CT diagnosis of acute appendicitis: imaging findings

18F-FDG uptake in the normal appendix in adults: PET/CT evaluation

OBJECTIVE

This study aimed to determine the level of ¹⁸F fluorodeoxyglucose (¹⁸F-FDG) activity in the normal adult appendix using positron emission tomography/computed tomography (PET/CT).

MATERIALS AND METHODS

We performed a retrospective review of PET/CT images using ¹⁸F-FDG in 563 consecutive asymptomatic adult patients without appendiceal pathology. We excluded 257 patients for an undetected or obscured appendix and three patients for appendicitis found on CT imaging. FDG uptake in the appendix was qualitatively and quantitatively assessed. The maximum standardized uptake value (SUV_max) was calculated for quantitative analysis with SUV_max of the normal liver for comparison. A total of 303 patients (200 males, 103 females, mean age of 66 years) were included in this study. Medical charts and histories were evaluated for patients who showed positive FDG accumulation. Pearson's correlations between appendiceal SUV_max and age, body mass index, and blood glucose levels were analyzed.

RESULTS

The mean appendiceal SUV_max was 1.14 (range 0.52-5.12) with an appendix-to-liver SUV_max ratio of 0.34 (range 0.06-1.28). Three patients qualitatively showed a positive FDG accumulation with appendiceal SUV_max greater than 3.00. There were no correlations between appendiceal SUV_max and age, body mass index, or blood glucose levels.

CONCLUSIONS

FDG in the normal adult appendix shows a low activity level and is lower compared with normal liver. However, the normal appendix can rarely show high FDG accumulation. In such cases, differentiation from appendiceal pathology solely by PET/CT images would be difficult.

Accuracy of low dose CT in the diagnosis of appendicitis in childhood and comparison with USG and standard dose CT

OBJECTIVES

Computed tomography should be performed after careful consideration due to radiation hazard, which is why interest in low dose CT has increased recently in acute appendicitis. Previous studies have been performed in adult and adolescents populations, but no studies have reported on the efficacy of using low-dose CT in children younger than 10 years.

METHODS

Patients (n=475) younger than 10 years who were examined for acute appendicitis were recruited. Subjects were divided into three groups according to the examinations performed: low-dose CT, ultrasonography, and standard-dose CT. Subjects were categorized according to age and body mass index (BMI).

RESULTS

Low-dose CT was a contributive tool in diagnosing appendicitis, and it was an adequate method, when compared with ultrasonography and standard-dose CT in terms of sensitivity (95.5% vs. 95.0% and 94.5%, p=0.794), specificity (94.9% vs. 80.0% and 98.8%, p=0.024), positive-predictive value (96.4% vs. 92.7% and 97.2%, p=0.019), and negative-predictive value (93.7% vs. 85.7% and 91.3%, p=0.890). Low-dose CT accurately diagnosed patients with a perforated appendix. Acute appendicitis was effectively diagnosed using low-dose CT in both early and middle childhood. BMI did not influence the accuracy of detecting acute appendicitis on low-dose CT.

CONCLUSION

Low-dose CT is effective and accurate for diagnosing acute appendicitis in childhood, as well as in adolescents and young adults. Additionally, low-dose CT was relatively accurate, irrespective of age or BMI, for detecting acute appendicitis. Therefore, low-dose CT is recommended for assessing children with suspected acute appendicitis.

Utility of CT after sonography for suspected appendicitis in children: integration of a clinical scoring system with a staged imaging protocol

To improve diagnosis of pediatric appendicitis, many institutions have implemented a staged imaging protocol utilizing ultrasonography (US) first and then computed tomography (CT). A substantial number of children with suspected appendicitis undergo CT after US, and the efficient and accurate diagnosis of pediatric appendicitis continues to be challenging. The objective of the study is to characterize the utility of CT following US for diagnosis of pediatric appendicitis, in conjunction with a clinical appendicitis score (AS). Imaging studies of children with suspected appendicitis who underwent CT after US in an imaging protocol were retrospectively reviewed by three radiologists in consensus. Chart review derived the AS (range 0-10) and obtained the patient diagnosis and disposition, and an AS was applied to each patient. Clinical and radiologic data were analyzed to assess the yield of CT after US. Studies of 211 children (mean age 11.3 years) were included. The positive threshold for AS was determined to be 6 out of 10. When AS and US were concordant (N = 140), the sensitivity and specificity of US were similar to CT. When AS and US were discordant (N = 71) and also when AS ≥ 6 (N = 84), subsequent CT showed superior sensitivity and specificity to US alone. In the subset where US showed neither the appendix nor inflammatory change in the right lower quadrant (126/211, 60 % of scans), when AS < 6 (N = 83), the negative predictive value (NPV) of US was 0.98. However, when AS ≥ 6 (N = 43), NPV of US was 0.58, and the positive predictive value of subsequent CT was 1. There was a significant decrease in depiction of the appendix on US with patient weight-to-age ratio of >6 (kg/year, P < 0.001) and after-hours (1700 -0730 hours) performance of US (P < 0.001). Results suggest that the appendicitis score has utility in guiding an imaging protocol and support the contention that non-visualization of the appendix on US is not intrinsically non-diagnostic. There was little benefit to additional CT when AS < 6 and US did not show the appendix or evidence of inflammation; this would have avoided CT in 140/211 (66 %) patients. CT demonstrated benefit when AS ≥ 6, suggesting that cases with AS ≥ 6 and features that limit depiction of the appendix on US may be triaged to CT.

