Appendiceal CT Research Articles

Clinical course in children with equivocal appendicitis on computed tomography: a retrospective cohort study.

Appendectomy is one of the most common surgeries in children. Although various radiological examinations are performed, they do not always reveal a definitive diagnosis of appendicitis. This study aimed to investigate the clinical course of equivocal appendicitis, identify the factors associated with appendectomy, and suggest appropriate management for these patients. Patients younger than 19 years who visited Seoul National University Bundang Hospital with a differential diagnosis of appendicitis from January 2013 to December 2017 were included. All participants conducted 'appendiceal CT' with a scoring scale of 1-5. The higher the score, the higher the likelihood of a radiologic diagnosis of appendicitis. We defined the appendicitis CT score of 2-4 as equivocal appendicitis (n = 143). Medical records were reviewed retrospectively for demographics, further examination as abdominal ultrasonography, and appendectomy status (yes or no). The mean follow-up period was 15.6 ± 71 days. Equivocal appendicitis accounted for 16.7%. Additional ultrasonography test was performed in 24.5% (35 of 143). In total, 34 patients (23.8%) underwent appendectomy. Among the patients with appendiceal CT scores 2, 3, and 4, 4.9%, 50.0%, and 87.5% underwent appendectomy, respectively. Higher WBC count, higher appendicitis CT score, and readmission were significantly associated with appendectomy in patients with equivocal appendicitis. Higher appendicitis CT score and WBC level were positively associated with appendectomy. Careful observation can be a treatment option in appendicitis CT score 2 or 3 groups. Appendectomy is the first-line treatment for patients with appendicitis score 4. Additional ultrasonography test is advisable to determine treatment modality for equivocal appendicitis.

A Comparative Study of Unenhanced Focused Appendiceal CT and Sonography for the Diagnosis of Acute Appendicitis

A Comparative Study of Unenhanced Focused Appendiceal CT and Sonography for the Diagnosis of Acute Appendicitis

Focused CT for the evaluation of suspected appendicitis.

To determine the diagnostic accuracy of focused appendiceal CT as a feasible alternative to the standard CT of the abdomen and pelvis (CT-AP) in patients with suspected acute appendicitis. Retrospective review of 200 adults with suspected acute appendicitis between January and October 2016 were included in this study. Each patient underwent CT-AP with oral and intravenous (IV) contrast. A subset of axial images starting at the top of L4 vertebral body to the roof of the acetabula were obtained from each study which served as the focused appendiceal CT. After review of the focused CTs, the non-focused CT-AP scans were reviewed, each patient acting as their own control. Images were assessed for ability to identify the appendix, assess for appendicitis, or identify alternative diagnoses that could account for the presenting symptoms. Of 200 cases, the appendix was visualized in the focused CT in 191 patients. In nine studies, the appendix was not visualized in focused or standard CT-AP. Using focused CT, 42 cases were positive for acute appendicitis. This result was identical when reviewing standard CT-AP. Alternative diagnoses were present in 38 patients. Using focused CT, 14 of these were not fully covered but the readers were able to make the diagnoses confidently on the focused CTs. Only one patient had acute non-appendiceal pathology mostly outside of the field of view. Focused appendiceal CT with IV and oral contrast in the setting of clinically suspected appendicitis is a suitable alternative to conventional CT-AP.

Can We Perform CT of the Appendix with Less Than 1 mSv? A De-escalating Dose-simulation Study.

