Role of multi-slice CT urography over ultraso-nography in patients with hematuria

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Role of multi-slice CT urography over ultraso-nography in patients with hematuria

Objective: Understanding the role of Multi-slice CT Urography(MSCTU) over Ultrasonography(US) in patients presenting with hematuria. Materials and Methods:Retrospective study enrolled 131 patients presenting with hematuria[microscopic hematuria(n=60)] and macroscopic hematuria(n=71)]who have undergone both MSCTU and US of urinary tract system simultaneously. Results of tests were compared with respective surgical and histopathological analysis of lesion. The cases obtained were bladder carcinoma， ureter carcinoma， renal carcinoma， urinary tract calculi and bladder inflammation. PASW-18thstatistical tool was used for obtaining statistical analysis and final interpretation of results. Results: The sensitivity and specificity of MSCTU and US for recognition of lesions presenting with macroscopic hematuria were 95.38%，83.33% and 81.54%，66.67% respectively and for those with microscopic hematuria were 96.08%，88.89% and 86.27%， 77.8 % respectively. The positive and negative likelihood ratios of MSCTU and US in macroscopic category were 5.73， 0.055 and 2.46， 0.277 respectively while for those in microscopic category were 8.65， 0.044 and 3.88， 0.176 respectively. In context to the sensitivity of MSCTU and US in patients presenting with macroscopic hematuriathedifferenceswere significant (McNemar′s test，P=0.039)suggesting the tests are not similar whereas for those with microscopic hematuria the differences were not significant(McNemar′s test，P=2.68) indicatingsimilarity between these tests.Conclusion:Diagnostic efficacy of MSCTU is found to be far superior over US for patients presenting with macroscopic hematuria， thus current practice of using it as a first line modality seems to be justified. However， for those presenting with microscopic hematuria MSCTU and ultrasonography shows near to similar resultsin accordance to MSCTU， thus US alone seems sufficient to exclude significant urinary tract lesions.

multi-slice computed urography; ultrasonography; urinary tract; microscopic hematuria; macroscopic hematuria

Hematuria is one of the most common conditions confronting clinical urologists and is present in many urinary tract pathology conditions[1].It can originate from any site along the urinary tract and causes of hematuria are diverse， including calculi， neoplasm， infection， trauma， coagulopathy， and renal parenchymal disease[2-3].Presentation may be with symptomatic macroscopic or gross hematuria and asymptomatic microscopic hematuria amongst which asymptomatic ones are commonly identified during routine health checkup[4]. There has always been a considerable debate and confusion regarding the optimal investigation pathway to provide a swift diagnosis in patients with hematuria， especially those with the risk of a life-threatening illness[5].MSCTU uses the newly developed MSCT， which enables isotropic and near isotropic high quality multi-planar imaging and has the advantage of comprehensive evaluation of the entire urinary tract， including the renal pelvis， the ureter， the bladder， and the renal parenchyma[6-7].

1 Participantsand Methods

131 patients (age ranging from 19yrs-86yrs， mean age 65.1)presenting with hematuria，71 macroscopic hematuria and 60microscopic hematuria with homogenous distribution of lesion in the urinary tract who underwent both multi-slice CT urography(MSCTU)and ultrasonography(US) with a confirmed surgical or histopathological report were retrospectively reviewed for lesion detection and were paired to eachother. Patients were referred to the department of radiology by general practitioners， consultants from other departments in the hospital. Microscopichematuria was defined as 3 red blood cells (RBC)/high power field (HPF) on microscopic examination of the centrifuged urine specimen， in 2 of 3 freshly voided， clean catch mid-stream urine samples[8].

Patients on anticoagulation therapy， stent in situ， known allergic reaction to iodinated contrast material， interval of more than four months between the two procedures were our exclusion criteria for the study. After randomly selecting the cases (n=140)from 1st affiliated hospital database those meeting the exclusion criteria(n=9)were discarded and obtained cases were bladder carcinoma， renal cell carcinoma， ureter carcinoma， bladder inflammation and urinary tract calculi. All the images were evaluated at the work station. MSCTU and US images were reviewed. Patient characteristics， presenting symptoms， details of benign and malignant causes of hematuria， presence and location of the urinary tract pathologies were summarized. Each imaging data set was processed completely and the cases were present randomly on first come first basis in our database. Furthermore， we arranged them under either microscopic or macroscopic hematuria group as per initial presentation of the cases. The tests ran were diagnostic test sensitivity， specificity， positive likelihood ratio (LR+)，negative likelihood ratio(LR-)，individually (MSCTU or US)and McNemar′s test.

1.1 CT Protocol

Data were acquired using a 64-slice multi-slice computed tomography(CT)scanner (Siemens， Germany).

Three-phase MSCTU protocol was followed comprising an initial non-contrast phase to detect urinary tract calculi and a second phase， i.e. the nephrographic phase， which was acquired following a delay of 90-100 seconds after administration of 90 ml of intravenous iodinated contrast， to evaluate the renal parenchyma. This was followed by the pyelographic phase taken 5-10 minutes following contrast administration， to evaluate the urothelium from the pelvicaliceal system to the bladder. For diagnostic evaluation， contiguous axial images were reconstructed with 5-mm slice thickness. 2.5 mm thin slices(slice profile 3.2 mm at FWHM)with 50% overlap were obtained for reconstructing coronal and sagittal images of the ureters.

