Multi-detector row CT urography in the evaluation of hematuria

[Imaging capabilities in upper urothelial malignancies differentiation]

Aim of our study is to analyze sensitivity and specificity of imaging procedures in characterization upper urothelial malignancies, according to algorithm suggested by American Urology Association.

MATERIAL AND METHODS

We analyzed 242 patients with kidney tumor masses who had been operated during 2006/2007 at Urological clinic in Belgrade. Due to pathohistological exam 210 patients had kidney parenchyma and 32 patients upper urothelial kidney tumor.

RESULTS

According to tumor stage, computed tomography was sufficient and definitive diagnostic tool concerning both renal epithelial and upper urothelial malignancy. Only in four cases 1.60% (4/242; CT in 3/4, MRI 1/4) preoperative site of origin was different from histopathology findings. This mislead to inappropriate surgery plan.

CONCLUSION

Familiarity with limitations and capabilities of imaging modalities is crucial for appropriate diagnosis. It should respect algorithm but has to be individual adapted.

Imaging findings of genitourinary tumors in the elderly

Aging-correlated pathologies are atherosclerosis, arterial hypertension, diabetes mellitus, bacterial infections, and malnutrition. The progressive impairment of renal function is the cause of the drug-induced renal pathologies: direct damage induced by nephrotoxic drugs or indirect damage induced by decreased renal excretion of serum molecules. In the elderly, an increase in different pathologies occurs in the genitourinary tract. Among these pathologies, an increase in neoplastic disorders is present; at the same time, several non-neoplastic pathologies are more frequent in old patients. This article considers first the neoplastic genitourinary pathologies and second the non-neoplastic genitourinary pathologies.

Bladder cancer detection with CT urography in an Academic Medical Center

PURPOSE

To evaluate the performance characteristics of computed tomographic (CT) urography for the detection of bladder cancer in patients at risk for the disease.

MATERIALS AND METHODS

Institutional review board approval was obtained for this retrospective HIPAA-compliant review of medical records of 2600 consecutive patients undergoing CT urography. Of these, 838 CT urograms in 779 patients (449 men, mean age of 62 years, range of 27-92 years; 330 women, mean age of 56 years, range of 18-86 years) evaluated for hematuria or a history of urothelial cancer, who had undergone cystoscopy within 6 months of the CT urogram, were included in the study. Clinical reports of CT urograms containing a bladder lesion interpreted as suspicious for malignancy were classified as positive. All others were classified as negative. Cystoscopy reports were classified as positive if a lesion underwent biopsy or was resected or negative if no lesion was detected. Performance characteristics for both CT urography and cystoscopy were determined by using pathologic findings or clinical follow-up as the reference standard. Ninety-five percent confidence intervals were estimated for each test characteristic.

RESULTS

The overall sensitivity, specificity, accuracy, positive predictive value, and negative predictive value (NPV) for bladder cancer detection were 79% (117 of 149), 94% (649 of 689), 91% (766 of 838), 75% (117 of 157), and 95% (649 of 681) for CT urography and 95% (142 of 149), 92% (634 of 689), 93% (776 of 838), 72% (142 of 197), and 99% (634 of 641) for cystoscopy. The NPV of CT urography was higher in patients evaluated for hematuria alone (98%, 589 of 603). However, the accuracy of CT urography was considerably lower in patients with a prior urothelial malignancy (78%, 123 of 158).

CONCLUSION

CT urography is an accurate noninvasive test for detecting bladder cancer in patients at risk for the disease. The high NPV of CT urography in patients with hematuria may obviate cystoscopy in selected patients.

[MDCT urography with and without use of diuretics]

PURPOSE

To optimize the MDCT urogram protocol for assessment of the upper tracts. To assess the value of furosemide injection.

MATERIALS AND METHODS

Prospective study comparing excretory phase imaging at 450 seconds in 67 patients assigned to 3 groups: a group without furosemide (f=0), a group with 20 mg furosemide (f=20), and a group with 10 mg furosemide (f=10). 3D MIP images were generated. Two experienced radiologists blinded to protocol specifications analyzed the quality of opacification the upper tracts, divided in 8 segments and urine density at the renal pelvis.

