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Journal ArticleDOI

MR imaging: a "one-stop shop" modality for preoperative evaluation of potential living kidney donors.

01 Mar 2003-Radiographics (Radiological Society of North America)-Vol. 23, Iss: 2, pp 505-520

TL;DR: Detailed description of the vascular anatomy and its relationship to the collecting system and parenchyma to facilitate the surgeon's decision making of which kidney to harvest is facilitated.
Abstract: At many institutions, magnetic resonance (MR) angiography is the technique of choice for assessment of the renal arteries and renal parenchyma in potential living kidney donors. The renal arteries and renal veins have a varied anatomy and may consist of one or more vessels at several levels with variable calibers and levels of branching. These findings may play an important role in the surgeon's decision about which kidney to harvest, especially if laparoscopic nephrectomy is used. A comprehensive MR imaging protocol is used at one hospital to assess the arteries, veins, parenchyma, and collecting system of the kidneys. The protocol includes T2-weighted single-shot fast spin-echo imaging, fat-saturated T2-weighted fast spin-echo imaging, three-dimensional MR angiography and MR venography, and delayed fat-saturated three-dimensional T1-weighted gradient-echo imaging. Meticulous assessment of the source images as well as images produced with various postprocessing methods, such as full maximum intensity projection, targeted maximum intensity projection, and axial and oblique reformation, allows detailed description of the vascular anatomy and its relationship to the collecting system and parenchyma to facilitate the surgeon's decision making. The findings of MR imaging are comparable with those of other imaging modalities.

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EDUCATION EXHIBIT
505
MR Imaging: A “One-
Stop Shop” Modality
for Preoperative Eval-
uation of Potential
Living Kidney Donors
1
LEARNING
OBJECTIVES
After reading this
article and taking
the test, the reader
will be able to:
Describe the varied
anatomy of the renal
vessels and collecting
system.
Discuss the basics
of various MR imag-
ing sequences and
postprocessing meth-
ods used for preop-
erative evaluation of
potential living kid-
ney donors.
List the advantages
of a comprehensive
MR imaging protocol
over other modalities
for evaluation of liv-
ing kidney donors.
Shahid M. Hussain, MD, PhD
Marc C. J. M. Kock, MD
Jan N. M. IJzermans, MD, PhD
Peter M. T. Pattynama, MD, PhD
M. G. Myriam Hunink, MD, PhD
Gabriel P. Krestin, MD, PhD
At many institutions, magnetic resonance (MR) angiography is the
technique of choice for assessment of the renal arteries and renal pa-
renchyma in potential living kidney donors. The renal arteries and re-
nal veins have a varied anatomy and may consist of one or more vessels
at several levels with variable calibers and levels of branching. These
findings may play an important role in the surgeon’s decision about
which kidney to harvest, especially if laparoscopic nephrectomy is
used. A comprehensive MR imaging protocol is used at one hospital to
assess the arteries, veins, parenchyma, and collecting system of the kid-
neys. The protocol includes T2-weighted single-shot fast spin-echo
imaging, fat-saturated T2-weighted fast spin-echo imaging, three-di-
mensional MR angiography and MR venography, and delayed fat-satu-
rated three-dimensional T1-weighted gradient-echo imaging. Meticu-
lous assessment of the source images as well as images produced with
various postprocessing methods, such as full maximum intensity pro-
jection, targeted maximum intensity projection, and axial and oblique
reformation, allows detailed description of the vascular anatomy and its
relationship to the collecting system and parenchyma to facilitate the
surgeon’s decision making. The findings of MR imaging are compa-
rable with those of other imaging modalities.
©
RSNA, 2003
Abbreviations: DSA digital subtraction angiography, GRE gradient echo, IVC inferior vena cava, MIP maximum intensity projection,
SE spin echo, 3D three-dimensional
Index terms: Kidney, MR, 81.1214
Kidney, transplantation, 81.455
Renal arteries, MR, 961.12942
Renal veins, MR, 966.12942
RadioGraphics 2003; 23:505–520
Published online 10.1148/rg.232025063
1
From the Departments of Radiology (S.M.H., M.C.J.M.K., P.M.T.P., M.G.M.H., G.P.K.), Epidemiology and Biostatistics (M.C.J.M.K.,
M.G.M.H.), and Surgery (J.N.M.I.), Erasmus Medical Center, Dr Molewaterplein 40, 3015 GD Rotterdam, the Netherlands. Recipient of an Excel-
lence in Design award for an education exhibit at the 2001 RSNA scientific assembly. Received March 21, 2002; revision requested May 2 and re-
ceived June 24; accepted June 25. Address correspondence to S.M.H.
©
RSNA, 2003
RadioGraphics
CME FEATURE
See accompanying
test at http://
www.rsna.org
/education
/rg_cme.html

