A semiquantitative MRI-Score can predict loss of lung function in patients with cystic fibrosis: Preliminary results

Structural changes in lung morphology detected by MRI after modulating therapy with elexacaftor/tezacaftor/ivacaftor in adolescent and adult patients with cystic fibrosis

INTRODUCTION

Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) improves CFTR function in cystic fibrosis (CF) patients homozygous or heterozygous for F508del mutation. The aim of the study was to evaluate the response to ELX/TEZ/IVA treatment both clinically and morphologically in terms of bronchiectasis, bronchial wall thickening, mucus plugging, abscess and consolidations.

METHODS

We retrospectively collected data from CF patients followed at Parma CF Centre (Italy) treated by ELX/TEZ/IVA between March and November 2021. Post-treatment changes in respiratory function, quality of life, sweat chloride concentration, body mass index, pulmonary exacerbations and lung structure by chest magnetic resonance imaging (MRI) were assessed. T2-and T1-weighted sequences were acquired with a 20 min-long scanning protocol on a 1.5T MRI scanner (Philips Ingenia) without administration of intravenous contrast media.

RESULTS

19 patients (32.5 ± 10.2 years) were included in the study. After 6 months of treatment with ELX/TEZ/IVA, MRI showed significant improvements in the morphological score (p < 0.001), with a reduction in bronchial wall thickening (p < 0.001) and mucus plugging (p 0.01). Respiratory function showed significant improvement in predicted FEV₁% (58.5 ± 17.5 vs 71.4 ± 20.1, p < 0.001), FVC% (79.0 ± 11.1 vs 88.3 ± 14.4, p < 0.001), FEV₁/FVC (0.61 ± 0.16 vs 0.67 ± 0.15, <0.001) and LCI_2.5% (17.8 ± 4.3 vs 15.8 ± 4.1 p < 0.005). Significant improvement was found in body mass index (20.6 ± 2.7 vs 21.9 ± 2.4, p < 0.001), pulmonary exacerbations (2.3 ± 1.3 vs 1.4 ± 1.3 p 0.018) and sweat chloride concentration (96.5 ± 36.6 vs 41.1 ± 16.9, p < 0.001).

CONCLUSIONS

Our study confirms the efficacy of ELX/TEZ/IVA in CF patients not only from a clinical point of view but also in terms of morphological changes of the lungs.

Chest magnetic resonance imaging in cystic fibrosis: technique and clinical benefits

Cystic fibrosis (CF) is one of the most common inherited and life-shortening pulmonary diseases in the Caucasian population. With the widespread introduction of newborn screening and the development of modulator therapy, tremendous advances have been made in recent years both in diagnosis and therapy. Since paediatric CF patients tend to be younger and have lower morbidity, the type of imaging modality that should be used to monitor the disease is often debated. Computed tomography (CT) is sensitive to many pulmonary pathologies, but radiation exposure limits its use, especially in children and adolescents. Conventional pulmonary magnetic resonance imaging (MRI) is a valid alternative to CT and, in most cases, provides sufficient information to guide treatment. Given the expected widespread availability of sequences with ultra-short echo times, there will be even fewer reasons to perform CT for follow-up of patients with CF. This review aims to provide an overview of the process and results of monitoring CF with MRI, particularly for centres not specialising in the disease.

State-of-the-art review of lung imaging in cystic fibrosis with recommendations for pulmonologists and radiologists from the "iMAging managEment of cySTic fibROsis" (MAESTRO) consortium

OBJECTIVE

Imaging represents an important noninvasive means to assess cystic fibrosis (CF) lung disease, which remains the main cause of morbidity and mortality in CF patients. While the development of new imaging techniques has revolutionised clinical practice, advances have posed diagnostic and monitoring challenges. The authors aim to summarise these challenges and make evidence-based recommendations regarding imaging assessment for both clinicians and radiologists.

STUDY DESIGN

A committee of 21 experts in CF from the 10 largest specialist centres in Italy was convened, including a radiologist and a pulmonologist from each centre, with the overall aim of developing clear and actionable recommendations for lung imaging in CF. An a priori threshold of at least 80% of the votes was required for acceptance of each statement of recommendation.

RESULTS

After a systematic review of the relevant literature, the committee convened to evaluate 167 articles. Following five RAND conferences, consensus statements were developed by an executive subcommittee. The entire consensus committee voted and approved 28 main statements.