RESULTS

The injection of 20 mg of furosemide significantly improved the opacification of the upper tracts with complete or near complete opacification in 82.6% of cases compared to 43.5% and 19% for the F=10 and f=0 groups respectively. Density measurements were 5 times less for the f=20 and f=10 groups compared to the f=0 group.

CONCLUSION

Furosemide is useful for MDCT urography by improving upper tract opacification and filling: the reduced contrast concentration in the better distended and fully filled upper tracts improves evaluation of ureteral lumen and wall abnormalities.

Imaging of hematuria

Hematuria may have a number of causes, of which the more common are urinary tract calculi, urinary tract infection, urinary tract neoplasms (including renal cell carcinoma and urothelial tumors), trauma to the urinary tract, and renal parenchymal disease. This article discusses the current status of imaging of patients suspected of having urologic causes of hematuria. The role of all modalities, including plain radiography, intravenous urography or excretory urography, retrograde pyelography, ultrasonography, and multidetector computed tomography (MDCT) in evaluation of these patients is discussed. The article highlights the current status of MDCT urography in imaging of patients with hematuria, and discusses various-often controversial-issues, such as optimal protocol design, accuracy of the technique in imaging of the urothelium, and the significant issue of radiation dose associated with MDCT urography.

Hematuria: portal venous phase multi detector row CT of the bladder--a prospective study

PURPOSE

To prospectively determine the accuracy of portal venous phase helical multi-detector row computed tomography (CT) for bladder lesion evaluation in patients with hematuria by using cystoscopy as the reference standard.

MATERIALS AND METHODS

The study was approved by the institutional review board for human investigation, and informed consent was obtained from all patients. This study included 118 patients (91 male, 27 female; age range, 15-87 years; mean age +/- standard deviation, 62 years +/- 14) who underwent portal venous phase multi-detector row CT (scanning delay, 70 seconds; section thickness, 2 mm) and conventional cystoscopy because of painless gross hematuria or recurrent microscopic hematuria. Two reviewers with different experience levels independently evaluated the bladder for lesions at CT in a prospective fashion. The kappa statistic was used to determine the per lesion and per patient agreement between the two reviewers and between the CT and cystoscopic findings. The sensitivity and specificity of multi-detector row CT for bladder lesion detection were analyzed for numbers of lesions and for numbers of patients.

RESULTS

Multi-detector row CT showed excellent per lesion (kappa = 0.839) and per patient (kappa = 0.881) agreement between the two reviewers. Respective per lesion and per patient agreement between the CT and cystoscopic findings was also excellent in the first (kappa = 0.866 and kappa = 0.881) and second (kappa = 0.802 and kappa = 0.863) reviewers. The sensitivity and specificity of multi-detector row CT were 89%-92% and 88%-97%, respectively, in the per lesion analysis and 95% and 91%-93%, respectively, in the per patient analysis for both reviewers. All statistical parameters of diagnostic accuracy were similar between the two reviewers (P > .05).

CONCLUSION

Portal venous phase multi-detector row CT can provide high accuracy and reader agreement for bladder lesion detection in patients with painless gross hematuria and recurrent microscopic hematuria; these results indicate that multi-detector row CT can be used as the initial bladder examination in such patients.

Accuracy of intermediate dose of furosemide injection to improve multidetector row CT urography

OBJECTIVE

Evaluate the usefulness of intermediate dose furosemide to improve visualization of the intrarenal collecting system and ureter using MDCTU.

MATERIALS AND METHODS

Two groups of 100 patients without urinary tract disease or major abdominal pathology underwent MDCTU. Group I (various abdominal indications) was performed without any additional preparation and Group II (suspicion of urinary tract disease) 10 min after injection of furosemide (20mg). MIP images of the excretory phase were post-processed. Maximal short-axis diameter of the pelvis and ureter were measured on axial images for all phases. Visualization of the collecting system wall and the identification of the whole ureter were assessed.

