A large renal pelvic diverticulum, presenting incomplete excretion during tc-99m MAG-3 scintigraphy and tracer accumulation on tc-99m DMSA scintigraphy; a case report.

Abstract

This case report illustrates the dynamic and static renal scintigraphic images of a patient with an unusual large diverticulum of the renal pelvis. The initial diagnosis by intravenous pyelography (IVP) and ultrasonographic (US) examination was a renal pelvic diverticulum of the left kidney, and the patient was referred to the nuclear medicine department for exploration of the effect of the pelvic diverticulum on renal functions. We performed dynamic renal scintigraphy with technetium-99m (Tc-99m) labeled mercaptoacetyl triglycine (MAG-3) and static renal scintigraphy with Tc-99m labeled dimercaptosuccinic acid (DMSA). In dynamic renal scintigraphy, bilaterally normal concentration function was observed. While right kidney excretion function was normal, an incomplete excretion pattern was seen on the left side. Complete urinary flow obstruction occurred approximately at the 10th minute of the acquisition, which did not seem to respond to the i.v. furosemide application. However, when only the renal cortex was included in the region of interest, the obstructive pattern disappeared. In static renal scintigraphy, a large renal pelvic diverticulum localized antero-medially was clearly visualized in the left-anterior oblique projection, most probably due to accumulation of radiopharmaceutical inside it. This case showed that a renal pelvic diverticulum should be thought of when an incomplete excretion pattern is seen on dynamic renal scintigraphy. Using only a cortical region of interest may also help to distinguish other types of obstructive pattern from diverticulum. Additionally, Tc-99m DMSA scintigraphy may show diverticulum localization with antero-oblique projections in addition to routine projections.

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Vol. 18, No. 8, 2004
Annals of Nuclear Medicine Vol. 18, No. 8, 689–693, 2004
CASE REPORT
Received March 2, 2004, revision accepted July 1, 2004.
For reprint contact: Bulent Turgut, M.D., Cumhuriyet Uni-
versity, School of Medicine, Department of Nuclear Medicine,
58140, Campus, Sivas, TURKEY.
E-mail: bturgut@cumhuriyet.edu.tr
INTRODUCTION
CALICEAL (or pyelocaliceal) diverticulums are cystic, urine
containing intrarenal cavities lined with transitional cell
epithelium that communicate through a narrow channel
with the collecting system. They are congenital or
acquired anatomical abnormalities of the collecting
system.1–3 Renal pelvic diverticulum, which is a urine
filled cavity, is a rare disorder. Although there are numer-
ous reports about various interventions, management
techniques,4 treatment procedures,5–7 complications2,8
and imaging findings9,10 in patients with caliceal diver-
ticulum, there are few reports on renal pelvic diverticu-
lum. Moreover, we could not find any reports of Tc-99m
MAG-3 dynamic renal scintigraphy or Tc-99m DMSA
scintigraphy findings in association with renal pelvic
diverticulum in the literature.
Dynamic and static renal scintigraphic techniques are
useful, non-invasive and easily applicable methods that
are used in the diagnosis of many renal diseases such as
A large renal pelvic diverticulum, presenting incomplete excretion during
Tc-99m MAG-3 scintigraphy and tracer accumulation
on Tc-99m DMSA scintigraphy; a case report
Bulent TURGUT,* Taner ERSELCAN,* Semra OZDEMIR,* Zekiye HASBEK,*
H. Bayram TOSUN* and Seher TOPAKTAS**
*Department of Nuclear Medicine, Cumhuriyet University, School of Medicine, Sivas, Turkey
**Department of Radiology, Cumhuriyet University, School of Medicine, Sivas, Turkey
This case report illustrates the dynamic and static renal scintigraphic images of a patient with an
unusual large diverticulum of the renal pelvis. The initial diagnosis by intravenous pyelography
(IVP) and ultrasonographic (US) examination was a renal pelvic diverticulum of the left kidney, and
the patient was referred to the nuclear medicine department for exploration of the effect of the pelvic
diverticulum on renal functions.
We performed dynamic renal scintigraphy with technetium-99m (Tc-99m) labeled mercapto-
acetyl triglycine (MAG-3) and static renal scintigraphy with Tc-99m labeled dimercaptosuc-
cinic acid (DMSA). In dynamic renal scintigraphy, bilaterally normal concentration function was
observed. While right kidney excretion function was normal, an incomplete excretion pattern
was seen on the left side. Complete urinary flow obstruction occurred approximately at the 10th
minute of the acquisition, which did not seem to respond to the i.v. furosemide application.
However, when only the renal cortex was included in the region of interest, the obstructive pattern
disappeared. In static renal scintigraphy, a large renal pelvic diverticulum localized antero-medially
was clearly visualized in the left-anterior oblique projection, most probably due to accumulation of
radiopharmaceutical inside it.
This case showed that a renal pelvic diverticulum should be thought of when an incomplete
excretion pattern is seen on dynamic renal scintigraphy. Using only a cortical region of interest may
also help to distinguish other types of obstructive pattern from diverticulum. Additionally, Tc-99m
DMSA scintigraphy may show diverticulum localization with antero-oblique projections in
addition to routine projections.
Key words: renal, pelvic, diverticulum, scintigraphy, MAG-3, DMSA

