Content uploaded by Miguel Jose Francisco Neto
Author content
All content in this area was uploaded by Miguel Jose Francisco Neto
Content may be subject to copyright.
einstein. 2005; 3(3):185-189
185Ultrasonography in the diagnosis of acute appendicitis
Ultrasonography in the diagnosis of acute appendicitis
Ultra-sonografia no diagnóstico de apendicite aguda
Luciano Augusto Botter1, George Rachid Oliveira2, Janos Lima de Farias3, Alexandre Maurano4,
Rodrigo Gobbo Garcia5, Marcos Roberto de Queiroz6, Marcelo Rocha Silva7,
Miguel José Francisco Neto8, Marcelo Buarque Gusmão Funari9
ORIGINAL ARTICLE
ABSTRACT
Objective: To evaluate the role of sonography in diagnosis of
acute appendicitis, with an emphasis on early evolution cases.
Methods: From 240 cases with the diagnosis of appendicitis, a
retrospective study of 149 patients submitted to appendicectomy
at the Hospital Israelita Albert Einstein, in 2002, was carried out.
The appendix of these 149 patients was visualized in a
preoperative sonography and the diagnosis was confirmed by
histological examination. Patients were distributed into two
groups - initial and advanced - according to the measure of the
largest external diameter of the appendix. The statistical data
analysis included demographic information (sex and age) and
direct and indirect signs of acute appendicitis. Results: There
were more cases of acute appendicitis in the groups aged 10-30
years, mean age of 18.3 years in the initial group and 26.4 years
in the advanced group. There was no statistically significant
difference regarding sex. The advanced group presented 4.5%
of false-positive results and the initial group, 23.1%. Among the
direct signs, non-compressibility of the appendix stood out and
was observed in more than half cases; with regard to indirect
signs, hyperechogenicity of periappendiceal tissues was
observed in up to 75% of cases in both groups. Conclusion: There
was a statistically significant difference in false-positive cases,
which were more often observed in the initial group. Therefore,
sonographic follow-up is recommended in these cases.
Keywords: Appendicitis/diagnosis; Appendicitis/radiography;
Appendicitis/ultrasonography
RESUMO
Objetivo: Avaliar o papel da ultra-sonografia no diagnóstico da apendicite
aguda com ênfase nos casos de evolução precoce. Métodos: Foi
realizado estudo retrospectivo em 149 pacientes selecionados a partir
de 240 casos com o diagnóstico de apendicite no Hospital Israelita
Albert Einstein. Esses 149 pacientes submetidos a apendicectomia
durante o ano de 2002 tiveram o apêndice visualizado em ultra-sonografia
pré-operatória e diagnóstico confirmado por exame histológico. Os
pacientes foram divididos em dois grupos (inicial e avançado) de acordo
com a medida do diâmetro transverso máximo do apêndice. Para análise
de dados estatísticos foram utilizadas informações demográficas (sexo
e idade) e sinais diretos e indiretos de apendicite aguda. Resultados:
Os casos de apendicite aguda se concentraram entre a 2ª e 3ª décadas
de vida, com média de 18,3 anos para o grupo inicial e 26,4 anos para o
grupo avançado, não havendo diferença estatística significativa entre
os sexos. O grupo avançado apresentou 4,5% de falsos-positivos,
enquanto o grupo inicial obteve 23,1%. Dentre os sinais diretos destaca-
se a perda da compressibilidade do apêndice encontrada em mais da
metade dos casos e com relação aos sinais indiretos a
hiperecogenicidade dos tecidos periapendiculares foi observada em
até 75% dos pacientes em ambos os grupos. Conclusão: Houve diferença
estatística significativa de casos falsos-positivos que se concentraram
com maior freqüência no grupo inicial em relação ao grupo avançado,
propondo que se realize um acompanhamento ultra-sonográfico
evolutivo nestes.
Descritores: Apendicite/diagnóstico; Apendicite/radiografia;
Apendicite/ultra-sonografia
Study carried out at Hospital Israelita Albert Einstein – HIAE – São Paulo (SP), Brazil.
