Transient interruption of bolus contrast is a physiologic artefact due to a poor mixture of blood and contrast material. It is encountered when performing computed tomography pulmonary angiograms (CTPA). A working knowledge of this phenomenon is crucial to avoid a misdiagnosis of pulmonary embolism. A relatively high percentage (5-6%) of CTPA has been deemed inconclusive or technically insufficient due to poor contrast enhancement of the pulmonary arteries, which affects 40% of CTPAs. This case report describes this phenomenon and the setting in which it occurs. The patient’s clinical history, radiological findings, appearance, and possible countermeasures, are described.