DOI: 10.1148/radiol.2411051835
(Radiology 2006;241:319-320.)
© RSNA, 2006
Gadopentetate Dimeglumine and FDG Uptake in Liver Metastases
Kenneth Miles, FRCR,* and
Carolyn Keith, FRCR
* Division of Clinical & Laboratory Science, Brighton & Sussex Medical School, Falmer, Brighton BN1 9PX, United Kingdom
e-mail: k.a.miles{at}bsms.ac.uk
Department of Radiology, Royal North Shore Hospital, St Leonards, NSW, Australia
Editor:
The recent article by Dr van Laarhoven and colleagues (1) in the October 2005 issue of Radiology makes a valuable contribution to the available imaging data concerning the relationship between tumor vascularity and glucose metabolism. Such data are accumulating through combining positron emission tomography (PET) not only with magnetic resonance (MR) imaging but also with other techniques, such as perfusion computed tomography (CT).
The method adopted by Dr van Laarhoven and colleagues to quantify fluorine 18 fluorodeoxyglucose (FDG) uptake within hepatic metastases by using tumor-to-nontumor ratios is predicated on an assumption that FDG uptake in the apparently normal liver tissue adjacent to liver lesions is unaffected by the presence of tumor. However, this assumption may not be valid. Derangements of liver metabolism in patients with cancer are well recognized and include reduced hepatic glucose production and glucose recycling and altered glucose transport across hepatic cell membranes (2). In addition, we have previously observed in a series of 35 patients with colorectal cancer that hepatic FDG uptake in apparently healthy liver is significantly lower in patients with extrahepatic tumor than in patients without extrahepatic tumor (standardized uptake value: 1.88 vs 2.18, P < .05) (3).
Although they provide the TNM stage at the time of initial diagnosis, Dr van Laarhoven and colleagues do not report whole-body imaging findings at the time of restaging with PET. Thus, a high tumor-to-nontumor ratio for hepatic FDG uptake could simply reflect altered glucose metabolism within apparently normal liver in association with disseminated malignancy rather than increased FDG uptake in tumor tissue. If so, then the observed negative correlation between tumor-to-nontumor ratio of FDG uptake and gadopentetate dimeglumine uptake may indicate a greater propensity for dissemination among patients with hepatic metastases that exhibit lower vascularity. Indeed, results of pathologic and imaging studies suggest that, for hepatic metastases (as opposed to primary tumors), lower vascularity is associated with a poorer prognosis (4,5).
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References
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- van Laarhoven HW, de Geus-Oei LF, Wiering B, et al. Gadopentetate dimeglumine and FDG uptake in liver metastases of colorectal carcinoma as determined with MR imaging and PET. Radiology 2005;237:181–188.[Abstract/Free Full Text]
- Tayek JA. A review of cancer cachexia and abnormal glucose metabolism in humans with cancer. J Am Coll Nutr 1992;11:445–456.[Abstract]
- Miles KA, Comber L, Keith CJ, et al. Combining perfusion CT and FDG-PET data demonstrates reduced hepatic phosphorylation of glucose in patients with advanced colorectal cancer and poor survival [abstract]. Eur Radiol 2003;13(suppl 1):293.
- Mooteri S, Rubin D, Leurgans S, et al. Tumor angiogenesis in primary and metastatic colorectal cancers. Dis Colon Rectum 1996;39:1073–1080.[CrossRef][Medline]
- Miles KA, Leggett DA, Kelley BB, et al. In-vivo assessment of neovascularisation of liver metastases using perfusion CT. Br J Radiol 1998;71:276–281.[Abstract]
Response
Hanneke W. M. van Laarhoven, MA, MD, PhD,*,
Lioe-Fee de Geus-Oei, MD,
,
Bastiaan Wiering, MD,
,
Jasper Lok, BSc,
,
Mark Rijpkema, PhD,||,
Johannes H. A. M. Kaanders, MD, PhD,,
Paul F. M. Krabbe, PhD,#,
Theo Ruers, MD, PhD,,
Cornelis J. A. Punt, MD, PhD,*,
Albert J. van der Kogel, PhD,,
Wim J. G. Oyen, MD, PhD, and
Arend Heerschap, PhD||
* Departments of Medical Oncology, Nuclear Medicine, Surgery, Radiation Oncology, ||Radiology, #and Medical Technology Assessment, University Medical Center Nijmegen, Geert Grooteplein 8, 6500 HB Nijmegen, the Netherlands
e-mail: h.vanlaarhoven{at}onco.umcn.nl
We thank Drs Miles and Keith for their interesting suggestion that the observed negative correlation between tumor-to-nontumor ratio of FDG uptake and gadopentetate dimeglumine uptake (1) may indicate a greater propensity for dissemination among patients with hepatic metastases that exhibit lower vascularity. Their suggestion is based on the observation that glucose metabolism in patients with cancer may be altered (2) and hepatic FDG uptake in apparently healthy liver is significantly lower in patients with extrahepatic tumor (3). With respect to altered glucose metabolism, we would like to observe that our study population consisted of patients who underwent work-up for liver metastasectomy and who were all in relatively good condition (ie, no signs of cachexia). In all patients, the blood glucose levels at the start of the PET examination were known. The mean glucose level was 5.4 mmol/L (standard deviation, 1.1 mmol/L), which does not suggest the presence of altered glucose metabolism in these patients. There was no correlation between tumor-to-nontumor values and pre-PET glucose levels. With respect to the presence of extrahepatic disease, it should be noted that the preoperative screening of these patients with CT of the thorax and abdomen showed no evidence of extrahepatic disease, except in one patient (patient 12; this patient had two pulmonary metastases 
2 cm). The tumor-to-nontumor ratio of FDG uptake of this patient (ratio, 2.69) was well within the range of observed tumor-to-nontumor ratios (mean, 2.02; standard deviation, 0.82). During surgery, no extrahepatic intraabdominal metastases were found, except in one patient (patient 8) who had intraperitoneal metastases. However, this patient did not undergo PET and, therefore, did not contribute to the observed tumor-to-nontumor values. Thus, it is highly unlikely that in our study population the observed negative correlation between tumor-to-nontumor ratio of FDG uptake and gadopentetate dimeglumine uptake is caused by alterations in hepatic glucose metabolism rather than by increased glucose uptake in liver metastases.
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References
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- van Laarhoven HW, de Geus-Oei LF, Wiering B, et al. Gadopentetate dimeglumine and FDG uptake in liver metastases of colorectal carcinoma as determined with MR imaging and PET. Radiology 2005;237:181–188.[Abstract/Free Full Text]
- Tayek JA. A review of cancer cachexia and abnormal glucose metabolism in humans with cancer. J Am Coll Nutr 1992;11:445–456.[Abstract]
- Miles KA, Comber L, Keith CJ, et al. Combining perfusion CT and FDG-PET data demonstrates reduced hepatic phosphorylation of glucose in patients with advanced colorectal cancer and poor survival. Eur Radiol 2003;13(suppl 1):293.
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