复旦大学上海医学院：《医学影像学》PPT教学课件_胆道超声检查 Ultrasound of the Biliary tract

391 ULTRASOUND CLINICS ELSEVIER SAUNDERS sound clin2(2007391-413 Ultrasound Imaging of the Biliary Tract Deborah」. Rubens,MD Inflammatory disorders: cholecystitis Benign neoplasms of the gallbladder The Sonographic Murphy's Sign Malignant neoplasms of the gallbladder Gallstones Biliary ducts Gallbladder wall thickening a Ultrasound diagnosis of biliary ductal and pericholecystic fluid dilatation Acute acalculous cholecystitis Diagnosis of biliary obstruction Complicated cholecystitis n Causes of biliary obstruction Choledocholithiasis Gallbladder perforation Ne。 plasm Inflammatory disorders of the biliary ducts Chronic cholecystitis Biliary air and biliary necrosis Noninflammatory non-neoplastic gallbladder disorders: the hyperplastic References cholecystoses-cholesterolosis and Patients who have disease of the biliary tract inflammation of the gallbladder wall. There may ommonly present with acute right upper quadrant or may not be associated infection and necrosis pain, nausea or vomiting, mid-epigastric pain, and/ Ninety to ninety-five percent of all cases of acute or jaundice. Etiologies include inflammation with cholecystitis are caused by obstruction of either or without infection, noninflammatory disorders, the cystic duct or the neck of the gallbladder by gal and benign or malignant neoplasms of the gallblad- stones 1. Acute cholecystitis, however, occurs in der or bile ducts. Ultrasound(us) is now accepted only approximately 20% of patients who have gall as the initial imaging modality of choice for the stones [2 This means that most gallstones are work-up of suspected biliary tract disease. asymptomatic. Thus, right upper quadrant pain in This article reviews the most common diseases of a patient who has gallstones often is caused by some- the gallbladder and bile ducts, strategies for evaluat- thing other than acute cholecystitis 3 Further- ing the biliary tract with ultrasound, and specific more, studies have shown that only 20%-35% of imaging patterns that aid in diagnosis patients presenting with right upper quadrant pain are subsequently shown to have acute cholecystitis Inflammatory disorders: cholecystitis 11, 2 Therefore, it is important to understand the sensitivity and specificity of common US findings Acute cholecystitis most often occurs secondary in patients who have acute cholecystitis, because to obstruction of the gallbladder with resultant the presence of gallstones alone is not adequate to University of Rochester Medical Center, Department of Imaging Sciences, 601 Elmwood Avenue, Rochester NY14642-8648,USA E-mail address. deborah rubens@urmc rochester edu 1556-858X/07/S-see front matter e 2007 Elsevier Inc. All rights reserved doi:10.1016/cut200708.00

Ultrasound Imaging of the Biliary Tract Deborah J. Rubens, MD Patients who have disease of the biliary tract commonly present with acute right upper quadrant pain, nausea or vomiting, mid-epigastric pain, and/ or jaundice. Etiologies include inflammation with or without infection, noninflammatory disorders, and benign or malignant neoplasms of the gallblad￾der or bile ducts. Ultrasound (US) is now accepted as the initial imaging modality of choice for the work-up of suspected biliary tract disease. This article reviews the most common diseases of the gallbladder and bile ducts, strategies for evaluat￾ing the biliary tract with ultrasound, and specific imaging patterns that aid in diagnosis. Inflammatory disorders: cholecystitis Acute cholecystitis most often occurs secondary to obstruction of the gallbladder with resultant inflammation of the gallbladder wall. There may or may not be associated infection and necrosis. Ninety to ninety-five percent of all cases of acute cholecystitis are caused by obstruction of either the cystic duct or the neck of the gallbladder by gall￾stones [1]. Acute cholecystitis, however, occurs in only approximately 20% of patients who have gall￾stones [2]. This means that most gallstones are asymptomatic. Thus, right upper quadrant pain in a patient who has gallstones often is caused by some￾thing other than acute cholecystitis [3]. Further￾more, studies have shown that only 20%–35% of