Beyond acute appendicitis: imaging and pathologic spectrum of appendiceal pathology

While acute appendicitis is a common and important clinical problem, a variety of other disease processes can affect the appendix. Simple and perforated appendicitis, tip appendicitis, and stump appendicitis share a common clinical presentation including anorexia, right lower quadrant pain, and fever. By imaging, most cases of acute appendicitis exhibit luminal dilation, wall thickening, and periappendiceal inflammatory stranding. In tip appendicitis, these changes are isolated to the distal appendix, often with an obstructing appendicolith. Perforated appendicitis can exhibit mural discontinuity, periappendiceal abscess, and/or extraluminal appendicoliths. After appendectomy, the appendiceal remnant or "stump" can become inflamed, often necessitating repeat surgery. Inflammatory bowel disease can involve the terminal ileum, secondarily involving the appendix, or may primarily involve the appendix. Patient symptoms can be chronic in such cases, and mucosal hyperenhancement is a pronounced imaging feature. In asymptomatic patients without appendiceal inflammation, the appendix can be dilated by intraluminal material such as inspissated succus in cystic fibrosis or mucus from benign appendiceal mucocele. Finally, neoplasms such as typical appendiceal carcinoid tumor and mucinous adenocarcinoma can involve the appendix. Carcinoids are often small and incidentally discovered at pathologic examination, while malignant mucinous adenocarcinoma tends to present with advanced disease including pseudomyxoma peritonei. Cecal cancers can also obstruct the appendiceal lumen and cause acute appendicitis; an astute radiologist can recognize this prospectively and facilitate definitive resection (right hemicolectomy) at the time of surgery. Attention to mural features, cecal configuration, and periappendiceal inflammation is essential to the correct prospective diagnosis of complicated appendicitis and less common appendiceal pathologies.

Diagnostic performance of diffusion-weighted MR imaging in detecting acute appendicitis in children: comparison with conventional MRI and surgical findings

PURPOSE

To determine the value of diffusion-weighted MRI for the diagnosis of acute appendicitis in children.

MATERIALS AND METHODS

Forty-five consecutive patients with a clinical diagnosis of acute appendicitis underwent abdominal MRI; 39 were operated on for acute appendicitis. First, the diffusion-weighted imaging (DWI) alone was reviewed, followed by conventional MRI alone, and then conventional MRI and DWI were reviewed by two observers within a consensus. The surgical findings were compared with the MRI. Sensitivity, specificity, and accuracy were calculated for DWI, conventional MRI, and combined DWI and conventional MRI for the depiction of acute appendicitis.

RESULTS

A combination of DWI and conventional MRI was the most sensitive and the most accurate, with corresponding sensitivity and accuracy of 0.92 and 0.92, respectively. Using DWI alone the sensitivity and accuracy was found to be 0.78 and 0.77, respectively. Using conventional MRI alone, sensitivity of 0.81 and accuracy of 0.82 was found for the consensus of the two observers.

CONCLUSION

The use of combination of DWI and conventional MRI is a valuable technique in the diagnosis of acute appendicitis in children.

Handheld device review of abdominal CT for the evaluation of acute appendicitis

Advances in handheld computing now allow review of DICOM datasets from remote locations. As the diagnostic ability of this tool is unproven, we evaluated the ability to diagnose acute appendicitis on abdominal CT using a mobile DICOM viewer. This HIPAA compliant study was IRB-approved. Twenty-five abdominal CT studies from patients with RLQ pain were interpreted on a handheld device (iPhone) using a DICOM viewer (OsiriX mobile) by five radiologists. All patients had surgical confirmation of acute appendicitis or follow-up confirming no acute appendicitis. Studies were evaluated for the ability to find the appendix, maximum appendiceal diameter, presence of an appendicolith, periappendiceal stranding and fluid, abscess, and an assessment of the diagnosis of acute appendicitis. Results were compared to PACS workstation. Fifteen cases of acute appendicitis were correctly identified on 98% of interpretations, with no false-positives. Eight appendicoliths were correctly identified on 88% of interpretations. Three abscesses were correctly identified by all readers. Handheld device measurement of appendiceal diameter had a mean 8.6% larger than PACS measurements (p = 0.035). Evaluation for acute appendicitis on abdominal CT studies using a portable device DICOM viewer can be performed with good concordance to reads performed on PACS workstations.

Goblet cell carcinoid neoplasm of the appendix: clinical and CT features

PURPOSE

To describe the clinical and CT imaging features of goblet cell carcinoid (GCC) neoplasm of the appendix.

METHODS AND MATERIALS

A computer search of pathology and radiology records over a 19-year period at our two institutions was performed using the search string "goblet". In the patients with appendiceal GCC neoplasms who had abdominopelvic CT, imaging findings were categorized, blinded to gross and surgical description, as: "Appendicitis", "Prominent appendix without peri-appendiceal infiltration", "Mass" or "Normal appendix". The CT appearance was correlated with an accepted pathological classification of: low grade GCC, signet ring cell adenocarcinoma ex, and poorly differentiated adenocarcinoma ex GCC group.