RESULTS

Mean pelvic diameter before contrast was (7.4mm, S.D.+/-2.7; 13.4mm, S.D.+/-4.1), on cortico-medullary phase (8.4mm, S.D.+/-4.2; 14.3mm, S.D.+/-4), on nephrographic phase (8.1mm, S.D.+/-2.5; 14.8mm, S.D.+/-4) and on excretory phase (9.7 mm, S.D.+/-3.4; 14.9 mm, S.D.+/-4.5), respectively, for Groups I and II. Intrarenal collecting system wall was clearly identified on both corticomedullary and nephrographic phases in 91% of Group II against 20% of Group I. Opacification of the entire ureter was excellent on excretory phase in 96% of Group II against 13% of Group I. The difference between the mean values for the two groups was statistically significant for all phases (p<10(-9)).

CONCLUSION

Intermediate-dose furosemide (20mg) before MDCTU is a very simple add-on for accurate depiction of pelvicalyceal details and collecting system wall without artefacts. The procedure is associated with a constant and complete visualisation of the entire urete.

Multislice CT-angiography in percutaneous postinterventional hematuria and kidney bleeding: Influence of diagnostic outcome on therapeutic patient management. Preliminary results

BACKGROUND

The aims of this study were to assess the value of multislice CT-angiography (MS-CT-A) in percutaneous postinterventional kidney bleeding and to determine the influence of diagnostic outcome on therapeutic patient management. A recommendation for the interdisciplinary patient work-up for the emergency room was offered.

METHODS

Between April 2003 and January 2006, 12 patients with hematuria and clinically suspected renal bleeding underwent MS-CT-A for emergency diagnostic assessment. The spectrum of kidney injuries on CT was analyzed according to an organ-scaling scheme. The efficacy of MS-CT-A with regard to confirmation of active arterial bleeding was evaluated as well as the therapeutic consequences for patient management.

RESULTS

In seven patients (59%) staged grade V renal injury, active renal arterial bleeding was detected on CT-A. Patients immediately underwent therapeutic angiography with confirmation of arterial bleeding and successful embolization. Four patients (33%) were staged grade I renal injury with subcapsular kidney hematoma but no active hemorrhage. Therefore, these patients were not exposed to further therapeutic intervention. One patient (8%) was diagnosed grade II renal injury with superficial cortical renal parenchyma tear and no active bleeding on CT-A.

CONCLUSIONS

MS-CT-A is a valuable, fast and objective emergency tool for assessment of postinterventional renal hemorrhage. Detection of contrast material extravasation to affirm ongoing arterial bleeding and to localize bleeding site at the level of segmental or interlobar renal artery is a predictor for the need for further treatment and justifies therapeutic radiological or surgical management.

Multidetector computed tomography urography (MDCTU) for diagnosing urothelial malignancy

Multidetector computed tomography (MDCT) is well established for the detection of stones and renal masses, but more recently MDCT urography (MDCTU) is becoming widely used for examination of the entire urinary tract aimed specifically for diagnosing urothelial lesions. Evidence is rapidly accumulating to support the use of MDCTU in this manner. Familiarity with the MDCTU signs of urothelial malignancy is a prerequisite for optimum radiological practice. This article provides a review of the appearances of transitional cell cancer in the upper urinary tract and bladder.

Renal Papillary Necrosis: Review and Comparison of Findings at Multi–Detector Row CT and Intravenous Urography

Renal papillary necrosis is not a pathologic entity but rather a descriptive term for a condition--necrosis of the renal papillae--that has various possible causes. The renal medulla and papillae are vulnerable to ischemic necrosis because of the peculiar arrangement of their blood supply and the hypertonic environment. The etiology of renal papillary necrosis includes diabetes, analgesic abuse or overuse, sickle cell disease, pyelonephritis, renal vein thrombosis, tuberculosis, and obstructive uropathy. Renal papillary necrosis has been diagnosed with the use of intravenous urography and ultrasonography, but contrast material-enhanced computed tomography (CT) may better depict a full range of typical features, including contrast material-filled clefts in the renal medulla, nonenhanced lesions surrounded by rings of excreted contrast material, and hyperattenuated medullary calcifications. In the presence of papillary sloughing, CT may depict hydronephrosis and filling defects in the renal pelvis or ureter, which also may contain calcifications. During healing, the epithelialized papillary tip appears blunted. Shrinkage of the kidney, a common sequela, also may be detected at CT. Multi-detector row CT depicts these and other features more clearly and directly than single-detector row CT, given the advantages of thinner sections and multiplanar reformation, and it may help identify the condition at an earlier stage, when effective treatment can reverse the ischemic process. Familiarity with the CT features of the condition therefore is useful for its successful diagnosis and management.