patients presenting with right upper quadrant pain are subsequently shown to have acute cholecystitis [1,2]. Therefore, it is important to understand the sensitivity and specificity of common US findings in patients who have acute cholecystitis, because the presence of gallstones alone is not adequate to ULTRASOUND CLINICS Ultrasound Clin 2 (2007) 391–413 University of Rochester Medical Center, Department of Imaging Sciences, 601 Elmwood Avenue, Rochester, NY 14642-8648, USA E-mail address: deborah_rubens@urmc.rochester.edu - Inflammatory disorders: cholecystitis - The Sonographic Murphy’s Sign - Gallstones - Gallbladder wall thickening and pericholecystic fluid - Acute acalculous cholecystitis - Complicated cholecystitis - Gangrenous cholecystitis - Gallbladder perforation - Emphysematous cholecystitis - Chronic cholecystitis - Noninflammatory non-neoplastic gallbladder disorders: the hyperplastic cholecystoses—cholesterolosis and adenomyomatosis Benign neoplasms of the gallbladder Malignant neoplasms of the gallbladder - Biliary ducts - Ultrasound diagnosis of biliary ductal dilatation - Diagnosis of biliary obstruction - Causes of biliary obstruction Choledocholithiasis Neoplasm - Inflammatory disorders of the biliary ducts - Biliary air and biliary necrosis - Summary - References 391 1556-858X/07/$ – see front matter ª 2007 Elsevier Inc. All rights reserved. doi:10.1016/j.cult.2007.08.007 ultrasound.theclinics.com

392 Rub ↓ GB LO DEC GB LO SITTING LONG G B

392 Rubens

Ultrasound Imaging of the Biliary Tract 393 make the diagnosis of acute cholecystitis. The com- the gallbladder lumen that cast a posterior shadow bination of US findings that is most predictive of (Fig. 1). Although ultrasound has been demon- acute cholecystitis is the presence of a positive sone rated to have an accuracy (>95%)for the identifica Secondary signs on US examination of acute chole- <1 mm to cast a posterior shadow soft stones lacking graphic Murphy sign plus the presence of gallstones. tion of gallstones, stones that are too small, (usually cystitis include gallbladder wall thickening (>3 strong internal echoes 1 or gallstones impacted in Bs h ), a distended or hydropic gallbladder(loss of the gallbladder neck or in the cystic duct that may the normal tapered neck and development of an el- not be as readily detectable on US examination as liptic or rounded shape), and pericholecystic fluid. they silhouette with the surrounding echogenic bowel gas or intraperitoneal fat(see Fig. 1)15.If The sonographic Murphy,'s sign the gallbladder is focally tender but no gallstones are appreciated the patient should be examined The sonographic Murphy sign is defined as repro- from multiple positions and scanning planes, ducible point tenderness specifically over the gall- cluding prone, upright and decubitus positions bladder upon application of pressure by the and intercostal scanning, to facilitate complete visu transducer Ralls and colleagues [4] wrote a classic alization of the neck of the gallbladder [3, 61 article that reported a sonographic Murphy sign Harmonic imaging significantly improves visual was 87% specific for the diagnosis of acute ization of small gallstones. This type of ultrasound cholecystitis, in a patient population which only in- transmits the insonating us beam at a fundamental cluded patients who had right upper quadrant pain, frequency, such as 2.5 or 3 MHz, and receives the re- fever and an elevated white blood cell count. Laing turning echoes not only at the fundamental fre and colleagues [5| reported that the presence of quency but also at the second harmonic frequency a positive sonographic Murphys sign in combina- that is twice the fundamental frequency creating tion with the presence of gallstones has a positive the image with the higher harmonic frequency predictive value of 92%for the diagnosis of acute 17-9 By eliminating the fundamental frequency, cholecystitis. In order to avoid false positive exami- this technique significantly reduces degradation of lations, one must be careful to elicit pain directly the image by noise, since lower frequencies easily over the gallbladder, not diffusely in epigastrium, can be filtered out. In addition, scattering