The Egyptian Journal of Radiology and Nuclear Medicine (2011) 42, 87–92

Egyptian Society of Radiology and Nuclear Medicine

The Egyptian Journal of Radiology andNuclearMedicine

www.elsevier.com/locate/ejrnmwww.sciencedirect.com

Role of the MDCT urography in diagnosis

of renovascular diseases

Hasan I. Megallya,*, Ayman Mohamed Seliem

a,1, Adel kurkar Abdalla

b,2

a Department of Diagnostic Radiology, Faculty of Medicine, Assiut University, Egyptb Department of Urology, Faculty of Medicine, Assiut University, Egypt

Received 3 September 2010; accepted 12 December 2010

Available online 24 March 2011

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KEYWORDS

MDCT;

Renovascular;

Urography

Corresponding authors. Tel.

mail addresses: hasanibra

ymanassuit@hotmail.com (A

.kurkar Abdalla).

Tel.: +20 104507778.

Tel.: +20 180247705.

78-603X � 2011 Egyptian

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uclear Medicine.

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edicine. Production and host BY-NC-ND license.

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Abstract Purpose: The current study aimed to evaluate the efficiency of the MDCT urography in

the diagnosis of renovascular diseases.

Material and methods: Ten consecutive patients were recruited from the Urology out patients’ clin-

ics of Assuit University. Their ages ranged from 22 to 60 years. Prior to Multidetector Computed

Tomography (MDCT) examination, relevant clinical data and renal function tests were obtained in

every patient.

Result: In the current study MDCT easily diagnosed during the arterial phase, six patients with

renal aneurysms, two patients with nutcracker syndrome, one patient with arteriovenous malforma-

tion (AVM) and one patient of renal artery stenosis.

Conclusion: MDCT plays an important role in the evaluation and management of both primary

renovascular disease and the secondary manifestations of each disease. MDCT angiography with

multiplanar reconstruction and three-dimensional display is valuable in studying patients with reno-

vascular lesions involving the proximal renal vessels.� 2011 Egyptian Society of Radiology and Nuclear Medicine. Production and hosting by Elsevier B.V.

All rights reserved.

6209584.

ahoo.com (H.II. Megally),

m), kurkar701@hotmail.com

of Radiology and Nuclear

tian Society of Radiology and

lsevier

sevier B.V.Open access under

1. Introduction

In the past decade, the ability to detect and characterize uri-nary tract lesions has been refined to an unprecedented degree.During this period cross sectional imaging with ultrasonogra-

phy (US), computed tomography (CT), and in some cases,magnetic resonance imaging has become central to the investi-gation of the urinary tract disease (1).

With the recent introduction of multi-detector row helicalCT (MDCT), the uroradiologic evaluation of patients withcommon and complex diseases is changing rapidly. MDCT

scanners provide a huge gain in the performance of spiralCT technology that permit renal images to be acquired duringany or all the three phases of contrast enhancement and

88 H.I. Megally et al.

characterize the renal vasculature, the renal parenchyma and

the collecting system in a single imaging design (2).Multidetector computed tomography urography (MDCTU)

is a novel imaging technique that provides high resolutionimages of the entire renal collecting system in a single helical

scan (3).This technique, also provides a comprehensive evaluation

of the genitourinary tract for patients with hematuria and re-

quire evaluation of both the renal parenchyma and the urothe-lium (4).

The term CTU is often used in clinical practice for multi-

tude of MDCT scanning techniques for the evaluation of theurinary tract. Such terminology leads to confusion and ambi-guity regarding the exact nature of studies undertaken. Basi-

cally computed tomography urography (CTU) can be seen asexcretory urography in which MDCT is employed for theimaging of the urinary tract (5).

CTU is defined as dedicated, usually multiphasic, CT scan-

ning techniques optimized for imaging the urinary tract inwhich high-resolution images of the entire urinary tract are ob-tained following excretion of the intra vascular contrast media

whereby at least one series should be performed in the excre-tory phase (5).

CTU may diagnose a multitude of pathologies including re-

nal masses, upper tract urothelial tumors and benign abnor-malities, such as papillary necrosis , urolithiasis, infection,fibroepithelial polyps, trauma, and normal variant anatomy(6).

