Nuclear Medicine Department, Universitary General Hospital, Ciudad Real, Spain.
Ann Nucl Med. 2010 Apr;24(3):207-14. doi: 10.1007/s12149-010-0345-2. Epub 2010 Feb 23.
To evaluate the effect of the 18F-FDG PET-CT respiratory gating (4D) study in the correct documentation of pulmonary lesions with faint uptake in standard PET-CT.
Forty-two pulmonary lesions with a low or no detectable uptake of FDG (SUV(max) < 2.5) in 3D PET-CT were prospectively evaluated in 28 patients (19 males and 9 females), mean age 66.5 years (41-81). 22 patients had neoplastic background. A conventional PET-CT (3D) total body scan was performed approximately 60 min after iv injection of a mean dose of 370 MBq. Furthermore, a 4D PET-CT (synchronized with respiratory movement) thorax study was acquired. SUV(max) was determined for each lesion in both studies. For the 4D studies, we selected the SUV(max) in respiratory period with the highest uptake ("best bin"). We calculated the SUV(max) percentage difference between 3D and 4D PET-CT (% difference = SUV(max) 4D - SUV(max) 3D/SUV(max) 3D x 100) and the relation of this value with the size and locations of the lesions. In 4D study, any lesion with SUV(max) > or = 2.5 was classified as malignant. We assessed the changes of lesion classification (from benign to malignant) applying the 4D technique. The final diagnosis was obtained by histological assessment or clinical and radiological follow-up longer than 12 months.
Forty out of 42 lesions showed an increase of SUV(max) in the 4D study with respect to 3D. The mean SUV(max) in the 3D and 4D PET-CT studies were 1.33 (+/-0.59) and 2.26 (+/-0.87), respectively. The SUV(max) percentage difference mean between both techniques was 83.3% (+/-80.81).The smaller the lesion the greater was the SUV(max) percentage difference (P < 0.05). No differences were observed depending on the location of the lesion. In 40% of cases, there was a change in the final classification of lesions from benign to malignant. In the final diagnosis, 24 lesions were malignant. 4D PET-CT diagnosed correctly the 52% of them.
The 4D PET-CT study permitted a better characterization of malignant lung lesions compared with the standard PET-CT, because of its higher sensitivity. 4D PET-CT is a recommendable technique in the early diagnosis of malignant lesions.
评估 18F-FDG PET-CT 呼吸门控（4D）研究在正确记录标准 PET-CT 中摄取微弱的肺部病变中的作用。
前瞻性评估 28 例患者（19 名男性和 9 名女性）中 42 个肺部病变的情况，这些病变在 3D PET-CT 中低或无 FDG 摄取（SUV(max) < 2.5），平均年龄 66.5 岁（41-81）。22 例患者有肿瘤背景。在静脉注射平均剂量 370MBq 后约 60 分钟进行常规 3D 全身 PET-CT 扫描。此外，还进行了 4D PET-CT（与呼吸运动同步）胸部研究。在两项研究中均确定了每个病变的 SUV(max)。对于 4D 研究，我们选择摄取最高的呼吸期的 SUV(max)（“最佳 bin”）。我们计算了 3D 和 4D PET-CT 之间 SUV(max)的百分比差异（%差异= SUV(max) 4D-SUV(max) 3D/SUV(max) 3D x 100），并将该值与病变的大小和位置相关联。在 4D 研究中，任何 SUV(max)>或=2.5 的病变均被归类为恶性。我们应用 4D 技术评估病变分类（从良性变为恶性）的变化。最终诊断通过组织学评估或临床和放射学随访 12 个月以上获得。
42 个病变中有 40 个在 4D 研究中 SUV(max)较 3D 增加。3D 和 4D PET-CT 研究中的 SUV(max)平均值分别为 1.33（+/-0.59）和 2.26（+/-0.87）。两种技术之间 SUV(max)的百分比差异平均值为 83.3%（+/-80.81）。病变越小，SUV(max)百分比差异越大（P < 0.05）。病变位置无差异。在 40%的病例中，病变的最终分类从良性变为恶性。在最终诊断中，24 个病变为恶性。4D PET-CT 正确诊断了其中的 52%。
与标准 PET-CT 相比，4D PET-CT 研究可以更好地对恶性肺病变进行特征描述，因为其敏感性更高。4D PET-CT 是恶性病变早期诊断的推荐技术。
