Accuracy of Ultralow-Dose Photon-counting CT in the Detection of Lung Changes after Lung Transplant.

Background Data on the diagnostic accuracy of ultralow-dose (ULD) CT protocols for periodic surveillance in recipients of lung transplant are lacking. Purpose To assess the potential for radiation dose reduction using ULD photon-counting CT (PCT) to detect lung abnormalities in recipients of lung transplant during repeat CT follow-up. Materials and Methods Consecutive adult recipients of lung transplant undergoing same-day standard-of-care low-dose (LD) and ULD PCT from March 2023 to May 2023 were prospectively included. The ULD protocols were performed with two target effective doses comprising 20% (hereafter, ULD1) and 10% (hereafter, ULD2) of the standard LD protocol. The 1-mm reconstructions were reviewed by three readers. Subjective image quality, the visibility of certain anatomic structures (using a five-point Likert scale), and the presence of lung abnormalities were independently assessed. The χ2 or t tests were used to evaluate differences between the ULD1 and ULD2 protocols. Results A total of 82 participants (median age, 64 years [IQR, 54-69 years]; 47 male) were included (41 participants for each ULD protocol). The mean effective doses per protocol were 1.41 mSv ± 0.44 (SD) for LD, 0.26 mSv ± 0.08 for ULD1, and 0.17 mSv ± 0.04 for ULD2. According to three readers, the subjective image quality of the ULD images was deemed diagnostic (Likert score ≥3) in 39-40 (ULD1) and 40-41 (ULD2) participants, and anatomic structures could be adequately visualized (Likert score ≥3) in 33-41 (ULD1) and 34-41 (ULD2) participants. The detection accuracy for individual lung anomalies exceeded 70% for both ULD protocols, except for readers 1 and 3 detecting proximal bronchiectasis and reader 3 detecting bronchial wall thickening and air trapping. No evidence of a statistically significant difference in noise (P = .96), signal-to-noise ratio (P = .77), or reader accuracy (all P ≥ .05) was noted between the ULD protocols. Conclusion ULD PCT was feasible for detecting lung abnormalities following lung transplant, with a tenfold radiation dose reduction. © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Ciet in this issue.

Intercostal Lung Hernias Presenting After Minimally Invasive Cardiac Surgery.

INTRODUCTION: With the introduction of minimally invasive cardiac surgery, more commonly cases of lung herniation are starting to appear. Acquired lung hernias are classified as postoperative, traumatic, pathologic, and spontaneous. Up to 83% of lung hernias are intercostal. Herein, we describe patients presenting with intercostal lung hernias following minimally invasive cardiac surgery at a single center in Medellín, Colombia. METHODS: We conducted a retrospective search of all patients presenting with intercostal lung hernias secondary to minimally invasive cardiac surgery at our clinic in Medellín since the beginning of our program, from 2010 to 2022. Mini-sternotomies were excluded from our study. We reviewed the incision type and other possible factors leading to intercostal lung hernia development. We also describe the approach taken for these patients. RESULTS: From 2010 up until 2022, 803 adult patients underwent minimally invasive cardiac surgeries through a mini-thoracotomy. At the time of data retrieval, nine patients presented with intercostal lung hernias at the previous incision site. Five hernias (55%) were from right 2nd intercostal parasternal mini-thoracotomies for aortic valve surgeries. Four hernias (45%) were from right 4th intercostal lateral mini-thoracotomies for mitral valve surgeries. Our preferred repair technique is a video-assisted thoracoscopic mesh approach. CONCLUSION: Minimally invasive cardiac surgical approaches are becoming more routine. Proper wound closure is critical in preventing lung hernias. Additionally, timely diagnosis and opportune hernia surgery using video-assisted thoracoscopic mesh repair can prevent further complications.

Effect of perioperative sigh ventilation on postoperative hypoxemia and pulmonary complications after on-pump cardiac surgery (E-SIGHT): study protocol for a randomized controlled trial.

