Bilateral Lower Lobes Research Articles

SYNDROMIC DIAGNOSIS IN A CHILD WITH POST RENAL TRANSPLANT

9 Years old boy who underwent renal transplant, on immunosuppression for past 2 years presented with chronic abdomen pain. Oesophageal biopsy done outside showed features of post-transplant lymphoproliferative disorder (PTLD). He presented with fast breathing and was found to have acute renal dysfunction and severe anaemia requiring transfusion along with leukopenia. Chest X ray showed bilateral lower lobe consolidation. Acute on chronic graft dysfunction was suspected and he was evaluated for PTLD and infections as a cause. Epstein-Barr Virus (EBV) and BK virus was negative. Repeat oesophageal biopsy showed ulceration with cytomegaloviral inclusions. The diagnosis of Cytomegaloviral (CMV) syndrome was made as CMV viral counts were signicantly elevated. He was treated with parenteral ganciclovir and other supportive treatment following which his renal parameters showed dramatic improvement. Infectious causes should always be considered in post renal transplant. CMV infection is common between 30 and 90 days after transplantation. But this child presented after 2 years with involvement of lungs, kidney, oesophagus and bicytopenia thus pointing towards CMV syndrome with end organ damage

1271: MUCINOUS ADENOCARCINOMA MIMICKING INTERSTITIAL LUNG DISEASE DISCOVERED POST-TRANSPLANT

Introduction: Mucinous adenocarcinomas typically present with cough, dyspnea and pleuritic chest pain. They have a wide range of radiographic appearances including a single nodule, lobar consolidation, or diffuse nodules. These tumors can mimic infectious and non-infectious pulmonary pathologies both clinically and radiographically. We report a rare case of invasive mucinous adenocarcinoma, mimicking interstitial lung disease discovered post bilateral lung transplant. Unfortunately, the diagnosis was made after lung transplantation posing a challenge in the management of immunosuppression in the setting of malignancy. Description: A 47-year old male with no prior medical history initially presented with progressive dyspnea on exertion for several months. Family history was significant for pulmonary fibrosis in his mother. High resolution CT chest showed extensive ground-glass opacification, upper lobe honeycombing, and consolidative changes with air bronchograms in bilateral lower lobes. Autoimmune workup and hypersensitivity pneumonitis panel were negative. Bronchoscopy and multiple sputum cultures were unrevealing. Genetic testing identified a mutation in the SFTPA2 gene, associated with familial pulmonary fibrosis. Patient’s respiratory status improved with intravenous steroids and he was discharged with oxygen supplementation, prednisone and nintedanib. However, patient was admitted two months later with clinical deterioration and acute hypoxemic respiratory failure requiring venovenous extracorporeal membrane oxygenation as a bridge to successful bilateral lung transplantation. A lung biopsy prior to transplant could not be obtained given the rapid progression of patient’s respiratory failure. Subsequently, pathology of the explanted lungs showed invasive mucinous adenocarcinoma with metastatic disease to a perihilar lymph node. PET CT scan was negative for extra thoracic metastasis. Discussion: After a multidisciplinary discussion, it was decided to continue immunosuppression with tacrolimus and a decreased dose of mycophenolate. Additionally, active surveillance with PET CT scans every three months was recommended. This case highlights the difficulties faced in the diagnosis of pulmonary adenocarcinoma due to its clinical and radiographic overlap with interstitial lung disease.

