Diagnostic Accuracy of Standalone T2 Dixon Sequence Compared with Conventional MRI in Sacroiliitis

Aim  The aim of this article was to assess the profile of T2-weighted (T2W) multipoint Dixon sequence and conventional sequences in magnetic resonance imaging (MRI) of sacroiliac joints for the diagnosis of active and chronic sacroiliitis.

Settings and Design  Prospective observational study.

Materials and Methods  Thirty-seven patients with sacroiliitis underwent MRI with conventional coronal oblique short tau inversion recovery, T1W sequences, and T2W multipoint Dixon sequences. T1 fat-saturated postcontrast sequences were added in active cases. Comparisons were made between conventional and T2 Dixon sequences both quantitatively and qualitatively.

Statistical Analysis  Paired t -test was used to study the difference in contrast–noise ratio (CNR) between two groups. Chi-squared analysis with p -value of ≤ 0.05 was used to test the significant association of different sequences.

Results  Water only images had highest mean CNR (296.35 ± 208.28) for the detection of bone marrow edema/osteitis. T1W (186.09 ± 96.96) and opposed-phase (OP) images (279.22 ± 188.40) had highest mean CNR for the detection of subchondral sclerosis and periarticular fat deposition, respectively. OP images ( p -value <0.001) followed by fat-only (FO) images ( p -value = 0.001) were superior to T1W sequences in detecting periarticular fat deposition. In-phase (IP) images in detecting subchondral sclerosis and IP and FO images in detecting cortical erosions were comparable to conventional T1W sequences ( p -value < 0.001).

Conclusions  T2 Dixon sequences are superior or comparable to conventional MR sequences in detection of sacroiliitis, except ankylosis. Hence, Dixon can be used as a single sequence to replace the multiple sequences used in conventional imaging protocol of acute sacroiliac joints due to higher image quality. It can be used as an additional sequence in case of chronic sacroiliitis to increase the confidence and accuracy of diagnosis.

Diffusion weighted imaging in breast cancer - Can it be a noninvasive predictor of nuclear grade?

BACKGROUND

DWI and ADC values are noninvasive MRI techniques, which provide quantitative information about tumor heterogeneity.

AIM

To determine the minimum and mean ADC values in breast carcinoma and to correlate ADC values with various prognostic factors.

SETTINGS AND DESIGN

Prospective observational study.

MATERIALS AND METHODS

Fifty-five patients with biopsy-proven breast carcinoma were included in this study. MRI with DWI was performed with Siemens 3T Skyra scanner. ADC values were measured by placing regions of interest (ROIs) within the targeted lesions on ADC maps manually. The histopathological and immunohistochemical analysis of surgical specimen was done to determine the prognostic factors.

STATISTICAL ANALYSIS

Students T test and ANOVA were used to study the difference in ADC between two groups. Pearson correlation coefficient was used to quantify the correlation between ADC values and prognostic factors.

RESULTS

Lower grade (grade I) breast carcinoma had a significantly high ADC value as compared to higher grade carcinoma (grade II and III). For differentiating Grade I tumors from grade II and III, a minimum ADC cut-off value was 0.79 × 10-3 mm2/sec (83% sensitivity and 84% specificity) and a mean ADC cut-off value was 0.82 × 10-3 mm2/sec (83% sensitivity and 71% specificity) was derived. There was no significant correlation between ADC and other prognostic factors.

CONCLUSION

ADC values can be used to differentiate lower grade breast carcinoma (grade I) from higher grades (grade II and III). Minimum ADC values are more accurate in predicting the grade of the breast tumor than mean ADC value.