Added value of 40 keV virtual monoenergetic images for diagnosing malignant pleural effusion on chest CT.

OBJECTIVE: This study aimed to evaluate the added value of 40 keV virtual mono-energetic images (VMIs) obtained from dual-layer detector CT (DLCT) for diagnosing malignant pleural effusion (MPE) in patients presenting with unilateral pleural effusion on chest CT. MATERIALS AND METHODS: This retrospective study included 75 patients with unilateral pleural effusion who underwent contrast-enhanced chest CT scans using DLCT. Quantitative and qualitative assessments of the visibility of pleural thickening were conducted on both conventional 120 kVp images and 40 keV VMIs. Two independent radiologists reviewed chest CT scans with or without 40 keV VMIs to detect pleural nodules or nodular thickening for the diagnosis of MPE. Diagnostic performances were compared and independent predictors of MPE were identified through multivariate logistic regression analysis using CT and clinicopathologic findings. RESULTS: Pleural thickening associated with MPE demonstrated a higher contrast-to-noise ratio value and greater visual conspicuity in 40 keV VMIs compared to benign effusions (p < 0.05). For both readers, the use of 40 keV VMIs significantly improved (p < 0.05) the diagnostic performance in terms of sensitivity and area under the curve (AUC) for diagnosing MPE through the detection of pleural nodularity. Inter-observer agreements between the two readers were substantial for both 120 kVp images alone and the combined use of 40 keV VMIs. Initial cytology results and pleural nodularity at 40 keV were identified as independent predictors of MPE. CONCLUSION: The use of 40 keV VMIs from DLCT can improve diagnostic performance of readers in detecting MPE among patients with unilateral pleural effusion.

High-Grade Surface Osteosarcoma of the Rib Mimicking a Neurogenic Tumor: Radiologic and Pathologic Findings.

Osteosarcoma commonly occurs in the intramedullary cavity of long bones such as the femur, tibia, and humerus in children and adolescents. Osteosarcoma occurring as a primary tumor in the chest wall is rare. Only a limited number of such cases have been documented in the existing literature. Herein, we present radiologic and pathologic findings of a high-grade surface osteosarcoma of the rib mimicking a neurogenic tumor in a 44-year-old woman.

Kikuchi-Fujimoto Disease in the Axilla after COVID-19 Vaccination: A Case Report.

BACKGROUND: Kikuchi-Fujimoto disease (KFD) is a rare, self-limiting inflammatory condition of unknown etiology that is characterized by fever and painful lymphadenopathy. KFD commonly involves the posterior cervical region and very rarely occurs in the axilla. CASE PRESENTATION: We report on a case of KFD that presented 3 weeks after receiving the messenger ribonucleic acid-based coronavirus disease 2019 (COVID-19) vaccine. In this case, we suspected the lesions as COVID-19 vaccination-related lymphadenopathy on the initial ultrasonographic examination. CONCLUSION: Through this case report, we highlight that KFD should be considered in the differential diagnosis of patients with axillary lymphadenopathy who have undergone COVID-19 vaccination, as unusual side effects of COVID-19 vaccination have been increasingly reported in the literature owing to the rapid development of various COVID-19 vaccines during the pandemic period. In addition, we emphasize the importance of clinical suspicion in diagnosing KFD due to the fact that axillary involvement of KFD is extremely rare.

Left Bronchial Isomerism with Right-Sided Tracheal Bronchus: A Rare Case Report.

The tracheal bronchus is a congenital bronchial branching anomaly defined as an aberrant bronchus arising in either the trachea or a main bronchus. Left bronchial isomerism is characterized by two bilobed lungs, bilateral long main bronchi, and both pulmonary arteries passing superiorly to their respective upper lobe bronchi. Left bronchial isomerism with a right-sided tracheal bronchus is a very rare combination of tracheobronchial anomalies. It has not been previously reported. We present multi-detector CT findings of a left bronchial isomerism with a right-sided tracheal bronchus of a 74 year old man.

Left-Side Contrast-Injection-Induced Pseudopathologic Vertebral Enhancement in Oncology Patients without Venous Obstruction: A Report of Two Cases.

