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Optimizing Thoracic Imaging. July 1, 2009 NSMC Radiology Department Meeting Bruce G. Stewart, MD Radiologist Commonwealth Radiology Associates. Presentation Originally Prepared for NSMC ED Staff and Presented to them at their Faculty Meeting on June 18, 2009. Objectives.

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Optimizing thoracic imaging

Optimizing Thoracic Imaging

July 1, 2009

NSMC Radiology Department Meeting

Bruce G. Stewart, MD

Radiologist

Commonwealth Radiology Associates


Presentation Originally Prepared for NSMC ED Staff and Presented to them at their Faculty Meeting on June 18, 2009


Objectives
Objectives Presented to them at their Faculty Meeting

  • Review types of thoracic CT/CTA exams

  • Show examples of thoracic pathology

  • Optimize ordering of CT scans to answer clinical question

  • Reduce radiation exposure by accurate ordering


Importance of history
Importance of History Presented to them at their Faculty Meeting

  • Allows us to tailor the exam with accurate protocoling

  • Allows us to answer your clinical question most appropriately

  • Minimizes inaccurate interpretation

  • Minimizes repeat exams & unnecessary radiation exposure

  • Include:

    • Signs & Symptoms

    • Diagnosis in Question


Ed ct scanner
ED CT Scanner Presented to them at their Faculty Meeting

  • GE 64 Slice Volume CT

  • Fast scanner!

    • Whole body trauma CT in 10 seconds

    • Reduces cardiac motion, respiratory motion & patient motion

  • Thinner slices

    • Better reformats

    • More confident diagnosis

  • Less contrast needed


Types of chest ct cta
Types of Chest CT/CTA Presented to them at their Faculty Meeting

  • General Chest CT (I- or I+)

  • Chest CTA for Pulmonary Embolus (I+)

  • Chest CTA for Aortic Dissection (I- & I+)

  • HRCT Chest CT for Interstitial Lung Disease (I-)


General chest ct
General Chest CT Presented to them at their Faculty Meeting

  • I-: Foreign body, granuloma, calcified nodule, ? Nodule on CXR, contrast allergy, low eGFR

  • I+: Lung cancer, metastatic disease, lymphoma, mediastinal disease, adenopathy, trauma, SVC obstruction, abscess, empyema, pleural effusion, nodules

  • When in doubt, give contrast


General chest ct1
General Chest CT Presented to them at their Faculty Meeting

  • Data Sets:

    • 5 mm standard algorithm

    • 5 mm lung algorithm

    • 0.63 – 1.25 mm axial data

    • Sagittal & Coronal Reformats

  • 60 cc IV contrast @ 3 cc/sec

  • 30 Second Delay (Slightly arterial phase)


Calcified granuloma
Calcified Granuloma Presented to them at their Faculty Meeting


Pneumonia
Pneumonia Presented to them at their Faculty Meeting


Pneumocystis pneumonia
Pneumocystis Pneumonia Presented to them at their Faculty Meeting


Primary lung cancer
Primary Lung Cancer Presented to them at their Faculty Meeting


Rul rml adenocarcinoma with mediastinal adenopathy
RUL/RML Adenocarcinoma with Mediastinal Adenopathy Presented to them at their Faculty Meeting


Lung abscess
Lung Abscess Presented to them at their Faculty Meeting


Septic emboli in ivdu with pyopneumothorax
Septic Emboli in IVDU with Pyopneumothorax Presented to them at their Faculty Meeting


Pe cta
PE CTA Presented to them at their Faculty Meeting

  • 60 cc IV contrast @ 5-6 cc/sec

  • Timed to Opacify the Pulmonary Arteries

  • Data sets:

    • 1.25 mm standard algorithm

    • 5 mm lung algorithm

    • Sagittal and coronal MIP reformats

    • Rotational MIP images at pulmonary trunks


Saddle pulmonary embolus with infarction
Saddle Pulmonary Embolus Presented to them at their Faculty Meeting with Infarction


Left interlobar pulmonary artery embolus
Left Interlobar Presented to them at their Faculty Meeting Pulmonary Artery Embolus


Left main pulmonary artery pulmonary embolus
Left Main Pulmonary Artery Presented to them at their Faculty Meeting Pulmonary Embolus


Chronic pe with bronchial collaterals
Chronic PE with Bronchial Collaterals Presented to them at their Faculty Meeting


Pe cta is not a better chest ct
PE CTA is Not a Presented to them at their Faculty Meeting “Better Chest CT”

  • Ideal exam if concern is for PE

  • Suboptimal for mediastinal pathology

    • Timing is early so makes detection of lymphadenopathy more difficult

  • Staging & comparison to prior chest CTs more difficult

    • Scan direction is from lung bases to apices

    • Thin collimation (1.25 vs 5 mm)

    • “Granier/Noisy” Image

  • Covers less of upper abdomen


Aortic dissection cta
Aortic Dissection CTA Presented to them at their Faculty Meeting

  • Data sets:

    • Noncontrast chest CT

      • 5 mm standard algorithm

    • Contrast chest CTA

      • 2.5 mm standard algorithm

      • 1.25 mm standard algorithm

      • 5 mm lung algorithm

      • Sagittal and coronal MIP reformats

  • 80 cc IV contrast @ 5 cc/sec

  • Timed to opacify the ascending aorta

  • Can be extended into abdomen


Intramural hematoma
Intramural Hematoma Presented to them at their Faculty Meeting


Type a aortic dissection
Type A Aortic Dissection Presented to them at their Faculty Meeting


