ceretom GE GE Another Clinical Example. Patient 500lb 38 year old African American male Symptoms Aphasia and right sided hemiparesis. Issues No hospital in NYC willing to scan a patient over 400lbs. Patient went 5 days without a CT scan. Imaging Large MCA infarct with mass effect & midline shift. Cerebrovascular Evaluation CBF CTA Direct coronal imaging CBV MTT Direct coronals CT Perfusion (CTP) axial, 1 cm slice, 1 slice/second, acquisition time is user defined (30-40 seconds) reconstruction on the scanner in real time

20 Direct Coronal Facial CT 4 months apart, same Pt, same dose, same recon settings CereTom GE Lightspeed Summary Advantages of Portable CT Imaging Mobile and easy to move (unlike the patient!) Easy to operate for hospital & office personnel Plugs into 120v wall power outlet; or battery Compact & does not require room shielding Performs axial and coronal images; can provide sagittal reconstructions if needed; can provide CTA and 3D images. Compatible with surgical navigation units. Medical Imaging Workstations 79 Thick Client expensive, with substantial local processing capability Thin Client small, portable Accessible throughout enterprise 80

21 Revolution in thin-client solutions Adding applications and 3D to viewing Thin Client Solutions CT viewing plus CT Scan Room Tech at scanner CT Control Room Workspace Portal PACS Department Workstations Comprehensive Cardiac Analysis Brain perfusion-summary maps CT Angiography Applications - AVA Stenosis and Stent Planning Lung Nodule Assessment Virtual Colonography All Key Clinical Applications 3D Tech at Workstation Cath or EP Lab 3D Lab Any chair of your choice Home Integrating CT into the Cath Lab Current and Future Applications John C. Messenger, MD, FACC

22 3-D Features of a Coronary Tree Derived from CTA or 2-D Projection Images Proximal RCA Radius of curvature=34.4 Length=4.27 cm 3-D Model Distal RCA Radius of curvature=22.0 Length=2.62 cm A New Paradigm for Coronary Intervention Complete Diagnostic Imaging Study (CTA) Showing Need for PCI Perform PCI Case Specific Selection of Equipment and Working Views Mid RCA Radius of curvature=30.8 Length=3.90 cm Messenger, Chen, Carroll, Burchenal, Kioussopoulos, Groves. 3-D coronary reconstruction from routine single-plane coronary angiograms: Clinical validation and quantitative analysis of the right coronary artery in 100 patients. International. J. Cardiac Imaging Analyze 3-D Coronary Artery Tree Predict PCI Difficulty and Patient Risks 86 Use of 3D coronary analysis for procedural planning of PCI 87 88

23 51 Y/O, 180 lb female with newly diagnosed infiltrating ductal carcinoma of the right breast and one positive lymph node. ER (+), PR(+). J. Boone, UC Davis Bernhard Preim, Visualization Research Group, University of Magdeburg, Germany 92 Bernhard Preim, Visualization Research Group, University of Magdeburg, Germany

24 Conclusion Diagnostic imaging is subject to overuse with limited evidence for a beneficial effect on outcomes in some applications (e.g., cardiac) Imaging modalities (e.g., CT scanners) are becoming both more and less expensive Low end scanners are available at the Point of Care High end specialty imaging (e.g., CT in the cath lab) is in development Acknowledgments John Steidley, Ph.D., Philips Medical Systems GE Healthcare, Inc. Siemens Medical Solutions, Inc. Diego Ruiz, Johns Hopkins Hospital Predrag ( Pedja ) Sukovic, Xoran Technologies, Inc. Bernhard Preim, University of Magdeburg, Germany John C. Messenger, MD, FACC, University of Colorado Megan Strother, MD, Vanderbilt University Patrik Rogalla, MD, Charite Berlin Alisa Gean, MD, UCSF Radiology David Rosenblum, DO, Case Western Reserve Univ