The management of complicated diverticulitis and the role of computed tomography

PURPOSE

Acute diverticulitis is a disease with a wide clinical spectrum, ranging from a phlegmon (stage Ia), to localized abscesses (stages Ib and II), to free perforation with purulent (stage III) or feculent peritonitis (stage IV). While there is little debate about the best treatment for mild episodes and/or very severe episodes, uncertainty persists about the optimal management for intermediate stages (Ib and II). The aim of our study was therefore to define the role of computed tomography (CT) and to analyze its impact on the management of acute diverticulitis.

METHODS

We retrospectively analyzed 511 patients (296 males, 215 females) admitted for acute diverticulitis between January 1994 and December 2003. Excluded were patients with stoma reversal only, "diverticulitis" mimicked by cancer, or significantly deficient patient records. Patients were analyzed either as a whole or subgrouped according to age (<40 yr, >40 yr). A modified Hinchey classification was used to stage the severity of acute diverticulitis.

RESULTS

In 99 patients (19.4%), an abscess was found (74 pericolic, 25 pelvic, median diameter: 4.0 cm). CT-guided drainage was performed in 16 patients, one failure requiring a two-stage operation. Whereas conservative treatment failed in 6.8% in patients without abscess or perforation, 22.2% of patients with an abscess required an urgent resection (68.2%, one-stage, 31.8%, two-stage). Recurrence rates were 13% for mild cases, as compared to 41.2% in patients with a pelvic abscess (stage II) treated conservatively with/without CT-guided drainage. Of all surgical cases, resection/primary anastomosis was achieved in 73.6% with perioperative mortality of 1.1% and leak rate was 2.1%.

CONCLUSIONS

CT evidence of a diverticular abscess has a prognostic impact as it correlates with a high risk of failure from nonoperative management regardless of the patient's age. After treatment of diverticulitis with CT evidence of an abscess, physicians should strongly consider elective surgery in order to prevent recurrent diverticulitis.

Ingested foreign bodies of the gastrointestinal tract: retrospective analysis of 542 cases

Ingested foreign bodies (FBs) present a common clinical problem. As the incidence of FBs requiring operative removal varies from 1% to 14%, it was decided to perform this study and compare the data with those from the world literature, as well as to outline an algorithm for management, including indications for surgery. We reviewed all patients with FB ingestion from 1973 to 1993. There were 542 patients with 1203 ingestions, aged 15 to 82 years. Among them, 69. 9% (n = 379) were jail inmates at the time of ingestion, 22.9% (n = 124) had a history of psychosis, and 7.2% (n = 39) were alcoholics or denture-wearing elderly subjects. Most foreign bodies passed spontaneously (75.6%; n = 410). Endoscopic removal was possible in 19. 5% (n = 106) and was not associated with any morbidity. Only 4.8% (n = 26) required surgery. Of the latter, 30.8% (n = 8) had long gastric FBs with no tendency for distal passage and were removed via gastrotomy; 15.4% (n = 4) had thin, sharp FBs, causing perforation; and 53.8% (n = 14) had FBs impacted in the ileocecal region, which were removed via appendicostomy. Conservative approach to FB ingestion is justified, although early endoscopic removal from the stomach is recommended. In cases of failure, surgical removal for gastric FBs longer than 7.0 cm is wise. Thin, sharp FBs require a high index of suspicion because they carry a higher risk for perforation. The ileocecal region is the most common site of impaction. Removal of the FB via appendicostomy is the safest option and should not be delayed more than 48 hours.

Introduction of appendiceal CT: impact on negative appendectomy and appendiceal perforation rates

OBJECTIVE To evaluate the impact of appendiceal computed tomography (CT) availability on negative appendectomy and appendiceal perforation rates.

SUMMARY BACKGROUND DATA

Appendiceal CT is 98% accurate. However, its impact on negative appendectomy and appendiceal perforation rates has not been reported.

METHODS

The authors reviewed the medical records of 493 consecutive patients who underwent appendectomy between 1992 and 1995, 209 consecutive patients who underwent appendectomy in 1997 (59% of whom had appendiceal CT), and 206 patients who underwent appendiceal CT in 1997 without subsequent appendectomy.

RESULTS

Before appendiceal CT, 98/493 patients (20%) taken to surgery had a normal appendix. After CT availability, 15/209 patients (7%) taken to surgery had a normal appendix; 7 patients did not have CT, 5 patients had surgery despite a negative CT, and 3 patients had a false-positive CT. Negative appendectomy rates were lowered overall (20% to 7%), in men (11% to 5%), in women (35% to 11%), in boys (10% to 5%), and in girls (18% to 12%). Appendiceal perforation rates dropped from 22% to 14% after CT availability. CT excluded appendicitis in 206 patients in 1997 who avoided appendectomy and identified alternative diagnoses in 105 of these patients (51%).

