PATIENTS AT HIGH RISK FOR UPPER TRACT UROTHELIAL CANCER: EVALUATION OF HYDRONEPHROSIS USING HIGH RESOLUTION MAGNETIC RESONANCE UROGRAPHY

In search of a consensus: evaluation of the patient with hematuria in an era of cost containment

OBJECTIVE

The purpose of this article is to describe the current consensus guidelines for nonimaging triage and ultimate preferred imaging approach for the patient with unexplained hematuria.

CONCLUSION

Numerous consensus guidelines from varying societies have outlined preferred imaging pathways for the patient with unexplained urologic causes of hematuria. Future guidelines will need to take into account disease prevalence, radiation considerations, and cost.

Collecting duct carcinoma of the kidney: Imaging observations of a rare tumor

Collecting duct carcinoma (CDC) is a rare type of renal neoplasm. Early diagnosis is possibly the only factor leading to a prolonged survival for patients with CDC. The purpose of the present study was to characterize the imaging features of CDC and improve its diagnosis. Radiological data of six patients were retrospectively reviewed by three experienced radiologists, including six cases examined with non-contrast computed tomography (CT) scans, five with contrast-enhanced CT scans, one with magnetic resonance urography, one with renal dynamic imaging and two with conventional whole-body ¹⁸F-fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT scans. All patients were pathologically confirmed with CDC. In total, seven tumors were detected in the six cases, with a mean size of 5.3 cm. Of the tumors, two were solid and the rest were complex solid and cystic. In addition, six tumors were located in medullary areas and only one tumor was found in the cortical location. Cystic components were observed in five tumors. Weak enhancements were observed in all six tumors examined with contrast-enhanced CT, and heterogeneous enhancements were also observed in the majority of these tumors with the exception of one tumor. Infiltrative growth and expansible growth were found in five and two tumors, respectively. Metastatic lesions were detected in all six patients. On MR urography, the involved kidney exhibited similar imaging observations to the CT scan. Renal dynamic imaging revealed a decreased renal function in the involved kidney and an increased renal function in the contralateral kidney. On PET/CT imaging, a marked uptake of ¹⁸F-FDG was found in primary and metastatic lesions. The results of the present study indicated that medullary location, weak and heterogeneous enhancement, infiltrative growth, damage of renal function in the involved kidney and a marked uptake of ¹⁸F-FDG are imaging observations commonly identified in patients with CDC. When a renal tumor exhibits these imaging features, CDC may be suggested as a valuable differential diagnosis.

Magnetic resonance urography vs computed tomography urography in the evaluation of patients with haematuria

PURPOSE

This study was done to evaluate by direct comparison the image quality of magnetic resonance urography (MRU) and computed tomography urography (CTU) and to assess the diagnostic confidence of the two techniques in detecting urothelial malignancy in patients with haematuria

MATERIALS AND METHODS

Thirty-five patients with haematuria underwent both CTU and MRU. Two different investigators evaluated calyceal, renal pelvis, ureteral and bladder visibility. Their diagnostic confidence in detecting urothelial malignancy with the two procedures was assessed. A Wilcoxon matched-pairs test was performed to compare results. Inter-reader agreement was calculated by weighted kappa (WK) statistic. Patient history (further examinations, cystoscopy and histological specimens) was considered as reference standard to calculate receiver operating characteristic (ROC) curves of diagnostic confidence.

RESULTS

CTU provided better visibility of urothelial structures (p<0.01) and allowed for greater diagnostic confidence (ROC area 0.994 vs. 0.938) than MRU, with a good inter-reader agreement (WK=0.62). Nevertheless, in obstructive patients with impaired excretory function, MRU, thanks to the static-fluid technique, offered better visualisation than CTU.

CONCLUSIONS

There is a potential role for MRU in urinary tract imaging, but as diagnostic confidence in detecting urothelial malignancy is poorer than in CTU, it might be stareserved for patients at low risk for malignancy and for evaluating obstructed patients.

Magnetic Resonance Urography in Obstructive Uropathy

BACKGROUND

Urinary obstruction is one of the few reversible causes of renal failure. Early diagnosis and treatment can salvage the kidney. Presently intravenous urography, ultrasonography, computed tomography and magnetic resonance imaging are in vogue to detect the cause and demonstrate the site of obstruction.

METHODS

An evaluation of imaging technique in obstructive uropathy was undertaken in a group of 25 patients.

RESULT AND CONCLUSION

Magnetic resonance urography delivered highest accuracy amongst the techniques studied.

Multidetector computerized tomography urography is more accurate than excretory urography for diagnosing transitional cell carcinoma of the upper urinary tract in adults with hematuria

PURPOSE

It is debatable whether traditionally used excretory urography or the recently introduced multidetector computerized tomography urography is more accurate for diagnosing upper urinary tract transitional cell carcinoma. We compared accuracy measures of both methods for diagnosing upper urinary tract transitional cell carcinoma in adult patients with hematuria.

