Efficacy of 99mTc-DTPA SPECT/CT in diagnosing Orbitopathy in graves’ disease

Abstract

BackgroundThe most frequently used methods of assessing Graves’ orbithopathy (GO) include: Clinical Activity Score (CAS), ultrasonography (USG), computed tomography (CT), and magnetic resonance imaging (MRI). There exists another, slightly forgotten, imaging method: single-photon emission computed tomography (SPECT) with the use of diethylenetriaminepentaacetic acid tagged with 99mTc (99mTc-DTPA). These days it is possible to conduct a SPECT examination fused with a CT scan (SPECT/CT), which increases the diagnostic value of the investigation. The aim of this paper is to evaluate the usefulness of 99mTc-DTPA SPECT/CT in diagnosing Graves orbitopathy, as compared with other methods.MethodsTwenty-three patients with suspected active (infiltrative-edematous) Graves’ orbithopathy were included in the study. Each patient underwent a CAS, an MRI, and a SPECT/CT. The obtained results were analysed statistically, with the assumed statistical significance of p < 0.05.ResultsThe SPECT/CT and MRI were found to have the highest sensitivity: 0.93 each. The SPECT/CT had the highest specificity: 0.89. MRI and CAS had lower values: 0.78 and 0.56, respectively. The occurrence of an active form of GO had no impact on the exacerbation of exophthalmos or the thickness of the oculomotor muscles.ConclusionsThe 99mTc-DTPA SPECT/CT method provides a very good tool for assessing the active form of GO and can, alongside the MRI scan, be used as a referential diagnostic procedure in GO.

Monitoring and Predicting Treatment Response of Extraocular Muscles in Grave's Orbitopathy by 99mTc-DTPA SPECT/CT

“…Orbital CT can provide information on exophthalmos and fat and muscle enlargement, which can be useful for diagnosis. The current study showed that the thickness of four EOMs in the active GO group were greater than those in the inactive GO group and control group, consistent with previous studies ( 13 , 14 ). Additionally, we found that abdominal enlargement of the EOMs, especially the inferior and medial rectus muscles, was most common in GO.…”

“…Thus, our study aimed to evaluate the EOMs of GO using a hybrid SPECT/CT method. SPECT/CT depiction of EOM inflammation may help clinicians to accurately evaluate the inflammatory staging of GO ( 10 , 13 ). Our findings showed that the UR of EOM, especially the medial and inferior rectus muscles, in the active GO group was higher than that in the inactive GO group and the control group, suggesting that the UR has a potential for the evaluation of inflammatory infiltration within EOMs.…”

Lacrimal Gland Measurements in Patients With Graves’ Ophthalmopathy

“…SPECT/CT 0.89. MRI was found to be 0.78 and CAS 0.56 [13]. Evaluation by CAS in patients with long-term GO is not always consistent with retro-orbital activity.…”

Lacrimal Gland Measurements in Patients with Graves’ Ophthalmopathy

“…SPECT+MRI, SPECT/CT, MRI and clinical activity score (CAS) were compared in a study investigating the specifics of diagnostic methods. The specificities of the diagnostic methods were found to be 0.93, 0.89, 0.78, and 0.56, respectively [13] . Evaluation by CAS in patients with long-term GO is not always consistent with retro-orbital activity.…”