CONCLUSION

The availability of appendiceal CT coincided with a drop in the negative appendectomy rate from 20% to 7% in all patients, and to only 3% in patients with a positive CT. Perforation rates decreased from 22% to 14%. Appendiceal CT can be advocated in nearly all female and many male patients.

Impact of necrotizing enterocolitis on length of stay and hospital charges in very low birth weight infants

OBJECTIVE

To determine the impact of necrotizing enterocolitis (NEC) on length of stay and hospital charges.

DESIGN

Case-control study.

SETTING

Two neonatal intensive care units in an academic medical center.

PATIENTS

Infants born in 1992--1994 with birth weight <1500 g, matched by gestational age, hospital, and month of birth. MEASUREMENTS AND MAIN RESULTS. We performed odds ratio and t testing. As with previous studies, there was no single factor that increased the risk for developing NEC. However, the diagnosis of NEC increased the risk for death, infection, and the need for central line placement. Infants with surgical NEC had lengths of stay that exceeded those of controls by 60 days, whereas lengths of stay among infants with medical NEC exceeded those of controls by 22 days. Based on length of stay, the estimated total hospital charges for infants with surgical NEC averaged $186 200 in excess of those for controls and $73 700 more for infants with medical NEC. The yearly additional hospital charges for NEC were $6.5 million or $216 666 per survivor.

CONCLUSIONS

A diagnosis of NEC in the very low birth weight infant imposes a significant additional financial burden to the individual patient as well as the neonatal community as a whole. This expense justifies additional research into preventive measures and potentially costly therapies aimed at reducing the incidence of NEC. These data also provide an estimated cost to compare the cost effectiveness of new preventive measures for NEC.

Prospective comparison of diagnostic peritoneal lavage, computed tomographic scanning, and ultrasonography for the diagnosis of blunt abdominal trauma

From January through December 1990, a prospective study comparing the accuracy of diagnostic peritoneal lavage (DPL), abdominal computed tomographic (CT) scanning, and abdominal ultrasonographic (US) scanning was carried out. Patients with stable vital signs following their initial resuscitation coupled with equivocal physical examination findings received both CT and US scanning. A DPL was then done. If any of these three examinations produced positive findings, a laparotomy was done and the surgical findings were compared with the results of the diagnostic studies. Fifty-five patients were studied (44 men, 11 women), with a mean age of 43 years and a mean ISS of 18.5 +/- 10.5. The sensitivity, specificity, and accuracy were 100%, 84.2%, and 94.5% for DPL, 97.2%, 94.7%, and 96.4% for CT scanning, and 91.7%, 94.7%, and 92.7% for US scanning. Problems do exist in identifying isolated small intestinal perforations with ultrasonography. Since more and more trauma centers are using ultrasonography in the emergency department as a screening method in the management of patients with blunt abdominal trauma, it is important to avoid overestimating its capability. Frequent re-evaluation of the patient's condition, repeat ultrasonographic scans, diagnostic peritoneal lavage, and CT scanning are complementary and important in the diagnosis of blunt abdominal trauma.

Imaging for suspected appendicitis: negative appendectomy and perforation rates

PURPOSE

To determine which patients suspected of having acute appendicitis benefit from preoperative imaging.

MATERIALS AND METHODS

The medical records of 462 consecutive patients who underwent appendectomy for clinically suspected acute appendicitis and underwent preoperative evaluation at our institution were retrospectively reviewed. Patients were divided into four groups: women (n = 166), girls (n = 46), men (n = 178), and boys (n = 72). Preoperative computed tomography (CT) or ultrasonography (US), requested by the referring clinician, was performed in 313 of the 462 patients. Unnecessary, or negative, appendectomy and perforation rates were calculated for each group for preoperative evaluation with CT, with US, and with neither CT nor US. In addition, the sensitivity and positive predictive value of CT and US were calculated for diagnosing appendicitis.

RESULTS

In women, the negative appendectomy rate was significantly lower for those who underwent preoperative CT (7% [six of 85 patients], P =.005) or US (8% [four of 49 patients], P =.019), as compared with 28% [nine of 32 patients] for those who underwent no preoperative imaging (P >.35 for all groups). The negative appendectomy rates for girls, men, and boys were not significantly affected by preoperative imaging. The sensitivity of CT and US for diagnosing acute appendicitis exceeded 93% and 77%, respectively, in all groups. The positive predictive values for both CT and US were greater than 92% in all groups.