402: FATAL TICK BITE

Introduction: As of 2022, there has been no fatality reported in NJ from severe Babesiosis. We present a case of Babesiosis with rapid clinical deterioration to shock and death in an immunocompetent patient despite early recognition and proper recommended treatment through multidisciplinary approach. Description: 48-year-old obese male with Diabetes Mellitus and Hypertension presented to emergency department two weeks after hiking, with epigastric, non-radiating pain associated with fevers, headache, worsening fatigue, poor intake, and watery diarrhea for a week. Patient was febrile, tachypneic, hypoxic, and jaundiced. Initial bloodwork reflected leukocytosis, anemia, elevated reticulocyte count, thrombocytopenia, elevated indirect bilirubinemia, acute kidney Injury and lactic acidosis. Chest radiograph with bilateral lower lobe infiltrates. Babesia microti IgG and IgM were detected with intra and extra cellular paracitemia of 9.9%. Patient was admitted to intensive care unit for Acute respiratory, renal and liver failure. Initially started on Intravenous Azithromycin, Atovaquone and later Doxycycline and Zosyn were added given continued deterioration. Patient required mechanical ventilation and hemodialysis, steroids, Intravenous immunoglobulin. Red blood exchange therapy was completed within 12 hours of admission given high parasitemia. Despite aggressive measures during ICU stay, patient declined and expired 72 hours into hospital course. Discussion: Babesia are intraerythrocytic protozoan parasites of animals and humans, a disease transmitted by infected tick, Ixodes scapularis, which also transmits other causative agents of Lyme Disease. Babesiosis can range from mild to severe disease and death. Severity depends on babesia species, age, host immune status, route of transmission, and parasitemia level. Incidence is highest in summer months, middle-aged patients. Fatality rate reported at 3-9% in hospitalized patients, 20% among immunosuppressed or disease acquisition via blood transfusion. Clinicians need to be aware of the risk of fulminant illness when practicing in known endemic regions. It is important to keep zoonotic infections as part of differential in patient presenting with multi organ failure.

Outcome and growth of lobar graft after pediatric living-donor lobar lung transplantation

Living-donor lobar lung transplantation (LDLLT) remains a life-saving option for pediatric patients with respiratory failure. However, the long-term survival and post-transplant quality of adult lobar grafts transplanted into children are unknown. Therefore, this study aimed to evaluate the outcomes of pediatric LDLLT and post-transplant graft growth. We retrospectively reviewed the prospectively collected clinical data of 25 living-donor lung transplantations performed in 24 pediatric recipients aged ≤17 years. The annual pulmonary function test data and computed tomography scans of 12 recipients, followed up for >5 years without significant complications, were used to evaluate growth in height, graft function, and radiological changes. The Kaplan-Meier method and simple linear regression were performed for analysis. Bilateral lower lobe transplantation was performed in 12 patients, unilateral lower lobe transplantation in 12, and bilateral middle lobe transplantation in 1. The median volumetric size matching at transplantation was 142% (range, 54%-457%). The 5- and 10-year overall survival rates were 87.7% and 75.1༅, respectively. Chronic lung allograft dysfunction occurred in 2 patients. During a median follow-up of 6 years, the median increases in height and vital capacity were 14.4% (range, 0.80%-43.5%) and 58.5% (range, 6.7%-322%), respectively. Graft weight was positively correlated with graft volume (r2=0.622, p<0.001) after the graft volume exceeded the original lobar volume in the donor. This study shows that pediatric LDLLT offers satisfactory long-term survival, with the growth of mature adult lobes transplanted into growing children.

Abstract 12175: A Migrated External Iliac Stent - To Retrieve or Not to Retrieve

Endovascular venous stenting has become a more favorable intervention for occlusive, symptomatic deep vein thromboses (DVTs), especially given its decreased complication rate and shorter recovery time than its predecessor, open venous bypass. Risks, however, still exist and can include stent fragmentation and dislodgement causing cardiopulmonary complications. A 57-year-old man with bilateral lower extremity DVTs status post left external ilio-femoral stent and inferior vena cava (IVC) filter placement presented with one month of atypical chest discomfort. CT chest showed migration of his 40cm iliac stent to the IVC and right atrium. Interventional radiology visualized both a patent stent and IVC, however, attempted endovascular removal from the distal margin failed with initial retrieval of fragments only. Other fragments subsequently embolized to the pulmonary and lower lobe arteries and right ventricles. Extraction of more distal fragments was deferred due to risks of structural damage, arrhythmias, and pulmonary vasculature perforation. Fragment analysis by pathology demonstrated evidence of clot, yet cardiothoracic surgical intervention was deferred.The patient continued to experience chest pain and underwent a repeat CT chest three months later that demonstrated the stent extending from the right atrial junction to the infrahepatic IVC. Fragmented portions of the filter in the right ventricle and multiple stent fragments retained in the right upper and bilateral lower pulmonary lobes remained as prior with no evidence of pulmonary embolism (PE), pericardial effusion, or tamponade. Although rare, stent removal complications can occur with increased risk of long-term sequelae. Stent fracturing and dislodgement can result in foreign bodies showering the pulmonary vasculature and cardiac chambers, ultimately placing patients at risk for arterial perforation or dissection, pulmonary hemorrhage, intracardiac damage, tamponade, PE, and chronic thromboembolic pulmonary hypertension (CTEPH). The consideration of such risks, in addition to early involvement of interdisciplinary teams and thorough risk-benefit discussions between patients and providers are essential when undergoing stent removal and related interventions.