BACKGROUND: Postoperative hypoxemia and pulmonary complications remain a frequent event after on-pump cardiac surgery and mostly characterized by pulmonary atelectasis. Surfactant dysfunction or hyposecretion happens prior to atelectasis formation, and sigh represents the strongest stimulus for surfactant secretion. The role of sigh breaths added to conventional lung protective ventilation in reducing postoperative hypoxemia and pulmonary complications among cardiac surgery is unknown. METHODS: The perioperative sigh ventilation in cardiac surgery (E-SIGHT) trial is a single-center, two-arm, randomized controlled trial. In total, 192 patients scheduled for elective cardiac surgery with cardiopulmonary bypass (CPB) and aortic cross-clamp will be randomized into one of the two treatment arms. In the experimental group, besides conventional lung protective ventilation, sigh volumes producing plateau pressures of 35 cmH2O (or 40 cmH2O for patients with body mass index > 35 kg/m2) delivered once every 6 min from intubation to extubation. In the control group, conventional lung protective ventilation without preplanned recruitment maneuvers is used. Lung protective ventilation (LPV) consists of low tidal volumes (6-8 mL/kg of predicted body weight) and positive end-expiratory pressure (PEEP) setting according to low PEEP/FiO2 table for acute respiratory distress syndrome (ARDS). The primary endpoint is time-weighted average SpO2/FiO2 ratio during the initial post-extubation hour. Main secondary endpoint is the severity of postoperative pulmonary complications (PPCs) computed by postoperative day 7. DISCUSSION: The E-SIGHT trial will be the first randomized controlled trial to evaluate the impact of perioperative sigh ventilation on the postoperative outcomes after on-pump cardiac surgery. The trial will introduce and assess a novel perioperative ventilation approach to mitigate the risk of postoperative hypoxemia and PPCs in patients undergoing cardiac surgery. Also provide the basis for a future larger trial aiming at verifying the impact of sigh ventilation on postoperative pulmonary complications. TRIAL REGISTRATION: ClinicalTrials.gov NCT06248320. Registered on January 30, 2024. Last updated February 26, 2024.

Lung microbiota: implications and interactions in chronic pulmonary diseases.

The lungs, as vital organs in the human body, continuously engage in gas exchange with the external environment. The lung microbiota, a critical component in maintaining internal homeostasis, significantly influences the onset and progression of diseases. Beneficial interactions between the host and its microbial community are essential for preserving the host's health, whereas disease development is often linked to dysbiosis or alterations in the microbial community. Evidence has demonstrated that changes in lung microbiota contribute to the development of major chronic lung diseases, including chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), asthma, and lung cancer. However, in-depth mechanistic studies are constrained by the small scale of the lung microbiota and its susceptibility to environmental pollutants and other factors, leaving many questions unanswered. This review examines recent research on the lung microbiota and lung diseases, as well as methodological advancements in studying lung microbiota, summarizing the ways in which lung microbiota impacts lung diseases and introducing research methods for investigating lung microbiota.

Right lung hypoplasia associated with polysplenia: A case report and literature review.

Pulmonary agenesis is a very rare congenital abnormality that can be missed in a routine radiographic examination, which delays diagnosis until adulthood. It can be associated with other congenital malformations, such as valvular heart disease and gastrointestinal organ abnormalities. Computed tomography (CT) is a useful modality for its better delineation of pulmonary and vascular structures. The reported case here is for an adult male who presented with dextroposition of the heart and was found to have a unilobed right lung associated with polysplenia. This has not been previously reported in the literature.

Mitochondrial Extracellular Vesicles: A Promising Avenue for Diagnosing and Treating Lung Diseases.

