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The objective of our study was to evaluate the impact of body mass index (BMI) on dose, diagnostic performance, and image quality of a low-dose CT examination for renal colic.This retrospective study included all patients who underwent a low-dose CT examination for renal colic performed during the year 2012 with automatic tube current modulation, adaptive statistical iterative reconstruction, and a low tube voltage (kV). Three readers independently reviewed all images for the presence of renal colic and evaluated diagnostic confidence and image quality. The results and doses were compared among patients grouped by body mass index (BMI) and between patients with a BMI25 and those with a BMI≥25.Eighty-six patients were included in the study: 39 patients had a BMI25 and 47 had a BMI≥25. No statistically significant difference was found between the accuracy rates for the diagnosis of renal colic when the rates of the three independent readers were averaged for both BMI groups (95.7% vs 96.4%, respectively; p=0.83). Image quality and diagnostic confidence scores were significantly better for patients with a BMI≥25 than for patients with a BMI25 (mean image quality score, 3.7 vs 3.4, p0.001; mean diagnostic confidence score, 2.8 vs 2.5, p0.001). The mean radiation dose for patients with a BMI25 was 2.4 mGy compared with 3.7 mGy for patients with a BMI≥25 (p0.001).The diagnostic performance of our low-dose CT protocol for renal colic was excellent for all patients, and image quality and diagnostic confidence were significantly better for patients with a BMI≥25. However, our protocol also required exposure to a greater dose of radiation for these overweight and obese patients.

A glucose analogue labelled with iodine-123 in position 6 has been synthesized: [123I]-6-deoxy-6-iodo- d -glucose (6DIG). The aim of this study was to examine its biological behaviour in order to assess whether it could be used to evaluate glucose transport with SPECT. To establish whether 6DIG enters the cells using the glucose transporter, four biological models have been used: human erythrocytes in suspension, neonatal rat cardiomyocytes in culture, isolated perfused rat hearts, and biodistribution in mice. 6DIG competed with d -glucose to enter the cells and its entry was increased by insulin and inhibited in the presence of cytochalasin B. The biological behaviour of 6DIG was similar to that of 3-O-methyl- d -glucose. 6DIG is a tracer of glucose transport which is very promising for clinical studies.

6-deoxy-6-iodo-D-glucose (6-DIG) was rapidly taken up by adipocytes. Insulin increased 6-DIG transport in adipocytes isolated from both rats and mice. This stimulation was more important in rat than in mouse adipocytes, in agreement with their respective amount of Glut 4 transporters. In two insulin resistant states, the biological behavior of 6-DIG and 3-O-methyl-D-glucose was similar. These results indicated that 6-DIG, which was transported into the cells via the glucose transporters, could be potentially useful to measure modifications of glucose transport.

For an iodinated analogue of glucose to be useful for evaluating glucose uptake using single-photon emission computed tomography (SPECT), it must enter the cell via the same transporter as glucose and accumulate within the cell without being degraded. The biological behavior of the iodinated tracer must therefore be similar to that of 2-deoxy-d-[1- 14 C]-glucose (2-DG). In the present study, four experimental models (biodistribution in mouse, isolated rat heart, human erythrocytes in suspension and cultured neonatal rat cardiomyocytes) have been chosen and protocols have been set up which allow for the examination of small quantities of iodinated analogues of glucose. The uptakes of 2-DG and of l-[1- 14 C]-glucose have been measured in these models to establish reference values which will be compared with uptake values for iodinated analogues of glucose.