Type b aortic dissection
Type B Aortic Dissection Presented to them at their Faculty Meeting

Curved Reformat


Intramural hematoma resolution dissection
Intramural Hematoma -> Resolution -> Dissection Presented to them at their Faculty Meeting


Opacification of pulmonary arteries vs aorta
Opacification of Pulmonary Arteries vs Aorta Presented to them at their Faculty Meeting

  • NSMC protocols are tailored to evaluate the pulmonary arteries OR aorta

  • Sometimes may be able to evaluate both, but often not

  • Variables:

    • Cardiac output

    • IV contrast dose

    • Bolus timing

    • Quality of IV, etc


Opacification of pulmonary artery vs aorta
Opacification of Pulmonary Artery vs Aorta Presented to them at their Faculty Meeting


Triple rule out
Triple Rule-out? Presented to them at their Faculty Meeting

  • Much talked about CTA to rule out pulmonary embolus, aortic dissection and coronary occlusion

  • Currently not performing coronary CTA at NSMC


Minimizing radiation
Minimizing Radiation Presented to them at their Faculty Meeting

  • ALARA (As Low as Reasonably Achievable) Principle

  • Especially Important for Pediatric & Younger Adults

  • Multi-Detector CT (MDCT)

    • Thinner collimation/Overlapping images have better image quality but increase radiation dose

    • Technical innovations to help decrease radiation exposure include dose modulation (auto MA)

    • Higher radiation with increased number of passes/phases


Effective dose
Effective Dose Presented to them at their Faculty Meeting

  • Measure of stochastic risk (carcinogenesis & hereditary risk) of non-uniform exposure to ionizing radiation

    • Measured in milliSieverts (mSv)

  • Allows comparison of the risk estimates associated with partial or whole-body radiation exposures

    • Incorporates different radiation sensitivities of the various organs in the body

    • Based on a tissue weighting factor (Chest = 0.019)

  • Average “Effective Dose" from natural background radiation is 3 mSv per year in the United States

Food & Drug Administration


Effective doses in ct and radiographic examinations
Effective doses in CT Presented to them at their Faculty Meeting and radiographic examinations

International Commission on Radiation Protection, Publication 87


Effective doses in ct and radiographic examinations1
Effective doses in CT Presented to them at their Faculty Meeting and radiographic examinations

Food & Drug Administration


Effective doses at salem hospital may 24 2009 june 8 2009
Effective doses at Salem Hospital Presented to them at their Faculty Meeting May 24, 2009 – June 8, 2009

  • Includes ED Patients, Inpatients & Outpatients

  • Effective Dose = Dose Line Product * Tissue Weighting Factor (0.019)

  •  5 Thoracic Aorta CTAs excluded due to concurrent abdominal scanning


Summary
Summary Presented to them at their Faculty Meeting

  • Proper CT protocoling is important to optimally answer clinical question and to avoid excess radiation

  • Timing of contrast opacification is different for PE CTA vs Aortic Dissection CTA

  • PE CTA is not a “Super Chest CT”

  • Higher radiation dose with multiphase CT exams (ie Aortic Dissection CTA)

  • ALARA

  • Providing history helps us to help you


Questions
Questions? Presented to them at their Faculty Meeting

  • If you don’t know which exam to order or how to order it, please ASK!

  • A Radiologist is in-house from 7:30 AM – 8 PM 7 days/week and on call through the night

  • Consultation:

    • Salem: x 4083

    • Union: x 3538


References
References Presented to them at their Faculty Meeting

  • British Journal of Radiology (2007) 80, e50-e53

  • Schoepf, U. J. et al. Circulation 2004;109:e220-e221

  • Circulation. 2003;107:e224-e225

  • CHEST APRIL 2002 VOL. 121 NO. 4 1377-1378

  • Eur Respir J 2003; 21:374-376

  • AJR 2006; 187:W7-W14

  • RadioGraphics 2004;24:1219-1238

  • AJR 2006; 186:S414-S420

  • RadioGraphics 2005;25:157-173

  • International Commission on Radiation Protection, Abstract ICRP Publication 87

  • www.FDA.gov

  • Hansell, D. M. et al. Radiology 2008;246:697-722\

  • Radiology 2003;228:395-400

  • Shim, S. S. et al. Am. J. Roentgenol. 2006;186:639-648

  • Hagan, I. G. et al. Radiographics 2007;27:919-940

  • Kinoshita, F. et al. Am. J. Roentgenol. 2006;187:926-932

  • Frazier, A. A. et al. Radiographics 2008;28:883-899

  • Hayter, R. G. et al. Radiology 2006;238:841-852

  • Restrepo, C. S. et al. Radiographics 2007;27:1595-1610

  • Radiographics. 2000;20:43-58

  • Sharma, A. et al. Radiographics 2004;24:419-43


Questions raised from presentation to ed staff
Questions Raised from Presentation to ED Staff Presented to them at their Faculty Meeting

  • Possibility of a reliable double rule out?

  • Eliminating noncontrast exam for dissection exams?

    • Bring patient back in setting of dissection now that scanner is in the ED?

  • Reducing dose from dissection exam?

    • Use of 120 vs 140 kV

    • Routinely image/not image abdomen?


Other impressions from presentation to ed staff
Other Impressions from Presentation to ED Staff Presented to them at their Faculty Meeting

  • Generally happy with service of NSMC Radiology

    • Bennett Shamsai

  • Radiation figures got their attention

  • Looking for feedback

    • “How are we doing?”

    • “What are we doing wrong?”

  • Open to Communication