Pallavi Mannam, Murali Arunan, Periakaruppan Gokulakrishnan, Easwaramoorthy Venkatachalapathy, Mohanarangam Venkata Sai Pulivadula
Department of Nuclear Medicine and PETCT, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India.
Department of Radiology and Imaging Sciences, Sri Ramachandra Institute of Higher Education and Research, Chennai, Tamil Nadu, India.
Indian J Nucl Med. 2021 Oct-Dec;36(4):371-376. doi: 10.4103/ijnm.ijnm_74_21. Epub 2021 Dec 15.
Extranodal (EN) lymphomas involve sites other than lymph nodes (LNs), spleen, thymus, and the pharyngeal lymphatic ring. The highest standardized uptake value (SUV) max of the LN can aid in the diagnosis of EN site lymphomatous infiltrations over inflammation or infection especially when there are no contrast-enhanced computed tomography (CT) changes.
The purpose of this study was to find the significance of correlation between absolute SUVmax and mediastinal blood pool (mbSUVmax) and liver (lvSUVmax) normalized SUVmax of EN sites and the most fluorodeoxyglucose (FDG) avid LN in patients with primary and secondary EN involvement in Non-Hodgkin's and Hodgkin's Lymphoma.
This was a retrospective study of 70 patients with histopathologically proven lymphoma in whom 18F-FDG positron emission tomography CT was performed for pretherapy staging.
Images were used to detect EN sites of disease and SUVmax of mediastinal blood pool, liver, highest SUVmax LN, and highest SUVmax EN site were calculated.
Karl Pearson's coefficient of correlation (r) was used to correlate the highest SUV max of LN and EN site and corresponding highest blood pool corrected and liver corrected SUV max. In view of small sample size, -test for paired samples at 5% and 10% significance was conducted to validate the findings. Two-tailed -test for independent samples was also used to compare means of SUVmax values between data grouped according to gender and lymphoma subtype (Non-Hodgkin lymphoma and Hodgkin lymphoma).
= 0.54 for the highest LN SUVmax-highest EN SUVmax values and on further validation by one- and two-tailed paired -test at significance levels of 5% and 10%, = 0.00052 and 0.00103 respectively which denoted significant positive and moderate correlation. = 0.59 for highest LN lvSUVmax-highest EN vSUVmax and = 0.00032 and 0.00065 showing positive and moderate correlation. = 0 0.82 for highest LN mbSUVmax-highest EN mbSUVmax values and = 0.00034 and 0.00068 revealing positive and strong correlation.
Significant positive and strong correlation exists between nodal and EN mbsUVmax. This is stronger than the correlation between nodal and EN absolute SUVmax and lvSUVmax. Since normalization of lesion SUVmax to reference tissues reduces the variability of SUV, this can be a useful adjunct to determine whether high SUVmax of the EN site is due to lymphomatous infiltration.
结外淋巴瘤累及淋巴结、脾脏、胸腺和咽淋巴环以外的部位。淋巴结的最高标准化摄取值（SUV）最大值有助于诊断结外部位的淋巴瘤浸润，而非炎症或感染，尤其是在没有对比增强计算机断层扫描（CT）改变的情况下。
本研究的目的是找出原发性和继发性结外受累的非霍奇金淋巴瘤和霍奇金淋巴瘤患者中，结外部位的绝对SUV最大值与纵隔血池（mbSUVmax）和肝脏（lvSUVmax）标准化SUV最大值以及最摄取氟脱氧葡萄糖（FDG）的淋巴结之间的相关性意义。
这是一项对70例经组织病理学证实的淋巴瘤患者的回顾性研究，这些患者接受了18F-FDG正电子发射断层扫描CT进行治疗前分期。
利用图像检测疾病的结外部位，并计算纵隔血池、肝脏、最高SUV最大值淋巴结和最高SUV最大值结外部位的SUV最大值。
采用卡尔·皮尔逊相关系数（r）来关联淋巴结和结外部位的最高SUV最大值以及相应的最高血池校正和肝脏校正SUV最大值。鉴于样本量较小，进行了5%和10%显著性水平的配对样本t检验以验证结果。还使用独立样本的双尾t检验来比较根据性别和淋巴瘤亚型（非霍奇金淋巴瘤和霍奇金淋巴瘤）分组的数据之间的SUV最大值均值。
最高淋巴结SUV最大值与最高结外SUV最大值之间的r = 0.54，在5%和10%显著性水平下通过单尾和双尾配对t检验进一步验证，p值分别为0.00052和0.00103，表明显著正相关和中度相关。最高淋巴结lvSUV最大值与最高结外vSUV最大值之间的r = 0.59，p值为0.00032和0.00065，显示正相关和中度相关。最高淋巴结mbSUV最大值与最高结外mbSUV最大值之间的r = 0.82，p值为0.00034和0.00068，显示正相关和强相关。
淋巴结和结外mbSUV最大值之间存在显著正相关和强相关。这比淋巴结和结外绝对SUV最大值以及lvSUV最大值之间的相关性更强。由于将病变SUV最大值归一化到参考组织可降低SUV的变异性，这可作为确定结外部位高SUV最大值是否由淋巴瘤浸润引起的有用辅助手段。