1.2 Statistical analysis

Microsoft-excel 2010 and SPSS 18th for Windows were used for data collection and analysis. The sensitivity， specificity， LR+， LR-， and accuracy of MSCTU and US in detecting the lesions were calculated and compared for further interpretations. The differences in context to sensitivity of the diagnostic tests were observed by using McNemar′s test. A value ofP<0.05 was considered to be significant.

2 Results

On retrospective interpretation， 62 lesions in macroscopic category and 49 lesions in microscopic category were true positive for MSCTU， while US could only identify 53 true positive cases in macroscopic category(Fig 1) and 44 in microscopic category. Furthermore， 3 and 2 false negative cases were detected by MSCTU but US had 12 and 7 false negative cases (Fig 2)in patients presenting with macroscopic and microscopic hematuria respectively. In both the categories，MSCTU diagnosed 1 false positive case and US diagnosed 2 false positive cases(Fig 3).The sensitivity， specificity， LR+， LR-，and overall accuracy of MSCTU and US for recognition of lesions are shown in table 1.In context to the sensitivity of MSCTU and US in patients presenting with macroscopic hematuriathe differences were significant (McNemar test，P=0.039)suggesting the tests are not similar whereas for those with microscopic hematuria the test was not significant (McNemar test ，P=2.68)indicating similarity between these tests.

A.Axial excretory phase image shows bladder mass; B.Three dimensional VRT image reconstruction of MSCT urography shows filling defect in the bladder indicating bladder mass;C.The ultrasonography also shows urinary bladder mass

Fig 1 86 year-old female with macroscopic hematuria and bladder mass

A.Axial excretory phase image shows calculi in the right lower segment of the ureter; B.Coronal image of MSCT urography also shows right ureteric calculi with bilateral hydroureteronephrosis and non-functioning right kidney; C.3D VRT shows non-functioning right kidney; D.Ultrasonography only shows right hydroureteronephrosis failing to show calculi in the lower ureter

Fig 2 47 year-old male with microscopic hematuria and right ureteric calculi

3 Discussion

Our results， in a group of patients being investigated for macroscopic hematuria showed muchhigher sensitivity， specificity， and accuracy of MSCTU than that of US. However， for those presenting with microscopic hematuria USwas found to be near to similar in sensitivity and specificity to that of MSCTU as compared to macroscopic

A.Ultrasonography shows urinary bladder mass; B.Axial MSCT urography excretory phase image shows bladder diverticuli but not bladder massFig 3 82 year-old male who presented with macroscopic hematuria

Tab 1 Sensitivity，specificity，positive，negative likelihood ratio and accuracies of macroscopic and microscopic hematuria

group.Our study further support the appropriateness of this technique as showed by Cauberg et al[9].that in patients who presented with microscopic hematuria， ultrasonography was sufficient to exclude significant urinary tract lesions. Our study further showed the difference in context to sensitivity of the diagnostic test between MSCTU and US for category macroscopic hematuria were statistically significant (McNemar′s test，P=0.039) suggesting the test are not similar in producing identical resultswhileforthose with microscopic hematuria the differences was not significant(McNemar′s test，P=2.68) suggesting the tests are similar and either of them is capable of producing identical result. Some guidelines suggest MSCTU being appropriate for gross hematuria and not for microscopic hematuria unless there is high suspicion from baseline investigations[10]， and this however may be an appropriate economic practice[11].Our study supports the use of US being sufficient to exclude the cause of microscopic hematuria and it is obvious from our study that running these tests in series will effectively decrease omissions of overwhelming urinary tract pathologies， thus is recommended wherever it is necessary and technically feasible. Our study has several limitations. It was a retrospective review that included a small number of patients and thus has a potential for inclusion bias. The US we reviewed were performed by several radiologists hence the inter-observer bias were inevitable due to the retrospective nature of our study. MSCTU can expose the patient to considerable radiation and the risks of medical exposure to ionizing radiation should not be underestimated[12].The greater the number of acquisition greater the radiation hazard. In our technique， the three phase protocol has a dose of around 12 mSv， which is comparable with the dose of other multiphase techniques， such as liver or pancreas CT， as practiced in our department.

4 Conclusion

In conclusion，for patients presenting with macroscopic hematuria over all diagnostic efficacy of MSCTU outweighs US， thus the current practice of using it as a first line modality should be continued， while for patients presenting with microscopic hematuria US seemed to produce near identical test results to that of MSCTU indicating US being sufficient to exclude significant cause of microscopic hematuria.

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DUWADI Ayushma1，2，JIN Ji-yang2

(1.SchoolofMedicine，SoutheastUniversity，Nanjing210009，China；2.DepartmentofRadiology，ZhongdaHospital，SoutheastUniversity，Nanjing210009，China)

10.3969/j.issn.1671-6264.2015.03.022

JIN Ji-yang E-mail:jy_jin@126.com

format] DUWADI Ayushma，JIN Ji-yang.Role of multi-slice CT urography over ultrasonography in patients with hematuria[J].J Southeast Univ(Med Sci Edi)，2015，34(3):420-424.

R445; R695 [Document code] A [Article ID] 1671-6264(2015)03-0420-05

[Received data] 2014-11-06 [Revised data] 2015-01-13

[Author] DUWADI Ayushma (1986 -)，Female，Nepalese，Nepal，Postgraduate student.E-mail:ayushma1@hotmail.com