Appendiceal Perforation Research Articles

Effect of Race and Socioeconomic Status in the Treatment of Appendicitis in Patients With Equal Health Care Access

Lower socioeconomic and minority racial/ethnic status have been linked to delays in surgical care and thus higher appendiceal perforation rates. Equal access to health care eliminates the previously reported socioeconomic and racial/ethnic disparities in rates of appendiceal perforation. Retrospective cohort study using discharge abstract data and US census data. Twelve regional Kaiser Permanente hospitals in southern California. A total of 16,156 patients treated for appendicitis. Patients were divided into low, medium, and high groups based on annual household income and educational level, as well as racial/ethnic status (white, black, Hispanic, and Asian). Appendiceal perforation (AP) rate and length of hospitalization (LOH). The adjusted odds ratio for AP was lower in Hispanics and similar in blacks and Asians compared with whites. The odds ratio for AP was similar in high- and medium-income families compared with low-income families. The odds ratio for AP was higher in patients with high educational levels and similar in those with medium educational levels compared with low educational levels. The adjusted LOH was longer in blacks, shorter in Hispanics, and similar in Asians compared with whites. The LOH was similar in high- and medium-income families compared with low-income families. The LOH was higher in patients with medium educational levels and similar in those with high educational levels compared with low educational levels. Lower socioeconomic background and minority race/ethnicity did not correlate with higher AP rates or a clinically longer LOH in patients with equal access to care. Based on these findings, we believe that equal health care access leads to equivalent outcomes in all patients with appendicitis.

Impact of computed tomography of the abdomen on clinical outcomes in patients with acute right lower quadrant pain: a meta-analysis

Clinical evaluation alone is still considered adequate by many clinicians who treat patients with appendicitis. The impact of computed tomography (CT) on clinical outcomes remains unclear, and there is no consensus regarding the appropriate use of CT in these patients. We sought to evaluate the impact of abdominal CT on the clinical outcomes of patients presenting with suspected appendicitis. We conducted a systematic review of the literature to identify studies that examined clinical outcomes related to the use of abdominal CT in the diagnosis of acute appendicitis. Inclusion criteria were studies of adult patients with suspected appendicitis that evaluated the impact of abdominal CT on negative appendectomy rates, perforation rates or time to surgery. Two independent investigators reviewed all titles and abstracts and extracted data from 28 full-text articles. Statistical analysis was conducted using Review Manager 5.0.10 software. The negative appendectomy rate was 8.7% when using CT compared with 16.7% when using clinical evaluation alone (p < 0.001). There was also a significantly lower negative appendectomy rate during the CT era compared with the pre-CT era (10.0% v. 21.5%, p < 0.001). Time to surgery was evaluated in 10 of the 28 studies, 5 of which demonstrated a significant increase in the time to surgery with the use of CT. Appendiceal perforation rates were unchanged by the use of CT (23.4% in the CT group v. 16.7% in the clinical evaluation group, p = 0.15). Similarly, the perforation rate during the CT era was not significantly different than that during the pre-CT era (20.0% v. 19.6%, p = 0.74). This meta-analysis supports the hypothesis that the use of preoperative abdominal CT is associated with lower negative appendectomy rates. The use of CT in the absence of an expedited imaging protocol may delay surgery, but this delay is not associated with increased appendiceal perforation rates. Routine CT in all patients presenting with suspected appendicitis could reduce the rate of unnecessary surgery without increasing morbidity.