1Graduate Student, Hospital Israelita Albert Einstein - HIAE, São Paulo (SP), Brazil.
2Graduate Student in Ultrasonography, Hospital Israelita Albert Einstein – HIAE, São Paulo (SP), Brazil.
3Collaborating Physician, Department of Ultrasonography, Hospital Israelita Albert Einstein - HIAE, São Paulo (SP), Brazil.
4Physican Specialized in Ultrasonography and Interventionist at HIAE, Master´s degree, Assisting Pphysician at the Instituto de Radiologia, Faculdade de Medicina - Universidade de São Paulo – INRAD
- FMUSP; Hospital Israelita Albert Einstein – HIAE, Faculdade de Medicina - Universidade de São Paulo - FMUSP, São Paulo (SP), Brazil.
5Physician, Radiologist and Interventionist, Hospital Israelita Albert Einstein - HIAE, São Paulo (SP), Brazil.
6Radiologist, Hospital Israelita Albert Einstein - HIAE, São Paulo (SP), Brazil.
7Radiologist, Hospital Israelita Albert Einstein - HIAE, São Paulo (SP), Brazil.
8PhD, Assisting Physician at the Instituto de Radiologia, Faculdade de Medicina, Universidade de São Paulo – INRAD – FMUSP, Hospital Israelita Albert Einstein – HIAE, Universidade de São Paulo -
USP, São Paulo (SP), Brazil.
9Radiologist, Hospital Israelita Albert Einstein - HIAE; Faculdade de Medicina da Universidade de São Paulo - FMUSP, São Paulo (SP), Brazil.
Corresponding author: Luciano Augusto Botter - R. Arthur de Azevedo, 142 - apto. 64 - Pinheiros - CEP 05404-012 - São Paulo (SP), Brazil - Tel.: (11) 3891-2197 - e-mail: la.botter@uol.com.br
Received on May 6, 2005 – Accepted on July 9, 2005
einstein. 2005; 3(3):185-189
186 Botter LA, Oliveira GR, Farias JL, Mauramo A , Garcia RG, Queiros MRG, Silva MRC, Neto MJF, Funari MBG
INTRODUCTION
The vermiform appendix is a long finger-shaped
projection of the cecum. It is approximately 10-cm long
and originates from the posteromedial wall of the
cecum, roughly 3.0 cm below the ileocecal valve.
Although its basis is fixed in this projection, the
appendiceal body has variable location in the abdominal
cavity and could be retrocecal, subcecal, retroileal, pre-
ileal or pelvic(1).
The inflammation of the appendix - acute
appendicitis - is rare at extremes ages and its highest
incidence is in the second decade of life(1-5). In most
cases, the etiopathogenesis is luminal obstruction due
to fecaliths, lymphoid hyperplasia, foreign bodies,
parasites and primary and secondary tumors. In a
minority of patients, the symptoms of appendicitis solve
spontaneously, at an early stage of the disease, usually
24-48 hours after the onset of pain; probably due to
relief of an obstruction (expelled fecalith, regression
of lymphoid hyperplasia).
Acute appendicitis is the most common cause of
surgical acute abdomen(1-3). An early diagnosis is
essential to minimize morbidity. Successful surgical
treatment implies in reducing negative laparotomies,
with less cases of perforation determining the timely
moment for the procedure(1).
In this scenario, investigation by imaging studies
(particularly ultrasonography and computed
tomography) contributes to the clinical history/physical
examination and laboratory data to optimize
management.
OBJECTIVE
To evaluate the role of sonography in diagnosis of acute
appendicitis, with an emphasis on cases in which the
appendix had no marked dilation, measuring from 6.0
to 7.9 mm.
METHODS
A retrospective study of 240 patients submitted to
appendicectomy at the Hospital Israelita Albert
Einstein (HIAE), in 2002, was carried out to evaluate
sensibility of ultrasonography in diagnosis of acute
appendicitis. All cases with diagnosis confirmed by
pathological examination were included. Patients not
submitted to preoperative ultrasonography at this
hospital were excluded.
