Central imaging and ECG reading is a service in which one central team reads every scan and every ECG taken in a clinical trial, all in the same way. A scan is an image of the inside of the body, such as a CT or MRI. An ECG, or electrocardiogram, is a tracing of the heart's electrical activity. The company that does this is called a central reading or core lab.
Why not let each hospital read its own scans? In a trial with 60 hospitals, there would be 60 different radiologists, each with their own habits. One might measure a tumour at 30 mm and another at 34 mm. The difference would be noise, not the medicine's effect. A central team using one method removes that noise. Its readers are also blinded. They do not know which patient got which medicine.
Consider a lung cancer trial at 60 hospitals in India, Poland and South Korea. Every eight weeks, each patient has a CT scan at their own hospital. The hospital exports the scan from its PACS, the system that stores its scans, and uploads it to the central reader's system. Two radiologists, working separately, measure the same tumours. They follow a fixed rulebook called RECIST. For one patient, the main tumour has shrunk from 42 mm to 28 mm, a fall of 33%. Under RECIST, a fall of at least 30% counts as a partial response, which means the tumour is responding. If the two radiologists disagree, a third radiologist decides. The result goes to the clinical trial data platform.
The second job is heart safety. Some medicines change the rhythm of the heart. One warning sign is a longer QT interval, a part of the ECG tracing. Each hospital sends its ECGs to the central team. Specialists measure every tracing in the same way, often with software that makes a first measurement. If a patient's corrected QT interval goes above 500 milliseconds, the team alerts the trial doctor at once. Reading ECGs from far away is the same idea as remote ECG interpretation, but done to a trial's fixed rules.
Every measurement is recorded with an audit trail, as GxP rules require, because the regulator may ask how each result was reached. The ordinary reading of a scan in a hospital is described in medical imaging.