(2022) 22:163 Yin et al BMC Cancer https://doi.org/10.1186/s12885-022-09239-3 Open Access RESEARCH Diagnostic performance of MRI, SPECT, and PET in detecting renal cell carcinoma: a systematic review and meta-analysis Qihua Yin1, Huiting Xu1, Yanqi Zhong2, Jianming Ni1,3* and Shudong Hu2* Abstract Background: Renal cell carcinoma (RCC) is one of the most common malignancies worldwide Noninvasive imaging techniques, such as magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), and positron emission tomography (PET), have been involved in increasing evolution to detect RCC This meta-analysis aims to compare to compare the performance of MRI, SPECT, and PET in the detection of RCC in humans, and to provide evidence for decision-making in terms of further research and clinical settings Methods: Electronic databases including PubMed, Web of Science, Embase, and Cochrane Library were systemically searched The keywords such as “magnetic resonance imaging”, “MRI”, “single-photon emission computed tomography”, “SPECT”, “positron emission tomography”, “PET”, “renal cell carcinoma” were used for the search Studies concerning MRI, SPECT, and PET for the detection of RCC were included Pooled sensitivity, specificity, and the area under the summary receiver operating characteristic (SROC) curve (AUC), etc were calculated Results: A total of 44 articles were finally detected for inclusion in this study The pooled sensitivities of MRI, 18F-FDG PET and 18F-FDG PET/CT were 0.80, 0.83, and 0.89, respectively Their respective overall specificities were 0.90, 0.86, and 0.88 The pooled sensitivity and specificity of MRI studies at 1.5 T were 0.86 and 0.94, respectively With respect to prospective PET studies, the pooled sensitivity, specificity and AUC were 0.90, 0.93 and 0.97, respectively In the detection of primary RCC, PET studies manifested a pooled sensitivity, specificity, and AUC of 0.77, 0.80, and 0.84, respectively The pooled sensitivity, specificity, and AUC of PET/CT studies in detecting primary RCC were 0.80, 0.85, and 0.89 Conclusion: Our study manifests that MRI and PET/CT present better diagnostic value for the detection of RCC in comparison with PET MRI is superior in the diagnosis of primary RCC Keywords: MRI, SPECT, PET, Renal cell carcinoma, Diagnostic performance, Meta-analysis Introduction Renal cancer is one of the most frequently diagnosed cancers worldwide, which ranks the 6th most frequently confirmed malignant tumor in men and the 8th *Correspondence: nijianming@njmu.edu.cn; hsd2001054@163.com Department of Radiology, Affiliated Hospital of Jiangnan University, No 1000, Hefeng Road, Wuxi 214122, China Shanghai Key Laboratory of Molecular Imaging, Shanghai University of Medicine and Health Sciences, Shanghai 201318, China Full list of author information is available at the end of the article in women [1] 90% of all renal malignant tumors tend to be renal cell carcinoma (RCC) on a histopathological basis [2, 3] There are three major histological subtypes of renal cell carcinoma: clear cell RCC, papillary RCC, and chromophobe RCC [4] It is manifested that over one-half of patients with renal cell carcinoma are asymptomatic [5] Approximately 33 to 50% of suspected patients are diagnosed with metastatic diseases at the time of initial detection, furthermore, 20 to 40% of patients with confirmed RCC progress to metastatic © The Author(s) 2022 Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ The Creative Commons Public Domain Dedication waiver (http://creativeco mmons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated in a credit line to the data Yin et al BMC Cancer (2022) 22:163 diseases even after surgical resection [6, 7] Consequently, timely and accurate detection of the early stage and advanced stage of the disease is of great significance Partial or radical nephrectomy is still the gold standard for the treatment of renal tumors, no significant benefit have been proved regarding RCC adjuvant therapies [5] Biopsy diagnosis is still the gold standard for confirmation of RCC although it is an invasive modality that may result in unnecessary adverse outcomes [8] Various noninvasive imaging approaches are commonly employed in the detection of RCC [9] For decades, ultrasound (US) has been used as one of the first-line modalities for diagnostic imaging of patients with renal lesions due to its cost-effective nature, however, the efficacy of US is not satisfactory especially in patients with suspected malignancies [9] Although computed tomography (CT) has been utilized as the confirmative standard for RCC imaging for decades, it manifested poor performance in differentiation among solid masses, fat-poor angiomyolipoma (AML), and oncocytoma [10, 11] Compared to CT, magnetic resonance imaging (MRI) plays an increasingly important role in the diagnosis and restaging of RCC, particularly in patients with unclear results, allergic reactions, pregnancies, as it has no ionizing radiation exposure and superior soft tissue resolution [12, 13] Although contrast-enhanced MRI performed better than diffusionweighted (DW) MRI for the diagnosis of RCC, patients who have renal dysfunction are at risk for nephrogenic systemic fibrosis or contrast material–induced nephropathy [14] In recent years, targeted imaging approaches have made great progression in the diagnosis of RCC Single photon emission computed tomography-computed tomography (SPECT) imaging is used to differentiate RCC and detect metastases in renal cancer [15, 16] Furthermore, positron emission tomography (PET) imaging utilizing 18F-fluoro-deoxy-glucose (FDG) and other tracers (124I-girentuximab, 68Ga-DOTATOC, 11 C-acetate, 18F-fluoride) has been studied as diagnostic biomarkers in RCC [17–22] Especially, PET plays an important role in the detection of recurrent or metastatic RCC [22, 23] Furthermore, specific European Association of Nuclear Medicine (EANM) procedure guidelines have been intended to assist practitioners in performing, interpreting and reporting the results of FDG PET/CT for imaging of patients [24] A large number of studies have assessed the diagnostic performance of non-invasive approaches in terms of RCC, nevertheless, the results are heterogeneous [15, 18, 22, 23, 25–27] This study aimed to generate a more comprehensive comparison of the diagnostic performance of MRI, SPECT, and PET in the detection of RCC by conducting a meta-analysis, and subsequently to guide the Page of 13 diagnosis and differentiation of RCC in the field of scientific research and clinical application Materials and methods The entire process of this study was conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) [28] Search strategy and selection criteria The electronic databases of PubMed, Web of Science, Embase, and Cochrane Library were comprehensively searched with a publication date from inception to January 31, 2021 Articles in the English language were considered The following key terms were used for the database research: “magnetic resonance imaging”, “MRI”, “single-photon emission computed tomography”, “SPECT”, “positron emission tomography”, “PET”, “renal cell carcinoma” Besides, we manually screened the references of the articles included for more potentially eligible studies The inclusion criteria of studies were as follows: 1) MRI, SPECT, and/or PET were used for the detection of RCC in patients with suspected or confirmed RCC; 2) a reference standard was utilized to assess diagnostic performance; 3) absolute numbers of patients with true positive (TP), false positive (FP), true negative (TN) and false negative (FN) results can be retrieved in the published articles or recalculated based on other parameters (accuracy rate, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), number of all participants) presented in the manuscripts In case that the studies were undertaken by the same research group, those with the largest sample size or the most complete information were included to avoid duplicates Articles were excluded if they were case reports, reviews, letters, news, conference abstracts, animal studies, or studies with insufficient data Two independent investigators (QY and HX) conducted the process of literature search and study inclusion Discrepancies were resolved by discussion If no consensus was reached, a third author (JN) was involved Data extraction and quality assessments Two researchers (QY and YZ) independently performed the title and abstract screening according to the inclusion criteria A full-text reading of the literature was conducted for the final inclusion The following information was extracted from each study: first author’s name, year of publication, study design, type of RCC (primary or recurrent/metastatic), number of patients analyzed, percentage of the male, age of the participants, reference standard, imaging modality and type of radiotracers used in the study, absolute numbers of patients with TP, TN, FP, and FN numbers Yin et al BMC Cancer (2022) 22:163 To evaluate the methodological quality of the enrolled studies, we used the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) tool This method contains four main components in terms of participant selection, index test, reference standard, as well as flow and timing, all the components are assessed in terms of risk of bias, and the first three components are also evaluated the concerns of applicability [29] Statistical analysis We calculated pooled sensitivity, specificity, positive likelihood ratio (PLR), negative likelihood ratio (NLR), diagnostic odds ratio (DOR), and the 95% confidence intervals (CIs) and the area under the summary receiver operating characteristic (SROC) curve (AUC) Fig. 1 Search results and flow chart of the meta-analysis Page of 13 A Cochran Q value and the I2 statistic were used to detect the heterogeneity of studies included I2 statistics in the range of 0–25%, 25–50%, 50–75%, and 75–100% were considered to be of insignificant, low, moderate, and high heterogeneity between studies, respectively [30] Meta-regression was performed to investigate the possible source of heterogeneity between the included studies A Deeks’ method was introduced to statistically test the asymmetry of the funnel plot and detect publication bias We conducted sensitivity analysis to evaluate the impacts of one single study on the overall outcomes All statistical analyses were processed on the study basis using the Stata 15.0 software and Review Manager 5.3 software A p value