Turbo Gradient and Spin Echo PROPELLER-Diffusion Weighted Imaging for Orbital Tumors: A Comparative Study With Readout-Segmented Echo-Planar Imaging

Turbo Gradient and Spin-Echo BLADE-DWI for Extraocular Muscles in Thyroid-Associated Ophthalmopathy

Purpose: To investigate feasibility and diagnostic performance of turbo gradient and spin-echo BLADE (proprietary name for Periodically Rotated Overlapping ParallEL Lines with Enhanced Reconstruction [PROPELLER] in Siemens MR systems)-diffusion weighted imaging (TGSE-BLADE-DWI) for depicting extraocular muscle (EOM) involvement and activity in thyroid-associated ophthalmopathy (TAO), and to compare TGSE-BLADE-DWI with readout-segmented echo-planar imaging (RESOLVE). Materials and methods: Thirty-five patients with identified TAO underwent the two DWI scans. Two radiologists visually scored the image quality of the two DWIs with respect to the susceptibility artifacts and geometric distortions on a three-point scale. The maximum size (Size_max) of EOMs and corresponding ADCs (cADCs) of each patient were compared between the active and inactive phases. The clinical activity score (CAS) was used as a reference to assess the diagnostic performance of EOM ADCs for grading TAO activity. ROC analysis, Pearson correlation, and Wilcoxon signed-rank test were used for statistical analyses. Results: For scores of EOMs, the image quality of TGSE-BLADE-DWI was significantly higher than that of RESOLVE. There were no statistically significant differences between the AUCs of the two DWIs, Size_max, or cADCs between the active and inactive phases. TGSE-BLADE-DWI ADCs were significantly higher than the RESOLVE ADCs in the right superior rectus, right lateral rectus, left superior rectus, and left inferior rectus. There were no statistically significant correlations between the cADC or Size_max, and CAS. The highest AUC was 0.697 for RESOLVE and 0.657 for TGSE-BLADE-DWI. The best performing ADC threshold was 1.85 × 10^-3 mm²/s with 85.7% sensitivity, 58.8% specificity and 66.67% accuracy for RESOLVE and 1.99 × 10^-3 mm²/s with 79.0% sensitivity, and 55.6% specificity and 65.27% accuracy for TGSE-BLADE-DWI. Conclusion: Compared to RESOLVE, TGSE-BLADE-DWI provided improved image quality with fewer susceptibility artifacts and geometric distortions for EOM visualization and showed an equivalent performance in detecting active TAO.

Comparison of TGSE-BLADE DWI, RESOLVE DWI, and SS-EPI DWI in healthy volunteers and patients after cerebral aneurysm clipping

Diffusion-weighted magnetic resonance imaging is prone to have susceptibility artifacts in an inhomogeneous magnetic field. We compared distortion and artifacts among three diffusion acquisition techniques (single-shot echo-planar imaging [SS-EPI DWI], readout-segmented EPI [RESOLVE DWI], and 2D turbo gradient- and spin-echo diffusion-weighted imaging with non-Cartesian BLADE trajectory [TGSE-BLADE DWI]) in healthy volunteers and in patients with a cerebral aneurysm clip. Seventeen healthy volunteers and 20 patients who had undergone surgical cerebral aneurysm clipping were prospectively enrolled. SS-EPI DWI, RESOLVE DWI, and TGSE-BLADE DWI of the brain were performed using 3 T scanners. Distortion was the least in TGSE-BLADE DWI, and lower in RESOLVE DWI than SS-EPI DWI near air-bone interfaces in healthy volunteers (P < 0.001). Length of clip-induced artifact and distortion near the metal clip were the least in TGSE-BLADE DWI, and lower in RESOLVE DWI than SS-EPI DWI (P < 0.01). Image quality scores for geometric distortion, susceptibility artifacts, and overall image quality in both healthy volunteers and patients were the best in TGSE-BLADE DWI, and better in RESOLVE DWI than SS-EPI DWI (P < 0.001). Among the three DWI sequences, image quality was the best in TGSE-BLADE DWI in terms of distortion and artifacts, in both healthy volunteers and patients with an aneurysm clip.