The appearance of sclerotic bone lesions in contrast-enhanced computed tomography (CT) scans is often a significant concern for the possible presence of metastatic disease, especially in individuals with a known history of cancer. Prior research has demonstrated that in cases where patients suffer from thrombosis in major veins like the superior vena cava or the brachiocephalic vein, vertebral venous congestion can create imaging patterns on CT scans that resemble sclerotic bone metastases. However, instances of such imaging findings in patients without any form of venous obstruction are not commonly reported. In this study, we present cases of pseudopathologic vertebral enhancement observed consistently following left-side contrast injections in cancer patients devoid of venous obstruction. We aim to discuss and propose a potential mechanism for this phenomenon, drawing attention to a less commonly recognized diagnostic consideration in oncological imaging.

Airspace Enlargement with Fibrosis in a Young Heavy Smoker Mimicking Diffuse Cystic Lung Disease.

The widespread use of computed tomography (CT) has led to the increased recognition of cystic lung lesions. Multiple pulmonary cysts can be observed in heterogeneous disorders called diffuse cystic lung diseases (DCLDs), which include pulmonary Langerhans cell histiocytosis, lymphangioleiomyomatosis, lymphocytic interstitial pneumonia, and Birt-Hogg-Dubé syndrome. Recently, airspace enlargement with fibrosis (AEF) has been recognized as an entity on the spectrum of smoking-related lung diseases. We report a young male heavy smoker presenting diffuse pulmonary cysts on chest CT with suspected DCLD. However, histopathological examination of the surgical biopsy specimen revealed dilated emphysematous cysts with prominent mural fibrosis, consistent with AEF.

Application of Highly Flexible Adaptive Image Receive Coil for Lung MR Imaging Using Zero TE Sequence: Comparison with Conventional Anterior Array Coil.

(1) Background: Highly flexible adaptive image receive (AIR) coil has become available for clinical use. The present study aimed to evaluate the performance of AIR anterior array coil in lung MR imaging using a zero echo time (ZTE) sequence compared with conventional anterior array (CAA) coil. (2) Methods: Sixty-six patients who underwent lung MR imaging using both AIR coil (ZTE-AIR) and CAA coil (ZTE-CAA) were enrolled. Image quality of ZTE-AIR and ZTE-CAA was quantified by calculating blur metric value, signal-to-noise ratio (SNR), and contrast-to-noise ratio (CNR) of lung parenchyma. Image quality was qualitatively assessed by two independent radiologists. Lesion detection capabilities for lung nodules and emphysema and/or lung cysts were evaluated. Patients' comfort levels during examinations were assessed. (3) Results: SNR and CNR of lung parenchyma were higher (both p < 0.001) in ZTE-AIR than in ZTE-CAA. Image sharpness was superior in ZTE-AIR (p < 0.001). Subjective image quality assessed by two independent readers was superior (all p < 0.05) in ZTE-AIR. AIR coil was preferred by 64 of 66 patients. ZTE-AIR showed higher (all p < 0.05) sensitivity for sub-centimeter nodules than ZTE-CAA by both readers. ZTE-AIR showed higher (all p < 0.05) sensitivity and accuracy for detecting emphysema and/or cysts than ZTE-CAA by both readers. (4) Conclusions: The use of highly flexible AIR coil in ZTE lung MR imaging can improve image quality and patient comfort. Application of AIR coil in parenchymal imaging has potential for improving delineation of low-density parenchymal lesions and tiny nodules.

Bone Suppression on Chest Radiographs for Pulmonary Nodule Detection: Comparison between a Generative Adversarial Network and Dual-Energy Subtraction.

OBJECTIVE: To compare the effects of bone suppression imaging using deep learning (BSp-DL) based on a generative adversarial network (GAN) and bone subtraction imaging using a dual energy technique (BSt-DE) on radiologists' performance for pulmonary nodule detection on chest radiographs (CXRs). MATERIALS AND METHODS: A total of 111 adults, including 49 patients with 83 pulmonary nodules, who underwent both CXR using the dual energy technique and chest CT, were enrolled. Using CT as a reference, two independent radiologists evaluated CXR images for the presence or absence of pulmonary nodules in three reading sessions (standard CXR, BSt-DE CXR, and BSp-DL CXR). Person-wise and nodule-wise performances were assessed using receiver-operating characteristic (ROC) and alternative free-response ROC (AFROC) curve analyses, respectively. Subgroup analyses based on nodule size, location, and the presence of overlapping bones were performed. RESULTS: BSt-DE with an area under the AFROC curve (AUAFROC) of 0.996 and 0.976 for readers 1 and 2, respectively, and BSp-DL with AUAFROC of 0.981 and 0.958, respectively, showed better nodule-wise performance than standard CXR (AUAFROC of 0.907 and 0.808, respectively; p ≤ 0.005). In the person-wise analysis, BSp-DL with an area under the ROC curve (AUROC) of 0.984 and 0.931 for readers 1 and 2, respectively, showed better performance than standard CXR (AUROC of 0.915 and 0.798, respectively; p ≤ 0.011) and comparable performance to BSt-DE (AUROC of 0.988 and 0.974; p ≥ 0.064). BSt-DE and BSp-DL were superior to standard CXR for detecting nodules overlapping with bones (p < 0.017) or in the upper/middle lung zone (p < 0.017). BSt-DE was superior (p < 0.017) to BSp-DL in detecting peripheral and sub-centimeter nodules. CONCLUSION: BSp-DL (GAN-based bone suppression) showed comparable performance to BSt-DE and can improve radiologists' performance in detecting pulmonary nodules on CXRs. Nevertheless, for better delineation of small and peripheral nodules, further technical improvements are required.

