Kenneth A. Miles

Imaging colorectal cancer has become a major indication for positron emission tomography using fluorodeoxyglucose (FDG-PET). In primary diagnosis and staging, the role for this technique is limited but FDG-PET has proved highly accurate in the detection of recurrent tumour. The three main indications are (i) characterisation of a residual structural lesion after definitive therapy, (ii) pre-operative staging prior to resection of apparently isolated metastasis, and (iii) investigation of rising carcinoembryonic antigen (CEA) in a patient with normal structural imaging. The diagnostic accuracy of FDG-PET translates to changes in management in a large number of patients, resulting in improved cost-effectiveness. FDG-PET is fast becoming the standard of clinical care for patients with recurrent colorectal cancer.

Dynamic contrast-enhanced computed tomography (DCE-CT) assesses the vascular support of tumours through analysis of temporal changes in attenuation in blood vessels and tissues during a rapid series of images acquired with intravenous administration of iodinated contrast material. Commercial software for DCE-CT analysis allows pixel-by-pixel calculation of a range of validated physiological parameters and depiction as parametric maps. Clinical studies support the use of DCE-CT parameters as surrogates for physiological and molecular processes underlying tumour angiogenesis. DCE-CT has been used to provide biomarkers of drug action in early phase trials for the treatment of a range of cancers. DCE-CT can be appended to current imaging assessments of tumour response with the benefits of wide availability and low cost. This paper sets out guidelines for the use of DCE-CT in assessing tumour vascular support that were developed using a Delphi process. Recommendations encompass CT system requirements and quality assurance, radiation dosimetry, patient preparation, administration of contrast material, CT acquisition parameters, terminology and units, data processing and reporting. DCE-CT has reached technical maturity for use in therapeutic trials in oncology. The development of these consensus guidelines may promote broader application of DCE-CT for the evaluation of tumour vascularity. Key Points • DCE-CT can robustly assess tumour vascular support • DCE-CT has reached technical maturity for use in therapeutic trials in oncology • This paper presents consensus guidelines for using DCE-CT in assessing tumour vascularity

Can imaging help improve the survival of cancer patients? - Cancer Imaging Can imaging help improve the survival of cancer patients? - Survival, quality-adjusted survival and mortality are important and related measures of outcome in cancer care. The impact of imaging on these outcomes can be ascertained from observational and modelling studies, frequently performed to evaluate cost-effectiveness.

To assess the utility of texture analysis of liver computed tomographic (CT) images by determining the effect of acquisition parameters on texture and by comparing the abilities of texture analysis and hepatic perfusion CT to help predict survival for patients with colorectal cancer. The study comprised a phantom test and a clinical evaluation of 48 patients with colorectal cancer who had consented to retrospective analysis of hepatic perfusion CT data acquired during a research study approved by the institutional review board. Both components involved texture analysis to quantify the relative contribution of CT features between 2 and 12 pixels wide to overall image brightness and uniformity. The effect of acquisition factors on texture was assessed on CT images of a cylindric phantom filled with water obtained by using tube currents between 100 and 250 mAs and voltages between 80 and 140 kVp. Texture on apparently normal portal phase CT images of the liver and hepatic perfusion parameters were related to patient survival by using Kaplan-Meier survival analysis. A texture parameter that compared the uniformity of distribution of CT image features 10 and 12 pixels wide exhibited the least variability with CT acquisition parameters (maximum coefficient of variation, 2.6%) and was the best predictor of patient survival (P < .005). There was no significant association between survival and hepatic perfusion parameters. The study provides preliminary evidence that analysis of liver texture on portal phase CT images is potentially a superior predictor of survival for patients with colorectal cancer than CT perfusion imaging. http://radiology.rsnajnls.org/cgi/content/full/2502071879/DC1.

KEYNOTE LECTURE: PET-CT in oncology: making the most of CT - Cancer Imaging KEYNOTE LECTURE: PET-CT in oncology: making the most of CT - Combined positron emission tomography-computed tomography (PET-CT) has made a significant impact on cancer imaging. The use of CT to map tissue attenuation for correction of PET images and the ability to co-register the functional information provided by PET with the anatomical data afforded by CT, has resulted in demonstrable improvements in diagnostic accuracy. However, attenuation correction and anatomical localisation may not represent the full benefits of integrating CT with PET.

Warburg revisited: imaging tumour blood flow and metabolism - Cancer Imaging Warburg revisited: imaging tumour blood flow and metabolism - In the 1930s, Otto Warburg reported that anaerobic metabolism of glucose is a fundamental property of all tumours, even in the presence of an adequate oxygen supply. He also demonstrated a relationship between the degree of anaerobic metabolism and tumour growth rate. Today, this phenomenon forms the basis of tumour imaging with fluorodeoxyglucose positron emission tomography (FDG-PET).

Colorectal cancer: imaging surveillance following resection of primary tumour - Cancer Imaging Colorectal cancer: imaging surveillance following resection of primary tumour - Most patients with colorectal cancer undergo treatment with curative intent and subsequently enter a surveillance programme. The primary aim of surveillance is to identify patients with disease relapse at a resectable stage. However, the identification of local recurrence and metachronous carcinoma are also important aspects of follow up. Patients under observation may be referred for imaging either because regular imaging forms part of the surveillance strategy, or because tumour relapse is suggested by the development of new symptoms or a rise in tumour markers.

The availability of rapid imaging with multidetector CT systems and commercial analysis software has made perfusion imaging with CT an everyday technique, not only for the brain but also for other body organs. Perfusion imaging is usually performed as an adjunct to a conventional CT examination and is therefore particularly appropriate when a conventional CT is part of routine clinical protocols. The derived values are reproducible and have been validated against a range of reference techniques. Within neuroradiology, perfusion CT has attracted interest in the assessment of acute stroke but can also be used to assess secondary injury in head trauma and as an adjunct to CT angiography to evaluate cerebral spasm in subarachnoid haemorrhage. Within oncology, perfusion CT provides an imaging correlate for tumour vascularity that can be used to discriminate benign and malignant lesions, as an indicator of tumour aggressiveness, to reveal occult tumour and improve the delineation of tumours during radiotherapy planning, and as a functional assessment of tumour response to therapy. By exploiting the ability of CT systems to quantify contrast enhancement, CT perfusion imaging uses contrast media to assess vascular physiology and so improve diagnosis, prognosis, treatment selection and therapy monitoring.