Dissertation
Dissertation > Medicine, health > Ophthalmology > Ocular adnexal organ disease

The Application of STIR-FLAIR and T2W-SPIR for Diagnosing the Orbital Lesions: a Contrast Study

Author JiaYuJing
Tutor ShenJunKang
School Suzhou University
Course Medical Imaging and Nuclear Medicine
Keywords magnetic resonance imaging(MRI) inversion recovery(IR) fluid attenuated inversion recovery(FLAIR) short TI inversion recovery(STIR) Spectral Presaturation with Inversion Recovery(SPIR) fat suppression water suppression fat-water suppression
CLC R777
Type Master's thesis
Year 2011
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Purpose: To Combine and compare the images of T2W-SPIR and STIR-FLAIR sequences for the orbit, to evaluate the diagnostic ability of STIR-FLAIR sequence for the orbital lesions, which suppresses signal from both fat and water.Materials and Methods: 51 patients (60 abnormal orbits) and 4 healthy volunteers were recruited for study. All the patients’clinical and MRI data was collected and co-related with the results of pathology and clinical manifestation for accurate diagnosis. Data was evaluated from the transverse images of the STIR-FLAIR and T2W-SPIR sequences though subjective and objective methods and from 6 aspects, such as the appearance of the normal orbit and the adjacent structures, 51 patients(60 abnormal orbits), choroidal lesions, extraocular muscle disease(Graves’disease),optic neuropathy and orbital vascular lesions.Results: 1. The normal orbital and adjacent structures have different appearance in the two sequences, STIR-FLAIR and T2W-SPIR.2. 51 patients(60 abnormal orbits): The interobserver reliability of the lesion scoring, including the quality of the images (artifacts), the lesion visibility and the relationship between lesion and surrounding structures, were assessed using a Kappa test. For the three aspects, STIR-FLAIR sequence’s Kappa values were 0.827, 0.659, 0.645 respectively and for T2W-SPIR sequence they were 0.859, 0.803, 0.807. Compared to the images of T2W-SPIR sequence, STIR-FLAIR sequence’s images had fewer artifacts(two-side P<0.05), higher lesion visibility(two-side P<0.05) and similar ability in assessing the relationship between lesion and surrounding structures(two-side P<0.05). In STIR-FLAIR sequence,the normalized signal intensity(Sn) of normal orbital structures such as orbital fat, orbital preseptal tissues, lacrimal gland and extraocular musles, were all slightly higher than they were in T2W-SPIR sequence(two-side P<0.05 for all of them), but the Sn vitreous body in T2W-SPIR sequence was apparently higher than STIR-FLAIR sequence(two-side P<0.05). In the STIR-FLAIR sequence, the Sn vitreous body was the lowest and the Sn extraocular muscles were the highest(two-side P<0.05 for all the comparisons) while comparing with other normal structures. By contrast, in the T2W-SPIR sequence the Sn vitreous body was the highest and the Sn extraocular muscles were similar to the Sn lacriaml gland with two-side P>0.05 while comparing with other normal structures. For the Sn lesions, they were higher than Sn extraocular muscles in STIR-FLAIR sequence while apparently lower than Sn vitreous body(two-side P<0.05 for all the comparisons). And, the STIR-FLAIR sequence had bigger signal intensity ratio(R)between the lesions and the vitreous body(two-side P<0.05), while the Rlesions/orbital fat was bigger in T2W-SPIR sequence with two-side P<0.05.3. Choroidal lesions: For this kind of disease, STIR-FLAIR sequence’s images had lighter artifact, higher lesion visibility and higher ability in assessing the relationship between lesion and surrounding structures(two-side P<0.05 for all the three subjective assessments’comparisons). In STIR-FLAIR sequence, the Sn lesions were higher than both Sn orbital fat and Sn vitreous body with two-side P<0.05 for the both of them. In T2W-SPIR sequence, the Sn lesions and the Sn vitreous body were both higher than Sn orbital fat(two-side P<0.05 for both of them). Rlesions/ vitreous body in STIR-FLAIR sequence was bigger than in T2W-SPIR sequence(two-side P<0.05).4. Extraocular muscle disease(Graves’disease): All the 11 abnormal extraocular muscles were diagnosed by both of the two sequences. The outline of the 11 abnormal extraocular musles were displayed clearer in STIR-FLAIR sequence than T2W-SPIR sequence,while high signal around some abnormal extraocular muscles showed in T2W-SPIR sequence could not been seen in STIR-FLAIR sequence. In STIR-FLAIR sequence, the Sn abnormal extraocular muscles were higher than Sn normal extraocular muscles, Sn orbital fat and Sn vitreous body with two-side P<0.05 for all of them. In T2W-SPIR sequence, the Sn vitreous body were higher than Sn abnormal extraocular muscles, Sn normal extraocular muscles and Sn orbital fat(two-side P<0.05 for all of them). R abnormal extraocular muscles / vitreous body in STIR-FLAIR sequence was apparently bigger than in T2W-SPIR sequence(two-side P<0.05), and the R abnormal extraocular muscles / normal extraocular muscles in STIR-FLAIR sequence was slightly bigger than in T2W-SPIR sequence(two-side P<0.05) .While the R abnormal extraocular muscles /orbital fat between the two sequences were no significant different(two-side P>0.05).5. Optic neuropathy: The abnormal appearances of the 3 optic atrophy and 1 optic nerve violated by acute promyelocytic leukemia were displayed better in STIR-FLAIR sequence than in the T2W-SPIR sequence.6. Orbital vascular lesions: The two sequences had similar lesion visibility and the similar capability in assessing the relationship between the lesion and surrounding structures(two-side P>0.05 for both of them). In the STIR-FLAIR sequence, the Sn lesions were higher than Sn orbital preseptal tissues, Sn orbital fat and Sn vitreous body with two-side P<0.05 for all of them. In T2W-SPIR sequence, the Sn vitreous body were higher than Sn orbital preseptal tissues, Sn orbital fat and Sn lesions (two-side P<0.05 for all of them). Rlesions/ vitreous body in STIR-FLAIR sequence was bigger than in T2W-SPIR sequence(two-side P<0.05),while the Rlesions/orbital fat was bigger in T2W-SPIR sequence(two-side P<0.05).Conclusion: While imaging the orbit, compared with T2W-SPIR sequence, STIR-FLAIR sequence’s images have fewer artifacts, higher tissue signal intensity contrast and higher lesion visibility. For the diseases which are related with choroid, STIR-FLAIR sequence is better than T2W-SPIR sequence not only in depicting but also in assessing the lesion range. For the optic neuropathy, the STIR-FLAIR sequence may be better too. For the extrocular abnormality of active Graves’disease, STIR-FLAIR sequence may be better than T2W-SPIR sequence owing to the better display for the outline of the abnormal extraocular, but for the inflammatory tissues’depiction, the T2W-SPIR sequence is better. For the orbital vascular lesions’diagnose, they have no different. To sum up, we recommend that STIR-FLAIR sequence has many benefits, especially when suspecting the lesions related with the eyeball(globe) and optic nerve, and when imaging these kinds of disease, STIR-FLAIR can take palce of T2W-SPIR sequence.

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