DOI:10.2214/AJR.07.3067
AJR 2008; 191:186-189
© American Roentgen Ray Society
Sonography Transmission Gel as Endorectal Contrast Agent for Tumor Visualization in Rectal Cancer
Seung Ho Kim1,
Jeong Min Lee1,
Min Woo Lee2,
Gi Hyeon Kim3,
Joon Koo Han1 and
Byung Ihn Choi1
1 Department of Radiology, Seoul National University College of Medicine,
Yongon-dong 28, Chongno-gu, 110-744 Seoul, Korea.
2 Department of Radiology, Konkuk University School of Medicine, Seoul,
Korea.
3 Department of Radiology, Chung-Ang University Hospital, Seoul, Korea.
Received August 25, 2007;
accepted after revision January 14, 2008.
Address correspondence to J. M. Lee
(leejm{at}radcom.snu.ac.kr).
Abstract
OBJECTIVE. The purpose of our study is to show the usefulness and
safety of sonography transmission gel as an endorectal contrast agent in
preoperative rectal MRI for tumor visualization in rectal cancer.
CONCLUSION. Sonography transmission gel is an effective and safe
endorectal contrast agent for rectal MRI.
Keywords: MRI • rectal cancer • rectum • sonography transmission gel
Introduction
Optimal management of rectal cancer requires detailed preoperative planning
that includes assessment of the tumor extent and the depth of invasion
[1]. A variety of examinations
have been used for the preoperative planning of rectal cancer management
[2], including digital rectal
examination, endorectal sonography, CT, and MRI. However, thin-slice MRI is
increasingly being used because of its ability to show both tumor extent and
depth of invasion [3]. To
improve the diagnostic performance of MRI in lower T-staging of primary rectal
cancer, various materials have been used to induce rectal distention including
barium enema [4]; the
superparamagnetic iron oxide contrast agent, ferristene
[5]; methylcellulose
[6]; and warm water
[7]. The infusate should have
both adequate viscosity and good contrast to induce good distention and
visualization on MRI.
Sonography transmission gel is magnetically inert, semisolid, inexpensive,
and easy to handle. This agent has been used for many years in the dynamic
evaluation of the pelvic floor with MRI
[8]. To the best of our
knowledge, however, there has been only one study in which this agent was used
for evaluation of tumor response after chemoradiation therapy in patients with
rectal cancer [9]. The purpose
of this study was to determine the usefulness of sonography transmission gel
as an endorectal contrast agent for tumor visualization in rectal cancer.
Materials and Methods
This retrospective study was approved by our institutional review board,
and the principles of the Declaration of Helsinki were followed. However, we
did not obtain informed consent from each patient before the MRI examinations
because sonography transmission gel has been used for pelvic dynamic MRI for
several years. From January 2004 to June 2007, 60 patients (41 men, 19 women;
age range, 33–86 years; mean age, 62 years) with surgically proven
rectal cancer who had undergone preoperative MRI were enrolled in this
study.
MRI Technique
All MRI was performed on a 1.5-T super-conducting system (Signa Excite, GE
Healthcare) using a phased-array torso coil, and the coil was centered on the
hip joint to fully cover the rectum. One bisacodyl suppository (Dulcolax,
Boehringer Ingelheim) was inserted into the rectum for bowel preparation 10
hours before the MRI. To reduce colonic motility, 20 mg of scopolamine
butyl-bromide (Buscopan, Boehringer Ingelheim) was injected intramuscularly
before MRI as a pre-medication. Approximately 80–100 mL of sonography
transmission gel (Supersonic, Sungheung) was administered using an enema
syringe (Safti, Boin Medica) while the patient was on the MR table in the
right lateral decubitus position with the knees on the chest. The
administration was stopped immediately if the patient experienced intolerable
pain. After the administration, the patient was placed in a supine
position.
The MRI protocol was composed of T2-weighted fast spin-echo and T1-weighted
spin-echo sequences in each axial and sagittal plane with the following
parameters: For T2-weighted fast spin-echo, TR/TE, 4,500/107.5; echo-train
length, 16; slice thickness, 5.0 mm; gap, 1.0 mm; field of view, 240 mm;
matrix, 384 x 224; and number of excitations (NEX), 4. For T1-weighted
spin-echo, TR range/TE 500–600/11; matrix, 320 x 192; slice
thickness, 5.0 mm; gap, 1 mm; field of view, 240 mm; matrix, 320 x 192;
and NEX, 2. We also obtained contrast-enhanced T1-weighted spin-echo images
after administration of 0.1 mmol/kg of body weight of gadobenate dimeglumine
(MultiHance, Bracco).