CONCLUSION

Women suspected of having appendicitis benefit the most from preoperative CT or US, with a statistically significantly lower negative appendectomy rate than women who undergo no preoperative imaging. Therefore, we propose that preoperative imaging be considered part of the routine evaluation of women suspected of having acute appendicitis.

Randomised controlled trial of ultrasonography in diagnosis of acute appendicitis, incorporating the Alvarado score

OBJECTIVES

To determine whether diagnosis by graded compression ultrasonography improves clinical outcomes for patients with suspected appendicitis.

DESIGN

A randomised controlled trial comparing clinical diagnosis (control) with a diagnostic protocol incorporating ultrasonography and the Alvarado score (intervention group).

SETTING

Single tertiary referral centre.

PARTICIPANTS

302 patients (age 5-82 years) referred to the surgical service with suspected appendicitis. 160 patients were randomised to the intervention group, of whom 129 underwent ultrasonography. Ultrasonography was omitted for patients with extreme Alvarado scores (1-3, 9, or 10) unless requested by the admitting surgical team.

MAIN OUTCOME MEASURES

Time to operation, duration of hospital stay, and adverse outcomes, including non-therapeutic operations and delayed treatment in association with perforation.

RESULTS

Sensitivity and specificity of ultrasonography were measured at 94. 7% and 88.9%, respectively. Patients in the intervention group who underwent therapeutic operation had a significantly shorter mean time to operation than patients in the control group (7.0 v 10.2 hours, P=0.016). There were no differences between groups in mean duration of hospital stay (53.4 v 54.5 hours, P=0.84), proportion of patients undergoing a non-therapeutic operation (9% v 11%, P=0.59) or delayed treatment in association with perforation (3% v 1%, P=0.45).

CONCLUSION

Graded compression ultrasonography is an accurate procedure that leads to the prompt diagnosis and early treatment of many cases of appendicitis, although it does not prevent adverse outcomes or reduce length of hospital stay.

Diagnosis of acute appendicitis in pregnant women: value of sonography

OBJECTIVE

The diagnosis of acute appendicitis in pregnant women often is difficult to make on the basis of clinical findings, and radiologic examination is limited because of the potentially hazardous effects of radiation. This study was done to assess the value of sonography in the diagnosis of acute appendicitis in pregnant women.

SUBJECTS AND METHODS

We obtained sonograms in 45 pregnant women with clinically suspected acute appendicitis. Our sonographic technique included graded-compression scanning. The left lateral decubitus position was used in the third trimester of gestation. The sonographic criterion for the diagnosis of acute appendicitis was visualization of an incompressible appendix with a maximal diameter greater than 7 mm. We correlated the sonographic findings with the surgical findings in 22 cases and with the results of clinical follow-up in 23 cases.

RESULTS

Sonography could not be used to make the diagnosis in three (7%) of 45 patients because the size of the gravid uterus prevented use of the graded-compression technique. These three patients were in the third trimester of pregnancy (greater than 35 weeks' gestation). Sonographic findings were used as a basis for diagnosis in 42 cases. Acute appendicitis was diagnosed on the basis of sonograms in 16 patients, and in all but one of these patients, acute appendicitis was confirmed by surgical and pathologic findings. In the 42 cases in which the imaging findings indicated the diagnosis, the overall sensitivity of sonography was 100%, the specificity was 96%, and the accuracy was 98%.

CONCLUSION

Our experience suggests that graded-compression sonography is a valuable procedure for detecting acute appendicitis in pregnant women despite technical difficulty in performing it during the third trimester of pregnancy.

The efficacy of nonoperative management of acute complicated diverticulitis

BACKGROUND

The surgical management of acute complicated diverticulitis has evolved to avoid emergency surgery in favor of elective resection. The optimal manner to accomplish this goal remains debatable.

OBJECTIVE

The purpose of this study was to examine the efficacy of nonoperative management of acute diverticulitis with abscess or perforation.

DESIGN

A retrospective review was performed of an institutional review board-approved database of patients admitted with a diagnosis of acute complicated diverticulitis from 1995 to 2008. Patient demographics, disease manifestation, management, and outcomes were collected.

SETTINGS

This study was conducted at a tertiary care hospital/referral center.

PATIENTS

Patients were included who presented with complicated diverticulitis defined as having an associated abscess or free air diagnosed by CT scan.

