Diagnostic Yield and Complication Rate in Percutaneous Needle Biopsy of Renal Hilar Masses With Comparison With Renal Cortical Mass Biopsies in a Cohort of 195 Patients

Deep learning algorithm (YOLOv7) for automated renal mass detection on contrast-enhanced MRI: a 2D and 2.5D evaluation of results

INTRODUCTION

Accurate diagnosis and treatment of kidney tumors greatly benefit from automated solutions for detection and classification on MRI. In this study, we explore the application of a deep learning algorithm, YOLOv7, for detecting kidney tumors on contrast-enhanced MRI.

MATERIAL AND METHODS

We assessed the performance of YOLOv7 tumor detection on excretory phase MRIs in a large institutional cohort of patients with RCC. Tumors were segmented on MRI using ITK-SNAP and converted to bounding boxes. The cohort was randomly divided into ten benchmarks for training and testing the YOLOv7 algorithm. The model was evaluated using both 2-dimensional and a novel in-house developed 2.5-dimensional approach. Performance measures included F1, Positive Predictive Value (PPV), Sensitivity, F1 curve, PPV-Sensitivity curve, Intersection over Union (IoU), and mean average PPV (mAP).

RESULTS

A total of 326 patients with 1034 tumors with 7 different pathologies were analyzed across ten benchmarks. The average 2D evaluation results were as follows: Positive Predictive Value (PPV) of 0.69 ± 0.05, sensitivity of 0.39 ± 0.02, and F1 score of 0.43 ± 0.03. For the 2.5D evaluation, the average results included a PPV of 0.72 ± 0.06, sensitivity of 0.61 ± 0.06, and F1 score of 0.66 ± 0.04. The best model performance demonstrated a 2.5D PPV of 0.75, sensitivity of 0.69, and F1 score of 0.72.

CONCLUSION

Using computer vision for tumor identification is a cutting-edge and rapidly expanding subject. In this work, we showed that YOLOv7 can be utilized in the detection of kidney cancers.

The Role of 99mTc-Sestamibi Single-photon Emission Computed Tomography/Computed Tomography in the Diagnostic Pathway for Renal Masses: A Systematic Review and Meta-analysis

CONTEXT

The diagnostic accuracy of current imaging techniques in differentiating benign from malignant neoplasms in the case of indeterminate renal masses is still suboptimal.

OBJECTIVE

To evaluate the diagnostic accuracy of 99mTc-sestamibi (SestaMIBI) single-photon emission tomography computed tomography (SPECT)/CT in characterizing indeterminate renal masses by differentiating renal oncocytoma and hybrid oncocytic/chromophobe tumor (HOCT) from (1) all other renal lesions and (2) all malignant renal lesions. Secondary outcomes were: (1) benign versus malignant; (2) renal oncocytoma and HOCT versus clear cell (ccRCC) and papillary (pRCC) renal cell carcinoma; and (3) renal oncocytoma and HOCT versus chromophobe renal cell carcinoma (chRCC).

EVIDENCE ACQUISITION

A literature search was conducted up to November 2022 using the PubMed/MEDLINE, Embase, and Web of Science databases. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to identify eligible studies. Studies included were prospective and retrospective cross-sectional studies in which SestaMIBI SPECT/CT findings were compared to histology after renal mass biopsy or surgery.

EVIDENCE SYNTHESIS

Overall, eight studies involving 489 patients with 501 renal masses met our inclusion criteria. The sensitivity and specificity of SestaMIBI SPECT/CT for renal oncocytoma and HOCT versus all other renal lesions were 89% (95% confidence interval [CI] 70-97%) and 89% (95% CI 86-92%), respectively. Notably, for renal oncocytoma and HOCT versus ccRCC and pRCC, SestaMIBI SPECT/CT showed specificity of 98% (95% CI 91-100%) and similar sensitivity. Owing to the relatively high risk of bias and the presence of heterogeneity among the studies included, the level of evidence is still low.

CONCLUSIONS

SestaMIBI SPECT/CT has good sensitivity and specificity in differentiating renal oncocytoma and HOCT from all other renal lesions, and in particular from those with more aggressive oncological behavior. Although these results are promising, further studies are needed to support the use of SestaMIBI SPECT/CT outside research trials.

