Usefulness of intestinal ultrasound in inflammatory bowel disease

Imaging techniques play a fundamental role in the initial diagnosis and follow-up of inflammatory bowel disease. Intestinal ultrasound has high sensitivity and specificity in patients with suspected Crohn's disease and in the detection of inflammatory activity. This technique enables the early diagnosis of intra-abdominal complications such as stenosis, fistulas, and abscesses. It has also proven useful in monitoring the response to treatment and in detecting postsurgical recurrence. Technical improvements in ultrasound scanners, technological advances such as ultrasound contrast agents and elastography, and above all increased experience have increased the role of ultrasound in the evaluation of the gastrointestinal tract. The features that make ultrasound especially attractive include its wide availability, its noninvasiveness and lack of ionizing radiation, its low cost, and its good reproducibility, which is important because it is easy to repeat the study and the study is well tolerated during follow-up. This review summarizes the role of intestinal ultrasound in the detection and follow-up of inflammatory bowel disease.

Systematic review: the use of ultrasonography, computed tomography and magnetic resonance imaging for the diagnosis, assessment of activity and abdominal complications of Crohn's disease

BACKGROUND

Cross-sectional imaging techniques, including ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI), are increasingly used for evaluation of Crohn's disease (CD). Aim  To perform an assessment of the diagnostic accuracy of cross-sectional imaging techniques for diagnosis of CD, evaluation of disease extension and activity and diagnosis of complications, and to provide recommendations for their optimal use.

METHODS

Relevant publications were identified by literature search and selected based on predefined quality parameters, including a prospective design, sample size and reference standard. A total of 68 publications were chosen.

RESULTS

Ultrasonography is an accurate technique for diagnosis of suspected CD and for evaluation of disease activity (sensitivity 0.84, specificity 0.92), is widely available and non-invasive, but its accuracy is lower for disease proximal to the terminal ileum. MRI has a high diagnostic accuracy for the diagnosis of suspected CD and for evaluation of disease extension and activity (sensitivity 0.93, specificity 0.90), and is less dependent on the examiner and disease location compared with US. CT has a similar accuracy to MRI for assessment of disease extension and activity. The three techniques have a high accuracy for identification of fistulas, abscesses and stenosis (sensitivities and specificities >0.80), although US has false positive results for abscesses. As a result of the lack of radiation, US or MRI should be preferred over CT, particularly in young patients.

CONCLUSIONS

Cross-sectional imaging techniques have a high accuracy for evaluation of suspected and established CD, reliably measure disease severity and complications; they may offer the possibility to monitor disease progression.

[Ultrasound and CT study of duodenal pathology]

The radiological evaluation of the duodenum has traditionally been based on barium transit studies; however, ultrasound (US) and computed tomography (CT) are becoming more important in the assessment of this portion of the intestine and the structures that surround it. This report describes and illustrates the CT and US findings for different entities that affect the duodenum, including diseases of the duodenum itself and those of neighboring organs that affect this portion of the small intestine. We classify the pathologies by etiology into congenital, traumatic, iatrogenic and foreign bodies, bezoars, hematologic, inflammatory and neoplastic. Moreover, we present the incidental duodenal and periduodenal findings in US and CT that radiologists should be familiar with given the widespread use of these techniques.

Pancreatic pseudotumor in Meckel diverticulum

This report describes the ultrasonic appearance of an ectopic pancreatic rest presenting as a mass within an intussusception due to an inverted Meckel diverticulum. Familiarity with the ultrasound appearance of this entity may be useful to obviate unnecessary imaging workup.

[Value of C-reactive protein level in the detection of necrosis in acute pancreatitis]

OBJECTIVES

To evaluate the utility of C-reactive protein (CRP) in the detection of necrosis in acute pancreatitis and to determine the best cut-off point for CRP used for this purpose.

MATERIAL AND METHODS

We performed a retrospective study of 157 patients with acute pancreatitis who underwent computed tomography (CT) with intravenous contrast material between 72 h and 8 days after the onset of symptoms and whose serum CRP values were determined by nephelometry 24 h or later after the onset of pain.

RESULTS

Ninety-four patients were men and 63 were women, with a mean age of 61 years (range, 15-96 years). The cause of pancreatitis was biliary lithiasis in 53.5%, alcohol in 20.4%, and idiopathic in 10.8%. Other causes were found in 15.3%. The mean (standard deviation) time elapsed between symptom onset and extraction to evaluate CRP was 3.21 (1.7) days. The patients were divided into two groups according to the results of CT: 132 patients with acute intersitial edematous pancreatitis and 25 patients with acute necrotizing pancreatitis. The mean CRP concentrations were: 322 mg/l (range, 10.7-538) in patients with acute necrotizing pancreatitis and 133 mg/l (range, 3-442) in those with acute interstitial pancreatitis; this difference was statistically significant (p < 0.001). The area under the ROC curve of CRP vs. the occurrence of necrosis was 0.862 (95% CI, 0.778, 0.946). To evaluate the presence of pancreatic necrosis a cut-off level of 200 mg/l showed a sensitivity of 88% and a specificity of 75% while a cut-off level of 279 mg/l presented a sensitivity of 72% and a specificity of 88%.

