The role of 64-Slides computed tomography scan in preoperative diagnosis of retroperitoneal laparoscopic surgery for patients with ureteropelvic junction obstruction at Viet Duc hospital

Journal of military pharmaco-medicine n 0 1-2020 212 THE ROLE OF 64-SLIDES COMPUTED TOMOGRAPHY SCAN IN PREOPERATIVE DIAGNOSIS OF RETROPERITONEAL LAPAROSCOPIC SURGERY FOR PATIENTS WITH URETEROPELVIC JUNCTION OBSTRUCTION AT VIET DUC HOSPITAL Nguyen Duc Minh1; Hoang Long1; Vu Nguyen Khai Ca1 SUMMARY Objectives: To determine the sensitivity and specificity of multidisciplinary computed tomography in the diagnosis of ureteropelvic junction obstruction among patients undergoing retroperitoneal laparoscopic surgery at Viet Duc Hospital from 2012 to 2017. Subjects and methods: A prospective descriptive study on 62 patients diagnosed with ureteropelvic junction obstruction at Viet Duc Hospital. Cohen's Kappa coefficient was used to evaluate the agreement between CT-scanner and in-surgery assessment. Sensitivity and specificity were also calculated to determine the reliability of 64-slides CT-scanner in diagnosing of damage of urinary system among patients with ureteropelvic junction obstruction. Results: Comparison between 64-slides CT-scanner imaging and evaluation anatomy during surgery, we found a high agreement of renal pelvis diameter between 64-slides CT-scanner imaging and in-surgery assessment (96.78%) and Cohen Kappa’s score was 0.9338 (p < 0.001). The sensitivity and specificity were 97.2% and 96.2%, respectively. The agreement in diagnosing abnormality of renal artery was also high (91.94%) and Cohen Kappa’s score was 0.8079 (p < 0.001). The sensitivity and specificity were found at 80% and 97.62%, respectively. CT-scanner was also found to have high sensitivity and specificity in diagnosing the position of ureters coming from renal pelvis and angle of renal pelvis and ureter (> 80%). Conclusions: The 64-slides CT-scanner showed high sensitivity and specificity in diagnosing the damage of urinary system among patients with ureteropelvic junction obstruction who underwent retroperitoneal laparoscopic surgery at Viet Duc Hospital from 2012 to 2017. * Keywords: Ureteropelvic junction obstruction; CT-scanner; Sensitivity; Specificity. INTRODUCTION Computed tomography (CT) imaging procedure, especially 64-slides CT-scans plays an important role in urological examination techniques. The layers of body-axis slices from the kidney to the prostate gland can reconstruct images in any plane or reconstruct 3-dimensional images, allowing examination of parenchyma, exit lines, renal pelvis, ureter administration, bladder and prostate [1]. CT could also be able to distinguish blood, fat, calcification, necrosis, fluid, etc. In addition, CT with intravenous contrast injection also helps to determine more distinct structures, such as vascular lesions, poor vascularity, avascularity .and .renal .blood .vessels. 1. Viet Duc Hospital Corresponding author: Nguyen Duc Minh (hienminh28bvvd@gmail.com) Date received: 16/12/2019 Date accepted: 30/12/2019 Journal of military pharmaco-medicine n 0 1-2020 213 CT 64-slides could render the renal blood vessels, which is very valuable in the treatment and prognosis of the kidney disease. Moreover, the greatest benefit of CT 64-slides is that it takes shorter shooting time, produces better images and has less noise than conventional CT [2]. In the patients with ureteropelvic junction obstruction (UPJO), multidisciplinary CT-scan with angiography and vascular system rendering is considered as gold-standard for diagnosing urological pathologies. Currently, CT-scans are more commonly used as diagnostic imaging tools to diagnose UJPO rather than UIV [3, 4]. CT-scans could provide detailed information about the anatomy and function of pathological kidneys, clearly identify the location and severity of stalemate of the junction and the condition of the lower ureter. In addition, CT-scan also helps to diagnose the comorbidities of patients, such as poorly contrasted stones or polyps. According to Rabat et al, CT-scan helped to diagnose variants of renal