The value of hyperbilirubinaemia in the diagnosis of acute appendicitis

INTRODUCTION No reliably specific marker for acute appendicitis has been identified. Although recent studies have shown hyperbilirubinaemia to be a useful predictor of appendiceal perforation, they did not focus on the value of bilirubin as a marker for acute appendicitis. The aim of this study was to determine the value of hyperbilirubinaemia as a marker for acute appendicitis. MATERIALS AND METHODS A retrospective analysis of appendicectomies performed in two hospitals (n=472). Data collected included laboratory and histological results. Patients were grouped according to histology findings and comparisons were made between the groups. RESULTS The mean bilirubin levels were higher for patients with simple appendicitis compared to those with a non-inflamed appendix (p<0.001). More patients with simple appendicitis had hyperbilirubinaemia on admission (30% vs 12%) and the odds of these patients having appendicitis were over three times higher (odds ratio: 3.25, p<0.001). Hyperbilirubinaemia had a specificity of 88% and a positive predictive value of 91% for acute appendicitis. Patients with appendicitis who had a perforated or gangrenous appendix had higher mean bilirubin levels (p=0.01) and were more likely to have hyperbilirubinaemia (p<0.001). The specificity of hyperbilirubinaemia for perforation or gangrene was 70%. The specificities of white cell count and C-reactive protein were less than hyperbilirubinaemia for simple appendicitis (60% and 72%) and perforated or gangrenous appendicitis (19% and 36%). CONCLUSIONS Hyperbilirubinaemia is a valuable marker for acute appendicitis. Patients with hyperbilirubinaemia are also more likely to have appendiceal perforation or gangrene. Bilirubin should be included in the assessment of patients with suspected appendicitis.

Duplicated appendix complicated by appendiceal cancer

A 37-year old male presented with an acute abdomen suggestive of an appendiceal perforation. Urgent laparotomy showed a duplicated appendix with one of the lumens involved with appendicitis and a focal peri-appendicular abscess while the other lumen had a localized appendiceal cancer. Recognition of congenital intestinal duplications in adults is important to avoid serious clinical consequences.

Effect of delay in presentation on rate of perforation in children with appendicitis

Introduction Appendicitis is the most common emergency operation in children. The rate of perforation may be related to duration from symptom onset to treatment. A recent adult study suggests that the perforation risk is minimal in the first 36 hours and remains at 5% thereafter. We studied a pediatric population to assess symptom duration as a risk factor for perforation. Methods We prospectively studied all children older than 3 years who underwent an appendectomy over a 22-month period. Results Of 202 patients undergoing appendectomies, 197 had appendicitis. Median age was significantly lower in the perforated group, but temperature and leukocytosis were not. As expected, length of hospital stay was longer in the perforated group (4-13 vs 2-6 days). The incidence of perforation was 10% if symptoms were present for less than 18 hours. This incidence rose in a linear fashion to 44% by 36 hours. Prehospital delays were greater in patients with perforated appendicitis. However, in-hospital delay (from presentation to surgery) was less than 5 hours in the perforated group and 9 hours in the nonperforated group. Discussion Appendiceal perforation in children is more common than in adults and correlates directly with duration of symptoms before surgery. Perforation is more common in younger children. Unlike in adults, the risk of perforation within 24 hours of onset is substantial (7.7%), and it increases in a linear fashion with duration of symptoms. In our experience, however, perforation correlates more with prehospital delay than with in-hospital delay.

Perforated appendicitis in children: equal access to care eliminates racial and socioeconomic disparities

Purpose The aim of the study was to determine whether equal access to health care eliminates racial and socioeconomic disparities in appendicitis outcomes. Methods A review of patients younger than 18 years treated for appendicitis for a decade was performed. Outcomes were appendiceal perforation (AP) rate and length of hospitalization (LOH). Independent variables included racial status, annual median per capita income, and parental education level. Results Seven thousand two hundred forty-seven patients were identified (mean age, 11.6 years; 62% male). The adjusted odds ratio (OR) for AP was similar in blacks, Hispanics, and Asians compared to whites. The OR for AP was similar in high- and medium-income families compared to low-income families. The OR for AP was similar in high and medium parental education levels compared to low parental education levels. The adjusted LOH was longer in blacks and similar in Hispanics and Asians compared to whites. The LOH was shorter in high- and similar in medium-income families compared to low-income families. The LOH was similar in all parental education levels. Conclusion Lower socioeconomic background and minority status did not correlate with higher appendiceal perforation rates or a clinically longer LOH in children with equal access to care. The previously reported disparities in pediatric appendicitis outcome are preventable with equal access to care.

