Friday, May 15, 2009

Imaging analysis in clinical trial

Medical imaging has now been a critical part in clinical trials. It can be used in many aspects of clinical trial process:
1) Disease diagnosis as part of inclusion/exclusion criteria
2) Safety assessment
3) Clinical efficacy endpoint

There are many medical imaging technologies. Here are just a list of some:
1) x-ray
2) CT scan
3) MRI
4) PET scan
5) Ultrasound
6) arteriogram or angiography
7) venogram

There is benefit and risk in using the medical imaging in clinical trials. Some imaging can pose extra safety issues. For example, x-ray, CT scan, PET scan can put the study subjects at extra radiological exposure. Arteriogram and CT/A can expose the subjects to additional contrast medium or dyes which may have its own safety issue.

Medical imaging is always a surrogate endpoint. The technician plays the important role in obtaining the imaging. The standardization and calibration are always important in order to obtain the reliable data especially in longitudinal studies. The interpretation of the imaging results depend on who read the imaging. There could be substantial variation between different readers. Therefore, the central reading is very important if the medical imaging is used in clinical trial. There are quite some articles discussing the imaging in clinical trials in the Applied Clinical Trial magazine.

There are several specialty medical imaging vendors on the market. Some of them are listed below:
1) BioClinica or Bio-imaging
2) Biomedical Systems
3) Perceptive (part of Parexel)
4) Synarc

FDA and EMEA has issued several guidance on imaging used in clinical trial. For example:

1) FDA Guidance "Standards for Clinical Trials Imaging Endpoints"
This guidance discussed the clinical trials with imaging endpoints - i.e., the reading from medical imaging is used as the efficacy endpoint. Examples are: RECIST criteria for assessing the tumor size for solid tumor based on FDG-PET or MRI. Lung density measure by CT scan to assess emphysema.

2) FDA guidance Developing Imaging Drug and Biological Products,

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