Okada Masahiro, Shimono Taro, Komeya Yoshihiro, Ando Rina, Kagawa Yuki, Katsube Takashi, Kuwabara Masatomo, Yagyu Yukinobu, Kumano Seishi, Imaoka Izumi, Tsuchiya Norio, Ashikaga Ryuichiro, Hosono Makoto, Murakami Takamichi
Department of Radiology, Kinki University School of Medicine, 377-2 Ohno-Higashi, Osaka-Sayama, Osaka, 589-8511, Japan.
Ann Nucl Med. 2009 Jun;23(4):349-54. doi: 10.1007/s12149-009-0246-4. Epub 2009 Apr 2.
To investigate whether integrated fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) can differentiate benign from adrenal malignant lesions on the basis of maximum standardized uptake value (SUV(max)), tumor/liver (T/L) SUV(max) ratio, and CT attenuation value (Hounsfield Units; HU) of unenhanced CT obtained from FDG-PET/CT data.
We studied 30 patients with 35 adrenal lesions (16 adrenal benign lesions, size 16 +/- 5 mm, in 15 patients; and 19 adrenal malignant lesions, 24 +/- 12 mm, in 15 patients) who had confirmed primary malignancies (lung cancer in 23 patients, lymphoma in 2, esophageal cancer in 2, hypopharyngeal cancer in 1, prostate cancer in 1, and 1 patient in whom lesions were detected at cancer screening). All patients underwent PET/CT at 1 h post FDG injection. Diagnosis of adrenal malignant lesions was based on interval growth or reduction after chemotherapy. An adrenal mass that remained unchanged for over 1 year was the standard used to diagnose adrenal benign lesions. Values of FDG uptake and CT attenuation were measured by placing volumetric regions of interest over PET/CT images. Adrenal uptake of SUV(max) >/= 2.5 was considered to indicate a malignant lesion; SUV(max) < 2.5 was considered to indicate a benign lesion. In further analysis, 1.8 was employed as the threshold for the T/L SUV(max) ratio. Unenhanced CT obtained from PET/CT data was considered positive for adrenal malignant lesions based on a CT attenuation value >/= 10 HU; lesions with a value < 10 HU were considered adrenal benign lesions. Mann-Whitney's U test was used for statistical analyses.
SUV(max) in adrenal malignant lesions (7.4 +/- 3.5) was higher than that in adrenal benign lesions (2.1 +/- 0.5, p < 0.05). The CT attenuation value of adrenal malignant lesions (27.6 +/- 11.9 HU) was higher than that of adrenal benign lesions (10.1 +/- 12.3 HU, p < 0.05). In differentiating between adrenal benign and malignant lesions, a CT threshold of 10 HU corresponded to a sensitivity of 57%, specificity of 94%, accuracy of 74%, positive predictive value of 92% and negative predictive value of 65%. An SUV(max) cut-off value of 2.5 corresponded to a sensitivity of 89%, specificity of 94%, accuracy of 91%, positive predictive value of 94% and negative predictive value of 88%. The T/L SUV(max) ratio was 1.0 +/- 0.2 for adrenal benign lesions and 4.5 +/- 3.0 for adrenal malignant lesions. And T/L SUV(max) ratio cut-off value of 1.8 corresponded to a sensitivity of 85%, specificity of 100%, accuracy of 91%, positive predictive value of 100% and negative predictive value of 83%.
FDG-PET/CT with additional SUV(max) analysis improves the diagnostic accuracy of adrenal lesions in cancer patients.
探讨综合氟脱氧葡萄糖-正电子发射断层扫描/计算机断层扫描（FDG-PET/CT）能否根据最大标准化摄取值（SUV(max)）、肿瘤/肝脏（T/L）SUV(max)比值以及从FDG-PET/CT数据中获取的平扫CT的CT衰减值（亨氏单位；HU）来区分肾上腺良性和恶性病变。
我们研究了30例患有35个肾上腺病变的患者（15例患者中有16个肾上腺良性病变，大小为16±5mm；15例患者中有19个肾上腺恶性病变，大小为24±12mm），这些患者已确诊为原发性恶性肿瘤（23例为肺癌，2例为淋巴瘤，2例为食管癌，1例为下咽癌，1例为前列腺癌，1例在癌症筛查时发现病变）。所有患者在注射FDG后1小时接受PET/CT检查。肾上腺恶性病变的诊断基于化疗后的间隔期生长或缩小情况。肾上腺肿块1年以上保持不变是诊断肾上腺良性病变的标准。通过在PET/CT图像上放置体积感兴趣区来测量FDG摄取值和CT衰减值。肾上腺SUV(max)≥2.5被认为提示恶性病变；SUV(max)<2.5被认为提示良性病变。在进一步分析中，采用1.8作为T/L SUV(max)比值的阈值。从PET/CT数据中获取的平扫CT，基于CT衰减值≥10HU被认为肾上腺恶性病变为阳性；值<10HU的病变被认为是肾上腺良性病变。采用曼-惠特尼U检验进行统计分析。
肾上腺恶性病变的SUV(max)（7.4±3.5）高于肾上腺良性病变（2.1±0.5，p<0.05）。肾上腺恶性病变的CT衰减值（27.6±11.9HU）高于肾上腺良性病变（10.1±12.3HU，p<0.05）。在区分肾上腺良性和恶性病变时，CT阈值为10HU时，敏感性为57%，特异性为94%，准确性为74%，阳性预测值为92%，阴性预测值为65%。SUV(max)临界值为2.5时，敏感性为89%，特异性为94%，准确性为91%，阳性预测值为94%，阴性预测值为88%。肾上腺良性病变的T/L SUV(max)比值为1.0±0.2，肾上腺恶性病变的T/L SUV(max)比值为4.5±3.0。T/L SUV(max)比值临界值为1.8时，敏感性为85%，特异性为100%，准确性为91%，阳性预测值为100%，阴性预测值为83%。
进行额外SUV(max)分析的FDG-PET/CT可提高癌症患者肾上腺病变的诊断准确性。