To systematically explore the lowest reasonably achievable radiation dose for appendiceal CT using an iterative reconstruction (IR) in young adults. We prospectively included 30 patients who underwent 2.0-mSv CT for suspected appendicitis. From the helical projection data, 1.5-, 1.0- and 0.5-mSv CTs were generated using a low-dose simulation tool and the knowledge-based IR. We performed step-wise non-inferiority tests sequentially comparing 2.0-mSv CT with each of 1.5-, 1.0- and 0.5-mSv CT, with a predetermined non-inferiority margin of 0.06. The primary end point was the pooled area under the receiver-operating-characteristic curve (AUC) for three abdominal and three non-abdominal radiologists. For the abdominal radiologists, the non-inferiorities of 1.5-, 1.0- and 0.5-mSv CT to 2.0-mSv CT were sequentially accepted [pooled AUC difference: 2.0 vs. 0.5 mSv, 0.017 (95% CI: -0.016, 0.050)]. For the non-abdominal radiologists, the non-inferiorities of 1.5- and 1.0-mSv CT were accepted; however, the non-inferiority of 0.5-mSv CT could not be proved [pooled AUC difference: 2.0 vs. 1.0 mSv, -0.017 (-0.070, 0.035) and 2.0 vs. 0.5 mSv, 0.045 (-0.071, 0.161)]. The 1.0-mSv appendiceal CT was non-inferior to 2.0-mSv CT in terms of diagnostic performance for both abdominal and non-abdominal radiologists; 0.5-mSv appendiceal CT was non-inferior only for abdominal radiologists. • For both abdominal and non-abdominal radiologists, 1.0-mSv appendiceal CT could be feasible. • The 0.5-mSv CT was non-inferior to 2.0-mSv CT only for expert abdominal radiologists. • Reader experience is an important factor affecting diagnostic impairment by low-dose CT.

Low-dose CT for the diagnosis of appendicitis in adolescents and young adults (LOCAT): a pragmatic, multicentre, randomised controlled non-inferiority trial

CT radiation is arguably carcinogenic. Results from single-centre studies, mostly retrospective, have advocated lowering the CT radiation dose for the diagnosis of appendicitis. However, adoption of low-dose CT has been slow. We aimed to assess the effectiveness of low-dose CT compared with standard-dose CT in the diagnosis of appendicitis in adolescents and young adults. We did this pragmatic, multicentre, randomised controlled non-inferiority trial at 20 South Korean teaching hospitals with little experience with low-dose CT. Patients aged 15-44 years with suspected appendicitis were randomly assigned (1:1), via computer-generated random assignments (permuted block sizes of two, four, six, and eight) concealed in sequentially numbered envelopes, to receive low-dose CT (2 mSv) or standard-dose CT (≤8 mSv). Randomisation was stratified by site. Group allocation was concealed from patients, outcome assessors, and adverse event adjudicators; care providers, site pathologists, and data collectors were aware of allocation. The primary endpoint was the negative (unnecessary) appendectomy rate among all appendectomies, with a non-interiority margin of 4·5% for low-dose versus standard-dose CT. Primary analysis was by modified intention to treat, which included all patients who received an appendectomy in the group to which they were assigned. This trial is registered with ClinicalTrials.gov, number NCT01925014. Between Dec 4, 2013, and Aug 18, 2016, we assigned 1535 patients to the low-dose CT group and 1539 patients to the standard-dose CT group. 22 (3·9%) of 559 patients had a negative appendectomy in the low-dose group versus 16 (2·7%) of 601 patients in the standard-dose group (difference 1·3%, 95% CI -0·8 to 3·3; p=0·0022 for the non-inferiority test). We recorded 43 adverse events in 43 (2·8%) of 1535 patients in the low-dose group and 41 adverse events in 40 (2·6%) of 1539 patients in the standard-dose group. One life-threatening adverse event of anaphylaxis caused by an iodinated contrast material occurred in the low-dose group. Radiation dose of appendiceal CT for adolescents and young adults can be reduced to 2 mSv without impairing clinical outcomes. In view of the vast number of appendiceal CT examinations done worldwide, use of low-dose CT could prevent a sizeable number of radiation-associated cancers in the future. Korea Health Industry Development Institute, Seoul National University Bundang Hospital, Dasol Life Science, and Bracco Imaging Korea.

