Diagnostic yield of flexible bronchoscopy for immunocompromised patients with lung infiltrates: A single-center, retrospective study.

BACKGROUND: Pulmonary complications are associated with mortality in immunocompromised patients. The usefulness of bronchoscopy has been reported. However, clinical factors and procedures that influence diagnostic yield are still not established. MATERIALS AND METHODS: We retrospectively analyzed 115 bronchoscopies performed on 108 immunocompromised patients, defined as those who take corticosteroids and/or immunosuppressants. We evaluated clinical factors, sampling procedures, final diagnosis, and severe complications of bronchoscopy. RESULTS: The clinical diagnosis was obtained in 51 patients (44%). Of those, 33 cases were diagnosed as infectious diseases and 18 as non-infectious diseases. Nine out of 115 cases (7.8%) initiated new immunosuppressive treatment for an underlying disorder based on the negative microbiological results obtained with bronchoscopy. Collagen vascular disease was the most common underlying disorders (62 patients, 54%). Bronchoscopy was useful regardless of whether the patient was immunosuppressed to treat collagen vascular disease (P = 0.47). Performing transbronchial biopsy correlated with better diagnostic yield of bronchoscopy (54.7% vs 35.5%, P = 0.049). Other clinical factors, such as radiological findings, respiratory failure or antibiotic use at the time of bronchoscopy did not significantly influence diagnostic yield. Respiratory failure requiring intubation after bronchoscopy occurred only in one case (0.9%). CONCLUSIONS: Our study implied the transbronchial biopsy may be a useful procedure for reaching a diagnosis in immunocompromised patients with pulmonary infiltrates. In addition, our data suggest the usefulness of bronchoscopy for immunocompromised patients due to the treatment of collagen vascular disease as well as other underlying disorders.

Prospective Randomized Controlled Trial Comparing Anesthetic Management With Remimazolam Besylate and Flumazenil Versus Propofol During Awake Craniotomy Following an Asleep-awake-asleep Method.

BACKGROUND: Awake craniotomy is performed to resect brain tumors in eloquent brain areas to maximize tumor reduction and minimize neurological damage. Evidence suggests that intraoperative anesthetic management of awake craniotomy with remimazolam is safe. We compared the time to arousal and efficacy of anesthetic management with remimazolam and propofol during awake craniotomy. METHODS: In a single-institution randomized, prospective study, patients who underwent elective awake craniotomy were randomized to receive remimazolam and reversal with flumazenil (group R) or propofol (group P). The primary end point was time to awaken. Secondary end points were time to loss of consciousness during induction of anesthesia, the frequency of intraoperative complications (pain, hypertension, seizures, nausea, vomiting, and delayed arousal), and postoperative nausea and vomiting. Intraoperative task performance was assessed using a numerical rating scale (NRS) score. RESULTS: Fifty-eight patients were recruited, of which 52 (26 in each group) were available for the efficacy analysis. Patients in group R had faster mean (±SD) arousal times than those in the P group (890.8±239.8 vs. 1075.4±317.5 s; P=0.013)and higher and more reliable intraoperative task performance (NRS score 8.81±1.50 vs. 7.69±2.36; P=0.043). There were no significant intraoperative complications. CONCLUSIONS: Compared with propofol, remimazolam was associated with more rapid loss of consciousness and, after administration of flumazenil, with faster arousal times and improved intraoperative task performance.

Evaluation of the accuracy of ChatGPT's responses to and references for clinical questions in physical therapy.

[Purpose] This study evaluated the accuracy of ChatGPT's responses to and references for five clinical questions in physical therapy based on the Physical Therapy Guidelines and assessed this language model's potential as a tool for supporting clinical decision-making in the rehabilitation field. [Participants and Methods] Five clinical questions from the "Stroke", "Musculoskeletal disorders", and "Internal disorders" sections of the Physical Therapy Guidelines, released by the Japanese Society of Physical Therapy, were presented to ChatGPT. ChatGPT was instructed to provide responses in Japanese accompanied by references such as PubMed IDs or digital object identifiers. The accuracy of the generated content and references was evaluated by two assessors with expertise in their respective sections by using a 4-point scale, and comments were provided for point deductions. The inter-rater agreement was evaluated using weighted kappa coefficients. [Results] ChatGPT demonstrated adequate accuracy in generating content for clinical questions in physical therapy. However, the accuracy of the references was poor, with a significant number of references being non-existent or misinterpreted. [Conclusion] ChatGPT has limitations in reference selection and reliability. While ChatGPT can offer accurate responses to clinical questions in physical therapy, it should be used with caution because it is not a completely reliable model.