Mitochondria, pivotal organelles governing cellular biosynthesis, energy metabolism, and signal transduction, maintain dynamic equilibrium through processes such as biogenesis, fusion, fission, and mitophagy. Growing evidence implicates mitochondrial dysfunction in a spectrum of respiratory diseases including acute lung injury/acute respiratory distress syndrome, bronchial asthma, pulmonary fibrosis, chronic obstructive pulmonary disease, and lung cancer. Consequently, identifying methods capable of ameliorating damaged mitochondrial function is crucial for the treatment of pulmonary diseases. Extracellular vesicles (EVs), nanosized membrane vesicles released by cells into the extracellular space, facilitate intercellular communication by transferring bioactive substances or signals between cells or organs. Recent studies have identified abundant mitochondrial components within specific subsets of EVs, termed mitochondrial extracellular vesicles (mitoEVs), whose contents and compositions vary with disease progression. Moreover, mitoEVs have demonstrated reparative mitochondrial functions in injured recipient cells. However, a comprehensive understanding of mitoEVs is currently lacking, limiting their clinical translation prospects. This Review explores the biogenesis, classification, functional mitochondrial cargo, and biological effects of mitoEVs, with a focus on their role in pulmonary diseases. Emphasis is placed on their potential as biological markers and innovative therapeutic strategies in pulmonary diseases, offering fresh insights for mechanistic studies and drug development in various pulmonary disorders.

[Establishment of Nano-ITO induced rat model of indium lung disease and exploration of its pathological characteristics].

Objective: To study the dynamic pathological characteristics of lung tissue in a Nano-ITO induced rat model of indium lung disease and to guide clinical and basic scientific research to further explore the mechanisms of pulmonary interstitial injury and pulmonary alveolar proteinosis (PAP). Methods: Dose-response (three divided doses) and time-course studies (six exposure periods) were performed to investigate the pulmonary toxicity induced by Nano-ITO. At the end of the experiment, cytokine levels and oxidative stress were analyzed in the bronchoalveolar lavage fluid. Rat lung tissues were also collected for staining with H&E, PAS, Masson's, Oil Red O, and Sirius Red. Ultrastructure of lung tissue cells was observed by transmission electron microscopy. Expression of IL-1ß, HO-1, SP-A was observed by immunohistochemistry, and the expression of α-SMA was observed by immunofluorescence. Results: Nano-ITO intratracheal instillation caused pulmonary toxicity by inducing acute inflammation at 3 days, granuloma (nodule) formation and collagen hyperplasia at 14 days, and alveolar proteinosis at 56 days post-exposure. Pathological features of lung tissue included typical alveolar exudates, cellular fibrous nodules, enlarged alveolar fat droplet fusion, cholesterol crystal granuloma and pulmonary alveolar proteinosis. The intra-alveolar eosinophilic material (multilamellated, lattice-shaped, and myelin-like structure) showed abnormal lamellar bodies (features of alveolar type Ⅱ epithelial cells) and abundant rough endoplasmic reticulum and mitochondria (features of fibroblasts) on transmission electron microscopy of the lung tissue from rats exposed to Nano-ITO on the 84th day. Cellular pathology revealed that a large amount of amorphous PAS stain-positive substances appear in BALF at 28 days post-exposure, and pink granular protein-like substances can be seen in alveolar macrophages. Conclusions: There are three characteristic developmental stages in Nano-ITO induced pulmonary injury in rats, acute inflammation, granuloma (nodule) formation and collagen proliferation, and pulmonary alveolar proteinosis, which provide a reference feature model for the pathogenesis of indium lung disease.

Analysis of the waitlist performance and post-transplant outcomes of lung transplant in elderly recipients in Korea: A nationwide cohort study.