RESULTS

Twenty-seven patients (age range, 28-80 years; mean age, 52 years; 15 female, 12 male) with pathology-proven appendiceal GCC neoplasm had CT scans that were reviewed. Patients presented with acute appendicitis (n=12), abdominal pain not typical for appendicitis (n=14) and incidental finding (n=1). CT imaging showed 9 Appendicitis, 9 Prominent appendices without peri-appendiceal infiltration, 7 Masses and 2 Normal appendices. Appendicitis (8/9) usually correlated with typical low grade GCC on pathology. In contrast, the majority of Masses and Prominent Appendices without peri-appendiceal infiltration were pathologically confirmed to be signet ring cell adenocarcinoma ex GCC. Poorly differentiated adenocarcinoma ex GCC was seen in only a small minority of patients. Hyperattenuation of the appendiceal neoplasm was seen in a majority of cases.

CONCLUSIONS

GCC neoplasm of the appendix should be considered in the differential diagnosis in patients with primary appendiceal malignancy. Our cases demonstrated close correlation between our predefined CT pattern and the pathological classification.

Unenhanced MR Imaging in adults with clinically suspected acute appendicitis

PURPOSE

The purpose of the study was to evaluate unenhanced Magnetic Resonance Imaging (MRI) for the diagnosis of appendicitis or another surgery-requiring condition in an adult population scheduled for emergency appendectomy based on a clinical diagnosis of suspected acute appendicitis.

MATERIALS AND METHODS

The prospective study included 48 consecutive patients (29 female, 19 male, 18-70 years old, mean age=37.1 years). MRI examination was designed to be comfortable and fast; no contrast was administered. The sequences were performed during quiet respiration. The MRI findings were reviewed by two radiologists and one surgeon independent of each other and compared with surgical and pathological records.

RESULTS

According to the surgical and histopathological findings 30 of 48 patients (63%) had acute appendicitis. Of the remaining 18 patients, 4 patients had no reasons for the clinical symptoms and 14 patients had other pathology. For the three reviewers the performance of MRI in the diagnosis of acute appendicitis showed the following sensitivity, specificity and accuracy ranges: 83-93%, 50-83% and 77-83%. Moderate (κ=0.51) and fair (κ=0.31) interobserver agreements in the MR diagnosis of acute appendicitis were found between the reviewers. Sensitivity, specificity and accuracy values for overall performance of MRI in detecting pelvic abnormalities were 100%, 75% (3 of 4 healthy patients were identified by MRI) and 98%, respectively.

CONCLUSION

Unenhanced fast MRI is feasible as an additional fast screening before the appendectomy. It may prevent unnecessary surgeries. The fast MRI examination can be adequately performed on an MRI unit of broad range of field strengths.

Clinical Images. An unusual case of appendicitis

Situs inversus may be identified as an incidental finding when investigating abdominal pain in the acute emergency setting. We report a case of a 46-year-old man who presented with left-sided acute appendicitis on a background of situs inversus. The clinical presentation was left lower-quadrant pain. Clinically, the diagnosis of diverticulitis was made until review of plain-film imaging raised the possibility of situs inversus, and thus appendicitis. Cross-sectional imaging studies and laparoscopy confirmed the diagnosis of acute left-sided appendicitis. He underwent laparoscopic appendectomy with an uncomplicated postoperative course.

'To have...or not to have'. Should computed tomography and ultrasonography be implemented as a routine work-up for patients with suspected acute appendicitis in a regional hospital?

INTRODUCTION

Appendicitis is a common diagnosis, but is by no means a simple one to establish. This retrospective study investigated the value of medical imaging (ultrasonography and/or computed tomography [CT]) for patients with suspected appendicitis. Negative appendicectomy rate and appendiceal perforation with or without medical imaging were used as end points for this investigation.

PATIENTS AND METHODS

This study retrospectively reviewed all patients admitted in one district general hospital with suspected acute appendicitis. The patient cohort was identified from the Unit Registry and an International Classification of Diseases-based Review of medical records. The medical records were analysed, and the outcome of patients were followed up.

RESULTS

Between 12 January 2004 to 27 May 2005, 168 patients' medical records were audited. The negative appendicitis rate was 6.7% and appendiceal perforation rate was 3.2%. Among them, only 20 in-patients (12%) had medical imaging (ultrasonography and/or CT scan) after clinical assessment for suspected acute appendicitis. Medical imaging had a 70% prediction rate for acute appendicitis, 20% false-negative rate, and 10% false-positive rate. Overall, the prediction rate for appendicitis by clinical assessment supplemented by laboratory tests and medical imaging at clinician's discretion was 93.2%.

CONCLUSIONS

Despite studies advocating routine use of medical imaging for patients with suspected acute appendicitis, this study showed that the clinical evaluation is still paramount to the management of patients with suspected acute appendicitis before considering medical imaging.

Intravenous contrast-enhanced computed tomography in the diagnosis of acute appendicitis

This study evaluated the usefulness of routine, nonfocused intravenous contrast-enhanced computed tomography (CT) in diagnosing acute appendicitis. Also evaluated was the diagnostic value of several findings that were clinically associated with acute appendicitis. Although a number of studies have shown various techniques using CT to be accurate in the diagnosis of acute appendicitis, few studies have focused on CT with using only intravenous contrast material. Computed tomography scan criteria for acute appendicitis have been established chiefly on the basis of appendiceal findings. We, on the other hand, have often observed the following associated conditions during appendectomy: ascites, paresis of the intestine, or thickening of adjacent tissues. In this study, we reviewed the intravenous contrast-enhanced CT scans of 78 patients who had been diagnosed as having acute appendicitis and had subsequently undergone surgery. We also compared the CT scans with patients' surgical and histological findings. As a way of evaluating clinical ancillary signs, we identified and analyzed individual CT findings that included abnormal appendix, calcified appendicolith, ascites, dilated intestine, and cecal wall thickening. The sensitivity, specificity, and accuracy of intravenous contrast-enhanced CT in surgical cases were found to be 91.9%, 87.5%, and 91.0%, respectively. Individual findings except for abnormal appendix were not significantly common among patients who had acute appendicitis. However, more positive findings were observed in patients who had appendicitis than in those who had normal appendixes. Intravenous contrast-enhanced CT scan is a useful technique in the diagnosis of acute appendicitis. The plurality of ancillary signs in CT scans also appears to be a helpful indicator in the diagnosis of acute appendicitis.

