Purpose: To evaluate the feasibility of time-resolved flowsensitive MRI for the three-dimensional (3D) visualization and quantification of normal and pathological portal venous (PV) hemodynamics. Materials and Methods:Portal venous hemodynamics were evaluated in 18 healthy volunteers and 5 patients with liver cirrhosis. ECG-and adaptive respiratory navigator gated flow-sensitive 4D MRI (time-resolved 3D MRI with three-directional velocity encoding) was performed on a 3 Tesla MR system (TRIO, Siemens, Germany). Qualitative flow analysis was achieved using 3D streamlines and time-resolved particle traces originating from seven emitter planes precisely placed at anatomical landmarks in the PV system. Quantitative analysis included retrospective extraction of regional peak and mean velocities and vessel area. Results were compared with standard 2D flow-sensitive MRI and to the reference standard Doppler ultrasound.Results: Qualitative flow analysis was successfully used in the entire PV system. Venous hemodynamics in all major branches in 17 of 18 volunteers and 3 of 5 patients were reliably depicted with good interobserver agreement (kappa ¼ 0.62). Quantitative analysis revealed no significant differences and moderate agreement for peak velocities between 3D MR and 2D MRI (r ¼ 0.46) and Doppler ultrasound (US) (r ¼ 0.35) and for mean velocities between 3D and 2D MRI (r ¼ 0.41). The PV area was significantly (P < 0.01) higher in 3D and 2D MRI compared with US. Conclusion:We successfully applied 3D MR velocity mapping in the PV system, providing a detailed qualitative and quantitative analysis of normal and pathological hemodynamics.

Flow-sensitive 4D MR imaging may constitute a promising, alternative technique to Doppler US for evaluating hemodynamics in the portal venous system of patients with liver cirrhosis and may be a means of assessing pathologic changes in flow characteristics.

Purpose To evaluate influence of variation in spatio-temporal resolution and scan-rescan reproducibility on 3D visualization and quantification of arterial and portal venous (PV) liver hemodynamics at 4D flow MRI. Methods Scan-rescan reproducibility of 3D hemodynamic analysis of the liver was evaluated in 10 healthy volunteers using 4D flow MRI at 3T with three different spatio-temporal resolutions (2.4×2.0×2.4mm3, 61.2ms; 2.5×2.0×2.4mm3, 81.6ms; 2.6×2.5×2.6mm3, 80ms) and thus different total scan times. Qualitative flow analysis used 3D streamlines and time-resolved particle traces. Quantitative evaluation was based on maximum and mean velocities, flow volume and vessel lumen area in the hepatic arterial and PV systems. Results 4D flow MRI showed good inter-observer variability for assessment of arterial and PV liver hemodynamics. 3D flow visualization revealed limitations for the left intrahepatic PV branch. Lower spatio-temporal resolution resulted in underestimation of arterial velocities (mean 15%, p<0.05). For the PV system hemodynamic analyses showed significant differences in the velocities for intrahepatic portal vein vessels (p<0.05). Scan-rescan reproducibility was good except for flow volumes in the arterial system. Conclusion 4D flow MRI for assessment of liver hemodynamics can be performed with low interobserver variability and good reproducibility. Higher spatio-temporal resolution is necessary for complete assessment of the hepatic blood flow required for clinical applications.

Flow-sensitive 4D MRI is feasible for profound evaluation of arterial and portal venous hemodynamics in liver cirrhosis patients, providing additional information on the pathophysiology of the altered splanchnic system.

Venous thoracic outlet syndrome (VTOS) represents a rare disorder. Hypertrophy of the anterior scalene musculature is the cause of the compression syndrome in most cases. To our knowledge, we describe the first reported case worldwide of a venous compression syndrome caused by a congenital malformation of the 1st and 2nd ribs. Treatment by transaxillary partial rib resection was necessary and a very good postoperative result was achieved.