Sonography in Benign and Malignant Renal Masses

Ultrasonography and CT have allowed improved detection of renal mass lesions. Though ultrasonography is less sensitive in the characterization of the renal mass lesions, it is often the first imaging modality for evacuation of the kidneys. This article gives an overview of the benign and malignant renal mass lesions and the role of ultrasonography in their characterization.

Multi-detector row CT urography on a 16-row CT scanner in the evaluation of urothelial tumors

The purpose of this study was to assess the role of multi-detector row CT urography (MDCTU), on a 16-row CT scanner in the evaluation of patients with painless hematuria, with emphasis placed in the detection of urothelial tumors. We retrospectively reviewed the MDCT urographies of 75 patients, referred for painless hematuria. The CT protocol included unenhanced images, obtained with a detector configuration of 16x1.5 mm and pitch of 1.2, nephrographic and excretory-phase images, obtained with a detector collimation of 16x0.75 mm and pitch of 1.2. Axial and coronal reformatted images were evaluated. Three-dimensional reformation of the excretory-phase images was performed using the volume-rendering technique. The standard of reference included clinical and imaging follow-up, cystoscopic, surgical and histologic findings. In 55 (73%) of 75 patients, the cause of hematuria was identified on MDCTU; the most common cause was urothelial cancer, including seven tumors with a diameter equal or smaller than 0.5 cm in diameter. Sixteen-row MDCTU provided satisfactory results in the investigation of patients with painless hematuria. The main advantage of the technique is its ability to detect uroepithelial malignancies.

Understanding multislice CT urography techniques: many roads lead to Rome

CT urography has emerged as a serious alternative to conventional urography by utilizing the advantages of modern multislice CT techniques for the visualization of the entire upper urinary tract. Several different examination techniques have been developed in multislice CT (MSCT) urography for improving the opacification and distension of the urinary tract. All efforts in performing MSCT urography have to compromise between the best possible image quality and a reasonably low radiation exposure. Initial low-dose examination protocols are already available. Operating modern MSCT urography properly is not difficult, but it presupposes basic knowledge on the variety of current MSCT urography techniques, including such issues as present-day indications, split-bolus injection, compression, saline infusion, low-dose diuretic administration, hybrid scanning, timing of the acquisition delay, examination protocols, postprocessing, image analysis, and radiation exposure. This article is not intended to provide guidelines of how to conduct MSCT urography, but everyone will be able to understand the functionality of several robust operating MSCT urography techniques, which helps making an individual selection for the clinical practice. In the near future, systematic studies are awaited evaluating the morphologic and diagnostic accuracy of MSCT urography regarding diverse urinary tract disorders.

Maximizing clinical information obtained by CT

CT scanning is an integral part of the urologist's practice today. It is the most commonly used imaging modality and the one with which urologists are most familiar. CT urography, CT angiography, and 3D reconstruction enable the urologist to perform comprehensive evaluations of patients who have different urologic diseases, using a single imaging modality. It is thus prudent that urologists become familiar with CT applications, to maximize the clinical information available from them.

Applications of Computed Tomography in Renal Imaging

There have been huge advances in CT technology since its introduction more than 30 years ago. Modern, multislice CT scanners are fast and produce truly volumetric data, allowing it to be reconstructed in almost any plane. In this article, we explore the impact of these developments on the use of CT in imaging of the renal tract. Whilst it may take the radiologist longer to review and process the increased amount of data that is produced, diagnostic accuracy is unquestionably improved and new and exciting challenges are presented to the radiologist as he learns to manipulate and interpret the data in a way that he has never done before.

