Download Evaluation of Reconstructed Computed Temography Scanning

EL-MINIA MED., BULL., VOL. 20, NO. 1, JAN., 2009
Mamdouh
COMPUTED TOMOGRAPHY SCANNING RECONSTRUCTED
REFORMATTED IMAGING FOR MULTIPLE
RENAL STONES DETECTION
By
Mamdouh Mohamed Abol-Nasr
Urology Department, El-Minia Faculty of Medicine
ABSTRACT:
Objective: To evaluate the ability of helical computed tomography (CT) scanning
with its reconstructed reformatted images to delineate the calyceal stones and to draw
an accurate map of the staghorn renal stone inside the pelvi-calyceal system and the
benefits gained for an open renal stone surgery when the intravenous urography is
contraindicated or inconclusive.
Patents And Methods: Fourteen patients having unilateral multiple renal stones: one
huge multiple branched staghorn pelvic stone with multiple calyceal stones. One
patient had bilateral renal and calyceal stones. The fourteen patients were males with
a mean age of 41±11 years. For different indications, all patients were subjected to a
helical CT scanning with reconstruction of reformatted coronal and sagittal films at
the CT workstation to assess calyceal stones as regard their site and number. The
staghorn stone was configurated inside the pelvi-calyceal system. All patients
underwent pyelolithotomy with removal of calyceal stones without utilization of any
intra-operative stone-localizing imaging techniques. All patients had post-operative
ultrasound and/or CT-scan within one month for assessment to investigate for residual
stones.
Results: CT-scan reformatted imaging in the coronal section delineates the staghorn
stones in the renal pelves and their calyceal extensions in the fifteen involved kidneys.
On observation of the sagittal serial images for the kidney on the CT monitor, both the
stones' number and size in the anterior calyces and posterior calyces were detected
precisely with a stone-detection rate of 91.2% when compared to the operative and
post-operative imaging. In all procedures, pyelolithotomy only was done without the
need for any nephrotomy with a stone-free rate was 40% of the cases. The renal pelvic
stone could be delivered as planned pre-operatively so that the shorter calyceal stone
extension was delivered first followed by delivery of the longest one. Calyceal stones,
not detected by reformatted films, were more common in the lower renal calyces than
in the middle and upper calyces being 10.6%. Calyceal stones, not detected by the
reformatted CT films commonly occurred in stones less than one centimeter in
diameter especially in presence of multiple overlapping stones.
Conclusion: Helical CT scanning in its reconstructed reformatted images is evidently
helpful in precise delineation of the configuration of huge renal pelvic stones and
detection of associated renal calyceal stones in case of radiolucent stones and when
contrast injection is contraindicated. It helps to make pyelolithotomy least traumatic
by placing a pre-operative scenario for delivery of the staghorn stone and time-saving
by direct extraction of the pre-determined calyceal stones as surgeon becomes welloriented with stones' site and number.
KEY WORDS:
Kidney
Stone
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CT scan
Stone surgery
EL-MINIA MED., BULL., VOL. 20, NO. 1, JAN., 2009
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surgery. However, to the interpreting
radiologist, reformatted images only
occasionally add helpful information to
the axial images.5 In comparison to the
limited utility of three-dimensional
(3D) reconstructed images, multiplanar reformatted images, when
obtained using sufficiently thin collimation, might be able to substitute for
the axial images.6
INTRODUCTION:
Urolithiasis is a common
problem; the lifetime risk for stone
disease in the urinary tract approaches
20% for males and 5% to 10% for
females. The application of spiral
(helical) CT-scan for the diagnosis and
management of urinary tract stones has
altered the practice of uro-radiology
dramatically. Prior to CT-scanning, the
diagnosis of urinary tract stones relied
on plain radiography, intravenous
urography (IVU), and ultrasonography
(US).
Many
CT-scan
protocols
include
multi-planar
reformatted
images or three-dimensional (3D)
reconstructions. These images can be
created by a radiologist if the study is
being interpreted at a workstation with
3D reconstruction and multi-planar
reformatting capability. Due to improvements in software, image reformatting is now easily performed,
requiring minimal effort and time.