BACKGROUND: There is a lack of information on the waitlist performance and post-transplant outcomes of lung transplants in elderly recipients in Korea. METHODS: We retrospectively reviewed and analyzed data from the Korean Network for Organ Sharing database between March 2010 and August 2023. RESULTS: In total, 2574 patients were listed for lung transplantation during the study period, with 511 (19.9%) of them being over 65 years of age. Among these, 188 patients (36.8%) underwent transplantation, while 184 patients (36%) passed away without undergoing transplantation at the time of data extraction. The most prevalent underlying disease on the waitlist was idiopathic pulmonary fibrosis, accounting for 68.1%. The 1-year survival rate was significantly lower in the elderly compared to that in the nonelderly (65.4 vs. 75.4%; p = .004). In the multivariate Cox analysis, elderly (hazard ratio [HR], 1.49; 95% CI, 1.14-1.97; p = .004) and a high urgent status at registration (HR, 1.83; 95% CI, 1.40-2.40; p < .001) were significantly associated with post-transplant 1-year mortality. Kaplan-Meier curves demonstrated a significant difference in post-transplant mortality based on the urgency status at enrollment (χ2 = 8.302, p = .016). Even with the same highly urgent condition at the time of transplantation, different prognoses were observed depending on the condition at listing (χ2 = 9.056, p = .029). CONCLUSION: The elderly exhibited worse transplant outcomes than nonelderly adults, with a highly urgent status at registration identified as a significant risk factor. Unprepared, highly urgent transplantation was associated with poor outcomes.

Utility of serum uric acid levels in excluding pulmonary hypertension in severe chronic lung disease: insights from a tertiary care center.

Hyperuricemia is a known predictor of World Health Organization (WHO) Group 1 pulmonary hypertension (PH) (pulmonary arterial hypertension), but its role in excluding PH secondary to chronic lung diseases (WHO Group 3) remains unclear. We retrospectively analyzed data from 323 patients with severe chronic pulmonary diseases who underwent evaluation for lung transplantation at a tertiary medical center between June 2017 and February 2023. We examined the association between hyperuricemia (serum uric acid > 6 mg/dL or > 0.357 mmol/L) and PH [mean pulmonary arterial pressure (MPAP) > 20 mmHg]. Compared to the normouricemia group (n = 211), hyperuricemic patients (n = 112) were more likely to be younger (P = 0.02), male (P < 0.001), and present with PH (P = 0.001) and severe PH (MPAP > 35 mmHg; P < 0.001). These patients also had a higher body mass index (P = 0.004), plasma N-terminal pro-B-type natriuretic peptide (P < 0.001), serum creatinine (P < 0.001), and C-reactive protein levels (P = 0.03). Significant associations with PH included higher body mass index (P = 0.005), uric acid levels (P < 0.001), total lung capacity (P = 0.02), and residual volume (P = 0.01); shorter 6-min walk test distance (P = 0.005); and lower forced expiratory volume in one second (P = 0.006) and diffusing capacity for carbon monoxide (P < 0.001). Multivariate analysis showed elevated uric acid levels remained significantly associated with PH (OR 1.29, 95% CI 1.05-1.58, P = 0.01). In conclusion, normal serum uric acid levels serve as a significant predictor for excluding pulmonary hypertension in patients with severe chronic lung diseases.

Assessing the accuracy of the revised Cardiac Risk Index compared to the American Society of Anaesthesiologists physical status classification in predicting Pulmonary and Cardiac complications among non-cardiothoracic surgery patients at Muhimbili National Hospital: a prospective cohort study.

