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Diffusion-weighted MRI characteristics of the cerebral metastasis to brain boundary predicts patient outcomes.

Zakaria R, Das K, Radon M, Bhojak M, Rudland PR, Sluming V, Jenkinson MD - BMC Med Imaging (2014)

Bottom Line: Patient outcomes were overall survival and time to local recurrence.This was not simply due to differences between the types of primary cancer because the effect was observed even in a subgroup of 36 patients with the same primary, non-small cell lung cancer.The ATC was the only imaging measurement which independently predicted overall survival in multivariate analysis (hazard ratio 0.54, 95% CI 0.3 - 0.97, p = 0.04).

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neurosurgery, The Walton Centre NHS Foundation Trust, Liverpool, UK. rzakaria@nhs.net.

ABSTRACT

Background: Diffusion-weighted MRI (DWI) has been used in neurosurgical practice mainly to distinguish cerebral metastases from abscess and glioma. There is evidence from other solid organ cancers and metastases that DWI may be used as a biomarker of prognosis and treatment response. We therefore investigated DWI characteristics of cerebral metastases and their peritumoral region recorded pre-operatively and related these to patient outcomes.

Methods: Retrospective analysis of 76 cases operated upon at a single institution with DWI performed pre-operatively at 1.5T. Maps of apparent diffusion coefficient (ADC) were generated using standard protocols. Readings were taken from the tumor, peritumoral region and across the brain-tumor interface. Patient outcomes were overall survival and time to local recurrence.

Results: A minimum ADC greater than 919.4 × 10(-6) mm(2)/s within a metastasis predicted longer overall survival regardless of adjuvant therapies. This was not simply due to differences between the types of primary cancer because the effect was observed even in a subgroup of 36 patients with the same primary, non-small cell lung cancer. The change in diffusion across the tumor border and into peritumoral brain was measured by the "ADC transition coefficient" or ATC and this was more strongly predictive than ADC readings alone. Metastases with a sharp change in diffusion across their border (ATC >0.279) showed shorter overall survival compared to those with a more diffuse edge. The ATC was the only imaging measurement which independently predicted overall survival in multivariate analysis (hazard ratio 0.54, 95% CI 0.3 - 0.97, p = 0.04).

Conclusions: DWI demonstrates changes in the tumor, across the tumor edge and in the peritumoral region which may not be visible on conventional MRI and this may be useful in predicting patient outcomes for operated cerebral metastases.

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Changes in diffusion around a brain metastasis. A solitary metastasis in a patient with known renal cell carcinoma is shown in (A) with a clear boundary, necrotic centre and surrounding oedema, visible on the T2-weighted sequence. What is happening in the region around the metasasis? There is substantial evidence that this region consists of vasogenic oedema, higher diffusion and lower perfusion when compared to high grade glioma for example, but what about comparing within a group of metastases. (B). One can place serial regions of interest and measure and plot the ADC changes from the necrotic centre of the tumor through the leading edge and into the peritumoral regions. (C) Box and whisker plots showing the median, interquartile range and outliers for ADC readings in and around melanoma (n = 5) and non-small cell lung cancer (n = 36) metastases demonstrates differences in this ADC signature between the two groups and within them but the biological correlate of these differences needs to be investigated.
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Figure 6: Changes in diffusion around a brain metastasis. A solitary metastasis in a patient with known renal cell carcinoma is shown in (A) with a clear boundary, necrotic centre and surrounding oedema, visible on the T2-weighted sequence. What is happening in the region around the metasasis? There is substantial evidence that this region consists of vasogenic oedema, higher diffusion and lower perfusion when compared to high grade glioma for example, but what about comparing within a group of metastases. (B). One can place serial regions of interest and measure and plot the ADC changes from the necrotic centre of the tumor through the leading edge and into the peritumoral regions. (C) Box and whisker plots showing the median, interquartile range and outliers for ADC readings in and around melanoma (n = 5) and non-small cell lung cancer (n = 36) metastases demonstrates differences in this ADC signature between the two groups and within them but the biological correlate of these differences needs to be investigated.

Mentions: When visually inspecting the ADC maps for the 76 cases, however, it appeared that for a minority of metastases, in particular those from melanoma primaries, diffusion did vary greatly between the near and far peritumoral regions. The values of ADC at each point going out from the tumor towards normal white matter were plotted for illustrative purposes to show the “ADC signature” for that type of metastasis and an example of this is given in Figure 6. It was relevant to directly compare such patterns of ADC change in two types of cancer known to show differing mechanisms of brain invasion, as outlined in Discussion. The ratio of the near and far ADC values were therefore calculated for metastases of melanoma and non-small cell lung cancer and it was seen that for melanoma metastases this ratio was significantly higher (independent 2-tailed t test = 2.259, df 36, p = 0.03).