Why we miss the diagnosis of appendicitis on abdominal CT: evaluation of imaging features of appendicitis incorrectly diagnosed on CT

OBJECTIVE

Our purpose was to retrospectively evaluate the cases of patients with surgically proven appendicitis that was misdiagnosed on abdominal CT to determine the causes of the missed diagnosis.

CONCLUSION

Increased awareness of the underlying factors common to most cases of the missed diagnosis of appendicitis on CT and increased radiologic vigilance in cases of atypical abdominal pain may enable us to further improve our diagnostic accuracy.

MR imaging of the normal appendix and acute appendicitis

PURPOSE

To describe the MR appearance of the normal appendix and the MR imaging characteristics of acute appendicitis with correlation to pathological severity.

MATERIALS AND METHODS

A total of 20 volunteers participated in this study to demonstrate normal appendices by MR imaging. A total of 37 consecutive patients with clinically diagnosed acute appendicitis were also scanned. T1-weighted (T1WI) spin-echo images, T2-weighted (T2WI) fast spin-echo, and fat-suppressed spectral presaturation inversion recovery T2-weighted (T2SPIR) fast spin-echo images were obtained. The MR criteria for considering acute appendicitis were as follows: 1) thickening of the appendiceal wall with high intensity on T2WI or T2SPIR; 2) dilated lumen filled with high intensity material on T2WI or T2SPIR; and 3) increased intensity of periappendiceal tissue on T2WI or T2SPIR.

RESULTS

The visibility of a normal appendix on MR imaging was 90% (18/20). It appeared as a cord-like structure of medium intensity without fluid collection in the lumen. A total of 30 cases with clinically diagnosed acute appendicitis had positive MR findings and all except one were pathologically proven. The one had cecal diverticulitis. These cases demonstrated filled lumen, with a hypointense wall on T1WI and slightly hyperintense on T2WI or T2SPIR. MR findings correlated well with pathological severity, especially a thicker wall, periappendiceal high intensity, and ascites were useful for suspecting severe appendicitis.

CONCLUSION

Correct diagnosis of acute appendicitis was obtained with MRI, and correlated well with its pathological severity. MRI is a powerful alternative for diagnosing acute appendicitis especially for the patients in whom the radiation is major concern.

Diagnosing suspected acute nonclassic appendicitis with sulesomab, a radiolabeled antigranulocyte antibody imaging agent

PURPOSE

The aim of this study was to investigate the potential role of a technetium 99m-labeled antigranulocyte murine antibody Fab' fragment (sulesomab) as a diagnostic imaging agent in children with suspected acute nonclassic appendicitis.

METHODS

Serial planar images at 15 to 30 minutes, 1, 2, and 4 hours and single-photon emission computed tomography (SPECT) images were acquired after sulesomab injection. In 40 children with suspected acute nonclassic appendicitis, imaging results were confirmed surgically in 21 patients, whereas 19 nonsurgical patients resolved presenting signs and symptoms and were considered to not have appendicitis.

RESULTS

Sulesomab imaging had 95% sensitivity, 90% specificity, 95% negative predictive value, and 90% positive predictive value for acute appendicitis. In 78% of patients, sulesomab accurately detected or excluded acute appendicitis and would have changed management plans. No patients had adverse events, and no human antimurine antibody response occurred in 18 evaluable patients.

CONCLUSIONS

Sulesomab was well tolerated with no side effects and with no apparent immunogencity. Appendicitis was rapidly and accurately detected. In pediatric patients with suspected nonclassic appendicitis, management decisions incorporating sulesomab imaging provided benefit in separating surgical from nonsurgical patients.

Sonography of acute appendicitis

Graded compression sonography is an established imaging modality in the clinical setting of acute right lower quadrant pain or to diagnose acute appendicitis because of its easy assessability, noninvasiveness, real-time imaging. However, the ability to accurately diagnose appendicitis can be affected by several factors including operator dependence, deeper-located appendix, and obesity or muscularity of the patient. However, adjuvant techniques utilizing advanced equipment and accumulated operator's experience to conventional graded compression sonography will yield more frequent detection of the vermiform appendix and more accurate results of acute appendicitis on sonography. This article introduces adjuvant techniques and various know-how of real field in the detection of the vermiform appendix and diagnosis of acute appendicitis.

US as a primary diagnostic tool in relation to negative appendectomy: six years experience

PURPOSE

To evaluate the effect of ultrasonography (US) on the rate of appendectomy after false-positive diagnosis of acute appendicitis (negative appendectomy).

MATERIALS AND METHODS

Data were analyzed in 736 pediatric patients (mean age, 13.2 years) who had undergone appendectomy between 1995 and 2000. Histologic data were compared in patients who underwent US with those who did not undergo imaging prior to surgery. US was performed by a radiologist or a pediatric surgeon or both.

