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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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Related in: MedlinePlus

Measurement of ADC metrics from brain metastases on diffusion-weighted MRI scans. A patient with a history of lung adenocarcinoma presents with headache and focal neurological deficit. A. Postcontrast T1-weighted sequence demonstrates a right frontal lesion, which was confirmed as a metastasis after excision. B. An ADC map is generated from B = 0.1000 images using post processing software. On this color map, blue areas represent low ADC and red higher ADC. C. A freehand region of interest is traced around the tumor border using the postcontrast T1-weighted sequence as reference on the axial slice with the largest tumor area and those immediately above and below. The ADCmin is the lowest bin of a histogram of ADC values for all pixels contained within this ROI, averaged over these three slices. Three ROI are placed within the tumor on the axial slice with the largest area, avoiding necrosis, haemorrhage, cyst and the mean taken to give ADCmean. D. To assess change of ADC across the tumor border, four ROI are placed starting just inside the tumor border and extending out into the peritumoral region. The slope of the four ADC values is taken as the “ADC transition coefficient” or ATC. This is repeated in 3 orthogonal directions, avoiding structures such as ventricle or falx and then repeated on two slices above and below, with the ATC being the mean of the 9 readings.
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Figure 1: Measurement of ADC metrics from brain metastases on diffusion-weighted MRI scans. A patient with a history of lung adenocarcinoma presents with headache and focal neurological deficit. A. Postcontrast T1-weighted sequence demonstrates a right frontal lesion, which was confirmed as a metastasis after excision. B. An ADC map is generated from B = 0.1000 images using post processing software. On this color map, blue areas represent low ADC and red higher ADC. C. A freehand region of interest is traced around the tumor border using the postcontrast T1-weighted sequence as reference on the axial slice with the largest tumor area and those immediately above and below. The ADCmin is the lowest bin of a histogram of ADC values for all pixels contained within this ROI, averaged over these three slices. Three ROI are placed within the tumor on the axial slice with the largest area, avoiding necrosis, haemorrhage, cyst and the mean taken to give ADCmean. D. To assess change of ADC across the tumor border, four ROI are placed starting just inside the tumor border and extending out into the peritumoral region. The slope of the four ADC values is taken as the “ADC transition coefficient” or ATC. This is repeated in 3 orthogonal directions, avoiding structures such as ventricle or falx and then repeated on two slices above and below, with the ATC being the mean of the 9 readings.

Mentions: Conventional MRI measures were taken on this postcontrast T1-weighted sequence including the number of lesions, maximum diameter on axial slices and volume (using three orthogonal measurements of diameter). The largest, operated metastasis only was assessed for those with multiple lesions (note that in general the cases with more than one metastasis included a dominant lesion with only small additional lesions). A number of different assessments of diffusion were made for each metastasis from the DWI scan and resulting ADC map. Figure 1 demonstrates the position of regions of interest (ROI) for recording these different ADC metrics. We have previously reported excellent intra and inter-observer reliability taking the readings below on this software for 12 of the 76 patients described, with one observer a clinical research fellow in neurosurgery and the second a clinician of 10 years specialised training in neuroradiology[20].


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)

Measurement of ADC metrics from brain metastases on diffusion-weighted MRI scans. A patient with a history of lung adenocarcinoma presents with headache and focal neurological deficit. A. Postcontrast T1-weighted sequence demonstrates a right frontal lesion, which was confirmed as a metastasis after excision. B. An ADC map is generated from B = 0.1000 images using post processing software. On this color map, blue areas represent low ADC and red higher ADC. C. A freehand region of interest is traced around the tumor border using the postcontrast T1-weighted sequence as reference on the axial slice with the largest tumor area and those immediately above and below. The ADCmin is the lowest bin of a histogram of ADC values for all pixels contained within this ROI, averaged over these three slices. Three ROI are placed within the tumor on the axial slice with the largest area, avoiding necrosis, haemorrhage, cyst and the mean taken to give ADCmean. D. To assess change of ADC across the tumor border, four ROI are placed starting just inside the tumor border and extending out into the peritumoral region. The slope of the four ADC values is taken as the “ADC transition coefficient” or ATC. This is repeated in 3 orthogonal directions, avoiding structures such as ventricle or falx and then repeated on two slices above and below, with the ATC being the mean of the 9 readings.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 1: Measurement of ADC metrics from brain metastases on diffusion-weighted MRI scans. A patient with a history of lung adenocarcinoma presents with headache and focal neurological deficit. A. Postcontrast T1-weighted sequence demonstrates a right frontal lesion, which was confirmed as a metastasis after excision. B. An ADC map is generated from B = 0.1000 images using post processing software. On this color map, blue areas represent low ADC and red higher ADC. C. A freehand region of interest is traced around the tumor border using the postcontrast T1-weighted sequence as reference on the axial slice with the largest tumor area and those immediately above and below. The ADCmin is the lowest bin of a histogram of ADC values for all pixels contained within this ROI, averaged over these three slices. Three ROI are placed within the tumor on the axial slice with the largest area, avoiding necrosis, haemorrhage, cyst and the mean taken to give ADCmean. D. To assess change of ADC across the tumor border, four ROI are placed starting just inside the tumor border and extending out into the peritumoral region. The slope of the four ADC values is taken as the “ADC transition coefficient” or ATC. This is repeated in 3 orthogonal directions, avoiding structures such as ventricle or falx and then repeated on two slices above and below, with the ATC being the mean of the 9 readings.
Mentions: Conventional MRI measures were taken on this postcontrast T1-weighted sequence including the number of lesions, maximum diameter on axial slices and volume (using three orthogonal measurements of diameter). The largest, operated metastasis only was assessed for those with multiple lesions (note that in general the cases with more than one metastasis included a dominant lesion with only small additional lesions). A number of different assessments of diffusion were made for each metastasis from the DWI scan and resulting ADC map. Figure 1 demonstrates the position of regions of interest (ROI) for recording these different ADC metrics. We have previously reported excellent intra and inter-observer reliability taking the readings below on this software for 12 of the 76 patients described, with one observer a clinical research fellow in neurosurgery and the second a clinician of 10 years specialised training in neuroradiology[20].

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