Introduction
With the prevalence of end-stage renal disease in
the United States increasing at a rate of more
than 8% per year and disparity between the donor
supply and demand, the number of patients on
waiting lists for kidney transplants has more than
quadrupled during the past 2 decades (1,2). Dur-
ing the same period, the number of transplanta-
tions performed with cadaveric kidneys has re-
mained unchanged or increased only slightly (1).
Consequently, living donors have become in-
creasingly important in kidney transplantation
(1,2). Living donor transplantation helps reduce
the prolonged waiting time for a cadaveric kidney
and allows transplantation to be performed elec-
tively with a short cold-ischemia time (2). In ad-
dition, the recipients have better graft function
and graft survival than following postmortem or-
gan transplantation (2).
Laparoscopic nephrectomy is routinely per-
formed at our institution. The laparoscopic
method has lower morbidity, shorter hospitaliza-
tion, more rapid convalescence, and a better cos-
metic result (2). However, the laparoscopic
method requires a longer surgical in-room time.
In addition, in very obese patients and patients
with bilateral complex renal vascular anatomy,
the surgeons at our hospital prefer an open ne-
phrectomy.
With the increasing reliance on living kidney
donors in combination with laparoscopic ne-
phrectomy, an accurate preoperative assessment
of the donor is essential to minimize the risks for
the donor and optimize the results for the recipi-
ent. The preoperative assessment includes an im-
aging work-up for complete evaluation of the ar-
terial and venous anatomy, the collecting system,
and the renal parenchyma (1). Failure to identify
variations in the renal vasculature or collecting
system or to detect parenchymal abnormalities
may complicate the harvesting procedure as well
as the transplantation procedure and may com-
promise the eventual outcome for the recipient
(3).
Previously, digital subtraction angiography
(DSA), intravenous urography, scintigraphy, and
ultrasonography (US) were used in combination
to visualize the anatomy and function of the reno-
vascular and genitourinary systems (1). Recently,
computed tomographic (CT) angiography and
magnetic resonance (MR) angiography, which are
less invasive than DSA, have been introduced as
alternative techniques for the imaging work-up of
living kidney donors (4 10). Reports from several
centers mention replacement of DSA by CT an-
giography or MR angiography (9,10).
In this article, we describe our experience with
a comprehensive MR imaging protocol and vari-
ous methods for postprocessing in more than 50
living kidney donors. The ndings of MR imaging
are compared with those of other imaging modali-
ties, such as US, intravenous urography, and
DSA, to illustrate the ability of MR imaging to be
a one-stop shop modality for preoperative as-
sessment of living kidney donors.
MR Imaging Technique
For data acquisition, we use a 1.5-T system
(Signa CV/i; GE Medical Systems, Milwaukee,
Wis) with a torso phased-array coil. This is a
dedicated cardiovascular system that is equipped
with 40 mT/m high-performance gradients and
ramp sampling capability for more efcient read-
outs. After explanation of the procedure and a
brief interview to check for contraindications, an
intravenous catheter (20 gauge) is placed into the
antecubital fossa and connected to a power injec-
tor (Spectris; Medrad, Indianola, Pa). In addi-
tion, a respiratory sensor is positioned around the
patient for any MR imaging sequences with respi-
ratory gating.
At our institution, the MR imaging protocol
used to assess living kidney donors includes the
following sequences (Fig 1):
1. Coronal single-shot fast SE or half-Fourier
single-shot turbo SE imaging with the following
parameters: repetition time (msec)/echo time
(msec), /120; ip angle, 90°; and acquisition
time, 20 seconds (breath hold). This heavily T2-
weighted sequence provides an overview of the
upper abdominal anatomy, renal parenchyma,
and collecting system and serves as a localizing
sequence for planning the other sequences in the
protocol.
2. Sagittal single-shot fast SE or half-Fourier
single-shot turbo SE imaging with the following
parameters: /100; ip angle, 90°; and acquisi-
tion time, 16 20 seconds (breath hold). This se-
quence shows the anterior and posterior contours
of the kidneys as well as their relationship to the
liver and spleen.
3. Axial T2-weighted fast SE imaging with fat
saturation performed with the following parame-
ters: 2,000/100; ip angle, 90°; and acquisition
time, 2 minutes 36 seconds (respiratory trigger-
ing). This is a sequence with high contrast and
spatial resolution for detection of any renal paren-
chymal abnormalities.
506 March-April 2003 RG f Volume 23
Number 2
RadioGraphics