Diffusion-weighted MRI characteristics of the cerebral metastasis to brain boundary predicts patient outcomes.

Zakaria R, Das K, Radon M, Bhojak M, Rudland PR, Sluming V, Jenkinson MD - BMC Med Imaging (2014)

Changes in diffusion around a brain metastasis. A solitary metastasis in a patient with known renal cell carcinoma is shown in (A) with a clear boundary, necrotic centre and surrounding oedema, visible on the T2-weighted sequence. What is happening in the region around the metasasis? There is substantial evidence that this region consists of vasogenic oedema, higher diffusion and lower perfusion when compared to high grade glioma for example, but what about comparing within a group of metastases. (B). One can place serial regions of interest and measure and plot the ADC changes from the necrotic centre of the tumor through the leading edge and into the peritumoral regions. (C) Box and whisker plots showing the median, interquartile range and outliers for ADC readings in and around melanoma (n = 5) and non-small cell lung cancer (n = 36) metastases demonstrates differences in this ADC signature between the two groups and within them but the biological correlate of these differences needs to be investigated.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4126355&req=5

Figure 6: Changes in diffusion around a brain metastasis. A solitary metastasis in a patient with known renal cell carcinoma is shown in (A) with a clear boundary, necrotic centre and surrounding oedema, visible on the T2-weighted sequence. What is happening in the region around the metasasis? There is substantial evidence that this region consists of vasogenic oedema, higher diffusion and lower perfusion when compared to high grade glioma for example, but what about comparing within a group of metastases. (B). One can place serial regions of interest and measure and plot the ADC changes from the necrotic centre of the tumor through the leading edge and into the peritumoral regions. (C) Box and whisker plots showing the median, interquartile range and outliers for ADC readings in and around melanoma (n = 5) and non-small cell lung cancer (n = 36) metastases demonstrates differences in this ADC signature between the two groups and within them but the biological correlate of these differences needs to be investigated.
Mentions: When visually inspecting the ADC maps for the 76 cases, however, it appeared that for a minority of metastases, in particular those from melanoma primaries, diffusion did vary greatly between the near and far peritumoral regions. The values of ADC at each point going out from the tumor towards normal white matter were plotted for illustrative purposes to show the “ADC signature” for that type of metastasis and an example of this is given in Figure 6. It was relevant to directly compare such patterns of ADC change in two types of cancer known to show differing mechanisms of brain invasion, as outlined in Discussion. The ratio of the near and far ADC values were therefore calculated for metastases of melanoma and non-small cell lung cancer and it was seen that for melanoma metastases this ratio was significantly higher (independent 2-tailed t test = 2.259, df 36, p = 0.03).

Bottom Line: Patient outcomes were overall survival and time to local recurrence.This was not simply due to differences between the types of primary cancer because the effect was observed even in a subgroup of 36 patients with the same primary, non-small cell lung cancer.The ATC was the only imaging measurement which independently predicted overall survival in multivariate analysis (hazard ratio 0.54, 95% CI 0.3 - 0.97, p = 0.04).

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Neurosurgery, The Walton Centre NHS Foundation Trust, Liverpool, UK. rzakaria@nhs.net.

ABSTRACT

Background: Diffusion-weighted MRI (DWI) has been used in neurosurgical practice mainly to distinguish cerebral metastases from abscess and glioma. There is evidence from other solid organ cancers and metastases that DWI may be used as a biomarker of prognosis and treatment response. We therefore investigated DWI characteristics of cerebral metastases and their peritumoral region recorded pre-operatively and related these to patient outcomes.

Methods: Retrospective analysis of 76 cases operated upon at a single institution with DWI performed pre-operatively at 1.5T. Maps of apparent diffusion coefficient (ADC) were generated using standard protocols. Readings were taken from the tumor, peritumoral region and across the brain-tumor interface. Patient outcomes were overall survival and time to local recurrence.

Results: A minimum ADC greater than 919.4 × 10(-6) mm(2)/s within a metastasis predicted longer overall survival regardless of adjuvant therapies. This was not simply due to differences between the types of primary cancer because the effect was observed even in a subgroup of 36 patients with the same primary, non-small cell lung cancer. The change in diffusion across the tumor border and into peritumoral brain was measured by the "ADC transition coefficient" or ATC and this was more strongly predictive than ADC readings alone. Metastases with a sharp change in diffusion across their border (ATC >0.279) showed shorter overall survival compared to those with a more diffuse edge. The ATC was the only imaging measurement which independently predicted overall survival in multivariate analysis (hazard ratio 0.54, 95% CI 0.3 - 0.97, p = 0.04).

Conclusions: DWI demonstrates changes in the tumor, across the tumor edge and in the peritumoral region which may not be visible on conventional MRI and this may be useful in predicting patient outcomes for operated cerebral metastases.

Show MeSH
Related in: MedlinePlus