Comparison of Intra-Abdominal Abscess Formation Following Laparoscopic and Open Appendicectomy in Children

Controversy exists over the association between laparoscopic (LA) and open appendicectomy (OA) and the formation of postoperative intra-abdominal abscesses (IAAs). Our aim was to compare the outcome following these two techniques in a pediatric population. A retrospective data collection was carried out on all patients undergoing either an LA or OA at a single center over a 26-month period. Patients were identified from a hospital database and theater records. An intra-abdominal abscess was defined as recorded pyrexia, a raised inflammatory marker, and radiologic confirmation of an intra-abdominal collection. Other parameters studied included wound infection, appendiceal perforation, hospital stay, conversion rate, microbiology, histology, radiologic investigation, and serologic analysis. Data were analyzed from using Fisher's exact and Mann-Whitney tests, as appropriate. A P-value of <0.05 was considered significant. Two hundred children were identified, with a median follow-up of 18 months. Forty patients underwent an LA and 151 an OA. Nine patients underwent interval appendicectomy and were not included in the final data. There was no difference between the two groups in terms of baseline demographics, duration of stay (P = 0.5), or wound infection (P = 1.0). The incidence of an intra-abdominal abscess was 0 of 40 (0%) in the laparoscopic group and 5 of 151 (3.3%) in the open group, although this was not statistically significant (P = 0.8). The median time to postoperative diagnosis of abscess was 9 days (range, 8-11). A consultant was present in more laparoscopic procedures than open (88 versus 24%; P = 0.0001). The rate of intra-abdominal abscess formation was not significantly different following either an LA or OA, although there were no intra-abdominal abscesses observed in the laparoscopic group. Further investigation could address this finding more accurately in a randomized, controlled trial.

“July Effect” and Appendicitis

Patients at teaching hospitals often worry about the involvement of inexperienced surgical residents in their care. The most apparent time that physician inexperience would affect surgical outcomes would be in July, which is the start of residency training. The purpose of our study was to determine whether the morbidity related to the management of appendicitis was higher in the beginning of the academic year. A retrospective review of all appendicitis cases between 1998 and 2007 at 2 public teaching hospitals was conducted. An analysis was performed comparing all appendicitis cases in July/August versus all other months of the academic year. The outcome variables were wound infection rate, postoperative abscess drainage rate, and length of hospitalization (LOH). A total of 4325 patients were included in the study. Patient demographics and appendiceal perforation rate were similar between July/August and the rest of the year. Wound infection rate, postoperative abscess drainage rate, and LOH were also similar between these 2 time periods. Appendicitis outcomes were similar in the beginning of the academic year in comparison with the remaining months. These findings suggest that patients with acute appendicitis can safely undergo emergency surgery early in the training year.

Accuracy of computed tomography in predicting appendiceal perforation

Background Some surgeons use nonoperative management with or without interval appendectomy for patients who present with perforated appendicitis. These strategies depend on accurately delineating perforation by computed tomography (CT). Since 2005, our institution has used an evidence-based definition for perforation as a hole in the appendix or fecalith in the abdomen. This has been shown to clearly separate those with a high risk of abscess from those without. To quantify the ability of CT to identify which patients would meet these criteria for perforation, we tested 6 surgeons and 2 radiologists who evaluated blinded CT scans. Methods A junior and senior surgical residents, 2 staff interventional radiologists, and 4 attending pediatric surgeons with 3 to 30 years of experience reviewed 200 CT scans of pediatric patients who had undergone a laparoscopic appendectomy. All CT scans were reviewed electronically, and the reviewers were blinded to the results, outcome, and intraoperative findings. None of the patients had a well-formed abscess on CT. The reviewers were asked to decide only on perforated or nonperforated appendicitis according to our intraoperative definition. Clinical admission data were reviewed and compared between groups. Results In total, the reviewers were correct 72% of the time with an overall sensitivity of 62% and a specificity of 81%. The overall positive predictive value was 67%, and the negative predictive value was 77%. Conclusions This study shows that in the absence of a well-formed abscess, the triage of patient care based on a preoperative diagnosis of perforation from CT may be imprudent and subject a portion of the population to an unnecessarily prolonged course of care.

