Detectability and structural stability of a liquid fiducial marker in fresh ex vivo pancreas tumour resection specimens on CT and 3T MRI.
Strahlenther Onkol
; 195(8): 756-763, 2019 Aug.
Article
em En
| MEDLINE
| ID: mdl-31143995
ABSTRACT
PURPOSE:
To test the detectability of a liquid fiducial marker injected into ex vivo pancreas tumour tissue on magnetic resonance imaging (MRI) and computed tomography (CT). Furthermore, its injection performance using different needle sizes and its structural stability after fixation in formaldehyde were investigated.METHODS:
Liquid fiducial markers with a volume of 20-100⯵l were injected into freshly resected pancreas specimens of three patients with suspected adenocarcinoma. Xray guided injection was performed using different needle sizes (18â¯G, 22â¯G, 25â¯G). The specimens were scanned on MRI and CT with clinical protocols. The markers were segmented on CT by signal thresholding. Marker detectability in MRI was assessed in the registered segmentations. Marker volume on CT was compared to the injected volume as a measure of backflow.RESULTS:
Markers with a volume ≥20⯵l were detected as hyperintensity on Xray and CT. On T1- and T2-weighted 3T MRI, marker sizes ranging from 20-100⯵l were visible as hypointensity. Since most markers were non-spherical, MRI detectability was poor and their differentiation from hypointensities caused by air cavities or surgical clips was only feasible with a reference CT. Marker backflow was only observed when using an 18-G needle. A volume decrease of 6.6⯱ 13.0% was observed after 24â¯h in formaldehyde and, with the exception of one instance, no wash-out occurred.CONCLUSIONS:
The liquid fiducial marker injected in ex vivo pancreatic resection specimen was visible as hyperintensity on kV Xray and CT and as hypointensity on MRI. The marker's size was stable in formaldehyde. A marker volume of ≥50⯵L is recommended in clinically used MRI sequences. In vivo injection is expected to improve the markers sphericity due to persisting metabolism and thereby enhance detectability on MRI.Palavras-chave
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Neoplasias Pancreáticas
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Imageamento por Ressonância Magnética
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Adenocarcinoma
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Tomografia Computadorizada por Raios X
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Pancreaticoduodenectomia
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Marcadores Fiduciais
Tipo de estudo:
Guideline
Limite:
Aged
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Female
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Humans
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Male
Idioma:
En
Revista:
Strahlenther Onkol
Ano de publicação:
2019
Tipo de documento:
Article