Multi-Detector row CT urography on a 16-row CT scanner in the ...

Eur Radiol 

DOI 10.1007/s00330-006-0383-2 

UROGENITAL 

A. C. Tsili 

S. C. Efremidis 

J. Kalef-Ezra 

D. Giannakis 

Y. Alamanos 

N. Sofikitis 

C. Tsampoulas 

<strong>Multi</strong>-<strong>Detector</strong> <strong>row</strong> <strong>CT</strong> <strong>urography</strong> on a 16-<strong>row</strong> 

<strong>CT</strong> scanner in the evaluation of urothelial 

tumors 

Received: 15 August 2005 

Revised: 31 May 2006 

Accepted: 23 June 2006 

# Springer-Verlag 2006 

A. C. Tsili . S. C. Efremidis . 

C. Tsampoulas 

Department of Clinical Radiology, 

University Hospital of Ioannina, 

Platia Pargis, 2, 

453 32 Ioannina, Greece 

J. Kalef-Ezra 

Department of Medical Physics, 




D. Giannakis . N. Sofikitis 

Department of Urology, 




Y. Alamanos 

Department of Hygiene and Public Health, 




A. C. Tsili (*) 

Medical School, 

University of Ioannina, 

Leoforos Panepistimiou, 


e-mail: a_tsili@yahoo.gr 

Tel.: +30-2651070708 

Fax: +30-2651097862 

Abstract The purpose of this study 

was to assess the role of multi-detector 

<strong>row</strong> <strong>CT</strong> <strong>urography</strong> (MD<strong>CT</strong>U), on a 

16-<strong>row</strong> <strong>CT</strong> scanner in the evaluation 

of patients with painless hematuria, 

with emphasis placed in the detection 

of urothelial tumors. We retrospectively 

reviewed the MD<strong>CT</strong> urographies 

of 75 patients, referred for 

painless hematuria. The <strong>CT</strong> protocol 

included unenhanced images, 

obtained with a detector configuration 

of 16×1.5 mm and pitch of 1.2, 

nephrographic and excretory-phase 

images, obtained with a detector collimation 

of 16×0.75 mm and pitch of 

1.2. Axial and coronal reformatted 

images were evaluated. Three-dimensional 

reformation of the excretoryphase 

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 MD<strong>CT</strong>U; 

the most common cause was urothelial 

cancer, including seven tumors with a 

diameter equal or smaller than 0.5 cm 

in diameter. Sixteen-<strong>row</strong> MD<strong>CT</strong>U 

provided satisfactory results in the 

investigation of patients with painless 

hematuria. The main advantage of the 

technique is its ability to detect 

uroepithelial malignancies. 

Keywords Computed tomography . 

Urinary tract . Hematuria . 

Transitional cell carcinoma 

Introduction 

<strong>Multi</strong>-detector <strong>row</strong> <strong>CT</strong> <strong>urography</strong> (MD<strong>CT</strong>U) is progressively 

becoming a powerful tool in the evaluation of the 

urinary tract in patients with painless hematuria [1–5]. <strong>CT</strong> 

is widely accepted as the examination of choice for patients 

with renal colic [6, 7]. The introduction of multi-detector 

<strong>row</strong> <strong>CT</strong> scanners provided a highly accurate evaluation 

of renal masses, as well as staging of renal malignancies 

[8, 9]. With the use of 4-detector or 8-detector <strong>row</strong> <strong>CT</strong> 

scanners, <strong>CT</strong> <strong>urography</strong> demonstrated satisfactory results 

compared with IVU in the evaluation of abnormalities 

involving the urothelium [10–13]. Raptopoulos et al. 

showed a significantly improved visualization of pelvicaliceal 

details with MD<strong>CT</strong>U [14]. However, the sensitivity 

of MD<strong>CT</strong>U in the detection of uroepithelial malignancies, 

especially tumors of small size need to be further evaluated 

[15].