BACKGROUND: The Revised Cardiac Risk Index (RCRI) and the American Society of Anaesthesiologists (ASA-PS) classification system are two commonly used tools for preoperative risk assessment. This study aimed to assess the accuracy of RCRI compared to the ASA-PS classification system in preoperative risk assessment for pulmonary and cardiac problems among non-cardiothoracic surgery patients admitted at Muhimbili National Hospital (MNH). METHODS: This was a prospective cohort study design conducted from August 2022 to April 2023 among 184 patients of 18 years and above admitted at MNH for elective non-cardiothoracic surgery. Data Analysis was conducted using STATA software version 16. Means and standard deviations were used to summarize continuous data. Frequencies and percentages were used to summarize categorical data. The logistic regression and ROC curve analysis were used to determine the correlation between variables. RESULTS: The majority of patients (43.3%) had an RCRI score of 1 point, and 39.9% were classified as ASA class 1. Patients in ASA classes 3 and 4 had higher odds of developing cardiac and pulmonary complications (AUC = 0.75 and 0.77, respectively). Patients with an RCRI score of 2 or ≥ 3 points were also more likely to experience cardiac and pulmonary complications (AUC = 0.73 and 0.72, respectively). There was no significant difference in the predictive ability of the two tools. Both RCRI and ASA-PS classification systems were equally effective in predicting these complications. CONCLUSION: Both the RCRI and the ASA-PS classification system demonstrated good predictive ability for cardiac and pulmonary complications among patients undergoing non-cardiothoracic surgery.

The Relevance of the Endothelium in Cardiopulmonary Disorders.

The endothelium is a cell monolayer that lines vessels and separates tissues from blood flow. Endothelial cells (ECs) have a multitude of functions, including regulating blood flow and systemic perfusion through changes in vessel diameter. When an injury occurs, the endothelium is affected by altering its functions and structure, which leads to endothelial dysfunction, a characteristic of many vascular diseases. Understanding the role that the endothelium plays in pulmonary vascular and cardiopulmonary diseases, and exploring new therapeutic strategies is of utmost importance to advance clinically. Currently, there are several treatments able to improve patients' quality of life, however, none are effective nor curative. This review examines the critical role of the endothelium in the pulmonary vasculature, investigating the alterations that occur in ECs and their consequences for blood vessels and potential molecular targets to regulate its alterations. Additionally, we delve into promising non-pharmacological therapeutic strategies, such as exercise and diet. The significance of the endothelium in cardiopulmonary disorders is increasingly being recognized, making ECs a relevant target for novel therapies aimed at preserving their functional and structural integrity.

Efficacy of Lung Ultrasound vs Chest X-Ray in Detecting Lung Consolidation and Edema in Premature Infants in the NICU.

BACKGROUND The incidence of lung diseases in premature newborns is significantly higher than in full-term newborns due to their underdeveloped lungs. Ultrasound and X-ray are commonly-used bedside examinations in neonatology. This study primarily compares the efficacy of chest X-ray (CXR) and lung ultrasound (LUS) images in evaluating lung consolidation and edema in premature newborns at Neonatal Intensive Care Units (NICU). MATERIAL AND METHODS A retrospective analysis was conducted on LUS and CXR examination results, along with clinical records of premature newborns admitted to our hospital's NICU from November 1, 2019, to December 31, 2021. CXR and LUS scans were performed on the same newborn within a day. We evaluated the consolidations and edema by interpreting the CXR and LUS images, then compared the findings. RESULTS Out of 75 cases, 34 showed lung consolidations on LUS (45%), while only 14 exhibited consolidations on CXR (19%). The detection rate of consolidations by LUS was significantly higher compared to CXR (34/75 vs 14/75, P<0.001). Differences were observed between the 2 bedside examinations in identifying consolidations, with some cases seen only on LUS. CXR struggled to accurately assess the severity of lung edema visible on LUS, showing significant disparity in detecting interstitial edema (53/75 vs 21/75, P<0.001). CONCLUSIONS LUS outperforms chest CXR for bedside assessment of lung consolidation and edema in premature newborns.

Pulmonary Crystal-Storing Histiocytosis Misdiagnosed as Lung Cancer.