Helical scanning should be performed
contiguously through the kidneys down
to the bladder. Five-millimeter
collimation with a pitch of 1 to 1.6 is
used, and the data are reconstructed at
3- to 5-mm intervals. Neither oral nor
intravenous contrast medium is
administered.5
Approximately 10% of stones
contain no calcium; most of these
calculi are composed primarily of uric
acid or cystine. Pure uric acid stones
are not visible with plain film
radiography. However, almost all
urinary calculi, including uric acid
stones, are visible with un-enhanced
CT-scan.
First, the use of helical CT-scan
was used for the evaluation of patients
with acute flank pain. It is documented
that the unenhanced helical CT is more
sensitive in detecting urinary tract
stones than intravenous urograghy
(IVU).1,2,3 Helical CT has been found
to have an accuracy of 94% to 98% to
detect ureteral stones.2,3,4 A great
advancement in software and technique
has been achieved in CT so that more
precise
multi-planar
reformatted
images were reconstructed from thin
collimation and since that time, the CT
was used widely in urinary stones
imaging and evaluation. Recently, the
three-dimensional (3D) CT imaging
evolved and made a revolution in
imaging of urinary tract pathology.
The
advantages
of
this
technique compared with urography
include the speed of the examination,
the lack of a requirement for oral or
intravenous contrast media, and the
detection of non-urinary abnormalities
that mimic renal colic clinically.2,3,4
The technique has limitations, however, including difficulty in differentiating urinary calculi from nonurinary calcifications and a limited
ability to assess the degree of urinary
obstruction.5
Reformatted
reconstructed
images are often preferred by referring
urologists because the anatomy and
pathology can be demonstrated in a
fashion similar to that obtained with
IVU or to that encountered during
The reconstructed helical CTscan is also readily applied to the study
of patients with renal lithiasis. Here,
the un-enhanced CT scan is particularly important and allows identification of both radiolucent and radio278
EL-MINIA MED., BULL., VOL. 20, NO. 1, JAN., 2009
opaque calculi. The recons-tructed
imaging of calculi permits the precise
study of the number, size, and shape of
the stones and may also provide
information on stone density and
composition.6
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localize and draw a precise map of
multiple renal stones inside the pelvicalyceal system and its benefits for an
open renal stone surgery in certain
situations.
PATENTS AND METHODS:
Over a period of five years
from 2004 to 2009, fourteen male
patients were included in this study.
The mean age of the patients was 41 ±
11 years. Thirteen patients had
unilateral multiple renal stones while
one patient had bilateral multiple renal
stones. In all patients the stones had
the same distribution: one giant pelvic
stone or partial staghorn stone that was
associated with multiple calyceal
stones of different sizes distributed
among all renal calyces.
The technology is particularly
well-suited for the management of stag
horn calculi, where the reconstructed
images provide superlative views of
infundibular and calyceal stone
branches.6 This allows precise preoperative planning prior to percutaneous nephrolithotomy (PCNL),
including the number and location of
nephrostomy tracts required for
complete stone fragmentation and
removal. The clinical and economic
advantages of this imaging technique
in the management of staghorn calculi
have recently been reviewed.7 It was
reported that the reconstructed CT-scan
is an excellent adjunct in planning
anatrophic nephrolithotomy because it
allows radiographic juxtaposition of all
relevant vascular, parenchymal, and
collecting system anatomy important to
safe and successful stone surgery.5
The indication of using
reformatted CT scanning instead of
IVU in assessment was as follows. Six
patients had documented bronchial
asthma and contrast injection was
refused by all of them. Four patients
had radiolucent or faint opaque renal
stones. Two patients had documented
contrast sensitivity. One diabetic
patient had mild elevation of serum
creatinine. The last patient had
bilateral renal stones, presented with
obstructive uropathy with elevated
both blood urea and serum ctreatinine.
Lingeman and Saw used the
reconstructed helical CT in percutaneous nephrolithotripsy for stones in
the horse shoe kidney to assist in preoperative planning of the percutaneous
approach by showing the relationship
of the colon to the upper pole of the
kidney. In addition CT was used to
assess residual fragments.8
The patients were diagnosed
initially by ultrasound and plain film
of the urinary tract. The patients had
biochemical laboratory study and
complete blood picture. The four
patients with radiolucent stones
underwent intravenous urography
which was found to be inconclusive.
