The breadth of the diaphragm: updates in embryogenesis and role of imaging

Investigation of the correlation between the change in the projected lung area and forced vital capacity using biphasic chest dynamic digital radiography: a cross-sectional study

Background

Chest dynamic digital radiography (DDR) is used as a supplementary tool for the routine pulmonary function test (PFT); however, its potential as a novel standard PFT method has yet to be explored. Therefore, the present study aimed to investigate the correlation between the change in the projected lung area (ΔPLA) and forced vital capacity (FVC) using chest DDR, and to establish a DDR-FVC estimation model and a predictive value model for the ΔPLA.

Methods

In total, 139 participants who underwent chest DDR and the PFT in the same period at The First Affiliated Hospital of Guangzhou Medical University from April 2022 to February 2023 were prospectively included in the study. The patients' age, gender, height, and weight measurements were recorded. Additionally, the ΔPLA was measured, and the IWS workstation software was used for automated outlining and calculation. Subsequently, a correlation analysis and regression analysis models were employed to examine the relationship between the ΔPLA, FVC, and individual physiological characteristics. Additionally, an independent sample t-test was used to determine whether there were any significant differences between the normal and abnormal FVC groups.

Results

The 139 participants were grouped according to the results of the ratio of measured/predicted FVC values (FVC%pred); those with an FVC%pred ≥80%, were allocated to the normal FVC group, and those with an FVC%pred <80% were allocated to the abnormal FVC group. The correlation coefficient was >0.8 in the full sample; the ΔPLA showed a significant linear correlation with the measured FVC value [r=0.81, 95% confidence interval (CI): 0.75-0.86, P<0.001]. There was a significant difference in the ΔPLA between the normal and abnormal FVC groups. With the ΔPLA, age, gender, height, and weight as predictor variables, the following DDR-FVC estimation model was established: DDR-FVC estimation model = -0.997 + 1.35×10-4 × ΔPLA + 0.017 × height - 0.014 × age + 0.249 × gender (1 for male and 0 for female) [adjusted R2 (adj. R2)=0.731, F=94.615, P<0.001]. The following formula was used to determine the predictive value of the ΔPLA: Predictive value of ΔPLA = -12,504.287 + 173.185 × height + 62.971 × weight - 84.933 × age (adj. R2=0.393, F=20.453, P<0.001).

Conclusions

There was a linear correlation between the ΔPLA measured by biphasic chest DDR and the FVC. A model for estimating the FVC was established based on the ΔPLA, which allows the FVC to be assessed by the ΔPLA measured by biphasic chest DDR. A predictive value model for the ΔPLA was also established to provide ΔPLA reference values for assessment and comparison.

Prenatal Diagnosis of an Intrathoracic Left Kidney Associated with Congenital Diaphragmatic Hernia: Case Report and Systematic Review

INTRODUCTION

A congenital intrathoracic kidney (ITK) is a rare anomaly that is recognized to have four causes: renal ectopia with an intact diaphragm, diaphragmatic eventration, diaphragmatic hernia, and traumatic diaphragmatic rupture. We report a case of a prenatal-diagnosed ITK related to a congenital diaphragmatic hernia (CDH) and conducted a systematic review of all cases of the prenatal diagnosis of this association.

CASE PRESENTATION

A fetal ultrasound scan at 22 gestational weeks showed left CDH and ITK, hyperechoic left lung parenchyma, and mediastinal shift. The fetal echocardiography and karyotype were normal. Magnetic resonance imaging at 30 gestational weeks confirmed the ultrasound suspicion of left CDH in association with bowel and left kidney herniation. The fetal growth, amniotic fluid, and Doppler indices remained within the normal range over time. The woman delivered the newborn via an at-term spontaneous vaginal delivery. The newborn was stabilized and underwent non-urgent surgical correction; the postoperative course was uneventful.

CONCLUSIONS

CDH is the rarest cause of ITK; we found only eleven cases describing this association. The mean gestational age at diagnosis was 29 ± 4 weeks and 4 days. There were seven cases of right and four cases of left CDH. There were associated anomalies in only three fetuses. All women delivered live babies, the herniated kidneys showed no functional damage after their surgical correction, and the prognosis was favorable after surgical repair. The prenatal diagnosis and counseling of this condition are important in planning adequate prenatal and postnatal management in order to improve neonatal outcomes.

Embryology of the Abdominal Wall and Associated Malformations—A Review

In humans, the incidence of congenital defects of the intraembryonic celom and its associated structures has increased over recent decades. Surgical treatment of abdominal and diaphragmatic malformations resulting in congenital hernia requires deep knowledge of ventral body closure and the separation of the primary body cavities during embryogenesis. The correct development of both structures requires the coordinated and fine-tuned synergy of different anlagen, including a set of molecules governing those processes. They have mainly been investigated in a range of vertebrate species (e.g., mouse, birds, and fish), but studies of embryogenesis in humans are rather rare because samples are seldom available. Therefore, we have to deal with a large body of conflicting data concerning the formation of the abdominal wall and the etiology of diaphragmatic defects. This review summarizes the current state of knowledge and focuses on the histological and molecular events leading to the establishment of the abdominal and thoracic cavities in several vertebrate species. In chronological order, we start with the onset of gastrulation, continue with the establishment of the three-dimensional body shape, and end with the partition of body cavities. We also discuss well-known human etiologies.

Magnetic Resonance Imaging of the Diaphragm: From Normal to Pathologic Findings

The diaphragm is a musculotendinous structure that divides the chest from the abdomen. Its motility, unintentional or voluntary, is crucial for the physiologic respiratory function due to its contribution to lung volume expansion and contraction. Therefore, diaphragmatic dysfunction may cause a respiratory failure without any pathology of the lungs. Different imaging modalities can be employed for diaphragmatic evaluation. Among all, magnetic resonance imaging (MRI) has demonstrated to be the most accurate technique in providing a morphologic and functional assessment of the diaphragm as well as information about the adjacent structures. However, its diagnostic value is still underrated and its performance is often far from the daily clinical practice. Backward, physicians and radiologists should be aware of the undoubted advantages of MRI and confident about the normal or pathologic imaging features, to avoid misdiagnosis.