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PubMed2006

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.

Adult↗
PubMed2003

[Magnetic resonance urography as an indicator for surgical treatment of anomalies of the upper urinary tract].

AIMS: To compare the quality of MR of urography with intravenous urography, sonography and scintigraphy of urinary tract, presentation of MR urography as a possible substitution of so far used examinations in preoperation diagnostics of anomalies in upper urinary tract. METHODS: Static MR urography was used to examine 51 patients at the age of one month to 18 years with dilation of upper urinary tract detected by sonography. In 12 of them a dynamic MR study of the kidneys was also performed. Magnetic urography was compared with elimination urography, sonography and dynamic kidney scintigraphy. The detection rate was evaluated within the framework of the complex preoperation examinations for different stages of urinary tract in patients up to 2, 6, 12 and 18 years, respectively. RESULTS: In the total number of 36 kidneys, modified by hydronephrosis, magnetic urography was evaluated as more precise in 18 cases, elimination urography in eight and both examinations were considered equal in 10 cases. The imaging of megaureters by MR urography was more precise in 7 cases, elimination urography was at the same level six times and less precise in eight patients. The results differed in individual age categories. Sonography imaging of the kidney was good as well as for the lower portion of ureter but insufficient for the middle portion. The same course of excretion curves in dynamic excretion urography and dynamic scintigraphy of the kidney was reached in 6 patients. CONCLUSION: MR urography is capable to provide information on anatomy and function of the whole urinary tract in a single examination, being different from excretion urography by its ability of imaging and evaluating the hypofunctional part of the kidney. It represents a possibility to significantly reduce present examination which exerts a load upon the patient.

Adolescent↗
PubMed1998

[RARE urography in pelvic tumors: diagnostic ranking and comparison with intravenous pyelography].

PURPOSE: To examine if RARE urography may replace conventional intravenous urography in patients with suspected urinary obstruction in pelvic tumours. MATERIALS AND METHODS: In a prospective trial on 120 patients with pelvic tumours scheduled for operation, biplanar RARE urography was performed and compared to conventional intravenous urography and ultrasound findings. RESULTS: In 30 out of 120 patients an ureteric obstruction was diagnosed by ultrasound. Sensitivity of RARE urography for obstruction was 98% as compared to 60% in conventional intravenous urography. In 12 patients additional retrograde cystoureterography showed a sensitivity of 83%. Specificity of RARE urography and intravenous urography was 100%. In combination with axial MR tomography RARE urography yielded a more precise localisation of the site of obstruction and the underlying cause (98%) as compared to conventional urography (60%) and ultrasound (56%). CONCLUSION: By use of RARE urography urinary obstruction can be reliably demonstrated or ruled out. Combining RARE urography with tomographic MR imaging allows the precise depiction of the site of the obstruction and may demonstrate the underlying pathology.

Aged↗
PubMed2006

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.

Contrast Media↗
PubMed2004

Diagnostic value of diuretic-enhanced excretory MR urography in patients with obstructive uropathy.

PURPOSE: Ultrasonography and conventional intravenous urography are most common methods in diagnosis of obstructive uropathies. The disadvantage of ultrasonography is inability of visualizing middle and lower one thirds of ureter, while intravenous urography is using radiation, also functionally extra loading effect on kidneys. In this study, the diagnostic value of MR urography on obstructive uropathy were investigated. MATERIALS AND METHODS: Forty five patients who were suffered from obstructive uropathy examined by ultrasonography, intravenous urography and diuretic-enhanced excretory MR urography by using MR-contrast-agent. RESULTS: MR urography established accuracy rate of 92.8% for stone diseases which formed the largest group in this study, however, in other causes of obstructive uropathy, MR urography provide 100% correct diagnosis. CONCLUSION: MR urography provide high quality images for diagnosing and determining causes of urinary obstruction defining position and severity of dilatations as well as showing localization of the pathology. We think that MR urography should be a primary investigation in patients with obstructive uropathy who have contrast agent and X-ray contrindication.

Adolescent↗
PubMed1999

MR urography in the diagnosis of urinary tract obstruction.