Multidetector CT urography (CTU) has several advantagesthat include absence of respiratory misregistration, rapid imag-ing with optimum contrast medium pacification, reduced par-

tial-volume effect because appropriate slices can be selectedfrom the volumetric data, and acquisition of multiple thinoverlapping slices providing excellent two- and three-dimen-

sional reformations. These advantages offer CTU as a compel-ling alternative to excretory urography (EU) and (US). MDCTplays an important and three-dimensional display and is valu-

able in studying patients with vascular processes involving theproximal renal vessels (1).

MDCT angiography is advantageous compared to conven-tional angiography being a non-invasive technique that can be

done on out patient basis without pre or post-procedureadmission, no angiographic team or equipment needed, nospecial post-procedure care as conventional angiography, less

cost, also no risk of the role in evaluation and managementof both primary renovascular disease and the secondary man-ifestations of each disease MDCT angiography with multipla-

nar reconstruction thromboembolism or local complicationsthat may occur in conventional angiography.

2. Patients and methods

This study included ten consecutive patients who were re-

cruited from the Urology out patients’ clinics of the AssuitUniversity. Their ages ranged from 22 to 60 years. Prior toMDCT examination, relevant clinical data, operative history,and renal function tests were obtained in every patient. All pa-

tients were scanned using 64-rows multi detectors CT (MDCT)(Toshiba aquilion 64, Medical system. No special preparationwas needed. Positive contrast media for the bowel was avoided

as they interfere with the evaluation of three dimensional (3D)

images. Oral hydration with water used to promote diureses

and to act as a negative contrast medium for the upper gastro-intestinal tract. All patients were encouraged to drink up to1000 ml water the hour before scanning. Four phase CT urog-raphy protocol was applied in all the examined patients. Four

phase technique included unenhanced phase and imaging inarterial (corticomedullary), nephrographic and excretoryphases. Four phases Single bolus technique include:

1. Precontrast scan:– The patient was scanned from the diaphragm to the

symphysis pubis.

2. Post contrast scans:

– Venous line in an antecubital vein is a prerequisite.– One hundred twenty milli liters of non ionic con-trast media (Iopamidol, 300 mg/ml) was injected at a ra-te of 3 ml/s using a commercially available automatic

injector.– In the arterial and nephrographic phases, the patientwas scanned between the diaphragm and the iliac crest.

In the excretory phase scanning was limited to the kidneys,ureters and UB ‘‘from L1 to symphysis pubis to decreasethe patient radiation dose.

– Using an automatic bolus tracking method, scanningwas initiated, with a delay of 5 s after triggering at a thre-shold of 100 HU in the region of interest at the supra renallevel of abdominal aorta.

– Scanning was performed during three phases:(a) Arterial (corticomedullary) phase: with automatic

detection of contrast media.(b) Nephrographic phase: 50 s after the end of the arterialphase.

(c) Delayed phase: 7 min after the end of the nephro-graphic phase. In renal trauma group, patients with urinarybladder (UB) lesions delayed phase were postponed to an

average of 20 min after the end of the nephrographic phase.

Scanning parameters for MDCT protocol:

Pre contrast images Post contrast images

Tube voltage 120 kvp 120 kvp

MAS/Slice 200 MAS 200 MAS

Increment 100 mm .45 mm

Resolution Standard Standard

Collimation 64 · 0.625 64 · 0.625

Pitch 0.984 0.984

Rotation time 0.75 s 0.5 s

Slice thickness 2 mm 0.9 mm

Field of view Large Large

Matrix 512 · 512 512 · 512

3. Results

Our study included 10 patients, six patients with renal aneu-rysms, two patients with nutcracker syndrome, one patient

with AVM and one patient of renal artery stenosis, who under-went angioplasty via balloon dilatation (Table 1).

All cases of renal aneurysms were correlated with conven-

tional angiography (Fig. 1).

Table 1 Types of reno-vascular disorders found in our study.

