Shmuel
Cytron,
MD
Oded
#{149}
J.
Kessler,
MD
Incidental Finding during Transrectal During transrectal ultrasound (TRUS), rectal carcinoma was an mcidental finding in seven patients among a series of 5,000 TRUS examinations. TRUS was performed in seven patients with symptoms characteristic of prostatic diseases. All seven patients underwent examination by at least one physician before TRUS and, except for abnormal prostatic findings, no tumors were detected during digital rectal examination (DRE). The tumors were clearly visualized with TRUS and were easily palpated during DREs performed after TRUS. They were large and were located mainly along the postenor and lateral walls of the rectum. All the tumors were diagnosed by means of proctoscopy; the biopsy findings were positive, and the pathologic staging indicated advanced disease: adenocarcinoma of the rectum with a minimum grade of Dukes C. It is recommended that, in addition to evaluation of scans obtamed in the transverse plane, the multiplane transducer be used to evaluate the longitudinal plane of the rectum for detection of possible undiscovered tumors. Index
terms:
Prostate,
neoplasms,
844.324
Rectum, neoplasms, 757.321 #{149} Rectum, US, 757.12981 #{149}Ultrasound (US), tissue characterization, 844.324 Radiology
1992;
185:197-199
Jack
#{149}
T
MATERIALS
years)
METHODS
in whom
an abnormality
was
found
among a series of 5,000 ThUS examinalions. All seven patients complained of difficulty of micturition (Table). Patient 4 was referred for TRUS because of systemic symptoms suggestive of metastatic disease of the prostate. The patients were instructed to use a self-administered enema (Microlet; Dexon, Haifa, Israel) 4 hours before the examination. A 7-MHz transducer (model 1846; Bruel & Kjaer, Naerum, Denmark) that a 3600
scan
was
enabled
in a transverse
use
enables
moving possible
ThUS.
only;
probe,
the prostate was
of a water-filled
which
in
in the rec-
to the rectal
MD
Ciro
Servadio,
#{149}
MD
walls
The circular section of the rectum was divided into the anterior wall (10-2 o’dock position), the lateral wall (left, 2-4 o’dock position; right, 8-10 o’dock position), and the posterior wall (4-8 o’clock position). The rectal tumor was characterized by a hypoechoic
mass
that
usually
destroyed
symmetry and hindered the of the normal layers that constitute the rectal wall. After the carcinoma
the circular continuity was
diagnosed
and
localized
as being
in
an anterior, lateral, or posterior position, we reviewed the number of physicians who performed ORE (n = I or 2) before the patient was referred for ThUS. The patient was also referred to a surgeon for a rectal biopsy to confirm the diagnosis.
RESULTS Six patients
had difficulty voiding. referred for suspected metastatic disease of the prostate, mainly because of weight loss, back pain, and a suspicious prostatic finding at DRE (Table). Evaluation of the gastrointestinal tract showed that three patients had no gastrointestinal problems and that they complained about nonspecific problems such as chronic constipation. The two other patients had symptoms that might have indicated malignant tumors in the rectum: diarrhea alternating with Patient
4 was
constipation,
or fresh
blood
in their
stools. All patients
urologist TRUS.
underwent
who Three
ORE
referred
the
patients
also
by
patient
the
for
underwent
ORE by the family physician who referred them to the urologist. One patient underwent examination by a surgeon. Only two patients underwent examination by only one physician before TRUS. After the tumor was diagnosed, the urologist who performed TRUS (S.C.) also performed DRE and reported that in all
balloon.
By out, it was
the transducer in and to screen the rectum from
2 minutes.
the we
gland
localized
cm from the anus. All patients examination in this manner,
only
for
us to screen plane
him and was attached by means
used
the multiple-sector
us to screen
all planes. The transducer
6; accepted to S.C.