MATERIALS AND METHODS

We retrospectively analyzed consecutive adult patients with hematuria undergoing excretory urography and multidetector computerized tomography urography before any surgery, intervention or treatment from April 2004 to December 2006 in our hospital. The presence of upper urinary tract transitional cell carcinoma on excretory urography and multidetector computerized tomography urography was reviewed independently by 2 uroradiologists who were blinded to clinical information and other imaging results. Final diagnosis of upper urinary tract transitional cell carcinoma was confirmed by histological results. Measures of the diagnostic accuracy of excretory urography and multidetector computerized tomography urography for upper urinary tract transitional cell carcinoma were calculated and compared with reference to the final diagnosis.

RESULTS

Of 34 men and 26 women with hematuria (mean age 60.73 +/- 12.95 years) 19 (31.7%) had a final diagnosis of 24 upper urinary tract transitional cell carcinomas. The sensitivity, specificity and accuracy of excretory urography were 0.750, 0.860 and 0.849, respectively. In contrast, the sensitivity, specificity and accuracy of multidetector computerized tomography urography were 0.958, 1.000 and 0.996, respectively. Overall the area under the receiver operating characteristic curve for multidetector computerized tomography urography was significantly larger than that for excretory urography (0.978 vs 0.815, p = 0.005).

CONCLUSIONS

Multidetector computerized tomography urography is more sensitive, specific and accurate than excretory urography in the diagnosis of upper urinary tract transitional cell carcinoma in adult patients with hematuria. Therefore, multidetector computerized tomography urography rather than excretory urography should be the first choice noninvasive imaging modality for diagnosing upper urinary tract transitional cell carcinoma.

MR urography versus retrograde pyelography/ureteroscopy for the exclusion of upper urinary tract malignancy

AIM

To evaluate the diagnostic performance of magnetic resonance urography (MRU) versus retrograde pyelography and/or ureteroscopy (RPU) in the detection of upper urinary tract neoplasms.

MATERIALS AND METHODS

This retrospective study included 35 patients with suspected upper urinary tract malignancy who underwent MRU and RPU within 6-months in our institution during the study period (February 2002 to January 2007). MRU and RPU reports were reviewed and results recorded. For each patient, the urinary tract was sub-divided into four regions for analysis: left kidney/renal pelvis, left ureter, right kidney/renal pelvis, and right ureter. MRU and RPU results for each patient were compared to a reference standard and the diagnostic performance of both techniques was compared.

RESULTS

A total of 113 regions were analysed on MRU and 90 regions on RPU. Nineteen neoplasms were identified. Sensitivity, specificity, positive predictive value, and negative predictive value for the detection of urinary tract neoplasms were 63, 91, 60, and 92% for MRU, respectively, and 53, 97, 83, and 88% for RPU, respectively. These differences were not statistically significant (p>0.05).

CONCLUSION

The high negative predictive value of MRU in the present series supports its use as a non-invasive screening examination for excluding the presence of upper urinary tract malignancy.

Magnetic resonance urography

Excellent contrast resolution and lack of ionizing radiation make magnetic resonance urography (MRU) a promising technique for noninvasively evaluating the entire urinary tract. While MRU currently lags behind CT urography (CTU) in spatial resolution and efficiency, new hardware and sequence developments have contributed to a resurgence of interest in MRU techniques. By combining unenhanced sequences with multiphase contrast-enhanced and excretory phase imaging, a comprehensive assessment of the kidneys, ureters, bladder, and surrounding structures is possible with image quality rivaling that obtained with other techniques. At the same time, formidable challenges remain to be overcome and further clinical validation is necessary before MRU can replace other forms of urography. In this article, we demonstrate the current potential of MRU to demonstrate a spectrum of urologic pathology involving the kidneys, ureters, and bladder while discussing the limitations and current status of this evolving technique.

[Diagnostic procedures in upper urinary tract urothelial carcinoma]

Upper urinary tract transitional cell carcinomas represent 5-6% of all urothelial carcinomas. Macroscopic hematuria is the most common symptom. The diagnostic algorithm contains medical history, clinical investigation, cystoscopy, urinary cytology, ultrasound and intravenous urography. When suspected, a complementary retrograde pyeloureterography with collecting selective urinary cytology is conducted. When radiological findings are doubted or when conservative treatment is planned, an ureterorenoscopy for biopsy of the suspected area is indicated. Computed tomography and magnetic resonance tomography is used to define the local extension of invasive tumors and to detect metastases. The use of urinary markers in the diagnosis of upper urinary tract urothelial carcinoma has to be evaluated in prospective trials.

