Imaging human lung perfusion with contrast media: A meta-analysis

Area of Science:

• Radiology and Imaging
• Cardiovascular and Pulmonary Physiology
• Medical Physics

Background:

• Establishing reliable reference values for human lung perfusion parameters is crucial for diagnosing and monitoring pulmonary diseases.
• Perfusion MRI and CT are advanced imaging techniques that allow for quantitative assessment of pulmonary blood flow (PBF), pulmonary blood volume (PBV), and mean transit time (MTT).

Approach:

• A systematic literature search was conducted on PubMed to identify studies quantifying PBF, PBV, and MTT in the human lung using perfusion MRI or CT.
• Data from studies employing the 'indicator dilution theory' were numerically analyzed to calculate weighted means, standard deviations, and coefficients of variance for healthy volunteers.
• Methods for signal to concentration conversion, breath holding, and pre-bolus administration were documented.

Key Points:

• Reference values for healthy volunteers (HV) were established: PBV (wM: 13.97 ml/100ml), MTT (wM: 5.91 s), and PBF (wM: 246.26 ml/100ml/min).
• Signal normalization influenced PBV and PBF, with higher values observed when normalized.
• No significant differences in PBV and PBF were found based on breathing states or the presence/absence of a pre-bolus contrast agent.

Conclusions:

• Reliable reference values for pulmonary blood flow, blood volume, and mean transit time in healthy individuals have been successfully pooled from existing literature.
• The current body of literature is insufficient to derive robust reference values for these perfusion parameters in diseased lung conditions.