NECTIN2 is a prognostic biomarker and potential therapeutic target in lung adenocarcinoma.

INTRODUCTION: NECTINs are transmembrane proteins mediating cell-to-cell adhesion. NECTINs interact with integrins or other membrane receptors to trigger multiple cellular functions. Aberrant NECTIN expression is associated with cancer progression and poor outcomes. While NECTIN2 is overexpressed in various cancer types, its role in lung cancer is not well understood. MATERIAL AND METHODS: We investigated the function of NECTIN2 in lung adenocarcinoma (LUAD) using the Cancer Genome Atlas (TCGA) dataset and clinical samples of 105 LUAD patients who had undergone surgical resection. Cell proliferation, apoptosis, migration and invasion were investigated using human lung adenocarcinoma cell lines. RESULTS: We found that high NECTIN2 expression correlated with reduced overall survival in LUAD in TCGA database. In clinical samples, high NECTIN2 expression was associated with lower recurrence-free survival in all patients (P < 0.001) and in stage I patients (P = 0.001). Functional analyses demonstrated that NECTIN2 knockout promoted cell apoptosis and diminished cell proliferation and migration capacity. NECTIN2 overexpression did not significantly affect cellular functions. DISCUSSION: Our results suggest that NECTIN2 plays a significant role in cell apoptosis and cancer cell migration, leading to increased postoperative recurrence. Furthermore, NECTIN2 serves as a prognostic indicator and a potential therapeutic target in LUAD. CONCLUSIONS: High NECTIN2 expression in LUAD was found to be associated with postoperative recurrence, and was observed to play an important role in cell apoptosis and migration.

Improvement of limit of detection in primer extension-based multiplexed mutation assay using capillary electrophoresis.

One of the challenges in liquid biopsy for early cancer detection is ascribed to the fact that mutation DNA often represents an extremely small ratio of less than 1% compared to wild-type genes in blood. However, in conventional fragment analysis with capillary electrophoresis (CE), the detectable allele frequency could be about 5%. In this work, we developed an original reagent-based fragment analysis with single base extension (SBE) reactions for cancer-associated mutation assay using a commercially available CE device, and investigated on a possibility of improvement of limit of detection (LOD) for genetic mutation. First, after adjustment of reagent conditions for the SBE reactions, the linear relationship between gene template concentration and fluorescence intensity was obtained from 1 to 100 fmol of target genes. Next, from the results of an experiment to detect mutation EGFR L858R at abundance ratios of mutant type to wild type (100-fmol template) of 0, 1, 5, and 10%, it was shown that the target gene can be detected with LOD of 0.33%. This high sensitivity was realized in part by separating fluorescently labeled substrates into an individual tube for an each-colored SBE reaction. Moreover, mutations EGFR L858R and KRAS G12V were simultaneously detected at sensitivities equivalent to LODs of 0.57 and 0.47%, respectively. These results indicate that < 1% of mutations in multiplex gene mutations can be simultaneously detected, and that possibility suggests that the developed method can be used in clinical practice for detecting cancers.

Impairment of Social-Related Quality of Life in COVID-19 Pneumonia Survivors: A Prospective Longitudinal Study.

