Evidence map›Paper›PMID 42166098›Full record

ArticleInsights into imaging2026

Percentage signal recovery plus relative cerebral blood volume: a practical dual-parameter strategy for differentiating post-stereotactic radiosurgery tumour progression from radiation necrosis in brain metastases.

Vijay Sawlani, Nan Mei, Robert Flintham, Sara Meade, Helen Benghiat, Santhosh Nagaraju, Ismail Ughratdar, Nigel Davies, Ute Pohl, Paul Sanghera and 1 more

Abstract read
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Article in Insights into imaging, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.

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1 · What the graph read from it

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2 · The registry

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3 · Its place in the literature

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4 · The record

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5 · Who and what money

Authors and funding

11 authors.

Vijay Sawlani *University of Birmingham, Birmingham, UK. v.sawlani@bham.ac.uk.ORCID http://orcid.org/0000-0001-6779-1255
Nan Mei *Department of Imaging, Queen Elizabeth Hospital, University Hospitals Birmingham NHS FT, Birmingham, UK.
Robert FlinthamMedical Physics, Queen Elizabeth Hospital, University Hospitals Birmingham NHS FT, Birmingham, UK.
Sara MeadeOncology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS FT, Birmingham, UK.
Helen BenghiatOncology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS FT, Birmingham, UK.
Santhosh NagarajuPathology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS FT, Birmingham, UK.
Ismail UghratdarNeurosurgery, Queen Elizabeth Hospital, University Hospitals Birmingham NHS FT, Birmingham, UK.
Nigel DaviesMedical Physics, Queen Elizabeth Hospital, University Hospitals Birmingham NHS FT, Birmingham, UK.
Ute PohlPathology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS FT, Birmingham, UK.
Paul SangheraOncology, Queen Elizabeth Hospital, University Hospitals Birmingham NHS FT, Birmingham, UK.
Victoria WykesUniversity of Birmingham, Birmingham, UK.

Funding

No grant is acknowledged in the PubMed record.

6 · The paper itself

Abstract

objectivesStereotactic radiosurgery (SRS) is widely used for brain metastases, but differentiating tumour progression from radiation necrosis on conventional MRI remains difficult. Percentage signal recovery (PSR), derived from dynamic susceptibility contrast (DSC) perfusion MRI, reflects signal recovery post-contrast and offers insights into capillary permeability. This study aimed to evaluate PSR and relative cerebral blood volume (rCBV) and assess their combined diagnostic value in post-SRS brain metastases. MATERIALS AND

methodsPatients with enlarging post-SRS brain metastases and diagnostic uncertainty were retrospectively included. PSR and rCBV were extracted from DSC-MRI and normalised to contralateral white matter. The dataset was split into training and validation cohorts using stratified sampling. Logistic regression with 5-fold cross-validation and bootstrap validation was used. Diagnostic performance was assessed by ROC analysis.

resultsSixty-one patients (62 lesions; 26 progression, 36 necrosis) were included. Inter-rater reliability was excellent (ICC > 0.90). Progression showed higher rCBV (2.84 vs. 0.76) and lower PSR (95% vs. 176%) (both p < 0.001). Both were significant in univariate analysis; PSR remained independently predictive (p = 0.04) in multivariate analysis. PSR outperformed rCBV and the combined model in ROC analysis (validation AUCs: 0.960, 0.898, and 0.945, respectively), while the combined PSR and rCBV model maintained excellent sensitivity, specificity, and overall accuracy. Bootstrap-derived thresholds were 108% (PSR) and 1.96 (rCBV). A nomogram was developed for individualised risk estimation.

conclusionsPSR and rCBV provide complementary diagnostic information for post-SRS lesion assessment. PSR may offer additional value without requiring extra image acquisition, and integration of both parameters could enhance diagnostic confidence. Routine inclusion of PSR and rCBV in post-SRS imaging protocols could be recommended. CRITICAL RELEVANCE STATEMENT: This study demonstrates that combining DSC MRI-derived rCBV and PSR improves accuracy and efficiency in distinguishing tumour recurrence from radiation necrosis, offering a practical dual-parameter approach to enhance diagnosis and guide timely clinical decision-making in neurooncology. KEY POINTS: DSC MRI-derived rCBV and PSR may aid in improving diagnostic accuracy and reducing time-to-diagnosis in post-SRS brain metastases. PSR can be derived from the same DSC acquisition without additional scanning or correction and represents a practical parameter for post-SRS lesion assessment. Combining rCBV and PSR may improve diagnostic confidence, especially in equivocal cases, supporting routine use of this dual-parameter model.

Indexed as

Brain metastasesDynamic susceptibility contrastMagnetic resonance imagingRadiation necrosisTumour progression

Identifiers

PMID42166098
PMCPMC13194838

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.