CONCLUSIONS

There is a need for international guidelines regarding the appropriate timing and selection of imaging modality for patients with CF lung disease; timing and selection depends upon the clinical scenario, the patient's age, lung function and type of treatment. Despite its ubiquity, the use of the chest radiograph remains controversial. Both computed tomography and magnetic resonance imaging should be routinely used to monitor CF lung disease. Future studies should focus on imaging protocol harmonisation both for computed tomography and for magnetic resonance imaging. The introduction of artificial intelligence imaging analysis may further revolutionise clinical practice by providing fast and reliable quantitative outcomes to assess disease status. To date, there is no evidence supporting the use of lung ultrasound to monitor CF lung disease.

1.5 vs 3 Tesla Magnetic Resonance Imaging: A Review of Favorite Clinical Applications for Both Field Strengths-Part 2

ABSTRACT

The second part of this review deals with experiences in neuroradiological and pediatric examinations using modern magnetic resonance imaging systems with 1.5 T and 3 T, with special attention paid to experiences in pediatric cardiac imaging. In addition, whole-body examinations, which are widely used for diagnostic purposes in systemic diseases, are compared with respect to the image quality obtained in different body parts at both field strengths. A systematic overview of the technical differences at 1.5 T and 3 T has been presented in part 1 of this review, as well as several organ-based magnetic resonance imaging applications including musculoskeletal imaging, abdominal imaging, and prostate diagnostics.

Ultrashort echo time MRI of the lung in children and adolescents: comparison with non-enhanced computed tomography and standard post-contrast T1w MRI sequences

Objectives

To compare the diagnostic value of ultrashort echo time (UTE) magnetic resonance imaging (MRI) for the lung versus the gold standard computed tomography (CT) and two T1-weighted MRI sequences in children.

Methods

Twenty-three patients with proven oncologic disease (14 male, 9 female; mean age 9.0 + / − 5.4 years) received 35 low-dose CT and MRI examinations of the lung. The MRI protocol (1.5-T) included the following post-contrast sequences: two-dimensional (2D) incoherent gradient echo (GRE; acquisition with breath-hold), 3D volume interpolated GRE (breath-hold), and 3D high-resolution radial UTE sequences (performed during free-breathing). Images were evaluated by considering image quality as well as distinct diagnosis of pulmonary nodules and parenchymal areal opacities with consideration of sizes and characterisations.

Results

The UTE technique showed significantly higher overall image quality, better sharpness, and fewer artefacts than both other sequences. On CT, 110 pulmonary nodules with a mean diameter of 4.9 + / − 2.9 mm were detected. UTE imaging resulted in a significantly higher detection rate compared to both other sequences (p < 0.01): 76.4% (84 of 110 nodules) for UTE versus 60.9% (67 of 110) for incoherent GRE and 62.7% (69 of 110) for volume interpolated GRE sequences. The detection of parenchymal areal opacities by the UTE technique was also significantly higher with a rate of 93.3% (42 of 45 opacities) versus 77.8% (35 of 45) for 2D GRE and 80.0% (36 of 45) for 3D GRE sequences (p < 0.05).

Conclusion

The UTE technique for lung MRI is favourable in children with generally high diagnostic performance compared to standard T1-weighted sequences as well as CT.

Key Points

• Due to the possible acquisition during free-breathing of the patients, the UTE MRI sequence for the lung is favourable in children.

• The UTE technique reaches higher overall image quality, better sharpness, and lower artefacts, but not higher contrast compared to standard post-contrast T1-weighted sequences.

• In comparison to the gold standard chest CT, the detection rate of small pulmonary nodules small nodules ≤ 4 mm and subtle parenchymal areal opacities is higher with the UTE imaging than standard T1-weighted sequences.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00330-021-08236-7.

Effectiveness of Chest CT in Children: CT Findings in Relation to the Clinical Question

PURPOSE

 To estimate the effectiveness and efficiency of chest CT in children based on the suspected diagnosis in relation to the number of positive, negative, and inconclusive CT results.

MATERIALS AND METHODS

 In this monocentric retrospective study at a university hospital with a division of pediatric radiology, 2019 chest CT examinations (973 patients; median age: 10.5 years; range: 2 days to 17.9 years) were analyzed with regards to clinical data, including the referring department, primary questions or suspected diagnosis, and CT findings. It was identified if the clinical question was answered, whether the suspected diagnosis was confirmed or ruled out, and if additional findings (clinically significant or minor) were detected.