The post-acute sequelae of SARS-CoV-2 (PASC) pose a threat to patients' health-related quality of life (HRQOL). Here, the impact of COVID-19 on HRQOL and the clinical factors associated with impaired HRQOL were examined. Discharged COVID-19 patients were assessed at 3 and 6 months after disease onset. The patients completed a medical examination and the SF-36 questionnaire at these two time points and underwent pulmonary function testing at 6 months after disease onset. All had undergone computed tomography (CT) imaging upon hospital admission. Of the 74 included patients, 38% reported respiratory symptoms at 3 months, and 26% reported respiratory symptoms at 6 months after disease onset. The aggregated SF-36 scores declined in the role/social component summary (RCS), a category related to social activity. Patients with lower RCS tended to have respiratory sequelae or a relatively lower forced vital capacity. The CT score that reflected the extent of COVID-19 pneumonia was inversely correlated with the RCS score (3 months, p = 0.0024; 6 months, p = 0.0464). A high CT score (≥10 points) predicted a low RCS score at 6 months (p = 0.013). This study highlights the impairment of RCS and its associations with respiratory sequelae. The study also emphasizes the importance of radiological findings in predicting long-term HRQOL outcomes after COVID-19.

Cancer of unknown primary histologically, genetically and spatially diagnosed as left ovary­derived cancer: A case report.

Cancer of unknown primary (CUP) is a heterogeneous syndrome of metastatic cancer in which the primary site cannot be determined even after a standard and comprehensive search. The present report describes a case in which the spatial distribution of the lymph node metastases contributed to the identification of the primary site. While the standard workup did not identify the primary tumor, genomic profiling analysis was useful in therapeutic management. A 68-year-old woman presented with a cancerous pleural effusion (adenocarcinoma). The primary site could not be identified, and the pleural effusion resolved spontaneously. After 11 months, the patient had elevated Krebs von den Lungen-6 and cancer antigen 125 levels, and multiple enlarged lymph nodes. Pathological diagnosis based on a biopsy sample of the para-aortic lymph nodes indicated that the tumor was a high-grade serous carcinoma of possible gynecological organ origin. The patient underwent surgery, including hysterectomy, bisalpingo-oophorectomy and lymph node dissection. Although there were no primary sites in the gynecological organs, marked lymphovascular invasion was found around the left ovary, suggesting a left ovary-derived tumor. Genetic testing revealed a high loss of heterozygosity score and high tumor mutational burden (TMB). The patient received paclitaxel and carboplatin therapy followed by a poly ADP-ribose polymerase inhibitor as regimens for ovarian cancer and achieved complete remission. The unique course of the disappearance of the effusion and the absence of tumor in the adnexa might be associated with the high immunogenicity of the tumor characterized by the high TMB. This case may provide insights into the pathogenesis of CUP.

Validity of diagnoses of respiratory diseases recorded in a Japanese administrative database.

BACKGROUND: Validating the information recorded in administrative databases is essential. However, no study has comprehensively validated the accuracy of Japanese Diagnosis Procedure Combination (DPC) data on various respiratory diseases. Therefore, this study aimed to evaluate the validity of diagnoses of respiratory diseases in the DPC database. METHODS: We conducted chart reviews of 400 patients hospitalized in the departments of respiratory medicine in two acute-care hospitals in Tokyo, between April 1, 2019 and March 31, 2021, and used them as reference standards. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of DPC data on 25 respiratory diseases were determined. RESULTS: Sensitivity ranged from 22.2% (aspiration pneumonia) to 100% (chronic eosinophilic pneumonia and malignant pleural mesothelioma) and was <50% for eight diseases, while specificity was >90% for all diseases. PPV ranged from 40.0% (aspiration pneumonia) to 100% (coronavirus disease 2019, bronchiectasis, chronic eosinophilic pneumonia, pulmonary hypertension, squamous cell carcinoma, small cell carcinoma, lung cancer of other histological types, and malignant pleural mesothelioma) and was >80% for 16 diseases. Except for chronic obstructive pulmonary disease (82.9%) and interstitial pneumonia (other than idiopathic pulmonary fibrosis) (85.4%), NPV was >90% for all diseases. These validity indices were similar in both hospitals. CONCLUSIONS: The validity of diagnoses of respiratory diseases in the DPC database was high in general, thereby providing an important basis for future studies.

Palladium-catalyzed addition of acylsilanes across alkynes via the activation of a C-Si bond.

