DETECTION OF PULMONARY METASTASES WITH PATHOLOGICAL CORRELATION - EFFECT OF BREATHING ON THE ACCURACY OF SPIRAL CT

Background. CT of the chest for suspected pulmonary metastases in adul ts is generally performed using a breath-hold technique. The results m ay not be applicable to young children in whom breath-holding may be i mpossible. Objective. Determine the effect of breathing on the accurac y of pulmonary metastasis detection by spiral CT (SCT). Materials and methods. Prior to euthanasia four anesthetized dogs with metastatic os teosarcoma underwent SCT with a collimation of 5 mm and a pitch of 2, during both induced breath-hold and normal quiet breathing. Images wer e reconstructed as contiguous 5-mm slices. Macroscopically evident met astases were noted at postmortem. Hardcopy SCT images were reviewed by ten radiologists, each of whom circled all suspected metastases. SCT images were compared with postmortem results to determine true and fal se positives. Results. The pathologist identified 132 macroscopically evident pulmonary metastases. For metastasis detection, there was no s ignificant difference between breath-hold SCT and breathing SCT. Concl usion. In our animal model, SCT can be performed during normal resting breathing without significant loss of accuracy in the detection of pu lmonary metastases.