RESULTS

A total of 643 (87.4%) of the 736 pediatric patients underwent preoperative US, and 93 (12.6%) of the 736 did not undergo preoperative US. Of the 736 patients, 97 (13.2%) underwent negative appendectomy. Thirty-four (36.6%) of the 93 patients who underwent appendectomy with no preoperative US and 63 (9.8%) of the 643 patients who underwent preoperative US underwent negative appendectomy. There was a significant association between US and positive appendectomy (P <.001).

CONCLUSION

US in pediatric patients suspected of having appendicitis can significantly lower the negative appendectomy rate.

Appendicitis: should diagnostic imaging be performed if the clinical presentation is highly suggestive of the disease?

BACKGROUND & AIMS

Our aim was to investigate whether diagnostic imaging is required if the clinical presentation suggests acute appendicitis with high probability.

METHODS

On the basis of clinical findings, 350 consecutive patients with clinical suspicion of acute appendicitis were prospectively divided into 3 groups as follows: low, intermediate, and high probability of having appendicitis. All patients then underwent diagnostic ultrasonography. The clinical likelihood of appendicitis and the ultrasonographic results were correlated with the definite diagnoses.

RESULTS

In the patients with clinically low probability of having appendicitis, appendicitis was present in 10% (11 of 109 patients), and, in those with intermediate probability, appendicitis was present in 24% (23 of 97 patients). Patients with clinically high probability of having appendicitis had appendicitis in 65% (94 of 144 patients), an alternative diagnosis in 18% (26 of 144 patients), and no specific definitive diagnosis in 17% (24 of 144 patients). Ultrasonography diagnosed appendicitis and the differential diagnoses with a sensitivity of 98% and 97%, specificity of 98% and 100%, positive predictive value of 96% and 99%, negative predictive values of 99% and 99%, and accuracy of 98% and 99%, respectively.

CONCLUSIONS

Even in patients with clinically high probability of acute appendicitis, diagnostic imaging should be performed because it accurately depicts a high percentage of normal appendices and differential diagnoses.

Appendicitis: spectrum of appearances on helical CT

Acute appendicitis has extremely varied clinical presentations. A delayed or missed diagnosis may result in severe adverse consequences. Helical CT is evolving as an important diagnostic aid, but the CT signs can be varied and can easily be overlooked by the unwary. This pictorial review illustrates the spectrum of radiological signs and appearances of appendicitis on helical CT.

CT of appendicitis in children

Appendicitis is the most common condition requiring intraabdominal surgery in infancy and childhood. Yet, despite its common occurrence, accurate diagnosis remains challenging. Acute appendicitis may be missed at initial clinical examination in 28%-57% of children aged 12 years and younger and in nearly 100% of children under the age of 2 years. Diagnostic imaging has an ever-increasing role in the prompt and accurate diagnosis of acute appendicitis in the pediatric population. At the authors' institution, helical computed tomography (CT) is the primary tool for diagnosing or excluding appendicitis in children. Since its inception in 1998, helical CT with rectally administered contrast material has been shown to reduce the total number of inpatient observation days, laparotomies with negative findings, and per-patient cost. Helical CT is a highly sensitive and specific tool for diagnosing pediatric appendicitis and has resulted in a beneficial change in patient care in 68.5% of all patients seen in the authors' emergency department for suspected appendicitis. This includes both those patients who receive an eventual diagnosis of appendicitis and those who do not have the disease. Major strengths of limited helical CT with rectal contrast material include producing uniformly high published sensitivity and specificity values for diagnosis of appendicitis and enabling diagnosis of alternative conditions of acute abdominal pain in children. In contrast, limitations of graded-compression ultrasonography in children include highly operator-dependent sensitivity and specificity values and relative infrequency with which the normal appendix can be visualized in this population. Although there have been many exciting diagnostic advancements for the diagnosis of acute appendicitis in the pediatric population, the role of helical CT is far from clear. The purpose of this article is to describe a helical CT approach to imaging in children suspected of having acute appendicitis at a large urban pediatric teaching hospital and its effects on patient outcomes and hospital costs.

CT scan in the management of acute appendicitis

BACKGROUND

Recent studies demonstrate a 98% accuracy of a CT scan in the diagnosis of acute appendicitis. We aimed to determine the accuracy and clinical value of CT scans in patients suspected of having acute appendicitis.

PATIENTS AND MATERIALS

We reviewed outcomes of 125 patients over a 5-month period who had CT scans for the initial diagnosis of acute appendicitis. CT scan interpretations were correlated with surgical and pathologic findings. Follow-up was attempted in all patients who did not undergo appendectomy.

RESULTS

CT scans and clinical courses were complete in 110 patients (88%); 14 patients were lost to follow-up and 1 was excluded. One patient had two CT scans. Thus, there were 111 CT scans available for review. Radiologic interpretation of these CT scans yielded 36 positive (33%), 67 negative (60%), and 8 indeterminate (7%), resulting in a sensitivity of 90%, a specificity of 89%, a PPV of 78%, and a NPV of 96%.

CONCLUSIONS

CT scan may be useful in the diagnosis of acute appendicitis, but the reported high accuracy rate was not reproduced at our institution. CT scan was not clinically useful in 21% of patients. We conclude that a CT scan may be beneficial in the diagnosis of appendicitis with selected patients who have equivocal findings. Thus, at our institution, the accuracy of a CT scan does not justify its routine use in patients with clinical findings of appendicitis.