With the introduction of 16-<strong>row</strong> <strong>CT</strong> scanners, the 

radiologic evaluation of the urinary tract is changing 

rapidly. The advantages of a 16-<strong>row</strong> <strong>CT</strong> scanner are the 

following: fast scanning (coverage of at least 48 mm long 

body sections per second), acquisition of thin collimation 

and creation of high-resolution multiplanar and threedimensional 

(3D) reformatted images, with excellent 

anatomic details [16, 17]. The purpose of our study was 

to assess the role of multi-detector <strong>row</strong> <strong>CT</strong> <strong>urography</strong>, 

using a 16-<strong>row</strong> <strong>CT</strong> scanner in the evaluation of patients 

presenting with painless hematuria, with emphasis placed 

in the detection of urothelial tumors. 

Materials and methods 

This study was a retrospective review of <strong>CT</strong> urographies 

performed on a 16-<strong>row</strong> <strong>CT</strong> scanner for the evaluation of 

painless hematuria. The study included 75 consecutive 

patients (47 men and 28 women) with a mean age of 63 

years (age range: 21–87 years), who underwent multidetector 

<strong>row</strong> <strong>CT</strong> <strong>urography</strong> between March 2004 and 

January 2005, referred to the department of Radiology for 

painless hematuria. Five patients were younger than 40 

years old. Informed consent for this study was obtained 

from each patient. 

The clinical evaluation of the patients included a careful 

history and clinical examination. The laboratory analysis 

began with a comprehensive examination of the urine and 

urine sediment and cytologic analysis. All patients had an 

ultrasound examination of the abdomen, some performed 

at an outpatient clinic and the rest at our department. 

Patients with hematuria and a sonographic examination 

demonstrating a kidney mass were not included in this 

study, since they were evaluated with a different protocol 

tailored for the investigation of renal masses. Cystoscopic 

examination was carried out in all patients. 

In patients in whom clinical and imaging evaluation 

revealed no cause for the hematuria, a follow-up was 

recommended. This included the repeat of the urinary 

analysis and urine cytology every month for the first 4 

months and thereafter at 6, 12, 24 and 36 months. 

Immediate reevaluation with repeat of the <strong>CT</strong> examination 

and/or cystoscopy and urine cytology was recommended if 

any of the following occurred: development of gross 

hematuria, abnormal urinary cytologic findings or irritating 

voiding symptoms in the absence of infection [18]. 

Technique 

Examinations were performed on a 16-<strong>row</strong> <strong>CT</strong> scanner 

with 24 mm scanning span per rotation (Mx8000 IDT, 

Philips) and a three-phase protocol was used. Unenhanced 

images were obtained from the kidneys through the urinary 

bladder using a slice collimation of 16×1.5 mm and a slice 

thickness of 3 mm. These images were scrutinized to 

identify urinary tract calculi or calcifications, as well as to 

assist in the characterization of any detected renal masses. 

Intravenous non-ionic iodinated contrast material (120 ml, 

320 mg I/ml) was subsequently administered at a rate of 

3 ml/sec, via mechanical injector, followed by 250 ml of 

normal saline 0.9%, rapidly infused by intravenous drip. 

The second phase was the nephrographic phase obtained at 

100 sec delay, covering the area from the diaphragm to the 

iliac crests and the third phase was the excretory phase 

starting with 10-minute delay, covering the kidneys, ureters 

and the urinary bladder. The nephrographic phase was 

chosen for the detection and characterization of renal 

masses, as well as for staging, while the excretory phase 

was utilized for the evaluation of abnormalities involving 

the urothelium. For these two phases a section collimation 

of 16×0.75 mm and a slice thickness of 1 mm were 

employed. The nephrographic and excretory phase images 

were reconstructed at 0.5 mm intervals (50% overlap). All 

the scans were performed with a pitch of 1.2, at 120 kV, 

using a rotation time of 0.5 sec. Both dose modulation 

(DOM) and automatic current setting (DoseRight) were 

used [19]. No oral contrast material was given, in order to 

facilitate 3D reformatting. The entire <strong>CT</strong> <strong>urography</strong> 

examination lasted 15 minutes per patient on the average 

and every scan lasted 7–12 seconds on the average. Our <strong>CT</strong> 

protocol is illustrated on Table 1. 

