Title: Evaluation of STIR and T2 FAT SAT in bone bruise imaging in occult
scaphoid fracture.
Purpose: To evaluate which sequence - short tau inversion recovery (STIR)
or T2 weighted fat saturation (T2 FAT SAT) – visualizes better bone bruise.
As the study aims at diagnostic quality, in specific size and image quality, the
evaluation is based on measuring area (mm2) and signal intensity (SI) of
different regions of the image.
Methods and Materials: Patients with trauma of the wrist and negative X-ray
image underwent MRI in extremity scanner (General electric, Optima MR
430s, 1.5 T) within 2 weeks after the trauma. Those with a positive sign for
bone bruise both on sagittal T2 FAT SAT and coronal STIR underwent
additional sagittal STIR scanning in sagittal plane through the axis of
scaphoid bone. 51 patients (average: 18.97 years, M: 40, F: 11) met the
inclusion criteria from March 2014 until January 2015.
For the purpose of the study the additional sagittal fast STIR scan was
compared to the sagittal T2 FAT SAT scan. Compared sequences were
executed with equal field of view, number of slices, slice thickness, slice
spacing, NEX, receiver band width, similar signal-to-noise ratio and similar
image acquisition time. On both slices the area of bone bruise was measured
and directly tested for significant difference. SI of bone bruise, SI of the nonaffected bone and both the SI and the standard deviation of the air outside
the image were measured as well in order to calculate image contrast and
contrast-to-noise ratio (CNR) by means of formulae.
All the measurements were taken on the same slices by three readers - two
radiologists with 10 and 8 years of experience in musculoskeletal MRI and
one radiographer with experience in MRI scans and image description.
Results: There was no significant difference comparing bone bruise area
(P=0.50, P=0.50 and P=0.91) or CNR (P=0.16, P=0.31 and P=0.23) on STIR
and T2 FAT SAT. However, image contrast showed significant difference in
favour of T2 FAT SAT in all three readers’ reports (P<0.05, P<0.05 and
P<0.05).
Conclusion: STIR and T2 FAT SAT can be used interchangeably in bone
bruise imaging. However, T2 FAT SAT provides higher image contrast and,
therefore, can be considered as a preferable option when better image
contrast is necessary.