Role of diffusion-weighted MR imaging in chest wall masses

The role of MRI in comparison between benign and malignant chest wall masses in correlation with pathology

Background

Tumors that arise from the chest wall (including bone structures such as the sternum, clavicle, scapula, and ribs) or from adjacent soft tissues are less common than other parts of the body, and so the resulting unfamiliarity can make it difficult to limit the number of possible diagnoses. These tumors have a wide range of possibilities, including primary chest wall tumors arising from the bone or soft tissue, which are subdivided into malignant and benign tumors, and the secondary metastatic deposits. The aim of the study is to investigate the ability of MRI with diffusion sequence in differentiation between benign and malignant chest wall masses, which is subsequently reflected in the management of chest wall masses patients.

Main body

MRI has superior soft-tissue resolution and value for local assessment of primary tumors and accurate tissue characterization and plays a key role in preoperative staging to assess for multi-spatial and multi-compartment involvement. ADC values were obtained in 31 patients, and the mean ADC values of benign (13 patients) chest wall masses were 1.31 ± 0.50 × 10−3 mm2/s while the mean ADC values of the malignant (18 patients) chest wall masses were 0.98 ± 0.36 × 10−3 mm2/s. There was a statistically significant difference between the ADC values obtained from the malignant and benign chest wall masses (P < 0.001).

Conclusion

This study demonstrates that diffusion-weighted MR imaging is a growing imaging modality to predict the histopathological differentiation of malignant from benign chest wall masses.

Diagnosed chest lesion on diffusion-weighted magnetic resonance images using apparent diffusion coefficients

PURPOSE

A novel diagnostic method using the standard deviation (SD) value of apparent diffusion coefficient (ADC) by diffusion-weighted (DWI) magnetic resonance imaging (MRI) is applied for differential diagnosis of primary chest cancers, metastatic tumors and benign tumors.

MATERIALS AND METHODS

This retrospective study enrolled 27 patients (20 males, 7 female; age, 15-85; mean age, 68) who had thoracic mass lesions in the last three years and underwent an MRI chest examination at our institution. In total, 29 mass lesions were analyzed using SD of ADC and DWI. Lesions were divided into five groups: Primary lung cancers (N = 10); esophageal cancers (N = 5); metastatic tumors (N = 8); benign tumors (N = 3); and inflammatory lesions (N = 3). Quantitative assessment of MRI parameters of mass lesions was performed. The ADC value was acquired based on the average of the entire tumor area. The error-plot, t-test and the area under receiver operating characteristic (AUC) were applied for statistical analysis.

RESULTS

The SD of ADC value (mean±SD) was (4.867±1.359)×10-4 mm2/sec in primary lung cancers, and (3.598±0.350)×10-4 mm2/sec in metastatic tumors. The SD of ADC values of primary lung cancers and metastatic tumors (P <  0.05) were significantly different and the AUC was 0.800 (P <  0.05). The means of SD of ADC values was 4.532±1.406×10-4 mm2/sec and 2.973±0.364×10-4 mm2/sec for malignant tumors (including primary lung cancers, esophageal cancers) and benign tumors with respectively. The mean of SD of ADC values between malignant chest tumors and benign chest tumors was shown significant difference (P <  0.01). The values of AUC was 0.967 between malignant chest tumors and benign chest tumors (P <  0.05). The ADC values for primary lung cancers, metastatic tumors and benign tumors were not significantly difference (P >  0.05).

CONCLUSIONS

The mean of SD of ADC value by DWI can be used for differential diagnosis of chest lesions.

Usefulness of diffusion-weighted magnetic resonance imaging-guided biopsy: pyothorax-associated lymphoma

The relatively rare entity pyothorax-associated lymphoma (PAL) is an aggressive disease with a poor prognosis. Therefore, PAL should be diagnosed as soon as possible with minimal invasion. We herein report the case of an 81-year-old man with PAL that was successfully treated with chemotherapy. A computed tomography-guided tumor biopsy could not provide adequate specimens for pathological investigation, whereas a diffusion-weighted magnetic resonance imaging-guided tumor biopsy led to a diagnosis. Our findings suggest that diffusion-weighted image guidance for planning the biopsy of an intrathoracic mass, especially in cases of suspected PAL, is a highly accurate method because it provides information about cellularity and does not create calcification-related artifacts.

Ovarian masses: is multi-detector computed tomography a reliable imaging modality?

BACKGROUND

Ovarian cancer continues to pose a major challenge to physicians and radiologists. It is the third most common gynecologic malignancy and estimated to be fifth leading cancer cause of death in women, constituting 23% of all gynecological malignancies. Multi-detector computed tomography (MDCT) appears to offer an excellent modality in diagnosing ovarian cancer based on combination of its availability, meticulous technique, efficacy and familiarity of radiologists and physicians. The aim of this study was to compute sensitivity, specificity, positive and negative predictive values and diagnostic accuracy of 64- slice MDCT in classifying ovarian masses; 95% confidence intervals were reported.

MATERIALS AND METHODS

We prospectively designed a cross-sectional analytical study to collect data from July 2010 to August 2011 from a tertiary care hospital in Karachi, Pakistan. A sample of 105 women aged between 15-80 years referred for 64-MDCT of abdomen and pelvis with clinical suspicion of malignant ovarian cancer, irrespective of stage of disease, were enrolled by non- probability purposive sampling. All patients who were already known cases of histologically proven ovarian carcinoma and having some contraindication to radiation or iodinated contrast media were excluded.

RESULTS

Our prospective study reports sensitivity, specificity; positive and negative predictive values with 95%CI and accuracy were computed. Kappa was calculated to report agreement among the two radiologists. For reader A, MDCT was found to have 92% (0.83, 0.97) sensitivity and 86.7% (0.68, 0.96) specificity, while PPV and NPV were 94.5% (0.86, 0.98) and 86.7% (0.63, 0.92), respectively. Accuracy reported by reader A was 90.5%. For reader B, sensitivity, specificity, PPV and NPV were 94.6% (0.86, 0.98) 90% (0.72, 0.97) 96% (0.88, 0.99) and 87.1% (0.69, 0.95) respectively. Accuracy computed by reader B was 93.3%. Excellent agreement was found between the two radiologists with a significant kappa value of 0.887.

CONCLUSION

Based on our study results, we conclude MDCT is a reliable imaging modality in diagnosis of ovarian masses accurately with insignificant interobserver variability.