Figure 1. MR imaging protocol for evaluation of living kidney donors. (a) Coronal T2-weighted single-shot fast
spin-echo (SE) or half-Fourier single-shot turbo SE image shows the kidneys (arrows), which have low signal inten-
sity relative to their surroundings. This sequence allows simple and reproducible measurement of both kidneys.
(b) Sagittal T2-weighted single-shot fast SE or half-Fourier single-shot turbo SE image shows the right kidney (ar-
row) in a different orientation. (c) Axial fat-saturated T2-weighted fast SE image shows both kidneys (straight ar-
rows), which are hyperintense relative to their surroundings. Note the aorta (arrowhead) and inferior vena cava (IVC)
(curved arrow), which demonstrate signal void due to ow compensation. (d) Coronal gadolinium-enhanced T1-
weighted three-dimensional (3D) fast gradient-echo (GRE) source image shows the strongly enhanced aorta (straight
arrow) and renal arteries (curved arrows). Before acquisition of this gadolinium-enhanced data set, an identical unen-
hanced sequence is performed to assess the patients breath-holding ability and to obtain any subtraction images
needed for postprocessing. (e) Coronal T1-weighted 3D fast GRE image obtained during the venous phase shows
enhancement of the IVC (curved arrow) and aorta (straight arrow). (f ) Axial delayed gadolinium-enhanced T1-
weighted 3D fast GRE image obtained with fat saturation shows homogeneous enhancement of both kidneys (large
straight arrows) and enhancement of the left renal vein (arrowhead) and IVC (curved arrow). Note that the right re-
nal artery (small straight arrow) runs behind the IVC.
RG f Volume 23
Number 2 Hussain et al 507
RadioGraphics

