ULTRASOUND CONTRAST AGENT DELIVERED PER OS FIRST DIAGNOSES PHARYNGOESOPHAGEAL TUMOUR

have been used extensively during the last years for imaging various parts of the body. Their commonest way of administration is intravenously. However, they have also been given intracavitarily for specific indications. Oral administration of these agents has been described so far in medical literature only as work in progress. As far as we know, this is the first case report in which oral administration of a US contrast agent has aided in the patient’s diagnosis. We present the case of a patient with a cervical mass, in whom the clinical diagnosis before sonography was that of a thyroid goiter and computed tomography (CT) diagnosis was that of a cervical abscess. Oral administration of SonoVue (sulphur hexafluoride) led to directing sonographic diagnosis to that of a pharyngeal tumour. This was confirmed on barium swallow and endoscopy guided biopsy.

Ultrasound (US) contrast agents have been used extensively during the last years for imaging various parts of the body.Their commonest way of administration is intravenously.However, they have also been given intracavitarily for specific indications.Oral administration of these agents has been described so far in medical literature only as work in progress.As far as we know, this is the first case report in which oral administration of a US contrast agent has aided in the patient's diagnosis.We present the case of a patient with a cervical mass, in whom the clinical diagnosis before sonography was that of a thyroid goiter and computed tomography (CT) diagnosis was that of a cervical abscess.Oral administration of SonoVue (sulphur hexafluoride) led to directing sonographic diagnosis to that of a pharyngeal tumour.This was confirmed on barium swallow and endoscopy guided biopsy.

Case report
A 25-year-old man presented to the Emergency Department of our Hospital complaining of dysphagia and weight loss (12 kg in 3 months).Physical examination revealed a cervical mass initially presumed to represent thyroid goiter.A cervical CT scan already performed had diagnosed a retropharyngeal abscess.Cervical US showed a soft tissue mass which displaced the thyroid anteriorly but did not arise from the gland otherwise normal parenchyma.This space occupying lesion contained gas and was sonographically presumed to originate from the deformed oesophagus.It showed areas of rich vascularity on color Doppler (Fig. 1).With the patient's placed.These findings were attributed to the presence of the mass and possibly of enlarged lymphnodes.Barium pooled in the piriform sinuses, as a result of abnormal pharyngeal motility.These findings were consistent with malignancy.
Two days later an upper gastrointestinal tract endoscopy examination was performed.The pharyngeal lumen appeared concentrically stenosed.Biopsy specimens were obtained.Pathology study diagnosed squamous cell carcinoma of the oesophagus, extending to the pharynx, of intermediate to high differentiation with keratinisation and infiltration of the chorion.informed consent, US contrast agent SonoVue was given per os (one drop in 20 mL of tap water).Subsequent US scan showed the contrast agent coursing along the pharynx and oesophagus.The lower pharyngeal and upper oesophageal wall was irregularly thickened and the lumen was stenosed (Fig. 2).
On the following day, a barium swallow examination showed a large mass occupying the lower pharynx at the level of the piriform sinuses and part of the upper oesophagus with irregular mucosal derangement (Fig. 3).The retropharyngeal space was increased and the hypopharynx was anteriorly dis-JBR-BTR, 2013, 96: 69-71.

Discussion
US contrast agents consist of gasfilled microbubbles contained in a shell of proteins, lipids or polymers (1).Their diameter is approximately 3-5 µm, (about the diameter of a red blood cell).They are usually administered intravenously and, being too big to pass through the endothelial vessel wall, they remain in the lumen of blood vessels (2).These agents are used extensively intravenously for the safe imaging investigation of many body organs with excellent toleration (3).For two of the most commonly used drugs containing perflutren and sulphur hexafluoride microspheres, there are very low rates of anaphylactoid reactions (1:7000 or 0.014%) (4-6).These are lower than the respective rates of CT contrast agent adverse reactions (0.035%-0.095%) (4,7,8).Intravenous contrast enhanced ultrasound (CEUS) is avoided as a precaution only in patients with serious cardiopulmonary compromise (9).
However, these drugs are also administered intracavitarily for specific indications, such as vesicoureteral reflux studies in children (10), follow up of renal transplant recipients (11) and percutaneous drainage procedures.They allow visualisation of the drainage duct location post intraductal injection, determining if a drainage duct is correctly positioned or obstructed, as well as depicting the shape of the biliary tree (12) and diagnosing biliary leakage post T-helpful to this patient by correctly redirecting his diagnostic path.
In conclusion, we believe that this case is an example suggesting the valuable usage of US contrast agents following other administration routes, besides intravenous injection.It is a fast, non-expensive and easy to perform examination which can aid to the patient's diagnostic pathway.tube removal (13).In general, US contrast agents can be instilled into any sonographically accessible body cavity, with other clinical applications including abscesses, pancreatic pseudocysts or other pancreatitis complications, intestinal or other fistulas, gastrooesophageal reflux, as well as stenoses of the gastric and intestinal lumen (14).So far, only work in progress in this field has been published (15).
Other examples of various administration methods of contrast agents in imaging include the use of low osmolality iodinated contrast media, such as iohexol, either intravenously (e.g. for contrast enhanced CT) or orally (e.g. for pass-through examinations of the gastrointestinal tract or bowel opacification in CT examinations) (16).
Since sulphur hexafluoride is manufactured for intravenous use and oral administration is off-label, this was explained to the patient who gave his consent.No adverse reaction occurred post oral administration of this US contrast agent.The diagnoses which had been suggested up to that point (thyroid goiter and abscess) changed immediately by imaging a pharyngeal/oesophageal mass causing narrowing of their lumen.The diagnosis was confirmed on the next day by barium swallow, while endoscopy-aided biopsy performed two days later resulted in specific definition of the tumour's histology.Therefore, oral administration of SonoVue proved E. Antypa, D.D. Cokkinos, I. Kalogeropoulos, D. Tomais, P.N.Piperopoulos 1 Oral administration of ultrasound contrast agents has been described very little so far in medical literature.These agents are mainly administered intravenously and, less commonly, intracavitarily.We present the case of a patient with a cervical mass in whom sonographic examination with per os administration of SonoVue led to the diagnosis of a pharyngoesophageal tumour.The diagnosis was confirmed on barium swallow and endoscopy-guided biopsy.Key-word: Ultrasound (US), contrast media.From: 1. Radiology Department, Evangelismos Hospital, Athens, Greece.Address for correspondence: Dr D.D. Cokkinos, M.D., Dorylaiou 5, 11521 Athens, Greece.E-mail: ddcokkinos@yahoo.gr

Fig. 1 .
Fig. 1. -Transverse US scan of the cervix shows a large mass with focal areas of rich vascularity.It does not arise from the thyroid but displaces it anteriorly (arrows).

Fig. 2 .
Fig. 2. -Sagittal (left) and transverse (right) images of cervical US with oral administration of SonoVue.Irregular stenosis of the pharynx (arrow) and the upper oesophagus (double arrows) is noted.Curved arrow indicates normal oesophagus.

Fig. 3 .
Fig. 3. -Left sagittal (left) and frontal (right) radiographs obtained during barium swallow examination.A large mass displaces the pharynx anteriorly, with irregularity of the mucosa.Barium is pooling in the right (arrow) and left (curved arrow) piriform sinuses.