AND
Our study group consisted of seven patients aged 61-76 years (mean age, 69
now
received April reprint requests
Simon,
ultrasound (TRUS) is an imaging modality that enables diagnosis and staging of prostatic and rectal cancer (1,2). The cancers are acoustically less reflective than the surrounding normal tissue and yield a sonographic pattern consisting of a small number of weak echoes (3,4). The patients described herein were referred for TRUS examination to evaluate urobogic diseases. During TRUS, an unsuspected tumor of the rectum was found that had not been detected during digital rectal examination (DRE) performed by the referring physician. A meticulous DRE in which the physician concenhates not only on the anterior wall of the rectum that corresponds to the prostate but also on the posterobateral walls is important for discovery of rectal cancer in the early stages of the disease.
prostate
27, 1992; revision April 9. Address C RSNA, 1992
Dan
#{149}
RANSRETAL
enables
the Urology Institute, Beilinson Medical Center, Sadder School of Medicine, Tel Aviv University, Petah Tiqva 49100, IsraeL Received December 11, 1991; revision requested January
MD
ofRectal Carcinoma US for Prostatic Diseases’
This equipment
I From
Baniel,
1 to 14
underwent which takes
Abbreviations:
tion, ThUS
=
DRE transrectal
=
digital
rectal
examina-
US.
197
Clinical
Data in Seven
Patients
with
Rectal
Carcinoma
at TRUS
Findings
Physician Who
Symptoms
Patient No/Age
Gastrointes-
Depth
Performed
(y)
Urologic
1/72
Dysuria, frequency, nocturia, weak flow
Constipation
Dysuria, tuna,
None
None
Urologist
Mild
Chronic constipation
None
General practitioner, urologist
BPH
None
Weightloss,
Urologist
Normal
2/64
noc-
nocweak
tuna,
flow Dysuria; pected
4/62
Systemic None
sits-
Dysuria 2 y after TURP Dysuria
7/61
General
low
cancer at ORE Dysuria, nbctuna, Uigency
6/74
DRE
Location of Rectal Tumor
Urologic
prac-
BPH
Mild
Posterior
Dukes
C
12
Dukes
B
22
Dukes
C
33
Dukes
C
Lateral and posterior walls (4-B o’dock position)
27
Dukes
C
Lateral left wall Lateral right wall (7-11 o’dock position)
13
Dukes
B
17
Dukes
C
urologist
position) Posterior wall (6-9 o’clock
position) Posterior wall (4-7 o’clock position) pros-
Lateral
tate
of Adenocarcinoma
20
(5-7 o’clock
BPH
Rectal Tumor (mm)9
wall
titioner,
weakness,
prostate
5/71
Previous
weak
flow Dysuria,
3/76
tinal
Pathologic Stage
of
right
wall (1-6
back
o’clock
position)
pain Intermittent diarrhea and constipation; blood in stool None
None
General practitioner, urologist
Mild
None
Diarrhea, hemorrhoids,
None
Two urologists Surgeon, urologist
Normal prostate Mild BPH
BPH
anal
fissure
Note.-BPH = benign prostatic hypertrophy, TURP = transurethral 9Depth of rectal tumor below mucosa (from balloon wall).
1.
2.
Figures
1-3.
(1) Large
hypoechoic
tumor
on
the
3. right
side
into the rectal space because the inflated balloon hypoechoic tumor of the right rectal wall invades rectal wall. (3) Small hypoechoic tumor within the posterior fat.
protrude (2) Large
seven patients the tumors were easily palpated during DRE. A hypoechoic lesion was suspected to be rectal cancer in all seven patients
(Figs
i-3).
