Dynamic cholecystosonography of the contracted gallbladder: the double-arc-shadow sign

The significance of the wall echo shadow triad on ultrasonography: a case series

Background

The wall echo shadow (WES) triad, also known as the double-arc-shadow sign consists of a well-defined near wall, echos from stones immediately beneath the wall, and posterior shadowing caused by strong echoes from stones in the gallbladder fossa. It has been used for over 20 years as a nonspecific finding suggestive of a gallbladder lumen filled with either multiple stones or one large stone (Miller et al. J Emerg Med 30(1):69–74, 2006; Blaivas et al. Acad Emerg Med 10(6):1020–1023, 1999; Raptopoulos et al. AJR Am J Roentgenol 138(2):275–278, 1982). In the past, the WES triad has been correlated with underlying chronic cholecystitis. However, there are no studies that compare clinical findings to a gold standard such as surgical pathology.

Case reports

Three cases of the WES triad were reviewed at New York Medical Hospital of Queens over a 16-month period.

Upper abdominal ultrasound in the critically ill

Intraabdominal pathology, either primary or secondary, may frequently be found in critically ill patients. Without early diagnosis and treatment, the patient's condition may deteriorate and even progress to death. In this article, we provide a current review of the literature regarding liver, biliary, pancreatic, and splenic problems in critically ill patients and describe common ultrasound findings, including the appearance of free intraperitoneal air. According to the liver surface, edge, echotexture, and echogenicity, either diffuse liver diseases or focal liver diseases can be detected on ultrasound. By scanning the biliary tree and gallbladder, many right upper quadrant diseases can be diagnosed. The role of ultrasound for acute pancreatic pathology is to identify any lesions and to evaluate the severity of the diseases. Similarly, the spleen can be evaluated for relevant pathology in the critical care setting.

Agenesis of the gallbladder: A dangerously misdiagnosed malformation

Isolated agenesis of the gallbladder is a rare anomaly, often asymptomatic. However, one patient out of four presented with right upper abdominal pain, nausea, and fatty food intolerance. The condition is frequently mistaken with an excluded or sclero-atrophic gallbladder, regardless of the imaging modality used. Consequently, AG often leads to unnecessary and potentially dangerous laparoscopic surgery as described in a few case reports over the last 10 years. The aim of this study is to clarify the diagnostic and therapeutic approach of this unusual pathology. Two cases seen in our institutions were retrospectively reviewed, together with a review of the American and European literature. During laparoscopy, the absence of normal anatomical structures and the impossibility of pulling on the gallbladder to expose and dissect the triangle of Callot increases the risk of iatrogenic injury to biliary or portal structures. Depending on the experiment of the surgeon in laparoscopic procedure, this has to be taken into account to decide a conversion to laparotomy. A high index of suspicion is necessary when interpreting the radiological images. In case of doubt, a MRI-cholangiography is mandatory. Because of possible inherited transmission, relatives with a history of biliary symptoms should be investigated.

Acute cholecystitis: radiological management

Acute cholecystitis is a common condition which may be difficult to diagnose with confidence on clinical grounds alone. A large number of techniques are now available for imaging the gall bladder but, in practice, ultrasonography and cholescintigraphy are of greatest value. The former is cheap, readily available and features such as the presence of gall stones, gall bladder wall inflammation and a positive sonographic Murphy sign strongly suggest the diagnosis of acute cholecystitis. In addition to its diagnostic uses, ultrasonographically guided percutaneous cholecystostomy provides an alternative and sometimes life-saving form of treatment in those patients who are unfit for surgery. Cholescintigraphy is a highly accurate, non-invasive method for assessing patency of the cystic duct but is not always available in the emergency situation and takes longer to perform than an ultrasound examination. Acute cholecystitis, however, has many manifestations and may be calculous or acalculous, be associated with a patent or obstructed cystic duct, and may be complicated or uncomplicated. Imagining modalities other than those mentioned above may be useful in certain circumstances and this chapter aims to present the advantages and disadvantages of each technique in order to provide guidance for the clinician caring for a patient with suspected acute cholecystitis.

Clinical significance of ultrasonographically detected coincidental gallstones

The clinical profiles of 139 patients with gallstones found coincidentally during ultrasonography were reviewed and the patients followed prospectively for five years. Indications for ultrasonography included follow-up of abdominal malignancy (33%), evaluation of abdominal aortic aneurysm or other arteriosclerotic vascular disease (22%), renal insufficiency (12%), and lower abdominal pain (7%). At the time of gallstone detection, 14 patients (10%) had symptoms attributable to cholelithiasis. Over the next five years, only 15 patients (11%) developed episodes resembling biliary pain. Nine patients underwent cholecystectomy during this period. Three of the cholecystectomies were incidental to other abdominal procedures. Two cholecystectomies were performed as emergencies for gallstone complications with no perioperative mortality. Interestingly, 54 patients (40%) with coincidental gallstones died during the follow-up period. All the deaths were unrelated to gallstones. These data indicate that ultrasonographically detected coincidental gallstones rarely have clinical significance, leading strong support to the expectant management of most patients with purely coincidental gallstones.

Preferred imaging techniques for the diagnosis of cholecystitis and cholelithiasis

Images

The importance of appropriate frequency selection in sonographic gallstone detection

A prospective study was performed on 161 patients referred for gallbladder ultrasound to determine whether routine use of a 5 MHz probe in addition to a standard 3.5 MHz probe provided useful additional information. Seventy-two patients were found to have gallstones. In 26.4% of these patients (19 cases) a confident diagnosis of gallstones was possible only when the 5 MHz probe was used. These results confirm theoretical assertions on the value of high-frequency probes in the evaluation of superficially located organs such as the gallbladder. Our findings lend support to their routine use in cholecystosonography.

Pitfalls in the ultrasonographic diagnosis of gallbladder diseases

Ultrasonography is rapidly replacing radiological techniques of gallbladder investigation. While ultrasonography is highly accurate, there are technical, anatomical and diagnostic pitfalls which will trap the unwary. This presentation highlights the pitfalls which we have encountered, reviews the literature in this area and suggests techniques whereby these pitfalls may be avoided.

Strong acoustical shadowing from the gallbladder bed: ultrasonic-pathologic correlation

We reviewed a series of 25 patients whose cholecystosonograms showed ultrasonic nonvisualization of the gallbladder, high-amplitude echoes in the region of the gallbladder bed, and strong acoustical shadowing. These 3 findings have previously been thought to be a reliable indication of a small contracted gallbladder filled with stones. In our series, all 25 such patients did not have gallstones, but the size and number of the calculi were highly variable. Only a small minority of our patients had a contracted gallbladder in most, the volume of the gallbladder was either normal or greater than normal. Ultrasonic nonvisualization of the gallbladder accompanied by acoustical shadowing was not a reliable indicator of gallbladder wall thickness in our series. Of 25 patients, 20 had either a normal gallbladder wall or only slight thickening. When we reviewed our images to determine how many fit the "WES" criteria thought to be a specific manifestation of a contracted gallbladder filled with stones, we found that 14 of 25 individuals clearly showed this group of ultrasonic findings. We could not, however, correlate the presence or absence of the 'WES' triad with the number and size of stones, the gallbladder volume, or thickness of the gallbladder wall.