Opacification of the genitourinary collecting system during MDCT urography with enhanced CT digital radiography: nonsaline versus saline bolus

OBJECTIVE

The purpose of this study was to determine whether a saline bolus during CT urography improves urinary collecting system opacification and whether the addition of enhanced CT digital radiography (CTDR) improves urinary collecting system visualization with or without a saline bolus.

MATERIALS AND METHODS

One hundred eight CT urography and enhanced CTDR examinations were reviewed. Fifty-four patients were given a saline bolus during CT urography, and 54 patients underwent CT urography without a saline bolus. Urinary collecting system opacification was evaluated by group (saline vs nonsaline), imaging technique (CT urography alone vs CT urography plus enhanced CTDR), number of enhanced CTDR images, and site of nonopacified urinary segments. Using a multivariate logistic regression model, we determined significance of variables and odds of complete opacification.

RESULTS

In the saline group, 248 nonopacified sites were identified on CT urography alone and 95 sites with CT urography plus enhanced CTDR. In the nonsaline group, 185 nonopacified sites were identified on CT urography alone and 59 sites with CT urography plus enhanced CTDR. Combining both groups, 433 nonopacified sites were identified with CT urography alone and 154 sites with CT urography plus enhanced CTDR. Multivariate logistic regression showed significance for group (p = 0.010), imaging method (p < 0.0001), number of enhanced CTDR images (p = 0.048), and site of segment opacification (p < 0.0001). The renal pelvis shows the greatest odds and the distal ureter the lowest odds for complete opacification by group or imaging method.

CONCLUSION

The addition of a saline bolus offers no improvement, whereas the addition of enhanced CTDR offers significant improvement in collecting system opacification during CT urography.

Multidetector CT urography: comparison of two different scanning protocols for improved visualization of the urinary tract

The goal of this study was to evaluate different CT scanning protocols on the depiction of the urinary tract by multidetector CT. The authors retrospectively reviewed 55 consecutive patients who underwent CT scanograms. Two groups of patients were included: renal donors (n=29) and hematuria patients (n=26). For the renal donor protocol, 120 mL of iodinated contrast was injected and a CT scanogram was obtained after a 5-minute delay. For the hematuria CT urography protocol, 100 mL of contrast was followed by a 250 mL normal saline drip and CT scanograms acquired after an 8-minute delay. Urinary tracts from both imaging protocols were then divided into four segments and evaluated by consensus reading of two experienced radiologists rated on a scale of 0 to 2. Complete visualization of the renal pelvis and the proximal, middle, and distal ureter for the renal donor protocol was noted to be 86%, 57%, 45%, and 52% and for that of the CT urography protocol to be 75%, 65%, 40%, and 44%, respectively. Comparing scanograms of the renal donor protocol and the CT urography protocol, there was no statistically significant difference in the depiction of renal pelvis or the proximal, middle or distal ureteral region (P=0.1625, 0.3226, 0.8636, and 0.6145, respectively). The study demonstrates that there is no significant difference between the CT urography protocol and the renal donor protocol in the depiction of the urinary tract.

Transitional Cell Carcinoma of the Upper Urinary Tract: Spectrum of Imaging Findings

Transitional cell carcinoma (TCC) accounts for up to 10% of neoplasms of the upper urinary tract and usually manifests as hematuria. Imaging plays an important role in assessment of upper tract disease, unlike in bladder TCC, diagnosis of which is usually made at cystoscopy. Traditional imaging modalities, such as excretory urography, retrograde pyelography, and ultrasonography, still play pivotal roles in diagnosis of upper tract TCC, in combination with endourologic techniques. The multicentric nature of TCC makes assessment of the entire urothelium essential before treatment. The advent of minimally invasive surgery, which allows renal preservation in selected patients, makes accurate tumor staging mandatory to determine the appropriate therapy; staging is usually performed with computed tomography (CT) or magnetic resonance (MR) imaging. Vigilant urologic and radiologic follow-up is warranted to assess for metachronous lesions and recurrence. The emerging technique of CT urography allows detection of urinary tract tumors and calculi, assessment of perirenal tissues, and staging of lesions; it may offer the opportunity for one-stop evaluation in the initial assessment of hematuria and in follow-up of TCC. Similar MR imaging protocols can be used in patients who are not candidates for CT urography, although detection of urinary tract calcifications may be suboptimal.

