Interobserver and intraobserver reliability of skull base angles measured on magnetic resonance images

BACKGROUND Determination of platybasia and basilar kyphosis are significant parts of routine cranial magnetic resonance(MR)interpretations.These situations may explain a patient’s symptoms or may be associated with other anomalies.AIM To indicate the interobserver and intraobserver reliability of the skull base angles(SBA)(Koenigsberg standard)and modified SBA(mSBA)measurement techniques.METHODS In total,391 patients who had undergone cranial MR imaging were re-assessed regarding the SBA measurements.The SBA and mSBA techniques were used on MR images.Two reviewers independently measured the same angles twice within a 15-day interval,using different monitors.Intraclass correlation coefficient(ICC)was calculated to reveal the intraobserver and interobserver agreements.RESULTS There was an excellent agreement between reviewers regarding both angle measurements(ICC was 0.998 for SBA and mSBA).Excellent agreement levels were also observed for intraobserver measurements.ICC was 0.998 for SBA and 0.999 for mSBA for reviewer 1.ICC was 0.997 for SBA and 0.999 for mSBA according to the measurement results of reviewer 2.Higher SBA and mSBA values were observed for females compared to males.There was no correlation between SBA and age for SBA.However,a negative and low-level correlation was observed between mSBA values and age for both reviewers.CONCLUSION SBA and mSBA measurements indicated excellent agreement regarding interobserver and intraobserver differences.The study results showed that SBA angles were reliable measurement techniques to be used on MR images.

Identification and Localization of Prostate Cancer with Combined Use of T2-Weighted,Diffusion Weighted MRI and Proton MR Spectroscopy,Correlation with Histopathology

Purpose: To predict the diagnostic performance of combined use of T2-weighted imaging (T2W)-diffusion weighted MRI (DWI) and apparent diffusion coefficient (ADC)-proton MR spectroscopy (H-MRS) for the detection of prostate cancer, correlated to histopathology as the reference standard. Method: After institutional review board approval, 40 patients with prostate cancer were included in this retrospective research. Two readers evaluated the results of T2W, DWI-ADC mapping and H-MRS independently for the depiction of prostate cancer. Reference standard was the TRUS-guided biopsy and the surgical histopathological results. Statistical analysis was assessed by Fisher’s exact t-test, Wilcoxon signed rank test, variance analysis test with Kappa (k) values and receiver operating characteristics (ROC) curve for ADC values, Cho/Cit and Cho + Cre/Cit ratios for each observer. Results: Both readers declined 46% sensitivity and 68% specificity for T2W sequence, 29% sensitivity and 82% specificity for DWI-ADC mapping and 49% specificity for Cho/Cit and Cho + Cre/Cit ratios, 69% sensitivity for Cho/Cit 70% sensitivity for Cho + Cre/Cit ratios of H-MRS. T2W + DWI-ADC mapping + H-MRS (Cho/Cit and Cho + Cre/Cit ratios) regarded 81% sensitivity and 66% specificity, with significant statistical differences to the reference histopathology (p 0.05). Conclusion: Combination of T2W, DWI and H-MRS were more sensitive and more accurate than either sequences alone, for prostate cancer localization and detection.