Accuracy of 2D BLADE Turbo Gradient- and Spin-Echo Diffusion Weighted Imaging for the Diagnosis of Primary Middle Ear Cholesteatoma

OBJECTIVE

To evaluate the diagnostic accuracy of 2D BLADE turbo gradient- and spin-echo diffusion weighted imaging (TGSE BLADE DWI) for primary middle ear cholesteatoma diagnosis, using qualitative and quantitative methods.

STUDY DESIGN

Retrospective case series.

SETTING

University hospital.

PATIENTS

Participants included those with suspected primary middle ear cholesteatoma after assessment by clinical otorhinolaryngologists combined with magnetic resonance imaging (MRI) examination. Finally, of the 85 ears from 65 patients enrolled in the study, 73 had cholesteatoma, and 12 had otitis media.

INTERVENTION

Two radiologists independently assessed images and measured apparent diffusion coefficient (ADC) values. Sensitivity, specificity and accuracy were evaluated. Kappa (k) statistics, the intraclass correlation coefficient (ICC), the Kolmogorov-Smirnov normality test, the independent t test, and receiver operating characteristic (ROC) analysis were used for statistical analysis. Pair-wise comparison of the area under the ROC curve (AUC) was also performed using the Delong test.

MAIN OUTCOME MEASURES

Imaging and histopathologic findings.

RESULTS

The mean ADC value of cholesteatoma group (mean, 0.923 ± 0.246 × 10 -3 mm 2 /s) was significantly lower than that of noncholesteatoma group (mean, 1.744 ± 0.205 × 10 -3 mm 2 /s; p < 0.001). In ≤3 mm cholesteatoma group, the AUC of qualitative DWI was 0.846; the sensitivity, specificity, and accuracy for diagnosing cholesteatoma were 69.23%, 100%, and 84%, respectively; while the AUC of quantitative diagnosis was significantly increased to 1.0 ( p = 0.0209); and based on the optimal threshold of ADC, ≤1.352 × 10 -3 mm 2 /s, the sensitivity, specificity and accuracy improved to 100%. For >3 mm cholesteatoma group, there were no significant differences in diagnostic performance. Excellent interobserver agreement and ICC for the qualitative and quantitative evaluations (k = 0.90 and ICC = 0.80, respectively) was noted between reviewers.

CONCLUSION

TGSE BLADE DWI is useful for the detection of primary middle ear cholesteatomas, especially ≤3 mm lesions.

Detection of cholesteatoma: 2D BLADE turbo gradient- and spin-echo imaging versus readout-segmented echo-planar diffusion-weighted imaging

PURPOSE

This study is to compare the accuracy of 2D BLADE turbo gradient- and spin-echo imaging (TGSE BLADE) diffusion-weighted imaging (DWI) with that of readout-segmented echo-planar (RESOLVE) DWI in the detection of primary and residual/recurrent temporal bone cholesteatoma.

METHODS

The prospective study population consisted of 58 patients who were underwent magnetic resonance (MR) imaging for the evaluation of suspected temporal bone cholesteatoma. Two radiologists independently evaluated the two sequences. Kappa (k) statistics, the intra-class correlation coefficient (ICC), and a paired t test were used for statistical analysis.

RESULTS

Of the 58 patients included, all had histo-pathologically confirmed cholesteatomas. In ≤ 3 mm group (n = 13), TGSE BLADE sequence correctly identified all cases except one that was recorded as equivocal on both sequences because of high signal intensity on T1WI; while on RESOLVE sequences, 6 were positive, 4 were equivocal, and 3 were false negative. For > 3 mm group (n = 45), detection performance was similar between the two sequences. The mean ADC of cholesteatoma on TGSE BLADE DWI was 0.923 × 10^-3 mm²/s, and the mean ADC of cholesteatoma on RESOLVE DWI was 0.949 × 10^-3 mm²/s, with no significant difference in the mean ADC values of cholesteatoma measured on the two sequences (p = 0.9216).

CONCLUSION

TGSE BLADE outperforms RESOLVE in the detection of small temporal bone cholesteatoma ≤ 3 mm.