<strong>CT</strong> data interpretation 

Image interpretation was done on a workstation (MxView, 

Philips) and included the study of the axial images of the 

unenhanced scan. The evaluation of the axial source 

images of the nephrographic and the excretory phase was 

Table 1 <strong>CT</strong> protocol for the investigation of hematuria 

Unenhanced 

scan 

Nephrographic 

phase, 

100 sec 

Excretory 

phase, 

10 min 

kV, rotation time (sec) 120/0.5 120/0.5 120/0.5 

mAsnom/mAssel 200/170 200/175 200/160 

<strong>Detector</strong> collimation 16×1.5 16×0.75 16×0.75 

(mm) 

Pitch 1.2 1.2 1.2 

Slice thickness (mm) 3 1 1 

Reconstruction 3 0.5 0.5 

interval (mm) 

Area 

Kidneysurinary 

bladder 

Diaphragmiliac 

crests 

Kidneysurinary 

bladder 

Contrast material 

(iv) 

120 ml (320), 3 ml/sec and 250 ml 

saline 0.9%

difficult, due to the large number (approximately 400–800) 

of noisy images. For these reasons reformatted images, of 

4 mm slice thickness and at 3 mm intervals, usually in the 

transverse and coronal planes (using the Extended 

Brilliance V.1.0.1.1. software) were used for interpretation 

of the nephrographic and excretory phases. The time to 

generate these images was less than one minute. Wide 

window settings (bone window settings, W: 1500, L: 500) 

were also used for the excretory phase, to better visualize 

caliceal details, as well as filling defects in the urinary 

collecting system (Fig. 1). Finally, three-dimensional (3D) 

reconstructions of the excretory phase data were performed, 

using the volume rendering technique and the 

same software, obtained in the coronal and/or oblique 

planes. Volume rendering technique was considered ideal 

for the creation of the 3D reconstructions [3], especially 

because it does not obscure superimposed structures, such 

as the pelvis and the ureters. The time required to create the 

3D reformatted images was less than one minute. The main 

advantage of these images was that they were more familiar 

to our clinical colleagues, because they closely resemble 

those of intravenous <strong>urography</strong>. Additionally, these images 

could be more effectively used for preoperative planning, 

whenever it was necessary. 

An important issue on <strong>CT</strong> <strong>urography</strong> is the degree of 

ureteral opacification. In cases, where excretion of the 

contrast material was detected on <strong>CT</strong> <strong>urography</strong>, the extent 

of ureteral opacification was evaluated. The ureter was 

divided into proximal, middle and distal thirds. The 

proximal third was defined as the portion of the ureter 

that extended from the renal pelvis to the superior iliac 

crests. The middle third was defined as the portion of the 

ureter between the superior iliac crests and the anterior 

inferior iliac spines. The lower third was defined as the 

segment of the ureter located between the anterior inferior 

iliac spines and the ureterovesical junction. An opacification 

score from 1 to 3 was assigned for each ureter based on 

the length of the ureteral portion opacified. A score of 1 

indicated opacification of less than one third of the ureter; a 

score of 2 indicated opacification of less than two thirds of 

the ureter; a score of 3, opacification of more than two 

thirds of the ureteral segments up to the entire length of the 

ureter. 

<strong>CT</strong> data correlation 

Findings of MD<strong>CT</strong>U were retrospectively correlated with 

the results of clinical and imaging follow-up, cystoscopy 

and/or ureteroscopy, as well as with surgical and histological 

findings, in surgical cases. More specifically, in 

patients with urinary tract lithiasis confirmation of the <strong>CT</strong> 

diagnosis was documented on the basis of other imaging 

examinations (plain films and ultrasound). Conventional 

cystoscopy and histologic results were used as standard of 

reference in patients with urinary bladder carcinomas. 