of the or over the liver edge. False negative examinations US beam from fat in the anterior abdominal wall may occur in patients who have received pain med- is diminished because the harmonic frequencies icine, patients who are taking steroids, para or are generated after the beam enters the body. The quadriplegics, or any patient who is not able to narrower harmonic beam also has fewer side lobes, give a reliable history or pain response. In addition, and therefore, improved lateral resolution and sig. the sonographic Murphy s sign may be absent in de- nal to noise ratio. Harmonic imaging increases nervated gallbladders, for example, in patients who the echogenicity of gallstones and strengthens have diabetes or gangrenous cholecystitis. A sono. their posterior shadows, permitting visualization diminished if the gallbaldder ruptures because ultrasound(see Fig. 1). Another technique that im this will relieve the obstruction. Therefore, careful proves visualization of stones is spatial compound attention to the patient's clinical status is important ing. Multiple images are acquired slightly off axis when assessing for a sonographic Murphy's sig from one another, which increases the signal from the persistent echoes that comprise the image and Gallstones blurs out some of the random noise. the disadvan- Gallstones are diagnosed on US by the presence of tage of compounding is that posterior shadowing is diminished, which may be a better visual cue to gravity-dependent, mobile, echogenic foci within dete llstones than the actual echoes Fig 1. Gallstones. (A)(Left) Gallstone in the gallbladder neck (arrow) casts no significant shadow and is nearly invisible. Gas in the duodenum(arrowhead)obscures the fundus of the gallbladder and casts a strong sharp shadow(asterisk).(Right) With patient in sitting position, stone (arrow)moves out of the neck and casts a clear shadow (asterisk). Adjacent duodenum(arrowheads) is now separate from the gallbladder but still casts a strong shadow, equivalent to the gallstone. B)(Left)Multiple gallstones(arrowheads), some of which cast shadow (arrows), whereas others do not. (Right) Normal caliber common duct( 6 mm at the porta)with stones(arrows) in the same patient. Choledocholithiasis may be difficult to detect, especially in the distal duct, if the stones do not shadow or are not outlined by fluid (o(Left) Longitudinal ultrasound shows a normal gallbladder. ( Right) Harmonic imaging reveals multiple small stones(arrows).(From Rubens D Hepatobiliary imaging and its pitfalls Radiol Clin North Am 2004: 42: 257-78: with permission

make the diagnosis of acute cholecystitis. The com￾bination of US findings that is most predictive of acute cholecystitis is the presence of a positive sono￾graphic Murphy’ sign plus the presence of gallstones. Secondary signs on US examination of acute chole￾cystitis include gallbladder wall thickening (>3 mm), a distended or hydropic gallbladder (loss of the normal tapered neck and development of an el￾liptic or rounded shape), and pericholecystic fluid. The sonographic Murphy’s sign The sonographic Murphy sign is defined as repro￾ducible point tenderness specifically over the gall￾bladder upon application of pressure by the transducer. Ralls and colleagues [4] wrote a classic article that reported a sonographic Murphy sign was 87% specific for the diagnosis of acute cholecystitis, in a patient population which only in￾cluded patients who had right upper quadrant pain, fever and an elevated white blood cell count. Laing and colleagues [5] reported that the presence of a positive sonographic Murphy’s sign in combina￾tion with the presence of gallstones has a positive predictive value of 92% for the diagnosis of acute cholecystitis. In order to avoid false positive exami￾nations, one must be careful to elicit pain directly over the gallbladder, not diffusely in epigastrium, or over the liver edge. False negative examinations may occur in patients who have received pain med￾icine, patients who are taking steroids, para or quadriplegics, or any patient who is not able to give a reliable history or pain response. In addition, the sonographic Murphy’s sign may be absent in de￾nervated gallbladders, for