1265
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Acute
Appendicitis
Value of Sonography Perforation .
Shawn Marilyn Cheryl
P. QuiIIin1 J. Siegel1 M. Coffin2
:
:
CONCLUSION. submucosal AJR
1 , 1 992: accepted
after
revision
Presented in part at the annual meeting of the American Institute of Ultrasound in Medicine, San Diego, CA, March 1992. 1 The Mallinckrodt Institute of Radiology. Washington University School of Medicine, 510 5. Kingshighway Blvd., St. Louis, MO 631 10. Address reprint requests to M. J. Siegel. 2 Department of Pathology, Washington University School ofMedicine, 5i0 5. Kingshighway Blvd.,
St. Louis, MO
63i 10.
0361 -803X/92/i 0
American
Roentgen
Ray Society
:
Our results
appendicitis.
indicate
that sonography
The best predictors
layer and the presence
i59:i265-i268,
December
can be helpful in the diagnosis of are absence of the echogenic fluid collection.
of perforation
of a loculated 1992
Graded-compression sonography of the right lower quadrant using a highresolution, linear-array transducer has been shown to be a useful technique for diagnosing appendicitis, with a sensitivity between 80% and 95% [1 -8]. Recently, attempts have been made to differentiate between nonperforating and perforating appendicitis by using sonography [6, 9]. Puylaert et al. [6] reported a sensitivity of 29% for sonography in diagnosing perforating appendicitis. A more recent investigation by Borushok et al. [9] showed that no single sonographic finding was sensitive in diagnosing perforation, but that when a combination of findings was used, the sensitivity of sonography for diagnosing appendiceal perforation increased to 86%. Both these studies evaluated mainly adult patients. In a small series, Vignault et al. [8] described one sonographic finding (diffuse hypoechogenicity) that appeared to be highly suggestive of perforation in children. To better determine the value of sonography in distinguishing between nonperforating and perforating appendicitis in children, we reviewed the sonographic findings in 71 children with appendicitis, 26 of whom had appendiceal perforation.
Materials
596-i 265
in Detecting
OBJECTIVE. We determined the sonographic features of perforating appendicitis in children in order to determine the best criteria for establishing the diagnosis. MATERIALS AND METHODS. Sonograms of the right lower quadrants of 71 children with proved appendicitis were reviewed to determine the value of sonography in distinguishing between nonperforating and perforating appendicitis. The sonographic signs evaluated included the presence or absence of an appendix, an echogenic submucosal layer, increased periappendiceal echogenicity, free or loculated periappendiceal or pelvic fluid collections, and appendicoliths. The sonographic findings were correlated with the surgical and pathologic findings. RESULTS. Forty-five patients had nonperforating appendicitis, and 26 had perforating appendicitis. A sonographically visible appendix was present in all patients with nonperforating appendicitis and in 10 (38%) of 26 patients with perforation. An echogenic submucosa was noted in 27 (60%) of 45 patients with uncomplicated appendicitis but in only three (30%) of 10 patients with a visible appendix and perforating appendicitis (p < .05). In 19 of 26 patients with perforating appendicitis, sonography showed Ioculated periappendiceal or pelvic fluid collections; no patient with nonperforating appendicitis had a loculated fluid collection (p < .05). No statistically significant association was found between the presence or absence of perforation and free pelvic fluid, prominent periappendiceal fat, or an appendicolith. perforating
Received June JuIy7, 1992.
‘
in Children:
and Methods
We retrospectively
reviewed
the sonograms
of 79 children with surgically
proved appen-
Downloaded from www.ajronline.org by 74.33.139.96 on 10/19/15 from IP address 74.33.139.96. Copyright ARRS. For personal use only; all rights reserved
1266
QUILLIN
ET AL.
AJR:159,
Fig. 1.-Nonperforating
December
1992
appendicitis.
A, Longitudinal sonogram pressible, tubular appendix submucosal layer (arrows)
shows a noncomwith an echogenic and a hypoechoic
center. B, Transverse sonogram in another patient shows a target appearance with a hypoechoic lumen containing scattered debris, a more echogenic submucosa (arrows), and hypoechoic wall.
dicitis 1 991
who were examined All sonograms were
.
between January 1988 and December obtained with a 5-MHz linear-array trans-
by using the graded-compression technique described by Puylaert [5]. Images of the right lower quadrant were obtained in longitudinal and transverse planes. Surgery was performed within 36 hr of the sonographic examination in all but two patients.
test was done
features
to evaluate
in diagnosing
the usefulness
of individual
sonographic
perforation.
ducer
Seventy-one
patients
had abnormal
shown to have appendicitis girls,
ranging
from
sonographic
at surgery.
