Comparison of T1 FLAIR and T1 FSE Images Andrew Allmendinger, DO Sylvie Destian, MD

 Neither I nor my immediate family members have a financial relationship with commercial organizations that may have a direct or indirect interest in the content of this presentation.

 In most institutions, a sagittal T1 FLAIR sequence has replaced the T1 FSE in routine MR imaging of the lumbar spine.

 Faster  Provides better conspicuity of abnormalities in the cord, CSF, disc, and bone 1,2,3. 1 Erdem LO, Erdem CZ, Acikgoz B, Gundogdu S. Degenerative disc disease of the lumbar spine: a prospective comparison of fast T1-weighted fluid- attenuated inversion recovery and T1-weighted turbo spin echo MR imaging. Eur J Radiol, 2005 Aug; 55(2): Lavdas E, Vlychou M, Arikidis N, Kapsalaki E, Roka V, Fezoulidis IV. Comparison of T1 weighted fluid-attenuated inversion recovery images of the lumbar spine at 3.0 Tesla. Acta Radiol 2010 Apr; 51(3): Melhem ER, Israel DA, Eustace S, Jara H. MR of the spine with a fast T1-weighted fluid-attenuated inversion recovery sequence. AJNR 1997 Mar;18:

 T1 FLAIR = T1 FSE?  To determine whether there is a difference in the appearance of the marrow signal on T1 FLAIR and T1 FSE images in normal individuals  To determine whether the difference is related to age.

 Sagittal T1 FLAIR  TE 22, TI 500, TR 2000, Echo Train 12, Freq 448, Phase 224, NEX 2, Slice thickness 4/1, Freq encoding A/P, imaging options: NPW, scan time 2:16  Sagittal T1 FSE  TE minimum full, TR 650, Echo Train 2, Freq 256, Phase 192, NEX 2, Slice thickness 4/1, Freq encoding A/P, imaging options: FC, NPW, TRF, FAST, scan time 3:14

 1.5T GE Signa /Excite  Prospective study  All patients having non contrast MRI of the lumbar spine during a 3 month period in 2009 (n=217).

 Exclusion criteria:  older than 75 years  prior lumbar surgery  predisposing medical condition  HIV disease  multiple myeloma  osteoporosis  metastatic disease  renal failure  severe degenerative disease  Final n=93

A midline sagittal T1 FLAIR and T1 FSE image from each exam, randomly labeled “A” or “B”, were placed side by side in a power point presentation. B A

 All case pairs were reviewed by 3 board certified radiologists, each with more than 5 years experience in MR imaging.  The radiologists compared the two images and were asked whether  marrow signal intensity = or difference perceived?  T1 FLAIR or T1 FSE darker?

The marrow signal intensity appears lower on the T1 FLAIR image (A), compared to the T1 FSE image (B) on the right. A B

The marrow signal intensity appears lower on the T1 FSE image (A) compared to the T1 FLAIR image (B) on the right. B A

The marrow signal intensity on the T1 FSE image (A) and the T1 FLAIR image (B) appears equal. AB

AgeT1 FLAIR Darker T1 FSE Darker 0 to to to to to to to to Total (n=70)5416 Where a difference was perceived, the marrow signal intensity was judged darker on T1 FLAIR 77% of the time (p <.0001).

AgeT1 FLAIR Darker T1 FSE Darker 0 to to to to to to to to 7540 Total (n=35)323 Where a difference was perceived, the marrow signal intensity was judged darker on T1 FLAIR 91% of the time (p < ).

AgeT1 FLAIR Darker T1 FSE Darker 0 to to to to to to to to Total (n=87)852 Where a difference was perceived, the marrow signal intensity was judged darker on T1 FLAIR 98% of the time (p <.0001).

 T1 FLAIR and T1 FSE were judged equal in 31% of the cases.  When a difference was perceived, the T1 FLAIR image was judged darker in 88% of the cases.  T1 FLAIR was judged darker in all age groups from

 1 patient < 20 years  One radiologist  T1 FLAIR darker  Two radiologists  T1 FLAIR = T1 FSE  More data needed 0-20 age group

 Regardless of age, marrow signal intensity on T1 FLAIR images may appear artificially low in normal individuals.  It is important to recognize this potential pitfall in order to avoid misdiagnoses and/or additional unnecessary exams.