example, in patients who have diabetes or gangrenous cholecystitis. A sono￾graphic Murphy’s sign also may be significantly diminished if the gallbaldder ruptures because this will relieve the obstruction. Therefore, careful attention to the patient’s clinical status is important when assessing for a sonographic Murphy’s sign. Gallstones Gallstones are diagnosed on US by the presence of gravity-dependent, mobile, echogenic foci within the gallbladder lumen that cast a posterior shadow (Fig. 1). Although ultrasound has been demon￾strated to have an accuracy (>95%) for the identifica￾tion of gallstones, stones that are too small, (usually <1 mm to cast a posterior shadow soft stones lacking strong internal echoes [1], or gallstones impacted in the gallbladder neck or in the cystic duct that may not be as readily detectable on US examination as they silhouette with the surrounding echogenic bowel gas or intraperitoneal fat (see Fig. 1) [5]. If the gallbladder is focally tender but no gallstones are appreciated, the patient should be examined from multiple positions and scanning planes, in￾cluding prone, upright and decubitus positions and intercostal scanning, to facilitate complete visu￾alization of the neck of the gallbladder [3,6]. Harmonic imaging significantly improves visual￾ization of small gallstones. This type of ultrasound transmits the insonating US beam at a fundamental frequency, such as 2.5 or 3 MHz, and receives the re￾turning echoes not only at the fundamental fre￾quency but also at the second harmonic frequency that is twice the fundamental frequency creating the image with the higher harmonic frequency [7–9]. By eliminating the fundamental frequency, this technique significantly reduces degradation of the image by noise, since lower frequencies easily can be filtered out. In addition, scattering of the US beam from fat in the anterior abdominal wall is diminished because the harmonic frequencies are generated after the beam enters the body. The narrower harmonic beam also has fewer side lobes, and therefore, improved lateral resolution and sig￾nal to noise ratio. Harmonic imaging increases the echogenicity of gallstones and strengthens their posterior shadows, permitting visualization of stones not seen with conventional grayscale ultrasound (see Fig. 1). Another technique that im￾proves visualization of stones is spatial compound￾ing. Multiple images are acquired slightly off axis from one another, which increases the signal from the persistent echoes that comprise the image and blurs out some of the random noise. The disadvan￾tage of compounding is that posterior shadowing is diminished, which may be a better visual cue to detect typical gallstones than the actual echoes Fig. 1. Gallstones. (A) (Left) Gallstone in the gallbladder neck (arrow) casts no significant shadow and is nearly invisible. Gas in the duodenum (arrowhead) obscures the fundus of the gallbladder and casts a strong sharp shadow (asterisk). (Right) With patient in sitting position, stone (arrow) moves out of the neck and casts a clear shadow (asterisk). Adjacent duodenum (arrowheads) is now separate from the gallbladder but still casts a strong shadow, equivalent to the gallstone. (B) (Left) Multiple gallstones (arrowheads), some of which cast shadows (arrows), whereas others do not. (Right) Normal caliber common duct (6 mm at the porta) with stones (arrows) in the same patient. Choledocholithiasis may be difficult to detect, especially in the distal duct, if the stones do not shadow or are not outlined by fluid. (C) (Left) Longitudinal ultrasound shows a normal gallbladder. (Right) Harmonic imaging reveals multiple small stones (arrows). (From Rubens D. Hepatobiliary imaging and its pitfalls. Radiol Clin North Am 2004;42:257–78; with permission.) : Ultrasound Imaging of the Biliary Tract 393

394 Rub GB

394 Rubens