Acute appendicitis: implementing low-dose CT in clinical practice

Although acute appendicitis is the most common cause of abdominal pain in emergency departments, its diagnosis remains challenging. Diagnosis has previously been made on the basis of patient history, clinical surgical diagnosis, and laboratory findings. Several scoring systems based on these clinical findings have been created to aid diagnosis, 1 Alvarado A A practical score for the early diagnosis of acute appendicitis. Ann Emerg Med. 1986; 15: 557-564 Summary Full Text PDF PubMed Scopus (968) Google Scholar , 2 Andersson M Andersson RE The appendicitis inflammatory response score: a tool for the diagnosis of acute appendicitis that outperforms the Alvarado score. World J Surg. 2008; 32: 1843-1849 Crossref PubMed Scopus (219) Google Scholar but the accuracy of clinical diagnosis without preoperative imaging is about 76–80%. 3 Korner H Sondenaa K Soreide JA et al. Incidence of acute nonperforated and perforated appendicitis: age-specific and sex-specific analysis. World J Surg. 1997; 21: 313-317 Crossref PubMed Scopus (270) Google Scholar Because acute appendicitis has been thought to always progress to perforation requiring emergency appendectomy, high negative (unnecessary) appendectomy rates, even up to 40% in some patient populations, have been accepted as good surgical practice. For the past two decades, use of dedicated imaging of the acute abdomen generally and also in patients with acute appendicitis has led to improved diagnostic accuracy. The increased use of preoperative CT imaging has been thoroughly assessed by investigating its effect on the numbers of negative appendectomies. After implementation of mandatory imaging guidelines for suspected appendicitis in the Netherlands, the negative appendectomy rate dropped significantly, from 23% to 6% (p<0·001), resulting in an average cost-per-patient decrease of €594. 4 Lahaye MJ Lambregts DM Mutsaers E et al. Mandatory imaging cuts costs and reduces the rate of unnecessary surgeries in the diagnostic work-up of patients suspected of having appendicitis. Eur Radiol. 2015; 25: 1464-1470 Crossref PubMed Scopus (44) Google Scholar Low-dose CT for the diagnosis of appendicitis in adolescents and young adults (LOCAT): a pragmatic, multicentre, randomised controlled non-inferiority trialRadiation dose of appendiceal CT for adolescents and young adults can be reduced to 2 mSv without impairing clinical outcomes. In view of the vast number of appendiceal CT examinations done worldwide, use of low-dose CT could prevent a sizeable number of radiation-associated cancers in the future. Full-Text PDF

Comparison of filtered back projection and iterative reconstruction in diagnosing appendicitis at 2-mSv CT

To compare radiologists' diagnostic performance and confidence, and subjective image quality between filtered back projection (FBP) and iterative reconstruction (IR) at 2-mSv appendiceal CT. The institutional review board approved this retrospective study and waived the requirement for informed consent. We included 107 adolescents and young adults (age, 29.8±8.5years; 64 females) undergoing 2-mSv CT for suspected appendicitis. Appendicitis was pathologically confirmed in 42 patients. Seven readers with different experience levels independently reviewed the CT images reconstructed using FBP and IR (iDose(4), Philips). They rated both the likelihood of appendicitis and subjective image quality on 5-point Likert scales. Diagnostic confidence was assessed usingthe likelihood of appendicitis, proportion of indeterminate interpretations, and 3-point normal appendix visualization score. We used receiver operating characteristic analyses, Wilcoxon's signed-rank tests, and McNemar's tests. The pooled area under the receiver operating characteristic curve (AUC) was 0.96 for both FBP and IR (95% CI for the difference, -0.02, 0.02; P=0.73). The AUC difference was not significant in any of the individual readers (P≥0.21). For the majority of the readers, the diagnostic confidence was not significantly different between the two reconstruction methods. Subjective image quality tended to be higher with IR for all readers (P≤0.70), showing significant differences for four readers (P≤0.040). When diagnosing appendicitis at 2-mSv CT in adolescents and young adults, FBP and IR were comparable in radiologists' diagnostic performance and confidence while IR exhibited higher subjective image quality than FBP.

Initial Performance of Radiologists and Radiology Residents in Interpreting Low-Dose (2-mSv) Appendiceal CT.

The objective of our study was to prospectively evaluate the initial diagnostic performance and learning curve of a community of radiologists and residents in interpreting 2-mSv appendiceal CT. We included 46 attending radiologists and 153 radiology residents from 22 hospitals who completed an online training course of 30 2-mSv CT cases. Appendicitis was confirmed in 14 cases. Most of the readers had limited (≤ 10 cases, n = 32) or no (n = 118) prior experience with low-dose appendiceal CT. The order of cases was randomized for each reader. A multireader multicase ROC analysis was performed. Generalized estimating equations were used to model the learning curves in diagnostic performance. Diagnostic performance gradually improved with years of training. The average AUC was 0.94 (95% CI, 0.90-0.98), 0.92 (0.88-0.96), 0.90 (0.85-0.96), and 0.86 (0.80-0.92) for the attending radiologists, senior residents, 2nd-year residents, and 1st-year residents, respectively. We did not observe any notable intrareader learning curves over the training course of the 30 cases except a decrease in reading time. Diagnostic accuracy and sensitivity were significantly affected by the reader training level and prior overall experience with appendiceal CT but not by the prior specific experience with low-dose appendiceal CT. The learning curve is likely prolonged and forms gradually over years by overall radiology training and clinical experience in general rather than by experience with low-dose appendiceal CT specifically.