vascular blood vessels with the sensitivity from 85 to 100%, and detect abnormal blood vessels at the junction with an accuracy of 83.3% [1]. The information provided from multidisciplinary CT-scan is very important in the preoperative diagnosis because it helps the surgeon to decide the most appropriate treatment method, access path and imaging techniques for each specific case. Vietnam has applied CT 64-slides scan in supporting for diagnosis and treatment of several diseases in both internal medicine and surgery filed. However, research evidences of role of CT-scan 64-slides among patients with UPJO still limited across the country. This study aims: To determine the sensitivity and specificity of multidisciplinary CT in the diagnosis of UPJO among patients who underwent retroperitoneal laparoscopic surgery at Viet Duc Hospital from 2012 to 2017. SUBJECTS AND METHODS 1. Subjects. Study participants were patients diagnosed with UJPO and undergoing peritoneal laparoscopic surgery at Urology Surgery Department, Viet Duc Hospital from 2012 to 2017. * Inclusion criteria: - Adults with age ≥ 16. - Having 64-slides CT-scanner’s urologic imaging results before surgery. - Having pre- and in-operative assessment. * Exclusion criteria: - Postoperative diagnosis was not UJPO. - Acquired UJPO after surgery. - Patients with chronic comorbidities that may affect the surgery outcomes, such as: heart failure, coronary artery disease, liver failure, kidney failure, ankylosing spondylitis, etc. 2. Methods. * Study design: We conducted a prospective study with pre- and post-assessment before and after surgery. * Sample size: A convenience sampling method has been applied with all patients who met the inclusion criteria were selected to participate. A total of 62 patients were enrolled to the study from 2012 to 2017. Journal of military pharmaco-medicine n 0 1-2020 214 * Study measurement: - Demographic characteristics: We collected data about age, gender and employment status among participants at the time of enrollment. - Pre-surgical assessment: Clinical manifestations, ultrasound and 64-slides CT imaging were assessed at the baseline to analyze the current status of urinary system related to UJPO, included renal pelvis diameter, the angle of renal pelvis and ureter, the position of ureters coming from renal pelvis and the abnormality of renal artery. - In-surgery assessment: We assessed the damage of urinary system by macroscopic and microscopic anatomy with the similar indicators as mentioned above in pre-surgery assessment. - Post-surgery assessment: Clinical progression of patients was assessed after surgery, including patient's condition, drainage, amount and nature of the urine. Post-operative’s complications were also collected. * Statistical analysis: Epi Data was used for data entry and cleaning. All statistical analysis was made by using STATA 14.0. Descriptive analysis was used to describe the demographic, clinical and imaging characteristics with median and IQR for quantitative variables and frequency and percentage for qualitative variables. We compared the renal pelvis diameter, the angle of renal pelvis and ureter, the position of ureters from renal pelvis and the abnormality of renal artery between image results obtained 64-slides CT-scanner and actual assessment results in surgery. Cohen's Kappa coefficient was used to evaluate the agreement between CT-scanner and in-surgery assessment. Sensitivity and specificity were also calculated to determine the reliability of 64-slides CT-scanner in diagnosing damage of urinary system among patients with UJPO. * Ethical issues: The research proposal was approved by the review board of the Vietnam Military Medical University. The study was accepted by Viet Duc Hospital and Vietnam Military Medical University. The information in the research is completely confidential and is used only for research purposes. RESULTS Table 1: 64-slides CT-scanner imaging results before surgery. 