Diffusion weighted cardiovascular magnetic resonance imaging for discriminating acute from non-acute deep venous Thrombus

Abstract

Background: The importance of discriminating acute from non-acute thrombus is highlighted. The study aims to investigate the feasibility of readout-segmented diffusion weighted (DW) cardiovascular magnetic resonance (CMR) for discrimination of acute from non-acute deep venous thrombus (DVT).

Methods: For this prospective study from December 2015 to December 2017, 85 participants (mean age = 53 years, age range = 34~74) with DVT of lower extremities underwent readout-segmented DW CMR. DVT of ≤14 days were defined as acute (n = 55) and > 14 days as non-acute (n = 30). DVT visualization on b = 0, b = 800, and apparent diffusion coefficient (ADC) images were assessed using a 4-point scale (0~3, poor~excellent). DW CMR parameters were measured using region of interest (ROI). Relative signal intensity (rSI) and ADC were compared between acute and non-acute DVT using a Mann Whitney test. Sensitivity and specificity for ADC and rSI were calculated.

Results: ADC maps had higher visualization scores than b = 0 and b = 800 images (2.7 ± 0.5, 2.5 ± 0.6, and 2.4 ± 0.6 respectively, P<0.05). The mean ADC was higher in acute DVT than non-acute DVT (0.56 ± 0.17 × 10^{- 3} vs. 0.22 ± 0.12 × 10^{- 3} mm²/s, P<0.001). Using 0.32 × 10^{- 3} mm²/s as the cutoff, sensitivity and specificity for ADC to discriminate acute from non-acute DVT were 93 and 90% respectively. Sensitivity and specificity were 73 and 60% for rSI on b = 0, and 75 and 63% for rSI on b = 800.

Conclusions: Readout segmented diffusion-weighted CMR derived ADC distinguishes acute from non-acute DVT.

Trial registration: This study is retrospectively registered.

Trial registration number: HUST-TJH-2015-146 .

Keywords: Apparent diffusion coefficient; Diffusion; MRI; Thrombus.

Fig. 1

At least two ultrasounds were needed to confirm deep venous thrombosus (DVT) age. Acute DVT: less than or equal to 14 days; non-acute DVT: > 14 days

Fig. 2

Flowchart indicating participants inclusion and exclusion. DVT age (acute/non-acute) could be determined if: 1) previous ultrasound negative, interval shorter than or equal to 14 days; or 2) previous ultrasound positive, interval > 14 days

Fig. 3

Fifty-seven years old female participant with lower extremity edema. This acute DVT was heterogeneously hypointense on SPACE (a, arrows), mixed hyper- and hypointense on T1 (b, arrow) and T2 (c, arrow) weighted images. The DVT signal on b = 0 image (d, arrow) is similar to that on T2 images. On the b = 800 image (e, arrow), the thrombus was extremely high signal. On the apparent diffusion coefficient (ADC) map (f, arrow), the thrombus was darker than background. E and F provided adequate thrombus-to-background contrast, but D did not

Fig. 4

Sixty-five years old male participant with edema and pain of calf. From left to right, the columns are an SPACE, b = 0, b = 800, and ADC map. On SPACE, this acute DVT was centrally hyperintense and peripherally hypointense. On the b = 0 and 800 images, the DVT was hyperintense. The DVT was hypointensity on ADC map. All values acquired in the regional of interest (ROI) analysis indicated acute DVT

Fig. 5

A comparison between acute and non-acute DVT. Acute thrombus (first line) and non-acute thrombus (second line) were hypointense on b = 0 (a, d), b = 800 s/mm² (b, e) image. The signal intensity was about the same for acute and non-acute thrombus, while ADC values differed greatly (c, f). Mean ADC of this acute thrombus was above the cutoff of 0.32 × 10^− 3 mm²/s, while that of non-acute thrombus was below the cutoff

Fig. 6

ADC distribution and ROC curve. Overlap of ADC could be seen between acute and non-acute DVT (a). Area under curve was 0.948 for ADC in discriminating acute from non-acute DVT (b)