Types of vascular disorders Number of cases % in this group

Renal aneurysm 6 60

Nut cracker syndrome 2 20

Renal AVM

Renal artery stenosis

1

1

10

10

Total 10 100

Role of the MDCT urography in diagnosis of renovascular diseases 89

Two patients of nut cracker syndrome, one was anteriorand the other was posterior nut cracker syndrome (Fig. 2).They had a history of hematuria 6 months ago, they hadundergone a variety of diagnostic studies, including repeated

urine cytology, urethrocystoscopy, renal US, intravenousurography (IVU) and computed tomography angiography(CTA). Conventional angiography was obtained to confirm

the diagnosis (Fig. 2, nut cracker anterior).One patient presented with left loin pain, plain urinary tract

(PUT) was free, abdominal US showed multiloculated cystic

lesion in the renal hilum, Color Doppler ultrasound revealedturbulence of color signals with a mosaic pattern, whilespectral Doppler revealed high velocity systolic upstroke

Figure 1 (A) Precontrast axial CT shows hypodense right hilar mar

shows intense enhancement of the lesion similar to that of the aorta. (

renal artery.

(160 cm/s) with a low resistivity index (RI) (0.3). CTA revealed

in the pre contrast scan, a fairly defined hypodense cysticlesion with curvilinear calcification at the renal hilum. Aftercontrast administration in arterial phase, the lesion showed in-tense contrast enhancement with early intense opacification of

the left renal vein. The left renal artery is seen dilated, promi-nent and follows a tortuous course. Another venous structureis seen drained into the left renal vein and showed marked

prominence and dilatation along its course which is the leftgonadal vein. At nephrographic phase, the lesion became iso-dense to the renal parenchyma and hypodense at the delayed

phase due to a rapid washout. The vascular lesion was diag-nosed as AVM. The diagnosis was confirmed by conventionalangiography which revealed that the main renal artery was the

main feeding artery (Fig. 3).A young patient (22 year) presented clinically with severe

hypertension, that was nearly controlled by three anti hyper-tensive drugs. By color Doppler US, the interarenal parame-

ters revealed a prolonged acceleration time up to 100 cm/s,while the extra renal parameters showed high P.S.V of180 cm/s with color flow turbulence at the stenotic site and

spectral broadening. CTA revealed left renal artery stenosis.This case was confirmed by catheter angiography and wasmanaged by balloon dilatation.

ginally calcified lesion. (B) Postcontrast axial CT (arterial phase)

C) MIP coronal oblique view shows its continuity with ipsilateral

Figure 2 (A and B) Post contrast axial CT (arterial phase) shows compression of left renal vein between the aorta and spine. (C and D)

Sagittal views well show the compression of the left renal vein between aorta and spine (e) coronal MIP shows normal both PCSs.

90 H.I. Megally et al.

4. Discussion

Traditionally, EU with or without US has been utilized as theinitial imaging approach to evaluate patients with hematuria.However, over the past few years, CT urography has emergedas the best single imaging test for comprehensive evaluation of

the urinary tract, while CT is acknowledged to be superior toEU and US in its ability to detect and characterize renal le-sions (6).

The renal aneurysm is often discovered incidentally duringimaging or at autopsy (7).

Helical CTA with 2D and 3D display can play a primary or

complementary role in demonstrating the origin of the aneu-rysm and its relationship to the renal arteries (8).

In the present study six cases of renal aneurysms were diag-nosed by CTA which were confirmed by conventional

angiography.Nutcracker (NC) syndrome is characterized by left-sided re-

nal bleeding due to compression of the left renal vein (LRV) in

the fork either between the abdominal aorta and the superiormesenteric artery (SMA) (anterior NC) or between the abdom-inal aorta and the spine (posterior NC). These result in left re-

nal venous hypertension leading to the development ofcollateral veins with intra renal and peri renal varicosities,which can cause hematuria if the thin-walled septum separat-

ing the veins from the collecting system ruptures. The mainpresenting symptom is hematuria, with or without left flankpain (9).

The diagnosis of NCP can be established by venographic

imaging or IA-DSA. Since these examinations are relativelyinvasive, a less-invasive method for diagnosis is desirable andseveral methods to confirm the presence of compression of

LRV have proposed for this purpose: CTA (38), SimpleMRI and MRA (10).