Conventional cystoscopy was also used to confirm the 

presence of benign prostatic hyperplasia (BPH) as the 

cause of hematuria. In patients with transitional cell 

carcinoma of the pelvicaliceal system, as well as ureteral 

lesions, confirmation of the <strong>CT</strong> diagnosis was obtained 

based on other imaging examinations (IVU, retrograde 

pyelography), ureteroscopic findings and finally the surgical 

and histologic findings. Surgery and histologic diagnosis 

confirmed the presence of other malignancies (renal 

cancer, pancreatic and prostate cancer). For patients with 

urinary tract congenital anomalies, the findings of IVU 

were used for confirming the <strong>CT</strong> diagnosis. 

The <strong>CT</strong> images were interpreted by one radiologist 

(A. C. T), blinded to the results of the other examinations. 

Dosimetry 

For dosimetry the free-in-air Computed Tomography Dose 

Index was measured along the axis of rotation using a 

pencil-shaped ion chamber, type 10×5 10.3 <strong>CT</strong> (Radcal 

Corp., California, USA). The effective dose was calculated 

using the ImPA<strong>CT</strong> <strong>CT</strong> Patient Dosimetry Calculator 

(version 0.99v) [20]. The software used is based on the 

Fig. 1 A 70-year-old woman 

with fibroepithelial polyp of the 

right ureter. Coronal (a) and 

transverse (b) reformatted 

images of the excretory phase 

demonstrate an elongated filling 

defect (ar<strong>row</strong>), smoothly marginated, 

involving the intravesical 

part of the right ureter and 

prolapsing into the urinary 

bladder. The lesion is clearly 

seen with bone window settings

Table 2 MD<strong>CT</strong>U diagnoses for the hematuria 

<strong>CT</strong> diagnoses 

Number of patients 

Stone disease 

Ureter 4 

Kidney 7 

Urinary bladder 2 

Passed stone 1 

Cancer 

Urinary bladder 16 

Kidney 7 

Ureter 1 

Prostate 1 

Pancreas 1 

Benign tumors 

Kidney 1 

Ureter 1 

Urinary tract inflammation 2 

Benign prostatic hyperplasia 9 

Pyeloureteric junction obstruction 1 

Congenital anomalies 4 

Monte Carlo conversion coefficients obtained by Jones and 

Shrimpton [21]. Considering the fact that the tube current is 

modulated across the patient’s body, based on planning 

scan projection radiograph (PSPR) and body asymmetry 

(dose modulation function), the mean mAs per rotation at 

each phase for each individual patient was recorded and the 

mean mAs per rotation among all patients at each phase 

was calculated. To assess the probability for induction of 

deterministic effects, two groups of LiF:Mg,Ti thermoluminescent 

dosimeters were fixed with hypo-allergic tape 

on the skin at the abdomen of six consecutive patients, over 

a two-week period (one group at umbilicus and the other at 

midaxillary line in the same level). 

Results 

In 18 of 75 patients (24%) no urinary tract abnormality was 

seen on MD<strong>CT</strong>U. In 16 of these patients the clinical 

evaluation, including cystoscopy and urinalysis revealed 

no cause for the hematuria. These cases have been 

followed-up for a period ranged from 12 to 20 months 

and remained negative. These cases were considered as 

true-negative. We had two false-negative cases. One with a 

patient, in whom the hematuria was attributed to carcinoma 

of the prostate gland, not shown on MD<strong>CT</strong>U and a second 

case, in which the urinary bladder was filled with blood 

clots. In this case it was impossible for the <strong>CT</strong> examination 

to recognize a small tumor, with a diameter less than 

0.5 cm, as seen with conventional cystoscopy. This tumor 

could probably be detected, if there were no blood clots on 

the urinary bladder during <strong>CT</strong> scanning, as it was detected 

on sonography. This lesion was characterized as transitional 

cell carcinoma (TCC) on histology. 

