Computed tomographic pulmonary angiography (CTPA) is considered the gold standard for the diagnosis of pulmonary embolism (PE). PE is a potentially fatal disease in which a thrombus is lodged into a pulmonary artery blocking blood flow and potentially leading to respiratory distress, acute right cardiac failure or death. Therefore early and correct diagnosis is crucial.

The diagnostic and clinical value of CTPA has already been firmly substantiated. Unfortunately up to 7.3% of PE scans are still deemed to be non-diagnostic, for example due to insufficient contrast enhancement in the target arteries.

Therefore future research should focus on two important aspects of CT imaging. On the one hand optimal enhancement for the individual patient, on the other hand preventing additional risk of CT imaging - namely contrast induced nephropathy (CIN) and radiation risk. Thus the purpose of our study will be to optimize radiation dose settings (e.g. tube voltage, tube current) and CM application for the individual patient in CTPA.

Inclusion Criteria:

• Suspicion of pulmonary embolism

Exclusion Criteria:

• Severe allergy against Iopromide or any of the ingredients, previous severe CM reaction (according to current ESUR guidelines), renal insufficiency, pregnancy

Consecutive patients referred for CTPA with a clinical suspicion of pulmonary embolism will be included.