Image Interpretation
Two gastrointestinal radiologists with 4 years of experience in rectal MRI
independently reviewed each set of axial and sagittal T2- and T1-weighted
images to assess the degree of tumor visualization and rectal distention using
predetermined criteria [7].
They assessed the tumor visualization using a 4-point scale. The conspicuity
of tumor margin was rated as follows: 1, tumor could not be identified; 2,
tumor was identified, but its intraluminal margin was not defined; 3, tumor
was identified, and its intraluminal margin was partially defined; and 4,
whole tumor margin was well defined
[7]. They also used a 4-point
scale to evaluate optimal rectal distention: 1, still collapsed throughout
entire rectum; 2, partially distended rectum with more than one collapsed
segment; 3, suboptimal distended rectum with one collapsed segment; and 4,
fully distended rectum without collapsed segment throughout entire rectum.
Pathologic evaluation of the gross speci men served as the reference
standard.
Statistical Analysis
On the basis of the surgical findings—tumor location and
morphology—the study population was divided into subgroups. The scores
for rectal distention and tumor visualization for each reader were averaged
and compared among the surgical subgroups using the Friedman test. All
statistical analyses were performed using InStat version 3.05 for Windows
(GraphPad Software).
View larger version (155K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1A —79-year-old man with pathologically proven distal rectal
cancer (stage T1). T2-weighted sagittal MR image shows evenly distributed
sonography transmission gel throughout entire rectum. Consequently, rectal
walls are delineated smoothly and continuously. This endorectal contrast agent
shows homogeneously higher signal intensity than urine. Lobulating polypoid
mass (arrow) is noted in distal rectum.
|
|
View larger version (156K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 1B —79-year-old man with pathologically proven distal rectal
cancer (stage T1). T2-weighted axial MR image shows that depth of invasion of
polypoid mass is confined to submucosa (arrow). Intact outer wall is
also noted.
|
|
Results
Successful administration of sonography transmission gel was achieved in
all patients except one (59/60; 98.3%) who was diagnosed with distal rectal
cancer. This patient complained of a feeling of impending incontinence, and
administration of sonography transmission gel was ceased.
The overall tumor visualization scores (3.68–3.95) were nearly
perfect for both reviewers. The comparison among the subgroups according to
location and morphology for both reviewers is summarized in
Table 1. The overall tumor
visualization scores did not differ significantly for both reviewers,
regardless of the location and the morphology (p > 0.05).
Discussion
Our study showed that rectal administration of sonography transmission gel
for rectal MRI effectively visualized rectal cancer in most cases (3.88 for
reviewer 1 and 3.77 for reviewer 2) without any complications (Figs.
1A,
1B,
2A,
2B,
3A,
3B). The overall tumor
visualization scores according to location and morphology in our study were
markedly higher than the results of the previous study, which used a similar
visualization score in patients with rectal cancer
[7]. Furthermore, sonography
transmission gel showed good patient tolerance (59/60; 98.3%). Other merits of
sonography transmission gel include its inert characteristic in the magnetic
field, high contrast on T2-weighted fast spin-echo imaging, the effective
distention of the rectal wall owing to its own semisolid state, the low cost
(less than 50 cents per patient), and the ease of manipulation.
View larger version (149K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 2A —70-year-old man with pathologically confirmed distal rectal
cancer (stage T2). T2-weighted sagittal MR image shows optimally distended
entire rectum. Focal artifacts are seen at interface between air bubble and
gel, but they do not interfere with tumor visualization. Differentiation of
rectal wall is well visualized in posterior wall because of enhanced contrast
between gel and rectal mucosa. Ulcerofungating mass (arrow) is noted
in anterior wall.
|
|
View larger version (153K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 2B —70-year-old man with pathologically confirmed distal rectal
cancer (stage T2). T2-weighted axial MR image shows that outer dark signal
intensity of rectum is obliterated (arrow), which suggests invasion
of muscularis propria.
|
|
View larger version (158K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 3A —25-year-old man with pathologically confirmed distal rectal
cancer (stage T3). T2-weighted sagittal MR image shows uniformly distended
entire rectum. Ulceroinfiltrative mass (arrow) in the posterior wall
is well visualized.
