Protein interaction networks characterizing the A549 cells Klotho transfected are associated with activated pro-apoptotic Bim and suppressed Wnt/ß-catenin signaling pathway.

Invasive assays and lung tumor-bearing mice models using a human lung adenocarcinoma cell line A549 cells transfected with the Klotho (KL) gene, A549/KL cells, have confirmed that KL suppresses invasive/metastatic potential. This study aimed to identify the co-expression protein networks and proteomic profiles associated with A549/KL cells to understand how Klotho protein expression affects molecular networks associated with lung carcinoma malignancy. A two-step application of a weighted network correlation analysis to the cells' quantitative proteome datasets of a total of 6,994 proteins, identified by mass spectrometry-based proteomic analysis with data-independent acquisition (DIA), identified one network module as most significantly associated with the A549/KL trait. Upstream analyses, confirmed by western blot, implicated the pro-apoptotic Bim (Bcl-2-like protein 11) as a master regulator of molecular networks affected by Klotho. GeneMANIA interaction networks and quantitative proteome data implicated that Klotho interacts with two signaling axes: negatively with the Wnt/ß-catenin axis, and positively by activating Bim. Our findings might contribute to the development of future therapeutic strategies.

[Perioperative Rehabolotation Usefulness in Preventing Complications].

The number of elderly patients in thoracic surgery is increasing. The percentage of patients over the age of 80 in surgical cases of malignant diseases such as lung cancer and mediastinal tumors is increasing every year. It is also true that the indications for surgery have been expanding as surgery itself has become less invasive, such as thoracoscopic and robotic surgery. However, it is not uncommon for patients over 80 years of age to have some organ dysfunction and many comorbidities. Therefore, when performing surgery for lung cancer and other diseases, it is important to assess the patient's ability to tolerate surgery, including respiratory and cardiac functions, and to perform risk management. To prevent postoperative complications and improve the accuracy of perioperative management, respiratory rehabilitation should be conducted before and after surgery, and not only smoking cessation instruction but also inhalation training using incentive spirometry( IS), breathing exercises, and the use of inhalers such as long-acting ß2 agonist (LABA)/long-acting muscaring antagonist (LAMA) for patients with chronic obstructive pulmonary disease( COPD) are useful.

Prognostic role of preoperative fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography with an image-based harmonization technique: A multicenter retrospective study.

Objectives: Despite the prognostic impacts of preoperative fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography examination, fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography-based prognosis prediction has not been used clinically because of the disparity in data between institutions. By applying an image-based harmonized approach, we evaluated the prognostic roles of fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters in clinical stage I non-small cell lung cancer. Methods: We retrospectively examined 495 patients with clinical stage I non-small cell lung cancer who underwent fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography examinations before pulmonary resection between 2013 and 2014 at 4 institutions. Three different harmonization techniques were applied, and an image-based harmonization, which showed the best-fit results, was used in the further analyses to evaluate the prognostic roles of fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters. Results: Cutoff values of image-based harmonized fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters, maximum standardized uptake, metabolic tumor volume, and total lesion glycolysis were determined using receiver operating characteristic curves that distinguish pathologic high invasiveness of tumors. Among these parameters, only the maximum standardized uptake was an independent prognostic factor in recurrence-free and overall survivals in univariate and multivariate analyses. High image-based maximum standardized uptake value was associated with squamous histology or lung adenocarcinomas with higher pathologic grades. In subgroup analyses defined by ground-glass opacity status and histology or by clinical stages, the prognostic impact of image-based maximum standardized uptake value was always the highest compared with other fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography parameters. Conclusions: The image-based fluorine-18 fluorodeoxyglucose-positron emission tomography/computed tomography harmonization was the best fit, and the image-based maximum standardized uptake was the most important prognostic marker in all patients and in subgroups defined by ground-glass opacity status and histology in surgically resected clinical stage I non-small cell lung cancers.

Development of a new minimally invasive phototherapy for lung cancer using antibody-toxin conjugate.