Ultrasound Imaging of the Biliary Tract 395 hile harmonic imaging definitely improves detection, spatial com- pounding remains optional on an individual case basis Other stones such as soft pigment stones may not shadow with any technique. Soft pigment stones are less echogenic than the more cor terol gallstones and may simulate soft tissue asses. Pigmented stones are commonly associated with recurrent pyogenic cholangiohepatitis and are nore often seen in the bile ducts than in the gall bladder. Because of their lack of shadowing, they may be misinterpreted as sludge or debris and result in a false negative examination False positive Us diagnosis of gallstones may oc- cur secondary to side lobe artifacts that can generate Fig 3. Acute cholecystitis. This patient presented with echoes appearing to arise within the gallbladder lu- RUQ pain and had a positive se men but actually te from the wall or outside sign. Longitudinal ultrasound shows stones (arrows) the wall (1 . Similarly, gas in adjacent bowel can cre and diffuse gallbladder wall thickening (cursors) ate a brightly echogenic mass-like area with poste- measuring 5 mm (From Harrow A. The gallbladder rior shadowing which appears to be within the and biliary tree. In: Dogra V, Rubens D, editors. Ultra- gallbladder lumen because of a partial volume art fact and thereby mimics gallstones(Fig. 1A). A cal- p. 113-29: with permission.) cium bile salt precipitate may form in patients taking the antibiotic ceftriaxone and may mimic finding, because numerous other etiologies such gallstones on sonographic examination. These pre- as hepatic congestion or edema, congestive heart e anter patient failure, or hypoproteinemia(often associated with Other fluid-containing structures such as the renal disease or hepatic dysfunction)can cause duodenum,gastric antrum,colon, hematomas, pan- thickening of the gallbladder wall. Adenomyomato- creatic pseudocysts(Fig. 2), or even dilated vascular sis and cancer of the gall bladder also may result in collaterals may be mistaken for the gallbladder on thickening of the gallbladder wall (3).A thickened US examination, especially if the gallbladder is gallbladder wall also can occur in association with out of its normal position or is small and con- viral infections and adjacent inflammatory condi tracted. Mistaking these structures for the gallblad- tions, including hepatitis, peptic ulcer disease der may result in missing pathology in the true (Fig. 4), pancreatitis, perihepatitis(Fitz-Hugh- gallbladder or a false-positive diagnosis of gallblad- Curtis syndrome), and pyelonephritis(Fig. 5).In der disease(ie, obstructed gallbladder or acalculous patients who have thickening of the gallbladder cholecystitis) wall caused by etiologies other than acute cholecys- titis, the gallbladder often is nondistended, imply Gallbladder wall thickening ng a nonobstructive(non-biliary) cause of wall cystic flt thickening(Fig. 6) Thickened gallbladder wall demonstrating a stri Gallbladder wall thickening is defined as a wall ated appearance with alternating hyper- and hypo- diameter greater than 3 mm and is present in echoic layers in the setting of acute cholecystitis is 50%of patients who have acute cholecystitis strongly associated gangrenous cholecystitis [101 (Fig. 3)|1 However, this is a very non-specific However, striations in the gallbladder wall without Fig. 2. Pseudo gallbladders. (A) Transverse image in the right upper gallbladder" does not extend anteriorly and that the aorta (a)is immediately adjacent. B)(Left) CT image of the same area as in(a)showed a fluid-contain ing structure with similar attenuation to blood in the aorta(A). This was a retroperitoneal hematoma in an anti- coagulated patient. B)(Right) The true gallbladder(GB)is lateral to the aorta and extends anteriorly. (o)(Left) Fluid and debris-containing structure believed to represent an abnormal gallbladder(GB)in this patient who had RUQ pain (Right) The true gallbladder(arrows) is compressed and displaced by the adjacent mass, a pan creatic pseudocyst. (D)CT of the pancreatic pseudocyst(P) displacing the gallbladder(arrows).(From Rubens D. Hepatobiliary imaging and its pitfalls. Radiol Clin North Am 2004: 42: 257-78: with permission