64-slides CT-scanner Frequency (n = 62) Percentage (%) The position of ureters from renal pelvis Normal 47 75.8 High 15 24.2 The angle of renal pelvis and ureter Sharp 14 22.6 Obtuse 48 77.4 The abnormality of renal artery None 42 67.7 Yes 20 32.3 62 patients underwent CT imaging before surgery, 24.2% had high angle of renal pelvis and ureter. The proportion of patients with sharp position of ureters from renal pelvis was 22.6%. The abnormality of renal artery was found in 32.3% of participants. Journal of military pharmaco-medicine n 0 1-2020 215 Table 2: Comparison of renal pelvis diameter between CT-scanner imaging and in surgery assessment. In-surgery assessment 64-slides CT imaging < 35 mm ≥ 35 mm Total < 35 mm 35 1 36 ≥ 35 mm 1 25 26 Total 36 26 62 Agreement 96.78% Expected agreement 51.3% Cohen Kappa’s score 0.9338 p-value < 0,001 Sensitivity 97.22% Specificity 96.2% High agreement of renal pelvis diameter between 64-slides CT-scanner imaging and in surgery assessment with the agreement ratio was 96.78% and Cohen Kappa’s score was 0.9338 (p < 0.001). The sensitivity and specificity were 97.22% and 96.2%, respectively. Table 3: Comparison of the position of ureters coming from renal pelvis between CT-scanner imaging and on surgery assessment. In-surgery assessment 64-slides CT imaging Normal High Total Normal 46 2 48 High 2 12 14 Total 48 14 62 Agreement 93.54% Expected agreement 65.1% Cohen Kappa’s score 0.8155 p-value < 0.001 Sensitivity 85.71% Specificity 95.83% We found high agreement of the position of ureters coming from renal pelvis between 64-slides CT-scanner imaging and in-surgery assessment. The agreement ratio was very high (93.54%) and Cohen Kappa’s score was 0.8155 (p < 0.001). The sensitivity and specificity were also high (85.71% and 95.83%). Table 4: Comparison of the abnormality of renal artery between CT-scanner imaging and in-surgery assessment. In-surgery assessment 64-slides CT imaging None Yes Total None 41 1 42 Yes 4 16 20 Total 45 17 62 Agreement 91.94% Expected agreement 58.01% Cohen Kappa’s score 0.8079 p-value < 0.001 Sensitivity 80% Specificity 97.62% High agreement of abnormality of renal artery was found between 64-slides CT-scanner imaging and in-surgery assessment. The agreement ratio was 91.94% and Cohen Kappa’s score was 0.8079 (p < 0.001). The sensitivity and specificity were 80% and 97.62%. Journal of military pharmaco-medicine n 0 1-2020 216 DISCUSSION The selection of treatment procedure for UJPO depends on many factors, including the renal function, the degree of renal hydronephrosis and the length of the stenosis segment [1]. Previously, radiography of the urinary system with intravenous contrast injection (UIV) was widely used in the diagnosis of urological diseases including UJPO [2]. However, this method has many disadvantages, such as high errors rate, patients may feel uncomfortable and the image is not sufficiently detailed for supporting the diagnosis. This study was one of the first researches to assess the role of CT-scanner in diagnosing patients with UJPO, as well as, calculate sensitivity and specificity of CT-scanner in pre-surgery assessment, compared with the macroscopic and microscopic anatomy during surgery [5, 6]. The image resolution density of CT is much higher than conventional X-rays, moreover, the enhanced contrast can cross patients' areas of infection. In addition, the urinary tract could also be clear displayed in CT images. Results by Kawamoto et al showed that CT not only displayed obstruction ureter, but also the location and the root of obstruction [7]. El-Nahas et al also reported similar results that the obstruction of the ureteropelvic that cannot be showed in the X-ray of intravenous urinary system, could be seen in CT-scanner in a group of 42 patients with UJPO [8]. In study by Chong Xie et al, the proportion of the visible of the obstruction on CT-scan images was 90.2%, much higher than the X-rays technique (39.3%). Except for patients with completely obstructed, CT-scanner may show most of the urinary tract and the obstruction of renal pelvis [9]. For patients with tumors or kidney stones, CT-scanner could not only show the urinary tract and fill the defect of the tumor, but also reflected the position and overall