BACKGROUND: Crystalloid storage histiocytosis (CSH) is a rare clinical condition characterized by abnormally high numbers of histiocytes with a large accumulation of crystalline immunoglobulins. Due to its relative rarity, clinical diagnosis of it is frequently incomplete or incorrect. We report a case with pulmonary crystal-storing histiocytosis that was mistakenly identified as lung carcinoma. METHODS: Percutaneous lung biopsy, bronchoscopy. RESULTS: Percutaneous lung biopsy pathology shows granulomatous inflammation with massive eosinophilic infiltration, immunohistochemistry shows CD68, kappa positive, S-100, desmin, myogenin, lambda negative. The final diagnosis is pulmonary crystal-storing histiocytosis. CONCLUSIONS: To get pathology tissue for a definitive diagnosis, patients with pulmonary nodules who have changes in tumor markers or nodule size should have bronchoscopy or percutaneous lung biopsy done as soon as possible.

Significance of changes in cavity after treatment in Mycobacterium avium complex pulmonary disease.

Cavities are characteristic radiological features related to increased mycobacterial burden and poor prognosis in Mycobacterium avium complex pulmonary disease (MAC-PD). However, cavity changes following treatment and their clinical implications remain unknown. We aimed to elucidate whether cavity obliteration or reduction in cavity size or wall thickness correlates with microbiological cure. In total, 136 adult patients with cavitary MAC-PD treated for ≥ 6 months between January 1st, 2009, and December 31st, 2021, in a tertiary referral centre in South Korea were enrolled. The cavity with the largest diameter at treatment initiation was tracked for size and thickness changes. Following median treatment of 20.0 months, 74 (54.4%) patients achieved microbiological cure. Cavity obliteration, achieved in 58 (42.6%) patients at treatment completion, was independently associated with microbiological cure. In patients with persistent cavities, size reduction of ≥ 10% was significantly associated with microbiological cure, whereas thickness reduction was not. Five-year mortality rates in patients with cavity obliteration, persistent but reduced cavity, and persistent cavity without shrinkage were 95.6%, 72.1%, and 65.3%, respectively (P < 0.001). In conclusion, cavity obliteration or shrinkage at treatment completion is associated with microbiological cure and reduced mortality in MAC-PD, suggesting that cavity changes could serve as a proxy indicator for treatment response.

Postoperative pulmonary complications after major abdominal surgery in elderly patients and its association with patient-controlled analgesia.

OBJECTIVES: This study aims to identify the risk factors for postoperative pulmonary complications (PPCs) in elderly patients undergoing major abdominal surgery and to investigate the relationship between patient-controlled analgesia (PCA) and PPCs. DESIGN: A retrospective study. METHOD: Clinical data and demographic information of elderly patients (aged ≥ 60 years) who underwent upper abdominal surgery at the First Affiliated Hospital of Sun Yat-sen University from 2017 to 2019 were retrospectively collected. Patients with PPCs were identified using the Melbourne Group Scale Version 2 scoring system. A directed acyclic graph was used to identify the potential confounders, and multivariable logistic regression analyses were conducted to identify independent risk factors for PPCs. Propensity score matching was utilized to compare PPC rates between patients with and without PCA, as well as between intravenous PCA (PCIA) and epidural PCA (PCEA) groups. RESULTS: A total of 1,467 patients were included, with a PPC rate of 8.7%. Multivariable analysis revealed that PCA was an independent protective factor for PPCs in elderly patients undergoing major abdominal surgery (odds ratio = 0.208, 95% confidence interval = 0.121 to 0.358; P < 0.001). After matching, patients receiving PCA demonstrated a significantly lower overall incidence of PPCs (8.6% vs. 26.3%, P < 0.001), unplanned transfer to the intensive care unit (1.1% vs. 8.4%, P = 0.001), and in-hospital mortality (0.7% vs. 5.3%, P = 0.021) compared to those not receiving PCA. No significant difference in outcomes was observed between patients receiving PCIA or PCEA after matching. CONCLUSION: Patient-controlled analgesia, whether administered intravenously or epidurally, is associated with a reduced risk of PPCs in elderly patients undergoing major upper abdominal surgery.

Effectiveness of Amikacin liposome inhalation suspension for refractory Mycobacterium avium complex pulmonary disease at 6 months post initiation.

