Systemic Artery to Pulmonary Vein Fistula After Right Upper Lobectomy Demonstrated by 4-Dimensional Flow Magnetic Resonance Imaging

Intrapulmonary arterio-venous fistula - unusual early complication of wedge resection

We present a case of an arterio-venous fistula that developed in the early postoperative course after wedge resection of the right upper lobe. A 57-year old male treated for acute myeloid leukemia was referred from the hematology department because of a right upper lobe tumor. Wedge resection was performed. Three weeks later recurrent tumor was visualized on chest X-ray. Angio-CT diagnosed an arterio-venous fistula and the patient was scheduled for redo surgery. Completion upper lobectomy was performed and the pathological examination confirmed iatrogenic arterio-venous fistula. To our knowledge such an early complication has never been reported so far. Iatrogenic intrapulmonary arterio-venous fistulas are very rare. We present a case of such fistula that developed early after wedge resection of the right lung upper lobe tumor and presented as recurrent pulmonary mass. To the best of our knowledge this is the first description of such a case.

Four-dimensional Flow MRI: Principles and Cardiovascular Applications

In-plane phase-contrast (PC) imaging is now a routine component of MRI of regional blood flow in the heart and great vessels. In-plane PC MRI provides a volumetric, isotropic, time-resolved cine sequence that enables three-directional velocity encoding, a technique known as four-dimensional (4D) flow MRI. Recent advances in 4D flow MRI have shortened imaging times, while progress in big-data processing has improved dataset pre- and postprocessing, thereby increasing the feasibility of 4D flow MRI in clinical practice. Important technical issues include selection of the optimal velocity-encoding sensitivity before acquisition and preprocessing of the raw data for phase-offset corrections. Four-dimensional flow MRI provides unprecedented capabilities for comprehensive analysis of complex blood flow patterns using new visualization tools such as streamlines and velocity vectors. Retrospective multiplanar navigation enables flexible retrospective flow quantification through any plane across the volume with good accuracy. Current flow parameters include forward flow, reverse flow, regurgitation fraction, and peak velocity. Four-dimensional flow MRI also supplies advanced flow parameters of use for research, such as wall shear stress. The vigorous burgeoning of new applications indicates that 4D flow MRI is becoming an important imaging modality for cardiovascular disorders. This article reviews the main technical issues of 4D flow MRI and the different parameters provided by it and describes the main applications in cardiovascular diseases, including congenital heart disease, cardiac valvular disease, aortic disease, and pulmonary hypertension. Online supplemental material is available for this article. ^©RSNA, 2019 See discussion on this article by Ordovas .

Post-operative imaging of pulmonary vessels

Complications following cardiothoracic surgery are responsible for prolonged hospital stay, increase cost in patient care and increased morbidity and mortality. Vascular complications in particular are significant contributors to poor patient outcome due to either hemorrhage or thrombosis and ischemia. Evaluation of vascular complications in the postoperative patient requires a rapid and reliable imaging approach. Vascular complications after cardiothoracic surgery include pulmonary artery thrombosis, pseudoaneurysm, pulmonary vein thrombosis, vascular fistulas, stenosis and infarction. Multidetector CT (MDCT), often the imaging modality of choice, offers a one-stop-shop capability to visualize the entire cardiothoracic vasculature, airways, lung parenchyma, mediastinum and chest wall with excellent temporal and spatial resolution.