Histogram based analysis of lung perfusion of children after congenital diaphragmatic hernia repair

Functional lung imaging of 2-year-old children after congenital diaphragmatic hernia repair using dynamic mode decomposition MRI

OBJECTIVES

To investigate the feasibility of non-contrast-enhanced functional lung imaging in 2-year-old children after congenital diaphragmatic hernia (CDH) repair.

METHODS

Fifteen patients after CDH repair were examined using non-contrast-enhanced dynamic magnetic resonance imaging (MRI). For imaging two protocols were used during free-breathing: Protocol A with high temporal resolution and Protocol B with high spatial resolution. The dynamic images were then analysed through a recently developed post-processing method called dynamic mode decomposition (DMD) to obtain ventilation and perfusion maps. The ventilation ratios (VRatio) and perfusion ratios (QRatio) of ipsilateral to contralateral lung were compared to evaluate functional differences. Lastly, DMD MRI-based perfusion results were compared with perfusion parameters obtained using dynamic contrast-enhanced (DCE) MRI to assess agreement between methods.

RESULTS

Both imaging protocols successfully generated pulmonary ventilation (V) and perfusion (Q) maps in all patients. Overall, the VRatio and QRatio values were 0.84 ± 0.19 and 0.70 ± 0.24 for Protocol A, and 0.88 ± 0.18 and 0.72 ± 0.23 for Protocol B, indicating reduced ventilation ( p < 0.05 ) and perfusion ( p < 0.01 ) on the ipsilateral side. Moreover, there is a very strong positive correlation ( r > 0.89 , p < 0.01 ) and close agreement between DMD MRI-based perfusion values and DCE MRI-based perfusion parameters.

CONCLUSIONS

DMD MRI can obtain pulmonary functional information in 2-year-old CDH patients. The results obtained with DMD MRI correlate with DCE MRI, without the need for ionising radiation or exposure to contrast agents. While further studies with larger cohorts are warranted, DMD MRI is a promising option for functional lung imaging in CDH patients.

CLINICAL RELEVANCE STATEMENT

We demonstrate that pulmonary ventilation and perfusion information can be obtained in 2-year-old patients after CDH repair, without the need for ionising radiation or contrast agents by utilising non-contrast-enhanced MRI acquisitions together with dynamic mode decomposition analysis.

KEY POINTS

• Non-contrast-enhanced functional MR imaging is a promising option for functional lung imaging in 2-year-old children after congenital diaphragmatic hernia. • DMD MRI can generate pulmonary ventilation and perfusion maps from free-breathing dynamic acquisitions without the need for ionising radiation or contrast agents. • Lung perfusion parameters obtained with DMD MRI correlate with perfusion parameters obtained using dynamic contrast-enhanced MRI.

Postoperative pulmonary vascular growth in patients with congenital diaphragmatic hernia

BACKGROUND

Postoperative pulmonary growth in congenital diaphragmatic hernias (CDH) remains unclear. We investigated postoperative pulmonary vascular growth using serial lung perfusion scintigraphy in patients with CDH.

METHODS

Neonates with left CDH who underwent surgery and postoperative lung perfusion scintigraphy at our institution between 2001 and 2020 were included. Patient demographics, clinical courses, and lung scintigraphy data were retrospectively analyzed by reviewing medical records.

RESULTS

Twenty-one patients with CDH were included. Of these, 10 underwent serial lung scintigraphy. The ipsilateral perfusion rate and median age on the 1st and serial lung scintigraphy were 32% (34 days) and 33% (3.6 years), respectively. Gestational age at prenatal diagnosis (p = 0.02), alveolar-arterial oxygen difference (A-aDO2) at birth (p = 0.007), and preoperative nitric oxide (NO) use (p = 0.014) significantly correlated with the 1st lung scintigraphy. No other variables, including operative approach, were significantly correlated with the 1st or serial scintigraphy findings. All patients improved lung perfusion with serial studies [Difference:  + 7.0 (4.3-13.25) %, p = 0.001, paired t-test]. This improvement was not significantly correlated with preoperative A-aDO2 (p = 0.96), NO use (p = 0.28), or liver up (p = 0.90). The difference was significantly larger in patients who underwent thoracoscopic repair than in those who underwent open abdominal repair [+ 10.6 (5.0-17.1) % vs. + 4.25 (1.2-7.9) %, p = 0.042].

CONCLUSION

Our study indicated a postoperative improvement in ipsilateral lung vascular growth, which is possibly enhanced by a minimally invasive approach, in patients with CDH.

Long-Term Evaluation of the Shape of the Reconstructed Diaphragm in Patients with Left-Sided Congenital Diaphragmatic Hernia Using Serial Chest Radiographs and Correlation to Further Complications

Background: Defining risk factors for long-term comorbidities in patients after neonatal repair of congenital diaphragmatic hernia (CDH) is an important cornerstone of the implementation of targeted longitudinal follow-up programs. Methods: This study systematically assessed serial chest radiographs of 89 patients with left-sided CDH throughout a mean follow-up of 8.2 years. These geometrical variables for the left and right side were recorded: diaphragmatic angle (LDA, RDA), diaphragmatic diameter (LDD, RDD), diaphragmatic height (LDH, RDH), diaphragmatic curvature index (LDCI, RDCI), lower lung diameter (LLLD, RLLD) and thoracic area (LTA, RTA). Results: It was demonstrated that the shape of the diaphragm in patients with large defects systematically differs from that of patients with small defects. Characteristically, patients with large defects present with a smaller LDCI (5.1 vs. 8.4, p < 0.001) at 6 months of age, which increases over time (11.4 vs. 7.0 at the age of 15.5 years, p = 0.727), representing a flattening of the patch and the attached rudimentary diaphragm as the child grows. Conclusions: Multiple variables during early follow-up were significantly associated with comorbidities such as recurrence, scoliotic curves of the spine and a reduced thoracic area. Some geometrical variables may serve as surrogate parameters for disease severity, which is associated with long-term comorbidities.