BACKGROUND: Photodynamic therapy (PDT) is a cancer-targeted treatment that uses a photosensitizer (PS) and laser irradiation. The effectiveness of current PDT using red light for advanced cancers is limited, because red light can only reach depths within a few millimeters. To enhance the antitumor effect for lung cancers, we developed a new phototherapy, intelligent targeted antibody phototherapy (iTAP). This treatment uses a combination of immunotoxin and a PS, mono-L-aspartyl chlorin e6 (NPe6). METHODS: We examined whether cetuximab encapsulated in endosomes was released into the cytosol by PS in PDT under light irradiation. A431 cells were treated with fluorescein isothiocyanate-labeled cetuximab, NPe6, and light irradiation and were observed with fluorescence microscopy. We analyzed the cytotoxicity of saporin-conjugated cetuximab (IT-cetuximab) in A431, A549, and MCF7 cells and the antitumor effect in model A549-bearing mice in vivo using the iTAP method. RESULTS: Fluorescent microscopy analysis showed that the photodynamic effect of NPe6 (20 µM) and light irradiation (37.6 J/cm2 ) caused the release of cetuximab from the endosome into the cytosol. In vitro analysis demonstrated that the iTAP method enhanced the cytotoxicity of IT-cetuximab by the photodynamic effect. In in vivo experiments, compared with IT-cetuximab alone or PDT alone, the iTAP method using a low dose of IT-cetuximab showed the greatest enhancement of the antitumor effect. CONCLUSIONS: Our study is the first report of the iTAP method using NPe6 for lung cancer cells. The iTAP method may become a new, minimally invasive treatment superior to current PDT methods.

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.

Alpha-actinin-4 (ACTN4) gene amplification is a predictive biomarker for adjuvant chemotherapy with tegafur/uracil in stage I lung adenocarcinomas.

Although adjuvant tegafur/uracil (UFT) is recommended for patients with completely resected stage I non-small-cell lung cancer (NSCLC) in Japan, only one-third of cases has received adjuvant chemotherapy (ADJ) according to real-world data. Therefore, robust predictive biomarkers for selecting ADJ or observation (OBS) without ADJ are needed. Patients who underwent complete resection of stage I lung adenocarcinoma with or without adjuvant UFT were enrolled. The status of ACTN4 gene amplification was analyzed by FISH. Statistical analyses to determine whether the status of ACTN4 gene amplification affected recurrence-free survival (RFS) were carried out. Formalin-fixed, paraffin-embedded samples from 1136 lung adenocarcinomas were submitted for analysis of ACTN4 gene amplification. Ninety-nine (8.9%) of 1114 cases were positive for ACTN4 gene amplification. In the subgroup analysis of patients aged 65 years or older, the ADJ group had better RFS than the OBS group in the ACTN4-positive cohort (hazard ratio [HR], 0.084, 95% confidence interval [CI], 0.009-0.806; P = .032). The difference in RFS between the ADJ group and the OBS group was not significant in ACTN4-negative cases (all ages: HR, 1.214; 95% CI, 0.848-1.738; P = .289). Analyses of ACTN4 gene amplification contributed to the decision regarding postoperative ADJ for stage I lung adenocarcinomas, preventing recurrence, improving the quality of medical care, preventing the unnecessary side-effects of ADJ, and saving medical costs.

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.

New Technique for Introducing a Surgical Stapler during Robot-Assisted Lobectomy for Lung Cancer.

BACKGROUND: The da Vinci Si version robot lacks a vascular stapler that can be controlled by the operating surgeon at the surgical console when dividing pulmonary vessels. Therefore, to initiate and safely perform robotic anatomical lobectomy for lung cancer, it is important to develop a safe method for introducing a surgical stapler. METHODS: We performed a retrospective study of the first 42 consecutive patients who underwent robotic lobectomy for lung cancer at Nippon Medical School Hospital between January 2019 and December 2020. RESULTS: Up to case 18, we performed robot-assisted thoracoscopic surgery (RATS) lobectomy by using a four-arm approach with two assistant ports. For dividing pulmonary vessels, the surgical stapler was introduced through the assist ports. However, since this is not the port position usually used in video-assisted thoracoscopic surgery (VATS), there were many difficult situations. For RATS lobectomy case 19 and all subsequent cases, we utilized a total port approach that uses three robotic arms and two assistant ports. To resect the pulmonary vessels or bronchi with endoscopic staplers, the port for the robotic arm was removed and the endoscopic staplers were placed through a 12-mm Xcel bladeless port. This change reduced operation time, blood loss, and robotic arm interference. No patient developed intraoperative complications during RATS lobectomy. CONCLUSION: The present total port approach, with three robotic arms, appears to be feasible for introducing surgical staplers during RATS with the da Vinci Si robotic system.

CADM1 and SPC25 Gene Mutations in Lung Cancer Patients With Idiopathic Pulmonary Fibrosis.