MAIN OUTCOME MEASURES

Primary end points were the success of nonoperative management and need for surgery during the initial admission.

RESULTS

One hundred thirty-six patients were identified with perforated diverticulitis: 19 had localized free air, 45 had abscess <4 cm or distant free air measuring <2 cm, 66 had abscess >4 cm or distant free air >2 cm, and 6 had distant free air with free fluid. Thirty-eight patients (28%) required percutaneous abscess drains and 37 (27%) required parenteral nutrition. Only 5 patients (3.7%) required urgent surgery at the time of admission, and 7 (5%) required urgent surgery for failed nonoperative management. Thus, the overall success rate of nonoperative management was 91%. One hundred twenty-four of 131 (95%) patients were treated with nonoperative management successfully. Twenty-five of 27 (92.5%) patients with free air remote from the perforation site were successfully treated nonoperatively.

CONCLUSIONS

Nonoperative management of acute complicated diverticulitis is highly effective. For patients with free air remote from the site of perforation, nonoperative management is able to convert an emergent situation into an elective one in 93% of cases. The decision to attempt nonoperative therapy must be made based on the patient's physiologic state and associated comorbidities.

CT in the preoperative diagnosis of fish bone perforation of the gastrointestinal tract

OBJECTIVE

Foreign body perforation of the gastrointestinal (GI) tract has diverse clinical manifestations, and the correct preoperative diagnosis is seldom made. We report our experience with the use of CT in the preoperative diagnosis of fish bone perforation of the GI tract in seven patients. To our knowledge, this series is the largest to date addressing the role of CT in the diagnosis of fish bone perforation.

CONCLUSION

Clinical presentation and radiography are unreliable in the preoperative diagnosis of fish bone perforation of the GI tract. This limitation can be overcome with the use of CT, which is accurate in showing the offending fish bone. The accuracy of CT is limited by observer dependence. A high index of suspicion should always be maintained for the correct diagnosis to be made.

Accuracy of MDCT in predicting site of gastrointestinal tract perforation

OBJECTIVE

The purpose of this study was to prospectively evaluate the accuracy of MDCT for preoperative determination of the site of surgically proven gastrointestinal tract perforations and to determine the most predictive findings in this diagnosis.

SUBJECTS AND METHODS

We prospectively studied 85 consecutive patients with extraluminal air on MDCT who had surgically proven gastrointestinal tract perforations. All patients underwent surgery within 12 hours after MDCT was performed. Two experienced radiologists, blinded to the surgical diagnosis, reached a consensus prediction of the site of the perforation using the following eight MDCT findings: concentration of extraluminal air bubbles adjacent to the bowel wall, free air in supramesocolic or inframesocolic compartments, extraluminal air in both abdomen and pelvis, focal defect in the bowel wall, segmental bowel-wall thickening, perivisceral fat stranding, abscess, and extraluminal fluid. MDCT imaging results were compared with surgical and pathologic findings. Logistic regression analyses were performed to assess the significance of the different radiologic criteria.

RESULTS

Analysis of MDCT images was predictive of the site of gastrointestinal tract perforation in 73 (86%) of 85 patients. Logistic regression showed that concentration of extraluminal air bubbles (p < 0.001), segmental bowel wall thickening (p < 0.001), and focal defect of the bowel wall (p = 0.007) were strong predictors of the site of bowel perforation.

CONCLUSION

MDCT is highly accurate for predicting the site of gastrointestinal tract perforations. Three of eight CT findings significantly correlate with surgical diagnosis.

The accuracy of computed tomography in the diagnosis of blunt small-bowel perforation

BACKGROUND

Computed tomography (CT) is commonly used to evaluate patients with possible blunt intra-abdominal injury. One of its reported weaknesses is failure to demonstrate intestinal trauma. However, CT accuracy in identifying blunt small-bowel perforation has not been adequately assessed.

PATIENTS AND METHODS

We tracked 883 consecutive stable trauma victims who had abdominal CT because of equivocal physical findings. Initial "wet reading" results were compared with laparotomy findings and patient outcome.

RESULTS

Small-bowel perforation occurred in 26 patients (3%). Twenty-four had CT abnormalities suggesting the injury. Twelve had CT findings considered diagnostic: contrast extravasation (n = 5) and/or extraluminal air (n = 11). One additional patient was thought to have free air on CT, but had no intestinal injury at laparotomy. Another 12 patients had CT scans that were non-diagnostic but suggestive: free fluid without solid organ injury (n = 10), or small-bowel thickening (n = 4) or dilatation (n = 3). Two patients with small-bowel injuries had normal CT scans. Of 857 patients without small-bowel disruption, 802 had normal abdominal CT scans, and 55 had 67 CT findings suggesting intestinal injury. Thus, CT diagnosed small-bowel perforation with a sensitivity of 92%, a specificity of 94%, and negative and positive predictive accuracies of 100% and 30%, respectively. The test had an overall accuracy (validity) of 94%.

