Lack William, Donigan Jonathan A, Morcuende Jose, Buckwalter Joseph, El-Khoury Georges Y
Iowa Orthop J. 2010;30:76-9.
CT-guided biopsy is a minimally invasive diagnostic method of evaluating musculoskeletal lesions. Other options include incisional and excisional biopsy with the possibility of intraoperative frozen section. The clinician's decision to order a CT-guided biopsy requires an understanding of the likelihood that this biopsy will affect treatment This requires an understanding of both diagnostic yield and accuracy. Furthermore, the clinical utility of a biopsy is affected by factors other than the yield and accuracy as the clinical setting may render a technically diagnostic biopsy unhelpful.
A retrospective review of the electronic record at an orthopedic oncology referral center identified all patients who had undergone CT-guided percutaneous needle biopsy of musculoskeletal lesions after being evaluated by an orthopedic oncologist in clinic over a period of 5 years. 53 CT-guided biopsies of bone lesions and 16 CT-guided biopsies of soft tissue lesions were identified. The diagnostic yield (rate of obtaining tissue from which the pathologist could report a diagnosis) and clinical utility (rate at which biopsy results guided treatment decisions) were calculated and statistically compared.
The overall diagnostic yield of CT-guided bone biopsies was 94% (50 of 53 biopsies) and the clinical utility was 70% (37 of 53 biopsies). In the first 2 years of the study the diagnostic yield was 95% (21 of 22 biopsies) and the clinical utility was 86% (19 of 22 biopsies). In the remaining 3 years the diagnostic yield was 91% (28 of 31 biopsies) and the clinical utility was 58% (18 of 31 biopsies). This decrease in clinical utility over time was statistically significant (p = 0.01). Suspicion of metastasis resulted in a diagnostic yield of 100% (11/11) and a clinical utility of 91% (10/11). Suspicion of primary tumor resulted in a diagnostic yield and clinical utility of 93% (39/42) and 67% (28/42), respectively. This difference in clinical utility was statistically significant (p = 0.02). The diagnostic yield of CT-guided soft tissue biopsies was 75% (12 of 16 biopsies) and the clinical utility was 69% (11 of 16 biopsies). The diagnostic yield was significantly lower for soft tissue biopsy than bone biopsy (p = 0.01). There was no relationship between the rate of diagnostic biopsies and the evaluating pathologist or the location of the lesion within the body.
CT-guided biopsy is useful in the diagnosis of musculoskeletal lesions, however, its clinical utility is substantially lower than its diagnostic accuracy and yield due to a significant rate of diagnostic biopsies that fail to guide treatment, particularly when a primary lesion is suspected. The disparity in clinical utility based on preoperative suspicion of metastasis was even greater in our study than previously shown. CT-guided percutaneous needle biopsy is much more likely to guide treatment in the setting of suspected bone metastasis as opposed to biopsies of suspected primary bone lesions and soft tissue lesions.
CT引导下活检是评估肌肉骨骼病变的一种微创诊断方法。其他选择包括切开活检和切除活检，并有可能进行术中冰冻切片检查。临床医生决定进行CT引导下活检需要了解这种活检影响治疗的可能性。这需要了解诊断率和准确性。此外，活检的临床效用还受到除活检率和准确性之外的其他因素影响，因为临床情况可能使技术上诊断性的活检变得无用。
对一家骨科肿瘤转诊中心的电子记录进行回顾性研究，确定了在5年期间经骨科肿瘤医生在门诊评估后接受CT引导下经皮针吸活检肌肉骨骼病变的所有患者。共确定了53例骨病变的CT引导下活检和16例软组织病变的CT引导下活检。计算诊断率（病理学家能够报告诊断结果的取材率）和临床效用（活检结果指导治疗决策的比例）并进行统计学比较。
CT引导下骨活检的总体诊断率为94%（53例活检中有50例），临床效用为70%（53例活检中有37例）。在研究的前两年，诊断率为95%（22例活检中有21例），临床效用为86%（22例活检中有19例）。在剩余的3年中，诊断率为91%（31例活检中有28例），临床效用为58%（31例活检中有18例）。随着时间推移临床效用的下降具有统计学意义（p = 0.01）。怀疑转移的诊断率为100%（11/11），临床效用为91%（10/11）。怀疑原发性肿瘤的诊断率和临床效用分别为93%（42例中有39例）和67%（42例中有28例）。临床效用的这种差异具有统计学意义（p = 0.02）。CT引导下软组织活检的诊断率为75%（16例活检中有12例），临床效用为69%（16例活检中有11例）。软组织活检的诊断率显著低于骨活检（p = 0.01）。诊断性活检率与评估病理学家或体内病变位置之间没有关系。
CT引导下活检在肌肉骨骼病变的诊断中有用，然而，由于大量诊断性活检未能指导治疗，其临床效用显著低于其诊断准确性和诊断率，特别是在怀疑原发性病变时。在我们的研究中，基于术前怀疑转移的临床效用差异比以前显示的更大。与怀疑原发性骨病变和软组织病变的活检相比，CT引导下经皮针吸活检在怀疑骨转移的情况下更有可能指导治疗。