INTRODUCTION: To investigate the genomic profiles of patients with lung cancer with idiopathic pulmonary fibrosis (IPF-LC), mechanism of carcinogenesis, and potential therapeutic targets. METHODS: We analyzed 29 matched, surgically resected, cancerous and noncancerous lung tissues (19 IPF-LC and 10 non-IPF-LC) by whole-exome sequencing and bioinformatics analysis and established a medical-engineering collaboration with the Department of Engineering of the Tokyo University of Science. RESULTS: In IPF-LC, CADM1 and SPC25 were mutated at a frequency of 47% (9 of 19) and 53% (10 of 19), respectively. Approximately one-third of the IPF-LC cases (7 of 19; 36%) had both mutations. Pathway analysis revealed that these two genes are involved in transforming growth factor-ß1 signaling. CADM1 and SPC25 gene mutations decreased the expression of CADM1 and increased that of SPC25 revealing transforming growth factor-ß1-induced epithelial-to-mesenchymal transition and cell proliferation in lung cancer cells. Furthermore, treatment with paclitaxel and DNMT1 inhibitor suppressed SPC25 expression. CONCLUSIONS: CADM1 and SPC25 gene mutations may be novel diagnostic markers and therapeutic targets for IPF-LC.

Usefulness of simultaneous type image-enhanced endoscope system in photodynamic therapy for centrally located lung cancer.

BACKGROUND: Photodynamic therapy (PDT) is established as one of the standard treatment options for centrally located early lung cancer. In order to improve the effectiveness of PDT, it is very important to accurately diagnose the extent of the tumor and focus the laser irradiation accurately. With the use of the conventional video-endoscope system, which adopts the frame-sequential (RGB-based) display method, mainly used in Japan, for PDT laser irradiation, the system only recognizes the strong white light, and color information is lost. Therefore, it is difficult to irradiate the lesion while simultaneously observing the lesion. In this study, we investigated the usefulness of a new type of video-endoscope system during PDT. METHODS: We used ELUXEO 7000® (FUJIFILM, Japan), which is a simultaneous-type video-endoscope system that has been in use at Nippon Medical School Hospital since October 2018. We analyzed the clinical usefulness of the ELUXEO® system for PDT as compared to other endoscope systems, such as EVIS LUCERA ELITE® (Olympus, Japan), an autofluorescence imaging (AFI) system. RESULTS: After the administration of talaporfin sodium for PDT, the tumor lesion was not visualized in magenta color with AFI, yielding false-negative results. On the other hand, no false-negative results after the administration of talaporfin sodium were obtained with the use of ELUXEO®. Using the ELUXEO® system in the blue light imaging (BLI) mode, we were able to deliver a red laser light while observing the extent of the tumor. Missed laser exposure was avoided and the accuracy of PDT was improved with the use of this system. CONCLUSIONS: ELUXEO® is useful for accurate evaluation of the extent of centrally located lung cancer and therefore, for accurate laser irradiation of the tumor lesion.

Antiaging gene Klotho regulates epithelial-mesenchymal transition and increases sensitivity to pemetrexed by inducing lipocalin-2 expression.

Epithelial-mesenchymal transition (EMT) is considered to serve an important role in the metastatic/invasive ability of cancer cells, in the acquisition of drug resistance, and in metabolic reprogramming. In the present study, it was hypothesized that the Klotho gene is involved in the metastatic/invasive ability of lung cancer. We previously reported an association between Klotho expression and overall survival in patients with small cell lung cancer and large cell neuroendocrine cancer. We also found that Klotho expression was associated with EMT-related molecules in lung squamous cell carcinoma. The present study aimed to analyze the function of the Klotho gene and to elucidate its relevance to the regulation of the EMT. For this purpose, GFP-Klotho plasmids were transfected into lung adenocarcinoma cells (A549) and cell lines with stable expression (A549/KL-1 and A549/KL-2) were established. A549/KL-1 cells expressed higher levels of Klotho protein by western blot analysis compared with A549/KL-2 cells. In western blotting of A549 and A549/KL-1 cells, the expression of the mesenchymal marker N-cadherin was found to be completely inhibited in A549/KL-1 cells suggesting that Klotho expression may regulate the EMT in cancer cells via the inhibition of N-cadherin. The results of the sensitivity tests demonstrated that A549/KL-1 cells were significantly more sensitive to pemetrexed compared with A549 cells (IC50 A549/KL-1 vs. A549 cells, 0.1 µM vs. 0.7 µM). The results of the microarray analysis demonstrated that a very high level of lipocalin-2 (LCN2) expression was induced in the A549/KL-1 cells. Klotho overexpression completely suppressed the expression of mesenchymal markers, such as N-cadherin and Snail1 (Snail). The results of the present study suggested that there may be a new mechanism of action for the antitumor effects of pemetrexed, namely, LCN2-mediated modulation of N-cadherin expression. Klotho expression during cancer treatment has great potential as a predictor for efficacy of pemetrexed and as a factor in the selection of personalized medicine for postoperative adjuvant chemotherapy.