ODP390 Metastatic Gestational Trophoblastic Neoplasia Masquerading as Thyroid Storm in a Girl with Molar Pregnancy and Hyperthyroidism

Abstract The Case Patient is a 16-year-old female with molar pregnancy, admitted for D&amp;C, referred for hyperthyroidism, concern for thyroid storm. A month prior, she presented with heavy vaginal bleeding, morning sickness. Ultrasound showed blighted ovum. HCG was significantly elevated, 668,123 mIU/mL. TSH was low at 0. 01 mIU/L, Free T4 elevated 2.3 ng/dL. No family history of thyroid dysfunction. She was for was noted to have respiratory distress, hypoxia, and tachycardia in the 120s post-operatively. LFTs normal, no fever, jaundice or CNS manifestations. Chest CT showed bilateral lower lobe localized pulmonary edema concerning for trophoblastic fluid embolism vs thyroid storm. BWPS = 40. She was placed on PTU, beta blockade, Lugol's iodine, and hydrocortisone. Repeat chest CT showed diffuse pulmonary nodules consistent with gestational trophoblastic neoplasm (GTN). No other metastasis on further imaging (chest, abdomen, pelvis, brain). Clinical status improved, FT4 normalized 5 days after starting treatment. TRAbs negative. She was discharged on Methimazole and Atenolol, which were eventually discontinued. HCG levels significantly decreased after D&amp;C but remained detectable on follow-up. Endocervix/uterine curettage showed intraplacental choriocarcinoma arising within a complete hydatidiform mole. She is followed by Oncology and currently undergoing chemotherapy. Discussion HCG-mediated hyperthyroidism include gestational transient thyrotoxicosis, hyperemesis gravidarum, and trophoblastic hyperthyroidism (TH). Due to significant homology between TSH and the beta-subunit of HCG, HCG can cause hyperthyroidism. 2-60% of women with trophoblastic disease may have symptomatic hyperthyroidism at time of diagnosis which can be severe. Patients with GTN (choriocarcinoma in our case) have a higher likelihood of TH, as HCG exceeds 100,000 mIU/mL. Choriocarcinoma is the most aggressive type of GTN characterized by vascular invasion and widespread metastases, of which the most common sites are vagina and lungs. Patients with pulmonary metastasis my present with respiratory distress, chest pain, cough or hemoptysis. Our patient was initially thought to have impending thyroid storm mainly from findings of pulmonary edema, respiratory distress, tachycardia, and precipitant history (D&amp;C), and was managed as such while further workup was being undertaken. Realization that the initial chest CT findings of pulmonary edema were actually related to multiple pulmonary nodules and GTN made thyroid storm less likely. Hyperthyroidism typically resolves with decreasing HCG levels in TH. Indeed, our patient no longer needed ATD once her HCG levels subsided s/p D&amp;C. Conclusion One of the most common sites of metastasis in GTN is the lungs. An acute presentation of respiratory distress and pulmonary findings on chest imaging upon simultaneous discovery of TH may complicate management as thyroid storm needs to be considered. Although a higher index of suspicion for metastatic GTN should be made in this situation, a conservative management approach of treating for possible impending thyroid storm until definitive diagnosis has been established is prudent. Presentation: No date and time listed