CONCLUSIONS

Blunt small-bowel injury is uncommon. When it is present, abdominal CT is usually abnormal. CT findings in intestinal perforation can be subtle and nonspecific. Any unexplained abnormality on CT after blunt abdominal trauma may signal the presence of intestinal perforation and warrants close clinical observation or further diagnostic tests.

Acute appendicitis: MR imaging and sonographic correlation

OBJECTIVE

Acute appendicitis is the most common indication for emergency abdominal surgery. To our knowledge, MR imaging has not been compared with sonography for revealing acute appendicitis. Our aim was to assess and compare the accuracy, advantages, and limitations of MR imaging and sonography in revealing appendicitis.

SUBJECTS AND METHODS

The study included 60 consecutive patients suspected of having appendicitis who underwent abdominal sonography and MR imaging. Fat-suppressed T2-weighted fast spin-echo and gadolinium-enhanced fat-suppressed T1-weighted spin-echo axial and coronal images were obtained. The initial MR imaging and sonographic studies were later correlated with the surgical-pathologic findings, follow-up evaluations, and diagnosis at the time of discharge.

RESULTS

Surgical, histopathologic, and follow-up results revealed that 34 patients had appendicitis. Of the 26 patients without appendicitis, 15 with symptoms of acute appendicitis had no pathologic diagnoses and the remaining 11 had another diagnosis. Comparison of the sensitivity, accuracy, and negative predictive values for MR imaging and sonography was found to be statistically significant (p < .05, chi-square test), indicating that MR imaging was superior to sonography in revealing appendicitis. We found no statistical difference in specificity and positive predictive value for MR imaging and sonography.

CONCLUSION

Despite some disadvantages, we found MR imaging to be superior to sonography in revealing suspected acute appendicitis. MR imaging can be used after suboptimal or nondiagnostic sonography in cases of suspected acute appendicitis.

Spiral CT of colon cancer: imaging features and role in management

Colorectal cancer is a common malignancy that results in significant morbidity and mortality. Abdominal computed tomography (CT) is valuable in planning surgery for colon cancer because it can demonstrate regional extension of tumor as well as adenopathy and distant metastases. At CT, colorectal cancer typically appears as a discrete soft-tissue mass that narrows the colonic lumen. Colorectal cancer can also manifest as focal colonic wall thickening and luminal narrowing. Complications of primary colonic malignancies such as obstruction, perforation, and fistula can be readily visualized with CT. At CT, local extension of tumor appears as an extracolic mass or simply as thickening and infiltration of pericolic fat. Extracolic spread is also suggested by loss of fat planes between the colon and adjacent organs. The liver is the predominant organ to be involved with metastases from colorectal cancer. At CT, hepatic metastases usually appear as hypoattenuating masses, which are best visualized during the portal venous phase of liver enhancement. Other common sites of metastases from colon cancer include the lungs, adrenal glands, and bones. Use of CT is critical for identifying recurrences, evaluating anatomic relationships, documenting "normal" postoperative anatomy, and confirming the absence of new lesions during and after therapy.

Sonography of acute appendicitis in children: 7 years experience

OBJECTIVE

The objective of this prospective study was to determine the accuracy in diagnosing appendicitis in children by using high-resolution graded compression sonography.

MATERIALS AND METHODS

During a 7-year period, 3859 children (mean age 9.9 years) with clinically suspected appendicitis were evaluated by sonography with the graded compression technique. The ultrasound results were correlated with the intraoperative and histopathological findings or clinical outcome.

RESULTS

High-resolution sonography was performed in 3859 children. Of the 610 patients who underwent a laparotomy, 494 had histologically proven acute or perforated appendicitis (prevalence 13%). In these children, sensitivity, specificity and overall accuracy of sonography were 90%, 97% and 96%, respectively. The reasons for false-negative and false-positive results are discussed.

CONCLUSION

Although the use of ultrasound to diagnose acute appendicitis in children has excellent results, the decision for surgery remains a clinical one because of the continuing false-negative and false-positive results from sonography.