In 57 of 75 patients (76%) the cause of hematuria was 

identified. Table 2 demonstrates the different etiologies of 

hematuria, as shown on MD<strong>CT</strong>U. 

In 12 patients, the cause of hematuria was urinary tract 

lithiasis. Four patients had ureteral stones, ranging from 3.5 

to 7 mm in diameter, with no signs of obstruction in three. 

These four patients were followed-up with plain films and 

ultrasound. In one patient renal calculi were also seen. In 

six patients the calculi were located in the pelvicaliceal 

system, confirmed also on plain films and sonography and 

in two in the urinary bladder, confirmed by cystoscopy. In 

six of these cases urinary tract lithiasis was detected as the 

only possible cause for the hematuria, since both MD<strong>CT</strong>U 

and clinical evaluation revealed no other cause. In the other 

six patients BPH was also detected on <strong>CT</strong>U, but 

conventional cystoscopy did not confirm this finding as 

the cause for the hematuria. In one additional patient only 

signs of obstruction were detected, probably due to a 

Fig. 2 A 67-year old man 

with TCCs of the urinary 

bladder, the larger tumor 

extending into the perivesical 

space. (a) Coronal and 

sagittal (b) reformations of 

the excretory phase show a 

small polypoid lesion (short 

ar<strong>row</strong>) of the urinary bladder 

wall and a larger tumor (long 

ar<strong>row</strong>) extending into the 

perivesical fat

Fig. 3 A 73-year old man with TCC of the urinary bladder with 

involvement of the perivesical fat. (a, b) Coronal reformatted images 

of the excretory phase show left hydronephrosis and ureteral 

dilatation. A mass involving the left lateral wall of the urinary 

passed stone, as it was indicated by his past history of renal 

colic. 

In 16 patients MD<strong>CT</strong>U demonstrated carcinoma of the 

urinary bladder. There were two false-positive cases. In one 

case a small tumor of the urinary bladder seen on MD<strong>CT</strong>U 

was not confirmed by cystoscopy and was considered to 

represent a blood clot. In the second case, <strong>CT</strong> <strong>urography</strong> 

showed thickening of the right anterolateral wall of the 

urinary bladder, as well as enhancement after contrast 

material administration. The patient underwent conventional 

cystoscopy and no abnormality of the urinary 

bladder wall was seen. In 14 patients MD<strong>CT</strong>U detected 

bladder with perivesical fat infiltration is detected. (c) Threedimensional 

VR image confirms the presence of the urinary bladder 

mass, as well as the findings of urinary tract obstruction 

20 urinary bladder tumors, confirmed at conventional 

cystoscopy, of these patients three had multiple lesions 

(one had two lesions, one three and one four lesions), 

(Fig. 2). Histologic examination demonstrated TCCs in 12 

patients and undifferentiated carcinoma of the urinary 

bladder in one case, with involvement of the perivesical fat. 

In two patients with TCCs the tumor infiltrated the 

perivesical fat (Fig. 3), while in one patient there was 

Fig. 4 A 69-year old man with TCC of the urinary bladder. 

Transverse reformatted image of the excretory phase shows a sessile 

mass (ar<strong>row</strong>) of the left anterolateral wall of the urinary bladder. In 

this patient the first conventional cystoscopy was negative and the 

lesion was confirmed on a repeat examination 

Fig. 5 A 69-year old man with transitional cell carcinoma of the 

urinary bladder. Sagittal reformatted image of the excretory phase 

shows a small polypoid lesion (ar<strong>row</strong>) of posterior wall of the 

urinary bladder. The lesion was seen only on sagittal reformations

Fig. 6 A 62-year old man with TCC of the renal pelvis. (a) 