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renal outflow obstructions, and cortical and renovascular
dysfunction. Normal finding of dynamic renography ex-
cludes an obstructive disease, whereas loss of radionu-
clide elimination after stimulation with furosemide is
characteristic for its diagnosis.
We present here a case report illustrating the IVP, US,
dynamic and static renal scintigraphic findings of a patient
with an unusual large diverticulum of the renal pelvis.
CASE REPORT
A 29-year-old male patient with an initial diagnosis of
renal pelvic diverticulum on the left kidney was referred
to the nuclear medicine department for exploration of the
effect of pelvic diverticulum on intrarenal urinary flow by
dynamic renal scintigraphy.
The patient had been suffering from pollakiuria, noc-
turia and polyuria for six years. He did not have a previous
history of recurrent urinary tract infection, hematuria,
symptomatic calculi, dysuria, pain or fever. The actual
urine analysis was unremarkable. The blood tests showed
the following results: glucose; 106 mg/dl, blood urea
nitrogen; 17 mg/dl, urea; 36 mg/dl, plasma creatinine;
1.19 mg/dl, aspartate aminotransferase; 23 IU/l, alanine
aminotransferase; 38 IU/l, sodium; 137 mEq/l, potas-
sium; 3.5 mEq/l, chloride; 105 mEq/l.
Before the patient was referred to the nuclear medicine
department, he had an initial diagnosis of renal pelvic
diverticulum by IVP and US. Intravenous pyelography,
obtained 7 minutes after injection of contrast medium
showed opacities in the multiple dilated calices present in
upper, lower poles and middle portion of the left kidney,
while an additional opacity was observed in a large round
pelvic diverticulum at the renal pelvic region on the
delayed urogram, obtained 90 minutes after contrast me-
dium injection. No sign of calculus was observed in either
kidney. During the course of the IVP study, there was no
contrast medium transition to the left ureter (Fig. 1).
Abdominal US was performed with a SDU-450XL
(Shimadzu Diagnostic Ultrasound, Shimadzu Corpora-
tion, Japan) scanner equipped with a 2–5.5 MHz trans-
ducer. The dimensions of the right and left kidney were 65
× 130 mm and 75 × 170 mm, respectively. Transverse and
longitudinal US images revealed caliceal dilatations in
the upper as well as in the lower poles and in the middle
portion of the left kidney. Renal pelvis was seen extra-
renally and was connected to the large renal pelvic
diverticulum, measured as 80 × 100 mm (Fig. 2). Addi-
tionally, no stenosis at the uretero-pelvic junction, and no
stone were observed by US.
The dynamic renal scintigraphy with Tc-99m labeled
MAG-3 and static renal scintigraphy with Tc-99m labeled
DMSA were performed for both the evaluation of renal
functions and exploration of the effect of the pelvic
diverticulum on intrarenal urinary flow.
For dynamic renal scintigraphy, 185 MBq (5 mCi)
of Tc-99m labeled MAG-3 (Technescan® MAG-3,
Mallinckrodt Medical B.V., Holland) was injected intra-
venously to the patient in the supine position. Posterior
dynamic images [64 × 64 matrix, zoom: 1.2, 30 frame (2
sec/frame) for perfusion phase and 29 frame (1 min/
frame) for parenchymal and excretory phases] were ob-
Fig. 1 Intravenous pyelographic images of the patient obtained
at 7 and 90 minutes. R; right.
Fig. 2 Transaxial and longitudinal ultrasonographic images of
the patient show large renal pelvic diverticulum and dilated
calices in the left kidney.