Computed Tomography-Based Clinical Diagnostic Pathway for Acute Appendicitis: Prospective Validation

Despite our regular use of CT for suspected appendicitis, a recent study at our institution demonstrated a negative appendectomy (NA) rate similar to our rate 15 years earlier. Based on analysis of this data, a diagnostic pathway was implemented prospectively for adult patients with possible appendicitis. Rates of CT, NA, and perforation for nonpregnant patients over 14 years of age undergoing appendectomy between August 2001 and August 2002 (PRE) were compared with prospectively collected pathway data (PATH, August 2004 to August 2005). All PATH patients were evaluated by a surgeon before CT. All females underwent CT. CT was obtained in male patients with low suspicion or pain for longer than 48 hours. After negative CT, patients were discharged from the emergency department or admitted for observation. There was a substantial decrease in NA rate after implementation of the pathway (4% PATH [8 of 183] versus 16% PRE [31 of 196], p < 0.001), without a change in the rate of perforation (11% PATH [20 of 175] versus 8% PRE [13 of 165], p = 0.28) or frequency of preoperative CT (59% PATH [108 of 183] versus 60% PRE [118 of 196], p = 0.84). Frequent appendiceal CT alone does not ensure surgical diagnostic accuracy. CT need not be used in all patients to achieve very low NA rates. An evidence-based diagnostic algorithm incorporating early surgical evaluation, objective criteria for preoperative CT, deterrence of early operation after negative CT, and use of CT to facilitate safe discharge led to substantial improvements in the care of our adult population presenting with possible appendicitis.

The Status of Appendiceal CT in an Urban Medical Center 5 Years After Its Introduction: Experience With 753 Patients

The Status of Appendiceal CT in an Urban Medical Center 5 Years After Its Introduction: Experience With 753 Patients

Author’s Reply

As the diagnostic capabilities of radiology continue to expand, clinicians’ reliance on imaging studies will only increase. The evaluation of patients with suspected appendicitis is an excellent example of an area in which imaging has become indispensable [ 1 Rhea J.T. Halpern E.F. Ptak T. Lawrason J.N. Sacknoff R. Novelline R.A. The status of appendiceal CT in an urban medical center 5 years after its introduction experience with 753 patients. Am J Roentgenol. 2005; 184: 1802-1808 Crossref PubMed Scopus (87) Google Scholar ]. Given that radiology has now become a 24-hour specialty, we are faced with making an important decision about who should be rendering interpretations. Does it make logical sense to have a resident make what in essence amounts to a final decision at night but not during the day? After all, you can’t very well have a surgeon place a normal appendix back into someone’s abdomen after an attending physician comes in and renders an official reading at 8 am. On-Call Resident Preliminary Reads: Should the Process Continue?Journal of the American College of RadiologyVol. 2Issue 12PreviewI read with great interest the most recent “Residents’ Column,” in which Dr Bansal [1] described the impact of 24-hour attending physician coverage on the resident training at his institution. The majority of the residents at his institution seemed to be in favor of this new system, because it led to a decrease in on-call hours as well as a decrease in “fear and uncertainty” while on call. Full-Text PDF

The Status of Appendiceal CT in an Urban Medical Center 5 Years After Its Introduction: Experience with 753 Patients

