Table 1.

Criteria for nodal involvement and ROC analysis

Imaging modalityCriteria for nodal involvement
MRISize ratio criteriaa (9, 12)
Benign: nodes less than 8 mm short axis
Malignant: nodes >10 mm short axis and round nodes >8 mm (ratio of the short to long axis >0.8)
[11C]Choline PETFocal uptake outside the normal physiologic distribution of tracer in locations corresponding to nodal chains
[11C]Choline PET-CTNodes with increased tracer uptake above the background, even when <10 mm in short-axis diameter
5 point scale for ROC analysis
ScaleMRI[11C]Choline PET/PET-CTb
1Nodes <4 mm or not seenDefinitely normal
2Nodes = 4–5.9 mmProbably normal (more likely to be physiologic)
3Nodes = 6–7.9 mmIndeterminate (equally physiologic/pathologic)
4Nodes ≥8 mm but <10 mmProbably abnormal (more likely to be pathologic)
5Nodes ≥10 mmDefinitely malignant
  • aShort-axis and long-axis diameters of the identifiable LNs were measured using electronic calipers on the scanner console.

  • bDefinitely normal, probably normal, and indeterminate were considered benign and probably abnormal and definitely abnormal were considered malignant.