[Therapeutic Strategies for Metachronous Multiple Primary Lung Cancer].

BACKGROUNDS: It is not uncommon to encounter metachronous primary lung cancer after surgical treatment along with the increase in the elderly patients. In consideration of increasing number of such patients, it is necessary to take various treatment strategies. METHODS: In order to establish a treatment strategy for multiple lung cancer, we retrospectively examined multiple lung cancer cases operated for primary lung cancer in our department from January 2013 to December 2019, and the future treatment strategy was examined. RESULTS: Of 821 patients who underwent surgery for primary lung cancer, 61 were multiple lung cancers, 31 were synchronous multiple lung cancers, and 30 were metachronous multiple lung cancers. Among the cases of metachronous multiple lung cancer, 28 cases had undergone lobectomy or more in the first operation, 1 case of segmental resection, and 1 case of partial resection. As for the treatment of secondary lung cancer lesions, 21 lesions were performed surgery( lobectomy;2, segmental resection;2, partial resection;17), 6 lesions of photodynamic therapy (PDT), and 3 lesions of stereotactic body radiation therapy (SBRT). Among the surgical cases, there were three cases on the same side as the first cancer and 18 cases on the opposite side. The three cases underwent partial resection. Among 21 patients, postoperative home oxygen therapy was introduced in 2 patients. Regarding the prognosis, three patients who had surgical resection, died of recurrence of the first lesion. One of the six PDT patients died of recurrence of the first lung cancer and another died of other disease. All three patients who underwent SBRT are alive without recurrence. CONCLUSIONS: If early detection and early diagnosis are made as a treatment strategy for metachronous multiple lung cancer, it may be possible to preserve lung function by reducing surgery or SBRT, PDT, and to cure without damaging the quality of life.

A Case of Pulmonary Adenofibroma Treated by Thoracoscopic Resection.

Pulmonary adenofibroma is a rare biphasic tumor that contains epithelial and stromal components. We report a case of pulmonary adenofibroma in which the tumor was resected by thoracoscopic surgery and the diagnosis was established by histopathology. A 59-year-old woman with a past medical history of pyelonephritis visited our hospital for evaluation of an abnormal opacity on a plain chest x-ray during a comprehensive medical examination. A follow-up chest x-ray showed enlargement of the lesion, and the patient was referred to our department for further management. Chest computed tomography revealed a well-circumscribed nodule measuring 1.4 cm in diameter in the upper lobe of the left lung. The chest imaging findings suggested a benign tumor, but because of evidence of lesion enlargement and elevated serum carcinoembryonic antigen levels, we performed wide wedge resection of the left upper lobe by video-assisted thoracoscopic surgery, for diagnosis and treatment. The resected specimen was submitted for rapid pathological diagnosis during the operation, and a benign tumor, possibly sclerosing pneumocytoma, was suspected. Therefore, we completed the operation with wide wedge resection. The final histopathological diagnosis was pulmonary adenofibroma. The patient had an uneventful postoperative course, and at this writing, 6 months postoperatively, there has been no evidence of tumor recurrence. We have reported this case of pulmonary adenofibroma because the tumor is rare, has not yet been well-characterized, and has an unclear prognosis. Collection of data from a larger number of patients is necessary.

Correction to: Left upper lobectomy is a risk factor for cerebral infarction after pulmonary resection: a multicentre, retrospective, case-control study in Japan.

The original article can be found online.

Left upper lobectomy is a risk factor for cerebral infarction after pulmonary resection: a multicentre, retrospective, case-control study in Japan.