RESULTS

 The largest clinical subgroup was the hematooncological subgroup (n = 987), with frequent questions for inflammation/pneumonia (66 % in this subgroup). Overall, CT provided conclusive results in 97.6 % of all scans. In 1380 scans (70 %), the suspected diagnosis was confirmed. In 406/2019 cases (20 %), the CT scan was negative also in terms of an additional finding. In 8 of 9 clinical categories, the proportion of positive results was over 50 %. There were predominantly negative results (110/179; 61 %) in pre-stem cell transplant evaluation. In the subgroup of trauma management, 81/144 exams (57 %) showed positive results, including combined injuries (n = 23). 222/396 (56 %) of all additional findings were estimated to be clinically significant.

CONCLUSION

 In a specialized center, the effectiveness of pediatric chest CT was excellent when counting the conclusive results. However, to improve efficiency, the clinical evaluation before imaging appears crucial to prevent unnecessary CT examinations.

KEY POINTS

  · Pediatric chest CT in specialized centers has a high diagnostic value.. · CT identifies relevant changes besides the working hypothesis in clinically complex situations.. · Pre-CT clinical evaluation is crucial, especially in the context of suspected pneumonia..

CITATION FORMAT

· Esser M, Tsiflikas I, Kraus MS et al. Effectiveness of Chest CT in Children: CT Findings in Relation to the Clinical Question. Fortschr Röntgenstr 2021; DOI: 10.1055/a-1586-3023.

Sensitive structural and functional measurements and 1-year pulmonary outcomes in pediatric cystic fibrosis

BACKGROUND

Two functional measurements (multiple breath washout [MBW] and hyperpolarized ¹²⁹Xe ventilation magnetic resonance imaging [¹²⁹Xe MRI]) have been shown to be more sensitive to cystic fibrosis (CF) lung obstruction than traditional spirometry. However, functional techniques may be sensitive to different underlying structural abnormalities. The purpose of this study was to determine relationships between these functional markers, their pathophysiology, and 1-year clinical outcomes.

METHODS

Spirometry, MBW, ¹²⁹Xe MRI, and ultrashort echo-time (UTE) MRI were obtained in a same-day assessment of 27 pediatric CF patients (ages 11.5±5.0) who had not begun CFTR modulator therapies. UTE MRI was scored for structural abnormalities and functional metrics obtained via spirometry, MBW and ¹²⁹Xe MRI. 1-year outcomes (ΔFEV₁ and pulmonary exacerbations), during which ≈50% initiated modulator therapy, were obtained from the electronic medical record.

RESULTS

MBW, ¹²⁹Xe MRI, and UTE MRI detected clinically significant disease in more subjects (>78%) compared to spirometry (<30%). UTE MRI suggests increased odds of bronchial changes when mucus plugging is present in the same lobe. MBW and ¹²⁹Xe MRI correlated best with mucus plugging, while spirometry correlated best with consolidations. Bronchial abnormalities were associated with future pulmonary exacerbations.

CONCLUSIONS

MBW, ¹²⁹Xe MRI, and UTE MRI are more sensitive for detection of pediatric CF lung disease when compared to spirometry. MBW and ¹²⁹Xe MRI correlated with structural abnormalities which occur in early CF disease, suggesting MBW and ¹²⁹Xe MRI are valuable tools in mild CF lung disease that can guide clinical decision making.

[Magnetic resonance imaging of the lungs in cystic fibrosis]

CLINICAL ISSUE

Disease severity and mortality in patients with cystic fibrosis (CF) is mainly determined by (progressive) pulmonary lung disease. Early diagnosis and therapy are important and of prognostic value to conserve lung function.

STANDARD RADIOLOGICAL METHODS

Primary imaging techniques for lung imaging are x‑ray and computed tomography (CT) to monitor disease severity and regional distribution.

METHODICAL INNOVATIONS

Radiation-free imaging techniques such as magnetic resonance imaging (MRI) have gained interest over the last decade in order to prevent radiation damage.

PERFORMANCE

The main findings of CF lung disease are airway wall thickening, bronchiectasis, and mucus plugging, which are found in up to 60% of preschool age children. Pleural abnormalities and consolidations are often associated with pulmonary exacerbation. Young CF patients often show a mosaic pattern as functional changes and also perfusion defects can be seen from birth in 50% of CF patients by contrast-enhanced perfusion imaging, and in up to 90% of adult patients, with varying degrees of severity. Dilated bronchial arteries indicate an increased risk for hemoptysis.

ACHIEVEMENTS

Proton MRI is the sole imaging technique that can show structural and functional lung changes in one examination. Structured assessment using a scoring system helps to systematically grade the extent and severity of all CF-associated changes.