The patient with bilateral renal stones
underwent bilateral double-J ureteral
stenting first to overcome the
associated renal impairment. Another
patient had a double-J stent inserted to
overcome associated infection.
To date, there is no study
concerning the importance for the use
of reconstructed reformatted CT-scan
images in cases with huge branched
renal pelvic stones with multiple
calyceal stones treated by open
pyelolithotomy. This study involves
the evaluation of the ability of helical
CT scanning in its reformatted films to
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All patients were subjected to a
helical CT scanning with thin
collimation and reconstructed reformatted multi-planar coronal and
sagittal films are examined at the
workstation. The staghorn stone was
configurated within the pelvi-calyceal
system in each patient with study of
the calyces. A scenario was planned to
be followed intra-operatively for the
least traumatic steps for extraction of
the staghorn stone through the renal
pelvis itself. First, disimpaction of the
stone will be followed by its delivery
from the pelvi-ureteric junction. Then,
then the huge pelvic stone was
delivered so that the shorter calyceal
stone extension was delivered first
followed by delivery of the longest
calyceal extension at last. The calyceal
stones were evaluated as regard
number and size in each calyx.
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RESULTS:
Fifteen open renal stone
surgeries in the form of pyelolithotomy were done with and without
extension into the calyces. The
reformatted CT-scan images in the
coronal sections delineated the
staghorn stone and the direction of its
calyceal
extensions
before
all
procedures. The huge pelvic stone was
disimpacted, negotiated, and delivered
according to the extent of their
calyceal extensions.
Complications developed in
only three procedures and treated
successfully. Intra-operative hemorrhage occurred in one procedure
(6.6%). Laceration of the pelvis
towards the pelvi-ureteric junction
(PUJ) during stone extraction occurred
in two other procedures. These
lacerations were small. A double-J
stent was inserted in each of them with
meticulous closure of the renal pelvis.
All
patients
underwent
pyelolithotomy with and without
extension into calyces. Extraction of
the staghorn stone was done in the
scenario that was planned preoperatively. Then the calyceal stones
were extracted without utilization of
any of the intra-operative stonelocalizing imaging techniques and
without making any nephrotomy. The
intra-operative
findings
and
complications were documented. The
extracted stones were evaluated and
reviewed as regard their site and size.
There were additional operative findings that were dealt with
before doing the pyelotomy. Dissection and release of fibrous bands
crossing the PUJ in three patients was
done. Aberrant renal artery crossing
the PUJ was doubly clamped and cut
in one patient. Three patients had
malrotated kidneys with anterior renal
pelvis. Four patients had narrow neck
of the calyces that made lower
calyceal stones difficult to extract.
The patients were followed up
post-operatively for detection of stonerelated complications. The patients
were subjected to an ultrasound and/or
CT-scan within one month after
operation for assessment of the
presence of residual stones. The data
of the stones were gathered, divided,
and then compared according to stone
site and size in their pre-operative CT
and post-operative ultrasound status.
There were no major postoperative complications. Only one
patient only developed prolonged
urine leakage (6.6%) from the wound
for ten days. This patient underwent
cystoscopy and double-J stent
insertion and he became dry soon after
the procedure and discharged well.
The intra-operative findings and postoperative complications are shown in
table (1).
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Figure (1): Reformatted CT coronal image: pelvic stone and calyceal stones
Figure (2): Reformatted CT coronal image: pelvic stone and mid calyx stone (zoom)
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Figure (3): Sagittal reformatted CT images: pelvic stone and calyceal stones
Figure (4)
Sagittal reformatted CT images:
Staghorn stone extensions and calyceal stones (zoom)
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Figure (5)
KUB of the patient with bilateral renal stones
Figure (6)
Coronal reformatted CT images
showing bilateral staghorn stones and calyceal stones
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Figure (7)
Sagittal sections on an axial CT image
showing bilateral staghorn stones and calyceal stones
Figure (8)
Sagittal reformatted CT image in the left kidney
Showing the branches of the staghorn stone
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Table (1): Intra-operative findings and post-operative complications
Intra-operative finding
- Crossing bands at PUJ:
- Aberrant renal vessel:
- Mal-rotated kidney:
- Narrow neck of the calyx:
- Complications:
* Intra-operative bleeding:
* Pelvic lacerations:
* Prolonged leakage of urine:
Number
3
1
3
4
%
20%
6.6%
20%
26.6%
1
2
1
Surgical Action
- Release of the bands.
