Multislice CT pops the cork noninvasively

It may be too soon for a television series called "CSI: Radiology," but multislice CT technology is finding uses beyond the realms of clinical or even forensic medicine. Swiss researchers have devised a way to detect smuggled dissolved cocaine using MSCT scanners (AJR:190, May 2008).

Smuggled dissolved drugs, particularly cocaine, in bottled solution are an ongoing problem for customs officials at international borders. Common fluoroscopy of packages currently in use at border checkpoints or ports of entry cannot detect liquids contaminated with contraband.

Smugglers dissolve the drug and hide it in a few bottles of, say, wine. They fill the remainder of the shipment with uncontaminated liquid, making detection less likely, since border checks are usually restricted to random sampling.

"Our screening method can test all bottles rapidly and noninvasively," said Dr. Silke Grabherr of the Institute of Forensic Medicine at the University of Lausanne.

The technique is suitable for the examination of large cargos or confirmation of suspicions without compromising packaging, Grabherr said.

Cocaine is the primary contraband candidate because it shows x-ray attenuation.

"When a carton of wine bottles contains the same wine, the bottles will generally have the same mean attenuation on cross-sectional images," Grabherr said. "It can be considered suspicious when the attenuation of some bottles differs from the others."

MSCT is also applicable to other sorts of smuggling, such as contraband hidden inside small sculptures or hollowed fruit, Grabherr said.

"Using CT and measuring the mean opacity of the content, differences in hidden drugs can be detected without destroying the carrier," she said.

Grabherr isn't necessarily recommending that expensive MSCT units be deployed at all border stations.

"To employ our method, collaboration between police or customs officials and a hospital radiology department or imaging center is necessary," she said.

Scanning can be performed at any facility with a CT modality.

Grabherr said cocaine detection in her test was achieved with a Somatom Sensation 6 scanner (Siemens Medical Solutions). Scanning parameters were 0.5-mm detector collimation, 0.63-mm slice width, a reconstruction increment of 0.5 mm, and a B30 kernel. Data evaluation was performed on 2D and 3D reconstructions.

"If a forensic chemistry department must analyze a confiscated shipment suspected of containing dissolved cocaine or other drug, the screening scan can be helpful to get a first overview to sort out suspicious vessels so more expensive quantitative chemical analysis can be performed on selected items," Grabherr said.

The question that initiated the experiments was whether it is possible to perform a screening examination on liquids in bottles suspected of containing dissolved cocaine without opening the bottles.

"The results show this to be an accurate technique," she said.