The
tumors
terior
side.
lient
4, the
and
6 o’clock
tumor
Radiology
#{149}
was
positions,
keeps
and
the
the space open.
all the rectal layers rectal wall invades
to the
of the gery.
distorts
anterior
rectum
and
The right seminal
on
the
adenocarcinoma
underwent
sur-
the
the
1
pos-
minute
of the
vesicle
right
enables
details
lumen.
especially
transducers not surprising this
tumor
does
not
is seen above the anterior invasion into the penrectal
gland,
resolution therefore
The
very close to the tumor.
modality
when
high-
are used. It is that in recent has
gained
great
popularity detection
visualization
of the
rectal
is situated
prostate
years,
DISCUSSION TRUS
symmetry
and the perirectal fat. The prostate all rectal layers and shows minimal
wall
had
circular
were
between
from
presses
All patients
large, and all were localized mainly on the posterior or lateral wall. In pa-
198
of the prostate.
resection
rectum
of
and
among physicians in the and staging of cancers of these organs and benign diseases of the prostate (5-7). We have used TRUS in our departOctober1992
ment during recent years lion of prostalic diseases. ity
is considered
and
precise
is an efficient
modern When
for evaluaThe modaland
diagnostic
effective
tool
in
urology.
TRUS is correctly used, a seclion with a maximum length of 14 cm, beginning from the anus, can be screened. TRUS provides a clear image of the rectal wall along its circumference, and a tumor less than 1 cm in diameter can be discovered without difficulty. Tumors of the rectum are characterized by a hypoechoic lesion that distorts the symmetry and the continuity of healthy layers. They do not protrude into the rectal space during examinalion with TRUS because the inflated balloon inserted in the recturn
keeps
the
space
open.
Whenever
the distention in barge tumors is noliceabbe, the balloon itself loses its symmetry. It is difficult to diagnose the many layers of the rectal wall in the tumor region, but it is easy to see invasion of the mucosa and muscular layers and perirectal fat infiltration. Physicians eases seem
who detect to concentrate
prostalic on the
dis-
prostate and seminal vesicles. This explains why the tumors were not found in the seven patients who underwent rectal examination, despite the barge size of the tumors and the fact that they were easily palpated after ThUS. Some patients not only had urinary symptoms but also had symptoms cupying
characteristic
of space-oc-
lesions of the rectum such as rectal bleeding, constipation, and diarrhea. The fact that we found preyously undiagnosed rectal tumors in seven patients convinced us that the physician should be aware of possible findings other than prostalic disease and therefore should examine all rec-
Volume
185
#{149} Number
1
tab walls at DRE performed for a urologic purpose. During sonographic imaging of prostatic and seminal vesides, it is valuable to also screen the rectum while one searches for a noticeable tumor. This is the advantage of the circular device that promises good imaging of the rectal wall. Recently, use of the section-screening transducer has increased the importance of complete screening of the rectum at the end of prostalic imaging. To screen the lateral and posterior walls of the rectum, it is recommended that the transducer be turned 1800 toward each side, along the bongitudinal axis. We do not perform TRUS for rectal screening. But as we perform TRUS for prostatic disorders, we scan the rectal wall when the probe is in the rectum; it takes only 2-3 minutes to do so. Of course, this cannot be compared with meticulous rectal scanning,
which
is lime-consuming
importance of a meticulous rectal examinalion of the whole rectal circumference, because haff of the rectal tumors are known to be within reach during DRE (9). At the same time, it is obvious from our study that some of the proximal rectal tumors are not detected during DRE. We believe that brief screening of the rectal walls can enable discovery of some of the undetected tumors. In our opinion, this short view of the rectal wall in the scanning field has to be an integral part of endorectal sonography. #{149} References 1.
Hildebrandt
2.
instrwnentation and clinical aspects. Colorectal Dis 1986; 1:207-230. Lee F, Gray JM, McLeary RD, et aL
Endorectal
ultrasound: hit J Pros-
tatic evaluation by transrectal sonography: criteria for diagnosis of early carcinoma. Radiology 1986; 158:91-95. 3.
but
logically can enable detection of smaller rectal lesions. Our suggestion to also image the rectum is not for early detection of rectal cancer, but for extension of the field of imaging in order to find noticeable rectal tumors. Whenever a rectal tumor is discovered during TRUS, it is recommended that, in addition to evaluation of scans obtained in the transverse plane, one use the multipbane transducer to evaluate the longitudinal plane of the rectum. The distance between the tumor edge and the anus should be known, because it is important in selection of the appropriate surgical procedure. Because the prevalence of rectal cancer is approximately 16 in 100,000 (8), it seems that the use of TRUS for screening in early detection of rectal cancer is not cost-effective and is lime-consuming. This emphasizes the
U.
