Early Contrast Enhancement: A novel magnetic resonance imaging biomarker of pleural malignancy

Selina Tsim,Catherine A Humphreys,Gordon W Cowell,David B Stobo,Colin Noble,Rosemary Woodward,Caroline A Kelly,Laura Alexander,John E Foster,Craig Dick,Kevin G Blyth

doi:10.1016/j.lungcan.2018.01.014

Abstract

IntroductionPleural Malignancy (PM) is often occult on subjective radiological assessment. We sought to define a novel, semi-objective Magnetic Resonance Imaging (MRI) biomarker of PM, targeted to increased tumour microvessel density (MVD) and applicable to minimal pleural thickening. Materials and methods60 consecutive patients with suspected PM underwent contrast-enhanced 3-T MRI then pleural biopsy. In 58/60, parietal pleura signal intensity (SI) was measured in multiple regions of interest (ROI) at multiple time-points, generating ROI SI/time curves and Mean SI gradient (MSIG: SI increment/time). The diagnostic performance of Early Contrast Enhancement (ECE; which was defined as a SI peak in at least one ROI at or before 4.5 min) was compared with subjective MRI and Computed Tomography (CT) morphology results. MSIG was correlated against tumour MVD (based on Factor VIII immunostain) in 31 patients with Mesothelioma. Results71% (41/58) patients had PM. Pleural thickening was <10 mm in 49/58 (84%). ECE sensitivity was 83% (95% CI 61–94%), specificity 83% (95% CI 68–91%), positive predictive value 68% (95% CI 47–84%), negative predictive value 92% (78–97%). ECE performance was similar or superior to subjective CT and MRI. MSIG correlated with MVD (r = 0.4258, p = .02). DiscussionECE is a semi-objective, perfusion-based biomarker of PM, measurable in minimal pleural thickening. Further studies are warranted.

Highlights

Pleural Malignancy (PM) is often occult on subjective radiological assessment
Benign pleural diagnoses included BAPE (50%, n = 11), tuberculous pleurisy (14%, n = 3), fibrothorax (9%, n = 2), rheumatoid pleurisy (9%, n = 2), reactive effusion associated with lung cancer (4.5%, n = 1), post-lobectomy effusion (4.5%, n = 1), secondary to pulmonary thromboembolism (4.5%, n = 1) and drug-related (4.5%, n = 1)
We have described the acquisition and preliminary diagnostic performance of a novel, semi-objective Magnetic Resonance Imaging (MRI) biomarker of PM

Summary

Introduction

Pleural Malignancy (PM) is often occult on subjective radiological assessment. We sought to define a novel, semi-objective Magnetic Resonance Imaging (MRI) biomarker of PM, targeted to increased tumour microvessel density (MVD) and applicable to minimal pleural thickening. The diagnostic performance of Early Contrast Enhancement (ECE; which was defined as a SI peak in at least one ROI at or before 4.5 min) was compared with subjective MRI and Computed Tomography (CT) morphology results. Discussion: ECE is a semi-objective, perfusion-based biomarker of PM, measurable in minimal pleural thickening. Radiological detection of pleural malignancy (PM) is frequently difficult because overt pleural tumour may be occult and pleural effusion may be the dominant, or only, feature [1] This is true in early stage Malignant Pleural Mesothelioma (MPM), where extrapleural malignant features are frequently absent. Recent studies reflect these challenges, reporting low sensitivity and considerable inter-observer variation, using Computed Tomography (CT) in a routine clinical setting [2,3]. A major advantage of perfusion CT is its widespread availability, the multiplicity of protocols using different mathematical models [8] and high radiation burden have limited its widespread use in routine clinical practice to date [9,10]

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