Prediction of the possibility of laparoscopic reduction of Petersen's hernia after gastrectomy: multicenter observational cohort study.

INTRODUCTION: Petersen's hernia (PH) is a potentially fatal complication of bowel infarction that is difficult to treat by laparoscopic reduction. AIM: To define predictive computed tomography (CT) profiles to identify PH patients who would be suitable for laparoscopic reduction by a comparative analysis between patients treated by laparoscopic and open reduction. MATERIAL AND METHODS: We retrospectively collected the clinical data of patients (n = 28) who underwent PH reduction surgery after minimally invasive gastrectomy for gastric cancer in the period 2015-2018 at four training hospitals. We examined the preoperative CT scans to identify the indications for laparoscopic PH reduction. RESULTS: We compared the laparoscopic reduction group (laparoscopic group, n = 15) and the open reduction group (open group, n = 13). Patients in the laparoscopic group were younger (55.7 ±10.4) than those in the open group (69.3 ±9.1), but there were no differences in clinical or laboratory findings. We found that there were two CT profiles with significant differences between the open and laparoscopic groups: superior mesenteric vein (SMV) narrowing and small bowel dilation. We found that small bowel dilatation was an independent factor on multivariate analysis for laparoscopic PH reduction. CONCLUSIONS: We found that small bowel dilatation is the most important CT profile for identifying PH patients contraindicated for laparoscopic reduction. Despite the retrospective design of this study, these CT profiles are expected to define the scope of laparoscopic reduction in PH patients and to establish indications for the laparoscopic approach.

Diagnosis of Pulmonary Embolism in Unenhanced Dual Energy CT Using an Electron Density Image.

Dual-energy computed tomography (CT) is a promising tool, providing both anatomical information and material properties. Using spectral information such as iodine mapping and virtual monoenergetic reconstruction, dual-energy CT showed added value over pulmonary CT angiography in the diagnosis of pulmonary embolism. However, the role of non-contrast-enhanced dual energy CT in pulmonary embolism has never been reported. Here, we report a case of acute pulmonary embolism detected on an electron density image from an unenhanced dual-energy CT using a dual-layer detector system.

Transcatheter Arterial Embolization for Spontaneous Hepatic Rupture Associated with HELLP Syndrome: A Case Report.

Background: Spontaneous hepatic rupture associated with the syndrome characterized by hemolysis, elevated liver enzymes, and a low platelet count (HELLP syndrome) is a rare and life-threatening condition, and only a few cases regarding the management of this condition through transcatheter arterial embolization (TAE) have been previously reported. Case summary: Herein, we report a case involving a 35-year-old pregnant woman who presented at 28 weeks of gestation with right upper quadrant pain, hypotension, and elevated levels of liver enzymes. Transabdominal ultrasound revealed fetal death. She required an emergency cesarean section, and hepatic rupture was identified after the fetus had been delivered. Hepatic packing and TAE were performed. The postprocedural course was uneventful, and the patient was discharged 14 days after she had been admitted to our hospital. Conclusions: Spontaneous hepatic rupture associated with HELLP syndrome is a very serious condition that requires prompt and decisive management. The high maternal and fetal mortality rates associated with this condition can be reduced through early accurate diagnosis and adequate management. The findings in the reported case indicate that TAE may be an attractive alternative to surgery for the management of spontaneous hepatic rupture associated with HELLP syndrome.

Abdominal CT in patients with arms down positioning: Effect of virtual monoenergetic reconstruction on diagnostic image quality.