Appendiceal CT was introduced at our hospital in 1996 and now is used in most patients. The use of appendiceal CT has generated controversy and mixed results in various investigations. Our purpose was to determine the percentage of patients for whom CT was performed, incidence of appendicitis, accuracy of CT, percentage of equivocal interpretations, and negative appendectomy rates for those patients who did and did not undergo CT. Patient records from 2001 that included clinical or CT preoperative examination were analyzed, with follow-up through 2003. Patient age and sex, clinical presentation, CT techniques, CT interpretations, operative reports, pathology reports, and patient disposition were determined. Final diagnoses were provided by pathologic criteria, patient follow-up, or patient survey. Statistical analysis included Fisher's exact test and receiver operating characteristic (ROC) curves. Of 753 patients, 663 (88%) were examined on CT for suspected appendicitis and 90 had an appendectomy without undergoing CT. The incidence of appendicitis in the patients who underwent CT was 39.2%. The sensitivity and specificity of CT were 99% and 95%, respectively; the area under the ROC curve was 0.9896; and the percentage of equivocal CT interpretations was 3.3%. The false-negative appendectomy rates were 3.0% and 5.6% for patients with and without CT, respectively (for all patients, p = 0.326; for female pediatric patients, p = 0.030). Five years ago, the negative appendectomy rate dropped from 20% to 7%, and it is now 3.0%. The incidence of appendicitis in patients who are examined on CT is stable compared with similar cohorts from prior investigations. Patients who do not undergo CT also have a low negative appendectomy rate, but this relatively small group is selected on the basis of a convincing clinical presentation. Female pediatric patients likely would have a lower negative appendectomy rate with greater use of CT.

The most useful findings for diagnosing acute appendicitis on contrast-enhanced helical CT.

To evaluate the most useful findings to look for in diagnosing acute appendicitis on contrast-enhanced helical CT. Appendiceal helical CT scans with intravenous contrast administration (abdomen, 7-mm collimation; abdominopelvic junction, 5-mm collimation) of 71 patients with surgically proven acute appendicitis and 167 patients with alternative diagnoses were reviewed retrospectively. Three radiologists analyzed the following parameters: enlarged appendix (>6 mm in diameter), appendiceal wall thickening, appendiceal wall enhancement, no identification of the appendix, appendicolith(s), appendiceal intraluminal air, intramural air, extraluminal air, periappendiceal fat stranding, extraluminal fluid, phlegmon, abscess, lymphadenopathy, segmental terminal ileal wall thickening, focal cecal apical thickening, focal colonic wall thickening, and segmental colonic wall thickening. The features that best distinguished appendicitis from alternative diagnoses were selected with stepwise logistic regression analysis. Nine CT findings distinguished acute appendicitis from alternative diagnoses (P < 0.05): enlarged appendix (R = 0.739), appendiceal wall thickening (R = 0.525), periappendiceal fat stranding (R = 0.414), appendiceal wall enhancement (R = 0.404), focal cecal apical thickening (R = 0.171), appendicolith(s) (R = 0.157), extraluminal air (R = 0.050), intramural air (R = 0.043), and phlegmon (R = 0.030). Enlarged appendix (sensitivity, 93%; specificity, 92%), appendiceal wall thickening (sensitivity, 66%; specificity, 96%), periappendiceal fat stranding (sensitivity, 87%; specificity, 74%), and appendiceal wall enhancement (sensitivity, 75%; specificity, 85%) showed the statistically most significant association with acute appendicitis. On 5-mm-section contrast-enhanced helical CT examinations, enlarged appendix, appendiceal wall thickening, periappendiceal fat stranding, and appendiceal wall enhancement were the most useful findings for diagnosing acute appendicitis.

Effect of ultrasonography and optional computed tomography on the outcome of appendectomy.

The aim of this study was to investigate the value of US and complementary CT in patients with suspected appendicitis, and to detect adverse outcomes of preoperative imaging. We retrospectively reviewed the data of 233 consecutive patients who underwent an appendectomy as an emergency procedure in our hospital, within a 2-year period. Our hospital policy is to perform diagnostic imaging in all patients with clinical suspicion of appendicitis. The US was performed in 227 patients, followed by additional unenhanced helical focused appendiceal CT in 30 patients with equivocal US results. We evaluated the negative appendectomy rate, occurrence of perforation, and our in-hospital delay. Acute appendicitis was pathologically proven in 219 patients, corresponding to a negative appendectomy rate of 6%. The US with optional CT diagnosed appendicitis with a sensitivity of 96.7%. Forty-eight appendices (21.9%) were perforated. The median overall in-hospital delay was 5 h (range 0.5-123.5 h). For the perforated appendices this was 4.5 h (range 0.5-64.5 h), for the non-perforated appendices 6.0 h (range 0.5-123.5 h). In patients with suspected acute appendicitis, US examination with the option of additional CT significantly lowers the negative appendectomy rate as compared with the clinical acumen alone, without adverse effects on the perforation rate or the in-hospital delay.