- Double ligature and cutting
- Pelvis was left without closure
- Left without repaired
6.6% - Compression + Blood transfusion
13.3% - Double-J insertion + closure
6.6% - Double-J stent insertion
Both the coronal and the
sagittal reconstructed images were
important in evaluation of the calyceal
stones. On observation of the sagittal
serial images on the monitor, both the
number and size of calyceal stones could
be demonstrated in the anterior calyces
groups and posterior calyces groups. In
all patients, extended pyelolithotomy
only was done without the need for any
nephrotomy for extraction of calyceal
stones. The stone-free rate was 40% of
the procedures.
As regard the middle calyceal
stones, twenty-two out of actual twentyfour stones could be detected by the
reconstructed CT films pre-operatively
with a detection rate of 91.7%. Five
retained stones were found on postoperative ultrasound (20.8%). Thus,
only two stones were missed (8.3%) on
comparing the intra-operative data with
the pre-operative and postoperative
imaging.
As regard the lower calyceal
stones, the CT reconstructed images
failed to delineate ten out of the actual
ninety-four stones (10.6%) and hence
the detection rate for lower calyceal
stones was 89.4%. These data showed
that the stone detection rate was strongly
related to the number of stones per
calyx. All the data concerning the effect
of the site of the calyceal stones on stone
detection rate of the CT reconstructed
imaging are shown in table (2).
The detection rate of upper
calyceal stones number was the most
accurate with one hundred percent
detection rate. Seventeen out of eighteen
stones were extracted intra-operatively.
There were no missed stones on
comparing the post-operative imaging
with pre-operative CT reformatted films.
Post-operative ultrasound demonstrated
a retained stone in the upper calyx in
only one patient (5.6%).
Table (2): The calyceal stone detection rates in relation to the stone site and number
Site of renal Number Removed stones
calyceal stones On the (Intraoperative)
CT
No.
%
- Upper calyx:
18
17/18
94.4%
- Middle calyx:
22
19/24
79.2%
- Lower calyx:
84
72/94
76.6%
- Total No.
124
108/136 79.4%
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Retained stones
( Post-op U/S )
No.
%
1/18
5.6%
5/24
20.8%
22/94
23.4%
28/136 20.6%
Missed stone Actual
On the CT
Stones
No.
%
No.
0
0.0%
18
2/24
8.3%
24
10/94 10.6%
94
12/136 8.8% 136
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The effect of the stone size on
the CT reformatted reconstructed
imaging detection rate was evaluated
as shown in table (3). It was found the
stone detection rate is proportionately
related the stone size. In stones
measuring more than one centimeter,
the detection rate using this technique
was one-hundred percent regardless of
the stone site in the calyces. The
stones, which size ranging from one
centimeter to 1.5 cm, could be accurately delineated by the CT reformatted
imaging technique with a detection
rate of 100%. Only seventeen out of
nineteen stones could be extracted
(89.5%).
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The detection rate of the calyceal
stones by the CT-scan reformatted
imaging was 100% in stones equal to
or more than one centimeter in
diameter. The CT reconstructed
imaging technique failed to delineate
the calyceal stones ranging from 0.5 to
0.9 centimeter in 15.8% of the stone. It
also failed to delineate the calyceal
stones less than half a centimeters in
10.7% of kidneys. According to the
size of the calyceal stone, the overall
stone detection rate of the CTreformatted imaging technique was
estimated to be 91.2% as shown in
table (3).
Table (4): The calyceal stone detection rate in relation to the stone size
Renal calyceal
Stone Size
- > 1.5 cm
- 1.0 – 1.5 cm
- 0.5 – 0.9 cm
- < 0.5 cm
- Total No.