WHEN LUNG BECOMES BONE: A RARE CASE OF DENDRIFORM PULMONARY OSSIFICATION

WHEN LUNG BECOMES BONE: A RARE CASE OF DENDRIFORM PULMONARY OSSIFICATION

Dynamic chest computed tomography change analysis and prediction of length of stay for delta variant COVID-19 patients

OBJECTIVE: As hospital admission rate is high during the COVID-19 pandemic, hospital length of stay (LOS) is a key indicator of medical resource allocation. This study aimed to elucidate specific dynamic longitudinal computed tomography (CT) imaging changes for patients with COVID-19 over in-hospital and predict individual LOS of COVID-19 patients with Delta variant of SARS-CoV-2 using the machine learning method. MATERIALS AND METHODS: This retrospective study recruited 448 COVID-19 patients with a total of 1761 CT scans from July 14, 2021 to August 20, 2021 with an averaged hospital LOS of 22.5 ± 7.0 days. Imaging features were extracted from each CT scan, including CT morphological characteristics and artificial intelligence (AI) extracted features. Clinical features were obtained from each patient's initial admission. The infection distribution in lung fields and progression pattern tendency was analyzed. Then, to construct a model to predict patient LOS, each CT scan was considered as an independent sample to predict the LOS from the current CT scan time point to hospital discharge combining with the patients' corresponding clinical features. The 1761 follow-up CT data were randomly split into training set and testing set with a ratio of 7:3 at patient-level. A total of 85 most related clinical and imaging features selected by Least Absolute Shrinkage and Selection Operator were used to construct LOS prediction model. RESULTS: Infection-related features were obtained, such as the percentage of the infected region of lung, ground-glass opacity (GGO), consolidation and crazy-paving pattern, and air bronchograms. Their longitudinal changes show that the progression changes significantly in the earlier stages (0–3 days to 4–6 days), and then, changes tend to be statistically subtle, except for the intensity range between (−470 and −70) HU which exhibits a significant increase followed by a continuous significant decrease. Furthermore, the bilateral lower lobes, especially the right lower lobe, present more severe. Compared with other models, combining the clinical, imaging reading, and AI features to build the LOS prediction model achieved the highest R 2 of 0.854 and 0.463, Pearson correlation coefficient of 0.939 and 0.696, and lowest mean absolute error of 2.405 and 4.426, and mean squared error of 9.176 and 34.728 on the training and testing set. CONCLUSION: The most obvious progression changes were significantly in the earlier stages (0–3 days to 4–6 days) and the bilateral lower lobes, especially the right lower lobe. GGO, consolidation, and crazy-paving pattern and air bronchograms are the most main CT findings according to the longitudinal changes of infection-related features with LOS (day). The LOS prediction model of combining clinical, imaging reading, and AI features achieved optimum performance.

RAPIDLY PROGRESSING DERMATOMYOSITIS-ASSOCIATED RESPIRATORY FAILURE SUCCESSFULLY STABILIZED WITH EXTRACORPOREAL MEMBRANE OXYGENATION

RAPIDLY PROGRESSING DERMATOMYOSITIS-ASSOCIATED RESPIRATORY FAILURE SUCCESSFULLY STABILIZED WITH EXTRACORPOREAL MEMBRANE OXYGENATION