Effect of contrast-enhanced computed tomography on diagnosis and management of acute abdomen in adults

AIM

To determine the impact of computed tomography (CT) on the diagnosis and treatment plan in patients with acute abdominal pain.

MATERIALS AND METHODS

A prospective study was undertaken in 125 adult patients presenting with acute abdominal pain (74 men and 51 women; 40.2 +/- 19.3 years; range, 18-92). Changes in diagnosis, gain in percentage diagnostic certainty and changes of treatment plan of the surgeons in the emergency department before and after CT were evaluated. Pre- and post-CT diagnoses were compared with the final diagnoses.

RESULTS

CT findings changed the initial diagnosis in 40 (32.0%) patients. The diagnostic certainty was 58.3 +/- 22.9% before CT, and its gain after CT was 21.9 +/- 18.5 points (P < 0.0001). Post-CT diagnoses were consistent with the final diagnosis in 116 patients (92.8%), while pre-CT diagnoses were correct in 89 patients (71.2%; P < 0.0001). Initial treatment plans were changed in 31 (24.8%) patients after CT. In 57 (45.6%) patients, CT information changed diagnoses and/or treatment plans. No significant differences were observed in the diagnosis, diagnostic certainty and treatment plan among four surgeons.

CONCLUSION

Contrast-enhanced CT frequently changed the clinical diagnoses with increased diagnostic certainty and the initial treatment plans.

Graded compression sonography with adjuvant use of a posterior manual compression technique in the sonographic diagnosis of acute appendicitis

OBJECTIVE

We evaluated the usefulness of graded compression sonography with the adjuvant use of a posterior manual compression technique for detection of the vermiform appendix and the diagnosis of acute appendicitis.

SUBJECTS AND METHODS

Five hundred seventy consecutive patients referred for suspected acute appendicitis were prospectively examined by original, graded compression sonography with a 5- or a 7.5-MHz linear transducer. A posterior manual compression technique was added for 85 patients whose vermiform appendix was not identified with graded compression sonography. For consensus, another experienced radiologist or a resident observer was in attendance throughout the examination. The detection rate for the vermiform appendix and the diagnostic accuracy for acute appendicitis before and after the adjuvant use of a posterior manual compression technique were obtained, respectively, and final diagnoses were established with the official radiology reports, surgical results, and clinical follow-up.

RESULTS

Graded compression sonography enabled visualization of the vermiform appendix in 485 (85%) of 570 patients. After the adjuvant use of a posterior manual compression technique, the vermiform appendix was found in an additional 57 of 85 patients, with the number of identified vermiform appendices increasing to 542 (95%) of 570 patients. The 57 patients with an additionally found appendix included 11 patients with acute appendicitis. The sonographic diagnosis of acute appendicitis was determined in 312 of 542 patients. Acute appendicitis was proven by surgery in 311 of 332 patients. Sonography was used to establish the diagnosis in 302 of the 311 patients with proven appendicitis; there were 10 false-positive diagnoses and nine false-negative diagnoses. One false-positive diagnosis was acquired after use of the posterior manual compression technique. These results showed more improvement than those of the probabilities for acute appendicitis with single use of graded compression sonography.

CONCLUSION

Graded compression sonography with adjuvant use of a posterior manual compression technique seems to be useful for detecting the vermiform appendix and for diagnosing acute appendicitis.

Acute appendicitis: comparison of helical CT diagnosis focused technique with oral contrast material versus nonfocused technique with oral and intravenous contrast material

PURPOSE

To compare the diagnostic accuracy of focused helical computed tomography (CT) with orally administered contrast material with that of nonfocused helical CT with orally and intravenously administered contrast material.

MATERIALS AND METHODS

After receiving oral contrast material, 228 patients with clinically suspected appendicitis underwent focused appendiceal CT (5-mm section thickness, 15-cm coverage in the right lower quadrant). Immediately thereafter, helical CT of the entire abdomen and pelvis was performed following intravenous administration of contrast material (abdomen, 7-mm section thickness; pelvis, 5-mm section thickness). Studies were separated and independently interpreted by three observers who were blinded to patient names. Diagnoses were established by means of surgical and/or clinical follow-up findings.

RESULTS

Fifty-one (22.4%) of 228 patients had acute appendicitis. Readers diagnosed appendicitis with 83.3%, 73.8%, and 71.4% sensitivity and 93.0%, 92.3%, and 97.9% specificity with focused nonenhanced appendiceal CT. Readers diagnosed appendicitis with 92.9%, 92.9%, and 88.1% sensitivity and 93.7%, 95.1%, and 96.5% specificity with nonfocused enhanced CT. Summary areas under the receiver operating characteristic curve estimates for focused nonenhanced and nonfocused enhanced CT were 0.916 and 0.964, respectively; the differences were statistically significant (P <.05) for two of three readers. All readers demonstrated higher sensitivities for detecting the inflamed appendix with nonfocused enhanced CT. Appendicitis was missed with focused CT in two patients whose inflamed appendix was not included in the imaging of the right lower quadrant. All readers were significantly more confident in diagnosing alternative conditions with nonfocused enhanced CT.

CONCLUSION

Diagnostic accuracy of helical CT for acute appendicitis improved significantly with use of intravenous contrast material.

Outer diameter of the vermiform appendix as a sign of acute appendicitis: evaluation at US

PURPOSE

To evaluate the usefulness and limitations of the outer diameter of the vermiform appendix at cross-sectional ultrasonography to confirm or rule out acute appendicitis.