Number Removed stones Retained stones
On the (Intraoperative) ( Post-op U/S )
CT
No.
%
No.
%
14
14/14
100% 0
0.00%
19
17/19
89.5% 2/19
10.5%
16
16/19
84.2% 3/19
15.8%
75
61/84
72.6% 23/84
27.4%
124
108/136 79.4% 28/136 20.6%
The outcome of the preplanned pyelolithtomy that was based
on the pre-operatively CT reconstructed imaging technique was shown
in table (4). First, all patient had their
renal pelvic stone extracted safely in a
safe least traumatic manner. There
were no major complications and the
nephrectomy rate was nil. The postoperative stone free rate of 40% was
achieved while one to three stones
were left in another 40% of the
procedures.
Missed stone Actual
On the CT
Stones
No.
%
No.
0
0.0%
14
0
0.0%
19
3/19 15.8%
19
9/84
10.7%
84
12/136 8.8% 136
equal to and smaller than one
centimeter in diameter. One patient
underwent percutaneous nephrostomy
for extraction of the missed residual
stones six months after operation. The
re-operation rate was 6.6% of all
procedures. The other two patients
were treated conservatively. According to the operative findings, a
double-J ureteral stent was inserted or
left in place in five operations to avoid
post-operative migration of the stones
and subsequent obstruction. The
ureteral stents were removed two
months after the operation.
Twenty percent of the kidneys
operated upon had 4-6 small stones
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Table (5): Pre-operative calyceal stones and post-operative residual stones
Pre-operative Status
Calyceal stones Kidney
* 3-5 stones:
5
* 6-10 stones:
6
* > 10 stones:
4
Post-operative status
Calyceal stones Kidney
* No stones:
6
* 1-3 stones:
6
* 4-6 stones
3
%
33.3%
40.0%
26.7%
%
40%
40%
20%
alternative diagnoses.12,13 However,
the advantage of a non-contrast imaging modality has to be balanced
against the higher radiation dose given
to the patient during CT investigation.9,14,15 It is important to know,
however, that CT examination cannot
always differentiate between radiolucent
and
radiopaque
stones.
Furthermore, CT is less suited for
follow-up after treatment of radiopaque stones.16
DISCUSSION:
Patients
with
urolithiasis
constitute an important part of everyday urological practice. The optimal
clinical management of this disease
requires knowledge of the diagnostic
imaging procedures. The clinical
diagnosis of urinary tract stones should
be supported by an appropriate
imaging procedure. Prior to the CTscanning era, the diagnosis of urinary
tract stones relied on conventional
methods of radiological diagnosis such
as plain radiography, intravenous urography, and ultrasonography. In
certain situations, the intravenous
urography may be contraindicated or it
could not delineate the kidneys and
renal stone well before stone surgery.
The application of helical CTscan for the diagnosis and management of urinary tract stones is
currently used on a large scale. The
great advancement in software and
digital technology has been achieved
so that multi-planar reformatted
images, when obtained using sufficiently thin collimation, might be able
to substitute for the axial images. With
this imaging modality, the anatomy
and pathology can be demonstrated in
a fashion similar to that obtained with
intravenous urography or to that
encountered during surgery.
During recent years, the
unenhanced helical computed tomography (CT) examinations have been
introduced as a quick and contrast-free
alternative and it replaces the intravenous urography that was considered
the gold standard for imaging of the
urinary stones for a long time.1,3,9 In
randomized prospective studies, for
patients with acute flank pain, the
specificity and sensitivity of this
method was found to be superior to
that obtained with urography.10,11 In
selected cases, additional information
regarding renal function may be
obtained by combining CT with contrast infusion. One great advantage of
CT is the demonstration of uric acid,
cystine, and xanthine stones, which are
radiolucent on plain films. Another
advantage is the ability of CT to detect
Unenhanced helical CT now
considered best overall study to
establish diagnosis of urinary tract
stones (96% sensitive), takes less than
5 minutes, no risk of contrast reaction,
detects all stone types, and rules out
other pathologic processes in patients
older patients. It takes 0.5mm cuts
from top of bladder to top of kidneys
instead of 1cm cuts in normal
abdominal CT.17,18 Non-contrast
helical CT consistently has outper-
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formed IVP in studies of patients with
suspected urinary tract stones. Because
helical CT has other advantages in this
setting (no use of contrast material,
visualization of other intra-abdominal
causes of the disease, it is becoming
the imaging procedure of choice for
these patients.1
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was selected for all patients because of
the complex nature of the stones. For
this series, an 81% stone-free rate was
obtained without major complications.20
In this study, the same idea was
used but we used non-enhanced helical
CT-scan reformatted images in
fourteen patients who had a contraindication to IVU or the intravenous
pyelogram was inconclusive and who
had staghorn stones before open
surgery. CT-scan was used for stone
delineation and drawing a map of the
staghorn and detection of calyceal
stones in the pelvi-calyceal system to
facilitate the procedure.