OBJECTIVE: To evaluate the efficiency of MR urography in depicting the urinary tract. METHODS: 33 patients with urinary tract abnormalities were additionally evaluated with MR urography. 25 had dilated upper urinary tracts because of urinary obstruction and 8 had normal tracts. MR urography was performed with a 1,5T magnet using a heavy T2w sequence (3D-IR-TSE) in the coronal plane. Images were post-processed using the MIP algorithm. Both reconstructed and source images were evaluated. The results of MR urography were compared with the final diagnosis, which was established surgically in 23 cases, and with multimodality imaging workup in 10 cases. RESULTS: MR urography correctly depicted the level of obstruction and the degree of dilatation of the urinary tract in all 25 patients with hydronephrotic kidneys (sensitivity 100%). Additionally, it succeeded in suggesting the underlying pathology in 25 cases (48%). Concerning the 8 patients without dilatation of the urinary tract, there was either no depiction or depiction was bad. CONCLUSION: MR urography, a new noninvasive technique, demonstrates 100% sensitivity in diagnosing urinary tract obstruction and also suggests the underlying pathology in many cases. In nondilated systems it is not possible to get good images because MR urography only depicts fluid in the urinary tract. Thus we believe that MR urography can provide a reliable alternative in selected cases as opposed to other more invasive modalities, such as retrograde or antegrade urography, and is without the risk of contrast media and radiation exposure.

Adult↗
PubMed2001

MR urography: examination techniques and clinical applications.

Modern MR urography is performed on the basis of two different imaging strategies, which can be used complementarily to cover almost all aspects in the diagnosis of upper urinary tract diseases. The first technique utilizes unenhanced, heavily T2-weighted pulse sequences to obtain static-fluid images of the urinary tract. T2-weighted MR urograms have proved to be excellent in the visualization of the markedly dilated urinary tract, even if the renal excretory function is quiescent. Static-fluid MR urography is less suitable for imaging of disorders that occur in the nondilated collecting system. The second MR urography technique is analogous to the methodology of conventional intravenous pyelography and is, therefore, designated as excretory MR urography. For this purpose, a non-nephrotoxic gadolinium chelate is intravenously administered and after its renal excretion, the gadolinium-enhanced urine is visualized using fast T1-weighted gradient-echo sequences. The combination of gadolinium and low-dose furosemide (5-10 mg) is the key for achieving a uniform distribution of the contrast material inside the entire urinary tract and, secondly, to avoid high endoluminal gadolinium concentrations, which cause signal loss of the urine due to T2* effects. Gadolinium excretory MR urography allows to obtain high-quality images of both nondilated and obstructed urinary tracts in patients with normal or moderately impaired renal function. This article reviews the principles of T2- and T1-weighted MR urography in detail and informs how to use these techniques safely in potential clinical applications such as chronic urolithiasis, intrinsic and extrinsic tumor diseases, and congenital anomalies. Magnetic resonance urography performed in combination with standard MR imaging offers a potential to reduce the need for invasive retrograde pyelography. Although the economic aspect is still problematic, it is obvious that MR urography will continue to increase its role in clinical uroradiology.

Female↗
PubMed1997

Visualization of urinary tract dilatation: value of single-shot MR urography.

The purpose of this study was to evaluate detection of urinary tract dilatation, depiction of obstruction level and determination of cause with single-shot MR imaging in an acquisition time of 2.8 s. Heavily T2-weighted single-shot MR images in 50 patients with ureterohydronephrosis as suspected by ultrasound were prospectively compared with IV urography and clinical outcome. Imaging techniques were obtained within a maximum time interval of 4 h and assessed independently on the same day. Single-shot MR urography was able to demonstrate dilatation and obstruction levels in 96 % of urinary tracts in accordance with X-ray urograms. In 4 patients with a unilaterally negative IV urogram, obstruction levels were demonstrated in single-shot MR urography. Single-shot MR urography did not depict 2 of 7 collecting systems with mild dilatation and contralateral undilated ureters were not adequately visible. Single-shot MR urography consistently visualizes dilated urinary tracts and obstruction levels in moderate and severe dilatation. Single-shot MR urography may be an alternative for IV urography in cases of renal impairment, when iodinated contrast or the application of X-rays is contraindicated, and may help in avoiding direct ureteropyelography. Single-shot MR urography rarely allows determination of the cause of urinary tract dilatation.

Adult↗
PubMed1986

Real-time renal sonography in spinal cord injury patients: prospective comparison with excretory urography.