1 9 months
findings
and were
There were 43 boys and 28
to 18 years
old (mean
age, 1 1 years).
Of the 26 patients with appendiceal perforations, 15 were boys and 1 1 were girls, ranging in age from 19 months to 17 years (mean, 10 years). In eight patients, the results of sonography were falsely negative, and these patients were excluded from the study. None of these patients had perforating appendicitis. Obesity accounted for the difficulty in identifying appendicitis by sonography in one of the eight patients. because
of
studies
Adequate
severe
graded
had no obvious
The sonograms surgical
to
could
not be achieved
The other false-negative
explanation.
were reviewed
or pathologic
attention
compression
pain in two patients.
findings.
the presence
blindly without
Images
or absence
were
knowledge
evaluated
of an appendix,
submucosal layer, increased periappendiceal loculated periappendiceal or other pelvic
of the
with
specific
an echogenic
echogenicity, free or fluid collections, and
appendicoliths.
Surgical and pathologic reports of each tively reviewed for the presence or absence
patient were of perforation,
retrospecabscess,
and appendicoliths, and those results were compared with the sonographic findings. Statistical analysis with a Fisher exact two-tailed
TABLE 1: Sonographic Findings Nonperforating Appendicitis
in Perforating
and
No. (%) of Patients Sonographic
Findings
Nonperforating
(n=45) Visible
appendix
Echogenic
submucosa
Hypoechoic appendix Loculated pericecal fluid Free intraperitoneal fluid
Increased genicity Appendicolith
periappendiceal
(n=26)
45 (100)
10 (38)
27
(60)
18
(40)
3 (30) 7 (70) 1 9 (73)
0 14
echo-
Perforating
(0) (31)
1 3 (50)
6
(1 3)
8 (31)
8
(1 8)
8 (31)
Results The sonographic findings are summarized in Table i Fortyfive patients had nonperforating appendicitis, and 26 had perforating appendicitis. A visible appendix with a diameter of greater than 6 mm was seen in all 45 patients with nonperforating appendicitis and in 1 0 (38%) of 26 patients with perforation. An echogenic submucosa was visualized in 27 (60%) of 45 patients with uncomplicated appendicitis (Fig. 1) and in three of 1 0 patients with perforating appendicitis and a sonographically recognizable appendix (p < .05). The presence of the echogenic submucosa produced a target sign on transverse sonograms, characterized by a hypoechoic center representing intraluminal fluid or pus, a hyperechoic submucosal layer, and a hypoechoic muscular rim. A diffusely hypoechoic appendix with or without scattered internal echoes but without an echogenic submucosa was seen in 18 of 45 patients with nonperforating appendicitis (Fig. 2) and in seven of 1 0 patients with perforating appendicitis and a sonographically identifiable appendix. Loculated periappendiceal or pelvic fluid collections were seen in 1 9 (73%) of 26 patients with perforation (Figs. 3 and 4) and in none of the 45 patients without perforation (p < .05). Free fluid in the right lower quadrant or pelvis was seen in 1 4 (31 %) of 45 patients with nonperforating appendicitis and in 1 3 (50%) of 26 patients with perforation. Prominent periappendiceal echogenicity (Fig. 5) and appendicoliths were noted in six (1 3%) and eight (1 8%) patients without perforation, respectively. In patients with perforation, prominent periappendiceal echogenicity and appendicoliths were noted in eight patients (31 %) each. These differences were not statistically significant. On gross examination, the nonperforated appendix usually was characterized by congestion and serosal hyperemia. After perforation, the appendix was distorted and covered by a purulent exudate. Microscopically, the changes ranged from minimal inflammation of the mucosa and submucosa to necrosis and destruction of these layers and the wall. Appendi.
AJR:159,
December
SONOGRAPHY
1992
OF ACUTE
APPENDICITIS
IN CHILDREN
1267
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Fig. 2.-Nonperforating appendicitis. Longitudinal sonogram shows a dilated appendix (arrows) with a hypoechoic lumen. Note loss of echogenic submucosa. During surgery, distal tip was found to be grossly distended and inflamed without evidence of perforation.