CONCLUSIONS

In acute pancreatitis, a CRP value of less than or equal to 200 mg/l obtained at 72 h of symptom onset is useful for ruling out, with a high degree of probability, the presence of necrosis. With higher values, additional investigations should be performed to determine the presence of pancreatic necrosis; nevertheless, with values higher than 279 mg/l the risk of necrosis markedly increases.

[Lymphadenomegaly in patients with chronic liver disease]

Abdominal lymphadenomegaly is a frequent ultrasonographic finding in patients with chronic liver disease. Its clinical significance is not well understood. The aim of this study was to determine the relationship between this finding and several characteristics of liver disease in 44 patients with chronic liver disease (79.5% due to hepatitis C virus). To do this, all patients underwent simultaneous liver biopsy and abdominal ultrasonography, in which the number and localization of the enlarged abdominal lymph nodes were confirmed. Viral load in patients with chronic hepatitis C virus infection was determined. No significant differences were found in serum hepatitis C RNA concentrations between patients who presented lymphadenomegaly and those who did not. However, the presence of lymphadenomegaly was associated with greater histological activity. If this finding were confirmed in studies with larger samples, the presence of ultrasonographically-detected enlarged abdominal lymph nodes in patients with chronic liver disease due to hepatitis C virus infection would indicate more severe histological lesions.

Utility of intrarenal Doppler ultrasound in the diagnosis of renal artery stenosis

PURPOSE

To determine the utility of intrarenal Doppler parameters and waveform analysis in a hypertensive population screened for renal artery stenosis (RAS).

MATERIALS AND METHODS

Sixty five patients were studied (122 kidneys) with intrarenal Doppler sonography. Doppler waveforms of three different areas from each kidney were obtained (superior, middle and inferior level). Waveform morphology, acceleration time (AT), acceleration (Ac) and resistive index (RI) were evaluated in each kidney, comparing retrospectively the Doppler findings with the angiographic results.

RESULTS

Arteriography demonstrated 33 (27.2%) renal arteries with stenosis (18 with RAS>75%). Statistically significant differences for AT and Ac were found among the patients with RAS>75% and the other groups (P<0.01). An AT>80 ms and an Ac< or =1 m/s(2) showed a sensitivity of 89% and a specificity of 99%, for the diagnosis of RAS>75%. Better results were obtained in patients less than 50 years old (100% of sensitivity and specificity). The morphologic analysis of the Doppler waveform had poor results but the detection of a waveform grade 0 had a high specificity (98%). An additional comparison of both kidneys didn't improve the results.

CONCLUSION

Intrarenal Doppler waveform analysis using quantitative measurements (AT and Ac) is an adequate technique for the diagnosis of severe RAS in previously selected patients, especially in younger patients (<50 years).

Gastrointestinal bezoars: sonographic and CT characteristics

OBJECTIVE

The purpose of this study was to assess the value of imaging studies--conventional abdominal radiographs, sonography, and CT--in the diagnosis of gastrointestinal bezoars.

METHODS AND METHODS

A review was made of the radiologic findings of 17 consecutive patients with surgically verified gastrointestinal bezoars over a period of 51 months.

RESULTS

Twelve patients had a history of previous gastric surgery. In no patient was a bezoar clinically suspected. Phytobezoars were recorded in 16 patients and a trichobezoar in only one. A total of 33 bezoars were identified at surgery. Two patients had isolated gastric bezoars, whereas 15 patients had bezoars located in the small bowel. Among the latter group, associated gastric bezoars were found in eight patients, and five patients had multiple intestinal bezoars. Abdominal radiographs revealed bezoars in three patients, sonography revealed bezoars in 15, and CT revealed bezoars in all 17. Seven patients had associated gastric bezoars revealed at CT versus only two patients with gastric bezoars revealed at sonography. CT revealed multiple intestinal bezoars in five patients whereas sonography revealed them in only two patients.

CONCLUSION

Both sonography and CT are reliable methods for diagnosing gastrointestinal bezoars. CT is more accurate, however, and exhibits a quite characteristic bezoar image; in addition, this imaging technique is able to reveal the presence of additional gastrointestinal bezoars.

Gallstone ileus: increased diagnostic sensitivity by combining plain film and ultrasound

BACKGROUND

Gallstone ileus is an uncommon cause of mechanical obstruction. Its high mortality rate can be reduced with earlier diagnosis and treatment. We wanted to determine whether ultrasound (US) performed after plain film increases the sensitivity for the preoperative diagnosis.

METHODS

We performed a 5-year retrospective analysis of radiologic and sonographic results of 23 patients who had surgery because of gallstone ileus.