Palladium-catalyzed addition of a C-Si bond in acylsilanes across the triple bonds in an alkyne bearing a carbonyl group at one terminal is reported. The reaction proceeds with excellent regioselectivity, in which a silyl group is incorporated into the carbon α to the carbonyl group, allowing for straightforward access to a variety of functionalized alkenylsilane derivatives. Catalytic synthesis of indanones by annulation between acylsilanes and alkynes with an identical catalytic system is also reported.

Integrin alpha 2 is associated with tumor progression and postoperative recurrence in non-small cell lung cancer.

BACKGROUND: Integrins are transmembrane proteins that mediate cell adhesion to extracellular matrix. Whereas expression of integrin alpha 2 is associated with motility, invasiveness and cellular differentiation in various tumors, the role of integrin alpha 2 in lung cancer has not been studied in detail. The aim of this study was to determine whether and how aberrant integrin alpha 2 expression in non-small cell lung cancer leads to different outcomes. METHODS: We measured expression of integrin alpha 2 by quantitative polymerase chain reaction in 100 samples collected from non-small cell lung cancer patients who had undergone surgical resection. We assigned patients to high and low expression groups and analyzed survival. Cellular morphology, adhesion, proliferation, migration and invasion were examined in human lung cancer cell lines. RESULTS: Among 100 cases, 41 were female, with a median age of 71 years. High expression of integrin alpha 2 in non-small cell lung cancer was associated with lower recurrence-free survival (P = 0.004). Overexpression of integrin alpha 2 in cell lines had no effect on cell proliferation or invasion but resulted in increased cell size (1416 µm2 versus 470 µm2 in H522 cells, P < 0.001; 1822 µm2 versus 1029 µm2 in H661 cells, P = 0.02), adhesion (P < 0.001 in H522 and H661 cells) and migration (gap area filled was 71% versus 36% in H522 cells, P < 0.001; 57% versus 26% in H661 cells, P = 0.001). These changes were suppressed by E7820, an inhibitor of integrin alpha 2. CONCLUSIONS: Integrin alpha 2 may play a significant role in lung cancer adhesion and migration, and may lead to a higher risk of recurrence.

Measurement of Turbulent Kinetic Energy in Hypertrophic Cardiomyopathy Using Triple-velocity Encoding 4D Flow MR Imaging.

PURPOSE: The turbulent kinetic energy (TKE) estimation based on 4D flow MRI has been currently developed and can be used to estimate the pressure gradient. The objective of this study was to validate the clinical value of 4D flow-based TKE measurement in patients with hypertrophic cardiomyopathy (HCM). METHODS: From April 2018 to March 2019, we recruited 28 patients with HCM. Based on echocardiography, they were divided into obstructed HCM (HOCM) and non-obstructed HCM (HNCM). Triple-velocity encoding 4D flow MRI was performed. The volume-of-interest from the left ventricle to the aortic arch was drawn semi-automatically. We defined peak turbulent kinetic energy (TKEpeak) as the highest TKE phase in all cardiac phases. RESULTS: TKEpeak was significantly higher in HOCM than in HNCM (14.83 ± 3.91 vs. 7.11 ± 3.60 mJ, P < 0.001). TKEpeak was significantly higher in patients with systolic anterior movement (SAM) than in those without SAM (15.60 ± 3.96 vs. 7.44 ± 3.29 mJ, P < 0.001). Left ventricular (LV) mass increased proportionally with TKEpeak (P = 0.012, r = 0.466). When only the asymptomatic patients were extracted, a stronger correlation was observed (P = 0.001, r = 0.842). CONCLUSION: TKE measurement based on 4D flow MRI can detect the flow alteration induced by systolic flow jet and LV outflow tract geometry, such as SAM in patients with HOCM. The elevated TKE is correlated with increasing LV mass. This indicates that increasing cardiac load, by pressure loss due to turbulence, induces progression of LV hypertrophy, which leads to a worse prognosis.

Effect of nintedanib on acute exacerbations of fibrosing interstitial lung diseases: a national database study in Japan.