The most recent use of threedimensional CT pyelography for
accurate knowledge of calculus
location, how the calculus branches
and its spatial relationship within the
collecting system for planning of
percutaneous
nephrostolithotomy
(PCNL) proved its definite benefit. It
helps in planning for the most
appropriate renal access for PCNL
after careful analysis of the pelvicalyceal system anatomy with multiplanar or volume-rendered reconstructions where all relevant calculi are
well seen.. In the case of multiple
calculi or large staghorn calculus, it
should also show the best route of
access to ensure complete calculus
removal. For such focused CT pyelography of calculi, some technical
requirements need to be fulfilled.19
In the fourteen patients, there
was either a contraindication for
giving intravenous contrast. Some
patients with renal stones have bronchial asthma, some are truly sensitive
to contrast material, and some refuse
to perform intravenous urography.
Contrast medium should not be given
to, or avoided in the following circumstances: patients with an allergy to
contrast media21,22, when the serum
creatinine level is more than 150
μmol/L22, patients on medication with
metformin22-25, untreated hyperthyroidism, and patients with myelomatosis 22
Open stone surgery is currently
considered a treatment option only for
large staghorn calculi that have failed
attempts at removal with less invasive
treatments or for large staghorn calculi
that would otherwise require multiple
noninvasive treatments. Open stone
removal is also indicated in conjunction with other procedures such as
dismembered pyeloplasty that improve
urine drainage.16 Advantages of open
stone surgery are that the patient can
have a stone removed by a single
procedure with a single hospitalization. Complication rates for open
surgery are similar to percutaneous
lithotripsy.16 Morey et al reported on
sixteen open stone surgeries during a
period of ten years. An open approach
According to the pre-operative
planed scenario, all pelvic stones were
removed in one mass through a pyelotomy incision with extension into one
or more calyces. Minor complications
occurred in 20% of operations but
intra-operatively overcome. Intraoperative hemorrhage occurred in one
procedure in a patient with a malrotated kidney and a peculiar staghorn
stone directed in two planes. Stone
extraction was difficult followed by
bleeding. The bleeding was controlled
in the theatre by compression and
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EL-MINIA MED., BULL., VOL. 20, NO. 1, JAN., 2009
compensated for intra-operatively by
transfusion of two units of blood.
Single pelvic laceration from the
pyelotomy occurred during stone
extraction in two other procedures and
meticulously closed with ureteral stent
insertion.
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The reduction in the stone
detection rate from the upper calyx
down to the lower calyx rate is
strongly related to the number of
stones per calyx which is attributed to
the drainage power of each calyx
which might be related to the effect of
gravity that is least in the lower calyx.
The presence of over-crowded stones
in the lower calyx makes delineation
of all of them a difficult task.
Undoubtedly, the CT reformatted
images gave pre-operative information
that made the pyelolithotomy faster
and easier as regard disimpaction and
delivary of the stone. Open stone
surgery has the advantage of removal
of the etiological factor responsible for
and predisposing to stone formation.
In our study. These causes are extrapelvic in nature and were not detected
by this imaging modality but discovered during dissection of the upper
ureter and pelvis in about one third of
the cases.
The stone detection rate is
proportionately related the stone size.
In stones measuring more than one
centimeter, the detection rate using
this imaging technique reached a
maximum of one-hundred percent
regardless of the stone site in the
calyx. The CT reformatted imaging
was less effective in delineation of
stones less than one centimeter in
diameter with an overall stone
detection rate of 84.2% to 89.3% and
most of the missed stones on the CT
were present in the lower calyces.