Incidence and management of bevacizumab-associated gastrointestinal perforations in patients with recurrent ovarian carcinoma

Objective The objective of this study was to examine the incidence and management of bevacizumab-associated gastrointestinal (GI) perforations in patients with recurrent ovarian carcinoma. Methods We identified all patients who received bevacizumab off protocol from August 2004–August 2008. We examined their medical records for reports of confirmed GI perforation, associated clinicopathological factors, treatment, and outcomes. Results Six (4%) of 160 patients with ovarian carcinoma who had been treated with bevacizumab developed GI perforations, with a median of 4 (range, 2–8) previous cytotoxic regimens. The median serum CA-125 at the start of treatment was 228 U/mL (range, 50–3106 U/mL). The median number of bevacizumab cycles prior to perforation was 10.5 (range, 2–20). The median time from the last bevacizumab dose to diagnosis of GI perforation was 13 days (range, 1–28 days). Four (67%) patients underwent an exploratory surgery. At laparotomy, one had a gastric perforation and one had an appendiceal perforation; the site of perforation could not be identified in the other 2 Two patients (33%) were managed conservatively—one with a PEG tube and the other with supportive care. The median time of death from the date of diagnosis of GI perforation was 27 days (range, 4–326 days). Only two patients—one with a gastric and the other with an appendiceal perforation—survived > 65 days. The 30-day mortality rate following a bevacizumab-associated GI perforation was 50%. Conclusion Bevacizumab-associated GI perforations in patients with recurrent ovarian carcinoma occurred in 4% of our patients. The prognosis of patients diagnosed with bevacizumab-associated GI perforations in this study was poor, and treatment should be individualized.

Epidemiology of Appendectomy and Appendicitis in the Valencian Community (Spain), 1998–2007

Background/Aims: Our purpose was to study the incidence of appendectomy and appendicitis in the Valencian community (Spain) during a period of 10 years (1998–2007). Methods: Data on discharge diagnoses of appendectomy and appendicitis were downloaded from all public hospitals in the Valencian community. Results: We identified 44,683 cases of appendectomies and 42,742 cases of appendicitis (95.7%) during the study period. The age-standardized incidence rates among men ranked between 132.1 cases per 100,000 population in 2003 and 117.46 cases per 100,000 population in 2000 without a clear trend through the study period. The appendiceal perforation rate was 12.1% and the negative appendectomy rate 4.3%. The global mortality was 0.38%. Conclusions: The incidence of appendectomy in our community presents a slight descending trend. This decline is more intense in females. The appendix perforation rate is lower than in other studies. The death rate is similar to other studies; however, it is very low in patients of younger age.

CT Protocols for Acute Appendicitis: Time for Change

AJR:193, November 2009 optimal for imaging patients with suspected acute appendicitis. This is an important issue because IV contrast administration is associated with increased examination cost; increased patient discomfort; risk of allergic reaction [12]; risk of tissue injury if extravasation occurs [13]; and risk of renal insufficiency [14], which rarely occurs. Positive oral contrast ingestion is inconvenient for the patient and requires a delay to allow the ingested contrast medium to pass into the cecum [15]. During the time interval between the initial clinical evaluation and subsequent CT examination after oral contrast ingestion, patients might be at risk for appendiceal perforation. Furthermore, emergency departments are closely scrutinized to decrease length of stay. Standard-dose CT exposes patients to radiation, which is a concern particularly given that appendicitis is common, with a lifetime risk of 8.6% for men and 6.7% for women [16]; moreover, there is a trend toward increased use of CT [17], and many patients with suspected acute appendicitis are young [16]. If a low-dose protocol without IV or oral contrast material had an accuracy similar to that of the traditional protocol, patients with suspected acute appendicitis would benefit. Recent work highlighted in the AJR from Belgium [18], Korea [19], and the United States [20] provides compelling evidence that a low-radiation-dose protocol without oral or IV contrast material may be adequate for the diagnosis of acute appendicitis. The time for change may be upon us. Keyzer et al. [18] randomized patients to ingest or not ingest positive oral contrast medium. Thereafter, all patients underwent both unenhanced and IV contrast-enhanced scanning. CT Protocols for Acute Appendicitis: Time for Change