Background: Acute exacerbation is a life-threatening event in patients with fibrosing interstitial lung diseases (ILDs). Although nintedanib reduces acute exacerbation incidence, its effectiveness during acute exacerbation is unclear. Methods: Using data from the Diagnosis Procedure Combination database (September 2015-March 2020) in Japan, we identified patients with fibrosing ILDs who received intravenous injection of high-dose corticosteroid within 3 days post-admission and analysed their first hospitalisation. We performed overlap propensity score weighting to compare in-hospital outcomes between patients who received nintedanib within 14 days post-admission and those who did not. The primary and secondary outcomes were in-hospital mortality and length of hospitalisation in the patients discharged alive, respectively. Results: Among the 6235 identified patients, 353 patients received nintedanib within 14 days post-admission. In-hospital mortality occurred in 13.7% and 6.0% patients in the control (n=5882) and nintedanib-treated (n=353) patients, respectively. The mean length of hospitalisation was 39.9 and 30.4 days in the control and nintedanib-treated patients, respectively. After overlap propensity score weighting, nintedanib treatment was significantly associated with lower in-hospital mortality in the adjusted cohort (OR 0.43, 95% CI 0.27-0.70; p=0.001). The mean length of hospitalisation in nintedanib-treated patients (30.7 days) was significantly shorter than that in the control group (37.5 days; p<0.001). Conclusions: Nintedanib initiation during acute exacerbation was significantly associated with a lower risk of in-hospital death and shorter length of hospitalisation in patients with fibrosing ILDs. Our results elucidate the potential role of nintedanib in the treatment of acute exacerbation in patients with fibrosing ILDs. Further prospective studies are warranted.

The Feasibility of a Newly Developed Local Network System for Cardiac Rehabilitation (the CR-GNet) in Disease Management and Physical Fitness after Acute Coronary Syndrome.

OBJECTIVE: To examine the Cardiac Rehabilitation Gifu Network (CR-GNet) feasibility in managing diseases and assisting patients in attaining physical fitness, and its impact on long-term outcomes after acute coronary syndrome (ACS). METHODS: In this prospective observational study, we enrolled 47 patients with ACS registered in the CR-GNet between February 2016 and September 2019. 37, 29, and 21 patients underwent follow-up assessments for exercise capacity (peak oxygen uptake) at 3 months, 6 months, and 1 year after discharge, respectively. Major adverse cardiac events (MACE) were compared with controls not registered in the CR-GNet. RESULTS: The coronary risk factors, except blood pressure, improved at 3 and 6 months, and 1 year after discharge. These risk factors in each patient significantly reduced from 2.9 at admission to 1.6, 1.4, and 1.9 at 3 months, 6 months, and 1 year after discharge (p<0.05), respectively. Peak oxygen uptake was significantly higher at 3 months (17.5±4.9 ml/kg/min), 6 months (17.9±5.1 ml/kg/min), and 1 year (17.5±5.5 ml/kg/min) after discharge than that at discharge (14.7±3.6 ml/kg/min) (p<0.05). During follow-up, there was no significant difference; MACE did not occur in any patients in the CR-GNet but occurred in controls. CONCLUSION: CR-GNet is a feasible option for the long-term management of ACS patients.

Serum Concentration of Ropivacaine After Repeated Administration to Several Parts of the Head During Awake Craniotomy: A Prospective Cohort Study.

Introduction: During awake craniotomy, effective use of local anesthetics, such as ropivacaine, is critical. Blood concentrations of ropivacaine after repeated administration over a short period during awake craniotomy have not been studied. Materials and Methods: In this prospective cohort study, we evaluated serum concentrations of ropivacaine 15 min after each administration during awake craniotomy at Nagoya University Hospital between April 5, 2018 and August 31, 2019 to determine the safe dose. A total of 30 patients scheduled to undergo elective awake craniotomy were included. Patients were injected with 0.375% ropivacaine before the awake phase at the following points: scalp block (T1), headpin area (T2), skin incision area (T3), temporal muscle (T4), and dura mater (T5). Arterial blood samples were collected 15 min after ropivacaine administration. In addition to the blood concentrations of ropivacaine, complications during the awake phase were evaluated as secondary endpoints. Results: The mean total dose of ropivacaine was 5.01 ± 0.68 mg/kg (maximum total dose: 6.30 mg/kg). The mean interval from T1 to T5 was 128.0 ± 17.7 min. The maximum serum concentration did not exceed the toxicity threshold of 4.3 µg/mL in any patient (mean serum concentration: T1, 1.23 ± 0.36 µg/mL; T5, 0.82 ± 0.26 µg/mL). No addiction symptoms were observed during awakening in any case. Conclusion: Our results show that, in cases of awake craniotomy with repeated anesthetic administration, a total dose of up to 5.0 mg/kg is safe, without addiction symptoms. Relatively large amounts of ropivacaine can be safely injected during awake craniotomy.

