Time-resolved echo-shared parallel MRA of the lung: observer preference study of image quality in comparison with non-echo-shared sequences

Abstract

The aim of this study was to evaluate the image quality of time-resolved echo-shared parallel MRA of the lung. The pulmonary vasculature of nine patients (seven females, two males; median age: 44 years) with pulmonary disease was examined using a time-resolved MRA sequence combining echo sharing with parallel imaging (time-resolved echo-shared angiography technique, or TREAT). The sharpness of the vessel borders, conspicuousness of peripheral lung vessels, artifact level, and overall image quality of TREAT was assessed independently by four readers in a side-by-side comparison with non-echo-shared time-resolved parallel MRA data (pMRA) previously acquired in the same patients. Furthermore, the SNR of pulmonary arteries (PA) and veins (PV) achieved with both pulse sequences was compared. The mean voxel size of TREAT MRA was decreased by 24% compared with the non-echo-shared MRA. Regarding the sharpness of the vessel borders, conspicuousness of peripheral lung vessels, and overall image quality the TREAT sequence was rated superior in 75-76% of all cases. If the TREAT images were preferred over the pMRA images, the advantage was rated as major in 61-71% of all cases. The level of artifacts was not increased with the TREAT sequence. The mean interobserver agreement for all categories ranged between fair (artifact level) and good (overall image quality). The maximum SNR of TREAT did not differ from non-echo-shared parallel MRA (PA: TREAT: 273+/-45; pMRA: 280+/-71; PV: TREAT: 273+/-33; pMRA: 258+/-62). TREAT achieves a higher spatial resolution than non-echo-shared parallel MRA which is also perceived as an improved image quality.

Visualization of iliac and proximal femoral artery hemodynamics using time‐resolved 3D phase contrast MRI at 3T

“…The use of smaller targeted acquisition volumes to cover an area of interest to answer a clinical question focusing on a single arterial segment, might help to overcome limitations in spatial or temporal resolution. Further image acceleration may be achieved by the application of parallel imaging or view sharing techniques (8).…”

“…More recent developments in MRA include the application of view sharing techniques such as timeresolved imaging of contrast kinetics (TRICKS) and time-resolved echo-shared angiography technique (TREAT) (7,8) as well as image acceleration techniques such as generalized autocalibrating partially parallel acquisitions (GRAPPA) (9) or sensitivity encoding (SENSE) (10), which enable for fast CE-MRA acquisitions and time-resolved MRA (tr-CE-MRA) (7). Although CE-MRA and CTA are less invasive, both methods exclusively depict vessel morphology and geometry but do not provide information about the effect of vascular pathologies on local blood flow characteristics.…”

Detection of small pulmonary nodules in high-field MR at 3 T: evaluation of different pulse sequences using porcine lung explants

“…Its unsurpassed soft-tissue contrast for example has been used for ventilation-perfusion imaging [1][2][3][4][5][6][7][8][9]. MRI of the lung may also be used to detect and measure broadening of tumors invading the chest wall or mediastinal structures [10].…”

Functional Imaging: CT and MRI

“…(147)(148)(149) In addition to the above described imaging techniques, MRI offers the possibility to assess perfusion of the lung vascular bed by ultra-fast imaging during the injection of Gadolinium contrast. (150,151) This enables direct visualization of regional perfusion, with the possibility of some form of quantification (though this is notoriously difficult in MRI due to signal-noise properties). Several studies have now demonstrated the feasibility of this technique for assessment of normal and pathological processes.…”