4. A timing bolus sequence performed with
sagittal 3D fast GRE imaging with the following
parameters: 4.2/1.8; ip angle, 70°; and acquisi-
tion time, one image per second for 60 seconds
(free breathing). This sequence is performed after
injection of exactly 2 mL of gadolinium contrast
material with the power injector at a rate of 3 mL/
sec. This is immediately followed by 15 mL of a
saline ushing solution administered at a rate of 3
mL/sec. During imaging, the MR technologists
observe the arrival of contrast material within the
heart, thoracic aorta, and abdominal aorta. On
the basis of this imaging data set, an imaging de-
lay is calculated (see details later in this section).
5. Coronal 3D fast GRE MR angiography
with the following parameters: 4.7/1.4; ip angle,
30°; 0.6 signal acquired; 256 192 24 matrix
with a section thickness of 2.4 mm, zero-lled to
48 sections with overlapping reconstructed sec-
tions; and acquisition time, 24 seconds (breath
hold). This sequence serves as the main MR an-
giography data set and is performed before and
after the contrast material injection.
6. Coronal 3D fast GRE MR venography with
the following parameters: 4.7/1.4; ip angle, 15°;
0.6 signal acquired; 256 192 24 matrix with
a section thickness of 2.4 mm, zero-lled to 48
sections with overlapping reconstructed sections
1.2 mm thick; and acquisition time, 24 seconds
(breath hold). This sequence is started as soon as
possible after the MR angiography sequence.
Usually, about 30 60 seconds will be needed to
perform the prescanning and to adjust the imag-
ing volume on the localizing image.
7. Axial delayed gadolinium-enhanced 3D fast
GRE imaging with the following parameters: 4.9/
1.6; ip angle, 15°; section thickness of 8 mm,
zero-lled to 56 overlapping reconstructed sec-
tions 4 mm thick; and acquisition time, 21 sec-
onds (breath hold). This sequence is used to con-
rm any parenchymal abnormalities that might
have been present on the T2-weighted fast SE
images with fat saturation.
This is a comprehensive MR imaging protocol
for assessment of the renal parenchyma, renal
arteries, renal veins, and renal collecting system.
Before performance of the 3D MR angiography
sequence, a single image from the timing bolus
sequence is selected on the console and a region
of interest is placed within the aorta at the level of
the large abdominal vessels. On the basis of the
region of interest, a time-intensity curve is gener-
ated. The time-intensity curve shows the time in
seconds at which the peak enhancement of the
arterial vessels is reached. On the basis of this
time, the imaging delay for the main 3D gadolin-
ium-enhanced MR angiography sequence can be
calculated as follows: imaging delay (contrast
material arrival time) (injection time/2) (im-
aging time/2) (Fig 2). The 3D MR angiography
sequence is performed after injection of 28 mL of
gadopentetate dimeglumine (Magnevist; Scher-
ing, Berlin, Germany) with the power injector at a
rate of 3 mL/sec. The contrast material injection
is followed by 15 mL of saline ushing solution.
To depict the arteries and veins, we use two
slightly different sequences. For venous series, the
ip angle is decreased and the sequence is per-
formed after the MR angiography sequence. In
general, the tissue contrast with a GRE sequence
can be inuenced by changing the values of the
repetition time, echo time, and ip angle. By us-
ing minimum values of repetition time and echo
time, as we do for the MR angiography and MR
venography sequences at our institution, the tis-
sue contrast will mainly be inuenced by the ip
angle. In the MR angiography sequence, the
focus is on the T1-shortening effect of gado-
pentetate dimeglumine within the arteries, and
the signal from the background tissue is mini-
mized. Both of these effects are achieved by
choosing a relatively high value of the ip angle
(approximately 40°). Decreasing the ip angle,
for instance to a value of 15° as we do for the MR
venography sequence, will generate more back-
ground tissue signal. In our opinion, a lower value
of the ip angle in the MR venography sequence
is necessary to compensate for the dilution of the
gadopentetate dimeglumine that naturally takes
508 March-April 2003 RG f Volume 23
Number 2
RadioGraphics

