reply to “use of ultrasound in the detection of intestinal drug smuggling”
TRANSCRIPT
Received: 2 June 2004Accepted: 1 July 2004Published online: 28 September 2004© Springer-Verlag 2004
This reply refers to the Letter to the Editorat http://dx.doi.org/10.1007/s00330-004-2468-0
Sir,Please find enclosed our response to the comments of Dr Howard andco-workers.
We would like to thank Dr Howardand co-workers for their constructiveremarks concerning our paper onidentification of intestinal drug con-tainers by ultrasound [1]. We agreewith Dr Howard that 84% of all pa-tients considered were positive dur-ing incarceration and that the infer-ence of our findings is limited to thisgroup. However, in the discussionpart of the paper we indicated thatfuture studies among subjects with alower a priori probability of havingan intestinal drug container presentshould be performed.
The properties of an ideal screen-ing test should be a high positivepredictive value and a high negativepredictive value. Since that is not often encountered, more emphasisgoes to either one, depending on theconsequences of a low positive pre-dictive value (many subjects will beincarcerated who did not swallowdrug containers) versus a low nega-tive predictive value (many subjectswith a negative test actually had in-testinal drug containers). In our pa-per, we emphasised a high positivepredictive value at a cost of lower
negative predictive value. However,please note that the number of nega-tive subjects was small and thus theprecision of the estimate of the nega-tive predictive value was limited. It is worthwhile to know that bothfalse negatives refer to so-called“pushers,” and the lower rectum area was initially not part of the scanprotocol.
Again, we feel that ultrasoundtesting, even in the absence of a goldstandard, should be further evaluatedin large populations with varyingprobabilities of intestinal drug con-tainers being present. One way ofdoing this is the construction of several populations comprising of“potential smuggles” and subjectsknown to have no intestinal drugscontainer. Of course, the sonogra-pher needs to be blinded with re-gards to the study design and who is who. In such an approach, the value of ultrasound in the detectionof intestinal drug smugglers can beexamined in a valid manner.
References
1. Meijer R, Bots ML (2003) Detection ofintestinal drug containers by ultrasoundscanning: an airport screening tool? EurRadiol 13:1312–1315
Eur Radiol (2005) 15:194DOI 10.1007/s00330-004-2469-z L E T T E R T O T H E E D I T O R
M. L. BotsR. L. Meijer
Reply to “Use of ultrasound in the detection of intestinal drug smuggling”
M. L. Bots · R. L. Meijer (✉)Department of Radiology E 01335,University Medical Center Utrecht,Heidelberglaan 100, 3508 GA Utrecht, The Netherlandse-mail: [email protected].: +31-30-2509111Fax: +31-30-2513399