According to the size of the calyceal
stones, the overall stone detection rate
of the CT-reformatted imaging
technique was estimated to be 91.2%.
So, we emphasized on results reported
before that the un-enhanced CT scan
reformatted imaging of the calculi is
particularly important in identification
of both radiolucent and radio-opaque
calculi and when IVU is contraindicated. It also allows the precise study
of the number, size, and shape of the
stones and may also provide information particularly for the management of stag horn calculi, where the
reconstructed images provide superlative views of infundibular and
calyceal stone branches.5,6,7
Both the coronal and the sagittal
reconstructed images were proved
important in evaluation of the calyceal
stones in cases where IVU was
contraindicated. The sagittal serial
images demonstrated well both the
stone number and the stone size in the
anterior and posterior calyces. In all
patients, most of the stones were
removed without the need for any
nephrotomy.
The stone detection rate in the
upper calyx was one hundred percent
without missing any stone on the CT
reformatted images. The CT reconstructed imaging was able to delineate
all upper calyceal stones. In the middle
calyx stones, the stone detection rate
was 91.7% of all stones. As regard the
lower calyx stones, the CT reformatted
images failed to delineate 10.6% of
stones. The Stone detection rate was
89.4% which is the least value of stone
detection rates when compared to the
ones of the upper and middle calyx
stones.
Other factors which make it
difficult to extract calyceal stones were
not taken into consideration in this
study. Anatomical factors include
renal malroation and deeply-situated
289
EL-MINIA MED., BULL., VOL. 20, NO. 1, JAN., 2009
intra-renal pelvis. Pathological factors
include narrow infundibulum of the
involved calyx and degree of hydronephrosis especially that of the lower
calyx. Other intra-operative situations
that force us to discontinue trials for
stone extraction include severe
bleeding, development of tears that
may extend to involve the PUJ, or
threatened PUJ avulsion.
Mamdouh
principles: In Campbelle's Urology,
Saunder' Publ. eighth edition, 2002;
Chapter 5: 122-166.
5. Kawamoto S and Fishman EK:
In CT urography: An atlas: Silverman
SG and Cohan RH; First edition,
Lippincott Williams and Wilkins,
2007: Urolithiasis; Chapter 5, 51-78.
6. Newhouse JH, Prien EL, Amis
ES, Jr, et al: Computed tomographic
analysis of urinary calculi. AJR 1984;
142 (3):545-548.
7. Hubert J, Blum A, Cormier L, et
al: Three-dimensional CT-scan reconstruction of renal calculi. A new tool
for mapping-out staghorn calculi and
follow-up of radiolucent stones. Euro
Urol 1997; 31 (3):297-301.
8. Lingeman JE, Saw KC:
Percutaneous operative procedures in
horseshoe kidneys. J Urol 1999;161
(Suppl):371
9. Kobayashi T, Nishizawa K,
Watanabe J, Ogura K. Clinical
characteristics of ureteral calculi
detected by non-enhanced computerized tomography after unclear
results of plain radiography and ultrasonography. J Urol 2003; 170 (3): 799802.
10. Worster A, Preyra I, Weaver B,
Haines T: The accuracy of noncontrast
helical computed tomography versus
intravenous pyelography in the diagnosis of suspected acute uroli-thiasis:
a meta-analysis. Ann Emerg Med
2002; 40(3):280-286.
11. Shine S. Urinary calculus: IVU
vs CT renal stone? A critically appraised topic. Abdom Imaging. 2009;
33(1):41-43.
12. Gray Sears CL, Ward JF, Sears
ST, Puckett MF, Kane CJ, Amling CL.
Prospective comparison of computerized tomography and excretory urography in the initial evaluation of
asymptomatic microhematuria. J Urol
2002; 168(6):2457-2460.