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tained using a gamma camera (E-Cam, Toshiba, Japan)
equipped with low energy general-purpose collimators
and connected to a dedicated computer system for acqui-
sition (GMS-5500A, Toshiba, Japan).
Normal perfusion appearance was observed in both
kidneys in dynamic images (Fig. 3). The expected con-
centration and excretion functions were also observed in
the normal-sized right kidney by dynamic renal scintigra-
phy (Fig. 4). The left kidney was bigger than the right
kidney. During the concentration phase, left kidney had a
good, but heterogeneous radiopharmaceutical concentra-
tion and an activity defect was seen at the upper pole. An
abnormal excretion pattern was observed in the left kid-
ney. Although, spontaneous excretion was seen in the
beginning of the excretion phase in relating renogram,
complete stasis was observed approximately after the
10th minute of the acquisition. Thirty mg furosemide was
injected intravenously to the patient at the 16th minute.
However, there seemed to be no response to the i.v.
furosemide stimulation (Fig. 4 and Fig. 5-top). Static
image obtained at the end of the study showed no change
in the urine stasis in the left renal pelvic region. However,
the split renal functions, measured between 1 to 3 min
intervals were symmetrical, namely 48% on the right
kidney and 52% on the left kidney. Additionally, excre-
tory indexes at the 19th minute (EI-19 min) (EI is the ratio
Fig. 5 While normal concentration and excretion functions
were observed in right kidney, heterogeneous but good radio-
pharmaceutical concentration and complete stasis were ob-
served approx, after the 10th minute of the acquisition in left
kidney. Furthermore, there seemed to be no response to the i.v.
30 mg furosemide stimulation (Top). When regions of interest
were drawn from the upper pole and lateral renal cortical area on
the kidneys, nearly normal excretion was observed on renogram
curve in left kidney (Bottom).
Fig. 3 Images of perfusion phase [64 × 64 matrix, zoom: 1.2,
30 frame (2 sec/frame)] obtained with Tc-99m MAG-3 showing
normal symmetric perfusion in both kidneys.
Fig. 4 Dynamic renal scintigraphic images [64 × 64 matrix,
zoom: 1.2, 29 frame (1 min/frame) for parenchymal and excre-
tory phases] obtained with Tc-99m MAG-3 showing incomplete
excretion pattern in the left kidney.

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of kidney activity at 19th min to maximum activity) were
calculated as 0.20 on the right kidney and 0.64 on the left
kidney. When the analysis was repeated by using a region
of interest, comprising only the renal cortical areas, a
nearly normal excretion pattern was observed on the left
kidney renogram curve. EI was diminished to 0.43 on this
side (Fig. 5).
For the renal cortical scintigraphy, 185 MBq (5 mCi)
Tc-99m labeled DMSA (Technescan® DMSA,
Mallincrodt Medical B.V., Holland) was injected intrave-
nously to the patient on a separate day. At the 4th hour
after injection, anterior, posterior, posterior and anterior
oblique projection images (128 × 128 matrix, zoom: 1.5)
were obtained using a double head gamma camera (E-
Cam, Toshiba Corporation, Japan) equipped with low
energy high resolution collimators. In the left-anterior
oblique projection, a large renal pelvic diverticulum lo-
calized antero-medially was clearly visualized at the left
renal pelvic region accumulating radiopharmaceutical
inside it (Fig. 6). Decreased cortical activity at the upper
pole of the left kidney was also seen during Tc-99m
DMSA scintigraphy. Split renal uptakes, calculated as the
geometrical mean of the anterior and posterior projec-
tions, performed as a routine procedure in our department,
were 55% on the right kidney and 45% on the left kidney.
The decision of the urological surgeon of the patient
was removal of the lesion by surgery. The patient was
operated on, and a pelvic diverticulum was surgically
removed by an open surgical approach.
DISCUSSION
Pyelocaliceal diverticula can develop anteriorly or poste-
riorly from the kidney collecting system although they
occur more frequently posteriorly. They are frequently
associated with stone formation and infections because
of urinary stasis.3,6 Many are asymptomatic and are often
discovered as an incidental finding on IVP or other imag-
ing modalities (e.g. renal US, computed tomography
scanning, magnetic resonance imaging, retrograde py-
elography). The differential diagnosis should be made
from some other lesions like communicating cyst, renal
cortical abscess, pseudodiverticulum and tuberculosis.
In IVP, radiographic contrast material fills diverticula in
a retrograde fashion, and so delayed visualization is a
common finding.1,10 This rare anatomical abnormality
occurs in 0.21%–0.6% of the population and often con-
tains calculi.1–3,6,7,11
The anatomy of the kidney, calices, and ureter can be
imaged, and also pelvic diverticulum and caliceal dilata-
tion can be diagnosed by US, but the use of US may be
sometimes insufficient for accurate diagnosis. Because
diverticula have a thicker outer wall than most benign
cysts, the ultrasonographic appearance may also mimic a
malignant or infected cyst.10 The dynamics of the fluid in
the diverticulum or caliceal dilatations can also be evalu-
ated by IVP.9 However, the effects of this condition on the
kidney functions should be evaluated by dynamic renal
scintigraphy, which is a non-invasive imaging technique.
Only two old reports were found related to diverticula
of the renal pelvis and scintigraphy in our literature
survey.12,13
Renal scintigraphies with Tc-99m MAG-3 and Tc-99m
DMSA are known as reliable, suitable and safe approaches
to evaluate renal functions. Tc-99m labeled MAG-3 is
the radiopharmaceutical agent that allows simultaneous
investigation of renal perfusion, functional parenchyma
and collecting system. Split-total renal function and other
quantitative parameters of renal function can be deter-
mined from time-activity curves obtained from MAG-3
dynamic renal scintigraphic images.
In the present case, bilaterally normal concentration
function was observed in dynamic renal scintigraphy.
While, right kidney excretion function was normal, in-
complete excretion was seen in left kidney. Complete
urinary flow obstruction occurred approximately at the
10th minute of the acquisition, which did not respond to
the i.v. furosemide application. Two reasons can be
Fig. 7 Schematic (transaxial plane) representation according to
US findings of the renal pelvic diverticulum in the presented
case.
Fig. 6 Static renal scintigraphic projections obtained with Tc-
99m DMSA at 4th hour. Renal pelvic diverticulum apparently
visualized at anterior of the left kidney in the left-anterior
oblique projection (arrow).

