Exploratory study of the interest of MR susceptibility-weighted imaging for the pre-operative assessment of pelvic endometriosis extent.

OBJECTIVE: To evaluate the performance of magnetic resonance imaging (MRI) with susceptibility-weighted imaging (SWI) in the assessment of endometriosis. MATERIAL AND METHODS: This prospective study was performed during the diagnostic step or the pre-operative assessment of endometriosis, between June 2017 and April 2018. The MRI was conducted with a 3T MRI device; protocol included T2W, T1W, with and without fat-saturation sequences completed with a SWI sequence: T2-star weighted angiography (SWAN). The diagnostic performance values of MRI and inter-observer agreement were first evaluated with a conventional MR protocol and then with the complementary SWAN sequence by 2 readers. MRI results were correlated with surgical findings in patients who underwent laparoscopy. RESULTS: 74 patients were included in the study, and among them 10 patients were treated by laparoscopy. 81% of the endometriosis lesions had signal losses on the SWAN sequence related to hemorrhagic character whereas only 52% of the lesions had T1-weighted hyperintense implants. Diagnostic performance of the MRI examination was improved by the use of the SWAN sequence compared to the conventional MR protocol (Se = 94% and Spe = 73% in complete protocol and Se = 88% and Spe = 69% in conventional protocol), especially for the involvement of torus uterinus, utero-sacral ligament and retro-cervical site. An excellent interobserver agreement (қ-value = 0,94) was noted between the two readers. CONCLUSION: SWI can improve the diagnostic accuracy of MRI by allowing the detection of hemorrhagic character of endometriosis lesions.

Correction to: Diagnostic performance of an unenhanced MRI exam for tumor follow-up of the optic pathway gliomas in children.

In the article "Diagnostic performance of an unenhanced MRI exam for tumor follow-up of the optic pathway gliomas in children", Table 2 data were not presented correctly, with results placed beneath an incorrect heading. Confidence interval also added. The original article has been corrected.

Diagnostic performance of an unenhanced MRI exam for tumor follow-up of the optic pathway gliomas in children.

PURPOSE: Contrast-enhanced MRI (MRI + C) is considered as mandatory for brain tumors follow-up, but gadolinium brain depositions in relation with repeated injections have been reported. The aim of our work was to evaluate the diagnostic performance of an unenhanced MRI examination for the follow-up of optic pathway gliomas (OPG) in children. METHODS: Seventeen patients (with/without NF1) were selected from 2001 to 2017, with at least 5 MRI + C brain follow-up examinations. Privacy and data protection rights were addressed by the data protection officer (DPO) and the study was in accordance with the local ethical rules. Twenty-five cases of tumor progression and 25 cases of tumor stability mentioned in the conclusion of radiological reports (defined as gold standard) were isolated. Those exams were anonymized and independently reviewed by two radiologists, who analyzed both quantitative (such as tumor volume variation) and qualitative criteria (such as ventricular dilatation) on unenhanced images. Sensitivity, specificity, positive/negative predictive values (PPV, NPV), and inter/intra-observer agreement were calculated. RESULTS: The mean age of patients was 5.4 ± 3.4 years and mean follow-up length 6.7 years. The mean number of MRI + C was 13.5 (SD 7.2). The sensitivity of unenhanced MRI for tumor follow-up was 84-88% (95% CI 63.9-97.5). The specificity was 91.3-100% (95% CI 72-100). The PPV was 91.7% for reader 1 and 100% for reader 2. The NVP was 87.5% for reader 1 and 85.2% for reader 2. There was an excellent inter-observer agreement regarding tumor progression: kappa coefficient of 0.87 (p < 0.001). Inter/intra-variability for percentage of tumor volume variation between two exams were good (correlation coefficients of 0.97 and 0.94). CONCLUSION: Tumor volume variation is in most cases sufficient to assess OPG progression. Systematic MRI + C could be questionable.

Lung morphology assessment of cystic fibrosis using MRI with ultra-short echo time at submillimeter spatial resolution.

OBJECTIVES: We hypothesized that non-contrast-enhanced PETRA (pointwise encoding time reduction with radial acquisition) MR (magnetic resonance) sequencing could be an alternative to unenhanced computed tomography (CT) in assessing cystic fibrosis (CF) lung structural alterations, as well as compared agreements and concordances with those of conventional T1-weighted and T2-weighted sequences. MATERIAL AND METHODS: Thirty consecutive CF patients completed both CT and MRI the same day. No contrast injection was used. Agreement in identifying structural alterations was evaluated at the segmental level using a kappa test. Intraclass correlation coefficients (ICC) and Bland-Altman analysis were used to assess concordances and reproducibility in Helbich-Bhalla disease severity scoring. RESULTS: Agreement between PETRA and CT was higher than that of T1- or T2-weighted sequences, notably in assessing the segmental presence of bronchiectasis (Kappa = 0.83; 0.51; 0.49, respectively). The concordance in Helbich-Bhalla scores was very good using PETRA (ICC = 0.97), independently from its magnitude (mean difference (MD) = -0.3 [-2.8; 2.2]), whereas scoring was underestimated using both conventional T1 and T2 sequences (MD = -3.6 [-7.4; 0.1]) and MD = -4.6 [-8.2; -1.0], respectively). Intra- and interobserver reproducibility were very good for all imaging modalities (ICC = 0.86-0.98). CONCLUSION: PETRA showed higher agreement in describing CF lung morphological changes than that of conventional sequences, whereas the Helbich-Bhalla scoring matched closely with that of CT. KEY POINTS: • Spatial resolution of lung MRI is limited using non-ultra-short TE MRI technique • Ultra-short echo time (UTE) technique enables submillimeter 3D-MRI of airways • 3D-UTE MRI shows very good concordance with CT in assessing cystic fibrosis • Radiation-free 3D-UTE MRI enables the Helbich-Bhalla scoring without a need for contrast injection.