Long term outcomes in CDH: Cardiopulmonary outcomes and health related quality of life

BACKGROUND

With improvements in clinical management and an increase in CDH survivorship there is a crucial need for better understanding of long-term health outcomes in CDH.

AIM

To investigate the prevalence of cardiopulmonary health morbidity and health related quality of life (HRQoL) in CDH survivors.

METHODS

We included all studies (n = 65) investigating long-term cardiopulmonary outcomes in CDH patients more than 2 years published in the last 30 years. The Newcastle-Ottawa Scale and the CASP checklist for cohort studies were utilized to assess study quality. Results were reported descriptively and collated by age group where possible.

RESULTS

The incidence of pulmonary hypertension was highly variable (4.5-38%), though rates (%) appeared to diminish after 5 years of age. Lung function indices and radiological outcomes were frequently abnormal, and Health Related Quality of Life (HRQoL) reduced also. Long term diseases notably emphysema and COPD are not yet fully described in the contemporary literature.

CONCLUSION

This study underscores cardiopulmonary health morbidity and a reduced HRQoL among CDH survivors. Where not already available dedicated multidisciplinary follow-up clinics should be established to support these vulnerable patients transition safely into adulthood. Future research is therefore needed to investigate the risk factors for cardiopulmonary ill health and morbidity in CDH survivors.

TYPE OF STUDY

Systematic review of case control and cohort studies.

Novel Use of a Bronchial Blocker in a Challenging Case of Congenital Diaphragmatic Hernia—A Case Report

The diagnosis of congenital diaphragmatic hernia (CDH) is associated with significant morbidity and mortality. Survival of neonates with CDH has improved recently, although the clinical course is complicated by sequelae of hypoplastic pulmonary parenchyma and vasculature, pulmonary hypertension, ventilation/perfusion (V/Q) mismatch, reduced pulmonary function and poor somatic growth. In this case report, we describe an infant with an antenatal diagnosis of CDH with a poor prognosis who underwent initial surgery followed by a tracheostomy but had a worsening clinical course due to a large area of ventilated but poorly perfused lung based on a V/Q nuclear scintigraphy scan. The emphysematous left lung was causing mediastinal shift and compression of the right lung, further compromising gas exchange. The infant had clinical improvement following bronchial blockade of the under-perfused left lung. This paved the way for further management with resection of the under-perfused lung lobe and continued clinical improvement. We present the novel use of selective bronchial blockade in a challenging case of CDH to determine if surgical lung resection may benefit the infant. We also review the physiology of gas exchange during the use of a bronchial occluder and the relevant literature.

Epidemiology of swallow dysfunction in CDH patients

PURPOSE

There is a growing body of literature regarding long-term pulmonary outcomes in children with congenital diaphragmatic hernia (CDH). Oral feeding skills in these children are often delayed. Chronic descending aspiration due to uncoordinated swallowing can further insult the already compromised lung parenchyma in these children. This study describes patterns of swallowing dysfunction and aspiration in patients with CDH.

METHODS

Records of all children treated for CDH at our institution from January 2014 to December 2019 were reviewed. Concern for swallowing dysfunction was marked by performance of a video-fluoroscopic swallow study (VFSS). We determined the frequency of aspiration on VFSS and how frequently that finding changed patient management. We also evaluated for association between clinical suspicion of swallow dysfunction and descriptors of CDH severity.

RESULTS

Sixty-nine patients were treated during this 6-year time period. Of those, 10 (14%) had a VFSS as an inpatient, and 25 (36%) had one as an outpatient. Eight (80%) inpatient and 17 (68%) outpatient studies identified aspiration. VFSS results changed management in 80% of patients, often by altering the consistency of oral feeds. There were no associations between CDH side, defect size or need for a patch and need for a VFSS.

CONCLUSIONS

The frequency of aspiration in the CDH population is high. Identification of aspiration on VFSS leads to changes in treatment aimed at protecting the lungs. Additionally, the severity of the CDH was not associated with aspiration on VFSS.

Longitudinal Analysis of Ventilation Perfusion Mismatch in Congenital Diaphragmatic Hernia Survivors

OBJECTIVE

To determine the natural history of pulmonary function for survivors of congenital diaphragmatic hernia (CDH).

STUDY DESIGN

This was a retrospective cohort study of survivors of CDH born during 1991-2016 and followed at our institution. A generalized linear model was fitted to assess the longitudinal trends of ventilation (V), perfusion (Q), and V/Q mismatch. The association between V/Q ratio and body mass index percentile as well as functional status was also assessed with a generalized linear model.

RESULTS

During the study period, 212 patients had at least one V/Q study. The average ipsilateral V/Q of the cohort increased over time (P < .01), an effect driven by progressive reduction in relative perfusion (P = .012). A higher V/Q ratio was correlated with lower body mass index percentile (P < .001) and higher probability of poor functional status (New York Heart Association class III or IV) (P = .045).

CONCLUSIONS

In this cohort of survivors of CDH with more severe disease characteristics, V/Q mismatch worsens over time, primarily because of progressive perfusion deficit of the ipsilateral side. V/Q scans may be useful in identifying patients with CDH who are at risk for poor growth and functional status.