Fig. 3.-Perforated
appendix
with periappen-
diceal fluid. Longitudinal sonogram shows an irregular, poorly defined appendix (arrows). A noncompressible fluid collection (F) is noted adjacent to appendiceal tip. Perforated appendix with a periappendiceal abscess was found dur-
ing surgery.
Fig. 4.-Perforating nal sonogram shows
appendicitis. Longitudia rounded, noncompressible fluid collection (arrows) in right lower quadrant. No appendix was identifiable at sonography. Pencecal abscess was found during surgery.
Fig. 5.-Perforated appendix. Longitudinal sonogram shows a diffusely hypoechoic appendix, loss of echogenic submucosa, and echogenic periappendiceal fat (arrows). Acute
appendicitis
with a perforated
tip and periappen-
diceal phlegmon were noted during surgery. Echogenic focus (arrowhead) in appendiceal tip represented an appendicolith.
coliths were found in eight patients 1 5 patients with perforation.
without
perforation
and in
Discussion High-resolution sonography with graded compression has proved to be a reliable technique for establishing the diagnosis of appendicitis in adults and children. However, the usefulness of sonography in the diagnosis of perforating appendicitis is more controversial, with its relatively low sensitivity of 29% reported in a series by Puylaert et al. [6] and its relatively high sensitivity of 86% reported by Borushok et al. [9]. Appendiceal perforation was seen in 13-30% of children, with rates as high as 90% in infants [1 0, 1 1 ]. The 38% frequency of perforation in this series is, therefore, not unexpected. Identification of appendiceal perforation is important because it can alter clinical management. Prompt appendectomy is the treatment of choice in patients with nonperforating appendicitis or small perforations. However, in patients with periappendiceal phlegmon (i.e., an indurated soft-tissue mass without drainable pus) or relatively small periappendiceal abscesses, conservative management with antibiotic therapy followed by appendectomy at a later time through a cleaner
surgical field may be desirable. In patients with large or welldefined appendiceal abscesses, percutaneous catheter drainage may be preferred to early surgery [1 2, 13]. Our study confirms the value of sonography in identifying abnormalities in patients with perforation. In our series, an echogenic mucosa was visualized in 60% of patients with uncomplicated appendicitis and in 30% of patients with a visible appendix and perforating appendicitis. Conversely, loss of the echogenic layer of the submucosa was seen in 40% of patients with nonperforating appendicitis and 70% of patients with perforating appendicitis and a visible appendix. It has been postulated that the loss of the sonographic echogenic submucosa reflects extensive submucosal necrosis that predisposes to perforation [9]. On the basis of an observed absence of echogenic submucosa, we found the sensitivity of sonography in perforated appendicitis to be similar to that found by Vignault et al. [8], who reported loss of the submucosa in 25% of children with nonperforating appendicitis and in 75% of children with perforating appendicitis. Our study also confirms the data of Borushok et al. [9], who reported a 60% sensitivity of sonography in the diagnosis of perforating appendicitis in patients with a visible appendix without an echogenic lining.
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i 268
QUILLIN
Loculated periappendiceal or pelvic fluid was seen in 73% of our patients with perforation and was 1 00% specific for the diagnosis. The loculated fluid collections varied in size from 2 to 1 2 cm in diameter, were often round and complex, and had mass effect on adjacent structures. Borushok et al. [9] reported that the finding of loculated pericecal fluid had a sensitivity of 41% and a specificity of 1 00% for the diagnosis of perforating appendicitis in their primarily adult series. The increased frequency of loculated fluid in our patients compared with that found in the study by Borushok et al. may be attributable to the younger age and the higher perforation rate in our study group. Prominent periappendiceal echogenicity occurred in 13% of patients without appendiceal perforation and in 31 % of patients with appendiceal perforation in our series. Borushok et al. [9] reported prominent pericecal fat in 50% of their patients with perforation and suggested that it represented inflamed mesenteric or omental fat. The low frequency of periappendiceal echogenicity in our study may reflect the paucity of perivisceral fat in younger children. The presence offree fluid in the right lower quadrant or culde-sac and appendicoliths were not specific for perforation and were seen in children both with and without perforation in our series. Free fluid was seen in 50% of our patients with perforation and in 31% of patients without perforation. Appendicoliths were noted in 18% of patients with uncomplicated appendicitis and in 31 % of patients with perforating appendicitis. The differences were not statistically significant. Borushok et al. [9] also found no statistically significant correlation between the presence of free fluid or appendicoliths and appendiceal perforation. We found appendicoliths in children with perforating appendicitis more often on pathologic specimens than on sonograms.