In the two cases including in this study, one patient present

by flank pain and other with microscopic hematuria, they were

diagnosed by MDCT. This method could visualize the princi-pal vascular abnormalities of NCP, i.e., abnormal branchingof SMA from the associated abdominal aorta.

Renal arteriovenous malformations (AVM) are rare and

are of three types: congenital, acquired and idiopathic (11).Acquired renal AVMs are commonest and account for 70%

of the cases and develop following trauma, surgery, biopsy,

malignancy and inflammation. AVMs developing after percu-taneous biopsy are asymptomatic and close spontaneouslywhereas post-traumatic AVMs are more likely to be symptom-

atic. Congenital renal AVMs account for 27% of cases and canbe described under two categories: classic and aneurysmal.Classic congenital renal AVMs appear as cirsoid intrarenal

malformations and present with gross hematuria. Aneurysmalcongenital renal AVMs more commonly present with anabdominal bruit, hypertension or high output cardiac failure.Idiopathic renal AVMs are rare and account for about 3%

of the cases. Radiologically, they can be described as acquiredfistula with an artery communicating directly with one or moreveins with no obvious cause (12).

Sandip et al. discovered a large AVM in the kidney by colorduplex image (CDI) and selective renal angiography which mi-micks a cyst by US. In our study a large AVM was found in

the renal pelvis by CTA and CDI which mimicks hydrone-phrosis by US. In addition CTA showed that the feeding arterywas the main renal artery.

Most reports have shown that CTA and contrast enhanced

MRA are the best non-invasive tests for documenting renal ar-tery stenosis in patients suspected of having renovascularhypertension (13).

While CTA and magnetic resonance angiography (MRA)provide similar results for the detection of renal artery stenosis,CTA is technically simpler to perform and is less expensive.

Color-coded duplex ultrasound is an alternative whenever askilled examiner is available and when technical conditionsfor an US examination of a patient are good. (13).

Figure 3 Multiphasic spiral CT shows AVM. (A) Axial NCCT shows left isodense cystic renal pelvic mass with fine calcifications. (B)

Maximum intensity projection (MIP) axial oblique view (arterial phase) shows intense enhancement with early opacification of the left

renal vein. (C) MIP axial oblique view (nephrographic phase) shows the contrast still seen. Left renal artery is seen dilated. Circumaortic

left renal vein is noted. (D) Axial postcontrast image shows washout of contrast media at excretory phase. (E) MIP coronal oblique and

(F) sagittal oblique images both show the same findings with dilated left gonadal vein.

Role of the MDCT urography in diagnosis of renovascular diseases 91

MDCT may not be suitable for all patients. The requiredcontrast volume is significant. In the patient with renal insuffi-ciency, MDCT is not an ideal screening test for renal artery

stenosis. Similar to renal duplex US, CTA may be limited inobese patients. Many CT scanners have a weight limit forthe table movement above which the movement may be

92 H.I. Megally et al.

impaired. This limitation may impede smooth movement of

the table through the scan volume and result in poor imagequality. When successful, CTA can identify the location ofthe stenosis or occlusion, help identify the etiology of the reno-vascular disease, locate and quantify accessory vessels, and

provide anatomic information about other important abdom-inal structures, such as the abdominal aorta, visceral bloodvessels, and adrenal glands (14). In the present study only

one patient had osteal stenosis of the renal artery which wasdiagnosed by Doppler US and CTA. The case was confirmedby conventional angiography and was managed by balloon

dilatation.

5. Conclusion

MDCT plays an important role in the evaluation and manage-ment of both primary renovascular disease. MDCT angiogra-

phy with multiplanar reconstruction and three-dimensionaldisplay is valuable in studying patients with renovascularlesions involving the proximal renal vessels.

MDCT angiography is advantageous compared to conven-

tional angiography being a non-invasive technique that can bedone on out patient basis without pre or post-procedureadmission, no angiographic team or equipment needed, no

special post-procedure care as conventional angiography, lesscost, also no risk of thromboembolism or local complicationsthat may occur in conventional angiography.

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