Comparison between High-Resolution CT and MRI Using a Very Short Echo Time in Patients with Cystic Fibrosis with Extra Focus on Mosaic Attenuation

Abstract

Background: It would be beneficial to establish pulmonary MRI as a complementary approach to CT for direct visualization of mosaic perfusion, bullae, and emphysema in patients with cystic fibrosis. Objectives: The purpose of this study was to compare both modalities, CT and MRI, using the Helbich-Bhalla score with a special focus on reliable detection of a mosaic pattern. Methods: Out of 51 patients examined by MRI on a 1.5-Tesla system during a period of 2 years, 19 patients were scheduled for additional low-dose CT in a clinical context. The MRI protocol comprised a gradient echo (GRE) sequence with a very short echo time (TE = 0.8 ms) in inspiration and expiration, a 3-D GRE sequence in breath hold, and a fast spin echo sequence with respiration and ECG triggering. MDCT was carried out in inspiration and adapted to body weight using 100 or 120 kV, 30-60 mA, 1- and 3-mm slice thicknesses, as well as low and high kernels. Additionally incremental slices in 3 positions were recorded in expiration for distinct detection of air trapping. CT and MRI analyses were performed by two radiologic readers in consensus unaware of the clinical parameters. The Helbich-Bhalla score of both examinations was correlated. Mean difference and accordance were assessed in each category. Results: There was a strong correlation between CT and MRI (R = 0.87, p < 0.01). The mean Helbich-Bhalla score for CT was 12.2 (range 1-18) and for MRI it was 11.7 (range 2-19). The mean difference was 0.5 points. Besides this strong correlation for findings (bronchiectasis, mucus plugging, peribronchial thickening, and consolidation) with a prolonged T2 TE in MRI, we could also state a qualitative agreement of 95-100% in the categories with short T2 and low signal intensity in MRI as emphysema, bullae, and mosaic perfusion. Conclusions: These results suggest that in our patient group none of the relevant findings were missed by MR imaging and reading.

Pathogenesis, imaging and clinical characteristics of CF and non-CF bronchiectasis

“…MRI has no side effects by radiation enabling long-term surveillance of lung damage. The overall diagnostic performance by scores evaluation of MRI in direct comparison to CT is good to excellent [144][145][146] (Fig. 4).…”

“…4). Moreover, apart from polarized 3+ Helium imaging, functional imaging can be easily implemented using perfusion or ventilation weighted standard proton MRI that assesses small airway disease [146][147][148][149] (Fig. 5).…”

Free‐breathing pediatric chest MRI: Performance of self‐navigated golden‐angle ordered conical ultrashort echo time acquisition

“…Recently, ultrashort echo time (UTE) MRI with 3D radial k ‐space trajectories has shown promise in overcoming these obstacles. However, experience with 3D radial UTE chest MR is limited to animal models and small human studies, mostly in adults . Moreover, 3D radial acquisitions suffer from inherent inefficiencies in fully populating k ‐space, leading to trade‐offs between longer scan times and data undersampling with lesser resolution …”

“…However, experience with 3D radial UTE chest MR is limited to animal models and small human studies, mostly in adults. [15][16][17][18][19][20][21][22][23] Moreover, 3D radial acquisitions suffer from inherent inefficiencies in fully populating k-space, leading to trade-offs between longer scan times and data undersampling with lesser resolution. 24 UTE imaging utilizing conical k-space sampling permits greater scan efficiency than do radial acquisitions.…”

Computed tomography dose optimisation in cystic fibrosis: A review

“…Although CT is considered the gold standard for as sessing CF patients, there may be a role for use of complementary imaging modalities such as pulmonary magnetic resonance imaging (MRI) [32] . MRI is less sensitive for detection of small airways disease (SAD) but is superior for assessing functional change such as changes in pulmonary perfusion [33,34] .…”