Correlation of sonographic findings and outcome in necrotizing enterocolitis

BACKGROUND

There is little in the literature regarding the use of gray-scale and Doppler sonography of the bowel in necrotizing enterocolitis (NEC) and how findings depicted by this modality might assist in predicting outcome and influence management.

OBJECTIVE

To correlate sonographic findings with outcome in NEC.

MATERIALS AND METHODS

This was a retrospective analysis of clinical and abdominal ultrasonography (AUS) findings in NEC from January 2003 to December 2005. AUS findings were evaluated for portal venous gas, free gas, peritoneal fluid, bowel wall thickness, echogenicity, perfusion and intramural gas. Patients were categorized into two groups, according to their outcome.

RESULTS

A total of 40 infants were identified who had AUS for NEC prior to any surgical intervention. Group A comprised 18 neonates treated medically and recovered fully, and group B comprised 22 neonates who required surgery or died. Free gas (six patients) and focal fluid collections (three patients) were only found in group B. Increased bowel wall echogenicity, absent bowel perfusion, portal venous gas, bowel wall thinning, bowel wall thickening, free fluid with echoes and intramural gas were seen in both groups, but more frequently in group B. Anechoic free fluid was seen more frequently in group A. Increased bowel perfusion was seen equally in both groups.

CONCLUSION

An adverse outcome was associated with the sonographic findings of free gas, focal fluid collections or three or more of the following: increased bowel wall echogenicity, absent bowel perfusion, portal venous gas, bowel wall thinning, bowel wall thickening, free fluid with echoes and intramural gas. Sonographic findings are useful in predicting outcome and therefore might help guide management.

Spiral CT and multidetector-row CT diagnosis of perforation of the small intestine caused by ingested foreign bodies

The aim of this retrospective study was to emphasize the performances of spiral CT (HCT) and multidetector-row CT (MDCT) as very effective imaging modalities for the diagnosis of intestinal perforations caused by calcified alimentary foreign bodies. Eight sites of perforations of the ileum by ingested foreign bodies were found in seven patients--one patient presenting with two separate sites of perforation. The diagnosis was successfully made by HCT in four patients and MDCT in the remaining three. Involuntarily and generally unconsciously ingested chicken and fish bones were the implicated calcified foreign bodies. The acute clinical presentations were nonspecific, mimicking more common acute abdominal conditions. A thickened intestinal segment (7/8 sites) with localized pneumoperitoneum (4/8 sites), surrounded by fatty infiltration (4/8 sites) and associated with already present or developing obstruction or sub-obstruction (5/7 patients) were the most common CT signs, but the definite diagnosis was clearly made by the identification of the calcified foreign bodies (7/7 patients). In each patient, this identification was only possible thanks to the scrupulous analysis of very thin overlapping reconstructions obtained not only in the perforation sites (6/8 sites), but also through the entire abdomen (2/8 sites). Our report emphasizes the high performances of CTA and MDCT in identifying intestinal perforation caused by calcified alimentary foreign bodies. Moreover, the high specificity of the CT diagnosis made it possible to avoid surgerical exploration in three patients.

Unusual abdominal complications of ventriculo-peritoneal shunts

Placement of ventriculo-peritoneal (VP) shunts is an established procedure for treatment of hydrocephalus. With increasing longevity following successful treatment, complications are becoming more common. The authors reviewed 350 VP shunts in 242 patients and found five uncommon complications relating to the peritoneal end of the catheter: (a) cerebrospinal fluid (CSF) pseudocyst of the lesser sac, (b) subphrenic CSF loculation, (c) bowel perforation and formation of a CSF-enteric fistula, (d) intrathoracic migration of the tip of the shunt, and (e) intractable CSF ascites.

Manifestations of Crohn disease at US

Crohn disease is a chronic inflammatory disorder of the intestines that is characterized by multiple episodes of exacerbation and remission. Although barium studies and endoscopy remain the most valuable tools for assessment of mucosal and luminal changes, sonography has proved to be a safe and noninvasive modality for characterization of mural and perienteric changes. Ultrasonography (US) can accurately demonstrate the classic features of Crohn disease as well as the complications frequently associated with the disease. The addition of color Doppler imaging may allow differentiation of chronic from active bowel wall thickening. In expert hands, US appears to be a sensitive modality for preliminary investigation of patients with symptomatic Crohn disease. US can also be used to assess the response to treatment and to detect postoperative recurrence. Finally, US enables accurate selection of patients in whom the possibility of surgery or percutaneous intervention would justify other means of investigation, particularly computed tomography.

