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.

Blood flow characteristics after aortic valve neocuspidization in paediatric patients: a comparison with the Ross procedure.

AIMS: The aortic valve (AV) neocuspidization (Ozaki procedure) is a novel surgical technique for AV disease that preserves the natural motion and cardiodynamics of the aortic root. In this study, we sought to evaluate, by 4D-flow magnetic resonance imaging, the aortic blood flow characteristics after AV neocuspidization in paediatric patients. METHODS AND RESULTS: Aortic root and ascending aorta haemodynamics were evaluated in a population of patients treated with the Ozaki procedure; results were compared with those of a group of patients operated with the Ross technique. Cardiovascular magnetic resonance studies were performed at 1.5 T using a 4D flow-sensitive sequence acquired with retrospective electrocardiogram-gating and respiratory navigator. Post-processing of 4D-flow analysis was performed to calculate flow eccentricity and wall shear stress. Twenty children were included in this study, 10 after Ozaki and 10 after Ross procedure. Median age at surgery was 10.7 years (range 3.9-16.5 years). No significant differences were observed in wall shear stress values measured at the level of the proximal ascending aorta between the two groups. The analysis of flow patterns showed no clear association between eccentric flow and the procedure performed. The Ozaki group showed just a slightly increased transvalvular maximum velocity. CONCLUSION: Proximal aorta flow dynamics of children treated with the Ozaki and the Ross procedure are comparable. Similarly to the Ross, Ozaki technique restores a physiological laminar flow pattern in the short-term follow-up, with the advantage of not inducing a bivalvular disease, although further studies are warranted to evaluate its long-term results.

The Role of Lung Function Testing in Newborn Infants With Congenital Thoracic Arterial Anomalies.

Introduction: Congenital thoracic arterial anomalies (CTAAs), such as complete or incomplete vascular rings, pulmonary artery sling, and innominate artery compression syndrome, may cause severe tracheomalacia and upper airway obstruction. An obstructive ventilatory pattern at lung function testing (LFT) has been suggested in the presence of CTAA. The severity of obstruction may be evaluated by LFT. Little is known about the use of LFT in newborn infants with CTAA. The aim of our study is to evaluate the role of LFT in CTAA diagnosis. Methods: This is a retrospective study, conducted between February 2016 and July 2020. All CTAA cases for whom LFT was performed preoperatively were considered for inclusion. Tidal volume (Vt), respiratory rate, and the ratio of time to reach the peak tidal expiratory flow over total expiratory time (tPTEF/tE) were assessed and compared to existing normative data. Demographics and CTAA characteristics were also collected. Results: Thirty cases were included. All infants with CTAA showed a significantly reduced Vt and tPTEF/tE, compared to existing normative data suggesting an obstructive pattern. No significant differences were found for LFT between cases with a tracheal obstruction <50% compared to those with tracheal obstruction ≥50%, or between cases with and without symptoms. Sixteen infants (53.3%) had respiratory symptoms related to CTAA. Of these, only two cases had also dysphagia. Conclusion: LFT values were significantly reduced in cases with CTAA before surgery. LFT represents a potential feasible and non-invasive useful tool to guide diagnosis in the suspect of CTAA.

Tracheal trifurcation: new cases and review of the literature.

BACKGROUND: Tracheal trifurcation is an uncommon and often unknown type of anomalous tracheobronchial arborization, characterized by three main bronchi originating at the level of the carina. Diagnosis is important due to its clinical implications. OBJECTIVE: To highlight the anatomical, clinical and diagnostic aspects of tracheal trifurcation by reporting our experience and reviewing the literature. MATERIALS AND METHODS: We retrospectively evaluated pediatric patients referred to our institution from January 2018 to May 2020 with a diagnosis of tracheal trifurcation. All patients underwent chest radiographs, computed tomography (CT) (with/without dynamic airway scanning) and bronchoscopy. Clinical and anatomical data were collected. RESULTS: Three patients with tracheal trifurcation were identified (1 female, median age: 7.6±0.4 months). All had associated anomalies: two had tetralogy of Fallot, one with esophageal atresia/tracheoesophageal fistula and one with an atrioventricular septal defect, and the other had skeletal ciliopathy. Chest radiographs were not diagnostic for tracheal trifurcation. Bronchoscopy could not fully evaluate the trachea and main bronchi in two cases. CT detected tracheal trifurcation in all of the patients and also demonstrated other lung parenchymal and congenital anomalies. Two of the three main bronchi were directed to the right lung in all cases. Ostial stenosis of either the central (two patients) or right upper bronchus (one patient) was present. No signs of tracheobronchomalacia were found. CONCLUSION: Tracheal trifurcation is rare and often associated with additional disorders, such as other tracheobronchial anomalies, cardiovascular defects or esophageal malformations, responsible for clinical manifestations and earlier detection. Bronchoscopy is often used for diagnosis, but is invasive and may be incomplete or inconclusive, while CT allows for a noninvasive and correct diagnosis, while also highlighting additional findings in the thorax.