PURPOSE: The anatomical site of resected lobes may influence postoperative cerebral infarction. The objective of the current study was to determine if left upper pulmonary lobectomy is a risk factor for postoperative cerebral infarction. METHODS: This was a retrospective case-control study in patients undergoing pulmonary lobectomy from 2004 to 2013 in Japan. We retrospectively identified 610 patients from 153 institutions who had developed postoperative cerebral infarction following pulmonary lobectomy. The control group consisted of 773 patients who underwent lobectomy without cerebral infarction during a randomly selected single month in 2009 at the same institutions. RESULTS: Factors associated with cerebral infarction were age [10-year intervals, odds ratio (OR): 1.46; 95% confidence interval (CI): 1.23-1.73; p < 0.001], male sex (OR 1.92; 95% CI 1.29-2.86; p = 0.001), presence of comorbidities (OR 1.82; 95% CI 1.35-2.44; p < 0.001), perioperative anti-platelet or anti-coagulant drug use (OR 1.71; 95% CI 1.20-2.45; p = 0.003), and lobectomy. Subgroup analyses revealed that cerebral infarction was strongly associated with left upper lobectomy. CONCLUSIONS: Our findings suggest that left upper lobectomy is associated with a higher risk of cerebral infarction than other types of lobectomy, particularly in the early postoperative period.

[Perspective of Uniportal Video-assisted Thoracic Surgery for Early Lung Cancer in Japan].

Uniportal video-assisted thoracic surgery (U-VATS) has become prevalent among thoracic surgeon in a part of countries including Japan. U-VATS and robotic-assisted thoracoscopic surgery( RATS) are 2 types of minimally invasive surgical techniques. Uniportal procedures are feasible although they can be technically challenging. RATS is superior to U-VATS in terms of the ability to perform procedures that require fine motor skills and to maintain wide visual fields during the procedure;however, it is not as feasible and more costly compared with U-VATS. U-VATS is also considered safer as it is easier than RATS to be converted to thoracotomy when needed. Thus, suitable procedures should be selected to meet the needs of specific cases. In the present study, we review the treatment outcomes of U-VATS for anatomical lung resection that were performed at our institution for patients with early-stage lung cancer.

Partial lung resection by uniportal video-assisted thoracoscopic surgery: technique and pitfalls.

The use of uniportal video-assisted thoracoscopic surgery (VATS) has increased worldwide. The number of facilities introducing this simple and cost-effective surgical procedure in Japan has also increased. Partial lung resection is performed to diagnose or treat various cases and surgeons are required to flexibly deal with it. This report describes the technique and pitfalls of partial lung resection by uniportal VATS.

Clinical trial of photodynamic therapy for peripheral-type lung cancers using a new laser device in a pilot study.

INTRODUCTION/AIM: Photodynamic therapy (PDT) involves the use of a tumor-specific photosensitizer and laser irradiation, and is one of the treatment options recommended for early centrally located lung cancers, but not yet for peripheral-type lung cancers. We developed a new laser probe, the composite-type optical fiberscope (COF), which allows accurate laser irradiation of a cancer lesion with simultaneous visualization of the lesion. In this study, we attempted a new endobronchial PDT technique using the new laser probe, and evaluated the effectiveness and feasibility of this novel PDT technique for peripheral lung cancers. METHODS: This phase I study was conducted in 7 patients with peripheral lung cancers (primary tumor ≤20 mm in diameter). We performed endobronchial PDT for these patients using the new laser probe and talaporfin sodium as the photosensitizer. RESULTS: We performed PDT for 3 patients with peripheral lung cancer using a laser dose of 50 J/cm2 at 120 mW, and confirmed the feasibility of using this dose. Then, we escalated the laser dose to 100 J/cm2 in 4 additional patients. A total of 7 patients met our inclusion criteria. Evaluation at 2 weeks and 3 months after the PDT revealed no complication such as pneumonia or pneumothorax. At the evaluation conducted 6 months later, we found CR in 3 cases and SD in the remaining 4 cases. CONCLUSION: PDT was found to be a feasible and non-invasive treatment modality for early peripheral-type lung cancer. In the future, PDT could become a standard treatment option for peripheral-type lung cancer.

4D Flow MR Imaging Reveals a Decrease of Left Atrial Blood Flow in a Patient with Cardioembolic Cerebral Infarction after Pulmonary Left Upper Lobectomy.

We present the case of a 76-year-old woman who underwent left upper lobectomy for lung adenocarcinoma. Three days after the surgery, a thrombus was observed in the pulmonary vein (PV) stump. Four months after the surgery, we performed 4D flow MRI, which revealed decreased blood flow, not only in the left superior PV stump, but also over a widespread region around the left atrium-left superior PV junction. 4D flow MRI can clarify the altered hemodynamics underlying thrombus formation.