4.
5.
Wang
KY, Kimmey
BristoL Rifkin
IntJ Colorectal MD, Wechsler
computed trasound orectal
6.
MB, Nyberg
DA,
et al.
Colorectal neoplasms: accuracy of US in demonstrating the depth of invasion. Radiology 1987; 165:827-829. BeynonJ, Mortensen NJ, Foy DM, Channer JL, VirjeeJ, Goddard P. Endorectal sonography: laboratory and dinical experience in
Senagore
Dis 1986; 1:212-215. BJ. A comparison of
tomography and endorectal ulin staging rectal cancer. Int J ColDis 1986;
1:219-223. jW, Senagore
A, Milsom
WI,, Scholten DJ, between intrarectal
P. Mazier
Zydbel P.
A comparison ultrasound and CT scanof experimental rectal hi-
7.
8. 9.
rung in staging mors.J Surg Res 1988; 44:522-526. Waizer
A, Zitron
5,
Ben
Baruch
D, BanielJ,
Wolloch Y, Dintsman M. Comparative study for preoperative staging of rectal cer. Dis Colon Rectum 1989; 32:53-56. Silverberg E. Cancer statistics. Cancer 1985; 35:19-35. Petersdorf RG, Adams RD, Baraunwald Isselbacher iq, MartinJG, Wilson JD. rison’s principles of internal medicine.
ed, vol 2. New Yorlc McGraw-Hill, 1763.
Radiology
can-
E, Har10th
1983;
199
#{149}
Cytron,
MD
Oded
#{149}
J.
Kessler,
MD
Incidental Finding during Transrectal During transrectal ultrasound (TRUS), rectal carcinoma was an mcidental finding in seven patients among a series of 5,000 TRUS examinations. TRUS was performed in seven patients with symptoms characteristic of prostatic diseases. All seven patients underwent examination by at least one physician before TRUS and, except for abnormal prostatic findings, no tumors were detected during digital rectal examination (DRE). The tumors were clearly visualized with TRUS and were easily palpated during DREs performed after TRUS. They were large and were located mainly along the postenor and lateral walls of the rectum. All the tumors were diagnosed by means of proctoscopy; the biopsy findings were positive, and the pathologic staging indicated advanced disease: adenocarcinoma of the rectum with a minimum grade of Dukes C. It is recommended that, in addition to evaluation of scans obtamed in the transverse plane, the multiplane transducer be used to evaluate the longitudinal plane of the rectum for detection of possible undiscovered tumors. Index
terms:
Prostate,
neoplasms,
844.324
Rectum, neoplasms, 757.321 #{149} Rectum, US, 757.12981 #{149}Ultrasound (US), tissue characterization, 844.324 Radiology
1992;
185:197-199
Jack
#{149}
T
MATERIALS
years)
METHODS
in whom
an abnormality
was
found
among a series of 5,000 ThUS examinalions. All seven patients complained of difficulty of micturition (Table). Patient 4 was referred for TRUS because of systemic symptoms suggestive of metastatic disease of the prostate. The patients were instructed to use a self-administered enema (Microlet; Dexon, Haifa, Israel) 4 hours before the examination. A 7-MHz transducer (model 1846; Bruel & Kjaer, Naerum, Denmark) that a 3600
scan
was
enabled
in a transverse
use
enables
moving possible
ThUS.