|
|
View larger version (146K):
[in this window]
[in a new window]
[as a PowerPoint slide]
|
Fig. 3B —25-year-old man with pathologically confirmed distal rectal
cancer (stage T3). T2-weighted axial MR image shows that mass penetrates
muscularis propria. Nodular extension (arrow) to perirectal fat is
also seen.
|
|
To assess the tumor extent of rectal cancer with MRI, adequate distention
of the rectum with good contrast between the tumor and rectal lumen is
required. Compared with other rectal contrast agents such as 5%
methylcellulose solution or warm water solution, sonography transmission gel
is simple and easy to handle and can be used in a smaller volume. Goh et al.
[6] reported a study describing
the usefulness of 5% methylcellulose solution as a rectal contrast agent;
however, use of that agent required the additional step of dissolving the
compound granules before the procedure. By contrast, in our study, effective
rectal wall distention was achieved using no more than 100 mL of sonography
transmission gel. Warm water creates an air–fluid level that can cause
susceptibility artifacts due to local magnetic field inhomogeneity at the
interface [6,
7], which can then result in a
limited capacity to evaluate rectal cancer located in the anterior wall.
In conclusion, sonography transmission gel is an effective and safe
endorectal contrast agent for rectal MRI in patients with rectal cancer.
Although the evaluation of diagnostic accuracy for the T-staging using this
agent is beyond the scope of this technical innovation article, it is
important to determine whether this agent can increase the T-staging accuracy,
and further studies will be needed.
References
- van Lingen CP, Zeebregts CJ, Gerritsen JJ, Mulder HJ, Mastboom WJ,
Klaase JM. Local recurrence of rectal cancer after total mesorectal excision
without preoperative radiotherapy. Int J Gastrointest
Cancer 2003; 34:129
–134[CrossRef][Medline]
- Mathur P, Smith JJ, Ramsey C, et al. Comparison of CT and MRI in
the pre-operative staging of rectal adenocarcinoma and prediction of
circumferential resection margin involvement by MRI. Colorectal
Dis 2003; 5:396
–401[CrossRef][Medline]
- Brown G, Richards CJ, Newcombe RG, et al. Rectal carcinoma:
thin-section MR imaging for staging in 28 patients.
Radiology 1999;211
: 215–222[Abstract/Free Full Text]
- Panaccione JL, Ros PR, Torres GM, Burton SS. Rectal barium in
pelvic MR imaging: initial results. J Magn Reson
Imaging 1991; 1:605
–607[Medline]
- Wallengren NO, Holtas S, Andren-Sandberg A, Jonsson E,
Kristoffersson DT, McGill S. Rectal carcinoma: double-contrast MR imaging for
pre-operative staging. Radiology 2000;215
: 108–114[Abstract/Free Full Text]
- Goh JS, Goh JP, Wansaicheong GK. Methylcellulose as a rectal
contrast agent for MR imaging of rectal carcinoma. AJR2002; 178:1145
–1146[Free Full Text]
- Kim MJ, Lim JS, Oh YT, et al. Preoperative MRI of rectal cancer
with and without rectal water filling: an intraindividual comparison.
AJR 2004; 182:1469
–1476[Abstract/Free Full Text]
- Morren GL, Balasingam AG, Wells JE, Hunter AM, Coates RH, Perry RE.
Triphasic MRI of pelvic organ descent: sources of measurement error.
Eur J Radiol 2005;54
: 276–283[CrossRef][Medline]
- Kim YH, Kim DY, Kim TH, et al. Usefulness of magnetic resonance
volumetric evaluation in predicting response to preoperative concurrent
chemoradiotherapy in patients with resectable rectal cancer. Int J
Radiat Oncol Biol Phys 2005;62
: 761–768[CrossRef][Medline]
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
|
|
 
S. H. Kim, J. M. Lee, S. H. Hong, G. H. Kim, J. Y. Lee, J. K. Han, and B. I. Choi
Locally Advanced Rectal Cancer: Added Value of Diffusion-weighted MR Imaging in the Evaluation of Tumor Response to Neoadjuvant Chemo- and Radiation Therapy
Radiology,
October 1, 2009;
253(1):
116 - 125.
[Abstract]
[Full Text]
[PDF]
|
|
|
Top
Abstract
Introduction
