CT ANGIOGRAPHY Dr Mohamed El Safwany, MD

Intended learning outcome The student should learn at the end of this lecture CT IMAGE OF THE BLOOD VESSEL OPACIFIED BY CONTRAST.

CT IMAGE OF THE BLOOD VESSELS OPACIFIED BY CONTRAST

REQUIREMENTS FOR CTA PATIENT PREPARATION ACQUSITION PARAMETERS CONTRAST MEDIUM ADMINISTRATION POSTPROCESSING TECHNIQUES

PATIENT PREP.

INFORMED CONSENT

PATIENT PREP. CREAT –1.2 mg/dl IODINE ALLERGY- STEROID THERAPY HYPERVENTILATION BEFORE EXAM FOR BETTER BREATHOLD

UTILIZED

GAUGE SUITABLE FOR CTA 18 OR 20

CONTRAST ADMINISTERED WITH POWER INJECTOR

ACQUSITION PARAMETERS

PARAMETERS USUALLY ROUTINE CT PRECEDES A CTA EXAM. THE ROUTINE EXAM IS USED AS A REFERENCE SCAN HELPING TO DETERMING THE SCANNING RANGE IN CTA.

SLICE THICKNESS SPATIAL RESOLUTION

CEREBRAL CTA ABDOMINAL CTA THORACIC CTA 1MM (LOWER mA) 3MM SLICE THICKNESS

SPIRAL PITCH PITCHSPATIAL RESOLUTION

SPIRAL PITCH UP TO 2

kVp, mA, TIME SIMILAR TO NON- CTA EXAM OF THE SAME BODY PART

RECONSTRUCTION INTERVAL 50% OF OVERLAP

CONTRAST ADMINISTRATION

POWER INJECTOR

POWER INJECTOR PARAMETERS VOLUME OF CONTRAST-ml RATE ml/sec TIME OF INJECTION – sec SCAN DELAY TIME - sec

CONTRAST WARMER WHY???

RATE OF INJECTION 3-5 ml/sec

ORAL CONTRAST???? WATER NEGATIVE CONTRAST

AUTOMATED CONTRAST ADMINISTRATION SYSTEMS SMARTPREP CARE SURESTART

CONTRAST ADMINISTRATION AND SCANNING METHODS BOLUS TRACKING BOLUS TIMING MANUAL PRESET TIME

CARE BOLUS

SMART PREP

Bolus tracking- PE

PE?

Tracking slice

Bolus tracking- Carotids and Circle of Willis

Circle of Willis

Circle of Willis?! 40 SEC

Renal arteries sec.

ABDOMINAL AND FEMORAL RUNOFF

MANUAL DELAYS CERBRAL CTA CAROTID CTA CHEST CTA (PE) 15 SEC 12 SEC SEC

CARDIAC CT

TWO TECHNIQUES TO REDUCE MOTION ARTIFACTS IN CARDIAC CT PROSPECTIVE TRIGGERING RETROSPECTIVE GATING

Prospectively ECG-Triggered Sequential Scanning Cardiac CT applications require the synchronization of data acquisition to the cardiac cycle, i.e. to the movement of the heart. For sequential imaging, a prospective trigger is derived from the ECG-trace to initiate the CT-scan with a certain delay time after the R-wave. Usually, the delay is defined such that the scans are acquired during the diastolic phase of the heart

Retrospectively ECG-Gated Spiral Scanning For "retrospectively ECG-gated spiral scanning" a continuous spiral scan is acquired with the ECG- signal recorded simultaneously. The acquired scan data is selected for image reconstruction with respect to a pre-defined cardiac phase. Similar to ECG-triggered sequential scanning a certain R-wave delay time defines the start point of data that is used for image reconstruction. ECG-gated spiral scanning has several advantages over ECG- triggered sequential scanning. The continuous acquisition allows for reconstruction of overlapping slices. Due to the retrospective analysis of the ECG, the technique is less sensitive to arrhythmia.

BOTH METHODS REQUIRE ECG MONITORING DIASTOLIC PHASE

SCANNING DURING RR INTERVAL

Retrospective ECG-Gating

CARDIAC CT PROCEDURES CARDIAC ANGIOGRAM CALCIUM SCORING

CARDIAC ANGIOGRAM PERFORMED WITH CONTRAST INJECTION 4-5 cc/sec 150 cc total volume

CALCIUM SCORING NO IV CONTRAST USED

CARDIAC ANGIOGRAM

CALCIUM SCORING

3-D VISUALIZATION TOOLS IN CTA MPR MIP SSD VR CINE

CARDIAC ANGIOGRAM

CTA - MPR PLANE?

MPR PLANE?

MIP - CTA

SSD -CTA

VR - CTA

CINE CTA

MPR SIMPLE FAST ANY PLANE VISUALIZATION LESS USEFUL IN COMPLEX VESSEL VISUALIZATION

SSD FAST LITTLE EDITING LITTLE AXIAL DATA USAGE CONTOUR, RELATIONSHIP OF VESSELS ARTIFACT GENERATION INACCURATE

MIP CALCIFICATION DETECTION THROMBUS DETECTION AILIASING ARTIFACT EDITING REQUIRED

VR ACCURATE ALL DATA USED GOOD STENOSIS DETECTION COMPLEX COMPUTER PROCESSING (PAST)

STEREOSCOPIC VIEWING

Text Book David Sutton’s Radiology Clark’s Radiographic positioning and techniques

Assignment Two students will be selected for assignment.

Question Define Care bolus technique?

Thank You