Appendiceal imaging: Which test is best?

Radiologic imaging has been clearly shown to be useful for the evaluation of patients clinically suspected of having appendicitis with CT and ultrasound being the most frequently recommended modalities. However, controversy still exists as to which modality is the technique of choice for appendiceal imaging. Our experience has led us to conclude that a standard helical abdominopelvic CT is the initial test of choice for the evaluation of the adult patient suspected of having acute appendicitis. Focused appendiceal CT with colonic contrast is then utilized as a problem solving technique for equivocal cases after this initial assessment.

Can Appendiceal CT Scanning be Utilized Effectively in Widespread General Surgical Practice?

Appendiceal CT was first reported in the radiological literature, and has only recently begun to appear in the surgical literature. Much of the enthusiasm surrounding appendiceal CT has come from several publications by relatively few authors. We report the feasibility of implementing an appendiceal CT scanning technique and our initial results. The charts (940) of all patients evaluated for possible appendicitis during a 3-month period were reviewed. A new appendiceal CT scanning technique was performed when the indication was solely to exclude appendicitis. The accuracy of this new technique was determined. Eighty-seven patients were evaluated. Twenty-nine underwent appendiceal CT scanning. The accuracy of interpretation was 85 per cent. In 58 patients who did not receive an appendiceal CT scan the accuracy of surgical decision-making was 82 per cent. These values were not statistically different. We found appendiceal CT scanning to be relatively easy to implement; and its accuracy was better than expected. Our accuracy does not match that reported in the literature by the pioneers of appendiceal CT scanning. More experience with this technique will be required to achieve consistently successful accuracy; the technique can then be utilized in surgical practice and potentially change the diagnostic approach to acute appendicitis.

Acute Appendicitis: Sensitivity, Specificity and Diagnostic Accuracy of Thin-Section Contrast-Enhanced CT Findings

Purpose: To assess the sensitivity, specificity, and diagnostic accuracy of individual contrast-enhanced helical CT findings of acute appendicitis. Materials and Methods: We retrospectively reviewed the appendiceal helical CT scans, obtained after intravenous contrast administration (abdomen; 7-mm collimation, abdominopelvic junction; 5-mm collimation), of 50 patients with surgically proven acute appendicitis and 112 with alternative diagnoses. The following parameters were analysed by three radiologists: enlarged appendix (> 6 mm in diameter), appendiceal wall thickening, appendiceal wall enhancement, no identification of the appendix, appendicolith(s), (appendiceal) intraluminal air, (appendiceal) intraluminal air extraluminal air, periappendiceal fat stranding, extraluminal fluid, phlegmon, abscess, lymphadenopathy, terminal ileal wall thickening, focal cecal apical thickening, focal colonic wall thickening, and segmental colonic wall thickening. Results: The CT findings of acute appendicitis that statistically distinguished it from alternative diagnoses were an enlarged appendix (sensitivity; 92%, specificity; 93%, diagnostic accuracy; 93%), appendiceal wall thickening (for these three parameters: 68%, 96% and 88%, respectively), periappendiceal fat stranding (90%, 79%, 82%), appendiceal wall enhancement (72%, 86%, 82%), appendicolith (16%, 100%, 74%), and focal cecal apical thickening (14%, 100%, 74%) (for each, p

Diagnosing appendicitis with CT and ultrasound using prospective patient stratification by body mass index