MATERIALS AND METHODS

In a prospective study, outer appendiceal diameters in 240 control subjects and in 278 patients suspected of having acute appendicitis who did (n = 98) or did not (n = 180) have acute appendicitis were measured.

RESULTS

Outer appendiceal diameters in the control subjects ranged between 2 and 13 mm, and in 55 (23%) of 240 control subjects, diameters were 6 mm or more. Diameters in the symptomatic patients without acute appendicitis ranged between 2 and 11 mm, and 57 (32%) of 180 patients had diameters of 6 mm or more. Diameters of acutely inflamed appendices ranged between 6 and 30 mm. A diameter of 6 mm or more confirmed acute appendicitis with a sensitivity of 100%; a specificity of 68%; positive and negative predictive values of 63% and 100%, respectively; and an accuracy of 79%.

CONCLUSION

The outer appendiceal diameter of 6 mm or more as a sign of acute appendicitis provides high sensitivity but limited specificity. This diagnostic criterion is more useful in excluding acute appendicitis than in confirming it.

Reflections: emergency radiology

In this article, the author compares emergency radiology as it was practiced and taught from the turn of the 20th century to the middle 1970s with the way it is practiced and taught today. Many specific examples are cited. External influences serendipitously converged in the 1960s-1980s, and their effect on the evolution of emergency radiology as it is recognized today are described.

The value of limited computed tomography with rectal contrast in the diagnosis of acute appendicitis

BACKGROUND

Multiple nonrandomized studies demonstrate the accuracy of computed tomography (CT) scan in diagnosing appendicitis. This study compared CT scan with standard management in diagnosing appendicitis.

METHODS

This was a prospective randomized study of patients who received general surgery consultation for appendicitis. Patients were randomized to receive CT scan or standard management.

RESULTS

There were 65 patients in the CT scan group and 63 patients in the standard management group. The sensitivity, specificity, and accuracy of CT scan were 94%, 100%, and 96%, respectively. CT scan positively altered the management in 26% and made alternative diagnoses in 14%. The sensitivity, specificity, and accuracy of the standard management group were 100%, 79%, and 89%, respectively. The standard management group had a negative appendectomy rate of 19%.

CONCLUSION

CT scan with rectal contrast is an effective method for diagnosing appendicitis and should be performed in all patients suspected of having appendicitis.

Tailored helical CT evaluation of acute abdomen

Helical computed tomography (CT) allows rapid, cost-effective evaluation of patients with acute abdominal pain. Tailoring the examination to the working clinical diagnosis by optimizing constituent factors (eg, timing of acquisition, contrast material used, means and rate of contrast material administration, collimation, pitch) can markedly improve diagnostic accuracy. Rapid (>/=3 mL/sec) intravenous injection of contrast material is required for optimal assessment of acute pancreatitis, ischemic bowel, aortic aneurysm, and aortic dissection. Narrow collimation and small reconstruction intervals can help detect calculi in the biliary system and genitourinary tract. Tailored helical CT in patients with acute pyelonephritis usually involves several acquisitions through the kidneys during various phases of renal enhancement. In patients with suspected renal infarction, CT protocol must include an acquisition during the corticomedullary phase. Helical CT with 5-mm collimation through the lower abdomen and pelvis is used to evaluate patients with suspected diverticulitis. Use of both oral and intravenous contrast material can help localize small bowel perforation and characterize related complications. Tailored helical CT for assessment of abdominal hemorrhage consists of initial unenhanced CT followed by optional contrast material-enhanced CT. Clear communication between the radiologist, the patient, and the referring physician is essential for narrowing the differential diagnosis into a working diagnosis prior to helical CT.

CT evaluation of the colon: inflammatory disease

Computed tomography (CT) is valuable for detection and characterization of many inflammatory conditions of the colon. At CT, a dilated, thickened appendix is suggestive of appendicitis. A 1-4-cm, oval, fatty pericolic lesion with surrounding mesenteric inflammation is diagnostic of epiploic appendagitis. The key to distinguishing diverticulitis from other inflammatory conditions of the colon is the presence of diverticula in the involved segment. In typhlitis, CT demonstrates cecal distention and circumferential thickening of the cecal wall, which may have low attenuation secondary to edema. In radiation colitis, the clinical history is the key to suggesting the diagnosis because the CT findings can be nonspecific. The location of the involved segment and the extent and appearance of wall thickening may help distinguish Crohn disease and ulcerative colitis. In ischemic colitis, CT typically demonstrates circumferential, symmetric wall thickening with fold enlargement. CT findings of graft-versus-host disease include small bowel and colonic wall thickening, which may result in luminal narrowing and separation of bowel loops. In infectious colitis, the site and thickness of colon affected may suggest a specific organism. The amount of wall thickening in pseudomembranous colitis is typically greater than in any other inflammatory disease of the colon except Crohn disease.

Computed tomography in the diagnosis of equivocal appendicitis

BACKGROUND

The clinically obscure right iliac fossa (RIF) pain remains a diagnostic problem. The present study examines the use of computed tomography (CT) in improving the accuracy of clinical assessment in these difficult surgical cases.

