Rofo 2005; 177 - 21
DOI: 10.1055/s-2005-865270

Ultra-fast MR imaging of the female plevis at 3.0 T with with Sense and FAS

N Morakkabati-Spitz 1, J Gieseke 2, CK Kuhl 1, G Lutterbey 1, M von Falkenhausen 1, F Träber 1, O Zivanovic 2, HH Schild 1
  • 1Department of Radiology, University of Bonn, Germany
  • 2Philips Medical Systems, Best, The Netherlands
  • 3Department of Gynecology and Obstetrics, University of Bonn

Purpose: The increase in signal-to-noise (SNR) at 3.0 Tesla allows to either increase spatial resolution or to shorten scan time.

In this study we investigated 3.0 T's potential for the development of an ultra-fast T2-weighted TSE pulse sequence (3T-FAST) for MR imaging of the female pelvis. Aim was to find out if this pulse sequence maintained diagnostic image quality as compared to a standard pulse sequence and allowed for clinically useful pelvic MR imaging.

Methods: 3T-FAST was designed as single-shot T2-weighted TSE-pulse-sequence which -in order to reduce energy deposition at 3.0T- was combined with SENSE (SF3) and Flip angle sweep technique (FAS 75°). The use of FAS 75° required an adaptation of the contrast parameters (TR/TE 4933/100 ms). Spatial resolution (0.7×1.0×4mm) was kept identical as compared to a standard protocol (3T-SP, which has schown to be equivalent to 1.5 T in a prior study) whereas scan time was drastically reduced to 39s with 3T-FAST.

We performed a prospective intraindividual comparative trial on 17 patients who were examined twice at 3.0 T within on day in a randomized order.

Patients were referred with the suspicion of carcinoma of the cervix (n=2), ovarian tumors (n=5), myomas (n=5), uterine malformation (n=1) unclear abdominal pain (n=3) and pelvic metastasis (n=1). I.v. n-butyl-scopolamine was given to all patients prior to the study in order to reduce peristalsis.

Two radiologists analyzed the examinations in consensus with regard to tissue contrast (visualization of zonal anatomy of the uterus and/or delineation of pathologic findings) rated on a 3 point-scale (3=3T-FAST better; 2=3T-FAST equal; 1=3T-FAST worse than 3T-SP). In addition, we performed quantitative contrast measurements. Analysis of image quality comprised level of artifacts (rated on a five point scale: 1=no artifacts; 5=non-diagnostic study), visual signal to noise ratio (rated on a 3 point scale) and detail delineation (rated on a 3 point scale).

Results: 3T-FAST was technically succesful for all 17/17 cases. All 17/17 3T-FAST MRI studies were of diagnostic image quality. Motion artifacts were significantly reduced with 3T-FAST as compared to 3T-SP (p<10-3). The qualitative contrast analysis revealed comparable contrasts for the zonal anatomy, between solid tumors and muscle and cystic tumors and muscle whereas 3T-FAST showed significantly higher contrast between bladder and muscle as well between ovarian cysts and ovarian stroma as compared to 3T-SP. The quantitative analysis confirmed these findings. The delineation and detectability of pathological disorders was rated equal for 3T-FAST and 3T-SP. Final MR imaging diagnoses were identical for all 17/17 patients.

Conclusion: FAS und SENSE allow for ultra-fast MR imaging at 3.0T maintaing the diagnostic confidence as provided by a standard pulse sequence. Therefore, 3T-FAST seems to be advantageous for pelvic MR imaging of incooperative patients (and possibly patients with contraindications for i.v. n-butyl-scopolamine).