place because of the recirculation of the contrast
medium within the vascular system as well as its
excretion by the kidneys (3).
In our experience, a frequency and phase ma-
trix of 256 192 in combination with the over-
lapping reconstructed sections in the MR angiog-
raphy sequence yielded sufcient in-plane resolu-
tion to depict the relatively small arteries within a
relatively short breath-hold time. Increasing the
frequency matrix, for instance to 512, would de-
crease the signal-to-noise ratio, and increasing the
phase matrix would increase the imaging time in
such a fashion that fewer patients would be able
to perform breath holding during data acquisi-
tion. The MR angiography and MR venography
sequences are coronal oblique series that are an-
gulated parallel to the abdominal aorta, particu-
larly at the level of the kidneys. The venous anat-
omy can also be appreciated with the axial de-
layed gadolinium-enhanced sequence. The latter
sequence, in combination with the fat-saturated
T2-weighted fast SE sequence, is also important
for visualization of the anterior and posterior con-
tours of both kidneys as well as for assessment of
any parenchymal abnormalities (3). These con-
tours of the kidneys may not be imaged well with
the coronal 3D MR angiography and MR venog-
raphy sequences because these sequences are op-
timized to cover the vasculature of the kidneys
with a minimum number of partitions in the y
direction that can be acquired within a comfort-
able breath hold. The entire protocol takes about
30 40 minutes.
Postprocessing of 3D Data Sets
After completion of all MR imaging sequences,
results of the entire examination are digitally
transported to a workstation (Advantage Win-
dows [GE Medical Systems] or EasyVision [Phil-
ips Medical Systems, Best, the Netherlands]). On
Figure 2. Timing bolus sequence. (a) Sagittal T1-weighted two-dimensional fast eld echo image (free
breathing) with a section thickness of 2 cm shows the aorta. To capture the peak enhancement of the
aorta, approximately 40 50 images are acquired at a temporal resolution of about two images per sec-
ond. This temporal resolution allows the operator to actually see the arrival of the contrast medium
within the heart, thoracic aorta, and abdominal aorta. Imaging is stopped after about 25 seconds or con-
tinued till the peak enhancement of the abdominal aorta has been satisfactorily observed. Note the region
of interest at the level of the large abdominal vessels (arrow). (b) Time-intensity curve generated from
the region of interest in a shows that the peak enhancement of the aorta at the level of the large abdomi-
nal vessels occurs at 15.7 seconds. On the basis of this value, the imaging delay for the main 3D gadolin-
ium-enhanced MR angiography sequence can be calculated as follows: imaging delay (contrast mate-
rial arrival time) (injection time/2) (imaging time/2).
RG f Volume 23
Number 2 Hussain et al 509
RadioGraphics

Figures (8)
Citations
More filters

Journal ArticleDOI
Jeroen J. Nikken1, Gabriel P. Krestin1Institutions (1)
24 Jul 2007-European Radiology
TL;DR: 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, and the advances in functional MRI of the kidney are highlighted.
Abstract: 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.

123 citations


Cites background from "MR imaging: a "one-stop shop" modal..."

  • ...A relatively large flip angle (up to 40°) can be used to minimize background signal around the high signal of the renal arteries [56]....

    [...]

  • ...Moreover, the surgeon needs to be informed about the presence of an abnormal collecting system and the presence of cysts or tumors [56]....

    [...]

  • ...A lower flip angle (15°) can be used to compensate for the lower gadolinium concentration, at the expense of more background signal [56]....

    [...]

  • ...However, it is difficult to select the proper velocity encoding gradient [6], and tortuous venous anatomy and low flow limit the use of phase contrast MRI in potential kidney donors [56]....

    [...]


Journal ArticleDOI
TL;DR: Three-dimensional gadolinium MR angiography accurately visualizes the renal arteries with almost no degradation from inplane saturation or motion artifacts and can be easily combined with other MR imaging techniques to provide a comprehensive assessment of the hemodynamic and functional significance of renal artery stenosis.
Abstract: The high accuracy of renal MR angiography makes it well suited for diagnosing renal vascular disease. A comprehensive examination includes three-dimensional gadolinium MR angiography to assess lumenal anatomy and functional techniques to assess the hemodynamic significance of any stenosis identified. Postprocessing is critical to provide reformations, maximum intensity projections, and optional volume-rendered images to display arteries in an angiographic format for optimal demonstration of any vascular lesions. It is important to review source images to avoid missing pathologic findings. As MR imaging continues to develop, the renal MR angiography examination will likely expand to include extensive functional information about creatinine clearance, flow, and response to pharmacologic agents as well as spectroscopy, diffusion, perfusion, phase contrast, and other techniques.

