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Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet]. York (UK): Centre for Reviews and Dissemination (UK); 1995-.

Database of Abstracts of Reviews of Effects (DARE): Quality-assessed Reviews [Internet].

Magnetic resonance (MR) differential diagnosis of breast tumors using apparent diffusion coefficient (ADC) on 1.5-T

Y Tsushima, A Takahashi-Taketomi, and K Endo.

Review published: 2009.

Link to full article: [Journal publisher]

CRD summary

This review evaluated the apparent diffusion coefficient (ADC) for identifying malignant and benign breast tumours. The authors concluded that ADC evaluation was useful for differentiating between malignant and benign tumours. In view of the limited search, lack of reporting of the review methods and study quality, and differences between studies, the authors' conclusions may not be reliable.

Authors' objectives

The authors evaluated the apparent diffusion coefficient (ADC) for identifying malignant and benign breast tumours.

Searching

MEDLINE was searched for peer-reviewed studies from January 2000 to December 2008. Search terms were reported and reference lists of identified studies were also searched.

Study selection

Eligible for inclusion in the review were studies of women, where: the data were obtained using a 1.5 tesla magnetic resonance unit; the magnetic resonance imaging sequence and diagnostic criteria for malignant and benign tumours were clearly stated; diffusion weighted images were obtained and ADC values were calculated; and ADC values of breast tumours were reported with their means and standard deviations.

Magnetic resonance units were manufactured by GE, Siemens, or Philips and, in the majority of studies, echo-planar imaging was used. Repetition time ranged from 2,000 to 6,238 milliseconds, where reported, and echo time ranged from 61.8 to 135 milliseconds. The maximum b factor ranged from 300 to 1,074 seconds per mm2 and the number of b factors ranged from two to five. The mean age of patients ranged from 50 to 58 years, where reported. The included studies examined the following: malignant and benign tumours; invasive and noninvasive ductal carcinoma; and normal tissue. Most of the tumours were histologically proven.

The authors did not state how the studies were selected for inclusion in the review.

Assessment of study quality

The authors did not state whether study quality was assessed.

Data extraction

Data were extracted to calculate the true positives, false positives, false negatives, and true negatives, sensitivity, specificity, and diagnostic odds ratios.

The authors did not state how many reviewers performed the data extraction.

Methods of synthesis

Only studies, in which the absolute numbers of true positives, false positives, false negatives, and true negatives were available or could be calculated, were included in the analysis. The pooled specificity and sensitivity and their associated 95% confidence intervals were calculated using a random-effects (DerSimonian and Laird) model. Statistical heterogeneity was assessed using the Cochran Q and the I2 tests. Substantial statistical heterogeneity was defined as an I2 value of over 50%.

A summary receiver operating characteristic (sROC) curve was produced. Meta-regression was used to explore the possible sources of heterogeneity, such as the magnetic resonance unit, scanning technique, repetition time, echo time, maximum b factor, number of b factors used for ADC calculation, mean size of tumour (mm), and mean age of patients. The correlation between sensitivity and specificity was assessed using the Spearman correlation coefficient.

Publication bias was assessed using a funnel plot.

Results of the review

Twelve studies (n=670 patients) were included in the review and six of these were included in the analysis (n=477 patients). The sample sizes of the six studies analysed ranged from 30 to 167 patients.

All studies showed lower ADC values for breast cancer compared with normal tissue or benign tumours. The pooled sensitivity was 89% (95% CI 85 to 91) and the pooled specificity was 77% (95% CI 69 to 84). There was evidence of substantial statistical heterogeneity (I2=68.4% for sensitivity and 70.0% for specificity). The pooled diagnostic odds ratio was 28.56 (95% CI 12.27 to 66.44), for which no I2 value was reported.

The sROC curve did not fit the data points indicating that variation among studies was due to differences other than in threshold values for cancer. There was no statistically significant inverse correlation between sensitivity and specificity indicating significant heterogeneity across the studies. None of the covariates used in the meta-regression was statistically significant, so the cause of the heterogeneity could not be identified.

The funnel plot showed asymmetry, indicating publication bias.

Authors' conclusions

Apparent diffusion coefficient evaluation was useful for differentiating between malignant and benign breast tumours.

CRD commentary

This review addressed a clear research question. The search strategy was limited to one database and excluded non-peer reviewed material. This means that relevant studies might have been missed and this appears to be the case given the evidence of publication bias from the funnel plot. The inclusion criteria were appropriate. The design of the included studies was not reported and no study quality assessment was reported. This means that the validity of the included studies is unclear. The number of reviewers involved in the processes of study selection and data extraction were not reported so it is unclear whether these two processes were subject to reviewer error or bias. The methods of statistical synthesis were appropriate.

In view of the limited search, lack of reporting on review methods and study quality, and differences between studies, the authors' conclusions may not be reliable.

Implications of the review for practice and research

Practice: The authors did not state any implications for practice.

Research: The authors stated that further studies were needed to investigate the usefulness of evaluating the ADC to differentiate between malignant and benign tumours, and to optimise the ADC parameters.

Funding

Not stated.

Bibliographic details

Tsushima Y, Takahashi-Taketomi A, Endo K. Magnetic resonance (MR) differential diagnosis of breast tumors using apparent diffusion coefficient (ADC) on 1.5-T Journal of Magnetic Resonance Imaging 2009; 30(2): 249-255. [PubMed: 19629992]

Indexing Status

Subject indexing assigned by NLM

MeSH

Breast Neoplasms /diagnosis /pathology; Data Interpretation, Statistical; Diagnosis, Differential; Diffusion Magnetic Resonance Imaging /methods; Female; Humans

AccessionNumber

12009108235

Database entry date

28/04/2010

Record Status

This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.

CRD has determined that this article meets the DARE scientific quality criteria for a systematic review.

Copyright © 2014 University of York.

PMID: 19629992

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