The sonographic findings before surgery were
collected through a standardized questionnaire
including demographic data (sex, age); direct signs
(thickening of appendix, that is, maximum external
diameter > 6.0 mm; non-compressibility of the
appendix; hypoechogenicity of the appendiceal wall
and presence of appendicolith) and indirect signs of
appendicitis (hyperechogenicity of periappendiceal
tissues; free periappendiceal fluid; hypervascularization
at color Doppler/power Doppler; lymphadenomegly;
collections and thickening of the ileum/cecum), as well
as pathological diagnosis.
For analysis, 149 patients whose appendix was
visualized at the preoperative sonography, including
measure of the maximum anteroposterior external
diameter, were selected. Patients were distributed into
two groups: appendix suggesting initial appendicitis,
characterized by slight/moderate thickening (6.0 to 7.9
mm); and appendix suggesting appendicitis at a more
advanced stage, characterized by greater thickening
(= 8.0 mm). We compared ultrasonographic sensibility
in the two groups, as well as frequency of direct and
indirect signs. The statistical significance level was
p < 0.05.
RESULTS
Demographic data
The mean age of each ultrasonographic group (initial
and advanced) was 18.3 and 26.4 years, respectively.
The youngest patient was 5 years old and the oldest,
79 years. There was no statistically significant difference
between sexes.
Direct signs
The direct sonographic signs of acute appendicitis
taken into account were thickening of appendix, that
is, maximum external diameter > 6.0 mm; non-
compressibility of the appendix; hypoechogenicity of
the appendiceal wall and presence of appendicolith.
All patients included in the study had their appendix
visualized and the maximum external diameter could
be measured. Based on this dimension, the patients
were divided as “suspected initial” phase of
appendicitis (thickness of 6.0 to 7.9 mm); and
“suspected advanced” phase. Table 1 shows sensibility
of ultrasonography for the initial and advanced groups
after correlation with postoperative pathological
findings. Out of 110 cases with a diameter classified as
advanced appendicitis, 95.5% were confirmed by
pathological examination. In this group, 4.5% of the
results were false-positive. In 39 cases in which the
appendiceal diameter indicated initial appendicitis,
only 76.9% were confirmed, and there were 23.1% of
false-positive results. This difference was statistically
significant (p < 0.005).
einstein. 2005; 3(3):185-189
187Ultrasonography in the diagnosis of acute appendicitis
Table 1. Sensibility of ultrasonography for initial and advanced groups
APPENDICITIS INITIAL ADVANCED TOTAL
YES 76.9% (30 cases) 95.5% (105 cases) 135 cases
NO 23.1% (09 cases) 4.5% (05 cases) 14 cases
TOTAL 39 cases 110 cases 149 cases
As to false-positive examinations, the mean maximum
external diameter in the initial group was 6.48 mm, median
of 6.30 mm, ranging from 6.0 to 7.0 mm. In the advanced
group, the mean was 8.6 mm, median of 8,0 mm, ranging
between 8.0 a 10.0 mm (figure 1).
Doppler/power Doppler; lymphadenomegly; collections
and thickening of the ileum/cecum.
Hyperechogenicity of periappendiceal tissues was
the most often observed sign in the advanced group
(75.2%, 79 patients), in whom the appendix had a
slight/moderate thickening. In the initial group this
sign was frequent (56.7%, 17 patients). There was no
statistically significant difference between the groups.
The high frequency of this indirect sign confirms its
relevance in diagnosis of acute appendicitis (figure 3).
Figure 1. Longitudinal section of a thickened appendix measuring up to 8.4 mm,
not compressible. The postoperative diagnosis was ulcerative appendicitis
Non-compressibility was the direct sign mostly
observed in ultrasonography after appendiceal
thickening, both in the initial (19 patients, 63.3%) and
advanced (54 patients, 54%) groups. There was no
statistically significant difference between the groups.
Together with free periappendiceal fluid and
hyperechogenicity of periappendiceal tissues, they
comprise the main sonographic findings associated with
thickening of appendix in our study.
