The usefulness of labelled white blood cells in diagnosing necrotizing external otitis

Early intervention is key when dealing with the rare but serious disease of necrotizing external otitis (NEO). NEO is often caused by Pseudomonas aeruginosa, a persistent and easily encountered pathogen that primarily affects immunosuppressed and elderly patients. Though scintigraphy is touted as a gold standard for diagnosing NEO, a recent meta-analysis questions its validity due to low sensitivity and specificity. Here, Richard Salzman and his team from University Hospital Olomouc in the Czech Republic utilize ^99mTc-HMPAO labelled autologous leukocyte scintigraphy to confirm NEO and monitor the therapeutic response to treatment, providing a convenient and more reliable method of testing for this disease. 

 

Salzman and his team of researchers published results in Journal of Otology on July 27, 2026.

 

NEO, if not caught and treated, comes with a high morbidity rate. Therefore, positively identifying the disease early is imperative to an optimistic outcome for the patient. The disease usually starts in the ear canal and can travel inward to the skull or brain, causing infection of the bone (osteomyelitis) and potentially nerve damage or brain infections. While this disease can be treated, recurrence is common, making continued monitoring nearly as important as a swift diagnosis. A comorbidity associated with NEO is diabetes, though other immunodeficiency disorders are also found throughout studies.

 

 ^99mTc-HMPAO labelled autologous leukocyte scintigraphy uses a small amount of radiation to label the leukocyte (a type of white blood cell) to follow throughout the body, allowing for a two-dimensional image of the patient’s internal structures to be produced. Combined with SPECT/CT, another imaging technique that generates a three-dimensional image, a better image of the lesions are produced than scintigraphy alone can produce, as well as the current methods of MRI and CT. While both CT and MRI can be effective, false positives with MRI can be problematic. The specificity and sensitivity of scintigraphy can help to mitigate the shortcomings of MRI.

 

This small study used five patients, all male and within the age range of 51-84 years old. The patients were studied over the course of 12 years to monitor for recurrence of the disease. Within this group, scintigraphy confirmed all cases to be positive for NEO. In the monitoring phase, two true negatives, two false negatives and one false positive were confirmed. The results show a sensitivity of 100% for this study, with a negative predictive value of 88% and sensitivity of 86% specificity and 75% in monitoring. Additionally, in all patients, recurrence was truly detected or ruled out.

 

Negative predictive value is the probability that the result of a negative is a true negative, while the percent of sensitivity gives the rate of correct identifications for individuals with a disease, and specificity refers to the rate of correct identification of individuals tested who do not suffer from the disease in question.

 

Further investigation into the confirmation of results is necessary for the future work of ^99mTc-HMPAO leukocyte scintigraphy. Improving the estimated low predictive value of the method is also crucial in being able to correctly determine the difference between diseased and non-diseased results with higher accuracy upon the phase of disease monitoring.

 

“^99mTc-HMPAO-labelled autologous leukocytes scintigraphy is an appropriate method that establishes the primary diagnosis of NEO, detects and rules out a disease recurrence with an adequate accuracy and reliability,” said Richard Salzman, doctor at University Hospital Olomouc and author of the study.

 

Though the sample size of this study is small and some sampling bias is unavoidable, the usefulness of ^99mTc-HMPAO leukocyte scintigraphy shows a reliable method in diagnosing patients with NEO, and a promising way to monitor individuals with the disease throughout the years for recurrence and subsequent treatments.

 

Tomáš Bakaj, Libuš Quinn and Richard Salzman of the Faculty of Medicine and Dentistry at Palacký University Olomouc, with Tomáš Bakaj and Richard Salzman also of the Department of Otorhinolaryngology and Head and Neck Surgery at University Hospital Olomouc, and Libuš Quinn of the Department of Nuclear Medicine at University Hospital Olomouc contributed to this research.

 

The Ministry of Health, Czech Republic supported this research.

 

DOI Link:

https://doi.org/10.26599/JOTO.2026.9540064

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