PET-CT-guided interventions in the management of FDG-positive lesions in patients suffering from solid malignancies: initial experiences

Abstract

Positron emission tomography-computed tomography (PET-CT) has gained widespread acceptance as a staging investigation in the diagnostic workup of malignant tumours and may be used to visualize metabolic changes before the evolution of morphological changes. To make histology of PET findings without distinctive structural changes available for treatment decisions, we developed a protocol for multimodal image-guided interventions using an integrated PET-CT machine. We report our first experience in 12 patients admitted for staging and restaging of breast cancer, non-small cell lung cancer, cervical cancer, soft tissue sarcoma, and osteosarcoma. Patients were repositioned according to the findings in PET-CT and intervention was planned based on a subsequent single-bed PET-CT acquisition of the region concerned. The needle was introduced under CT guidance in a step-by-step technique and correct needle position in the centre of the FDG avid lesion was assured by repetition of a single-bed PET-CT acquisition before sampling. The metabolically active part of lesions was accurately targeted in all patients and representative samples were obtained in 92%. No major adverse effects occurred. We conclude that PET-CT guidance for interventions is feasible and may be promising to optimize the diagnostic yield of CTguided interventions and to make metabolically active lesions without morphological correlate accessible to percutaneous interventions.

Prognostic Stratification of Metastatic Gastroenteropancreatic Neuroendocrine Neoplasms by 18F-FDG PET: Feasibility of a Metabolic Grading System

“…This concept of relying on metabolic target lesions ( 18 F-FDG metabolic hot spots within the body) for prognostication resembles in a macroscopic way the principle of immunohistochemical grading (Ki-67 index estimation), in which only the proliferative hot spots within a tumor are chosen to determine the proliferative fraction. Including the most aggressive and probably prognostically relevant lesions in tumor heterogeneity or diverging tumor populations may become of increasing importance in later stages of metastatic disease (10), and thus, whole-body molecular imagingbased surveillance might constitute an advantage over proliferation assessment based on non-PET-guided biopsy (25)(26)(27). The value of 18 F-FDG PET in NENs seems of particular interest during the unresectable metastatic stage, as investigated in our study.…”

A navigation system for percutaneous needle interventions based on PET/CT images: Design, workflow and error analysis of soft tissue and bone punctures

“…The system workflow, like the standard nonnavigated PET/CT intervention [3], begins after diagnosis and continues until the target is reached. The process is divided into two phases: non-sterile and sterile.…”

“…By using combinations of structural and functional modalities (SPECT/CT and PET/CT), image understanding, and therefore diagnosis, can be optimized [1,2]. With these techniques, even suspicious lesions without morphological correlation, i.e., those not evident in structural datasets, can be identified and verified histologically [3]. In multimodal image interventions, the functional image (e.g., PET or SPECT) provides information about the target, while the structural image (e.g., CT, MRI, etc.)…”

“…Phantom experiments have demonstrated the feasibility of using such navigation systems with multimodal images. However, the handling of multiple acquisitions of structural images as well as different sets of metabolic images while following clinically approved protocols for oncologic needle interventions, such as in reference [3], still requires investigation. Additionally, most of the presented systems do not distinguish clearly between lesions located in bone and those in soft tissue.…”

Multimodal target correction by local bone registration: A PET/CT evaluation

“…With these techniques even suspicious lesions without morphological correlation, i.e. not evident in structural datasets, can be identified and verified histologically, following biopsy [3].…”