MR-spectroscopy at 1.5 tesla and 3 tesla. Useful? A systematic review and meta-analysis. Eur J Radiol. 2012;81 Suppl 1:S6-S9. [PMID: 23083604 DOI: 10.1016/s0720-048x(12)70003-7]

Targeting choline phospholipid metabolism: GDPD5 and GDPD6 silencing decrease breast cancer cell proliferation, migration, and invasion

Abnormal choline phospholipid metabolism is associated with oncogenesis and tumor progression. We have investigated the effects of targeting choline phospholipid metabolism by silencing two glycerophosphodiesterase genes, GDPD5 and GDPD6, using small interfering RNA (siRNA) in two breast cancer cell lines, MCF-7 and MDA-MB-231. Treatment with GDPD5 and GDPD6 siRNA resulted in significant increases in glycerophosphocholine (GPC) levels, and no change in the levels of phosphocholine or free choline, which further supports their role as GPC-specific regulators in breast cancer. The GPC levels were increased more than twofold during GDPD6 silencing, and marginally increased during GDPD5 silencing. DNA laddering was negative in both cell lines treated with GDPD5 and GDPD6 siRNA, indicating absence of apoptosis. Treatment with GDPD5 siRNA caused a decrease in cell viability in MCF-7 cells, while GDPD6 siRNA treatment had no effect on cell viability in either cell line. Decreased cell migration and invasion were observed in MDA-MB-231 cells treated with GDPD5 or GDPD6 siRNA, where a more pronounced reduction in cell migration and invasion was observed under GDPD5 siRNA treatment as compared with GDPD6 siRNA treatment. In conclusion, GDPD6 silencing increased the GPC levels in breast cancer cells more profoundly than GDPD5 silencing, while the effects of GDPD5 silencing on cell viability/proliferation, migration, and invasion were more severe than those of GDPD6 silencing. Our results suggest that silencing GDPD5 and GDPD6 alone or in combination may have potential as a new molecular targeting strategy for breast cancer treatment. Copyright © 2016 John Wiley & Sons, Ltd.

Differential diagnosis of pancreatic cancer by single-shot echo-planar imaging diffusion-weighted imaging

AIM: To investigate the diagnostic ability of single-shot echo-planar imaging (EPI) diffusion-weighted imaging (DWI) to differentiate between malignant and benign pancreatic lesions.

METHODS: A computerized search was performed on PubMed, MEDLINE and EMBASE up to August 2014. Nine studies (10 sets of data) with a total of 304 malignant pancreatic lesions and 188 benign pancreatic lesions were included. The characteristics of each study included the study name, year of publication, magnetic resonance modalities used, patient population, strength of field, pulse time, repetition time, echo time (TE), maximum b factor, mean age, mean body weight, fat suppression, number of benign and malignant lesions, and true positive, true negative, false positive and false negative results. All analyses were performed using Meta-DiSc and Stata 11.0.

RESULTS: The pooled sensitivity and specificity of single-shot EPI DWI were 0.83 (95%CI: 0.79-0.87) and 0.77 (95%CI: 0.70-0.83), respectively. The positive likelihood ratio and negative likelihood ratio were 5.09 (95%CI: 2.19-11.84) and 0.23 (95%CI: 0.15-0.36), respectively. The P value for the χ² heterogeneity for all pooled estimates was < 0.05. From the fitted summary receiver operating characteristic curve, the area under the curve and Q* index were 0.89 and 0.82, respectively. Publication bias was not present (t = 0.58, P = 0.58). Meta-regression analysis indicated that fat suppression, mean age, TE, and maximum b factor were not sources of heterogeneity (all P > 0.05).

CONCLUSION: Single-shot EPI DWI is useful to differentiate between malignant and benign pancreatic lesions. Lesion size ≥ 2 cm is the limit for the diagnosis of early lesions.

1H-MRS evaluation of breast lesions by using total choline signal-to-noise ratio as an indicator of malignancy: a meta-analysis

The aim of this study was to evaluate the diagnostic performance of the use of total choline signal-to-noise ratio (tCho SNR) criteria in MRS studies for benign/malignant discrimination of focal breast lesions. We conducted (1) a meta-analysis based on 10 studies including 480 malignant breast lesions and 312 benign breast lesions and (2) a subgroup meta-analysis of tCho SNR ≥ 2 as cutoff for malignancy based on 7 studies including 371 malignant breast lesions and 239 benign breast lesions. (1) The pooled sensitivity and specificity of proton MRS with tCho SNR were 0.74 (95 % CI 0.69-0.77) and 0.76 (95 % CI 0.71-0.81), respectively. The PLR and NLR were 3.67 (95 % CI 2.30-5.83) and 0.25 (95 % CI 0.14-0.42), respectively. From the fitted SROC, the AUC and Q* index were 0.89 and 0.82. Publication bias was present (t = 2.46, P = 0.039). (2) Meta-regression analysis suggested that neither threshold effect nor evaluated covariates including strength of field, pulse sequence, TR and TE were sources of heterogeneity (all P value >0.05). (3) Subgroup meta-analysis: The pooled sensitivity and specificity were 0.79 and 0.72, respectively. The PLR and NLR were 3.49 and 0.20, respectively. The AUC and Q* index were 0.92 and 0.85. The use of tCho SNR criteria in MRS studies was helpful for differentiation between malignant and benign breast lesions. However, pooled diagnostic measures might be overestimated due to publication bias. A tCho SNR ≥ 2 as cutoff for malignancy resulted in higher diagnostic accuracy.

Differential diagnosis between malignant and benign breast lesions using single-voxel proton MRS: a meta-analysis

OBJECTIVES

We aim to investigate the diagnostic capability of single-voxel proton MR spectroscopy (MRS) for benign/malignant discrimination of focal breast lesions with a meta-analysis.

MATERIALS AND METHODS

The meta-analysis included a total of 750 malignant breast lesions and 419 benign breast lesions from eighteen studies.

RESULTS

The pooled sensitivity and specificity of MRS were 0.71 (95 % CI 0.68-0.74) and 0.85 (95 % CI 0.81-0.88), respectively. The positive likelihood ratio and negative LR were 4.11 (95 % CI 3.11-5.43) and 0.25 (95 % CI 0.17-0.36), respectively. The P value for χ(2) heterogeneity for all pooled estimates was <0.05. From the fitted summary receiver operating characteristics curve, AUC was 0.89 and Q* was 0.84. Asymmetrical in funnel plots indicated there may be publication bias (t = 2.85, P = 0.012). The meta-regression analysis indicated that neither threshold effect nor evaluated covariates that include strength of field, scanning technique (PRESS or STEAM), repetition time, NSA, and pre- or post-contrast agent were the sources of heterogeneity (all P value >0.05).

CONCLUSIONS

Single-voxel proton MRS was useful for differentiation between malignant and benign breast lesions. However, pooled diagnostic measures might be overestimated. The standardization of the acquisition protocol for MRS across the multicenter trials is recommended.