Hypoechogenicity of the appendiceal wall was
observed in 7 patients (23.3%) in the initial group and
in 22 patients (20.9%) of the advanced group. The
difference was not statistically significant.
The presence of appendicolith was detected in only
4 patients (13.3%) of the initial group and in 27 patients
(25.7%) of the advanced group. Despite the higher
association with advanced cases, there was no
statistically significant difference (figure 2).
Indirect signs
The indirect signs included in the study were
hyperechogenicity of periappendiceal tissues; free
periappendiceal fluid; hypervascularization at color
Figure 2. A 9-year-old male patient. Thickened and not compressible
appendix, anteroposterior external diameter of up to 11 mm. This longitudinal
section shows an appendicolith of 4.5 mm in its interior. Ulcerative
suppurative appendicitis
Figure 3. Cross section of appendix of another patient with acute appendicitis
demonstrating hyperechogenicity surrounding the organ
einstein. 2005; 3(3):185-189
188 Botter LA, Oliveira GR, Farias JL, Mauramo A , Garcia RG, Queiros MRG, Silva MRC, Neto MJF, Funari MBG
The presence of free periappendiceal fluid, another
ultrasonographic sign often observed in our study, was
found in 11 patients (36.7%) of the initial group and
in 55 patients (52.4%) of the advanced group. The
difference was not statistically significant (figure 4).
The statistical data on incidence of direct and
indirect signs of acute appendicitis in both groups are
displayed in table 2.
Figure 4. Free periappendiceal fluid and hyperechogenicity of adjacent fat tissues
Figure 5. Color and power Doppler demonstrate marked circumferential
vascularization. Ulcerative suppurative appendicitis
Table 2. Frequency of direct and indirect signs according to initial and advanced group
SIGNS INITIAL ADVANCED P
Non-compressibility 63.3%(19) 51.4%(54) 0.3013
Hypoechogenicity of 23.3%(07) 20.9%(22) 0.8032
appendiceal wall
Appendicolith 13.3%(04) 25.7%(27) 0.2189
Free fluid 36.7%(11) 52.4%(55) 0.1504
Hypervascularization at 26.7%(08) 33.3%(35) 0.6572
Doppler
Hyperechogenicity of 56.7%(17) 75.2%(79) 0.0667
periappendiceal tissues
Lymphadenomegly 33.3%(10) 16.2%(16) 0.0361
Collections 0 3.8%(04) 0
Ileal/cecum thickening 10.0%(03) 3.8%(04) 0.1834
DISCUSSION
Considering the high number of patients with clinical
suspicion of acute appendicitis in emergency services,
the imaging methods play an important role as adjuvant
in making diagnosis, in order to minimize unnecessary
appendicectomies and not increase the risk of eventual
progression to perforation due to delayed surgical
procedure(1-2).
There were no statistically significant differences
regarding age and sex as compared with the medical
literature. The highest frequencies are concentrated
in the second and third decades of life(3-6).
The distribution of patients in initial and advanced
groups was based on the maximum external
anteroposterior diameter of the appendix observed in
the preoperative sonography. In fact, a 6.0-mm
diameter is a sign of thickened appendix, but recent
reports in the literature have suggested that such cutoff
point may increase the number of false-positive
appendicectomies(3). In the present study, the advanced
group had a reduced number of false-positive results,
whereas the initial group had statistical significant
difference with higher rates. The variation in
appendiceal diameter in the initial group was in
agreement with recent reports in the literature.(5-11)
These data indicate a follow-up of patients should be
made before referring directly to surgery.
As to frequency of other ultrasonographic direct and
indirect signs, a comparative analysis was performed with
the true-positive groups. Among the direct signs, non-
compressibility of the appendix stood out and was
observed in more than half cases of appendicitis in both
groups. The presence of appendicoliths was more
frequent in advanced than initial cases, likewise in the
literature(1-2). As to direct signs, hyperechogenicity of
periappendiceal tissues was observed in most cases in both
Circumferential hypervascularization of the
appendix at color Doppler or power Doppler
demonstrates the presence of an inflammatory/
reactional process in the whole organ. This sign was
detected in 8 patients (26.7%) of the initial group and
in 35 patients (33.3%) of the advanced group. There
was no statistically significant difference between the
groups (figure 5).
