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Mol Imaging Biol. 2018 Dec;20(6):1044-1052. doi: 10.1007/s11307-018-1196-9.

Impact of Computer-Aided CT and PET Analysis on Non-invasive T Staging in Patients with Lung Cancer and Atelectasis.

Author information

1
Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120, Heidelberg, Germany. paul.flechsig@med.uni-heidelberg.de.
2
Translational Lung Research Center Heidelberg, Member of the German Center for Lung Research DZL, Heidelberg, Germany. paul.flechsig@med.uni-heidelberg.de.
3
Department of Nuclear Medicine, University Hospital Heidelberg, INF 400, 69120, Heidelberg, Germany.
4
Medical Faculty, Department of Diagnostic and Interventional Radiology, University Dusseldorf, 40225, Dusseldorf, Germany.
5
Department of Biostatistics, German Cancer Research Center, Heidelberg, Germany.
6
Institute of Pathology, University Hospital Heidelberg, Heidelberg, Germany.
7
Translational Lung Research Center Heidelberg, Member of the German Center for Lung Research DZL, Heidelberg, Germany.
8
Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg, Germany.
9
Clinical Cooperation Unit, Department of Nuclear Medicine, DKFZ, Heidelberg, Germany.
10
Department of Radiology, Columbia University Medical Centre, New York Presbyterian Hospital, New York, NY, USA.

Abstract

PURPOSE:

Tumor delineation within an atelectasis in lung cancer patients is not always accurate. When T staging is done by integrated 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG)-positron emission tomography (PET)/X-ray computer tomography (CT), tumors of neuroendocrine differentiation and slowly growing tumors can present with reduced FDG uptake, thus aggravating an exact T staging. In order to further exhaust information derived from [18F]FDG-PET/CT, we evaluated the impact of CT density and maximum standardized uptake value (SUVmax) for the classification of different tumor subtypes within a surrounding atelectasis, as well as possible cutoff values for the differentiation between the primary tumor and atelectatic lung tissue.

PROCEDURES:

Seventy-two patients with histologically proven lung cancer and adjacent atelectasis were investigated. Non-contrast-enhanced [18F]FDG-PET/CT was performed within 2 weeks before surgery/biopsy. Boundaries of the primary within the atelectasis were determined visually on the basis of [18F]FDG uptake; CT density was quantified manually within each primary and each atelectasis.

RESULTS:

CT density of the primary (36.4 Hounsfield units (HU) ± 6.2) was significantly higher compared to that of atelectatic lung (24.3 HU ± 8.3; p < 0.01), irrespective of the histological subtype. The discrimination between different malignant tumors using density analysis failed. SUVmax was increased in squamous cell carcinomas compared to adenocarcinomas. Irrespective of the malignant subtype, a possible cutoff value of 24 HU may help to exclude the presence of a primary in lesions below 24 HU, whereas a density above a threshold of 40 HU can help to exclude atelectatic lung.

CONCLUSION:

Density measurements in patients with lung cancer and surrounding atelectasis may help to delineate the primary tumor, irrespective of the specific lung cancer subtype. This could improve T staging and radiation treatment planning (RTP) without additional application of a contrast agent in CT, or an additional magnetic resonance imaging (MRI), even in cases of lung tumors of neuroendocrine differentiation or in slowly growing tumors with less avidity to [18F]FDG.

KEYWORDS:

Computed tomography; FDG-PET/CT; Lung cancer; Staging

PMID:
29679299
DOI:
10.1007/s11307-018-1196-9
[Indexed for MEDLINE]

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