only;
probe,
the prostate was
of a water-filled
which
in
in the rec-
to the rectal
MD
Ciro
Servadio,
#{149}
MD
walls
The circular section of the rectum was divided into the anterior wall (10-2 o’dock position), the lateral wall (left, 2-4 o’dock position; right, 8-10 o’dock position), and the posterior wall (4-8 o’clock position). The rectal tumor was characterized by a hypoechoic
mass
that
usually
destroyed
symmetry and hindered the of the normal layers that constitute the rectal wall. After the carcinoma
the circular continuity was
diagnosed
and
localized
as being
in
an anterior, lateral, or posterior position, we reviewed the number of physicians who performed ORE (n = I or 2) before the patient was referred for ThUS. The patient was also referred to a surgeon for a rectal biopsy to confirm the diagnosis.
RESULTS Six patients
had difficulty voiding. referred for suspected metastatic disease of the prostate, mainly because of weight loss, back pain, and a suspicious prostatic finding at DRE (Table). Evaluation of the gastrointestinal tract showed that three patients had no gastrointestinal problems and that they complained about nonspecific problems such as chronic constipation. The two other patients had symptoms that might have indicated malignant tumors in the rectum: diarrhea alternating with Patient
4 was
constipation,
or fresh
blood
in their
stools. All patients
urologist TRUS.
underwent
who Three
ORE
referred
the
patients
also
by
patient
the
for
underwent
ORE by the family physician who referred them to the urologist. One patient underwent examination by a surgeon. Only two patients underwent examination by only one physician before TRUS. After the tumor was diagnosed, the urologist who performed TRUS (S.C.) also performed DRE and reported that in all
balloon.
By out, it was
the transducer in and to screen the rectum from
2 minutes.
the we
gland
localized
cm from the anus. All patients examination in this manner,
only
for
us to screen plane
him and was attached by means
used
the multiple-sector
us to screen
all planes. The transducer
6; accepted to S.C.
AND
Our study group consisted of seven patients aged 61-76 years (mean age, 69
now
received April reprint requests
Simon,
ultrasound (TRUS) is an imaging modality that enables diagnosis and staging of prostatic and rectal cancer (1,2). The cancers are acoustically less reflective than the surrounding normal tissue and yield a sonographic pattern consisting of a small number of weak echoes (3,4). The patients described herein were referred for TRUS examination to evaluate urobogic diseases. During TRUS, an unsuspected tumor of the rectum was found that had not been detected during digital rectal examination (DRE) performed by the referring physician. A meticulous DRE in which the physician concenhates not only on the anterior wall of the rectum that corresponds to the prostate but also on the posterobateral walls is important for discovery of rectal cancer in the early stages of the disease.
prostate
27, 1992; revision April 9. Address C RSNA, 1992
Dan
#{149}
RANSRETAL
enables
the Urology Institute, Beilinson Medical Center, Sadder School of Medicine, Tel Aviv University, Petah Tiqva 49100, IsraeL Received December 11, 1991; revision requested January
MD
ofRectal Carcinoma US for Prostatic Diseases’
This equipment
I From
Baniel,
1 to 14
underwent which takes
Abbreviations:
tion, ThUS
=
DRE transrectal
=
digital
rectal
examina-
US.