PURPOSE: To evaluate effect of virtual monoenergetic reconstruction on contrast-enhanced abdominal CT obtained using a dual-layer detector CT (DLCT) in patients with arms-down positioning, in comparison with conventional 120-kVp image. METHODS: A total of 162 consecutive patients who underwent abdominal CT scans using a DLCT with arms-down positioning were retrospectively enrolled. 120-kVp image and virtual monoenergetic images (VMIs) at 40-100 keV were compared for arm-induced artifact reduction capability and image quality through objective and subjective assessments. Diagnostic performance was compared between VMI with the best quality and 120-kVp image. RESULTS: VMIs at 60-100 keV showed significantly lower (p < 0.001) artifact index than 120-kVp image. Subjective severity of arm-induced streak artifacts was significantly (p < 0.001) lower in VMIs at 70-100 keV than in 120-kVp image. CNRs measured in artifact and reference areas were superior (p < 0.05) in 40-70 keV to those in 120 kVp. Overall image quality was superior (p < 0.05) in 60-90 keV to 120 kVp. 70-keV VMI was chosen as the best image by two independent readers. In ROC analysis of lesion detection in the liver, spleen, and kidneys, the AUC was significantly higher for 70-keV VMI (reader 1, 0.962; p = 0.011; reader 2, 0.981; p = 0.012) than that for 120-kVp image (reader 1, 0.891; reader 2, 0.922). CONCLUSION: The70-keV VMI from DLCT could improve abdominal CT images by reducing streak artifacts and increasing image contrast in patients who could not elevated their arms. The 70-keV VMI showed better diagnostic performance than the conventional 120 kVp image.

Aberrant Left Subclavian Artery-Esophageal Fistula in a Patient with a Prolonged Use of Nasogastric Tube: A Case Report and Literature Review.

Arterial-esophageal fistula is a rare but potentially fatal complication. Right aortic arch with aberrant left subclavian artery is a rare congenital vascular anomaly that can cause esophageal compression, particularly when the proximal portion of the aberrant subclavian artery forms a Kommerell's diverticulum. Prolonged use of a nasogastric tube can cause pressure necrosis of the esophagus. We report a patient with massive gastrointestinal bleeding secondary to aberrant left subclavian artery-esophageal fistula after a prolonged use of nasogastric tube. A high index of suspicion is essential for better prognosis when a patient with congenital aortic arch anomaly shows upper gastrointestinal hemorrhage.

Diagnosis of multiple pulmonary cavernous hemangiomas via dual-layer spectral CT: A case report.

RATIONALE: Cavernous hemangioma is a benign vascular tumor, which very rarely occurs in the lung. When appearing as multiple nodules on chest CT, this tumor can be misdiagnosed as metastatic malignancy. PATIENT CONCERNS: A 72-year-old woman presented with incidentally found multiple lung nodules on chest radiograph. DIAGNOSES: Based on information derived from dual-layer spectral CT images, the possibility of slow flow vascular tumor such as cavernous hemangioma was suggested. A pathologic diagnosis of pulmonary cavernous hemangioma was made via video-assisted thoracoscopic biopsy. INTERVENTIONS: After tissue confirmation, the patient was discharged without further intervention. OUTCOMES: The patient recovered without any event. Follow-up chest CT performed 6 months later showed no significant interval change in nodule size and distribution. LESSONS: Material decomposition images obtained from dual energy CT can help physicians understand the character of tumor vascularity for an accurate diagnosis of pulmonary cavernous hemangioma.

Pneumothorax after CT-guided transthoracic lung biopsy: A comparison between immediate and delayed occurrence.

BACKGROUND: In CT-guided transthoracic lung biopsy (CTLB), pneumothorax can occur as a late complication (delayed pneumothorax). The incidence, risk factors, and clinical significance of delayed pneumothorax are not well known. OBJECTIVES: To compare the risk factors for immediate and delayed pneumothorax after CTLB and to know their clinical significance. METHODS: Images and medical records of 536 consecutive patients who underwent CTLB were reviewed. All biopsies were performed as inpatient procedures. Follow-up chest radiographs were obtained at least twice at 4 h after procedure and before discharge. Risk factors for immediate and delayed pneumothorax were assessed based on patient-, lesion-, and procedure-related variables. Rates of chest tube insertion were also compared. RESULTS: Pneumothorax developed in 161 patients (30.0%) including 135 (25.2%) immediate and 26 (4.9%) delayed cases. Lesion size was an independent risk factor for both immediate and delayed pneumothorax (OR = 0.813; CI = 0.717-0.922 and OR = 0.610; CI = 0.441-0.844, respectively). While emphysema, lower lobe location, and long intrapulmonary biopsy track were risk factors (OR = 1.981; CI = 1.172-3.344, OR = 3.505; CI = 2.718-5.650, and OR = 1.330; CI = 1.132-1.563, respectively) for immediate pneumothorax, upper lobe location and increased number of pleural punctures were independent risk factors (OR = 5.756; CI = 1.634-20.274 and OR = 3.738; CI = 1.860-7.511, respectively) for delayed pneumothorax. The rate of chest tube insertion was significantly (p < 0.001) higher in delayed pneumothorax. CONCLUSION: Pneumothorax tends to occur immediately after CTLB in patients with emphysema, lower lobe lesion, and long intrapulmonary biopsy track. Further attention and warnings are needed for those with multiple punctures of small lesions involving upper lobes due to the possibility of delayed development of pneumothorax and higher requirement for chest tube drainage.

