Intracerebral metastasis showing restricted diffusion: correlation with histopathologic findings
G Duygulu1, G Yilmaz Ovali, C Calli
1Radiology Department, Ege University Medicine School, Izmir, Turkey.
Objective:
We aimed to detect the frequency of restricted diffusion in intracerebral metastases and to find whether there is correlation between the primary tumor pathology and diffusion-weighted MR imaging (DWI) findings of these metastases.
Material And Methods:
87 patients with intracerebral metastases were examined with routine MR imaging and DWI. 11 hemorrhagic metastatic lesions were excluded. The routine MR imaging included three plans before and after contrast enhancement. The DWI was performed with spin-echo EPI sequence with three b values (0, 500 and 1000), and ADC maps were calculated. 76 patients with metastases were grouped according to primary tumor histology and the ratios of restricted diffusion were calculated according to these groups. ADCmin values were measured within the solid components of the tumors and the ratio of metastases with restricted diffusion to that which do not show restricted diffusion were calculated. Fisher's exact and Mann-Whitney U tests were used for the statistical analysis.
Results:
Restricted diffusion was observed in a total of 15 metastatic lesions (19, 7%). Primary malignancy was lung carcinoma in 10 of these cases (66, 6%) (5 small cell carcinoma, 5 non-small cell carcinoma), and breast carcinoma in three cases (20%). Colon carcinoma and testicular teratocarcinoma were the other two primary tumors in which restricted diffusion in metastasis was detected. There was no statistical significant difference between the primary pathology groups which showed restricted diffusion (p>0.05). ADCmin values of solid components of the metastasis with restricted diffusion and other metastasis without restricted diffusion also showed no significant statistical difference (0.72+/-0.16x10(-3)mm(2)/s and 0.78+/-21x10(-3)mm(2)/s respectively) (p=0.325).
Conclusion:
Detection of restricted diffusion on DWI in intracerebral metastasis is not rare, particularly if the primary tumor is lung or breast cancer. However we found that there is no correlation between the metastasis showing restricted diffusion and primary pathology. Prospective studies with larger groups and more information are necessary regarding the correlation between the primary tumor histopathology and the ADC values of metastasis with restricted diffusion.
Insights
Restricted diffusion is frequently seen in brain metastases, especially from lung or breast cancer. However, this study found no direct link between restricted diffusion and the primary tumor
Area of Science:
- Neuroimaging
- Oncology
- Radiology
Background:
- Intracerebral metastases are secondary malignant tumors in the brain.
- Diffusion-weighted imaging (DWI) is a key MRI technique for evaluating tissue water diffusion.
- Restricted diffusion on DWI can indicate specific cellular characteristics of tumors.
Purpose of the Study:
- To determine the frequency of restricted diffusion in intracerebral metastases.
- To investigate the correlation between primary tumor pathology and DWI findings in brain metastases.
Main Methods:
- Retrospective analysis of 87 patients with intracerebral metastases.
- Routine MRI and DWI with b-values of 0, 500, and 1000 s/mm² were performed.
- ADC maps were calculated, and ADCmin values were measured in solid tumor components.
Main Results:
- Restricted diffusion was detected in 19.7% of metastatic lesions.
- Lung carcinoma (66.6%) and breast carcinoma (20%) were the most common primary tumors associated with restricted diffusion.
- No statistically significant correlation was found between primary tumor pathology and restricted diffusion (p>0.05).
Conclusions:
- Restricted diffusion in brain metastases is not uncommon, particularly with lung or breast primaries.
- The study did not find a correlation between restricted diffusion and primary tumor pathology.
- Further prospective studies with larger cohorts are needed to explore the histopathology-ADC value relationship.