197
Clinical
Data in Seven
Patients
with
Rectal
Carcinoma
at TRUS
Findings
Physician Who
Symptoms
Patient No/Age
Gastrointes-
Depth
Performed
(y)
Urologic
1/72
Dysuria, frequency, nocturia, weak flow
Constipation
Dysuria, tuna,
None
None
Urologist
Mild
Chronic constipation
None
General practitioner, urologist
BPH
None
Weightloss,
Urologist
Normal
2/64
noc-
nocweak
tuna,
flow Dysuria; pected
4/62
Systemic None
sits-
Dysuria 2 y after TURP Dysuria
7/61
General
low
cancer at ORE Dysuria, nbctuna, Uigency
6/74
DRE
Location of Rectal Tumor
Urologic
prac-
BPH
Mild
Posterior
Dukes
C
12
Dukes
B
22
Dukes
C
33
Dukes
C
Lateral and posterior walls (4-B o’dock position)
27
Dukes
C
Lateral left wall Lateral right wall (7-11 o’dock position)
13
Dukes
B
17
Dukes
C
urologist
position) Posterior wall (6-9 o’clock
position) Posterior wall (4-7 o’clock position) pros-
Lateral
tate
of Adenocarcinoma
20
(5-7 o’clock
BPH
Rectal Tumor (mm)9
wall
titioner,
weakness,
prostate
5/71
Previous
weak
flow Dysuria,
3/76
tinal
Pathologic Stage
of
right
wall (1-6
back
o’clock
position)
pain Intermittent diarrhea and constipation; blood in stool None
None
General practitioner, urologist
Mild
None
Diarrhea, hemorrhoids,
None
Two urologists Surgeon, urologist
Normal prostate Mild BPH
BPH
anal
fissure
Note.-BPH = benign prostatic hypertrophy, TURP = transurethral 9Depth of rectal tumor below mucosa (from balloon wall).
1.
2.
Figures
1-3.
(1) Large
hypoechoic
tumor
on
the
3. right
side
into the rectal space because the inflated balloon hypoechoic tumor of the right rectal wall invades rectal wall. (3) Small hypoechoic tumor within the posterior fat.
protrude (2) Large
seven patients the tumors were easily palpated during DRE. A hypoechoic lesion was suspected to be rectal cancer in all seven patients
(Figs
i-3).
The
tumors
terior
side.
lient
4, the
and
6 o’clock
tumor
Radiology
#{149}
was
positions,
keeps
and
the
the space open.
all the rectal layers rectal wall invades
to the
of the gery.
distorts
anterior
rectum
and
The right seminal
on
the
adenocarcinoma
underwent
sur-
the
the
1
pos-
minute
of the
vesicle
right
enables
details
lumen.
especially
transducers not surprising this
tumor
does
not
is seen above the anterior invasion into the penrectal
gland,
resolution therefore
The
very close to the tumor.
modality
when
high-
are used. It is that in recent has
gained
great
popularity detection
visualization
of the
rectal
is situated
prostate
years,
DISCUSSION TRUS
symmetry
and the perirectal fat. The prostate all rectal layers and shows minimal
wall
had
circular
were
between
from
presses
All patients
large, and all were localized mainly on the posterior or lateral wall. In pa-
198
of the prostate.
resection
rectum
of
and
among physicians in the and staging of cancers of these organs and benign diseases of the prostate (5-7). We have used TRUS in our departOctober1992
ment during recent years lion of prostalic diseases. ity
is considered
and
precise
is an efficient
modern When
for evaluaThe modaland
diagnostic
effective
tool
in
urology.
TRUS is correctly used, a seclion with a maximum length of 14 cm, beginning from the anus, can be screened. TRUS provides a clear image of the rectal wall along its circumference, and a tumor less than 1 cm in diameter can be discovered without difficulty. Tumors of the rectum are characterized by a hypoechoic lesion that distorts the symmetry and the continuity of healthy layers. They do not protrude into the rectal space during examinalion with TRUS because the inflated balloon inserted in the recturn
keeps
the
space
open.