morphological characteristics of the tumor, as well as the condition of surrounding tissue. Consequently, indirect diagnostic guesses can be avoided by using CT-scanner and removed the limitations in the X-ray urinary tract systems. A further advantage of CT-scanner in the diagnosis of UJPO is that the integrity, morphology and perfusion of renal parenchyma can be assessed in addition to obtaining information about the spatial orientation and presence of the disease. Many studies had suggested that CT-scanner should be considered as a routine imaging technique in the diagnosis and treatment of renal pelvic junction obstruction [8]. The sensitivity of CT-scanner in detecting the root cause of the obstruction was determined to be 100%, much higher than X-ray (74%) in group of patients with chronic obstructive urological disease [10]. In our study, comparing the evaluation of CT with the assessment during surgery, the sensitivity and specificity of 64-slides CT-scanner were above 85%, showing a high value in pre-surgical diagnosis among patients with UJPO. In the assessment of renal pelvis diameter, the agreement between CT-scanner imaging and the macroscopic and microscopic anatomy Journal of military pharmaco-medicine n 0 1-2020 217 during surgery was nearly 90%, and the sensitivity and specificity were high at 97.2% and 96.2%, respectively. The agreement rate in identifying abnormality of renal artery was also high at 91.94%, the Kappa’s score was 0.8079 (p < 0.001). The angle of renal pelvis and ureter and the position of ureters coming from renal pelvis were also found at high level of sensitivity and specificity (> 85%). The pre-operations play an important role in selecting surgical methods and shortening surgery time. Our results showed that 64-slides CT-scanner could be diagnosed with the high accurate rate in comparison with the in-surgery assessment. We suggested CT-scanner should be considered as gold standard for diagnosing and pre-surgery assessing among patients with UJPO. CONCLUSION The 64-slides CT-scanner showed high sensitivity and specificity in diagnosing the damage of urinary system among patients with UJPO undergoing retroperitoneal laparoscopic surgery at Viet Duc Hospital from 2012 to 2017. CT-scanner should be performed for better diagnosis and treatment and surgery planning in patients with UJPO. REFERENCES 1. Rabah D et al. Ureteropelvic junction obstruction: Does CT angiography allow better selection of therapeutic modalities and better patient outcome? J Endourol. 2004, 18 (5), pp.427-430. 2. Dikranian A.H et al. Intravenous urography in evaluation of asymptomatic microscopic hematuria. J Endourol. 2005, 19 (5), pp.595-597. 3. Dalla Palma L, A. Morra, M. Grotto. CT-urography. Radiol Med. 2005. 110 (3), pp.170-178. 4. Martin X, O. Rouviere. Radiologic evaluations affecting surgical technique in ureteropelvic junction obstruction. Curr Opin Urol. 2001, 11 (2), pp.193-196. 5. Conlin M.J. Results of selective management of ureteropelvic junction obstruction. J Endourol. 2002, 16 (4), pp.233-236. 6. Calder A.D et al. Contrast-enhanced magnetic resonance angiography for the detection of crossing renal vessels in children with symptomatic ureteropelvic junction obstruction: Comparison with operative findings. Pediatr Radiol. 2007. 37 (4), pp.356-361. 7. Kawamoto S, K.M Horton, E.K Fishman. Computed tomography urography with 16- channel multidetector computed tomography: A pictorial review. J Comput Assist Tomogr. 2004, 28 (5), pp.581-587. 8. El-Nahas A.R et al. Role of multiphasic helical computed tomography in planning surgical treatment for pelvi-ureteric junction obstruction. BJU. 2004. 94 (4), pp.582-587. 9. Xie C et al. Comparison between intravenous urography and computed tomography urography in diagnosing ureteropelvic junction obstruction. Nephro-urology monthly. 2011, 3 (4), pp.258-263. 10. El-Ghar, M.E et al. Contrast-enhanced spiral computerized tomography in patients with chronic obstructive uropathy and normal serum creatinine: A single session for anatomical and functional assessment. J Urol. 2004, 172 (3), pp.985-988.