ET AL.
AJR:159,
December
1992
In our experience, the appendix is visible on sonograms in 70% of children with appendicitis. The absence of the echogenic submucosal layer and the presence of a loculated fluid collection are the most conclusive sonographic findings of perforating appendicitis. REFERENCES 1. Abu-Yousef MM, Bleicher JJ, Maher JW, Urdaneta LF, Franken EA Jr, Metcalf AM. High-resolution sonography of acute appendicitis. AJR 1987;i49:53-58
2. Gaensler EHL, Jeffrey RB, Laing FC, Townsend RR. Sonography in patients with suspected acute appendicitis: value in establishing altemative diagnoses. AJR 1989:152:49-51 3. Jeffrey RB, Laing FC, Lewis FR. Acute appendicitis: high resolution realtime US findings. Radiology 1987:163:11-14 4. Jeffrey RB, Laing FC, Townsend AR. Acute appendicitis: sonographic criteria based on 250 cases. Radiology 1988:167:327-329 5. Puylaert JCBM. sion. Radiology
Acute appendicitis:
US evaluation
using
graded
compres-
1986;158:355-360 6. Puylaert JCBM, Rutgers RB, Lalisang RI, et al. A prospective study of ultrasonography in the diagnosis of appendicitis. N EngI J Med i987;3i7:666-669
7. Siegel MJ, Card C, Surratt S. Ultrasonography children.
JAMA
of acute abdominal pain in
i991;266:1987-1989
8. Vignault F, Filitarault D, Brandt ML, Garel L, Grignon A, Ouimet A. Acute appendicitis
in children:
evaluation
with US. Radiology
1990;i76:501-504
9. Borushok KF, Jeffrey RB, Laing FC, Townsend AR. Sonographic diagnosis of perforation in patients with acute appendicitis. AJR i990;i54:275-278 10. Dehner LP, ed. Pediatric surgicalpathology. Baltimore: Williams & Wilkins, i987:390-391
i 1 . Joffe N. Radiology Clin Radiol NucI Med
of acute appendicitis
and its complications.
i2. Jeffrey RB, Tolentino CS, Federle MP, Laing FC. Percutaneous of periappendiceal
Crit Rev
1975:6:97-160 abscesses:
review
of 20
patients.
AJR
drainage 1987;i49:
59-62 13. Jeffrey
RB,
Federle
masses: CT-directed Radiology
MP,
Tolentino
management
1988:167:13-16
CS.
Periappendiceal
and clinical outcome
inflammatory
in 70 patients.
Downloaded from www.ajronline.org by 74.33.139.96 on 10/19/15 from IP address 74.33.139.96. Copyright ARRS. For personal use only; all rights reserved
Acute
Appendicitis
Value of Sonography Perforation .
Shawn Marilyn Cheryl
P. QuiIIin1 J. Siegel1 M. Coffin2
:
:
CONCLUSION. submucosal AJR
1 , 1 992: accepted
after
revision
Presented in part at the annual meeting of the American Institute of Ultrasound in Medicine, San Diego, CA, March 1992. 1 The Mallinckrodt Institute of Radiology. Washington University School of Medicine, 510 5. Kingshighway Blvd., St. Louis, MO 631 10. Address reprint requests to M. J. Siegel. 2 Department of Pathology, Washington University School ofMedicine, 5i0 5. Kingshighway Blvd.,
St. Louis, MO
63i 10.