CONCLUSIONS

Lung MRI for cystic fibrosis has been recently established as a clinical standard examination and is routinely performed at experienced centers. More recently, it has also been used as an endpoint within the framework of clinical studies.

Will Airway Gene Therapy for Cystic Fibrosis Improve Lung Function? New Imaging Technologies Can Help Us Find Out

The promise of genetic therapies has turned into reality in recent years, with new first-line treatments for fatal diseases now available to patients. The development and testing of genetic therapies for respiratory diseases such as cystic fibrosis (CF) has also progressed. The addition of gene editing to the genetic agent toolbox, and its early success in other organ systems, suggests we will see rapid expansion of gene correction options for CF in the future. Although substantial progress has been made in creating techniques and genetic agents that can be highly effective for CF correction in vitro, physiologically relevant functional in vivo changes have been largely prevented by poor delivery efficiency within the lungs. Somewhat hidden from view, however, is the absence of reliable, accurate, detailed, and noninvasive outcome measures that can detect subtle disease and treatment effects in the lungs of humans or animal models. The ability to measure the fundamental function of the lung-ventilation, the effective transport of air throughout the lung-has been constrained by the available measurement technologies. Without sensitive measurement methods, it is difficult to quantify the effectiveness of genetic therapies for CF. The mainstays of lung health assessment are spirometry, which cannot provide adequate disease localization and is not sensitive enough to detect small early changes in disease; and computed tomography, which provides structural rather than functional information. Magnetic resonance imaging using hyperpolarized gases is increasingly useful for lung ventilation assessment, and it removes the radiation risk that accompanies X-ray methods. A new lung imaging technique, X-ray velocimetry, can now offer highly detailed regional lung ventilation information well suited to the diagnosis, treatment, and monitoring needs of CF lung disease, particularly after the application of genetic therapies. In this review, we discuss the options now available for imaging-based lung function measurement in the generation and use of genetic and other therapies for treating CF lung disease.

Imaging of Airway Obstruction in Children

Various imaging techniques may be used to diagnose airway obstruction in children. Digital radiography, computed tomography and magnetic resonance imaging are the most important modalities, but the choice of technique will depend on the level and nature of suspected obstruction, as well as patient-specific factors such as age and ability to cooperate. This review examines the forms of airway obstruction that are commonly encountered in childhood.

Volumetric dynamic oxygen-enhanced MRI (OE-MRI): comparison with CT Brody score and lung function in cystic fibrosis patients

OBJECTIVES

To demonstrate, in patients with cystic fibrosis (CF), the correlation between three-dimensional dynamic oxygen-enhanced magnetic resonance imaging (OE-MRI) measurements and computed tomography Brody score (CF-CT) and lung function testing (LFT).

METHODS

Twenty-one patients (median age, 25 years; female, n = 8) with a range of CF lung disease and five healthy volunteers (median age, 31 years; female, n = 2) underwent OE-MRI performed on a 1.5-T MRI scanner. Coronal volumes were acquired while patients alternately breathed room air and 100% oxygen. Pre-oxygen T₁ was measured. Dynamic series of T₁-weighted volumes were then obtained while breathing oxygen. T₁-parameter maps were generated and the following OE-MRI parameters were measured: oxygen uptake (ΔPO_2max), wash-in time and wash-out time. High-resolution CT and LFT were performed. The relationship between CF-CT, LFT and OE-MRI parameters were evaluated using Pearson correlation for the whole lung and regionally.

RESULTS

Mean CF-CT was 24.1±17.1. Mean ΔPO_2max and mean wash-in as well as skewness of wash-out showed significant correlation with CF-CT (ΔPO_2max: r = -0.741, p < 0.001; mean wash-in: r = 0.501, p = 0.017; skewness of wash-out: r = 0.597, p = 0.001). There was significant correlation for the whole lung and regionally between LFT parameters and OE-MR (ΔPO_2max: r = 0.718, p < 0.001; wash-in: r = -0.576, p = 0.003; wash-out skewness: r = -0.552, p = 0.004).

CONCLUSIONS

Functional lung imaging using OE-MRI has the capability to assess the severity of CF lung disease and shows a significant correlation with LFT and CF-CT.

KEY POINTS

• Oxygen-enhanced MRI might play a future role in evaluation and follow-up of cystic fibrosis. • Heterogeneity of parameter maps reflects localised functional impairment in cystic fibrosis. • Avoidance of cumulative radiation burden in CF is feasible using OE-MRI.