CT Evaluation of Acute Appendicitis

To make the clinical diagnosis of acute appendicitis can be a challenge. In premenopausal women and older adults, a variety of conditions, including gynecologic pathology, can mimic the symptomatology of acute appendicitis.1 Presently, radiologists increasingly are called upon to make the diagnosis of acute appendicitis at CT, with 88% of patients undergoing CT prior to appendectomy in a recent series.2 In the following review, we will discuss the CT appearance of the normal and acutely inflamed appendix, CT findings of appendiceal perforation, mimics of acute appendicitis at CT, the significance of the nonvisualized appendix, and the role of CT in patient management. Only the adult patient is covered in this review.

A Prospective Bicenter Study Investigating the Diagnostic Value of Procalcitonin in Patients with Acute Appendicitis

Background: Procalcitonin (PCT) is an established laboratory marker for disease severity in patients with infection and sepsis. In addition, PCT has been shown to be an effective marker for a limited number of localized infections. However, whether or not PCT has any diagnostic value for acute appendicitis, still remains unclear. The purpose of this prospective bicenter study was, therefore, to determine whether or not the PCT levels in the serum of patients with acute appendicitis have any diagnostic value. Methods: This prospective study included 103 patients who received an appendectomy, based on the clinical diagnosis of acute appendicitis, in a surgical department of an academic teaching hospital in Germany or in a county hospital in Spain. White blood cell count (WBC), C-reactive protein (CRP) and procalcitonin (PCT) values were determined preoperatively. All appendectomy specimens were sent for routine histopathological evaluation. Based on this information, the patients were assigned to 1 of 5 groups that reflected the severity of the appendicitis. Results: Of the 103 patients who were included in the study, 98 had appendicitis. Fourteen (14.3%) showed an increase in PCT values. Of those 14, 4 had a serum PCT >0.5 ng/ml, 9 had a PCT value >2–10 ng/ml and 1 had a PCT value >10 ng/ml. The sensitivity of PCT was calculated to be 0.14. The mean WBC value was 13.0/nl (± 5.2, 3.4–31), and for CRP it was 8.8 mg/dl (± 13, 0–60.2). The values of CRP, WBC and PCT increased with the severity of the appendicitis. Conclusions: PCT is potentially increased in rare cases of severe inflammation and, in particular, after appendiceal perforation or gangrenous appendicitis. However, its remarkably low sensitivity prohibits its routine use for the diagnosis of appendicitis.

Access to emergency operative care: A comparative study between the Canadian and American health care systems

Canada provides universal health insurance to all citizens, whereas 47 million Americans are uninsured. There has not been a study comparing access to emergency operative care between the 2 countries. As both countries contemplate changes in health care delivery, such comparisons are needed to guide health policy decisions. The purpose of this study is to determine whether or not there is a difference in access to emergency operative care between Canada and the United States. All patients diagnosed with acute appendicitis from 2001 to 2005 were identified in the Canadian Institute for Health Information database and the US Nationwide Inpatient Sample. Severity of appendicitis was determined by ICD-9 codes. Patients were further characterized by age, gender, insurance status, race, and socioeconomic status (SES; income). Univariate and multivariate analyses were performed to determine the odds of appendiceal perforation at different levels of SES in each country. There were 102,692 Canadian patients and 276,890 American patients with acute appendicitis. In Canada, there was no difference in the odds of perforation between income levels. In the United States, there was a significant, inverse relationship between income level and the odds of perforation. The odds of perforation in the lowest income quartile were significantly higher than the odds of perforation in the highest income bracket (odds ratio, 1.20; 95% confidence interval, 1.16-1.24). The results suggest that access to emergency operative care is related to SES in the United States, but not in Canada. This difference could result from the concern over the ability to pay medical bills or the lack of a stable relationship with a primary care provider that can occur outside of a universal health care system.

