Objective To assess the value of susceptibility weighted imaging (SWI)in the diagnosis of different cerebral diseases complicated with cerebral microbleeds (CVBs)and cerebral vascular malformations (CVMs).Methods The MRI data of 76 cases with CMBs and 25 cases with CVMs were retrospectively analyzed and the data were translated as follows:(1 )To compare the counts and detecting sensitivity of CMBs on routine MRI sequences (T1 WI,T2 WI,T2 FLAIR,DWI)with SWI.(2)To assess the difference of SWI,MIP and Phase in detecting the size,counts,intensity and edge features of CMBs.(3)To assess the advantages of SWI in the diagnosis of different CVMs.Results (1)In all 1 524 CMBs detected on SWI,294,87,361,391 CMBs were detected on T1 WI,T2 WI,T2 FLAIR and DWI respectively.The sensitivities were 19.3%,5.7%,23.7% and 5.7% on T1 WI,T2 WI,T2 FLAIR and DWI respectively.It was of statistical significance (P <0.05)in the counts and detecting sensitivity on different MRI sequences.(2) 1 524 and 1 539 CMBs were detected on SWI and MIP respectively.CMBs showed oval,dotted hypointensity or hypointensity domi-nated mixed intensity lesions which were ≤10 mm in size on SWI and MIP.1 521 CMBs were detected on Phase,which appeared as hyperintensity or hyperintensity dominated mixed intensity lesions.MIP and SWI were similar in detecting the size,counts and edge features of CMBs.And Phase was inferior compared with MIP and SWI .(3)12 cases of cerebral venous malformation were detec-ted,which all appeared as the classic Medusa head sign on SWI.6 cases of intracerebral capillary telangiectasia were detected , which were characterized as multiple small rounded even hypointense lesions ortarget signon SWI .2 cases of arteriovenous malformation (AVM)were detected on SWI,in which one case only showed multiple small vessels and gross drainage vein,and the other showed clear nidus and gross drainage veins into the sigmoid sinus.4 cases of cerebral cavernous angioma were detected.Mulberry sign, which was characterized as dotted mixed intensity lesion with hypointense ring,was noted in all the cases on SWI.One case of Sturge-Weber syndrome was detected,which showed gyriform low signal lesion on MIP imaging.And many broadened,tortuous veins in the cerebral hemispheres and near the tentorium were also noted.Conclusion SWI can be used as an important sequence for detecting CMBs.Different CVMs show their specific signs in SWI sequence.Combined with conventional MRI sequences an accurate diagnosis can be achieved most of the time.