CT of the urinary tract revisited

A CT-based deep learning model predicts overall survival in patients with muscle invasive bladder cancer after radical cystectomy: a multicenter retrospective cohort study

BACKGROUND

Muscle invasive bladder cancer (MIBC) has a poor prognosis even after radical cystectomy (RC). Postoperative survival stratification based on radiomics and deep learning (DL) algorithms may be useful for treatment decision-making and follow-up management. This study was aimed to develop and validate a DL model based on preoperative computed tomography (CT) for predicting postcystectomy overall survival (OS) in patients with MIBC.

METHODS

MIBC patients who underwent RC were retrospectively included from four centers, and divided into the training, internal validation, and external validation sets. A DL model incorporated the convolutional block attention module (CBAM) was built for predicting OS using preoperative CT images. The authors assessed the prognostic accuracy of the DL model and compared it with classic handcrafted radiomics model and clinical model. Then, a deep learning radiomics nomogram (DLRN) was developed by combining clinicopathological factors, radiomics score (Rad-score) and deep learning score (DL-score). Model performance was assessed by C-index, KM curve, and time-dependent ROC curve.

RESULTS

A total of 405 patients with MIBC were included in this study. The DL-score achieved a much higher C-index than Rad-score and clinical model (0.690 vs. 0.652 vs. 0.618 in the internal validation set, and 0.658 vs. 0.601 vs. 0.610 in the external validation set). After adjusting for clinicopathologic variables, the DL-score was identified as a significantly independent risk factor for OS by the multivariate Cox regression analysis in all sets (all P <0.01). The DLRN further improved the performance, with a C-index of 0.713 (95% CI: 0.627-0.798) in the internal validation set and 0.685 (95% CI: 0.586-0.765) in external validation set, respectively.

CONCLUSIONS

A DL model based on preoperative CT can predict survival outcome of patients with MIBC, which may help in risk stratification and guide treatment decision-making and follow-up management.

Atypical presentations of UTUC: a case report of three patients

Background

Upper tract urothelial carcinoma (UTUC) is a rare clinical condition primarily characterized by symptoms such as gross or microscopic hematuria, flank pain, and renal colic. Although computed tomography urography (CTU) is currently the most accurate imaging modality for diagnosis, atypical presentations and physical examination findings can sometimes obscure lesions, posing diagnostic challenges.

Case presentation

In this report, three patients exhibited atypical symptoms, sharing a common complaint of flank pain. Notably, the first patient, who had recently undergone laparoscopic right duplex nephrectomy, presented with microscopic hematuria, whereas the other two did not show any gross or microscopic hematuria. Computed tomography urography revealed hydronephrosis and infection without significant renal pelvic space-occupying lesions, with persistently elevated white blood cell (WBC) counts, but no fever. These atypical clinical presentations confounded clinicians, delaying the diagnosis of upper tract urothelial carcinoma until postoperative pathological examination for the first two patients and resulting in advanced-stage diagnosis for the third patient. Postoperative pathology confirmed high-grade invasive upper tract urothelial carcinoma in all three patients.

Conclusion

Upper tract urothelial carcinoma can manifest atypically without hematuria and may be challenging to visualize on computed tomography urography, potentially leading to misdiagnosis. Therefore, clinicians should maintain a high level of suspicion for malignant tumors when patients exhibit hydronephrosis, infection on imaging, and persistently elevated white blood cell counts without fever, even in the absence of typical signs of upper urothelial carcinoma on computed tomography urography.

How to estimate stone volume and its use in stone surgery: a comprehensive review

OBJECTIVE

Current interventional guidelines refer to the cumulative stone diameter to choose the appropriate surgical modality (ureteroscopy [URS], extracorporeal shockwave lithotripsy [ESWL] and percutaneous nephrolithotomy [PCNL]). The stone volume (SV) has been introduced recently, to better estimate the stone burden. This review aimed to summarize the available methods to evaluate the SV and its use in urolithiasis treatment.

MATERIAL AND METHODS

A comprehensive review of the literature was performed in December 2022 by searching Embase, Cochrane and Pubmed databases. Articles were considered eligible if they described SV measurement or the stone free rate after different treatment modalities (SWL, URS, PCNL) or spontaneous passage, based on SV measurement. Two reviewers independently assessed the eligibility and the quality of the articles and performed the data extraction.

RESULTS

In total, 28 studies were included. All studies used different measurement techniques for stone volume. The automated volume measurement appeared to be more precise than the calculated volume. In vitro studies showed that the automated volume measurement was closer to actual stone volume, with a lower inter-observer variability. Regarding URS, stone volume was found to be more predictive of stone free rates as compared to maximum stone diameter or cumulative diameter for stones >20 mm. This was not the case for PCNL and SWL.

CONCLUSIONS

Stone volume estimation is feasible, manually or automatically and is likely a better representation of the actual stone burden. While for larger stones treated by retrograde intrarenal surgery, stone volume appears to be a better predictor of SFR, the superiority of stone volume throughout all stone burdens and for all stone treatments, remains to be proven. Automated volume acquisition is more precise and reproducible than calculated volume.