Comparative study of diffusion weighted imaging and dynamic contrast enhanced MRI for the detection of small breast cancers

Abstract

Objecfive To compare the sensitivity of diffusion weighted imaging(DWI)with dynamic contrast enhanced(DeE)MRI for the detection of small breast caJlcers and to evaluate the clinical value of DWI.Methods Forty-eight patients with benign(n=25)and malignant(n=45)small breast lesions(≤2 cm)proved by pathology underwent DWI and DCE MRI.The DCE MRI was performed using FLASH sequence and the time-signal intensity chive was drawn.The DWl was performed using GRAPPAEPI sequence with different b values(800,1000 s/mm2) and the ADC values of lesions were measured.The sensitivity and specificity of DWI for the detection of small breast cancers were compared with DCE MRI. Results Forty of 45 small breast cancers and 19 of 25 small benign breast lesions were corrlectly diagnosed using DCE MRI.The sensitivity and positive predictive value of TIC were 88.9%(40/45)and 87.0%(40/46).With b values of 800 s/mm2 and 1000 s/mm2,the avemge ADC values of small breast cancers were(1.153±0.192)× 10-3 and(1.079±0.186)× 10-3 mm2/s,while those of benign ones were (1.473±0.252)×10-3 and(1.419±0.255)×10-3 mm2/s,respeetively. There was no significant difference for the ADC values with different b values in the same group(P＞0.05),while there was a signiticant difference between the malignant and the benign lesions(P＜0.05)Thirty-nine of 45 small breast cancers and 19 of 25 small benign breast lesions were correctly diagnosed using DWI with b value of 1000see/mm2.Both the sensitivity and positive predictive value of diagnosis were 86.7%(39/45).The abilities of DWI and DCE MRI for the diagnosis of small breast cancers werle the same. The sensitivity(93.3%)and positive predictive value(91.3%)were improved with the combination of DCE MRI and DWI. Conclusion DWI has a high sensitivity for the detection of small breast cancers,the ADC value can provide valuable information in the differential diagnosis. Key words: Breast neoplasm; Magnetic resonance imaging; Diffusion; Image enhancement