Developments in spiral computed tomographic (CT) technology with multiple detector arrays enable submillimeter spatial resolution. Spiral CT performed after intraarticular injection of iodinated contrast material represents a valuable imaging modality for the assessment of internal derangements of the knee. Spiral CT arthrography has a high value for the detection of meniscal lesions including substance loss (altered contour), tear (intrameniscal contrast material) and meniscal separation (contrast material between meniscus and capsule). Displaced meniscal fragments are observed in intercondylar space, in superior and inferior recesses of the medial meniscus and in the femoro-tibial space. Anterior cruciate ligament and medial collateral ligament lesions consist of ligament interruption with contrast material in ligament defect. Spiral CT arthrography enables analysis of cartilage thickness and focal substance loss of all articular surfaces of the knee. The analysis of the cartilage lesion is relatively easy because of the high contrast between cartilage defect filled by the high density positive contrast material and low density of normal adjacent cartilage. Spiral CT arthrography has a high accuracy for deep substance loss but a very low accuracy for detection of superficial fibrillation.