บทคัดย่ออาการปวดเฉียบพลันควอดร้อนท์ด้านบนขวาเป็นอาการนำทั่วไปในผู้ป่วยที่มี cholecystitis เฉียบพลัน เมื่อเป็นที่สงสัย cholecystitis เฉียบพลันในผู้ป่วยที่มีอาการปวดควอดร้อนท์ขวาด้านบน ในสถานการณ์ทางคลินิกมากที่สุด modality ถ่ายภาพเริ่มต้นที่เลือกเป็นซาวด์ ถึงแม้ว่า cholescintigraphy ได้รับการแสดงจะมีความไวสูงขึ้นเล็กน้อยและ specificity ในการวินิจฉัย อัลตร้าซาวด์คือต้องเป็นการศึกษาที่เริ่มต้นสำหรับหลากหลายเหตุผล รวมถึงความพร้อมใช้งานมากขึ้น เวลาสอบสั้น ขาดการ ionizing รังสี ประเมิน morphologic ยืนยันสถานะหรือขาดของนิ่ว ประเมินผลของการที่ ท่อน้ำดี และรหัสหรือตัดการวิเคราะห์ทางเลือก CT หรือ MRI อาจจะมีประโยชน์ในกรณี equivocal และอาจระบุภาวะแทรกซ้อนของ cholecystitis เฉียบพลัน เมื่ออัลตร้าซาวด์พบ inconclusive, MRI เป็นการทดสอบถ่ายภาพที่ต้องการในผู้ป่วยตั้งครรภ์ที่ปัจจุบัน มีอาการปวดควอดร้อนท์ขวาบนเกณฑ์ความ ACR เป็นหลักฐานตามแนวทางสำหรับคลินิกเฉพาะเงื่อนไขที่จะตรวจสอบทุก 2 ปี โดยใช้แผง multidisciplinary การพัฒนาผลงานและตรวจสอบรวมวรรณกรรมทางการแพทย์ปัจจุบันจากเพียร์ตรวจสอบสมุดรายวันการวิเคราะห์อย่างละเอียดและใช้วิธีช่วยให้ดีขึ้น (ปรับเปลี่ยนเดลฟี) อันดับความของภาพและการรักษาตาม ในกรณีผู้ที่ขาดหลักฐาน หรืออาจใช้ความเห็นไม่ทั่วไป ผู้เชี่ยวชาญแนะนำภาพหรือการรักษาKeywords: Appropriateness Criteria, cholescintigraphy, ultrasound, cholecystitis, abdominal pain, comparative studiesGo to:SUMMARY OF LITERATURE REVIEWIntroduction/BackgroundAcute right upper quadrant pain is very common as a presenting symptom in hospital emergency departments and occasionally in patients hospitalized initially for unrelated conditions. This review focuses largely on the diagnostic accuracy of imaging studies performed to evaluate acute cholecystitis (AC), the primary diagnostic concern in the setting of acute right upper quadrant pain.AC may be life threatening, so correct, timely diagnosis is essential for proper treatment. However, information derived only from clinical history, physical examination, and routine laboratory tests has not yielded acceptable likelihood ratios sufficient to predict the presence or absence of AC. Also, this information does not yield sufficient diagnostic certainty for making management decisions. Imaging studies, therefore, play a major role in establishing a diagnosis of AC and assessing possible alternative diagnoses if AC is not present [1].Radiography of the abdomen is of limited value for evaluating right upper quadrant pain. Although abdominal radiography performed for initial evaluation may identify gallstones, they are not sufficient for establishing diagnoses of AC. Ultrasound and cholescintigraphy are the imaging studies most often used to diagnose AC. CT, however, may confirm or refute the diagnosis and reveal complications that are less clearly identified using other imaging modalities. Several studies support the diagnostic potential for MRI in patients with suspected AC; however, its use has yet to be fully assessed (see Variants 1–4).Variant 1Variant 1Fever, elevated white blood cell count, positive Murphy signVariant 4Variant 4Hospitalized patient with fever, elevated white blood cell count, and positive Murphy signUltrasound and CholescintigraphyAn initial study in 1981 defined the sonographic Murphy sign as focal tenderness corresponding to a sonographically localized gallbladder, which, along with stones, sludge, and gallbladder wall thickening, allowed the separation of AC from gallstones alone and chronic cholecystitis with gallstones [2]. Unfortunately, the sonographic Murphy sign has relatively low specificity for AC [3], and its absence is unreliable as a negative predictor of AC if the patient has received pain medication before imaging. Since that initial study, many subsequent studies have been conducted to assess the accuracy of ultrasound and cholescintigraphy. In a meta-analysis, Shea et al [4] reviewed 22 studies evaluating cholescintigraphy and 5 studies evaluating ultrasound published between 1978 and 1990. The authors concluded that cholescintigraphy demonstrated the best sensitivity (97%; 95% confidence interval [CI]: 96%, 98%) and specificity (90%; 95% CI: 86%, 95%) in detecting AC, whereas ultrasound had sensitivity of 88% (95% CI: 74%, 100%) and specificity of 80% (95% CI: 62%, 98%).A 2012 meta-analysis by Kiewiet et al [5] built on the results of Shea et al [4] and included 40 studies evaluating cholescintigraphy and 26 studies evaluating ultrasound published between 1978 and 2010. This analysis confirmed the sensitivity and specificity values noted by Shea et al, with cholescintigraphy at 96% (95% CI: 94%, 97%) and 90% (95% CI: 86%, 93%), respectively. However, Kiewiet et al reported slightly lower sensitivity of ultrasound at 81% (95% CI: 75%, 87%) and slightly higher specificity at 83% (95% CI: 74%, 89%). Similarly, direct comparisons of the diagnostic accuracy of ultrasound and cholescintigraphy