The presence of enlarged lymph nodes was found
in 10 patients (33.3%) of the initial group and in 16
patients (15.2%) of the advanced group. The difference
was statistically significant.
The presence of collections or ileocecal thickening
were not very frequent and did not allow further
considerations about its importance in the diagnosis
of acute appendicitis.
einstein. 2005; 3(3):185-189
189Ultrasonography in the diagnosis of acute appendicitis
groups. Moreover, considering the inflammatory reactions
adjacent to the appendix, the presence of circumferential
hypervascularization at color Doppler and power Doppler
as well as free periappendiceal fluid stood out.
CONCLUSION
There was statistically significant differences between
the false-positive results in the initial and advanced
groups, which were defined by the maximum
anteroposterior diameter of the appendix.
The maximum appendiceal diameter of the appendix
varied from 6.0 to 7.0 mm in the false-positive cases of
the initial group. Based on our data and according to
recent reports in the literature, a sonographic follow-
up of these patients should be performed.
Other direct and indirect signs of acute appendicitis
should also be investigated, such as hyperechogenicity
of periappendiceal tissues, non-compressibility, free
periappendiceal fluid and circumferential
hypervascularization at Doppler, besides fecoliths. The
influence of these signs in reducing false-positive results
in the group of patients with discreet appendiceal
thickening demands further prospective studies, for
active search of these signs in all patients.
REFERENCES
1. Zorzetto, AA, Urban LABD, Liu CB, Cruz OR, Vitola MLM, Awamura Y et al. O uso da ultra-
sonografia no diagnóstico e evolução da apendicite aguda. Radiol Bras. 2003;36(2):71-5.
2. Birnbaum BA, Wilson SR. Appendicitis at the millennium. Radiology.
2000;215(2):337-48.Review.
3. Puig S, Hörmann M, Rebhandl W, Felder-Puig R, Prokop M, Paya K. US as a
primary diagnostic tool in relation to negative appendectomy: Six years
experience. Radiology. 2003;226(1):101-4.
4. Simonovsky V. Normal appendix: Is there any significant difference in the
maximal mural thickness at US between pediatric and adult populations?
Radiology. 2002;224(2):333-7.
5. Rettenbacher T, Hollerweger A, Macheiner P, Rettenbacher L, Tomaselli F,
Schneider B et al. Diameter of the vermiform appendix as a sign of acute
appendicitis: evaluation al US. Radiology. 2001;218(3):757-62.
6. Cobben LPJ, de Van Otterloo AM, Puylaert JB. Spontaneously resolving appendicitis:
frequency and natural history in 60 patients. Radiology. 2000;215(2):349-52.
7. Rettenbacher T, Hollerweger A, Macheiner P, Gritzmanm N, Daniaux M,
Schwamberger H et al. Ovoid shape of the vermiform appendix: a criterion to
exclude acute appendicitis – evaluation with US. Radiology. 2003;226(1):95-100.
8. Kaiser S, Frenckner B, Jorulf HK. Suspected appendicitis in children: US and
CT – a prospective randomized study. Radiology. 2002;223(3):633-8.
9. Ndoye JM, Ndiaye A, Ndiaye A, Dia A, Fall B, Diop M et al. [Cadaveric topography and
morphometry of the vermiform appendix]. Morphologie. 2005;89(285):59-63. French.
10. Poortman P, Lohle PN, Schoemaker CM, Oostvogel HJ, Teepen HJ, Zwinderman
KA et al. Comparison of CT and sonography in the diagnosis of acute appendicitis:
a blinded prospective study. Am J Roentgenol. 2003;181(5):1355-9.
11 . Chan I, Bicknell SG, Graham M. Utility and diagnostic accuracy of sonography in detecting
appendicitis in a community hospital. Am J Roentgenol. 2005:184(6):1809-12.
