Limited role of gadolinium to detect active sacroiliitis on MRI in juvenile spondyloarthritis

OBJECTIVE: The aim of this study is to determine the added diagnostic value of contrast-enhanced (CE) magnetic resonance imaging (MRI) compared to routine non contrast-enhanced MRI to detect active sacroiliitis in clinically juvenile spondyloarthritis (JSpA). MATERIALS AND METHODS: A total of 80 children clinically suspected for sacroiliitis prospectively underwent MRI of the sacroiliac (SI) joints. Axial and coronal T1-weighted (T1), Short-tau inversion recovery (STIR) and fat-saturated T1-weighted gadolinium-DTPA (Gd) contrast-enhanced (T1/Gd) sequences were obtained. The presence of bone marrow edema (BME), capsulitis, enthesitis, high intra-articular STIR signal, synovial enhancement and a global diagnostic impression of the MRI for diagnosis of sacroiliitis was recorded. RESULTS: STIR and T1/Gd sequences had 100 % agreement for depiction of BME, capsulitis and enthesitis. High intra-articular STIR signal was seen in 18/80 (22.5 %) patients, 15 (83 %) of whom also showed synovial enhancement in the T1/Gd sequence. Sensitivity (SN) and specificity (SP) for a clinical diagnosis of JSpA were similar for high STIR signal (SN = 33 %, SP = 85 %) and T1/Gd synovial enhancement (SN = 36 %, SP = 92 %). Positive likelihood ratio (LR+) for JSpA was twice as high for synovial enhancement than high STIR signal (4.5 compared to 2.2). Global diagnostic impression was similar (STIR: SN = 55 %, SP = 87 %, LR + =4 .2; T1/Gd: SN = 55 %, SP = 92 %, LR + = 6.9). CONCLUSION: MRI without contrast administration is sufficient to identify bone marrow edema, capsulitis and retroarticular enthesitis as features of active sacroiliitis in juvenile spondyloarthritis. In selected cases when high STIR signal in the joint is the only finding, gadolinium-enhanced images may help to confirm the presence of synovitis

Potential heating effect in the gravid uterus by using 3-T MR imaging protocols: Experimental study in miniature pigs

Purpose: To determine the changes in temperature within the gravid miniature pig uterus during magnetic resonance (MR) imaging at 3 T. Materials and Methods: The study received ethics committee approval for animal experimentation. Fiber-optic temperature sensors were inserted into the fetal brain, abdomen, bladder, and amniotic fluid of miniature pigs (second trimester, n = 2; third trimester, n = 2). In the first trimester (n = 2), the sensors were inserted only into the amniotic fluid (three sacs per miniature pig, for a total of six sacs). Imaging was performed with a 3-T MR imager by using different imaging protocols in a random order for animal, each lasting approximately 15 minutes. The first regimen consisted of common sequences used for human fetal MR examination, including normal specific absorption rate (SAR). The second regimen consisted of five low-SAR sequences, for which three gradient-echo sequences were interspersed with two diffusion-weighted imaging series. Finally, a high-SAR regimen maximized the radiofrequency energy deposition (constrained by the 2-W per kilogram of body weight SAR limitations) by using five single-shot turbo spin-echo sequences. Differences in temperature increases between the three regimens and between the three trimesters were evaluated by using one-way analysis of variance. The maximum cumulative temperature increase over 1 hour was also evaluated. Results: Low-SAR regimens resulted in the lowest temperature increase (mean ± standard deviation, 20.03°C ± 0.20), normal regimens resulted in an intermediate increase (0.31°C ± 0.21), and high-SAR regimens resulted in the highest increase (0.56°C ± 0.20) (P <.0001). Mean temperature increase in the third trimester was 0.38°C ± 0.27, with no significant differences compared with the first (0.23°C ± 0.27) and second (0.25°C ± 0.32) trimesters (P = .07). The cumulative temperature increase over 1-hour imaging time with high SAR can reach 2.5°C. Conclusion: In pregnant miniature pigs, the use of 3-T magnets for diagnostic MR imaging with normal SAR regimens does not lead to temperature increases above 1°C if imaging time is kept below 30 minutes. Longer imaging time, especially with high-SAR regimens, can lead to an increase of 2.5°C.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Congenital cytomegalovirus infection: contribution and best timing of prenatal MR imaging

Objective: To predict sensorineural hearing loss (SNHL) and neurological impairment in congenital cytomegalovirus (cCMV) infection using MR imaging and define the best timing in pregnancy for prenatal assessment. Methods: In 121 patients with confirmed cCMV infection, brain features at MR imaging were respectively graded from 1 to 5: normal; isolated frontal/parieto–occipital hyperintensity; temporal periventricular hyperintensity; temporal/occipital cysts and/or intraventricular septa; migration disorders. Grading was correlated with postnatal SNHL and neurological impairment using regression analysis. In 51 fetuses with MR examinations at 26.9 and 33.0 weeks, the predictive value of SNHL and neurological impairment was compared using ROC curves. Results: Postnatal follow-up showed SNHL in 18 infants and neurological impairment in 10. MR grading was predictive of SNHL and of neurological impairment (P < 0.001). In grade 1 or 2, none had SNHL and 1/74 had neurological impairment. The areas under ROC curves for prediction of postnatal SNHL and of neurological impairment from first and second MR examination were comparable. Conclusion: Our data suggest that in cCMV infection, prediction of SNHL and neurological impairment is feasible by fetal MR imaging with a high negative predictive value and can equally be done at 27 or 33 weeks of gestation. Key points: • In cCMV, isolated periventricular T2-weighted signal hyperintensity has a good postnatal prognosis. • In cCMV, SNHL and neurological impairment can be predicted at 27 or 33 weeks. • In cCMV, fetal MR has a high NPV in predicting SNHL. • In cCMV, fetal MR has a high NPV in predicting neurological impairment.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

Congenital cytomegalovirus infection: contribution and best timing of prenatal MR imaging

To predict sensorineural hearing loss (SNHL) and neurological impairment in congenital cytomegalovirus (cCMV) infection using MR imaging and define the best timing in pregnancy for prenatal assessment.status: publishe