PATIENT SUMMARY

A scan method called SestaMIBI SPECT/CT has promise for diagnosing whether kidney tumors are malignant or not. However, it should still be limited to research trials because the level of evidence from our review is low.

Diagnostic accuracy of percutaneous core biopsy before cryoablation for small-sized renal cell carcinoma

PURPOSE

To retrospectively determine the diagnostic accuracy of a percutaneous core biopsy performed before cryoablation for small-sized renal cell carcinoma.

METHODS

In this study, 216 patients underwent a percutaneous core biopsy for 242 renal lesions suspected to be renal cell carcinoma on image findings before cryoablation at Kyushu University Hospital. We calculated the success rate of the histological diagnosis and investigated factors that may have contributed to the diagnostic success. Complications caused by the biopsy procedure were also evaluated.

RESULTS

The histological diagnosis was successful in 203 lesions (82.8%). The success rate of the histological diagnosis was 65.4% (34/52 cases) for tumors with a diameter of ≤15 mm and 88.9% (169/190 cases) for those >15 mm. Therefore, tumor diameter was a factor contributing to the histological diagnosis success rate in both univariate and multivariable analyses (P < 0.001). For lesions with a tumor diameter ≤15 mm, the histological diagnosis success rates increased from 50.0% to 76.2% in the presence of pre-lipiodol marking and to 85.7% when the biopsy procedure was performed separately from cryoablation; the latter was statistically significant (P = 0.039). Major complications that may have been caused by the biopsy procedure were grade 3 bleeding and tract seeding (one case each).

CONCLUSION

Percutaneous core biopsy in cryoablation for small-sized renal cell carcinoma had a high diagnostic rate and was safely performed. For lesions with a tumor diameter ≤15 mm, a separate biopsy procedure and pre-lipiodol marking may improve the diagnostic accuracy.

Complications After Renal Mass Biopsy: Frequency, Nature, Timing, and Associated Characteristics

BACKGROUND. Observation periods after renal mass biopsy (RMB) range from 1 hour to overnight hospitalization. Short observation may improve efficiency by allowing use of the same recovery bed and other resources for RMBs in additional patients. OBJECTIVE. The purpose of this study was to evaluate the frequency, timing, and nature of complications after RMB, as well as to identify characteristics associated with such complications. METHODS. This retrospective study included 576 patients (mean age, 64.9 years; 345 men, 231 women) who underwent percutaneous ultrasound- or CT-guided RMB at one of three hospitals, performed by 22 radiologists, between January 1, 2008, and June 1, 2020. The EHR was reviewed to identify postbiopsy complications, which were classified as bleeding-related or non-bleeding-related and as acute (< 24 hours), subacute (24 hours to 30 days), or delayed (> 30 days). Deviations from normal clinical management (analgesia, unplanned laboratory testing, or additional imaging) were identified. RESULTS. Acute and subacute complications occurred after 3.6% (21/576) and 0.7% (4/576) of RMBs, respectively. No delayed complication or patient death occurred. A total of 76.2% (16/21) of acute complications were bleeding-related. A deviation from normal clinical management occurred after 1.6% (9/551) of RMBs that had no associated postbiopsy complication. Among the 16 patients with bleeding-related acute complications, all experienced a deviation, with mean time to deviation of 56 ± 47 (SD) minutes (range, 10-162 minutes; ≤ 120 minutes in 13/16 patients). The five non-bleeding-related acute complications all presented at the time of RMB completion. The four subacute complications occurred from 28 hours to 18 days after RMB. Patients with, versus those without, a bleeding-related complication had a lower platelet count (mean, 197.7 vs 250.4 × 109/L, p = .01) and greater frequency of entirely endophytic renal masses (47.4% vs 19.6%, p = .01). CONCLUSION. Complications after RMB were uncommon and presented either within 3 hours after biopsy or more than 24 hours after biopsy. CLINICAL IMPACT. A 3-hour monitoring window after RMB before patient discharge (in the absence of deviation from normal clinical management and complemented by informing patients of the low risk of a subacute complication) may provide both safe patient management and appropriate resource utilization.

Multidisciplinary Approach and Outcomes of Pretreatment Small (cT1a) Renal Mass Biopsy: Single-Center Experience

PURPOSE

We evaluated our experience of a multidisciplinary approach to renal mass biopsy (RMB) for small renal masses (SRM) employing in-office ultrasound (US) guided biopsy by urology (24%), computed tomography (CT) or US biopsy by interventional radiology (IR) (79%), and endoscopic ultrasound-guided biopsy by gastroenterology (GI) (4%).