Transverse unenhanced image shows a soft-tissue mass (ar<strong>row</strong>) of 

the right renal pelvis. (b) Transverse reformatted image of the 

nephrographic phase demonstrates enhancement of the mass 

Fig. 7 A 65-year old woman with TCC of the right renal collecting 

system. Sagittal reformation of the excretory phase depicts a mass 

(ar<strong>row</strong>) involving the lower calyx 

(ar<strong>row</strong>). (c) Coronal reformatted image of the excretory phase 

shows the lesion as a filling defect with irregular margins, involving 

the right renal pelvis (ar<strong>row</strong>) 

metastatic involvement of the retroperitoneal lymph nodes, 

shown by MD<strong>CT</strong>U. In a third patient with TCC the tumor 

infiltrated the retrovesical fat and there was also retroperitoneal 

lymhadenopathy. This patient had a previous 

hysterectomy, performed at an outpatient clinic, reported 

for benign causes. Finally in one patient conventional 

cystoscopy was negative, while MD<strong>CT</strong>U showed a sessile 

mass of the urinary bladder wall (Fig. 4). The patient 

underwent a second cystoscopy, which confirmed the <strong>CT</strong> 

findings and histology revealed a TCC. The size of urinary 

bladder carcinomas detected on MD<strong>CT</strong>U ranged from 0.4 

to 7 cm in diameter (mean size: 1.8 cm), included were six 

lesions with a diameter equal or smaller than 0.5 cm, 

(Fig. 5). 

In six patients carcinoma was located in the pelvicaliceal 

system, characterized as TCCs histologically (Figs. 6, 7)in 

five, and as TCC, with sarcomatous elements in one patient 

(Fig. 8). These lesions measured 0.7–5 cm in maximal 

diameter (mean diameter: 2 cm). In two more patients 

MD<strong>CT</strong>U revealed a ureteral lesion, measuring 0.3 cm in 

transverse diameter, proved histologically to be a TCC in 

one patient (Fig. 9) and a fibroepithelial polyp, involving 

Fig. 8 A 68-year old man with 

TCC of the left renal collecting 

system with sarcomatous 

elements, which invades renal 

parenchyma. (a) Transverse 

reformation of the nephrographic 

phase depicts a left atrophic 

kidney with a mass (ar<strong>row</strong>) 

involving the lower calyx and 

invading renal parenchyma. The 

patient underwent left nephrectomy 

and ureterectomy. Six 

months later, local recurrence 

and retroperitoneal lymphadenopathy 

was detected on a 

follow-up <strong>CT</strong> examination (b)

Fig. 9 A 70-year old man with TCC of the right ureter. Coronal 

reformatted image of the excretory phase demonstrates a mass 

(ar<strong>row</strong>s) involving part of the upper and middle third of the right 

ureter. The lesion causes dilatation of the right ureter, as well as right 

hydronephrosis and delay of the excretion from the right kidney 

the intravesical part of the ureter (Fig. 1) in the other. In the 

last case, the lesion mainly detected with wide window 

settings, measured 0.2 cm in transverse diameter and did 

not cause ureteral dilatation. 

In three patients renal cell carcinoma, pancreatic cancer 

and carcinoma of the prostate gland were the causes of 

hematuria, respectively. The first patient was presented 

with a kidney mass, metastatic to the retroperitoneal lymph 

nodes and liver and the second patient with a carcinoma of 

the pancreatic tail infiltrating the left adrenal gland, the 

perinephric space and the left renal pelvis. In these cases 

the diagnosis was confirmed histologically following 

diagnostic laparotomy in two and by biopsy of the prostate 

gland in the third patient. 

Benign prostatic hyperplasia was the cause of hematuria 

in nine patients, confirmed by conventional cystoscopy, 

seven of them had surgery and the other two were 

followed-up for at least one year under medical treatment. 

Urinary tract inflection was detected as the cause of 

hematuria in two patients, a case of acute pyelonephritis 

and a case of cystitis, proved by the clinical and laboratory 

data. 