75 citations


Additional excerpts

  • ...MR angiography provides sufficient information about the renal arterial anatomy and is superior in diagnosing the anatomy of the renal veins in the evaluation of living kidney donors [81,82]....

    [...]


Journal ArticleDOI
27 Jun 2008-Transplantation
TL;DR: Multiple arteries may increase operation time and accessory lower pole arteries are associated with a higher rate of recipient ureteral complications indicating the importance of arterial imaging.
Abstract: BACKGROUND.: Live donor kidneys with multiple arteries are associated with surgical complexity for removal and increased rate of recipient ureteral complications. We evaluated the outcome of vascular imaging and the clinical consequences of multiple arteries and veins. METHODS.: From 2001 to 2005 data of 288 live kidney donations and transplantations were prospectively collected. Vascular anatomy at operation was compared with vascular anatomy as imaged by magnetic resonance imaging (MRI) or subtraction angiography, and consequences of multiple vessels were investigated. RESULTS.: Simple renal anatomy with a solitary artery and vein was present in 208 (72%) kidneys. Sixty (21%) transplants had multiple arteries. Thirty (10%) transplants had multiple veins. Magnetic resonance imaging failed to predict arterial anatomy in 23 of 220 donors (10%) compared with 3 of 101 (3%) after angiography. The presence of multiple veins did not influence outcomes after nephrectomy in general. Multiple arteries did not affect clinical outcomes in open donor nephrectomy (n=103). In laparoscopic donor nephrectomy (n=185) multiple arteries were associated with longer operation times (245 vs. 221 min, P=0.023) and increased blood loss (225 vs. 220 mL, P=0.029). In general, neither multiple arteries nor vascular reconstructions influenced recipient creatinine clearance or ureteral complication rate. However, accessory arteries to the lower pole correlated with an increased rate of ureteral complications (47% vs. 14%, P=0.01). CONCLUSIONS.: Multiple arteries may increase operation time. Accessory lower pole arteries are associated with a higher rate of recipient ureteral complications indicating the importance of arterial imaging. Currently, both magnetic resonance imaging and angiography provide suboptimal information on renal vascular anatomy.

73 citations


Cites background from "MR imaging: a "one-stop shop" modal..."

  • ...In our hospital, angiography was gradually replaced by MRI as this technique does not cause radiation and, in addition, provides information on venous anatomy (14)....

    [...]


Journal ArticleDOI
James F. Glockner1, Terri J. Vrtiska1Institutions (1)
01 Jun 2007-Abdominal Imaging
TL;DR: Techniques for optimizing renal MRA and CTA are reviewed, the advantages and limitations are assessed, and the current indications for renal vascular imaging including renal artery stenosis screening are provided.
Abstract: During the past decade, noninvasive CTA and MRA imaging techniques have replaced catheter angiography for evaluation of the renal arteries. This article reviews techniques for optimizing renal MRA and CTA, assesses the advantages and limitations of MRA and CTA, and provides the current indications for renal vascular imaging including renal artery stenosis screening. New and future developments in these rapidly evolving techniques are also discussed.

48 citations


Journal ArticleDOI
30 Jan 2006-Abdominal Imaging
TL;DR: Combined magnetic resonance imaging protocols including MR urography, gadolinium-enhanced MR angiography, and MR renography have evolved as a “one-stop” diagnostic technique in the evaluation of the entire graft and peritransplant region, enabling improved patient convenience, less morbidity, and a potential cost saving.
Abstract: Renal transplantation is an established treatment for patients with end-stage renal disease. Many causes of graft dysfunction are treatable, making prompt detection and diagnosis of complications essential. Sensitive, noninvasive imaging procedures, which do not use iodinated contrast media, are therefore highly desirable to evaluate graft function. Duplex sonography (US) has traditionally been the initial investigation of graft dysfunction. US offers many advantages, particularly during the postoperative period, when it can be performed portably regardless of renal function and can guide percutaneous procedures. However, US lacks specificity in assessing hydronephrosis, cannot differentiate parenchymal causes of dysfunction, and may have difficulty assessing transplant vessels. Recently comprehensive magnetic resonance imaging (MRI) protocols including MR urography, gadolinium-enhanced MR angiography, and MR renography have evolved as a "one-stop" diagnostic technique in the evaluation of the entire graft and peritransplant region. Multiplanar capabilities enable MRI to identify the site of urinary obstruction and assess renal vessels in their entirety. The evolving technique of MR renography may also differentiate parenchymal causes of dysfunction. By combining these three components into a single examination, further information may be obtained regarding the graft when compared with US and other conventional studies, with improved patient convenience, less morbidity, and a potential cost saving.