0361 -803X/92/i 0
American
Roentgen
Ray Society
:
Our results
appendicitis.
indicate
that sonography
The best predictors
layer and the presence
i59:i265-i268,
December
can be helpful in the diagnosis of are absence of the echogenic fluid collection.
of perforation
of a loculated 1992
Graded-compression sonography of the right lower quadrant using a highresolution, linear-array transducer has been shown to be a useful technique for diagnosing appendicitis, with a sensitivity between 80% and 95% [1 -8]. Recently, attempts have been made to differentiate between nonperforating and perforating appendicitis by using sonography [6, 9]. Puylaert et al. [6] reported a sensitivity of 29% for sonography in diagnosing perforating appendicitis. A more recent investigation by Borushok et al. [9] showed that no single sonographic finding was sensitive in diagnosing perforation, but that when a combination of findings was used, the sensitivity of sonography for diagnosing appendiceal perforation increased to 86%. Both these studies evaluated mainly adult patients. In a small series, Vignault et al. [8] described one sonographic finding (diffuse hypoechogenicity) that appeared to be highly suggestive of perforation in children. To better determine the value of sonography in distinguishing between nonperforating and perforating appendicitis in children, we reviewed the sonographic findings in 71 children with appendicitis, 26 of whom had appendiceal perforation.
Materials
596-i 265
in Detecting
OBJECTIVE. We determined the sonographic features of perforating appendicitis in children in order to determine the best criteria for establishing the diagnosis. MATERIALS AND METHODS. Sonograms of the right lower quadrants of 71 children with proved appendicitis were reviewed to determine the value of sonography in distinguishing between nonperforating and perforating appendicitis. The sonographic signs evaluated included the presence or absence of an appendix, an echogenic submucosal layer, increased periappendiceal echogenicity, free or loculated periappendiceal or pelvic fluid collections, and appendicoliths. The sonographic findings were correlated with the surgical and pathologic findings. RESULTS. Forty-five patients had nonperforating appendicitis, and 26 had perforating appendicitis. A sonographically visible appendix was present in all patients with nonperforating appendicitis and in 10 (38%) of 26 patients with perforation. An echogenic submucosa was noted in 27 (60%) of 45 patients with uncomplicated appendicitis but in only three (30%) of 10 patients with a visible appendix and perforating appendicitis (p < .05). In 19 of 26 patients with perforating appendicitis, sonography showed Ioculated periappendiceal or pelvic fluid collections; no patient with nonperforating appendicitis had a loculated fluid collection (p < .05). No statistically significant association was found between the presence or absence of perforation and free pelvic fluid, prominent periappendiceal fat, or an appendicolith. perforating
Received June JuIy7, 1992.
‘
in Children:
and Methods
We retrospectively
reviewed
the sonograms
of 79 children with surgically
proved appen-
Downloaded from www.ajronline.org by 74.33.139.96 on 10/19/15 from IP address 74.33.139.96. Copyright ARRS. For personal use only; all rights reserved
1266
QUILLIN
ET AL.
AJR:159,
Fig. 1.-Nonperforating
December
1992
appendicitis.
A, Longitudinal sonogram pressible, tubular appendix submucosal layer (arrows)
shows a noncomwith an echogenic and a hypoechoic
center. B, Transverse sonogram in another patient shows a target appearance with a hypoechoic lumen containing scattered debris, a more echogenic submucosa (arrows), and hypoechoic wall.
dicitis 1 991
who were examined All sonograms were
.
between January 1988 and December obtained with a 5-MHz linear-array trans-
by using the graded-compression technique described by Puylaert [5]. Images of the right lower quadrant were obtained in longitudinal and transverse planes. Surgery was performed within 36 hr of the sonographic examination in all but two patients.
test was done
features
to evaluate
in diagnosing
the usefulness
of individual
sonographic
perforation.
ducer
Seventy-one
patients
had abnormal
shown to have appendicitis girls,
ranging
from
sonographic
at surgery.
1 9 months
findings
and were
There were 43 boys and 28
to 18 years
old (mean
age, 1 1 years).
Of the 26 patients with appendiceal perforations, 15 were boys and 1 1 were girls, ranging in age from 19 months to 17 years (mean, 10 years). In eight patients, the results of sonography were falsely negative, and these patients were excluded from the study. None of these patients had perforating appendicitis. Obesity accounted for the difficulty in identifying appendicitis by sonography in one of the eight patients. because
of
studies
Adequate
severe
graded
had no obvious
The sonograms surgical
to
could
not be achieved
The other false-negative
explanation.
were reviewed
or pathologic
attention
compression
pain in two patients.
findings.
the presence
blindly without
Images
or absence
were
knowledge
evaluated
of an appendix,
submucosal layer, increased periappendiceal loculated periappendiceal or other pelvic
of the
with
specific
an echogenic
echogenicity, free or fluid collections, and
appendicoliths.
