75557

Cardiac magnetic resonance imaging (MRI) for morphology and function without contrast material

Cardiac magnetic resonance imaging (CMR) or Cardiac MRI, identified by CPT code 75557, is a highly specialized, non-invasive diagnostic imaging modality used to evaluate the heart's anatomical structure (morphology) and physiological performance (function). Unlike other cardiac imaging techniques such as echocardiography or computed tomography, CMR provides superior soft-tissue contrast and high-resolution spatial data without the use of ionizing radiation. This specific code, 75557, represents a CMR study performed without the administration of intravenous gadolinium-based contrast agents. The procedure focuses on capturing detailed images of the cardiac chambers, myocardium, pericardium, and the origins of the great vessels. Morphological evaluation includes assessing cardiac chamber size, myocardial thickness, and the presence of structural abnormalities such as masses or congenital defects. Functional assessment involves "cine" imaging, where continuous loops of images are captured throughout the cardiac cycle to calculate the ejection fraction, stroke volume, end-diastolic and end-systolic volumes, and to evaluate regional wall motion. This is crucial for diagnosing various types of cardiomyopathy, such as dilated or hypertrophic forms. Additionally, CMR is considered a gold standard for quantifying ventricular volumes and mass. The absence of contrast material in this procedure code makes it suitable for patients with severe renal impairment (low GFR) who are at risk for Nephrogenic Systemic Fibrosis (NSF) or those requiring basic structural follow-up where tissue characterization via late gadolinium enhancement is not strictly necessary for the immediate clinical question. The study requires complex post-processing and a high level of expertise in cardiovascular radiology or cardiology to interpret the multiplanar reconstructions and functional data sets accurately.

Clinical Indications

  • Evaluation of cardiomyopathies (dilated, hypertrophic, restrictive)
  • Assessment of ventricular function and volume
  • Monitoring of congenital heart disease
  • Evaluation of cardiac masses or tumors
  • Assessment of pericardial disease and thickness
  • Quantification of valvular heart disease and regurgitant fractions
  • Evaluation of aortic or pulmonary vessel anatomy
  • Initial diagnostic workup for heart failure of unknown etiology

Procedure Steps

  1. Perform comprehensive patient safety screening for MRI-incompatible metallic implants or devices
  2. Place ECG leads on the patient's chest for cardiac gating to synchronize imaging with the heart cycle
  3. Position the patient in the MRI bore, typically in a supine position with a dedicated cardiac coil
  4. Obtain multi-slice scout images in various planes to localize the heart within the thorax
  5. Execute steady-state free precession (SSFP) cine sequences to capture cardiac motion for functional analysis
  6. Perform black-blood sequences (T1 and T2 weighted) to evaluate cardiac morphology and tissue structure
  7. Provide breath-holding instructions to the patient to eliminate respiratory motion artifacts during data acquisition
  8. Perform post-processing on a dedicated workstation to calculate ejection fraction, stroke volume, and myocardial mass

Coding Guidelines

  • Report 75557 only for cardiac MRI studies performed without contrast material
  • Do not report 75557 in conjunction with codes 75559, 75561, or 75563 for the same imaging session
  • If flow quantification is performed, it may be reported separately using add-on code 75565
  • For the professional component only, append modifier 26
  • For the technical component only, append modifier TC
  • Contrast administration during the same session requires a shift in coding to 75561
  • Pharmacological stress testing performed during MRI should be reported with 75559 or 75563

Associated ICD-10 Codes