Congenital anomalies identified on MD<strong>CT</strong>U such as 

pelvic kidney, two partial ureteral duplications, one 

complete ureteral duplication and one case with congenital 

obstruction at the ureteropelvic junction were considered 

the cause of hematuria in five patients. Finally, in one 

patient MD<strong>CT</strong>U showed a small renal angiomyolipoma. 

The <strong>CT</strong> diagnoses for patients younger than 40 years, in 

our study, were the following: ureteral calculus (n=2), 

congenital anomalies (n=2) and a negative examination 

(n=1). 

In 72 of 75 <strong>CT</strong> examinations there was excretion of the 

contrast material from the kidneys. In 50 (70%) of the 72 

<strong>CT</strong> urographies (100 ureteral segments out of 144) 

complete distention and opacification of the ureters was 

achieved (score 3). In 22 (30%) of the 72 examinations (44 

out of 144), there were ureteral segments not completely 

distended or unopacified. These included non-opacification 

of less than one third of the ureter (score 1) for 20 

(14%) ureteral units, involving the distal parts and noncomplete 

opacification of less than two thirds of the ureters 

(score 2) for 24 (16%) ureteral segments, involving the 

middle and lower parts. In these cases, clinical follow-up 

revealed no cause for the hematuria. 

The mean mAs and length of the irradiated region were 

165 mAs and 40.8 cm during the first phase, 175 mAs and 

19.2 cm during the second, 160 mAs and 39.6 cm during 

the third phase, respectively. The effective dose of the 

entire examination (scanning in three phases and PSPR) 

was 29 mSv. The stomach and gonads were the main 

contributors to the effective dose, 28% and 17% respectively 

and the kidneys the organ with the highest dose of 

75 mGy, neglecting current modulation. Using the conservative 

risk factor of 5.6% per Sv for the studied population, 

the nominal probability for stochastic effects was estimated 

to be 1.6 10 −3 . The mean skin dose assessed by in vivo 

dosimetry was 58±9 mGy. 

Discussion 

Painless hematuria is a common urological problem with a 

wide range of causes including infection, stone disease, 

tumors of the kidney and the urinary tract, drug toxicity and 

coagulopathy [22]. Traditional imaging evaluation of these 

patients included a cross-sectional study of the upper 

urinary tract (sonography, <strong>CT</strong>, or MR imaging) and IVU 

[18, 23, 24]. The results of our study demonstrated that a 

wide variety of causes for the hematuria could be 

successfully detected with multi-detector <strong>CT</strong> <strong>urography</strong> 

on a 16-<strong>row</strong> <strong>CT</strong> scanner. Using a very thin collimation, we 

were able to depict the entire renal collecting system, the 

ureters and the urinary bladder in one acquisition, obtained 

in 7–12 seconds on the average, with a resolution we 

consider very close to that of IVU, although no direct 

comparison of these two studies was performed. <strong>Multi</strong>planar 

reformations and 3D reconstructions provided 

images with excellent anatomic details, as well as IVUlike 

images. MD<strong>CT</strong>U has been well accepted by our 

clinical colleagues and, in our institution we have gone 

from performing IVU several times a week to perhaps once 

a week. 

The most common cause of hematuria in our study 

population was urothelial cancer, which was the cause of 

hematuria in 21 (28%) of 75 patients. Although our series

is small, we successfully detected seven (100%) of seven 

foci of upper tract malignancies and nine (90%) of 10 

urinary bladder malignancies, including seven tumors with 

a diameter equal or smaller than 0.5 cm. MD<strong>CT</strong>U has 

demonstrated satisfactory results in the detection of 

uroepithelial malignancies [5, 13, 15, 25]. Caoili et al. [5] 

detected 15 out of 16 foci of TCCs, including one lesion of 

5 mm in maximal diameter. The same group of 

investigators [15] retrospectively reviewing 370 MD<strong>CT</strong> 

<strong>urography</strong> examinations of patients suspected of urinary 

tract disease, identified 24 of 27 upper tract cancers, 

including five masses with a diameter equal or smaller than 

5 mm. In another series, McCarthy and Cowan [25] 

performing MD<strong>CT</strong>U and retrograde pyelography in 106 

high-risk patients correctly identified all upper tract 

malignancies, with MD<strong>CT</strong>U proving more sensitive than 

retrograde pyelography (sensitivity: 98% versus 79%). In 

the same study only one bladder cancer was not detected. 

