Follow-Up CT Can Be Effective When Abdominal Ultrasound Findings Unclear

Approximately 33% of CT scans performed following an inconclusive abdominal ultrasound examination have positive findings, according to a study of 449 patients.

Opinions differ as to the need and applicability for further diagnostic imaging workup after an inconclusive abdominal ultrasound examination, according to Supriya Gupta, MD, from at Massachusetts General Hospital (Boston, MA, USA), and one of the authors of the study. “Our study found that 32.9% of follow-up CT examinations had positive findings, while 42.7% had findings that were not significant and 11.7% were equivocal. The remaining 12% had incidental findings; meaning, significant findings but not related to the clinical indication for the exam, said Dr. Gupta.

“While only about 33% of the CT examinations had positive findings it doesn’t mean that the other CT exams were not valuable as sometimes even negative exams add a lot to patient management,” noted Dr. Gupta.

The study revealed that follow-up CT was most beneficial in diagnosing renal lesions. The positivity rate for CT was 87.5% for renal cysts and 81.8% for renal stone, according to Dr. Gupta. Renal cysts and renal stone were two of the more typical indications for recommending follow-up CT. The CT scan had the least value as a follow up exam for indeterminate pancreatic and intestinal masses on ultrasound, with a less than 10% positivity rate, reported Dr. Gupta.

The study findings emphasized that the benefits of CT as a follow-up to inconclusive ultrasound examinations need to be more carefully reviewed; standardized guidelines for the use of follow-up CT need to be developed because the use of CT has cost and radiation implications, according to Dr. Gupta.

The study’s findings were presented at the American Roentgen Ray Society annual meeting, held April 2012 in Vancouver (BC, Canada).

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