CT — Artere coronare (MCB)

Updated 05/06/24 CTA Coronary Arteries Reviewed 05/14/25 Indications - chest pain, tachycardia, hypotension, shortness of breath, dyspnea, orthopnea, abnormal EKG, abnormal cardiovascular study, coronary atherosclerosis, ischemic cardiomyopathy, coronary artery dissection/aneurysm, coronary artery malformation, anomalous coronary artery origin. Bill under CT Angio Coronary w/ Contrast charge. GENERAL SCAN NOTES Move the patient's arms over his/her head if possible. Remove any metal from the imaging field of view. Topogram - lung apices through diaphragm (obtained during end inspiration). Craniocaudal scan coverage: No CABG history - above carina through apex of left ventricle (obtained during end inspiration). Positive CABG history - lung apices through apex of left ventricle (obtained during end inspiration). Adjust FOV (field of view) on topogram to smallest without cropping anatomy (target FOV 150-220 mm). IV Contrast: Administer 80 mL Omnipaque-350 (<350 lbs) or 100 mL Omnipaque-350 (>350 lbs). Inject at 6 mL/sec followed by 40 mL saline flush, 20-gauge or larger in AC fossa. Bolus track off ascending aorta triggered at 100 HU + 5 secs. EKG Gating MEDICATIONS Heart Rate Control At Home Medications Metoprolol immediate-release 50 mg or diltiazem immediate-release 30 mg One tablet the night before and one tablet the morning of the exam. The prescription for this medication is the responsibility of whomever ordered the CTA. Pre Exam Medications Metoprolol 10 mg IV or diltiazem 0.25 mg/kg (up to 25 mg) IV given 5 mins before CTA portion. Can repeat 5 mg metoprolol every 5 mins as needed. Only given if patient's heart rate >70 bpm and systolic BP >100 mmHg.

CTA Coronary Arteries Contraindications to metoprolol - COPD, asthma, 2nd or 3rd degree heart block, systolic BP <100 mm Hg or allergy to metoprolol. Contraindications to diltiazem - 2nd or 3rd degree heart block (w/o pacemaker), systolic BP < 100 mm Hg or allergy to diltiazem. Vasodilatation Medications Nitroglycerin 0.4 mg tablet given 3-5 mins before CTA portion. Can cause reflex elevated heart rate (which is blocked by metoprolol). Given to all patients regardless of heart rate (unless contraindicated) Contraindications to nitroglycerine - increased intracranial pressure, severe anemia, right-sided myocardial infarction or allergy to nitroglycerin.

CTA Coronary Arteries SIEMENS PARAMETERS & RECONS For Calcium Score scan: Use technical parameters from calcium score protocol. Perform calcium score scan in all patients except: Patients with a history of CABG. Patients who have had calcium score within past 12 months. For CTA Coronary scan: Scan
Care
Scan
Pitch Coll Rot Mode kV mAs Care
Dose kV & Lvl Feed Acq Time Time Go Top 64 spiral 100 54 on on 64 0.31 4.2 64 0.6 0.33 Drive 128 sequential 120 282 on on 34.5 128 0.6 0.285 1.2 Force 192 sequential 120 288 on on 39 152 0.6 0.25 1.0 CALCIUM SCORE IR
Recon
Name of Series Thick Interval Kernel Window Lvl Direction AX SOFT 3.0 1.5 Sa36 mediastinum 3 head/feet CTA CORONARY AX SOFT 3.0 3.0 cardiac 3 head/feet Bv40 AX THINS 0.6 0.3 cardiac 3 Bv36 head/feet AX TRUESTACK 0.6 0.6 Bf44 cardiac 3 head/feet head/feet *AX MULTI 20-80% 0.6 0.3 cardiac 3 Bv36 AX LUNG 3.0 3.0 Bl59 lung 3 head/feet * Ax Multi 20-80% series only applies with retrospective scans.