A prospective blinded comparison of real-time renal sonography and excretory urography was done in 202 urologically asymptomatic patients with spinal cord injury who underwent periodic evaluation. Sonography identified 31 of 31 renal masses (100 per cent) (30 cysts and 1 xanthogranulomatous pyelonephritis), whereas excretory urography identified 14 of 31 masses (45 per cent). Of the 398 kidneys evaluated hydronephrosis owing to an obstructive etiology was noted in 7, all of which (100 per cent) were identified on excretory urography and 6 (86 per cent) were identified on sonography. Only 12 of the 48 kidneys (25 per cent) with typical changes of chronic pyelonephritis on excretory urography were diagnosed correctly by ultrasound. Sonography identified 18 of 23 kidneys (78 per cent) with calculi compared to 20 of 23 (87 per cent) by excretory urography. Although 127 abnormalities were noted in 202 patients, only 21 dictated a change in management. Thirteen abnormalities were visible on a plain film of the kidneys, ureters and bladder (3 kidneys with stones, 1 ureteral stone and 9 bladders with stones). We conclude that sonography and excretory urography are excellent diagnostic modalities for the evaluation of the kidneys. Sonography, plain radiograph of the abdomen and post-contrast injection x-rays on excretory urography frequently offer complementary diagnostic information. The noninvasive nature of ultrasound examination and lack of x-ray exposure combined with no need for special patient preparation make ultrasound examination extremely attractive in this patient population. It is recommended that real-time renal ultrasound and a plain radiograph of the abdomen be used on an alternate basis with excretory urography for the routine followup of spinal cord injury patients.

Adult↗
PubMed2003

Diagnostic value of unenhanced computerized tomography urography in the evaluation of acute renal colic.

This study prospectively evaluated the diagnostic value of unenhanced computerized tomography (CT) urography in patients with acute renal colic. Fifty-nine patients with clinical manifestations of acute renal colic underwent unenhanced helical CT to evaluate urinary tract abnormalities. Reformatted three-dimensional CT urography was performed in all patients. The findings were correlated with ureteroscopy, surgical findings, histopathologic findings, and clinical course. CT urography detected urinary abnormalities in 57 of 59 patients with the clinical manifestation of acute renal colic, including 45 cases of urolithiasis, three urinary malignancies, one congenital abnormality, and eight ureteral strictures (due to chronic inflammation or fibrosis). CT urography showed negative findings in the urinary system in two patients, and after clinical follow-up, urinary abnormality was excluded in these patients. Incidental findings of extrarenal disease were noted in six patients (pulmonary abnormalities, n = 2; gallstones, n = 4). Only one patient with urolithiasis was misdiagnosed as having a renal tumor by CT urography. The sensitivity and specificity of CT urography in diagnosing urolithiasis was 97.8% (44/45) and 100% (14/14), respectively. Three-dimensional CT urography is a newly developed modality to evaluate anomalies of the urinary tract. The highly accurate diagnostic value of CT urography makes it a suitable alternative or substitutive modality in patients with acute flank pain.

Acute Disease↗
PubMedDate not supplied

CT urography in the evaluation of urinary tract disease.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of using limited CT through the kidneys following excretory urography in selected situations. MATERIALS AND METHODS: Within 2 h of excretory urography 568 patients had add-on CT without using additional contrast medium. In 487 patients with hematuria the results of the combined studies were compared with blinded prospective interpretations of each. In addition 81 patients had add-on CT for specific urographic questions. RESULTS: Of the 345 renal parenchymal masses seen on CT in both groups, only 185 were detected prospectively on excretory urography. For the 81 patients who had CT because of abnormalities seen on excretory urography, including 54 with pseudotumors, findings were clarified and the correct diagnosis made. In 27 of 30 patients with lesions in the collecting system the lesions were detected only on excretory urography. CONCLUSION: Excretory urography followed by limited CT increases the diagnostic accuracy for detecting, characterizing, or ruling out urinary tract disease by combining the high sensitivity of traditional excretory urography for detecting lesions in the collecting system and ureter with the high accuracy of CT for parenchymal and perinephric lesions without an additional patient visit or additional contrast medium. Because it leaves so few unanswered questions, the combination of standard excretory urography and limited CT is an excellent screening study in selected situations. It can be performed quickly, at controlled cost, is highly accurate, and is convenient for the patient, the referring physician, and the examining department.

Adolescent↗
PubMed2002

Patients with acute flank pain: comparison of MR urography with unenhanced helical CT.

