What is the average appendix size

When interpreting a cross-sectional imaging study performed to evaluate for acute appendicitis, the first step is to identify the appendix. A dilated, thick-walled appendix with periappendiceal fat stranding is diagnostic of acute appendicitis Figs.

Axial contrast enhanced CT demonstrates dilated thick-walled appendix 11 mm diameter solid arrow with periappendiceal inflammatory changes dashed arrow Fig. Axial contrast enhanced CT demonstrates dilated thick-walled blind ended appendix 12 mm diameter solid arrow with periappendiceal inflammatory changes dashed arrow Fig. Axial T2-weighted MR images without a and with b fat saturation, demonstrate thick-walled appendix solid arrow with periappendiceal inflammatory changes dashed arrow.

Note that periappendiceal inflammation is much more apparent on the T2 with fat saturation image b Appendiceal wall thickening is an extremely helpful finding for making the diagnosis of acute appendicitis [ 31 , 32 ] and may be the only abnormal finding in a patient with early acute appendicitis. Appendiceal diameter also can be a helpful parameter, but should not be evaluated in isolation as a finding used to rule in or rule out acute appendicitis.

It is important to note that the 6 mm cutoff is based on ultrasound literature in which appendices were evaluated with graded compression [ 21 ]. In fact, any strict diameter cutoff should be used with caution given the variability in normal appendiceal diameter noted above. Periappendiceal inflammation appears as increased attenuation within periappendiceal fat at CT Figs. Periappendiceal fat stranding is highly suggestive of acute appendicitis if the appendix is enlarged [ 34 ]. Therefore, the appendix and surrounding structures must be evaluated carefully in the setting of periappendiceal fat stranding to accurately determine the etiology of fat stranding.

Therefore, correlation should always be made with patient symptoms before a patient is diagnosed with acute appendicitis. Axial contrast-enhanced CT images demonstrate marked cecal wall thickening with surrounding inflammation a, arrow as well as wall thickening of the appendix with surrounding inflammation b, arrow.

Terminal ileum c, arrow is also thick walled with upstream loops of dilated small bowel. If the appendix is not visualized, there are no inflammatory changes in the right lower quadrant, and there is sufficient intraperitoneal fat in the right lower quadrant to assess for inflammatory changes, acute appendicitis can safely be excluded [ 23 ].

Once a determination of acute appendicitis has been made, the next step is to evaluate for evidence of perforation. Patients with perforated appendicitis and periappendiceal fluid collections may undergo CT-guided drainage of the fluid collections.

Findings indicating appendiceal perforation include periappendiceal fluid collections, extraluminal air, and an extraluminal appendicolith Fig.

The average length of the appendix is cm range cm. Normal appendix does not exceed 6 mm in maximal outer diameter MOD and should be compressible. Ultrasonography of normal and abnormal appendix in children. World J Radiol. Promoted articles advertising. How to use cases.

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Case creation learning pathway. By System:. Patient Cases. Contact Us. A 6-mm short-axis thickness is used as the upper limit of normal. This extrapolation of US findings of a normal appendiceal thickness is based on the size of a compressed and collapsed appendix without taking the luminal content into consideration.

CT criteria for luminal content are based in large part on findings on barium contrast studies [4]. The aims of our study were 1 to evaluate the frequency of visualization of the normal appendix, 2 to describe the appearance of the normal appendix maximal outer diameter, wall thickness, length, intraluminal content, location of the base and tip , 3 to assess whether BMI or gender are related to visualization of the appendix and, 4 to assess whether age, gender, and body length are related to appendiceal length.

The study was approved by the ethical board. Written informed consent was obtained from all patients. The study was conducted according to the Declaration of Helsinki. Patient records and information was anonymized. A retrospective analysis of abdominal CT scans in consecutive patients undergoing CT of the abdomen was done. There were various indications, however patients with pain in the right lower quadrant or a clinical suspicion of appendicitis were excluded.

Our study group consisted of patients 95 men, 91 women; age range, 27—88 years; mean age, Of these patients, two were excluded: one because of the presence of metallic artifact from a hip prosthesis, and one because of the presence of motion artifact. CT scans were obtained with a slice multidetector CT Sensation 16, Siemens; Erlangen, Germany with 2 mm collimation and reconstructions every 2 mm.

Scanning was performed from the dome of the diaphragm to the pubic symphysis. Scans were obtained during the portal venous phase. The reader was blinded to the patients' surgical history.

