Left ventricular wall thickness measurements by magnetic resonance: a validation study

Area of Science:

• Cardiovascular Imaging
• Medical Physics
• Diagnostic Radiology

Background:

• Accurate measurement of left ventricular (LV) dimensions is crucial for diagnosing and managing cardiac conditions, particularly coronary artery disease.
• Magnetic resonance (MR) imaging is a non-invasive technique with potential for detailed cardiac assessment.
• Comparison with established methods like digital subtraction angiography (DSA) and echocardiography (Echo) is necessary to validate MR findings.

Purpose of the Study:

• To evaluate the accuracy and precision of magnetic resonance (MR) imaging in determining left ventricular (LV) wall thickness and chamber dimensions.
• To compare MR measurements with those obtained from digital subtraction angiography (DSA) and M-mode echocardiography (Echo).
• To assess the intraobserver and interobserver variability of MR measurements for LV wall thickness.

Main Methods:

• Left ventricular (LV) wall thickness and chamber dimensions were measured using MR in 15 patients (7 controls, 8 with coronary artery disease).
• Measurements were taken in the short axis view perpendicular to the LV long axis at end-diastole (ed) and end-systole (es).
• MR data were compared with simultaneous digital subtraction angiography (DSA) and M-mode echocardiography (Echo) findings.

Main Results:

• MR significantly overestimated LV end-diastolic (34%) and end-systolic (37%) wall thickness compared to DSA.
• MR significantly underestimated LV end-diastolic (25%) and end-systolic (30%) chamber diameter compared to DSA.
• Fractional shortening showed no significant difference across MR, DSA, and Echo. Intraobserver and interobserver variability for MR wall thickness determination was excellent (r=0.99) and good (r=0.90), respectively.

Conclusions:

• Left ventricular (LV) wall thickness and chamber diameter can be assessed by MR with good precision but only satisfactory accuracy.
• MR measurements of LV wall thickness are significantly overestimated, likely due to signals from static blood.
• Despite accuracy limitations, MR demonstrates high reproducibility for LV wall thickness measurements, making it valuable for serial assessments.