BACKGROUNDTo explore the application value of MR dynamic time-resolved subtracted imaging in qualitative and quantitative assessment of blood supply by systemic artery in patients with lung cancer.

METHODSA prospective study using MR FSPGR pulse sequence dynamic scan after contrast enhancement was undertaken in fifty-one patients with lung cancer which were proved by cytology or/and histology. The time-resolved subtracted imaging were acquired using the pre- and post-enhanced images in different phases of pulmonary circulation during the first-pass period (FPP) of contrast agent. The time-signal curves of FPP at four ROI placed on pulmonary artery (PA), descending aorta (DA), mass (M) and contralateral pulmonary parenchyma (PP), and the ST (start-time) and PT (peak-time) of those four ROI were measured. The enhancement ratio of the signals of M/PP at PA/DA peak time (E MP , E MA , E PP , E PA ) were calculated.

RESULTSAccording to the time-resolved subtracted imaging during PA phase, intensity of the signal was low in 7 cases, medium in 2, but not enhanced in other 42 cases. All the 51 cancer masses were remarkably enhanced during DA phase. During FPP, the ST [(5.90±0.51)s] and PT [(12.75±0.67)s] of PP were slightly later than the ST [(4.19±0.43)s] and PT [(10.59±0.66)s] of PA, while the ST [(11.03±0.80)s] and PT [(33.62±3.06)s] of cancer masses were later than ST [(9.43±0.59)s] and PT [(19.81±4.14)s] of DA. E MA was significantly higher than E MP (91.47%±18.83% vs 15.38%±11.03%, P < 0.001), while E PP were remarkably higher than E PA (273.83%±48.60% vs 140.65%±24.40%, P < 0.001).

CONCLUSIONSMR dynamic time-resolved subtracted imaging is feasible to be a non-invasive technique in qualitative and relatively quantitative assessment of blood supply by systemic artery in patients with lung cancer.