Surgical and pathologic reports of each tively reviewed for the presence or absence
patient were of perforation,
retrospecabscess,
and appendicoliths, and those results were compared with the sonographic findings. Statistical analysis with a Fisher exact two-tailed
TABLE 1: Sonographic Findings Nonperforating Appendicitis
in Perforating
and
No. (%) of Patients Sonographic
Findings
Nonperforating
(n=45) Visible
appendix
Echogenic
submucosa
Hypoechoic appendix Loculated pericecal fluid Free intraperitoneal fluid
Increased genicity Appendicolith
periappendiceal
(n=26)
45 (100)
10 (38)
27
(60)
18
(40)
3 (30) 7 (70) 1 9 (73)
0 14
echo-
Perforating
(0) (31)
1 3 (50)
6
(1 3)
8 (31)
8
(1 8)
8 (31)
Results The sonographic findings are summarized in Table i Fortyfive patients had nonperforating appendicitis, and 26 had perforating appendicitis. A visible appendix with a diameter of greater than 6 mm was seen in all 45 patients with nonperforating appendicitis and in 1 0 (38%) of 26 patients with perforation. An echogenic submucosa was visualized in 27 (60%) of 45 patients with uncomplicated appendicitis (Fig. 1) and in three of 1 0 patients with perforating appendicitis and a sonographically recognizable appendix (p < .05). The presence of the echogenic submucosa produced a target sign on transverse sonograms, characterized by a hypoechoic center representing intraluminal fluid or pus, a hyperechoic submucosal layer, and a hypoechoic muscular rim. A diffusely hypoechoic appendix with or without scattered internal echoes but without an echogenic submucosa was seen in 18 of 45 patients with nonperforating appendicitis (Fig. 2) and in seven of 1 0 patients with perforating appendicitis and a sonographically identifiable appendix. Loculated periappendiceal or pelvic fluid collections were seen in 1 9 (73%) of 26 patients with perforation (Figs. 3 and 4) and in none of the 45 patients without perforation (p < .05). Free fluid in the right lower quadrant or pelvis was seen in 1 4 (31 %) of 45 patients with nonperforating appendicitis and in 1 3 (50%) of 26 patients with perforation. Prominent periappendiceal echogenicity (Fig. 5) and appendicoliths were noted in six (1 3%) and eight (1 8%) patients without perforation, respectively. In patients with perforation, prominent periappendiceal echogenicity and appendicoliths were noted in eight patients (31 %) each. These differences were not statistically significant. On gross examination, the nonperforated appendix usually was characterized by congestion and serosal hyperemia. After perforation, the appendix was distorted and covered by a purulent exudate. Microscopically, the changes ranged from minimal inflammation of the mucosa and submucosa to necrosis and destruction of these layers and the wall. Appendi.
AJR:159,
December
SONOGRAPHY
1992
OF ACUTE
APPENDICITIS
IN CHILDREN
1267
Downloaded from www.ajronline.org by 74.33.139.96 on 10/19/15 from IP address 74.33.139.96. Copyright ARRS. For personal use only; all rights reserved
Fig. 2.-Nonperforating appendicitis. Longitudinal sonogram shows a dilated appendix (arrows) with a hypoechoic lumen. Note loss of echogenic submucosa. During surgery, distal tip was found to be grossly distended and inflamed without evidence of perforation.
Fig. 3.-Perforated
appendix
with periappen-
diceal fluid. Longitudinal sonogram shows an irregular, poorly defined appendix (arrows). A noncompressible fluid collection (F) is noted adjacent to appendiceal tip. Perforated appendix with a periappendiceal abscess was found dur-
ing surgery.
Fig. 4.-Perforating nal sonogram shows
appendicitis. Longitudia rounded, noncompressible fluid collection (arrows) in right lower quadrant. No appendix was identifiable at sonography. Pencecal abscess was found during surgery.