Dynamic expiratory CT: An effective non-invasive diagnostic exam for fragile children with suspected tracheo-bronchomalacia.

BACKGROUND: Tracheobronchomalacia, defined as variable collapse of the airways, has been recognized as an important cause of respiratory morbidity but still widely underdiagnosed. Bronchoscopy is still considered as the gold standard, but numerous limitations are known, especially for fragile sick children. Moreover, information on parenchymal lung disease cannot be described. There is a real need for a reliable, non-invasive test to help detection of airway and parenchymal malformations in children, specifically when bronchoscopy cannot be performed. METHODS AND RESULTS: 34 paediatric patients underwent cine multidector CT for ongoing respiratory symptoms and were included. All CT images were of good quality and sedation was never needed. Airway disease such as trachea-broncomalacia with/without stenosis was described in 53% with the first being more frequent. Bronchomalacia alone was described in 10 patients and in 4 patients was associated with tracheomalacia. Moreover, CT allowed identification of parenchymal disease in 10 patients. Airways stenosis alone was detected in seven patients. The majority of patients (85%) underwent also bronchoscopy for clinical decision. The agreement between CT and bronchoscopy was explored. The two examinations did not agree only in two cases. CT dynamic showed an excellent sensitivity of 100% (81.47-100 %), a great specificity of 82% (48.22-97.72 %), NPV 100%, and PPV 90% (72-96.9 %). CONCLUSION: Dynamic CT results an effective and highly sensitive diagnostic exam for children with tracheo-bronchomalacia. CT is especially indicated for those small and fragile patients that cannot undergo an invasive investigation. Moreover, CT allows a detailed evaluation both of the airways and the lungs which is useful for the clinical management.

Radiation dose levels in pediatric chest CT: experience in 499 children evaluated with dual-source single-energy CT.

BACKGROUND: The availability of dual-source technology has introduced the possibility of scanning children at lower kVp with a high-pitch mode, combining high-speed data acquisition and high temporal resolution. OBJECTIVE: To establish the radiation dose levels of dual-source, single-energy chest CT examinations in children. MATERIALS AND METHODS: We retrospectively recorded the dose-length product (DLP) of 499 consecutive examinations obtained in children <50 kg, divided into five weight groups: group 1 (<10 kg, n = 129); group 2 (10-20 kg, n = 176); group 3 (20-30 kg, n = 99), group 4 (30-40 kg, n = 58) and group 5 (40-49 kg, n = 37). All CT examinations were performed with high temporal resolution (75 ms), a high-pitch mode and a weight-adapted selection of the milliamperage. RESULTS: CT examinations were obtained at 80 kVp with a milliamperage ranging between 40 mAs and 90 mAs, and a pitch of 2.0 (n = 162; 32.5%) or 3.0 (n = 337; 67.5%). The mean duration of data acquisition was 522.8 ± 192.0 ms (interquartile range 390 to 610; median 490). In the study population, the mean CT dose index volume (CTDIvol32) was 0.83 mGy (standard deviation [SD] 0.20 mGy; interquartile range 0.72 to 0.94; median 0.78); the mean DLP32 was 21.4 mGy.cm (SD 9.1 mGy.cm; interquartile range 15 to 25; median 19.0); and the mean size-specific dose estimate (SSDE) was 1.7 mGy (SD 0.4 mGy; interquartile range 1.5 to 1.9; median 1.7). The DLP32, CTDIvol32 and SSDE were found to be statistically significant in the five weight categories (P < 0.0001). CONCLUSION: This study establishes the radiation dose levels for dual-source, single-kVp chest CT from a single center. In the five weight categories, the median values varied 15-37 mGy.cm for the DLP32, 0.78-1.25 mGy for the CTDIvol32 and 1.6-2.1 mGy for the SSDE.

Estimated risk of radiation-induced cancer from paediatric chest CT: two-year cohort study.

BACKGROUND: The increasing absolute number of paediatric CT scans raises concern about the safety and efficacy and the effects of consecutive diagnostic ionising radiation. OBJECTIVE: To demonstrate a method to evaluate the lifetime attributable risk of cancer incidence/mortality due to a single low-dose helical chest CT in a two-year patient cohort. MATERIALS AND METHODS: A two-year cohort of 522 paediatric helical chest CT scans acquired using a dedicated low-dose protocol were analysed retrospectively. Patient-specific estimations of radiation doses were modelled using three different mathematical phantoms. Per-organ attributable cancer risk was then estimated using epidemiological models. Additional comparison was provided for naturally occurring risks. RESULTS: Total lifetime attributable risk of cancer incidence remains low for all age and sex categories, being highest in female neonates (0.34%). Summation of all cancer sites analysed raised the relative lifetime attributable risk of organ cancer incidence up to 3.6% in female neonates and 2.1% in male neonates. CONCLUSION: Using dedicated scan protocols, total lifetime attributable risk of cancer incidence and mortality for chest CT is estimated low for paediatric chest CT, being highest for female neonates.

