"Preparation familiarizes the patient with the equipment and the steps of the procedure, allows for any misconceptions to be addressed and teaches coping strategies, such as relaxation, when appropriate," wrote Dr. Cicero Jose Torres de Amorim e Silva and colleagues in their RSNA poster presentation. Silva's group is from the Royal Children's Hospital at the University of Melbourne.
While sedation or general anesthesia does improve cooperation and imaging results, there are inherent risks to the patient. In addition, administering drugs can be more costly because of additional time and staff, they stated.
"More importantly, (sedation and general anesthesia) do not give children a sense of mastery or control over the procedure," which can generate more fear and anxiety, the authors added.
The Royal Children's Hospital has a "practice MR unit," which is a full-scale reproduction of a 1.5-tesla scanner sans magnet. Pediatric patients are first read a storybook about MRI exams. They then go through an MRI rehearsal in which they must lie still in the scanner for at least five minutes. A CD of MR sounds is played insider the scanner during the practice session. The entire process can take anywhere from 30 minutes to one hour and is led by a nonimaging therapist.
If the patient can successfully lie still in the scanner, they are referred for an MR exam without sedation or general anesthesia.
Silva's group retrospectively reviewed the records of 134 children (median age of 7.7 years) who had been slated for an MR between February 2002 and April 2004. Each record was assessed as to whether the child had passed or failed the practice MR session. Those who passed went on to an actual exam, although any exams with motion artifacts were considered a failure.
Of the 134 children, 120 (90%) passed the practice exam. Of these 120, 98% (117) subsequently had a clinical MR scam without sedation or general anesthesia. Of these 117, 110 (94%) underwent successful clinical exams. The median age of these patients was 7.8 years. The median delay between the practice session and the actual MR scan was six days.
Silva's group stated that they found this method to be beneficial for children as young as 4 years old. In addition, the parents reported that the practice time gave the children better coping skills. The current policy at their institution is to offer practice MRI to all children older than 3 years of age.
In a discussion of his poster on Wednesday, Silva said that the cost of installing the mock MR system was about $8,000. However, his group has found that it can be cost-effective: In addition to reducing the number of patients who require sedation, this method shortens the wait time for those children who do require a MR scan with general anesthesia.
Poster session moderator Dr. Anne Paterson asked if Silva's group had looked at whether a long delay between the practice session and the actual MR scan resulted in any patients failing the final exam. Silva said his group is planning to do a prospective study, which will look at that issue.
By Shalmali Pal
AuntMinnie.com staff writer
November 30, 2005
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