Purpose: To determine the accuracy of CT and ultrasonography (US) in diagnosing appendicitis in adults stratified to either modality on the basis of body mass index (BMI), a measure of body habitus. Methods: Seventy-two adults with suspected appendicitis and demonstrating atypical clinical features were prospectively stratified to either appendiceal CT or US based on BMI. Patients with BMI < 30 underwent US and with BMI ≥ 30 underwent CT. Outcomes were determined by surgery, the medical record, and clinical follow-up after 3 months. Results: Of the 72 patients enrolled, 30 (24 women and 6 men) underwent CT and 42 (35 women and 7 men) underwent US. The average BMI was 34 ± 4 among patients who had CT and 24 ± 3 among patients who had US. Of the patients who had CT scans, 4 had positive scans for appendicitis and all of these were proven at surgery to have appendicitis. The remaining 26 patients had negative CT scans for appendicitis. Twenty-two of these were subsequently proven either by surgery or clinical follow-up not to have appendicitis, while 4 were lost to follow-up. This corresponds to a sensitivity, specificity, positive predictive value, and negative predictive value of 100 %. Twelve ultrasound examinations were positive for appendicitis. Nine of these patients had appendicitis proven at surgery, 1 had a perforated Meckel's diverticulum, and 2 did not have appendicitis after clinical follow-up. Twenty-seven patients had negative ultrasound exams for appendicitis. However, 6 of these had appendicitis proven at surgery, 17 did not have appendicitis, and 4 were lost to follow-up. Three patients had ultrasound exams that were equivocal for appendicitis; of these, 1 had appendicitis and 2 did not. For US, this corresponds to a sensitivity of 60 %, specificity of 85 %, PPV of 75 %, and NPV of 74 %. Conclusion: This study suggests that CT is an accurate method of evaluating adults with suspected appendicitis who have BMI ≥ 30. Stratifying patients with BMI < 30 to US did not reproduce the results already reported in the literature.

Pediatric appendicitis in "real-time": the value of sonography in diagnosis and treatment.

To determine the accuracy of sonography in the diagnosis of clinically equivocal appendicitis, and to identify the factors leading to an inaccurate ultrasound diagnosis. The impact of sonographic findings on clinical management and outcome of children with appendicitis is examined. We performed a retrospective review of 317 children who attended the emergency department (ED) of a children's hospital for acute abdominal pain for which acute appendicitis was the main differential diagnosis. They had ultrasound because the diagnosis was uncertain clinically. The positive predictive value of ultrasound for appendicitis was 0.92, and the negative predictive value was 0.88. The sensitivity and specificity could not be determined because there were 43 patients with equivocal ultrasound results. The pitfalls hindering the accuracy of ultrasound diagnosis included a high incidence of perforated appendicitis at presentation, the retrocecal appendix, and other technical factors such as abdominal guarding, excessive bowel gas, obesity, inadequate bladder filling, and the uncooperative patient. When ultrasound findings were combined with clinical judgment in clinical management, there were only five cases of non-therapeutic laparotomy and eight cases of delayed surgery due to missed diagnosis in our cohort. Ultrasound is a useful for the evaluation of acute abdominal pain in children. However, in the setting of a pediatric hospital ED, the accuracy of ultrasound and its ability to improve early hospital triage may be reduced. Repeated clinical review is still essential and in selected cases, appendiceal CT scan may be required to guide therapeutic decision making.

Appendiceal CT in pediatric patients: relationship of visualization to amount of peritoneal fat.

This study was performed to determine the rate of visualization of the normal pediatric appendix on CT and to evaluate the relationship of the appendix to parameters such as amount of intraperitoneal fat, use of contrast material, patient age, and slice thickness. Three board-certified radiologists retrospectively reviewed 248 successive pediatric abdominal and pelvic CT examinations performed from 1995 to 1999. Each radiologist independently assessed the degree of intraperitoneal fat (minimal, moderate, or marked compared with a standard slice), appendiceal visualization (definite, unsure, not seen), cecal and terminal ileal opacification, and the outer diameter of visualized appendixes. The age and sex of the patient, collimation thickness (3-10 mm), and use of enteric or IV contrast material was also recorded. A normal appendix was identified in 120 (48.4%) of 248 examinations. The only individual variable with statistically significant correlation was the degree of intraperitoneal fat. This was determined using the Pearson chi-square test, the likelihood ratio, and logistic regression. The appendix was seen in 68.8% (n = 93) of patients with moderate or marked intraperitoneal fat versus 36.1% (n = 155) with minimal fat (p<0.001). A trend toward decreased visualization in children younger than 10 years old with minimal peritoneal fat was identified and confirmed with a 95% confidence limit. The outer diameter of the visualized appendix varied from 3 to 10 mm, with a mean value of 6 mm. Increased peritoneal fat significantly increases the rate of identification of the normal appendix in pediatric patients. Although less fat is generally seen in younger patients, there is significant overlap of appendix visualization among age groups.