Use of Gadolinium in CT Pulmonary Angiography

The study will investigate patients with clinical suspicion for pulmonary embolism (PE) who have a contraindication to iodine based contrast. These patients normally get investigated with studies such as ultrasound and nuclear medicine studies but the fastest and preferred investigation is CT with contrast to look for filling defects in the pulmonary arteries. The investigators will assess whether gadolinium, which is currently used with MRI can be used with CT as an alternative effective contrast in diagnosis or exclusion of PE. A new type of CT scanner, a Dual Energy Scanner will be used to improve the visibility of Gadolinium contrast on CT.

Contrast enhancement with Gadolinium will be evaluated to assess its efficacy for diagnosis and exclusion of pulmonary embolism in a patient who previously would not have been investigated with CTPA due to an underlying allergy to contrast or other contraindication. If this proves beneficial, it will allow such patients to be investigated successfully with CTPA

Gadolinium enhancement will be performed using intravenous Dotarem[recommended dose of 0.2 mL/kg (0.1 mmol Gd/kg )]

agents will be administered intravenously and a CT scan will be performed to evaluate contrast enhancement characteristics of the agents to assess their feasibility as an alternative to Iodine based contrast agents

Inclusion Criteria: Patients suspected of having a Pulmonary embolus Allergy to Iodine based intravenous contrast Exclusion Criteria: Renal impairment Less than 20 years of age Non-English speaking Pregnancy Allergy to Gadolinium