Neuroscientist ZANG Yufeng and his colleaguesat Beijing Normal University plan to use functional magneticresonance imaging (fMRI) to probe differences in brain activitybetween healthy children and those with attention deficit hyperactivitydisorder. Intending to enroll children in the study, universitystudents last December handed out fliers at a primary school.But they came away empty-handed: Parents were worried that MRIscans might harm their children.
Although MRI is widely embraced in China as a diagnostic tool,parents are reluctant to expose children to strong magneticfields. Such unease is not the only impediment. "It's gettingharder to do MRI studies because public distrust of doctorsis increasing," says XIE Sheng, a radiologist here at Peking University First Hospital. Reasons for distrust include heightenedawareness of patients' rights and more debate in the media aboutthe relative merits of different treatments, she says. The challengeof recruiting healthy children for studies has compelled XIE, for one, to resort to ill children—an approach that canbackfire.
After 3 decades in the clinic, MRI is considered safer thanx-ray scans and proton emission tomography, says physicist YihongYang, chief of the MRI physics section at the National Instituteon Drug Abuse in Baltimore, Maryland. The main danger is forpeople with a pacemaker or other metal in their bodies. "Millionsof people have been examined with MRI so far; thus it seemsnow very unlikely that there would be a side effect," says Arno Villringer, director of cognitive neurology at the Max PlanckInstitute for Human Cognitive and Brain Sciences in Leipzig,Germany.
In China, that reassurance cuts little ice with many parents—andsome scientists. "I would not dare to allow my children to betested by MRI," says radiologist Han Hongbin of Peking UniversityThird Hospital. "Nobody can ensure that there is no potentialdanger," such as during nonroutine MRI scans that use extremelypowerful magnetic fields, he says.
In the face of such concerns, some researchers take shortcuts. For example, XIE recently submitted a report to Epilepsy Researchon epilepsy in toddlers. Last month, however, the journal rejectedher article because her control subjects were unhealthy. XIE acknowledges that's true: Most children she classified as controlshad undergone MRI exams for other complaints. "It is too hardto recruit perfectly healthy children to take an MRI test,"XIE says.
Some colleagues sympathize and suggest that exceptions to standardresearch practice should sometimes be allowed. ZANG says thatin XIE's case, children who are not afflicted with epilepsyand have no neurological complaints—but who may sufferfrom other ailments—are permissible controls. Not so,says HUANG Ruiwang, a magnetic resonance physicist at BeijingNormal, who argues that it was correct to reject Xie's article.
Recruitment goes more smoothly in the United States, where "manyparents will allow their children to take the test," says DamienFair, a neuroscientist at Oregon Health and Science Universityin Portland. Even in China, some groups have had more success.TAN Lihai, co-director of the State Key Laboratory of Brainand Cognitive Sciences at the University of Hong Kong, sayshe has never had trouble recruiting subjects for studies; histeam recently identified brain regions crucial for reading anddyslexia in Chinese children.
TAN's success heartens ZANG, who believes his group can getits study back on track. They will resume their recruitmentdrive after the Lunar New Year festival ends this week—although ZANG says that this time around they will work harder to betterinform parents about their research aims. (Science)
