Key result
MR velocity mapping quantifies QP/QS with significantly lower interobserver variability than radionuclide angiography.
Why the study?
The agreement between MR velocity mapping and first-pass radionuclide angiography to quantify pulmonary-to-systemic blood flow ratio in left-to-right cardiac shunts was investigated.
Does MR velocity mapping provide accurate and precise measurements of pulmonary-to-systemic blood flow ratio compared to radionuclide angiography in patients with left-to-right cardiac shunts?
Cross-Sectional (n=36)
Does MR velocity mapping provide accurate and precise measurements of pulmonary-to-systemic blood flow ratio compared to radionuclide angiography in patients with left-to-right cardiac shunts?
MR velocity mapping is an accurate and precise method for measuring shunt size in patients with left-to-right cardiac shunts, demonstrating lower interobserver variability than radionuclide angiography.
MR velocity mapping shows lower variability than radionuclide angiography for QP/QS; leaves open whether it should supplant other methods in clinical shunt evaluation.
PURPOSE: To investigate the agreement between two noninvasive methods, magnetic resonance (MR) velocity mapping and first-pass radionuclide angiography, to quantify the pulmonary-to-systemic blood flow ratio (QP/QS) in adults, adolescents, and children with left-to-right cardiac shunts. MATERIALS AND METHODS: The accuracy and precision of MR velocity mapping were studied in 12 control subjects (six men, six women) and in a phantom. MR velocity mapping and radionuclide angiography were performed on the same day in 24 patients (16 adults, two adolescents, six children; five male patients, 19 female patients). RESULTS: The mean error in QP/QS at MR velocity mapping in phantom experiments was -1% +/- 1 (mean +/- SD). In control subjects, QP/QS at MR velocity mapping was 1.03 +/- 0.03, and the cardiac index was 3.1 L/min/m2 +/- 0.2 and 3.2 L/min/m2 +/- 0.3 for women and men, respectively. In patients, QP/QS at radionuclide angiography was 14% +/- 13, higher than at MR velocity mapping. Interobserver variability was four times higher for radionuclide angiography compared with MR velocity mapping, 0% + 16 versus 0% +/- 4 (n = 12). The difference between repeated MR flow measurements in the same vessel was -1% +/- 5 (n = 36). CONCLUSION: The data suggest that MR velocity mapping is accurate and precise for measurements of shunt size over the whole range of possible QP/QS values.
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Arheden et al. (1999) conducted a cross-sectional in Left-to-right cardiac shunts (n=36). MR velocity mapping vs. First-pass radionuclide angiography was evaluated on Pulmonary-to-systemic blood flow ratio (QP/QS). MR velocity mapping accurately measured shunt size (QP/QS) with lower interobserver variability (0% ± 4) compared to radionuclide angiography (0% ± 16).
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