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considered;
a) Positional transient obstruction; The situation was
probably due to the patient’s position and mechanical
obstruction produced by the pressure of the anterior and
middle portion-lower pole placed pelvic diverticulum on
the uretero-pelvic junction during excretion (Fig. 7).
Indeed, no stenosis or stone was observed in US examina-
tion, and the split renal function was symmetrical. It was
thought that because both the renal pelvises were located
extrarenally and the pelvic diverticulum produced posi-
tional transient obstruction, renal functions were pre-
served. However, the pressure effect of the diverticulum
by positional transient obstruction was most probably the
reason for the patient’s symptoms of pollakiuria, nocturia
and polyuria.
b) Technical reason; Incomplete excretion was due to
the superposition of the pelvic diverticulum with the left
renal ROI. In dynamic renal scintigraphy, to test the effect
of superposition on the renogram, Tc-99m MAG-3 dy-
namic images were re-processed. When the region of
interest was drawn from upper pole and lateral renal
cortical area on the left kidney, nearly normal excretion
was observed on the renogram curve (Fig. 5). This situa-
tion showed that a real obstruction was not present,
suggesting that this was due to the superposition of the
pelvic diverticulum with the left renal ROI.
Static renal scintigraphy, performed with Tc-99m
DMSA, which is a renal cortical imaging agent, is used for
obtaining information about the overall morphology of
the functioning renal units, split renal function and to
detect parenchymal abnormalities. It is a useful imaging
technique for detecting renal cortical defects and scars.
Tc-99m DMSA localizes to the renal cortex by binding to
sulfhydryl groups in proximal renal tubules. Renal uptake
of Tc-99m DMSA gives an index for the evaluation of the
functional renal cortical mass, which depends on the renal
blood flow and proximal tubular cellular membrane trans-
port function. The renal collecting system, other than the
nephron unit, is usually not visualized with this agent,
since the imaging time is usually 3–4 hours post injection
when most of the tracer has been eliminated from the
urinary tract. However, renal pelvic diverticulum was
clearly visualized in the present case because of delayed
elimination of urine from the diverticulum. Additionally,
decreased cortical activity at the upper pole of the left
kidney was evaluated as secondary to caliceal dilatation
which was quite obvious in the IVP.
In conclusion, this case showed that renal pelvic diver-
ticulum should be thought of when an incomplete excre-
tion pattern is seen in dynamic renal scintigraphy. Using
only a cortical region of interest may also help to distin-
guish other types of obstructive pattern from diverticu-
lum. Additionally, Tc-99m DMSA scintigraphy may show
the diverticulum localization with antero-oblique projec-
tions in addition to routine projections.
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