PURPOSE: To compare unenhanced helical computed tomography (CT) and magnetic resonance (MR) urography, by using T2-weighted and contrast material-enhanced T1-weighted imaging to examine patients with acute flank pain, with reference to excretory urography and final clinical diagnosis. MATERIALS AND METHODS: Forty-nine patients underwent CT, MR urography (with T2-weighted and gadopentetate dimeglumine-enhanced T1-weighted sequences), and excretory urography. CT and MR urographic findings were evaluated separately and independently by two radiologists each (CT, observers A and B; MR urography, observers C and D) for the presence, cause, level, and degree of obstruction. The final conclusive diagnosis was based on the combination of excretory urographic, clinical, and interventional results. RESULTS: At final diagnosis, 32 (65%) patients were found to have ureteral stones causing unilateral obstruction. In ureteral stone detection, the sensitivity and specificity of CT were 90.6% (29 of 32 patients) and 100.0% (17 of 17 patients), respectively (observer A) and 90.6% (29 of 32 patients) and 94.1% (16 of 17 patients), respectively (observer B), while those of MR urography were 93.8% (30 of 32 patients) and 100.0% (17 of 17 patients), respectively (observer C) and 100.0% (32 of 32 patients) and 100.0% (17 of 17 patients), respectively (observer D). Spearman correlation coefficients for stone size at CT were 0.76 (P <.001) and 0.75 (P <.001) and at MR urography, 0.49 (P =.005) and 0.51 (P =.004). CONCLUSION: In routine clinical practice, CT is the modality of choice in the evaluation of patients with acute flank pain. MR urography is an accurate and suitable alternative imaging technique in selected patients.

Acute Disease↗
PubMed2002

Functional and morphologic evaluation of congenital urinary tract dilatation by using combined static-dynamic MR urography: findings in kidneys with a single collecting system.

PURPOSE: To assess combined static-dynamic magnetic resonance (MR) urography in the evaluation of congenital urinary tract dilatation in infants and children. MATERIALS AND METHODS: Sixty-two patients with urinary tract dilatation underwent prospective examination with combined static-dynamic MR urography. A combination examination involved use of a static T2-weighted three-dimensional inversion-recovery fast spin-echo sequence and a dynamic T1-weighted two-dimensional fast field-echo sequence with gadopentetate dimeglumine-DTPA and furosemide application. Twelve additional patients underwent examination with only static MR urography. Thus, both image quality and morphologic features were assessed in 74 patients with the use of MR urography. The results were compared with those of ultrasonography and, when available, conventional urography or surgery. In 62 patients, the dynamic sequence was used to calculate split renal function from renograms generated from parenchymal regions of interest and to assess urinary excretion from whole-kidney renograms. Results were compared with those of diuretic renal scintigraphy (DRS) for split function (Spearman rank correlation coefficient) and urinary excretion (kappa coefficient). RESULTS: Stenoses at the ureteropelvic (n = 33) and ureterovesical (n = 31) junctions and within the ureter (n = 3) and nonstenotic dilatation (n = 23) were clearly depicted, while the normal urinary tract (n = 51) was depicted in its entirety in 47 of 51 examinations. Image quality was considered good or excellent in 95% of the kidney-ureter units. For split renal function, dynamic MR urography and DRS showed significant correlation (r = 0.92, P <.001). For urinary excretion, MR urography and DRS showed strong agreement (kappa = 0.67), with concordant classification of urinary excretion in 59 (81%) of 73 abnormal kidney-ureter units and in all 47 (100%) normal kidney-ureter units. CONCLUSION: Combined static-dynamic MR urography provides high-quality depiction of the urinary tract in infants and children, while allowing accurate determination of single-kidney function and reliable evaluation of urinary excretion.

Child↗
PubMed1996

MR urography using HASTE imaging in the assessment of ureteric obstruction.

OBJECTIVE: The purpose of this study was to evaluate an MR sequence using half-Fourier acquisition single-shot turbo spin-echo (HASTE) imaging in the assessment of ureteric obstruction. SUBJECTS AND METHODS: We prospectively evaluated 111 kidneys in 56 consecutive patients with HASTE MR urography and compared that imaging technique with excretory urography. The HASTE sequence was used to acquire images in the axial, sagittal, and coronal planes while patients held their breath. Level of obstruction and ureteric diameter were assessed, and the time required to determine the level of obstruction by both techniques was noted. RESULTS: With HASTE MR urography, we correctly diagnosed obstruction in 41 (100%) of 41 kidneys. Of the obstructed kidneys in which the ureter was shown by both excretory urography and MR urography, agreement was high (kappa = .642) between the two imaging techniques regarding the level of obstruction. HASTE MR urography showed perirenal fluid in 20 (87%) of 23 acutely obstructed kidneys. HASTE MR urography showed the site of obstruction on the first 13-sec scan in 33 (80%) of 41 kidneys. CONCLUSION: HASTE MR urography accurately and rapidly shows the level and degree of ureteric obstruction. It can be used to differentiate between acute and chronic obstruction on the basis of its ability to show perirenal fluid.