MR urography: techniques and clinical applications

Magnetic resonance (MR) urography comprises an evolving group of techniques with the potential for allowing optimal noninvasive evaluation of many abnormalities of the urinary tract. MR urography is clinically useful in the evaluation of suspected urinary tract obstruction, hematuria, and congenital anomalies, as well as surgically altered anatomy, and can be particularly beneficial in pediatric or pregnant patients or when ionizing radiation is to be avoided. The most common MR urographic techniques for displaying the urinary tract can be divided into two categories: static-fluid MR urography and excretory MR urography. Static-fluid MR urography makes use of heavily T2-weighted sequences to image the urinary tract as a static collection of fluid, can be repeated sequentially (cine MR urography) to better demonstrate the ureters in their entirety and to confirm the presence of fixed stenoses, and is most successful in patients with dilated or obstructed collecting systems. Excretory MR urography is performed during the excretory phase of enhancement after the intravenous administration of gadolinium-based contrast material; thus, the patient must have sufficient renal function to allow the excretion and even distribution of the contrast material. Diuretic administration is an important adjunct to excretory MR urography, which can better demonstrate nondilated systems. Static-fluid and excretory MR urography can be combined with conventional MR imaging for comprehensive evaluation of the urinary tract. The successful interpretation of MR urographic examinations requires familiarity with the many pitfalls and artifacts that can be encountered with these techniques.

Avaliação das fístulas urogenitais por urorressonância magnética

OBJETIVO: As fístulas vesicovaginais e ureterovaginais são complicações incomuns, secundárias a doenças ou a cirurgias pélvicas. O sucesso terapêutico dessas fístulas depende de adequada avaliação pré-operatória para o diagnóstico e visualização do seu trajeto. Este trabalho tem o objetivo de demonstrar o potencial da urorressonância no diagnóstico das fístulas urogenitais e na visualização dos seus trajetos. MATERIAIS E MÉTODOS: Foram analisados, retrospectivamente, os prontuários médicos e as imagens radiológicas e de urorressonância magnética de sete pacientes do sexo feminino com diagnóstico de fístula urogenital. Para a urorressonância foram realizadas seqüências 3D-HASTE com saturação de gordura. RESULTADOS: Seis pacientes apresentavam fístula vesicovaginal e uma paciente tinha diagnóstico de fístula ureterovaginal à direita. Com a utilização da urorressonância magnética, foi possível demonstrar o trajeto da fístula em seis das sete pacientes (85,7%), sem a necessidade de cateterização vesical ou da injeção de contraste. CONCLUSÃO: Este estudo demonstra o potencial e a aplicabilidade da urorressonância na avaliação dessas fístulas.

Renal transplant failure due to urologic complications: Comparison of static fluid with contrast-enhanced magnetic resonance urography

PURPOSE

Postrenal reasons of renal transplant failure can be assessed by magnetic resonance urography. This study was designed to retrospectively compare the diagnostic accuracy of static fluid (T2-)MRU compared to contrast enhanced (CE-)MRU in patients with renal transplant failure.

MATERIAL AND METHODS

Thirty-five consecutive patients (14 female, 21 men; mean age 48.6 years) with renal transplant failure and sonographically detected hydronephrosis were examined both with T2-MRU as well as CE-MRU resulting in 39 MRU examinations. MRU was performed both using T2-weighted HASTE-sequence (T2-MRU) as well as Gadolinium-enhanced 3D-FLASH-sequence (CE-MRU) on a 1.5-T clinical MRI scanner (Magnetom Vision, Siemens Medical Solutions). Subjective image quality of resulting maximum intensity projection was assessed in consensus by two readers blinded to the final diagnosis, using a five point scale. MRU findings were correlated to sonography, operative results or clinical follow up.

RESULTS

CE-MRU yielded a sensitivity of 85.7% (T2-MRU 76.2%), and a specificity of 83.3% (T2-MRU: 73.7%), however statistical significance was not reached. The subjective image quality was significantly better in CE-MRU.

CONCLUSIONS

Only concerning subjective image quality CE-MRU proved superior to T2-MRU. Yet, there was no significant difference in diagnostic accuracy between T2- and CE-MRU. Thinking of incipient nephrogenic systemic fibrosis, T2-MRU can be used as reliable alternative in patients with decreased renal transplant function due to urological complications.

MRI of the kidney-state of the art

Ultrasound and computed tomography (CT) are modalities of first choice in renal imaging. Until now, magnetic resonance imaging (MRI) has mainly been used as a problem-solving technique. MRI has the advantage of superior soft-tissue contrast, which provides a powerful tool in the detection and characterization of renal lesions. The MRI features of common and less common renal lesions are discussed as well as the evaluation of the spread of malignant lesions and preoperative assessment. MR urography technique and applications are discussed as well as the role of MRI in the evaluation of potential kidney donors. Furthermore the advances in functional MRI of the kidney are highlighted.

The Role of Imaging in the Surveillance of Urologic Malignancies

Urologic malignancies are common, accounting for approximately 25% of all new cancer cases in the United States. Patients with urologic malignancies require long-term surveillance to detect progression or recurrence as early as possible. The urologist is faced with the task of balancing patient safety and cost-effectiveness, while finding the most practical follow-up regimen. For each urologic malignancy, this article reviews the commonly used radiologic techniques for surveillance and offers recommended follow-up schedules.