METHODS

The trial design was a retrospective review of all patients admitted under one surgeon with suspected acute appendicitis, between 1 January 1995 and 30 June 1997. The study setting was a district hospital (Calvary Hospital) that received patients from both an urban and rural environment. The patient cohort was identified from the Unit Registry and an International Classification of Diseases-based review of medical records. Twenty-one prospective data points were obtained from patient records. Those patients admitted with RIF pain and equivocal symptoms and signs subsequently underwent a CT and/or ultrasound (US) examination, conducted by the attending radiologist. For those patients who proceeded to appendicectomy, the histopathological findings were correlated with the imaging report. Those patients who were discharged after imaging without proceeding to operation were not readmitted to any regional hospital during the course of the study.

RESULTS

A total of 84 patients were identified. Thirty-three patients (39%) underwent appendicectomy without imaging and were excluded from further analysis. A total of 51 patients (61%) underwent 61 imaging procedures. The CT scan was correct in 35/36 patients (97%), while US was correct in 17/25 patients (68%).

CONCLUSIONS

The present study suggests that CT can be used to improve the accuracy of diagnosis of obscure RIF pain. As a pilot study, it supports the development of a randomized controlled trial in a multicentre regional study.

Unenhanced CT in the evaluation of the acute abdomen: the community hospital experience

The "Great Mimicker," acute appendicitis, has finally found its match with the advent of rapid unenhanced computed tomography (RUCT). With little, if any, operator dependence, RUCT can be performed easily at any facility that has CT capabilities. With only minimal interpreter dependence, the examination is highly accurate in determining which patients with acute abdominal pain require further treatment and expenditure of resources. In this article we describe our experience, since devising the technique in 1991, with over 7,000 RUCT scans done on patients with acute abdominal pain, predominantly in the right lower quadrant. We show how RUCT is extremely useful and accurate, not only in the diagnosis of acute appendicitis, but in many other disease entities that mimic the "Great Mimicker."

Intestinal (mesenteric) vasculopathy. I. Acute superior mesenteric arteriopathy and venopathy

Intestinal vasculopathy is not rare, comprising about 1 per 1000 hospital admissions. Primary mesenteric vasculopathy causes cardiovascular disease, whereas secondary mesenteric ischemia causes extrinsic vascular compression or vascular trauma. Acute superior mesenteric arteriopathy is caused by a mesenteric embolus, thrombus, or vasospasm (i.e., nonocclusive vasculopathy). Acute superior mesenteric venopathy is caused by a thrombus, which is often associated with a hypercoagulopathy. The clinical presentation of both diseases is often subtle and nonspecific at an early stage and becomes overt and specific only when advanced and severe, when ischemia progresses to necrosis. The mortality of acute superior mesenteric arteriopathy is still very high, whereas superior mesenteric venopathy is less rapidly progressive and has a lower, but still significant, mortality. Early diagnosis and aggressive therapy significantly reduces the mortality of these life-threatening diseases.

The value of unenhanced CT in the diagnosis of acute appendicitis

OBJECTIVE

To establish the accuracy of unenhanced CT in the preoperative diagnosis of acute appendicitis.

DESIGN

Accuracy study, prospective and blinded.

SETTING

The University Hospital.

PARTICIPANTS

52 patients with clinical and laboratorial manifestations of acute appendicitis. CT diagnosis was made by: presence of an abnormal appendix, appendiceal calculi with pericecal phlegmon or alterations in the pericecal appendicular site and absence of signs that may lead to other diagnosis.

MAIN OUTCOME MEASURES

Overall accuracy, comparing the tomographic aspects with the intra-operative findings and pathological reports ("gold standard").

RESULTS

Acute appendicitis was confirmed in 44 cases. Efficacy was 92%, sensitivity was 91%, specificity was 100%, positive predictive value was 100% and negative predictive value was 67%.

CONCLUSIONS

Unenhanced CT presents a similar overall accuracy to that reported by other authors who studied enhanced CT diagnosis of acute appendicitis.

CT of appendicitis in children

PURPOSE

Our goal was to review the CT findings and to help define the role of CT in the evaluation of appendicitis in children.

METHOD

Of 730 children with surgically proven appendicitis, 22 underwent preoperative CT evaluation. Their CT scans and operative and pathology records were retrospectively reviewed. The CT scans were evaluated for appendiceal wall thickness, diameter, and location, appendicoliths, pericecal inflammation, phlegmon, abscess, free fluid, small bowel dilatation, and bowel wall thickening. Criteria for diagnosing appendicitis were (a) appendiceal wall thickening (> 1 mm) or (b) presence of abscess, phlegmon, or pericecal inflammation associated with appendicolith(s). Prospective reports of ultrasound examinations performed within 2 days of the CT scans were available in 14 children and were correlated with the CT findings.

RESULTS

An abnormally thickened appendix, with a diameter ranging from 9 to 18 mm, was seen in four children. Three appendices were retrocecal and one was near the cecal tip, anterior to the iliac vessels. Appendicoliths were present in 10 children, multiple in 1. Abscesses were seen in 13 of 22 children, multiple in 5. Phlegmon was seen in five children and pericecal inflammation in two. Bowel wall thickening was present in seven children and small bowel dilatation was noted in six. Other findings included free fluid, hydronephrosis, thickening of urinary bladder wall, air in the uterus and vagina, adenopathy, and thickening of the abdominal wall musculature. CT was diagnostic of appendicitis in 11 of 22 children (50%). In 14 children with both ultrasound and CT studies, CT was slightly better in diagnosing appendicitis and visualizing the abnormal appendix and was superior in defining the presence and extent of abscess and inflammation in 9 of 14 children.

CONCLUSION

CT is a useful adjunct in diagnosing appendicitis in children, with a major role in cases of complicated appendicitis.