Acute Disease↗
PubMed2004

Potential impact of pediatric MR urography on the imaging algorithm in patients with a functional single kidney.

OBJECTIVE: The purpose of this study was to evaluate the potential of MR urography in the assessment of children with a suspected "functional single kidney." SUBJECTS AND METHODS: Sixty patients (age range, 2.7 weeks to 15.7 years) who had been referred for assessment of a suspected functional single kidney underwent MR urography in addition to detailed sonography of the urinary tract and the currently indicated standard imaging. The results of the conventional imaging ((99m)Tc-dimer captosuccinic acid scintigraphy, voiding cystourethrography, and genitography) were compared with the results of sonography and MR urography; surgical findings served as the gold standard if available. RESULTS: Twenty-six patients had a single kidney. The other diagnoses were six contralateral multicystic dysplastic kidneys, two normal ectopic kidneys, one crossfused double system, and 25 ectopic or dysplastic renal buds. Scintigraphy detected all normal kidneys, two ectopic kidneys, and two dysplastic renal buds. Detailed sonography missed two ectopic kidneys and two orthotopic dysplastic renal buds, but one additional renal bud that could not be confirmed on other imaging techniques (accuracy, 91.7%; sensitivity, 88.2%; specificity, 96.2%) was suspected. MR urography results were correct in all patients and verified in all 13 with surgical correlation. CONCLUSION: MR urography allows a reliable assessment of renal and ureteral anatomy and of dysplastic or ectopic renal buds, even in non- or poorly functioning systems. MR urography therefore has the potential to replace the currently used excretory urography and scintigraphy. In patients with a suspected functional single kidney a detailed sonographic study and MR urography should be considered the diagnostic algorithm of choice.

Adolescent↗
PubMedDate not supplied

[An evaluation of orthotopic ileal neobladders by dynamic digital urography].

PURPOSE: To report on the diagnostic capabilities of dynamic digital urography in the evaluation of orthotopic ileal neobladders. MATERIAL AND METHODS: Ten male patients (aged 61.3 +/- 14.7 years) with orthotopic ileal neobladder (4 Studer, 4 Camey type II with spiralized ileal segment and 2 classic Camey type II) underwent dynamic digital urography using an angiographic unit (Philips DVI/ARC-A). Eight patients were asymptomatic and two presented mild nycturia. All patients should have undergone follow-up conventional urography, which was replaced, for the purposes of our study, by dynamic digital urography. The intestinal cleansing regimen usual for the double contrast barium enema was used in all the patients. Ninety mL of a nonionic iodinated contrast agent were administered i.v. with an automatic injector. After precontrast mask images, two postcontrast sequences were acquired 15 s and 30 min after the injection (each made of 20 images acquired every 10 seconds). Postprocessing consisted of digital image subtraction and videorecording. RESULTS: Renal pelvis and calyceal systems were well visualized in 18/20 excretory systems. Eighteen of 20 ureters were visualized completely up to the ureteral jet, and two were only partially visualized. Calyceal, pyelic and ureteral enlargement with ureteral kinking were observed in a patient with classic Camey type II. High motility was seen in 11 ureters, moderate in 5 and mild in 4. The orthotopic ileal neobladder was well opacified in 8/10 patients. Effective peristalsis of the afferent ileal segment was seen in all the Studer type neobladders. Ureteral reflux was not observed in any patient. DISCUSSION: After orthotopic ileal neobladder reconstruction, the most frequent complications include urinary leakage, intestinal obstruction, venous thrombosis, stenosis of the neobladder anastomoses, incontinence, cancer recurrence, stone formation. In the follow-up, many diagnostic tools are used: intravenous urography, retrograde cystography, urodynamic studies, transabdominal and transrectal ultrasonography. With dynamic digital urography the nephrographic evaluation was possible in all patients, as well as the evaluation of calyceal, pyelic and ureteral opacification and even ureteral peristalsis. Moreover, this diagnostic tool allows the morphofunctional dynamic study of the ureteral-neobladder anastomoses and of the orthotopic ileal neobladder, even evaluating the residual peristalsis of the detubularized ileal segment. A major drawback of the new method is the relatively high radiation dose given to the patient. A limitation of the study is the selection of a population of completely or nearly asymptomatic patients. CONCLUSIONS: Dynamic digital urography provides useful morphologic and functional information in the follow-up of patients with orthotopic ileal neobladder and could replace conventional urography in symptomatic patients.