Left atrial volume in chronic obstructive pulmonary disease.

PURPOSE: The aim of the study was to evaluate left atrial (LA) volume in smokers according to the severity of emphysema, with the objective of providing indirect evidence of reduced pulmonary venous return due to capillary destruction. MATERIALS AND METHODS: A total of 121 smokers underwent a high-pitch and high-temporal resolution computed tomography (CT) angiographic examination, enabling quantification of emphysema, total lung volume, and LA volume measurements normalized to body surface area. RESULTS: The CT phenotypes were as follows: emphysema predominant (group 1; n=57); airway predominant (group 2; n=30); a mixed pattern of emphysema and airway disease (group 3; n=15); and absence of bronchopulmonary CT abnormalities (group 4; n=19). A negative correlation was found between the indexed LA volume and the percentage of emphysema: (a) in the overall study group (P=0.032; r=-0.19); (b) in group 1 (P=0.0163; r=-0.32); and (c) in groups 1 and 3 when analyzed together (P=0.0492; r=-0.23). A negative correlation was found between the indexed LA volume and the total lung volume in the overall study group (P=0.039; r=-0.19) and in group 1 (P=0.048; r=-0.26), whereas no correlations were found in group 2 (P=0.44; r=-0.15), group 3 (P=0.52; r=-0.17), and groups 1 and 3 analyzed as a whole (P=0.14; r=-0.17). CONCLUSIONS: The indexed LA volume, impacting left ventricular preload, is correlated to the severity of emphysema.

Perfusion CT allows prediction of therapy response in non-small cell lung cancer treated with conventional and anti-angiogenic chemotherapy.

OBJECTIVES: To determine whether CT can depict early perfusion changes in lung cancer treated by anti-angiogenic drugs, allowing prediction of response. METHODS: Patients with non-small cell lung cancer, treated by conventional chemotherapy with (Group 1; n = 17) or without (Group 2; n = 23) anti-vascular endothelial growth factor (anti-VEGF) drug (bevacizumab) underwent CT perfusion before (TIME 0) and after 1 (TIME 1), 3 (TIME 2) and 6 (TIME 3) cycles of chemotherapy. The CT parameters evaluated included: (1) total tumour vascular volume (TVV) and total tumour extravascular flow (TEF); (2) RECIST (Response Evaluation Criteria in Solid Tumours) measurements. Tumour response was also assessed on the basis of the clinicians' overall evaluation. RESULTS: In Group 1, significant reduction in perfusion was identified between baseline and: (1) TIME 1 (TVV, P = 0.0395; TEF, P = 0.015); (2) TIME 2 (TVV, P = 0.0043; TEF, P < 0.0001); (3) TIME 3 (TVV, P = 0.0034; TEF, P = 0.0005) without any significant change in Group 2. In Group 1: (1) the reduction in TVV at TIME 1 was significantly higher in responders versus non-responders at TIME 2 according to RECIST (P = 0.0128) and overall clinicians' evaluation (P = 0.0079); (2) all responders at TIME 2 had a concurrent decrease in TVV and TEF at TIME 1. CONCLUSION: Perfusion CT demonstrates early changes in lung cancer vascularity under anti-angiogenic chemotherapy that may help predict therapeutic response. KEY POINTS: • Perfusion CT has the potential of providing in vivo information about tumour vasculature. • CT depicts early and specific perfusion changes in NSCLC under anti-angiogenic drugs. • Specific therapeutic effects of anti-angiogenic drugs can be detected before tumour shrinkage. • Early perfusion changes can help predict therapeutic response to anti-angiogenic treatment. • Perfusion CT could be a non-invasive tool to monitor anti-angiogenic treatment.

Imaging the heart-lung relationships during a chest computed tomography examination: is electrocardiographic gating the only option?

Before the advent of fast-scanning multidetector-row computed tomography (CT) technology, thoracic CT studies were exclusively used for the morphologic assessment of thoracic organs, as the concurrent examination of the heart was hampered by image degradation from cardiac motion artifacts. The introduction of fast rotation speed and dedicated cardiac reconstruction algorithms has opened new possibilities for chest imaging, starting with the possibility to integrate cardiac morphologic and functional information into a diagnostic CT scan of the chest. Initiated with 16-slice multidetector-row CT, this concept of integrating morphology and function has been further simplified with 64-slice CT scanners, thus allowing radiologists to provide vital information in the management of patients with a wide variety of acute or chronic respiratory disorders. Because this CT technology offers the possibility of generating high-resolution and motion-free images of the coronary arteries, evaluation of the coronary arteries during CT examinations of the chest should further widen the clinical applications of CT for respiratory patients, keeping in mind that cigarette smoking is a shared risk factor for both impaired lung function and cardiovascular events. The recent advent of high temporal resolution and high pitch modes with dual-source CT simplifies the concept of integrated cardiothoracic imaging, introducing non-electrocardiographic-gated coronary artery imaging. The purpose of this article is to review the successive approaches of these redefined borders of thoracic imaging.