CT urography of urinary diversions with enhanced CT digital radiography: preliminary experience

OBJECTIVE

The purpose of this study was to determine if 3D-rendered CT urography (CTU) depicts both normal and abnormal findings in patients with urinary diversions and if the addition of contrast-enhanced CT digital radiography (CTDR) improves opacification of the urinary collecting system.

MATERIALS AND METHODS

Thirty CTU and contrast-enhanced CTDR examinations were performed in 24 patients who underwent cystectomy for bladder cancer. Indications for evaluation included hematuria, tumor surveillance, or suspected diversion malfunction. All examinations were evaluated without knowledge of the stage or grade of a patient's tumor and were compared with the clinical records. Opacification of the urinary collecting system was evaluated with 3D CTU alone, contrast-enhanced CTDR alone, and combined CTU and CTDR.

RESULTS

Nine abnormalities were identified including distal ureteral strictures (n = 4), vascular compression of the mid left ureter (n = 1), scarring of the mid right pole infundibulum (n = 1), bilateral hydronephrosis and hydroureter (n = 1), urinary reservoir calculus (n = 1), and tumor recurrence invading the afferent limb of the neobladder (n = 1). Eight of the nine detected abnormalities were surgically or pathologically confirmed. All abnormalities were identified on all three imaging techniques but were best seen on 3D CTU and enhanced CTDR images. Incomplete opacification of the urinary collecting system occurred in 17 patients with CTU alone, 12 patients with contrast-enhanced CTDR alone, and nine patients with combined CTU and contrast-enhanced CTDR. Compared with CTU alone, the combined technique of 3D CTU and contrast-enhanced CTDR improved opacification by a statistically significant difference (p = 0.037).

CONCLUSION

CTU with 3D rendering can accurately depict both normal and abnormal postoperative findings in patients with urinary diversions. Adding enhanced CTDR can improve visualization of the urinary collecting system.

[New techniques in computed tomography. Significance for urology]

Computed tomographic (CT) imaging has become the modality of choice for the assessment of patients with urological malignancies. Recently, multi-slice CT imaging was introduced, providing faster acquisition times and higher resolution leading to improved image quality. Several studies show that thin-slice, high-resolution acquisition strategies lead to an improved accuracy for T-staging, especially of renal cell carcinomas. Three-dimensional post-processing techniques for the visualization of the vascular supply as well as the ureter (CT-angiography and CT-urography) are helpful for surgical planning. Compared to conventional imaging strategies unenhanced CT images render higher sensitivities and specificities for detecting stone disease in patients with acute flank pain. In the USA unenhanced CT imaging has almost replaced conventional urography, as no contrast agent is administered and the examination time is shorter. PET/CT examinations provide information on the morphology and function of tumors in one examination. However, there are only few data available for the assessment of urologic tumors.

CT Urography

With the recent introduction of multi-detector row helical computed tomography (CT), the radiologic evaluation of patients with urologic disease has changed rapidly. Two major approaches to CT urography have been developed. The first approach combines axial CT with timed excretory urography (EU) performed by using conventional radiography, digital radiography, or CT scanned projection radiography (SPR). This approach produces traditional projection urograms, and the timed imaging technique is familiar to radiologists and clinicians. Additional excretory phase CT can be performed when the EU findings are positive or indeterminate. Improved CT SPR processing technology produces radiographlike images, thus eliminating patient transportation between the CT and urography suites or the necessity for a CT suite with a ceiling-mounted x-ray tube and a modified CT tabletop for performance of EU. The second approach to CT urography combines axial CT with thin-section excretory phase CT. The near-isotropic volume data set enables creation of high-resolution two- and three-dimensional reformatted images. However, the increased amount of radiation and the time required for data manipulation are concerns. Further studies evaluating large numbers of patients with various urothelial abnormalities will be necessary to determine the optimal CT urography technique for clinical practice.