BACKGROUND: Amikacin  liposome inhalation suspension (ALIS) improved sputum culture conversion rate at 6 months for patients with refractory Mycobacterium avium complex pulmonary disease (MAC-PD) in an international phase 3 trial. Patient characteristics and chest high-resolution CT (HRCT) findings associated with ALIS effectiveness are poorly documented. OBJECTIVE: We aimed to clarify ALIS effectiveness for refractory MAC-PD at 6 months, elucidating associated patient characteristics and chest CT findings. METHODS: We reviewed medical records of 12 patients with refractory MAC-PD for whom ALIS treatment was initiated at Toho University Omori Medical Center from November 2021 through September 2022. All patients demonstrated treatment persistence for at least 3 months. They were divided into culture conversion and non-conversion groups using sputum culture conversion status after 6-month ALIS treatment initiation. Clinical and radiological characteristics were compared. RESULTS: Seven of the 12 patients (58.3%) achieved sputum culture conversion within 6 months. The culture conversion group had shorter pre-ALIS initiation treatment duration [21 months (16-25) vs. 62 months (32-69); p = 0.045]; lower cavitary lesion incidence on HRCT (28.6% vs. 100%; p = 0.028); and fewer clarithromycin (CLA)-resistant strains [0/7 (0%) vs. 3/5 (60%); p = 0.045]. Chest HRCT findings improved in 4 of 7 (57.1%) and 1 of 5 (20%) patients in the culture conversion and non-conversion groups, respectively. CONCLUSION: ALIS facilitated sputum culture conversion within 6 months in 58.3% of patients with refractory MAC-PD. Sputum culture conversion was significantly more frequent for CLA-susceptible strains and patients with fewer cavitary lesions. Improved CT findings after ALIS did not always correspond to sputum culture conversion.

Longitudinal registration of thoracic CT images with radiation-induced lung diseases: A divide-and-conquer approach based on component structure wise registration using coherent point drift.

BACKGROUND AND OBJECTIVE: Registration of pulmonary computed tomography (CT) images with radiation-induced lung diseases (RILD) was essential to investigate the voxel-wise relationship between the formation of RILD and the radiation dose received by different tissues. Although various approaches had been developed for the registration of lung CTs, their performances remained clinically unsatisfactory for registration of lung CT images with RILD. The main difficulties arose from the longitudinal change in lung parenchyma, including RILD and volumetric change of lung cancers, after radiation therapy, leading to inaccurate registration and artifacts caused by erroneous matching of the RILD tissues. METHODS: To overcome the influence of the parenchymal changes, a divide-and-conquer approach rooted in the coherent point drift (CPD) paradigm was proposed. The proposed method was based on two kernel ideas. One was the idea of component structure wise registration. Specifically, the proposed method relaxed the intrinsic assumption of equal isotropic covariances in CPD by decomposing a lung and its surrounding tissues into component structures and independently registering the component structures pairwise by CPD. The other was the idea of defining a vascular subtree centered at a matched branch point as a component structure. This idea could not only provide a sufficient number of matched feature points within a parenchyma, but avoid being corrupted by the false feature points resided in the RILD tissues due to globally and indiscriminately sampling using mathematical operators. The overall deformation model was built by using the Thin Plate Spline based on all matched points. RESULTS: This study recruited 30 pairs of lung CT images with RILD, 15 of which were used for internal validation (leave-one-out cross-validation) and the other 15 for external validation. The experimental results showed that the proposed algorithm achieved a mean and a mean of maximum 1 % of average surface distances <2 and 8 mm, respectively, and a mean and a maximum target registration error <2 mm and 5 mm on both internal and external validation datasets. The paired two-sample t-tests corroborated that the proposed algorithm outperformed a recent method, the Stavropoulou's method, on the external validation dataset (p < 0.05). CONCLUSIONS: The proposed algorithm effectively reduced the influence of parenchymal changes, resulting in a reasonably accurate and artifact-free registration.