Aged↗
PubMedDate not supplied

Multidetector CT-urography in the study of urological complications in renal transplant.

PURPOSE: To evaluate the value of CT-urography in the diagnosis and follow-up of the urological complications of renal transplantation. MATERIALS AND METHODS: We performed 19 CT-urography examinations (3 of which were follow-up) on 15 patients by using a spiral multislice CT scanner and multiplanar reconstructions. The examinations were carried out directly after administration of 100 ml of iodinated contrast medium by slow iv infusion, with acquisitions starting 5 minutes after the end of the infusion. Surgery was regarded as the gold standard for the diagnosis of urological complications in the operated patients, whereas in patients who had undergone medical therapy or stent placement the gold standard was 1 month ultrasound and clinical follow-up with evaluation of diuresis and renal function. RESULTS: Between January 1999 and December 2001 a total of 210 kidney transplantations were performed at our hospital. There were 34 urological complications in 28 patients with a 16.1% prevalence, consistent with the major international studies. The complications detected were 14 urine leaks and 19 ureteral obstructions secondary to stones, oedema, blood clots and stricture. We observed one case of reflux in the allograft ureter. Fourteen out of 16 CT-urography examinations yielded important clues for the diagnosis of urological complications in kidney allografts, completely replacing standard urography. In particular, CT-urography correctly detected 5 urinary fistulas by demonstrating iodinated contrast material leaks along the ureteral tract, and 8 cases of obstructive uropathy due to different causes (1 submucosal tunnel edema, 1 blood clot, 1 stone and 5 cases of ureteral stricture). One case of urinary fistula and one of obstructive uropathy were not detected. DISCUSSION AND CONCLUSIONS: CT-urography proved to be an important diagnostic tool in the evaluation of urological complications of kidney allografts, showing a diagnostic accuracy over 90%; it is useful for confirming the type and site of urological lesions, and therefore to provide guidance for a targeted surgical approach. Compared with excretory urography, which is no longer used in this diagnostic field, CT-urography is more complete and precise as it provides information not only about the urinary tract, but also about the kidney parenchyma and pararenal fluid collections. The only disadvantage, which limits its use to selected cases, is the risk associated with the use of iodinated contrast agents in patients with impaired renal function.

Contrast Media↗
PubMed2000

Spinal dysraphism at MR urography: initial experience.

PURPOSE: To prospectively evaluate the role of magnetic resonance (MR) urography in the radiologic assessment of patients with spinal dysraphism. MATERIALS AND METHODS: Fourteen patients with spinal dysraphism were referred for MR urography with half-Fourier rapid acquisition with relaxation enhancement (RARE) (repetition time msec/echo time msec = 11.9/95) and RARE (2,800/1,100) sequences on a 1.5-T MR machine. Six patients did not tolerate MR urography owing to claustrophobia (n = 4) or flexion deformities (n = 2), giving a final success rate of 57% (eight patients). Two patients had a single kidney (one after nephrectomy, one with a crossed-fused ectopic kidney). Images were jointly assessed by two radiologists and compared with excretory urographic studies. The signal intensity ratio and contrast-to-noise ratio were also calculated. RESULTS: Visualization of the kidneys, pelvicaliceal system, and ureters was better with half-Fourier RARE than with RARE imaging, whereas visualization of the bladder was comparable with both sequences. The mean signal intensity ratios for half-Fourier RARE and RARE sequences, respectively, were 16.2 +/- 3.65 and 19.2 +/- 3.65 (P =. 58, factorial analysis of variance model), whereas the mean contrast-to-noise ratios were 55.4 +/- 5.16 and 47.8 +/- 5.16 (P =. 34). Cortical scarring was depicted more clearly at MR urography than at excretory urography, whereas a renal calculus seen at excretory urography was not detected at MR urography. CONCLUSION: MR urography was feasible in 57% of patients with spinal dysraphism and is a safe, accurate method of evaluating the upper urinary tract.

Adolescent↗