The coronal and sagittal reformats were reconstructed with sections of 2-mm thickness at 2-mm intervals. The appendix was interpreted as either visualized or non-visualized. In the Vessel Extraction mode Seed Points were placed in the center of the appendix every other axial slice, thus every other mm.

Afterwards, by clicking on Manual Track, the path of the appendix was generated. The appendix was visualized along its complete length and as a curved structure, in the top left side viewport. In the top right side viewport, the appendix was seen as a linear structure.

In the top left side viewport, the reader looked for the image truly perpendicular to the axis of the appendix, which corresponded to the largest maximal outer diameter as seen in the left bottom side viewport. The maximal outer diameter of the appendix was measured in the bottom left side viewport Figure 1.

We did not measure the maximal outer diameter in the most proximal and distal part of the appendix. Wall thickness of the appendix was measured in the two opposite walls on an axial image in the same viewport Figure 2. This was also done in the left bottom side viewport, in a plane truly perpendicular to the axis of the appendix. All measurements were done to the nearest 0. In the top right side viewport, the total length of the appendix was measured.

In the top left side viewport the appendix was visualized along its complete length. Here the reader looked for the image truly perpendicular to the axis of the appendix, which corresponded to the maximal outer diameter as seen in the left bottom side viewport.

The maximal outer diameter of the appendix was measured in the bottom left side viewport. Here the reader looked for the image truly perpendicular to the axis of the appendix, which corresponded to the wall thickness of the appendix.

The wall thickness was measured in the two opposite walls on an axial image in the bottom left side viewport. We calculated the mean and range of the average appendiceal wall thickness, of the length of the appendix, and of the maximum appendiceal diameter. The density of the content of the appendix was measured on axial images. The location of the tip of the appendix was described as paracolic, adjacent and along the ascending colon; retrocolic, retrocaecal, behind the colon or caecum; pelvic, extending to the pelvis; midline, or extending to the midline.

The location of the base of the appendix was defined as superior or inferior; anterior or posterior; and medial or lateral with respect to the ileocaecal valve.

Before the examination, every patient was questioned about body length and weight, and history of appendectomy. These data were collected by investigators not involved in the image review process. Body mass index was calculated from the data available in the questionnaire. We also determined mean and range of the body mass index.

Sensitivity, specificity, negative predictive value, positive predictive value, and accuracy for visualisation of the appendix were determined.

The standard of reference for presence of the appendix was obtained by means of clinical history as recorded in the questionnaire. With the same test we also determined correlation between age and appendiceal length, as well as correlation between body length and appendiceal length.

We also evaluated the potential effect of retrocaecal or retrocolic location of the tip of the appendix on the location of the base. The prevalence of appendectomy in this cohort was The mean maximal diameter was 8.

The reviewer was unable to measure the length of the appendix in one patient, because the base could not be identified. The mean length of the normal appendix was The reviewer was unable to measure appendiceal wall thickness in eight patients, because the density of the lumen was the same as the density of the wall. The mean total thickness of the normal appendix was 2. The appendiceal tip was retrocolic or retrocaecal in 18 The reviewer was unable to localize one appendiceal base.

Thus we examined We compared the location of the appendiceal base of the retrocaecal and retrocolic tips with the location of the bases of the other tips pelvic, paracolic and, midline. The bases of the retrocaecal tips were located inferior in The bases of the retrocolic tips were located inferior in The locations of the bases of the other appendiceal tips were inferior in The normal appendices contained air and low-density material in The mean BMI of our study population was There was no statistically significant correlation between BMI and visualisation of the normal appendix P value 0.

The mean appendiceal length was Yet, rectal contrast requires catheterization. This procedure may be uncomfortable for patients, and time consuming for radiology technicians. Rectal contrast may also have a risk of appendiceal perforation [41].

Rectal contrast administration is contraindicated in neutropenic patients,those with peritoneal signs, and evidence of perforation [7]. Oral contrast often is tolerated poorly and may delay treatment by several hours [43] , [44] , as it takes 45 minutes to 2 hours for the contrast material to reach the caecum [40] , [41] , [45]. Oral contrast is poorly tolerated by patients with nausea, resulting in further delay. An important advantage of IV contrast is that it allows a complete assessment of other abdominal pathologic conditions [46].

In this study, the mean maximal diameter was 8.