GOING WITH THE FLOW: A UNIQUE PRESENTATION OF EISENMENGER SYNDROME

GOING WITH THE FLOW: A UNIQUE PRESENTATION OF EISENMENGER SYNDROME

MALPOSITION OF RIGHT INTERNAL JUGULAR VEIN CATHETER IN RIGHT AXILLARY VEIN: A RARE CASE DIAGNOSED BY BEDSIDE ULTRASOUND

MALPOSITION OF RIGHT INTERNAL JUGULAR VEIN CATHETER IN RIGHT AXILLARY VEIN: A RARE CASE DIAGNOSED BY BEDSIDE ULTRASOUND

AN UNCOMMON PRESENTATION OF ANTISYNTHETASE SYNDROME-RELATED INTERSTITIAL LUNG DISEASE IN A YOUNG INDIAN MALE

AN UNCOMMON PRESENTATION OF ANTISYNTHETASE SYNDROME-RELATED INTERSTITIAL LUNG DISEASE IN A YOUNG INDIAN MALE

71-Year-Old Man With a New Heart Murmur

71-Year-Old Man With a New Heart Murmur

Recurrent syncope with hyponatremia as presentation of COVID-19 viral pneumonia

Syncope is the most common neurological presentation in intensive care setting and has diverse etiological factors ranging from ischemic and nonischemic neurovascular, cardiac dysfunction related, infectious, electrolyte imbalance, inflammatory factors to simple viral fever, and other system-related illnesses. Coronavirus disease-19 (COVID-19) is known to cause pulmonary and extrapulmonary complications including effects on cardiovascular, gastrointestinal, renal, and neurovascular systems. In this case report, we have documented a 70-year-old male presented with recurrent syncope with flu-like illness, HRCT thorax suggestive of pneumonia involving bilateral lower lobe, COVID-19 real-time polymerase chain reaction (RT-PCR) positive, with abnormal laboratory parameters such as platelet count, CRP, serum sodium, and vitamin B12 level. Further investigations such as echocardiography, MRI brain and MRI angiography, and carotid Doppler were inconclusive. We have observed excellent clinical and radiological response to steroids, anticoagulants, antiplatelets, and remdesivir with other supportive care in critical care unit.

High-grade endometrial stromal sarcoma: A case report

Background: High-grade endometrial stromal sarcoma (HG-ESS) is a homologous uterine sarcoma of a mesenchymal origin. Its natural course is poorly understood, making preoperative diagnosis difficult.&#x0D; Case presentation: A 55-year-old nulliparous presented to the gynecological oncology ward as a referral with progressive abdominal distension and pain, constipation, and postprandial vomiting. Computed tomography (CT) scan of the abdomen revealed a bulky uterus with multiple calcified masses with cystic degeneration. A chest CT scan revealed bilateral upper and lower lobe nodules with mediastinum and hilar adenopathy. She was scheduled for total abdominal hysterectomy and bilateral salpingo-oophorectomy. A histopathological examination confirmed HG-ESS. The patient survived for three months following surgery.&#x0D; Conclusion: HG-ESS is rare. This case highlights the nonspecific presentation, aggressive nature of the tumor, rapid progression of the disease, and the challenges clinicians face in managing patients who do not honor their appointments with resultant poor overall survival in the late stage.

Peripartum Severe COVID-19 Pneumonia: Fetal and Neonatal Implications.

Peripartum Severe COVID-19 Pneumonia: Fetal and Neonatal Implications.

Unilateral vs Bilateral Lower Lobe Surveillance Transbronchial Biopsies in Patients with Bilateral Lung Transplant Patients

<h3>Purpose</h3> Transbronchial biopsies are routinely performed in surveillance of subclinical rejection after lung transplantation. Sensitivity of transbronchial biopsies can be increased by sampling lower lobes and multiple lobes. Due to the inherent risks of the procedure, biopsies are usually limited to one lung. It is not known if sampling bilateral lower lobes improves diagnostic sensitivity for ACR or affects the outcomes. At our institution, one of the transplant pulmonologist routinely biopsies both the lower lobes hence, this provided us with an opportunity to study and compare the diagnostic yield of biopsies of unilateral vs bilateral lower lobes. <h3>Methods</h3> Retrospective analysis of charts was performed on 83 patients transplanted with lungs bilaterally over 3.5 years. Details of surveillance transbronchial biopsies at 1, 3, 6, 9 (Optional) and 12 months after transplantation were collected for analysis. <h3>Results</h3> 83 lung transplant recipients studied over 3.5 years with a total of 427 transbronchial biopsies. Out of these, 116 procedures were performed bilaterally and 195 procedures were performed unilaterally. Among the 116 patients biopsied bilaterally, 2 samples were inadequate and 25 patients (21.73%) had evidence of ACR including minimal (A1) in 31 samples and A2 rejection in 1 sample. Only 6 out of 25 patients had evidence of ACR in both the lower lobes and 4 out of those procedures were performed in the same patient at different times. Only one of these patient with A2 rejection and another with persistent A1 rejection were treated with pulsed dose steroids for ACR. Among the 195 samples obtained unilaterally, 1 sample was inadequate and 30 biopsy specimens had evidence of ACR (15.38%) including minimal (A1) ACR in 24 samples and mild (A2) rejection in 6 samples. All patients with A2 rejection were treated with pulsed dose steroids for ACR. There were no reported episodes of life threatening hemoptysis or pneumothorax associated any of the above procedures. <h3>Conclusion</h3> In bilateral lung transplant recipients, bilateral lower lobe surveillance transbronchial biopsies may increase the yield for detection of ACR. Detection of ACR simultaneously in both the lower lobes is rare. Unilateral ACR was minimal in most of the biopsies and did not alter the management. Bilateral lower lobe biopsies was not associated with increased risk of pneumothorax