CT Scans and Acute Appendicitis: A Five-Year Analysis from a Rural Teaching Hospital

IntroductionStudies examining the relationship between computed tomography (CT) scans and appendiceal perforation have largely been conducted in urban centers. The present study sought to evaluate this relationship in a rural hospital. Methods and ProceduresThis is a retrospective analysis of 445 patients who underwent appendectomies from January 2000 to June 2005 at a rural teaching hospital. ResultsFour hundred forty-five patients were analyzed in two groups; those who underwent CT scans (N = 245) and those who did not (N = 200). Patients undergoing CT scans were significantly older (median age 38 vs. 22 years, P < 0.0001), were more likely to have perforated appendicitis (P 0.001), were less likely to undergo a negative appendectomy (P = 0.003), and had a significantly longer length of stay than those who did not (P 0.009). Analysis by gender showed that perforation rates continued to be significantly higher in males undergoing CT scans (P 0.004). To examine the possibility that sicker patients were more likely to receive CT scans and also be found to have perforated appendicitis, a sensitivity analysis was performed. Patients showing perforated appendicitis on initial CT scans were excluded and the analysis was repeated. The difference in perforation rates continued to remain significant (P 0.037). ConclusionMales undergoing CT scans are significantly more likely to have perforated appendicitis. A protocol-driven rational approach to CT evaluation of suspected appendicitis may lower perforation rates, especially in males.

Interobserver Variation in the Assessment of Appendiceal Perforation

Following an appendectomy, surgeons define appendicitis, for treatment and billing purposes, into one of four categories: normal appendix, acute appendicitis, gangrenous appendicitis, and perforated appendicitis. Treatment of appendicitis is predicated upon classification at the time of visual inspection. Further, this classification often plays a role in the assessment of hospital outcomes. The currently accepted classification system is based solely upon intraoperative surgeon opinion and not objective data. Inconsistent surgeon grading of the severity of appendicitis may have implications in both management and outcomes. The aim of this study was to assess the interobserver variation among surgeons in grading of the inflammatory severity of acute appendicitis as recognized on visual findings at operation. A cross-sectional study design. 110 surgeons, and surgical residents were randomly selected. Surgeons were shown images of intraoperative appendicitis and were asked to evaluate the severity of the appendicitis (i.e., normal, inflamed, gangrenous, and perforated). Demographic information regarding the type of practice, hospital setting, and the number of encounters with patients with acute appendicitis were assessed. An Intraclass Correlation Coefficient score, represented by R, was calculated to assess interobserver reliability in grading the inflammatory severity of acute appendicitis. The two-way analysis of variance procedure for multivariate analysis was used for this calculation. The study group consisted of 100 surgeons, 62 practicing surgeons, and 48 surgical trainees. Overall, 79% of the surgeons treated predominantly adults with appendicitis, 18% treated primarily children, and 3% treated both children and adults. Hospital practices included university hospitals (47%), community hospitals (33%), children's hospitals (14%), and others (6%). Overall, there was poor agreement among surgeons in assessing the severity of appendicitis. Among all attending surgeons, the agreement of defining an image as to whether it was perforated or not was 27% (R4 = 0.27). Completion of a general surgery residency did improve the interobserver agreement, when compared with trainees. There is poor agreement among surgeons in describing the severity of appendicitis. Treatment protocols based on more accurate assessment and categorization could potentially lead to more favorable, cost-effective outcomes. Further, studies determining efficacy in the diagnosis and treatment of appendicitis should consider observer variability. Future work must attempt to define critical objective assessment points, such as visible discontinuity of the appendix or fecal soilage, to assure a better correlation of findings with prognosis.

