Transcript 09.Intern Seminar_JR..

Right Lower Quadrant Pain: Value of the
Nonvisualized Appendix in Patients at
Multidetector CT
Suvranu Ganguli, MD, Vassilios Raptopoulos, MD,
Fabio Komlos, MD, Bettina Siewert, MD and
Jonathan B. Kruskal, MD, PhD
Radiology 2006;241: 175-180
MED96
蘇熙淵
Introduction
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The most common cause of acute abdominal emergency
requiring surgical intervention is acute appendicitis
Other causes of abdominal pain, however, can mimic
appendicitis, such as colitis, diverticulitis, pelvic
inflammatory disease, and renal calculi.
CT has become increasingly used in the work-up of right
lower quadrant pain.
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CT scans obtained for RLQ pain, the appendix is not
visualized. two recent reports, 13% &14 %
Nonvisualization of the appendix on transverse CT scans
may safely be used to exclude acute appendicitis if no
secondary CT findings of appendicitis are present. -Nikolaidis et al
advances in multidetector CT , enhance the visualization
of the appendix strengthen the confidence of negative
Purpose
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To retrospectively determine the value of the
nonvisualized appendix at multidetector computed
tomography (CT) in patients with acute right lower
quadrant pain in whom appendicitis was a consideration.
Materials & Methods
Patient Selection and Study Design
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Retrospective review of all consecutive abdominal CT
scans
April 29 to October 31, 2003.
ER record "right lower quadrant pain"
CT reports classified four categories
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positive for appendicitis,
negative for appendicitis (normal appendix and normal results),
alternative acute diagnosis other than appendicitis,
appendix not visualized.
Imaging Technique Protocol
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eight–detector row CT scanner (Lightspeed Ultra; GE Medical Systems,
Milwaukee, Wis).
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oral contrast agent (600–900 mL of barium sulfate ) 60–
90 minutes before scanning
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IV contrast (100–150 mL of ioversol ; rate 2.5 mL/sec),
60 seconds before scanning.
A single scan
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lung base to the symphysis pubis
1.25-mm collimation
Total in 10–15 seconds
routine 5-mm-thick continuous transverse sections &
continuous coronal sections
Additional thin sections /interactive multiplanar images
were not obtained
Image Analysis
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an abdominal imaging attending physician and a
radiology resident
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Normal appendix : <6 mm ;lacked a thickened enhancing
wall ;no intraluminal calcifications, no periappendical
stranding.
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appendicitis :thickened enhancing wall ;>8 mm. 6 ~8 mm
with periappendiceal stranding
Clinical Follow-up
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appendix was not visualized  retrospective chart review
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To those loss f/u after MBD, authors asked institutional
review board–approved questions to determine whether
they had appendicitis at the time of CT examination.
Statistical Analysis
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Descriptive statistics of the age and sex of the patients in
the four groups
x2 test for sex and t test for age , P<.05
statistical software (SPSS )
Results
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400 examinations, 132 (33.0%) male ;268 (67.0%)
ages : 16 ~ 88 yrs
All oral contrast ; IV contrast 27 (6.8%)
normal appendix /CT without for abdominal pain:
182 (45.5%)
79 patients (19.8%) with other causes
1.inflammatory bowel disease or
colitis ( 26),
7.pyelonephritis or renal infarction ( 3)
2.diverticulitis ( 15)
9volvulus ( 2)
3 obstructing nephrolithiasis (11),
10 ruptured ovarian cyst or dermoid ( 2)
4. acute cholecystitis ( 5)
11tubo-ovarian abscess ( 2)
5 typhilitis / mesenteric adenitis(4)
12.bladder outlet obstruction (1)
6.cancer (4)
13pelvic arteriovenous malformation (1).
8 small-bowel obstruction ( 3)
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80 (20.0 %) with Dx of acute appendicitis by CT
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59 patients (14.8% ) :appendix was not visualized
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9/59 not f/u , MBD in good condition & not return ER
3/59 (exploration /appendectomy) without finding in CT.
Pathology: no evidence
There was no statistically significant difference between
groups regarding mean age or sex
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50 could be f/u in 59 patients whose appendix was not
visualized:
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46 note; 4 questionnaire
49 without related S/S
49(98%) patients with a nonvisualized appendix who were
negative for appendicitis
1 return 15 wks later, acute appendicitis ; initially 11 days after
C/S, Dx: postoperative infection of unclear etiology ; 24hr IV
A/B
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80 with Dx of acute appendicitis in CT
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6 :Tx with A/B without op, improved
74 appendectomy:
70 confirm appendicitis;
1 no finding
3 appendix Ca, endometriosis, ruptured ovarian cyst
95% (70 / 74) patients with multidetector CT findings that
were positive for appendicitis
Discussion
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use of CT for RLQ pain  increased availability ;fast,
accurate, & operator independent.
an appendix that is visualized at CT and that has a normal
appearance can be used to exclude appendicitis
acute appendicitis (inflamed appendix):
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distended with fluid.
>8 mm without surrounding inflammation, >6 mm with
surrounding changes.
wall is usually thickened & increased mural enhancement with
IV contrast .
Appendicoliths & periappendiceal inflammation
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CT in Dx RLQ pain:
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sensitivity98%,
specificity99%,
positive predictive value97%,
negative predictive98%
This study: positive: 95%
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Nonvisualization appendix :15% of the scans in this study
Uncomfortable for discharging : leads to increased obs
time & admission
This study, high percentage (98%) of negative allow to
exclude appendicitis when the appendix is not visualized
at CT.
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The absence of a distinctly visualized appendix in the
right lower quadrant and the absence of secondary
findings can be used to exclude appendicitis. —
Nikolaidis
Similarities: retrospective; multidetectorCT.
Differences:
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No of nonvisualized with f/u ;
Dr for image Dx,
No of loss f/u (hospital records & interviews)
group
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Improve identify appendix: contrast, focused scan
Protocol in this study is optimal for D/D
Imaging protocol use in susp appendicitis: contrast agents
are routinely given with 79%IV, 82% oral, and 32%rectal
in practice ,most common CT oral & IV contrast
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P’t with nonvisualized appendix had surgery
according :history, PE, lab
CT scans nonvisualized appendix highly correspond to
negative for appendicitis
Clinicians should be more comfortable with conservative
care in this group of patients.
Limitation
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the retrospective nature of follow-up
15% of patients were lost to follow-up
Conclusion
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Patients with right lower quadrant pain that is
unexplained at multidetector CT, a nonvisualized
appendix is a reliable predictor of the absence of
acute appendicitis.
Thanks for your attention!!