Whenever
the distention in barge tumors is noliceabbe, the balloon itself loses its symmetry. It is difficult to diagnose the many layers of the rectal wall in the tumor region, but it is easy to see invasion of the mucosa and muscular layers and perirectal fat infiltration. Physicians eases seem
who detect to concentrate
prostalic on the
dis-
prostate and seminal vesicles. This explains why the tumors were not found in the seven patients who underwent rectal examination, despite the barge size of the tumors and the fact that they were easily palpated after ThUS. Some patients not only had urinary symptoms but also had symptoms cupying
characteristic
of space-oc-
lesions of the rectum such as rectal bleeding, constipation, and diarrhea. The fact that we found preyously undiagnosed rectal tumors in seven patients convinced us that the physician should be aware of possible findings other than prostalic disease and therefore should examine all rec-
Volume
185
#{149} Number
1
tab walls at DRE performed for a urologic purpose. During sonographic imaging of prostatic and seminal vesides, it is valuable to also screen the rectum while one searches for a noticeable tumor. This is the advantage of the circular device that promises good imaging of the rectal wall. Recently, use of the section-screening transducer has increased the importance of complete screening of the rectum at the end of prostalic imaging. To screen the lateral and posterior walls of the rectum, it is recommended that the transducer be turned 1800 toward each side, along the bongitudinal axis. We do not perform TRUS for rectal screening. But as we perform TRUS for prostatic disorders, we scan the rectal wall when the probe is in the rectum; it takes only 2-3 minutes to do so. Of course, this cannot be compared with meticulous rectal scanning,
which
is lime-consuming
importance of a meticulous rectal examinalion of the whole rectal circumference, because haff of the rectal tumors are known to be within reach during DRE (9). At the same time, it is obvious from our study that some of the proximal rectal tumors are not detected during DRE. We believe that brief screening of the rectal walls can enable discovery of some of the undetected tumors. In our opinion, this short view of the rectal wall in the scanning field has to be an integral part of endorectal sonography. #{149} References 1.
Hildebrandt
2.
instrwnentation and clinical aspects. Colorectal Dis 1986; 1:207-230. Lee F, Gray JM, McLeary RD, et aL
Endorectal
ultrasound: hit J Pros-
tatic evaluation by transrectal sonography: criteria for diagnosis of early carcinoma. Radiology 1986; 158:91-95. 3.
but
logically can enable detection of smaller rectal lesions. Our suggestion to also image the rectum is not for early detection of rectal cancer, but for extension of the field of imaging in order to find noticeable rectal tumors. Whenever a rectal tumor is discovered during TRUS, it is recommended that, in addition to evaluation of scans obtained in the transverse plane, one use the multipbane transducer to evaluate the longitudinal plane of the rectum. The distance between the tumor edge and the anus should be known, because it is important in selection of the appropriate surgical procedure. Because the prevalence of rectal cancer is approximately 16 in 100,000 (8), it seems that the use of TRUS for screening in early detection of rectal cancer is not cost-effective and is lime-consuming. This emphasizes the
U.
4.
5.
Wang
KY, Kimmey
BristoL Rifkin
IntJ Colorectal MD, Wechsler
computed trasound orectal
6.
MB, Nyberg
DA,
et al.
Colorectal neoplasms: accuracy of US in demonstrating the depth of invasion. Radiology 1987; 165:827-829. BeynonJ, Mortensen NJ, Foy DM, Channer JL, VirjeeJ, Goddard P. Endorectal sonography: laboratory and dinical experience in
Senagore
Dis 1986; 1:212-215. BJ. A comparison of
tomography and endorectal ulin staging rectal cancer. Int J ColDis 1986;
1:219-223. jW, Senagore
A, Milsom
WI,, Scholten DJ, between intrarectal
P. Mazier
Zydbel P.
A comparison ultrasound and CT scanof experimental rectal hi-
7.
8. 9.
rung in staging mors.J Surg Res 1988; 44:522-526. Waizer
A, Zitron
5,
Ben
Baruch
D, BanielJ,
Wolloch Y, Dintsman M. Comparative study for preoperative staging of rectal cer. Dis Colon Rectum 1989; 32:53-56. Silverberg E. Cancer statistics. Cancer 1985; 35:19-35. Petersdorf RG, Adams RD, Baraunwald Isselbacher iq, MartinJG, Wilson JD. rison’s principles of internal medicine.
ed, vol 2. New Yorlc McGraw-Hill, 1763.
Radiology
can-
E, Har10th
1983;
199
#{149}