Relapsed Nocardiosis Presenting as Acute Vision Loss

<h3>Introduction</h3> Opportunistic infections with Nocardia spp. can be morbid in lung transplant recipients (LTxRs). Nocardia is most commonly acquired by inhalation, and most patients present with respiratory involvement. Treatment strategies vary, but typically include 2 antimicrobials initially, followed by a prolonged course with a single agent. Although treatment is often curative, relapses can occur. We describe a case of relapsed nocardiosis presenting with acute vision loss in an LTxR. <h3>Case Report</h3> A 68-year-old woman presented with a left lower lobe mass-like consolidation 7 months after bilateral LTx for sarcoidosis. <i>Nocardia cyriacigeogica</i> was isolated from bronchoalveolar lavage (BAL) and she was treated with ceftriaxone (CTX), linezolid, and inhaled amikacin. Trimethoprim-sulfamethoxazole (TMX-SM) was not administered due to a history of hives with sulfa derivatives. Brain MRI and abdomen/pelvis CT showed no evidence of disseminated disease. Her antimicrobials were changed to CTX, minocycline, and inhaled amikacin based on sensitivities, and she completed a 6-month course with radiographic improvement and 2 negative BAL cultures. Six months after stopping nocardia-directed treatment, she presented with left-sided vision loss. MRI of the orbits revealed soft tissue thickening in the posterior left globe, and brain MRI showed rim enhancing lesions in the right frontal lobe. CT of the chest, abdomen, and pelvis showed a slight interval worsening of multifocal tree-in-bud nodules in bilateral lower lobes of the lungs, but no evidence of abdominopelvic infection, and BAL grew acremonium spp. Retinal exam showed vitritis and retinal detachment. She was treated with intravitreal amikacin and was restarted on systemic CTX and linezolid for presumed Nocardia relapse. A trial of TMX-SM showed no evidence of drug allergy, thus CTX and linezolid were replaced with TMX-SM—2 DS tablets BID. After a year, the TMX-SM dose was reduced to 1 DS tablet BID to refractory leukopenia and hyperkalemia. Nearly 3 years after relapse, she remains on this regimen with no evidence of recurrent disease or drug intolerance and resolution of vision loss and MRI abnormalities. <h3>Summary</h3> Nocardiosis can relapse despite prolonged antimicrobial therapy, particularly in immunocompromised patients, and clinical presentation can be extra-pulmonary. Ongoing administration of TMX-SM may prevent relapse in high-risk patients.