performed in 11 studies confirmed the superior accuracy of cholescintigraphy.Although cholescintigraphy is recognized to have higher sensitivity and specificity, ultrasound remains the initial test of choice for imaging patients with suspected AC for a variety of reasons, including greater availability, shorter study time, lack of ionizing radiation, morphologic evaluation, confirmation of the presence or absence of gallstones, evaluation of intrahepatic and extrahepatic bile ducts, and identification or exclusion of alternative diagnoses [2,6–8].Despite providing information limited to the hepatobiliary tract, cholescintigraphy has been advocated as a useful preoperative modality. Specifically, findings of gallbladder nonvisualization or gallbladder ejection fraction <30% are noted to be useful in predicting the severity of cholecystitis and are associated with a higher complication rate in the setting of laparoscopic cholecystectomy [9]. Ideally, the surgeon or emergency physician, in consultation with the radiologist, should determine the role of scintigraphy in each case [10–14].CTAlthough it has not been advocated as a primary imaging examination for acute right upper quadrant pain, CT can confirm or refute the diagnosis of AC in equivocal cases on the basis of ultrasound and/or scintigraphic findings and reveal such complications as gangrene, gas formation, intraluminal hemorrhage, and perforation [6–8,15–19]. Furthermore, CT has been advocated as a useful modality in preoperative planning, with the absence of gallbladder wall enhancement and/or the presence of a stone within the infundibulum associated with conversion from laparoscopic to open cholecystectomy. Prior knowledge of these imaging findings may therefore help guide the appropriate surgical approach [20].Clinical conditions that can mimic AC, in terms of presentation with acute right upper quadrant pain, include chronic cholecystitis, peptic ulcer, pancreatitis, gastroenteritis, and bowel obstruction, among others. If ultrasound and/or scintigraphic results are negative for AC and there is no alternative diagnosis, CT, preferably with intravenous contrast, is the next preferred imaging examination for identifying those disorders. When a diagnosis of AC is not prospectively suspected, CT may also be used to demonstrate AC in patients who have nonspecific abdominal pain.MRIAC can be confirmed or excluded by abdominal MRI using various protocols, which often include the use of an intravenous gadolinium-based contrast agent. As with CT, MRI is not advocated as a primary imaging examination to evaluate acute right upper quadrant pain; however, several studies have suggested that abdominal MRI is a reliable alternative and can be particularly helpful in patients who are difficult to examine with ultrasound [21–23]. Although factors such as longer acquisition times limit its use in the emergency setting, less interpreter variability and more consistent visualization of the extrahepatic biliary tree are important advantages of its use [24, 25]. MRI can be the next best imaging modality when AC is excluded, and it is considered the best modality for evaluating hepatic and biliary abnormalities that are not characterized by ultrasound.Few studies have examined the role of MRI in evaluating AC. On the basis of the available literature encompassing several small studies, MRI sensitivity estimates range from 50% to 91%, with specificities ranging from 79% to 89%. According to the meta-analysis by Kiewiet et al [5], the summary sensitivity is 85% (95% CI: 66%, 95%), and specificity is 81% (95% CI: 69%, 90%) [23–25], similar to those of ultrasound. Additional studies with larger sample sizes are needed to better clarify the role of abdominal MRI in evaluating AC.Pregnant PatientsAs in the general population, ultrasound is the imaging test of choice for evaluating AC in pregnant patients (see Variant 5). MRI is the preferred test to follow inconclusive ultrasound, as it can be used to evaluate the entire biliary system and diagnose other causes of acute abdominal pain without exposing the patient to ionizing radiation. MR cholangiopancreatography is helpful in identifying patients who require immediate intervention for pancreatic or biliary pathology. It also helps guard against unnecessary endoscopic retrograde cholangiopancreatography by excluding a biliary abnormality when ultrasound findings are equivocal. Note that during pregnancy, intravenous gadolinium is generally not administered, as it is a class III agent in pregnancy [26,27].Variant 5Variant 5Fever, leukocytosis, pregnant patientAcalculous CholecystitisThe diagnosis of acute acalculous cholecystitis (AAC) is more problematic than that of calculous AC (see Variant 6).
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