PET/CT薄层及延迟显像对低代谢肺实性小结节的诊断价值

Diagnostic value of PET/CT thin-slice and delayed imaging in low metabolism small pulmonary nodules

目的 探讨高分辨肺薄层成像及延迟显像对低代谢的肺实性小结节的诊断意义。方法 选择2020年1月至2022年1月在合肥京东方医院经病理诊断的低代谢的肺实性小结节患者21例,其中男性12例,女性9例;年龄41~85岁,平均年龄58.75岁;结节直径0.6~2.0 cm,平均直径1.17 cm;经病理诊断,良性13例,恶性8例。先行PET/CT常规显像,然后行肺薄层CT扫描及延迟显像,半定量法测定结节常规及延迟期最大标准摄取值(SUVmax),并分析延迟显像与常规显像SUVmax差值(ΔSUVmax),计算其诊断的灵敏度、特异度和准确度。所得结果分别与病理检查结果对照比较。结果 PET/CT常规加做薄层CT显像,两者联合的灵敏度为72.7%,特异度为86.7%,准确度为80.7%,明显高于单一者。与病理诊断结果对照,结合SUVmax差值分析,恶性病灶大多数ΔSUVmax≥常规显像的SUVmax100%,诊断准确度为87.5%;而良性病灶多数ΔSUVmax <常规显像的SUVmax100%,诊断准确度为84.6%。恶性肺实性小结节常规与延迟显像SUVmax平均值高于良性病变患者,差异有统计学意义(2.77±0.39 vs 1.67±0.38,4.78±0.42 vs 2.49±0.33。P <0.05);恶性结节的平均ΔSUVmax及差值率较良性结节显著增加,差异有统计学意义(2.12±0.31 vs 0.82±0.26,25.59±12.87 vs 8.72±5.59。P <0.05)。表明评估延迟显像ΔSUVmax及差值率能进一步提高准确度。结论 加做肺薄层CT扫描和同时实施PET/CT延迟显像可以显著提高低代谢的肺实性小结节的诊断准确度,尤其对于低代谢(SUVmax≤3.45)小结节的预测价值较高。

Objective To explore the diagnostic significance of high-resolution lung thin-slice imaging and delayed imaging for low metabolic pulmonary solid nodules. Methods From January 2020 to January 2022, a total of 21 patients with hypometabolic small solid pulmonary nodules confirmed by pathology were enrolled, which included 12 males and 9 females, aged41-85 years old with mean age of 58.75 years old;nodule diameter was 0.6-2.0 cm with mean diameter of 1.17 cm. According to pathological diagnosis, 13 cases were benign and 8 cases were malignant. The conventional PET/CT imaging was performed firstly, and then thin-slice CT scan and delayed imaging were performed. The conventional and delayed SUVmax values of nodules were measured by semi-quantitative method, and the difference between delayed imaging and conventional imaging SUV(ΔSUVmax) was analyzed. The sensitivity, specificity and accuracy of diagnosis were calculated. The results were compared with pathological findings. Results The sensitivity, specificity and accuracy of PET/CT combined with thin-slice CT were 72.7 %,86.7 % and 80.7 %, respectively, which were significantly higher than those of PET/CT alone. Compared with results of pathological diagnosis, combined with SUVmax difference analysis showed that the majority of malignant lesions ΔSUVmax ≥ conventional imaging SUVmax100 %, diagnostic accuracy was 87.5 %;most of benign lesions ΔSUVmax conventional imaging SUVmax100%, the diagnostic accuracy was 84.6 %. Compared with benign lesions, the mean SUVmax of conventional and delayed imaging of malignant solid pulmonary nodules was statistically significantly higher( 2. 77 ± 0.39 vs 1.67 ± 0.38, 4.78 ± 0.42 vs 2.49 ±0.33. P<0.05);the mean ΔSUVmax and difference rate of SUVmax of malignant nodules were significantly higher(2.12 ± 0.31 vs0.82 ± 0.26, 25.59 ± 12.87 vs 8.72 ± 5.59. P<0.05). Thus, evaluated ΔSUVmax and difference rate of SUVmax in delayed imaging further improved the diagnostic accuracy of solid pulmonary nodules. Conclusion It is demonstrated that combination of thinslice CT scan and delayed PET/CT scan could significantly improve the diagnostic accuracy of small solid pulmonary nodules with low metabolism, especially for small solid pulmonary nodules with low metabolism(SUVmax ≤ 3.45).