Ground glass nodules: CT-epidemiological analysis of growth patterns

Objectives: To quantify growth patterns of solitary pure ground glass nodules and to relate these pattern to epidemiological factors. Methods/Materials: Between 2008 and 2011, 95 patients were diagnosed on CT with solitary pure ground glass nodule (pGGN) at our hospital. CT features of pGGNs were evaluated at an initial and a follow-up CT. pGGNs were divided into “persisting” or “resolved”. Persisting nodules were further classified according to potential changes in total or solid component diameter into “decreased”, “unchanged”, and “increased”. Clinical and demo- graphic data were recorded. Association of data with morpho- logical pGGNs characteristics were tested with Kruskall-Wallis test and logistic regression. Results: After a median follow up of 16 months, 19/95 (20%) pGGNs resolved and 76/95 (80%) persisted. Of the persisting pGGNs, 51/76 (67.1%) were unchanged, 18/76 (23.7%) increased in size, and 7/76 (9.2%) decreased. Growth was more likely with age Z 67 years and a diameter Z 10 mm (OR 4.636; p=0.016). No significant relation was found between pGGNs growth and gender, history of cancer, or pGGN location. pGGN resolution was more likely with age <67 (OR 3.28; p = 0.04). No difference in diameter was found between resolved and persisting pGGNs (p = 0.21). Conclusions: Persisting larger solitary pGGNs were more likely to grow than smaller pGGNs. Moreover, pGGN growth was more likely to occur in older than in younger patients. This observation could help to fine-tune future follow-up recommendations for pGGNs with regard to the seemingly paradoxical influence of patient age.