Application advances of habitat imaging based on CT or PET/CT: a systematic review

Habitat imaging (HI) enables the identification of tumor heterogeneity and characterization of the tumor microenvironment. Although HI based on MRI is well-established, its implementation using CT or PET/CT remains nascent and underexplored.

This systematic review analyzes recent advances in HI based on CT or PET/CT for tumor diagnosis and treatment, evaluating its clinical utility and limitations.

Literatures were systematically searched in PubMed, Embase, Web of Science, and Cochrane Library. Study quality was assessed using the radiomics quality score (RQS).

A total of 21 studies comprising 7363 patients were included. The number of radiomic features extracted ranged from 41 to 12,838 across studies. Cancer types included lung (47.6%), head and neck (14.3%), renal (14.3%), gastrointestinal (9.5%), ovarian (9.5%), and liver (4.8%). All included studies were retrospective in design. The mean RQS was 15.71 ± 3.06. Common limitations included the absence of scanner simulation studies, prospective validation, cost-effectiveness analyses, and data/code sharing. Furthermore, substantial heterogeneity was observed across studies in terms of image acquisition, segmentation methods, and habitat definitions.

HI based on CT or PET/CT demonstrates preliminary potential in evaluating treatment response, predicting prognosis, and revealing tumor pathological and molecular characteristics. However, the current evidence is of low-to-moderate quality with a risk of bias, and considerable methodological heterogeneity exists. The overall body of evidence remains at a relatively early stage. Prospective studies are needed to validate HI as a clinical biomarker.