Spectral photon-counting CT imaging of colorectal peritoneal metastases: initial experience in rats

Abstract

computed tomography imaging plays a major role in the preoperative assessment of tumor burden by providing an accurate mapping of the distribution of peritoneal metastases (PM). Spectral Photon Counting Computed Tomography (SPCCT) is an innovative imaging modality that could overcome the current limitations of conventional CT, offering not only better spatial resolution but also better contrast resolution by allowing the discrimination of multiple contrast agents. Based on this capability, we tested the feasibility of SPCCT in the detection of PM at different time of tumor growth in 16 rats inoculated with CC531 cells using dual-contrast injection protocols in two compartments (i.e. intravenous iodine and intraperitoneal gadolinium or the reverse protocol), compared to surgery. For all peritoneal regions and for both protocols, sensitivity was 69%, specificity was 100% and accuracy was 80%, and the correlation with surgical exploration was strong (p = 0.97; p = 0.0001). No significant difference was found in terms of diagnostic performance, quality of peritoneal opacification or diagnostic quality between the 2 injection protocols. We also showed poor vascularization of peritoneal metastases by measuring low concentrations of contrast agent in the largest lesions using SPCCT, which was confirmed by immunohistochemical analyses. In conclusion, SPCCT using dualcontrast agent injection protocols in 2 compartments is a promising imaging modality to assess the extent of PM in a rat model. Peritoneal metastases (PM) are part of the natural history of most abdominal and gynecological malignancies and have long been considered as a terminal disease. Over the past decades, the development of cytoreductive surgery with or without intraoperative hyperthermal intraperitoneal chemotherapy (HIPEC) has led to an improvement in survival of selected patients with resectable disease 1-4. For colorectal cancer, this strategy has significantly improved oncology outcomes 4,5. The completeness of the cytoreductive surgery is a crucial endpoint and is directly associated with the extent and distribution of PM in the peritoneal cavity 6,7. However, this aggressive treatment is associated with substantial morbidity (30-40%) and a mortality rate that is reported to range from 0-10%, resulting in a further drastic selection of patients in the pre-treatment work-up 8,9. In this context, preoperative evaluation of the peritoneal tumor burden, although extremely challenging, is essential for the selection of eligible patients for curative treatment 10,11. Computed tomography (CT) remains the reference imaging modality to assess the extent of PM. Although magnetic resonance imaging (MRI) and positron emission tomography-CT (PET-CT) have good diagnostic performance in some PM etiologies, these modalities are mainly used as a complement to CT evaluation 10,12-17. However, even though CT imaging offers high spatial resolution and fast acquisition time, its main drawback is its lack of contrast resolution, leading to a significant underestimation ...

[Retracted] Correlation with Spectral CT Imaging Parameters and Occult Lymph Nodes Metastases in Sufferers with Isolated Lung Adenocarcinoma

“…Conventional CT examination has become the preferred imaging method for the diagnosis and differential diagnosis of lung cancer at this stage, but it mainly relies on the morphological changes of the lesions for diagnosis, resulting in high false-negative and false-positive rates in the diagnosis of lymph nodes metastasis. Spectral CT imaging technology is an excellent crystallization of the continuous optimization and development of imaging technology, which can improve more imaging information than conventional CT [ 12 – 14 ]. This study attempted to investigate the correlation with spectral CT imaging parameters and occult lymph nodes metastasis in sufferers with isolated lung adenocarcinoma, and the report is as follows.…”

A Prediction Model Intended for Exploratory Laparoscopy Risk Stratification in Colorectal Cancer Patients With Potential Occult Peritoneal Metastasis

“…Although some CT-based prediction models, including deep learning algorithms and spectral photon-counting imaging, have been established to diagnose PM, they still showed false-negative outcomes in small nodules and the proportion of false negatives increased with decreasing lesion size ( 21 , 28 ). Furthermore, the tedious steps of obtaining CT sequence images and importing them into algorithm would limit the clinical application of these models.…”

Cardiovascular and Thoracic Imaging: Trends, Perspectives and Prospects

“…Through its multi-energy CT capabilities, PCD technology enables a spectral tissue characterization and differentiation with or without the use of contrast agents, explaining the use of the term spectral photon-counting CT (SPCCT) in recent studies [1,[50][51][52][53][54][55][56][57][58][59][60][61][62][63][64][65][66]. Among these capabilities, K-edge imaging is one of the new features of SPCCT enabled by the energy-resolving characteristics of PCD.…”