from the stones themselves. So, while harmonic imaging definitely improves detection, spatial com￾pounding remains optional on an individual case basis. Other stones such as soft pigment stones may not shadow with any technique. Soft pigment stones are less echogenic than the more common choles￾terol gallstones and may simulate soft tissue masses. Pigmented stones are commonly associated with recurrent pyogenic cholangiohepatitis and are more often seen in the bile ducts than in the gall￾bladder. Because of their lack of shadowing, they may be misinterpreted as sludge or debris and result in a false negative examination. False positive US diagnosis of gallstones may oc￾cur secondary to side lobe artifacts that can generate echoes appearing to arise within the gallbladder lu￾men but actually originate from the wall or outside the wall [1]. Similarly, gas in adjacent bowel can cre￾ate a brightly echogenic mass-like area with poste￾rior shadowing, which appears to be within the gallbladder lumen because of a partial volume arti￾fact and thereby mimics gallstones (Fig. 1A). A cal￾cium bile salt precipitate may form in patients taking the antibiotic ceftriaxone and may mimic gallstones on sonographic examination. These pre￾cipitates resolve after the patient ends therapy. Other fluid-containing structures such as the duodenum, gastric antrum, colon, hematomas, pan￾creatic pseudocysts (Fig. 2), or even dilated vascular collaterals may be mistaken for the gallbladder on US examination, especially if the gallbladder is out of its normal position or is small and con￾tracted. Mistaking these structures for the gallblad￾der may result in missing pathology in the true gallbladder or a false-positive diagnosis of gallblad￾der disease (ie, obstructed gallbladder or acalculous cholecystitis). Gallbladder wall thickening and pericholecystic fluid Gallbladder wall thickening is defined as a wall diameter greater than 3 mm and is present in 50% of patients who have acute cholecystitis (Fig. 3) [1]. However, this is a very non-specific finding, because numerous other etiologies such as hepatic congestion or edema, congestive heart failure, or hypoproteinemia (often associated with renal disease or hepatic dysfunction) can cause thickening of the gallbladder wall. Adenomyomato￾sis and cancer of the gall bladder also may result in thickening of the gallbladder wall [3]. A thickened gallbladder wall also can occur in association with viral infections and adjacent inflammatory condi￾tions, including hepatitis, peptic ulcer disease (Fig. 4), pancreatitis, perihepatitis (Fitz-Hugh￾Curtis syndrome), and pyelonephritis (Fig. 5). In patients who have thickening of the gallbladder wall caused by etiologies other than acute cholecys￾titis, the gallbladder often is nondistended, imply￾ing a nonobstructive (non-biliary) cause of wall thickening (Fig. 6). A thickened gallbladder wall demonstrating a stri￾ated appearance with alternating hyper- and hypo￾echoic layers in the setting of acute cholecystitis is strongly associated gangrenous cholecystitis [10]. However, striations in the gallbladder wall without Fig. 2. Pseudo gallbladders. (A) Transverse image in the right upper quadrant (RUQ) with structure identified as the gallbladder (arrows) containing debris (asterisk). Note that the ‘‘gallbladder’’ does not extend anteriorly and that the aorta (A) is immediately adjacent. (B) (Left) CT image of the same area as in (A) showed a fluid-contain￾ing structure with similar attenuation to blood in the aorta (A). This was a retroperitoneal hematoma in an anti￾coagulated patient. (B) (Right) The true gallbladder (GB) is lateral to the aorta and extends anteriorly. (C) (Left) Fluid and debris-containing structure believed to represent an abnormal gallbladder (GB) in this patient who had RUQ pain. (Right) The true gallbladder (arrows) is compressed and displaced by the adjacent mass, a pan￾creatic pseudocyst. (D) CT of the pancreatic pseudocyst (P) displacing the gallbladder (arrows). (From Rubens D. Hepatobiliary imaging and its pitfalls. Radiol Clin North Am 2004;42:257–78; with permission.) : Fig. 3. Acute cholecystitis. This patient presented with RUQ pain and had a positive sonographic Murphy sign. Longitudinal ultrasound shows stones (arrows) and diffuse gallbladder wall thickening (cursors) measuring 5 mm. (From Harrow A. The gallbladder and biliary tree. In: Dogra V, Rubens D, editors. Ultra￾sound secrets. Philadelphia: Hanley and Belfus; 2004. p. 113–29; with permission.) Ultrasound Imaging of the Biliary Tract 395