48 citations


Cites background from "MR imaging: a "one-stop shop" modal..."

  • ...Similar ‘‘onestop shop’’ MR protocols have been used to preoperatively evaluate potential living kidney donors, with findings comparable with those of other modalities [11, 12]....

    [...]


References
More filters

Book
01 Jan 1988-
Abstract: The developing human : , The developing human : , کتابخانه دیجیتالی دانشگاه علوم پزشکی و خدمات درمانی شهید بهشتی

1,188 citations


"MR imaging: a "one-stop shop" modal..." refers background in this paper

  • ...Similarly to vascular anatomic variations, duplication of the upper urinary tract, particularly duplication of the abdominal parts of the ureter and renal pelvis, is common (11)....

    [...]

  • ...Vascular anatomic variations result from persistence of embryonic vessels that normally disappear when the definitive renal vessels form (11)....

    [...]

  • ...According to the classic anatomy literature, about 20%–30% of kidneys have two or more arteries (Fig 8), and multiple vascular supply by more than three vessels to one kidney is possible (11)....

    [...]

  • ...These abnormalities result from the division of the ureteric bud (11)....

    [...]

  • ...The extent of ureteral duplication depends on how complete the division of the diverticulum is (11)....

    [...]


Book
23 Dec 1997-
TL;DR: Basic concepts thoracic aorta pulmonar arteries abdominal aort a renal arteries mesentric arteries portal vein peripheral arteries extracranial carotid arteries are presented.
Abstract: Basic concepts thoracic aorta pulmonar arteries abdominal aorta renal arteries mesentric arteries portal vein peripheral arteries extracranial carotid arteries. (Part contents)

147 citations


Journal ArticleDOI
Myron A. Pozniak1, D J Balison, Fred T. Lee, R H Tambeaux  +2 moreInstitutions (1)
01 May 1998-Radiographics
TL;DR: Correlation with surgical findings in 136 donor nephrectomies helped confirm a high level of accuracy for CT angiography in the assessment of the renal vasculature, thus reducing the risks and complications associated with the harvesting procedure and improving the chances for a successful outcome.
Abstract: Renal transplantation has grown rapidly over the past 30 years, resulting in an inadequate supply of organs to meet the ever-increasing demand. This has led to an increase in the number of living-related donors. Advances in imaging technology now allow safe, rapid, and relatively noninvasive evaluation of potential donors. Helical computed tomographic (CT) angiography is a fast, minimally invasive procedure that is quickly becoming the imaging modality of choice for preoperative evaluation of potential renal transplant donors. Helical CT, combined with low-osmolar intravenous contrast materials, has enabled CT angiography to depict arterial and venous anatomy accurately. Between July 1995 and March 1997, CT angiography was performed in 205 potential renal donors. Correlation with surgical findings in 136 donor nephrectomies helped confirm a high level of accuracy for CT angiography in the assessment of the renal vasculature: Sensitivity and specificity for identifying specific vessels was 99.6% and 99.6% ...

116 citations


"MR imaging: a "one-stop shop" modal..." refers background in this paper

  • ...The most common variant of the left renal vein is a circumaortic configuration, which occurs in about 5%–7% of cases (Fig 9) (4)....

    [...]

