2007 - A technical report of bilateral DCE 3D Breast MRI using mask phase in multi phase function.

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A technical report of bilateral DCE 3D Breast MRI using mask phase in multi phase function.

 

Ho. NamKoong, HM. Kim, WJ. Jung, ES. Kim, KN. Choi, CK. Choi.

Department of diagnostic radiology, Seoul National University Hospital, Seoul, Korea.

 

I. Purpose: Recently advanced volume imaged breast assessment (VIBRANT) has been widely used for morphological and contrast-kinetic information available from the time series of bilateral dynamic contrast enhanced (DCE) 3D breast MR images. We reviewed the technical aspects of VIBRANT with mask phase in multi phase function analyzing reexaminations clinically.

II. Methods & Materials: A total of 489 patients were examined from January to June 2007 in a 1.5T scanner (Signa, HDx, GE, USA) and VIBRANT 8 channel breast array coil. Scan parameters as followings: Pulse sequence; 3D SPGR sagittal plane, TR/TE/Flip=6.7/2.6/10⁰, matrix size: 320ⅹ160, FOV: 18cm, slice thickness/slice number per slab=3mm/80, NEX=1, BW=31.25KHz, scan time: 66sec, ZIP2, ASSET(factor=2), Multi Phase. 0.1mmol/Kg Gadobenate dimeglumine (Mutilhence; Barocco Imaging, Italy) was injected by auto injector with 3~4ml/sec of injection rate and 15ml saline flushing. Dynamic scans (1 pre scan and 3 post scans) were performed with mask phase (166 patients, from Apr 23 to Jun 30) and without mask phase (323 patients, from Jan 1 to Apr 22) in multi phase function. We retrospectively analyzed reexaminations for 6 months comparing dynamic scans between with and without mask phase.

III. Results: Five patients without mask phase underwent reexamination due to mismatch of pre and post contrast shim (Fig1), but only one patient with mask phase have done. All five patients had very tiny breast that could be hard to adjust shim identically in pre and post scan. Owing to only one time pre adjustment scan with mask phase, post contrast scans underwent in the same shimming condition differing from that of without mask phase (Fig 2).

IV. Conclusion: VIBRANT could be very difficult to adjust and easy to change the shim in a very small breast. Some mismatches of pre and post contrast fat shim have often showed in without mask phase, but hardly showed in with mask phase. We suggest that VIBRANT should be used with mask phase in patients with very tiny breast.

 

 

Fig. 1. 3D VIBRANT images acquired in pre (A) and post (B) dynamic contrast enhanced (DCE) and temporal subtraction (C=B-A) of 47-year-old woman with very tiny breast. Fig. 2. DCE images of 44-year-old woman with very tiny breast. Images (A,B) were the same using with mask phase in multi phase function.