title: Terminology inaccuracies in the interpretation of imaging results in detection of cervical lymph node metastases in papillary thyroid cancer.
abstract: Cervical lymph nodes (CLNs) are the most common site of metastases in papillary thyroid cancer (PTC). Ultrasound scan (US) is the most commonly used imaging modality in the evaluation of CLNs in PTC. Computerised tomography (CT) and (18)fluorodeoxyglucose positron emission tomography ((18)FDG PET-CT) are used less commonly. It is widely believed that the above imaging techniques should guide the surgical approach to the patient with PTC.
  
  
  METHODS
  We performed a systematic review of imaging studies from the literature assessing the usefulness for the detection of metastatic CLNs in PTC. We evaluated the author's interpretation of their numeric findings specifically with regard to 'sensitivity' and 'negative predictive value' (NPV) by comparing their use against standard definitions of these terms in probabilistic statistics.
  
  
  RESULTS
  A total of 16 studies used probabilistic terms to describe the value of US for the detection of LN metastases. Only 6 (37.5%) calculated sensitivity and NPV correctly. For CT, out of the eight studies, only 1 (12.5%) used correct terms to describe analytical results. One study looked at magnetic resonance imaging, while three assessed (18)FDG PET-CT, none of which provided correct calculations for sensitivity and NPV.
  
  
  CONCLUSIONS
  Imaging provides high specificity for the detection of cervical metastases of PTC. However, sensitivity and NPV are low. The majority of studies reporting on a high sensitivity have not used key terms according to standard definitions of probabilistic statistics. Against common opinion, there is no current evidence that failure to find LN metastases on ultrasound or cross-sectional imaging can be used to guide surgical decision making.
authors.affiliation: Department of Endocrine Surgery King's College Hospital Denmark Hill, London, SE5 9RS UK ; King's College London London UK.
authors.forename: Mubashir
authors.initials: M
authors.lastname: Mulla
authors.forename: Klaus-Martin
authors.initials: KM
authors.lastname: Schulte
keywords: CT; MRI; cervical lymph node; metastases; negative predictive value; papillary thyroid cancer; sensitivity; ultrasound