Description

A 43-year-old woman underwent a video fluoroscopic swallowing study as a part of evaluation for dysphagia during which 10 mL of iohexol (Omnipaque) was given as a contrast medium. As the patient aspirated some of the contrast medium, the procedure was abandoned immediately. She maintained an arterial oxygen saturation of 95% in room air. Chest radiographs showed tracking of the contrast along the bronchi of both lower lobes showing a classical ‘bronchography’ (figure 1A). The patient was treated with intravenous piperacillin+tazobactam and clindamycin for aspiration pneumonia and chest physiotherapy. She was discharged after 7 days with no symptoms. At follow-up 2 weeks later, she was doing well with a repeat chest radiograph showing clearance of the radiocontrast deposits (figure 1B) and contrast-enhanced CT imaging of the lungs revealing residual contrast deposition in the distal bronchi of both lower lobes (figure 1C).

• Download figure
• Open in new tab
• Download powerpoint

Figure 1

(A) Chest radiograph postcontrast swallow showing tracking of contrast along bilateral lower lobe bronchi. (B) Follow-up chest radiograph done 2 weeks later showing clearance of radiocontrast deposits. (C) Axial contrast-enhanced CT showing multiple centrilobular nodules in bibasal segments with ‘tree in bud’ appearance, showing high attenuation in the range of iodinated contrast.

Oral contrast agents are used for studies of the gastrointestinal tract such as pharyngography, esophagography, upper gastrointestinal studies and small-bowel follow-through examinations. The two categories of contrast used in such studies are barium sulfate suspensions and water-soluble iodinated contrast media. The water-soluble contrast media are divided into two types: high-osmolar contrast media (HOCM) and low-osmolar contrast media (LOCM) . The two currently available HOCMs are Gastrografin and Gastroview. LOCMs are generally supplied for intravenous use, and their use in oral contrast studies is considered ‘off label’ apart from iohexol (Omnipaque), which has US Food and Drug Administration approval for the same.1

Aspiration of contrast medium is a common complication of oral contrast fluoroscopy and is seen in up to 22% of fluoroscopic examinations.2 Such aspiration occurs more frequently in children and is associated with serious adverse reactions such as chemical pneumonitis and acute respiratory distress syndrome. These adverse reactions are especially prominent in HOCM, in which the high osmolality draws water into the alveoli, resulting in pulmonary oedema.1 Barium sulfate, in comparison, is relatively inert and is cleared by the alveolar cilia. However, in lungs with damaged epithelium, it can accumulate and cause pneumonitis and fibrosis.1 Iohexol has an osmolality of around 322 mOsm/kg, which is comparable to plasma. This, coupled with its chemically inert nature, and water solubility reduce the risk of contrast-induced pneumonitis.3 In addition, the taste of iohexol and other LOCMs is considered more palatable, making them the preferred agents in aspiration-prone patients.1

The management of oral contrast aspiration is usually conservative; however, severe cases may require oxygen support or intubation and mechanical ventilation. There are no standard guidelines for treating oral contrast aspiration and no data regarding the use of antibiotics in such aspiration. It is prudent that every radiology department has a mechanism for evaluating and treating this contrast-related adverse event. This case is being reported for its classical image of ‘bronchography’ in chest radiograph following aspiration of a small amount of LOCM iohexol during the video fluoroscopic swallowing study for the evaluation of dysphagia. Our patient had complete recovery with symptomatic treatment. Earlier recognition of this adverse event and obtaining appropriate imaging is critical in successful treatment of the patient.