Hidden scars

日期:2019-03-07 05:05:01 作者:方揉 阅读:

By Philip Cohen IS IT possible to diagnose the human form of BSE with a simple brain scan? One radiologist thinks it should be, and Britain’s official unit for monitoring emerging cases of new variant Creutzfeldt-Jakob disease (vCJD) is separately pursuing a similar approach. Diagnosing vCJD is difficult. Usually, confirmation only comes at autopsy, where the disease can be recognised by the trail of holes and deposits of rogue prion protein that it leaves in the brain. But another sign is scarring of a region deep in the brain called the posterior thalamus. This scarring shows up as increased signal intensity on magnetic resonance images (MRI) of the brain, and isn’t seen in forms of CJD not linked to the consumption of BSE-infected meat. The problem, explains radiologist Alan Coulthard of the Royal Victoria Infirmary in Newcastle upon Tyne, is that it takes an experienced eye to see that the signal from the posterior thalamus is “unusually” intense. “That is hard experience to get when you may see only one case of vCJD in several years,” he says. Coulthard and his colleagues decided to develop a standardised method to read the MRI scans. They obtained scans from three patients diagnosed with vCJD and 14 controls with no neurological problems. When they compared the intensity of the MRI signal from the posterior thalamus to that of either the putamen or the caudate—two neighbouring brain regions—the signal from the posterior thalamus was less intense in all the normal subjects and more intense in each of the vCJD patients (The British Journal of Radiology, vol 72, p 749). “It’s pretty impressive,” says Martin Zeidler, formerly of the National CJD Surveillance Unit in Edinburgh. But both he and Coulthard say that one small study can’t determine how reliable the test is or how early in the course of the disease it can be used. Zeidler and his colleagues hope to answer such questions, however,