Duodenal injuries caused by blunt abdominal trauma: value of CT in differentiating perforation from hematoma

OBJECTIVE

Traumatic duodenal perforation requires emergent surgery, whereas duodenal hematoma can often be treated nonsurgically. We assessed the CT findings in patients with blunt duodenal trauma to determine if CT can be used to differentiate these two duodenal injuries.

MATERIAL AND METHODS

Seven consecutive patients with blunt duodenal trauma (three with perforation, four with hematoma) who underwent CT as part of their initial diagnostic evaluation were included in the study. All three perforations and one of four hematomas were surgically proved. Diagnoses of duodenal hematoma in the other three patients were based on typical features on upper gastrointestinal studies and complete resolution of clinical findings after conservative treatment. The CT scans were retrospectively reviewed without knowledge of the specific type of duodenal injury, and the findings were correlated with the results of the gastrointestinal studies and surgical findings.

RESULTS

CT showed extraluminal gas or extravasated oral contrast material or both in the right anterior pararenal space in all three patients with duodenal perforation and in none of the patients with duodenal hematoma. Thickening of the duodenal wall and fluid in the right anterior pararenal space were seen in both groups of patients.

CONCLUSION

Although the number of patients in the study was small, the results suggest that CT may be useful in differentiating duodenal perforation from hematoma without perforation. Extraluminal gas or extravasated oral contrast material or both were seen in the right anterior pararenal space in all three patients who had perforation and in none of the patients who had hematoma alone.

Perforated versus nonperforated acute appendicitis: accuracy of multidetector CT detection

PURPOSE

To retrospectively evaluate the accuracy of multidetector computed tomography (CT) in the diagnosis of perforated acute appendicitis by using surgery and pathologic examination combined as the reference standard.

MATERIALS AND METHODS

The study was institutional review board approved and HIPAA compliant. Informed patient consent was waived. The authors retrospectively identified 244 patients (150 male, 94 female; mean age, 32.8 years; age range, 4-83 years) with pathologically proved acute appendicitis who underwent abdominopelvic multidetector CT. Two radiologists reviewed in consensus the multidetector CT images obtained in all patients for various findings that may be associated with appendiceal perforation. For continuous variables, a comparison of means between the perforated and nonperforated groups was performed by using the Wilcoxon rank sum test. For categorical variables, the sensitivity and specificity of each CT finding for the diagnosis of perforated appendicitis were determined.

RESULTS

The CT findings of abscess (99%), extraluminal gas (98%), and ileus (93%) had the highest specificities for appendiceal perforation; however, the sensitivities of these findings were low: 34%, 35%, and 53%, respectively. The appendix was larger in patients with perforated appendicitis: The mean diameter was 15.1 mm compared with a mean diameter of 11.7 mm in patients with nonperforated appendicitis (P < .001). Appendicolith, free fluid, enlarged abdominal lymph nodes, and enhancement defect in the appendiceal wall were neither highly sensitive nor highly specific for the detection of perforation.

CONCLUSION

Although certain multidetector CT findings are very specific for the diagnosis of perforated appendicitis, overall multidetector CT sensitivity is poor. Unless abscess or extraluminal gas is present, multidetector CT cannot enable the diagnosis of perforation.

Effect of an imaging protocol on clinical outcomes among pediatric patients with appendicitis

OBJECTIVE

In 1998, we implemented a clinical imaging protocol in which children with suspected appendicitis underwent ultrasonography (US) followed by computed tomography (CT). We sought to determine the impact of the US-CT protocol on changes in perforation and negative appendectomy rates.

METHODS

Children with unequivocal presentations for appendicitis went to the operating room without entering the imaging protocol. Using a modified time series design, we analyzed a prospective and retrospective cohort of consecutive patients who were admitted from the emergency department for suspected appendicitis. The perforation and negative appendectomy rates were computed for the periods before and after implementation of the imaging protocol and adjustment for time trends was made.

RESULTS

A total of 1338 children were identified. Eight hundred ten (60.5%) children had equivocal clinical findings. A total of 920 patients were admitted for suspected appendicitis before the protocol was implemented; 526 (57.2%) of the 920 children had appendicitis, and 186 (35.4%) of them had perforation. A total of 91 (14.7%) of 617 had negative appendectomies. After the protocol was implemented, 418 patients were admitted for suspected appendicitis; 328 (78.5%) had appendicitis with 51 (15.5%) perforated. There were 14 (4.1%) of 342 cases of negative appendectomies. After implementation of the imaging protocol, the perforation rate decreased from 35.4% to 15.5%, and the negative appendectomy rate decreased from 14.7% to 4.1%. After secular time trends were adjusted for, the imaging protocol continued to have a strong association with a reduction in perforation rate and negative appendectomy rate.

