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Susceptibility-weighted MRI may be most effective siderotic nodule detection method

MRI performed using the susceptibility-weighted technique may detect siderotic nodules in patients with cirrhosis more effectively and result in images with better contrast and visibility than other techniques, according to recent results.

Researchers performed imaging on 46 patients with cirrhosis who had one or more siderotic nodules detected through previous screenings. All participants received CT and T1-, T2- T2*- and susceptibility-weighted MRI scans in order to determine how well susceptibility-weighted imaging (SWI) detects nodules compared with other imaging techniques. Evaluated factors included the number of nodules detected and the conspicuity of the images, which was graded on a 3-point scale, with 3 being the strongest.

The SWI and T2*-weighted techniques detected siderotic nodules in every patient in the cohort, while CT failed to detect any nodules in 75%, T1-weighted imaging in 55% and T2-weighted in 22% of participants. SWI detected a significantly higher number of nodules overall compared with T2*-weighted imaging (n=2,935 vs. n=1,696, P<.0001).

Siderotic nodules detected per patient ranged from 0 to 3.5 in CT, from 0 to 13.5 in T1-weighted images, from 0 to 80.5 in T2-weighted images, from 5 to 199 in T2*-weighted images, and from 8 to 305 in SWI. The difference in the average number of nodules detected was found to be statistically significant between SWI and every other technique (P<.0001), and no cases occurred where SWI detected fewer siderotic nodules than another technique. SWI images also provided greater lesion conspicuity than the other evaluated techniques (P<.001). The majority of SWI images (87%) were graded a 3 for conspicuity, compared with 26% of T2*-weighted images.

“ … imaging using SWI substantially improves both the conspicuity of siderotic nodules and number of detected nodules relative to other techniques, including T2*-weighted gradient-echo imaging,” the researchers wrote. “ … SWI should be a useful addition to current imaging techniques, and may prove to be the most sensitive technique for the detection and characterization of hepatic siderotic nodules in the future.”