13. Mindelzun RE, Jeffrey RB.
Unenhanced helical CT evaluating
CONCLUSION:
Helical CT scanning in its
reconstructed reformatted images is
evidently helpful in precise delineation
of the configuration of huge renal
pelvic stones and detection of
associated renal calyceal stones in case
of radiolucent stones and when
contrast injection is contraindicated. It
helps to make pyelolithotomy least
traumatic by placing a pre-operative
scenario for delivery of the huge
pelvic staghorn stone and time-saving
by direct extraction of the calyceal
stones as surgeon becomes welloriented with stone site and number.
The evolving reformatted threedimensional computed tomography
will make a strong revolution in
imaging of the renal stones.
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291
‫‪Mamdouh‬‬
‫‪EL-MINIA MED., BULL., VOL. 20, NO. 1, JAN., 2009‬‬
‫استخدام االشعة المقطعية بعد اعادة صياغتها في المستويين االكليلى والسهمى‬
‫الستكشاف حصوات الكلى المتعددة‬
‫ممدوح محمد أبوالنصر‬
‫قسم المسالك البولية – كلية طب المنيا‬
‫اجريت هذه الدراسة بغرض ايضاح مقدرة االشعة المقطعية فى استكشاف حصوات الكلى‬
‫المتعددة وذلك باعادة صياغة صور االفالم المقطعية المحورية الى مناظر في المستويين ‪:‬‬
‫المستوى االكليلى ( مقاطع من االمام الى الخلف) ‪ ،‬والمستوى السهمى ( مقاطع من جانب الى‬
‫الجانب اآلخر) وذلك بعمل صورة فراغية للحصوة الكلوية الكبيرة المتشعبة من نوعية قرن‬
‫الوعل ‪ ،‬والتى يصاحبها حصوات متعددة فى كؤوس الكلى ‪ ،‬وهدفت الدراسة كذلك بيان منافع‬
‫هذا النوع من االشعة المقطعية في حاالت الحصوات التى ال تظهر باالشعة العادية ‪ ،‬وفى‬
‫الحاالت التى لديها تحسس من حقن الصبغة وحاالت ارتفاع وظائف الكلى ‪.‬‬
‫وقد اجريت هذه الدراسة على عدد اربعة عشر مريضا من الذكور ‪ ،‬ثالثة عشر منهم لديهم‬
‫حصوات بكلى واحدة ‪ ،‬ومريض واحد فقط لديه حصوات بالكليتين ‪ ،‬وكان متوسط أعمار‬
‫المرضى ‪ ٤٤ ±١٤‬عام ‪.‬‬
‫وقد أجريت لجميع المرضى اشعة مقطعية مع اعادة صياغتها في المستويين االكليلى والسهمى‬
‫قبل العملية والتى على أساسها وضعت خطوات العملية الستخراج حصوات الكلى ‪ ،‬وقد أجريت‬
‫لجميع المرضى استخراج الحصوات من الكلى بالشق الجراحى من خالل حوض الكلى من دون‬
‫استخدام اى وسائل تصويرية لتحديد مكان الحصوات أثناء العملية ‪ ،‬وتم متابعة المرضى بواسطة‬
‫االشعة التليفزيونية بعد العملية بشهر واحد لتحديد وجود حصوات متبقية بعد العملية من عدمه‪.‬‬
‫وأفرزت نتائج الدراسة أن اعادة صياغة صور األشعة المقطعية في هذين المستويين المشار‬
‫اليهما كانت هادفة في تحديد مكان وكيفية تشعب الحصاة في تجاويف كؤوس الكلى وكذلك عدد‬
‫وحجم الحصوات فى كل من كؤوس الكلى بنسبة ‪ % ۹٤٫۲‬مما سهل من تخطيط آلية استخراج‬
‫الحصاة مسبقا وتنفيذ ذلك عمليا ‪.‬‬
‫وقد تبين من الدراسة دقة استكشاف و تصوير الحصوات بهذه الطريقة أقل في حصوات الكأس‬
‫السفلى للكلى منه في الكاسين العلوى واالوسط ‪ ،‬وأن دقة استكشاف هذه الحصوات كان أقل ما‬
‫يمكن فى الحصوات الصغيرة التى يقل حجمها عن السنتيمتر الواحد وخاصة فى حال تواجد تعدد‬
‫يؤدى لتراكب الحصوات بكؤوس الكلى ‪.‬‬
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