Successful diagnosis of humidifier lung by individual provocation test to a responsible environment, a case report.

A 52-year-old woman presented with repeating episodes of pneumonia which spontaneously resolved after hospitalization. Hypersensitivity pneumonitis was suspected, but the causative antigen was not determined whether the parakeets she kept or the humidifier she owned was causative exposure. To identify which exposure is culprit, individual provocation test to a responsible environment was sequentially conducted. First, a home-returning provocation test to the parakeet was negative. Contrarily, the humidifier provocation test to her own humidifier was positive for symptoms, radiological changes, and inflammatory responses in blood test. Finally, she was diagnosed as having humidifier lung. When several antigens are suspected to be the causative agents for hypersensitivity pneumonitis, a step-by-step provocation tests is useful.

4D Flow MR Imaging of the Left Atrium: What is Non-physiological Blood Flow in the Cardiac System?

Most cardiac diseases cause a non-physiological blood flow pattern known as turbulence around the heart and great vessels, which further worsen the disease itself. However, there is no consensus on how blood flow can be defined in disease conditions. Especially, in the left atrium, the fact that vortex flow already exists makes this debate more complicated. 3D time-resolved phase-contrast (4D flow) MRI is expected to be able to capture blood flow patterns from multiple aspects, such as blood flow velocity, stasis, and vortex quantification. Previous studies have confirmed that physiological vortex flow is predominantly induced by the higher-volume flow from the superior left pulmonary vein. In atrial fibrillation, 4D flow MRI reveals a non-physiological blood flow pattern, which information may add value to well-established clinical risk factors. Currently, the research target of LA analysis has also widened to lung surgeons, pulmonary vein stump thrombosis after left upper lobectomy. 4D flow MRI is expected to be utilized for many more variable diseases that are currently unimaginable.

Composite Clonal Analysis Reveals Transition of NSCLC Subtypes Through Accumulation of Gene Mutations: A Case Report.

We analyzed an EGFR-mutated lung cancer with a pathologic diagnosis of combined large cell neuroendocrine carcinoma with mixed adenocarcinoma subtypes. Targeted next-generation sequencing of each component suggested that mutations in RB1, TP53, and SMAD4 and apparent loss of heterozygosity of TP53 and SMAD4 accompanied the transition of different adenocarcinoma subtypes. Additional gene mutations including PTEN, MST1R, and PIK3CA were noted during transdifferentiation from acinar adenocarcinoma to large cell neuroendocrine carcinoma. Combined DNA and RNA analysis using Todai OncoPanel revealed that transdifferentiation to different pathologic subtypes occurred in a single tumor through the accumulation of gene mutations.

Factors Influencing Long-Term Blood Flow in Extracranial-to-Intracranial Bypass for Symptomatic Internal Carotid Artery Occlusive Disease: A Quantitative Study.

BACKGROUND: Maintaining the patency of extracranial-to-intracranial (EC-IC) bypass is critical for long-term stroke prevention. However, reports on the factors influencing long-term bypass patency and quantitative assessments of bypass patency are limited. OBJECTIVE: To quantitatively evaluate blood flow in EC-IC bypass using four-dimensional (4D) flow magnetic resonance imaging (MRI) and investigate factors influencing the long-term patency of EC-IC bypass. METHODS: Thirty-six adult Japanese patients who underwent EC-IC bypass for symptomatic internal carotid or middle cerebral artery occlusive disease were included. We examined the relationships between decreased superficial temporal artery (STA) blood flow volume and perioperative complications, long-term ischemic complications, patient background, and postoperative antithrombotic medications in patients for whom STA flow could be quantitatively assessed for at least 5 months using 4D flow MRI. RESULTS: The mean follow-up time was 54.7 ± 6.1 months. One patient presented with a stroke during the acute postoperative period that affected postoperative outcomes. No recurrent strokes were recorded during long-term follow-up. Two patients died of malignant disease. Seven cases of reduced flow occurred in the STA, which were correlated with single bypass (P = .0294) and nonuse of cilostazol (P = .0294). STA occlusion was observed in 1 patient during the follow-up period. Hypertension, age, smoking, dyslipidemia, and diabetes mellitus were not correlated with reduced blood flow in the STA. CONCLUSION: Double anastomoses and cilostazol resulted in long-term STA blood flow preservation. No recurrence of cerebral infarction was noted in either STA hypoperfusion or occlusion cases.