CONCLUSION

The implementation of an imaging protocol using US and CT resulted in a marked decrease in the perforation and negative appendectomy rates in children with suspected appendicitis.

Ultrasonography in the management of blunt abdominal and thoracic trauma

OBJECTIVE

To assess the sensitivity, specificity, and predictive value of ultrasonography in patients with blunt abdominal or thoracic trauma in regard to the indication for immediate operation, delayed abdominal exploration, or conservative treatment.

DESIGN

A retrospective study was conducted after consecutive sampling of 1151 patients in a nonrandomized control trial.

SETTING

The study was conducted at the University Hospital of Innsbruck (Austria), which serves as a general community hospital and a major primary care and referral center.

PATIENTS

All patients with blunt abdominal or thoracic trauma with or without polytraumatization were eligible for the study; a total of 1151 patients were observed from 1980 to 1990. According to the ultrasonographic findings, patients were divided into three groups: immediate operation, primary conservative treatment, and conservative treatment (normal ultrasonographic findings). Ultrasonography was repeated when the clinical findings or laboratory test results showed the development of intra-abdominal hemorrhage or signs of organ laceration.

INTERVENTION

Ultrasonography in the emergency department or intensive care unit.

MAIN OUTCOME MEASURES

Conservative or operative treatment based on ultrasonographic and clinical findings.

RESULTS

Ultrasonography showed a sensitivity of 99%, a specificity of 98%, a positive predictive value of 0.97, and a negative predictive value of 0.99 in regard to the indication for surgery in cases of blunt abdominal or thoracic trauma. Ultrasonography is not reliable in patients with intestinal perforation and large retroperitoneal hematomas.

CONCLUSION

Ultrasonography saves time and money, can be performed in the emergency department, shows high sensitivity and specificity, and is the method of first choice in the evaluation of blunt trauma.

Diagnostic accuracy of focused appendiceal CT in clinically equivocal cases of acute appendicitis

PURPOSE

To determine the diagnostic accuracy of modified focused appendiceal computed tomography (CT) to exclude or confirm appendicitis in patients who presented with equivocal symptoms and signs of appendicitis.

MATERIALS AND METHODS

One hundred patients (age range, 14-81 years; mean age, 30.6 years) with equivocal symptoms and signs of acute appendicitis were included in this prospective study. Patients were given 30 mL of diatrizoate meglumine and diatrizoate sodium and 60 mL of sorbitol mixed in 1 L of water orally over 1 hour. CT was performed 1.5 hours after the commencement of oral contrast material administration. The criteria used for the diagnosis of appendicitis were (a) appendix greater than 6 mm in maximum diameter, (b) no contrast material in the appendiceal lumen, and (c) inflammatory changes in the periappendiceal fat. CT results were compared with histopathologic findings at appendectomy. Patients with negative CT findings were followed up by telephone or clinically.

RESULTS

Of 100 cases, 30 were positive at CT and 70 were negative. There were 28 true-positive cases; two false-positive cases, one cecal diverticulitis and one pelvic peritonitis with periappendicitis; and two false-negative cases, one perforated appendix and one mucosal and submucosal inflammation of the appendix but no transmural inflammation. Sensitivity was 93%, specificity was 97%, and accuracy was 96%.

CONCLUSION

Focused appendiceal CT in which oral contrast material is used alone yields high levels of accuracy in clinically equivocal cases of acute appendicitis.

Gastrointestinal tract perforation: CT diagnosis of presence, site, and cause

Gastrointestinal tract perforation is an emergent condition that requires prompt surgery. Diagnosis largely depends on imaging examinations, and correct diagnosis of the presence, level, and cause of perforation is essential for appropriate management and surgical planning. Plain radiography remains the first imaging study and may be followed by intraluminal contrast examination; however, the high clinical efficacy of computed tomographic examination in this field has been well recognized. The advent of spiral and multidetector-row computed tomographic scanners has enabled examination of the entire abdomen in a single breath-hold by using thin-slice sections that allow precise assessment of pathology in the alimentary tract. Extraluminal air that is too small to be detected by conventional radiography can be demonstrated by computed tomography. Indirect findings of bowel perforation such as phlegmon, abscess, peritoneal fluid, or an extraluminal foreign body can also be demonstrated. Gastrointestinal mural pathology and associated adjacent inflammation are precisely assessed with thin-section images and multiplanar reformations that aid in the assessment of the site and cause of perforation.