Towards quantitative perfusion MRI of the lung in COPD: The problem of short-term repeatability

Abstract

Purpose4D perfusion magnetic resonance imaging (MRI) with intravenous injection of contrast agent allows for a radiation-free assessment of regional lung function. It is therefore a valuable method to monitor response to treatment in patients with chronic obstructive pulmonary disease (COPD). This study was designed to evaluate its potential for monitoring short-term response to hyperoxia in COPD patients.Materials and methods19 prospectively enrolled COPD patients (median age 66y) underwent paired dynamic contrast-enhanced 4D perfusion MRI within 35min, first breathing 100% oxygen (injection 1, O2) and then room air (injection 2, RA), which was repeated on two consecutive days (day 1 and 2). Post-processing software was employed to calculate mean transit time (MTT), pulmonary blood volume (PBV) and pulmonary blood flow (PBF), based on the indicator dilution theory, for the automatically segmented whole lung and 12 regions of equal volume.ResultsComparing O2 with RA conditions, PBF and PBV were found to be significantly lower at O2, consistently on both days (p<10–8). Comparing day 2 to day 1, MTT was shorter by 0.59±0.63 s (p<10–8), PBF was higher by 22±80 ml/min/100ml (p<3·10–4), and PBV tended to be lower by 0.2±7.2 ml/100ml (p = 0.159) at both, RA and O2, conditions.ConclusionThe second injection (RA) yielded higher PBF and PBV, which apparently contradicts the established hypothesis that hyperoxia increases lung perfusion. Quantification of 4D perfusion MRI by current software approaches may thus be limited by residual circulating contrast agent in the short-term and even the next day.

Echo Time‐Dependence of Observed Lung T1 in Patients With Cystic Fibrosis and Correlation With Clinical Metrics

“…This may be advantageous both in patients where contrast agent injection is inadvisable and for repeat measurements, which may also be distorted by residual contrast agent at short time intervals. 39 T 1 (TE) at UTE showed a moderate inverse correlation with age, which decreases toward the longest TE. During growth, alveolar size increases, whereas the increase in numbers of alveoli slows down during early childhood, which results in a subsequent relative increase of air per lung voxel.…”

“…Notably, while this implies T 1 (TE) includes perfusion information, measuring it does not require a contrast agent. This may be advantageous both in patients where contrast agent injection is inadvisable and for repeat measurements, which may also be distorted by residual contrast agent at short time intervals 39 …”

Dynamic Chest X-Ray Using a Flat-Panel Detector System: Technique and Applications

“…In recent clinical practice, scintigraphy has been shown to play an essential role in these evaluations ( 3 4 5 ). CT and MRI are also utilized in lung functional imaging ( 6 7 8 9 10 11 ). In addition, attempts have been made to use X-ray-based techniques, including fluoroscopy and dynamic X-ray (DXR), for cardiopulmonary functional imaging ( 1 2 12 ).…”

Quantification of pulmonary perfusion in idiopathic pulmonary fibrosis with first pass dynamic contrast-enhanced perfusion MRI

“…From a DCE methodological perspective, ongoing work with full quantitative perfusion analysis is being pursued in order to generate associated maps of regional blood flow and blood volume using T1 mapping and arterial input function deconvolution. [37][38][39] Consideration should also be given to the role of anatomical positioning on perfusion. While TL CO is typically measured in the sitting position, MRI is performed supine.…”

“…From a DCE methodological perspective, ongoing work with full quantitative perfusion analysis is being pursued in order to generate associated maps of regional blood flow and blood volume using T1 mapping and arterial input function deconvolution. 37–39 …”