In another multi-institutional study [13] of 350 patients 

with hematuria four patients had bladder TCCs, one had an 

urachal adenocarcinoma and only one patient had TCC of 

the upper tact, all detected on MD<strong>CT</strong>U. The above groups 

of investigators used either a 4- or an 8-detector <strong>row</strong> <strong>CT</strong> 

scanner. Our study demonstrated that 16-<strong>row</strong> <strong>CT</strong> <strong>urography</strong> 

could detect uroepithelial malignancies, including 

lesions of small size, even though a larger number of 

patients are needed to support the above data. The 

satisfactory results of 16-<strong>row</strong> <strong>CT</strong> <strong>urography</strong> in the 

detection of urinary bladder neoplasms in this study, 

perhaps they would obviate the need of performing 

conventional cystoscopy in patients presenting with hematuria 

and positive results on MD<strong>CT</strong> <strong>urography</strong>. 

Of major concern with <strong>CT</strong> <strong>urography</strong>, as well as with 

IVU, is the necessity for complete distention and opacification 

of the renal collecting systems and ureters. There is 

always a theoretical possibility that small urothelial lesions 

located in these unopacified segments could be missed. 

Other investigators, however, believe that the necessity for 

ureteral distention is simply a radiological myth and that 

urothelial neoplasms are manifested at imaging as filling 

defects or obstruction and not as underfilling of the uretes 

[4]. Even in cases of non-complete distention and opacification 

of the uretes the evaluation of the unopacified 

segments on axial images may be satisfactory [3]. The high 

negative predictive value (100%) of the non-opacified 

ureter for the presence of uroepithelial malignancies, as 

showed in this study, perhaps justifies the above statement. 

As with other multiphasic abdominal <strong>CT</strong> protocols, <strong>CT</strong> 

<strong>urography</strong> exposes the patient to increased radiation 

exposure, which has to be weighted against the expected 

benefit from the examination. We estimated an effective 

dose of 29 mSv is required for our entire protocol 

(11.1 mSv for the unenhanced scan, 5.9 mSv for the 

nephrographic phase, 11.3 mSv for the excretory phase and 

1 mSv for PSPR). This value is within the range of 25– 

35 mSv for an average size male, given by Caoili et al. [5], 

for a four-phase protocol, on a 4-detector <strong>row</strong> <strong>CT</strong> scanner. 

The same group of investigators found that MD<strong>CT</strong>U 

exposure for the same protocol was similar to the radiation 

exposure resulting from the combination of IVU and 

conventional single-phase <strong>CT</strong> examination. McTavish et al. 

[26] reported a total effective dose of 22.6 mGy, using a 

three-phase protocol, on a 4-detector <strong>row</strong> <strong>CT</strong> scanner. Skin 

dose should be also taken into account. In the present study 

the mean skin dose of 58 mGy was similar to the 54.6 mGy 

mean dose reported by Nawfel et al. [27] and lower than 

that of 74.1 mGy reported by McTavish et al. [26]. 

In conclusion, multidetector <strong>row</strong> <strong>CT</strong> <strong>urography</strong> on a 16- 

<strong>row</strong> <strong>CT</strong> scanner demonstrated satisfactory results in the 

investigation of painless hematuria, being able to demonstrate 

a wide spectrum of diseases affecting the urinary 

tract. An important advantage of the technique was its 

ability to detect uroepithelial malignancies, although a 

larger series is needed to confirm the effectiveness of 16- 

<strong>row</strong> <strong>CT</strong>U in the detection of small-sized tumors. 

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