RESULTS

Rigler's triad was identified by plain abdominal film in two patients (9%) and by US in 16 patients (69%). Plain abdominal film contributed to a definitive diagnosis in four cases and to a probable diagnosis in six cases (sensitivities of 17% for definitive diagnoses and 43% for definitive and probable diagnoses). US confirmed the diagnosis in six cases of probable gallstone ileus and provided the diagnosis in seven of 13 patients without suspected gallstone ileus based on plain abdominal film. The best results were obtained by combining plain film and US findings, with sensitivities of 74% for definitive diagnoses and 96% for definitive plus probable diagnoses.

CONCLUSION

The preoperative diagnosis of gallstone ileus significantly increases by combining plain film and US findings.

Hepatic and splanchnic perfusion and oxygenation after transjugular intrahepatic portosystemic shunt

OBJECTIVE

in patients with cirrhosis, transjugular intrahepatic portosystemic shunt (TIPS) decreases the pressure in the portal vein by rerouting nearly all the portal blood flow to the systemic circulation. This may lead to hypoperfusion of the liver and worsening function. Our aim was to investigate whether TIPS actually reduced hepatic and splanchnic perfusion.

METHODS

we studied 25 patients who required placement of a TIPS (20 for variceal bleeding and 5 for refractory ascites). We evaluated the clinical condition, laboratory results, blood velocity in the portal vein and hepatic artery by echo-Doppler ultrasonography, systemic hemodynamic-oxygenation status and hemodynamic-oxygenation status in the portal and suprahepatic veins before TIPS, 15 min after the procedure, and 30 days later. Hepatic and splanchnic perfusion were evaluated as the arteriovenous difference in O2 content and as the O2 extraction rates in the hepatic and splanchnic territories.

RESULTS

TIPS induced an immediate decrease in portal pressure, a significant increase in systemic hyperdynamic state, and an increase in blood flow velocity in the portal vein and hepatic artery. Thirty days after the procedure these changes persisted, although they were somewhat attenuated. Although splanchnic and liver perfusion were not changed 15 min or 30 days after TIPS, there was a slight tendency toward a decrease in liver perfusion during follow-up.

CONCLUSIONS

TIPS increased the hyperdynamic state in the systemic side. However, portal blood shunting did not change liver or splanchnic perfusion.

Appendicular involvement in perforated sigmoid disease: US and CT findings

We describe four patients in whom ultrasound (US) and/or computed tomography (CT) demonstrated a thickened appendix, secondarily enlarged due to perforated sigmoid diverticulitis (n = 2) or carcinoma (n = 2). The underlying pathology was correctly recognized in all cases. Secondary thickening of the appendix due to perforated sigmoid disease provides a potential pitfall mainly on US and may lead to an incorrect diagnosis and thus to unnecessary surgery or a wrong surgical intervention. Although US alone is enough to diagnose periappendicitis and sigmoid disease, combined use of US and CT may improve assessment of its origin and extension.

Primary epiploic appendagitis: US and CT findings

A retrospective review is presented of seven cases of epiploic appendagitis, with surgical confirmation in one case. The main clinico-analytical data and the US and CT findings are described, as well as the histopathologic features in the sole case that underwent surgical resection. We also calculated the frequency of this entity in patients undergoing emergency abdominal US on clinical suspicion of diverticulitis. In all seven cases the clinico-analytical evidence was nonspecific (localized acute abdominal pain and slight leukocytosis), mimicking in six cases the clinical presentation of sigmoid diverticulitis and in one case that of acute appendicitis. US imaging findings were characteristic: a hyperechoic mass localized under the point of maximum pain, adjacent to the anterior peritoneal wall and fixed during deep breathing. In none of the cases did color Doppler US show flow. CT findings were also typical and showed a mass with a peripheral hyperattenuated rim surrounding an area of fatty attenuation. Overall 7.1 % of patients investigated to exclude sigmoid diverticulitis finally showed findings of primary epiploic appendagitis. Primary epiploic appendagitis thus shows characteristic US and CT findings that allow its diagnosis and follow-up. This entity is much more frequent than previously reported, especially in patients referred for US to exclude sigmoid diverticulitis.

Diseases that simulate acute appendicitis on ultrasound

Ultrasound is useful in the assessment of patients with possible appendicitis. A diagnosis of appendicitis can be made in patients with persistent right lower quadrant pain when a non-compressible appendix greater than 6 mm in diameter is shown. When a normal appendix is affected by an adjacent lesion, reactive inflammation can cause secondary enlargement of the appendix. This article reviews ultrasound findings in conditions which can clinically mimic acute appendicitis. Examples of Crohn's disease, tuboovarian abscess, typhilitis, sigmoid diverticulitis, perforated sigmoid neoplasm, perforated peptic ulcer, perforated acute cholecystitis, caecal carcinoma and appendiceal tumours are included.