METHODS

A single-institution retrospective review of patients who underwent RMB for SRM from May 2013 to August 2019 was conducted. Data regarding patient demographics, tumor characteristics, biopsy technique, histopathology, and management were collected. Diagnostic rates, concordance with final pathology, complications, and outcomes were analyzed.

RESULTS

Of the 192 biopsies reviewed, 63% biopsies were malignant, 20% were benign, and 17% were non-diagnostic. Based on biopsy results, 71 patients (37%) elected active surveillance. Thirty-eight (20%) patients underwent cryoablation, 56 (29%) underwent partial nephrectomy (PN), 14 (7%) underwent radical nephrectomy (RN) and the remaining patients were treated elsewhere. The rate of surgery for benign pathology after pretreatment RMB was 3%. The concordance rate between biopsy and final pathology was 99% for malignancy, 96% for specific pathology subtype, and 85% for RCC grade. Median time from diagnosis to definitive treatment was 97 days (urology: 76, IR: 110 and GI: 54, p=0.002). Three (1.6%) Clavien I complications were reported.

CONCLUSION

Our multidisciplinary approach to renal mass biopsy for clinical stage T1a demonstrated favorable safety and diagnostic rates, which effectively directed management strategies and minimized surgery for benign disease. Urologist performed office-biopsies significantly shortened the time from diagnosis to definitive treatment. Our experience with GI EUS biopsy has demonstrated feasibility and safety for tumors that were otherwise not accessible percutaneously.

Diagnostic performance of prospectively assigned clear cell Likelihood scores (ccLS) in small renal masses at multiparametric magnetic resonance imaging

INTRODUCTION

Detection of small renal masses (SRM) is increasing with the use of cross-sectional imaging, although many incidental lesions have negligible metastatic potential. A method to identify this subtype would aid in risk stratification. A previously reported clear cell likelihood score (ccLS; 1-very unlikely, 2-unlikely, 3-equivocal, 4-likely, and 5-very likely), based on retrospective review of multiparametric magnetic resonance imaging (mpMRI), predicted the likelihood of encountering clear cell renal cell carcinoma (ccRCC) at surgery. Here, we assess the performance of ccLS prospectively assigned for prediction of ccRCC.

METHODS

Patients with a known renal mass who underwent mpMRI at a single institution between June 2016 and April 2018 were prospectively assigned a ccLS as part of the clinical MRI report. These patients were retrospectively reviewed, and those with a cT1a lesion and available pathological tissue diagnosis (diagnostic biopsy or extirpative surgery) were selected for analysis.

RESULTS

In total, 57 patients (mean age 61.7 ± 14.9 years) with 63 cT1a renal masses were identified. Mean tumor size was 2.7 ± 0.7 cm. Defining ccLS 4-5 lesions as positive demonstrated an overall accuracy of 84%, sensitivity of 89%, specificity of 79%, positive predictive value of 84%, and negative predictive value of 86%. A ccLS of 1-2 demonstrates an 86% accuracy and 100% sensitivity/positive predictive value of identifying non-ccRCC histology.

CONCLUSIONS

Utilizing prospectively assigned ccLS, we confirm that mpMRI can reasonably identify ccRCC histology in cT1a renal masses. Standardization of imaging protocols and reporting criteria such as the ccLS can be used to aid in the diagnosis and management of small renal masses.

Role of Virtual Biopsy in the Management of Renal Masses

OBJECTIVE. Renal masses comprise a heterogeneous group of pathologic conditions, including benign and indolent diseases and aggressive malignancies, complicating management. In this article, we explore the emerging role of imaging to provide a comprehensive noninvasive characterization of a renal mass-so-called "virtual biopsy"-and its potential use in the management of patients with renal tumors. CONCLUSION. Percutaneous renal mass biopsy (RMB) remains a valuable method to provide a presurgical histopathologic diagnosis of renal masses, but it is an invasive procedure and is not always feasible. Accumulating data support the use of imaging features to predict histopathology of renal masses. Imaging may help address some of the inherent limitations of RMB, and in certain settings, a multimodal clinical approach may allow decreasing the need for RMB.