Feasibility Study of Synthetic Diffusion-Weighted MRI in Patients with Breast Cancer in Comparison with Conventional Diffusion-Weighted MRI.

OBJECTIVE: To investigate the clinical feasibility of synthetic diffusion-weighted imaging (sDWI) at different b-values in patients with breast cancer by assessing the diagnostic image quality and the quantitative measurements compared with conventional diffusion-weighted imaging (cDWI). MATERIALS AND METHODS: Fifty patients with breast cancer were assessed using cDWI at b-values of 800 and 1500 s/mm² (cDWI800 and cDWI1500) and sDWI at b-values of 1000 and 1500 s/mm² (sDWI1000 and sDWI1500). Qualitative analysis (normal glandular tissue suppression, overall image quality, and lesion conspicuity) was performed using a 4-point Likert-scale for all DWI sets and the cancer detection rate (CDR) was calculated. We also evaluated cancer-to-parenchyma contrast ratios for each DWI set in 45 patients with the lesion identified on any of the DWI sets. Statistical comparisons were performed using Friedman test, one-way analysis of variance, and Cochran's Q test. RESULTS: All parameters of qualitative analysis, cancer-to-parenchyma contrast ratios, and CDR increased with increasing b-values, regardless of the type of imaging (synthetic or conventional) (p < 0.001). Additionally, sDWI1500 provided better lesion conspicuity than cDWI1500 (3.52 ± 0.92 vs. 3.39 ± 0.90, p < 0.05). Although cDWI1500 showed better normal glandular tissue suppression and overall image quality than sDWI1500 (3.66 ± 0.78 and 3.73 ± 0.62 vs. 3.32 ± 0.90 and 3.35 ± 0.81, respectively; p < 0.05), there was no significant difference in their CDR (90.0%). Cancer-to-parenchyma contrast ratios were greater in sDWI1500 than in cDWI1500 (0.63 ± 0.17 vs. 0.55 ± 0.18, p < 0.001). CONCLUSION: sDWI1500 can be feasible for evaluating breast cancers in clinical practice. It provides higher tumor conspicuity, better cancer-to-parenchyma contrast ratio, and comparable CDR when compared with cDWI1500.

Meandering pulmonary veins: Two case reports.

RATIONALE: Meandering pulmonary vein is a rare congenital pulmonary vascular anomaly. It presents unilateral single pulmonary vein that takes a circuitous route in the lung and drains normally into the left atrium. Most cases of meandering pulmonary vein have been reported to be right-sided. A few of them coincided with features of scimitar syndrome. PATIENT CONCERNS: A 71-year-old woman and a 20-year-old man presented with incidentally found abnormal findings on chest radiographs. DIAGNOSIS: Through multi-detector chest computed tomography, the 71-year-old woman was diagnosed as left-sided meandering pulmonary vein without any other anomalies while the 20-year-old man was diagnosed as having right-sided meandering pulmonary vein with features of scimitar syndrome. INTERVENTIONS: Specific intervention was not performed for either patient. OUTCOMES: These patients were reassured and discharged. They are doing well without any respiratory symptoms. LESSONS: Meandering pulmonary veins can occur on the left side and coincide with features of scimitar syndrome. Multi-detector computed tomography with 3D reconstruction allows clear depiction of vascular connections and associated anomalies, obviating the need for invasive procedures.

Quantification of liver extracellular volume using dual-energy CT: utility for prediction of liver-related events in cirrhosis.