Fig. 5.-Perforated appendix. Longitudinal sonogram shows a diffusely hypoechoic appendix, loss of echogenic submucosa, and echogenic periappendiceal fat (arrows). Acute
appendicitis
with a perforated
tip and periappen-
diceal phlegmon were noted during surgery. Echogenic focus (arrowhead) in appendiceal tip represented an appendicolith.
coliths were found in eight patients 1 5 patients with perforation.
without
perforation
and in
Discussion High-resolution sonography with graded compression has proved to be a reliable technique for establishing the diagnosis of appendicitis in adults and children. However, the usefulness of sonography in the diagnosis of perforating appendicitis is more controversial, with its relatively low sensitivity of 29% reported in a series by Puylaert et al. [6] and its relatively high sensitivity of 86% reported by Borushok et al. [9]. Appendiceal perforation was seen in 13-30% of children, with rates as high as 90% in infants [1 0, 1 1 ]. The 38% frequency of perforation in this series is, therefore, not unexpected. Identification of appendiceal perforation is important because it can alter clinical management. Prompt appendectomy is the treatment of choice in patients with nonperforating appendicitis or small perforations. However, in patients with periappendiceal phlegmon (i.e., an indurated soft-tissue mass without drainable pus) or relatively small periappendiceal abscesses, conservative management with antibiotic therapy followed by appendectomy at a later time through a cleaner
surgical field may be desirable. In patients with large or welldefined appendiceal abscesses, percutaneous catheter drainage may be preferred to early surgery [1 2, 13]. Our study confirms the value of sonography in identifying abnormalities in patients with perforation. In our series, an echogenic mucosa was visualized in 60% of patients with uncomplicated appendicitis and in 30% of patients with a visible appendix and perforating appendicitis. Conversely, loss of the echogenic layer of the submucosa was seen in 40% of patients with nonperforating appendicitis and 70% of patients with perforating appendicitis and a visible appendix. It has been postulated that the loss of the sonographic echogenic submucosa reflects extensive submucosal necrosis that predisposes to perforation [9]. On the basis of an observed absence of echogenic submucosa, we found the sensitivity of sonography in perforated appendicitis to be similar to that found by Vignault et al. [8], who reported loss of the submucosa in 25% of children with nonperforating appendicitis and in 75% of children with perforating appendicitis. Our study also confirms the data of Borushok et al. [9], who reported a 60% sensitivity of sonography in the diagnosis of perforating appendicitis in patients with a visible appendix without an echogenic lining.
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i 268
QUILLIN
Loculated periappendiceal or pelvic fluid was seen in 73% of our patients with perforation and was 1 00% specific for the diagnosis. The loculated fluid collections varied in size from 2 to 1 2 cm in diameter, were often round and complex, and had mass effect on adjacent structures. Borushok et al. [9] reported that the finding of loculated pericecal fluid had a sensitivity of 41% and a specificity of 1 00% for the diagnosis of perforating appendicitis in their primarily adult series. The increased frequency of loculated fluid in our patients compared with that found in the study by Borushok et al. may be attributable to the younger age and the higher perforation rate in our study group. Prominent periappendiceal echogenicity occurred in 13% of patients without appendiceal perforation and in 31 % of patients with appendiceal perforation in our series. Borushok et al. [9] reported prominent pericecal fat in 50% of their patients with perforation and suggested that it represented inflamed mesenteric or omental fat. The low frequency of periappendiceal echogenicity in our study may reflect the paucity of perivisceral fat in younger children. The presence offree fluid in the right lower quadrant or culde-sac and appendicoliths were not specific for perforation and were seen in children both with and without perforation in our series. Free fluid was seen in 50% of our patients with perforation and in 31% of patients without perforation. Appendicoliths were noted in 18% of patients with uncomplicated appendicitis and in 31 % of patients with perforating appendicitis. The differences were not statistically significant. Borushok et al. [9] also found no statistically significant correlation between the presence of free fluid or appendicoliths and appendiceal perforation. We found appendicoliths in children with perforating appendicitis more often on pathologic specimens than on sonograms.
ET AL.
AJR:159,
December
1992
In our experience, the appendix is visible on sonograms in 70% of children with appendicitis. The absence of the echogenic submucosal layer and the presence of a loculated fluid collection are the most conclusive sonographic findings of perforating appendicitis. REFERENCES 1. Abu-Yousef MM, Bleicher JJ, Maher JW, Urdaneta LF, Franken EA Jr, Metcalf AM. High-resolution sonography of acute appendicitis. AJR 1987;i49:53-58
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