Bhabha Atomic Research Centre (BARC), Tata Memorial Hospital Annexe, Radiation Medicine Centre, Bombay, India.
Bhabha Atomic Research Centre (BARC), Tata Memorial Hospital Annexe, Radiation Medicine Centre, Bombay, India.
Semin Nucl Med. 2017 Jul;47(4):373-391. doi: 10.1053/j.semnuclmed.2017.02.009. Epub 2017 Apr 19.
In this review, we summarize the false-positive and false-negative results of standard F-FDG-PET/CT in characterizing musculoskeletal lesions and discussed the added value and limitations of dual-time point imaging (DTPI) and delayed imaging in differentiating malignant from benign musculoskeletal lesions, based on review of the peer-reviewed literature. The quantitative and semiquantitative parameters adopted for DTPI are standardized uptake value (mainly maximum standardized uptake value [SUVmax]) and retention index (RI), calculated as RI (%) = 100% × (SUV [maxD-Delayed] - SUV [maxE-Early])/SUV [maxE-Early], although the criteria and cutoff for diagnosing malignancy in studies have varied considerably. Also, there has been considerable heterogeneity in protocol (time point of delayed imaging), interpretation, and results in dual-time point (DTP) F-FDG-PET for differentiating malignant from benign musculoskeletal lesions in various research studies. The specificity of DTPI is a function of many factors such as the nature of the musculoskeletal lesion or malignancy in question, the prevalence of false-positive etiologies in the patient population, and the cutoff values (either SUVmax or RI) employed to define a malignancy. Despite the apparent conflicting reports on the performance, there have been certain common points of agreement regarding DTPI: (1) DTP PET increases the sensitivity of F-FDG-PET/CT due to continued clearance of background activity and increasing F-FDG accumulation in malignant lesions, when the same diagnostic criteria (as in the initial standard single-time point imaging) are used. Increased sensitivity for lesion detection can be viewed as a strong point of DTP and delayed-time point imaging. (2) The causes for false positives (such as active infectious or inflammatory lesions and locally aggressive benign tumors) and false negatives (eg, low-grade sarcomas) are the major hurdles accounting for reduced diagnostic value of the technique, with overlap of F-FDG uptake patterns between benign and malignant musculoskeletal lesions on DTPI. (3) DTPI, however, could still be potentially useful in increasing the confidence of interpretation such as differentiating malignancy from sites of inactive or chronic inflammation, post-treatment viable residue vs necrosis, and certain other benign lesions. (4) Consideration of diagnostic CT component of PET/CT and the patient's clinical picture can lead to increase in specificity of interpretation in a given case scenario. Further systematic research, adoption of uniform protocol, and interpretation criterion could evolve the specific indications and interpretation criteria of DTPI for improved diagnostic accuracy in musculoskeletal lesions and its clinical applications.
在这篇综述中，我们总结了标准 F-FDG-PET/CT 在特征化肌肉骨骼病变中的假阳性和假阴性结果，并讨论了双时相成像（DTPI）和延迟成像在区分恶性和良性肌肉骨骼病变中的附加价值和局限性，这是基于对同行评议文献的回顾。用于 DTPI 的定量和半定量参数包括标准化摄取值（主要是最大标准化摄取值 [SUVmax]）和保留指数（RI），RI（%）=100%×（SUV[maxD-延迟] - SUV[maxE-早期]）/SUV[maxE-早期]，尽管研究中用于诊断恶性肿瘤的标准和截止值差异很大。此外，在不同的研究中，用于区分恶性和良性肌肉骨骼病变的双时相（DTP）F-FDG-PET 的方案（延迟成像的时间点）、解释和结果存在相当大的异质性。DTPI 的特异性是许多因素的函数，例如所考虑的肌肉骨骼病变或恶性肿瘤的性质、患者人群中假阳性病因的流行率以及用于定义恶性肿瘤的截止值（SUVmax 或 RI）。尽管关于 DTPI 的性能存在明显相互矛盾的报告，但在以下方面存在某些共识：（1）由于在使用相同的诊断标准（与初始标准单时相成像相同）时，背景活性的持续清除和恶性病变中 F-FDG 积累的增加，DTP PET 提高了 F-FDG-PET/CT 的敏感性。病变检测的敏感性增加可以被视为 DTP 和延迟时间点成像的一个优点。（2）假阳性（如活跃的感染或炎症性病变和局部侵袭性良性肿瘤）和假阴性（如低度肉瘤）的原因是导致该技术诊断价值降低的主要障碍，在 DTP 上良性和恶性肌肉骨骼病变之间存在 F-FDG 摄取模式的重叠。（3）然而，DTPI 仍然可以潜在地有助于增加解释的信心，例如将恶性肿瘤与非活动或慢性炎症部位、治疗后存活残留与坏死以及某些其他良性病变区分开来。（4）考虑 PET/CT 的诊断 CT 成分和患者的临床情况可以提高特定病例情况下解释的特异性。进一步的系统研究、采用统一的方案和解释标准，可以为提高肌肉骨骼病变的诊断准确性及其临床应用提供 DTPI 的具体适应证和解释标准。