OBJECTIVES: To determine whether quantification of liver extracellular volume fraction (fECV) using dual-energy CT (DECT) allows prediction of liver-related events (LREs) in cirrhotic patients. METHODS: This retrospective study included 305 cirrhotic patients who underwent dual-source DECT imaging and had serum markers analyzed within 2 weeks of initial CT imaging. The fECV score was measured using an iodine map of equilibrium-phase images obtained 3 min after contrast injection at 100/140 Sn kVp. The association of the fECV score and serum markers with LREs was investigated. A risk model combining the fECV score (< 27 versus ≥ 27%) and serum albumin level (< 4 versus ≥ 4 g/dL) was constructed for LRE prediction. RESULTS: An increased fECV score (odds ratio, 1.27; 95% confidence interval (CI), 1.15, 1.40) was independently associated with decompensated cirrhosis at baseline (n = 85) along with the Model for End-Stage Liver Disease score (odds ratio, 1.32; 95% CI, 1.07, 1.63). Among patients with compensated cirrhosis, 10.5% (23 of 220) experienced LREs during the median follow-up period of 2.0 years (decompensation, n = 14; hepatocellular carcinoma, n = 9). The fECV score (hazard ratio, 1.40; 95% CI, 1.22, 1.62) and serum albumin level (hazard ratio, 0.26; 95% CI, 0.09, 0.73) were independent predictors of LRE. The mean times to LRE among the high (16.5 months, n = 18)-, intermediate (25.6 months, n = 44)-, and low (30.5 months, n = 158)-risk groups were significantly different (p < 0.001). CONCLUSIONS: The fECV score derived from DECT allows prediction of LREs in cirrhotic patients. KEY POINTS: • The extracellular volume fraction (fECV) score derived from the iodine map of dual-energy CT (DECT) was independently associated with the presence of hepatic decompensation. • The fECV score derived from the iodine map of DECT can predict liver-related events (LREs) in patients with cirrhosis. • Equilibrium-phase scanning in dual-energy mode is recommended as part of liver CT in cirrhotic patients because it can provide a prognostic indicator for LRE development.

Respiratory motion-resolved four-dimensional zero echo time (4D ZTE) lung MRI using retrospective soft gating: feasibility and image quality compared with 3D ZTE.

OBJECTIVES: To evaluate the feasibility and image quality of respiratory motion-resolved 4D zero echo time (ZTE) lung MRI compared with that of 3D ZTE. METHODS: Our institutional review board approved this study. Twenty-one patients underwent lung scans using 3D ZTE and 4D ZTE sequences via prospective and retrospective soft gating techniques, respectively. Image qualities of 3D ZTE and 4D ZTE at end-expiration were compared through objective and subjective assessments. The quality of end-expiratory images of 3D ZTE and 4D ZTE of the two groups with different lung functions was also compared. RESULTS: Images were successfully acquired in all patients without any adverse events. Signal-to-noise ratios (SNRs) of lung parenchyma and thoracic structures were significantly (all p < 0.001) higher in 4D ZTE. Contrast-to-noise ratios (CNRs) of peripheral bronchi, peripheral pulmonary vessels, and nodules or masses were significantly (all p < 0.001) higher in 4D ZTE. The subjective image quality assessed by two independent radiologists showed that intrapulmonary structures, noise and artifacts, and overall acceptability were superior in 4D ZTE (all p < 0.001). Image qualities of groups with normal and low lung functions differed significantly (all p < 0.05) in 3D ZTE, but not in 4D ZTE. The mean acquisition time was 136 s (127-143 s) in 3D ZTE and 325 s (308-352 s) in 4D ZTE. CONCLUSIONS: Respiratory motion-resolved 4D ZTE lung imaging was feasible as part of routine chest MRI. The 4D ZTE provides motion-robust lung parenchymal images with better SNR and CNR than the 3D ZTE, regardless of patients' lung function. KEY POINTS: • ZTE MRI captures rapidly decaying transverse magnetization in the lung parenchyma. • 4D ZTE provides motion-robust lung parenchymal images with better SNR and CNR compared with 3D ZTE. • Compared with 3D ZTE, the image quality of 4D ZTE lung MRI was affected less by patients' lung function and respiratory performance.

Correction to: T1 mapping for liver function evaluation in gadoxetic acid-enhanced MR imaging: comparison of look-locker inversion recovery and B1 inhomogeneity-corrected variable flip angle method.

The original version of this article, published on 22 March 2019, unfortunately contained a mistake. The following correction has therefore been made in the original: Affiliations 1 and 2 were presented incorrectly.