Clinical characteristics of plastic bronchitis in children: a retrospective analysis of 43 cases

BackgroundWith an increase in the diagnosis of plastic bronchitis (PB) cases, to enhance paediatricians’ knowledge and add to the few existing studies, we explored the clinical characteristics, diagnosis, and treatment of PB in children.MethodsThe clinicopathological data of 43 children admitted to the Xiamen Children’s Hospital and the Women and Children’s Hospital, affiliated to the Xiamen University from December 2016 to December 2019, were retrospectively analysed.ResultsAll the children had cough, with 41 of them having associated fever. A peak temperature > 40 ℃ was observed in 25 children. Twenty-six children had shortness of breath, 27 had reduced respiratory sounds on the affected side, and 35 had audible moist rales on the affected side. Lactate dehydrogenase in all children increased to different degrees, and 29 had elevated D-dimer and fibrinogen degradation products. Lung imaging showed pulmonary consolidation and atelectasis, mainly in the bilateral lower lung lobes, in all the children. However, 31 had pleural effusion, mainly a small parapneumonic effusion. The infections were mainly caused by adenovirus and Mycoplasma pneumoniae. The casts in all 43 children were sucked or clamped out under bronchoscopy, and 10 were found to have type I PB on pathological examination. All children were treated with anti-infective therapy in addition to bronchoscopic cast removal. Thirty-one children were treated with methylprednisolone, and 16 with gamma globulin. Except for one child who was non-adherent to treatment, all other children showed improvement, or were cured and discharged from the hospital. Follow-up lung imaging at 3 months revealed that the lungs were fully re-expanded in 40 children. At the 6-month follow-up, six children had small airway lesions, four had obliterative bronchiolitis, and one had bronchiectasis.ConclusionsPaediatric PB often occurs secondary to respiratory tract infections and progresses rapidly, with hyperpyrexia, cough, and shortness of breath as the main clinical manifestations. Pulmonary consolidation, atelectasis, and pleural effusion are seen on lung imaging, and early bronchoscopy and removal of casts in the trachea and bronchi are effective treatment options.

Asynchronous changes of normal lung lobes during respiration based on quantitative computed tomography (CT).

This study aimed to explore the coordinated and independent actions of lung lobes during respiration using quantitative computed tomography (CT) in order to increase our in vivo understanding of pulmonary anatomy. Cases for whom test results showed normal pulmonary function tests (PFTs) results, and normal paired inspiratory-expiratory chest CT findings, as assessed by 2 radiologists, were retrospectively included in this study. From the chest CT results, we measured quantitative indices of lung volume (LV) and mean lung density (MLD) for the total lung (TL), left lung (LL), right lung (RL), and 5 lobes in inspiratory and expiratory phases. The differences of these measures between bilateral lungs and among the lobes were evaluated to study whether they were consistent or different during respiration. A total of 70 cases were included {median age of 49.5 [interquartile range (IQR), 38.0 to 60.3] years; 32 males; 38 females}. Overall, the inspiratory and expiratory volumes of the LL were smaller than those of the RL (both P<0.001). For the ventilation workload (λ, which indicates the ratio of lobar volume to total LV), the end-expiratory volume ratio (λex ) of the LL was 0.44 (IQR, 0.43 to 0.46), while the end-inspiratory volume ratio (λin ) had risen to 0.46 (IQR, 0.45 to 0.47) (P<0.001). Comparing the 5 lobes, not all lobes shared the same LV. However, the left lower lobe (LLL) and right lower lobe (RLL) showed some similarities. The λin-LLL and λin-RLL was higher than λex-LLL and λex-RLL , respectively (both P<0.001), while the ratios of the other lobes reduced. The pairwise mean absolute difference (PMAD) on λin and λex of the bilateral lower lobes was low in inspiration (0.0288) and expiration (0.0346). The MLD of bilateral lower lobes showed consistency in inspiration or in expiration (inspiration: P>0.999; expiration: P=0.975). In addition, the PMADs between the right middle lobe (RML) and other lobes were significantly larger than the PMAD between other pairs of lobes in both inspiration and expiration. Beyond that, the expiratory MLD of RML [-789.6 (IQR, -814 to -762.05) HU] was the lowest among the 5 lobes. We found that the LL assumes a higher workload during ventilation than it does during respiration. The 5 normal lobes were non-synchronous during respiration and contributed differently to ventilation. The bilateral lower lobes showed similarities and had a high-ventilation function, while and the LV and MLD of the RML showed the least changes within a respiration cycle.