Dual-VENC 4D Flow MRI Can Detect Abnormal Blood Flow in the Left Atrium That Potentially Causes Thrombosis Formation after Left Upper Lobectomy.

PURPOSE: The purpose of the current study was to clarify the blood flow pattern in the left atrium (LA), potentially causing the formation of thrombosis after left upper lobectomy (LUL). The blood flow in the LA was evaluated and compared between LUL patients with and without thrombosis. For the evaluation, we applied highly accelerated 4D flow MRI with dual-velocity encoding (VENC) scheme, which was expected to be able to capture slow flow components in the LA accurately. METHODS: Eight volunteers and 18 patients subjected to LUL underwent dual-VENC 4D Flow MRI. Eight patients had a history of thrombosis. We measured the blood flow velocity and stasis ratio (proportion in the volume that did not exceed 10 cm/s in any cardiac phase) in the LA and left superior pulmonary vein (LSPV) stump. For visual assessment, the presence of each collision of the blood flow from pulmonary veins and vortex flow in the LA were evaluated. Each acquired value was compared between healthy participants and LUL patients, and in LUL patients with and without thrombosis. RESULTS: In LUL patients, blood flow velocity near the inflow part of the left superior pulmonary vein (Lt Upp) and mean velocity in the LA were lower, and stasis ratio in the LA was higher compared with healthy volunteers (Lt Upp 9.10 ± 3.09 vs.13.23 ± 14.19 cm/s, mean velocity in the LA 9.81 ± 2.49 vs. 11.40 ± 1.15 cm/s, and stasis ratio 25.28 ± 18.64 vs. 4.71 ± 3.03%, P = 0.008, 0.037, and < 0.001). There was no significant difference in any quantification values between LUL patients with and without thrombosis. For visual assessment, the thrombus formation was associated with no collision pattern (62.5% vs. 10%, P = 0.019) and not with vortex flow pattern (50% vs. 30%, P = 0.751). CONCLUSION: The net blood flow velocity was not associated with the thrombus formation. In contrast, a specific blood flow pattern, the absence of blood flow collision from pulmonary veins, correlates to the thrombus formation in the LA.

Utility of 4D Flow MRI in Thoracic Aortic Diseases: A Literature Review of Clinical Applications and Current Evidence.

Despite the recent technical developments, surgery on the thoracic aorta remains challenging and is associated with significant mortality and morbidity. Decisions about when and if to operate are based on a balance between surgical risk and the hazard of aortic rupture. These decisions are sometimes difficult in elective cases of thoracic aortic diseases, including aneurysms and dissections. Abnormal wall stress derived from flow alterations influences disease progression. Therefore, a better understanding of the complex hemodynamic environment inside the aortic lumen will facilitate patient-specific risk assessments of complications, which enable clinicians to provide timely prophylactic interventions. Time-resolved 3D phase-contrast (4D flow) MRI has many advantages for the in vivo assessment of flow dynamics. Recent developments in 4D flow imaging techniques has led to significant advances in our understanding of physiological flow dynamics in healthy subjects and patients with thoracic aortic diseases. In this clinically focused review of thoracic aortic diseases, we demonstrate the clinical advances acquired with 4D flow MRI from published studies. We provide a systematic overview of key evidences and considerations regarding normal thoracic aortas, thoracic aortic aneurysms, aortic dissections, and thoracic aortas with prosthetic graft replacement.