Diagnostic value of hyperbilirubinemia as a predictive factor for appendiceal perforation in acute appendicitis

Background Appendiceal perforation in patients with acute appendicitis may cause a variety of potentially life-threatening complications. Escherichia coli endotoxin has been shown to impact physiological bile flow in vivo. This had led to the theory that hyperbilirubinemia in patients with appendicitis may have a predictive potential for the preoperative diagnosis of appendiceal perforation. The aim of this retrospective study was to investigate the diagnostic value of hyperbilirubinemia as a preoperative laboratory marker for appendiceal perforation in patients with acute appendicitis. Methods We identified 538 patients (306 female; 232 male, mean age, 35.6 y) with histologically proved acute appendicitis who underwent laparoscopic or conventional appendectomy between January 2004 and December 2007 in a surgical department of an academic teaching hospital. A retrospective multiple chart review of the medical records including laboratory values and histologic results was conducted. Results The mean bilirubin level of all patients was .9 mg/dL (±.6 SD mg/dL; range, .1–4.3 mg/dL; median, .7 mg/dL). Patients with appendiceal perforation, however, had a mean bilirubin level of 1.5 mg/dL (±.9 SD mg/dL; range, .4–4.3 mg/dL; median, 1.4 mg/dL), which was significantly higher than those with a nonperforated appendicitis ( P < .05). The specificity of hyperbilirubinemia for appendiceal perforation was .86 compared with .55 for white blood count and .35 for C-reactive protein. Sensitivity was .7 compared with .81 for white blood count and .96 for C-reactive protein. Conclusions Patients with hyperbilirubinemia and clinical symptoms of appendicitis should be identified as having a higher probability of appendiceal perforation than those with normal bilirubin levels.

Pregnant Patients Suspected of Having Acute Appendicitis: Effect of MR Imaging on Negative Laparotomy Rate and Appendiceal Perforation Rate

To investigate the effect of magnetic resonance (MR) imaging on the negative laparotomy rate (NLR) and the perforation rate (PR) in pregnant patients suspected of having acute appendicitis (AA) and to assess the need for computed tomography (CT) in this setting. The data of 148 consecutive pregnant patients (mean age, 29 years; age range, 15-42 years; mean gestational age, 20 weeks; gestational age range, 4-37 weeks) who were clinically suspected of having AA and examined with MR imaging between March 2002 and August 2007 were retrospectively analyzed in an institutional review board-approved HIPAA-compliant protocol. One hundred forty patients underwent ultrasonography (US) before MR imaging. The clinical and laboratory data and the findings of the initial US and MR image interpretations were recorded and analyzed at Student t and Fisher exact testing. The NLR and PR were calculated. Fourteen (10%) patients had AA, and perforation occurred in three (21%) of them. US results were positive for AA in five (36%) patients with proved AA. MR results were positive in all 14 patients with AA. MR results were negative in 125 of the 134 patients without AA; there were nine false-positive cases (two positive, seven inconclusive). Among the patients without AA, the normal appendix could be visualized on US images in less than 2% (two of 126) of cases and on MR images in 87% (116 of 134) of cases (P < .0001). Twenty-seven (18%) patients underwent surgical exploration, and eight of them had negative laparotomy results, yielding an NLR of 30% and a PR of 21% (three of 14 patients). Only four (3%) patients underwent CT. For pregnant patients clinically suspected of having AA, use of MR imaging yields favorable combinations of NLR and PR compared with previously reported values. The radiation exposure associated with CT examination can be avoided in most cases.

Challenges and Pitfalls of Combining Targeted Agents in Phase I Studies

Challenges and Pitfalls of Combining Targeted Agents in Phase I Studies