  • ...A single retroaortic left renal vein can be seen in 2%–3% of individuals (4)....

    [...]

  • ...Recently, Pozniak and colleagues (4) described the anatomic variations of the renal vessels in an article based on their experience with CT angiography....

    [...]

  • ...Usually, renal calculi larger than 5 mm or multiple calculi have consequences for the harvesting procedure (4)....

    [...]

  • ...These veins empty into the left renal vein in about 75%, 100%, and 100% of individuals, respectively (4)....

    [...]


Journal ArticleDOI
Sachiko T. Cochran1, R M Krasny, G M Danovitch, Jacob Rajfer  +3 moreInstitutions (1)
TL;DR: Use of CT angiography plus conventional radiography instead of excretory urography and conventional arteriography can result in a 35-50% reduction in cost of the imaging studies in potential renal donors.
Abstract: OBJECTIVE. This prospective study was intended to determine if helical CT arteriography plus conventional radiography is sufficiently accurate to replace and less costly than excretory urography and conventional renal arteriography, the techniques currently used to examine living renal donors. SUBJECTS AND METHODS. Patients underwent CT arteriography with a helical CT scanner. Conventional radiographs were obtained during the pyelographic phase to evaluate the urothelium. Findings on CT arteriograms were compared with findings on conventional arteriograms and at surgery. RESULTS. Of 57 patients who underwent CT arteriography, 46 also underwent conventional arteriography and 40 underwent surgery. For those 46 patients, we found agreement between results of CT arteriography and conventional arteriography in 89% of kidneys. For those 40 patients, we found agreement between results of CT arteriography and findings at surgery in 90% of kidneys and agreement between results of conventional arteriography and findings at surgery in 87% of kidneys. Of the 57 patients, six (11%) had findings on CT angiograms that precluded further consideration for donation. CONCLUSION. Eight to ten percent of renal arteries are not seen on renal arteriograms when compared with findings at surgery. Our results indicate that CT arteriography is as accurate as conventional arteriography at revealing the number of vessels that perfuse and drain the kidneys and can replace conventional arteriography. Use of CT angiography plus conventional radiography instead of excretory urography and conventional arteriography can result in a 35-50% reduction in cost of the imaging studies in potential renal donors.

100 citations


Journal ArticleDOI
Russell N. Low1, A Martínez, S M Steinberg, G D Alzate  +4 moreInstitutions (1)
01 Apr 1998-Radiology
TL;DR: Combined gadolinium-enhanced MR angiography, MR urography, and MR nephrographY can accurately depict the arterial supply, collecting system, and renal parenchyma of donor kidneys.
Abstract: PURPOSE: To determine prospectively the feasibility and accuracy of combined gadolinium-enhanced magnetic resonance (MR) angiography, MR urography, and MR nephrography in the presurgical evaluation of potential renal transplant donors. MATERIALS AND METHODS: Twenty-two potential donors for renal transplantation were evaluated with 1.5-T MR imaging. MR angiograms were evaluated for the number of renal arteries, presence of early arterial branches, and renal artery stenoses. The renal collecting system and ureters were evaluated on the MR urograms. Renal parenchyma was assessed on the MR nephrogram. Prospective interpretation of MR images was compared with that of conventional angiograms and excretory urograms and with surgical findings. RESULTS: Gadolinium-enhanced MR angiography enabled correct identification of the arterial supply to all 44 native kidneys (44 single or dominant renal arteries and nine accessory renal arteries), four of five early arterial branches arising in the proximal 2 cm of the renal artery, a mild truncal stenosis in one renal artery, and two anomalies of the draining renal veins. The MR urogram accurately depicted a duplicated collecting system and mild unilateral pelvicalicectasis. The MR nephrogram showed renal size and a solitary cyst in one kidney, confirmed with sonography. CONCLUSION: Combined gadolinium-enhanced MR angiography, MR urography, and MR nephrography can accurately depict the arterial supply, collecting system, and renal parenchyma of donor kidneys.

92 citations