Assessment of bolus injection protocol with appropriate concentration for quantitative assessment of pulmonary perfusion by dynamic contrast-enhanced MR imaging

Purpose: To determine the appropriate concentration for quantitative assessment of dynamic contrast-enhanced pulmonary MR imaging. Materials and Methods: A total of 40 consecutive patients with small bronchioalveolar carcinoma underwent perfusion single-photon emission tomography (SPECT) and three-dimensional (3D) dynamic MR imaging with a 3D radiofrequency spoiled gradient-echo sequence. In each patient, 5 mL of contrast media with 0.1, 0.3, and 0.5 mmol/mL were administered at a rate of 5 mL/second. All patients were divided into two groups (<70 kg and ≥70 kg) for assessment of appropriate concentration to quantitatively assess regional perfusion parameter in routine clinical practice. Pulmonary blood flow (PBF) in each protocol was calculated from a signal intensity (SI)-time course curve. Differences and limits of agreement of PBF between dynamic MR imaging (PBF_MR) using three different concentrations and perfusion SPECT (PBF_SPEcT) were statistically compared in both patient groups. Results: PBF_MR using 0.3 mmol/mL in the <70-kg group and 0.5 mmol/mL in the ≥70-kg group showed no significant difference compared with PBF_SPECT (P > 0.05). Limits of agreements in 0.3 mmol/mL in the <70-kg group and 0.5 mmol/mL in the ≥70-kg group were smaller than those of the other concentrations and small enough for clinical purposes. Conclusion: Appropriate concentrations provide accurate and reproducible assessments of regional pulmonary perfusion parameters on 3D dynamic MR perfusion imaging. We suggest using 5 mL of contrast media with 0.3 mmol/mL for patients weighing less than 70 kg and 0.5 mmol/mL for patients weighing 70 kg or more.