Contrast-enhanced ultrasonography to diagnose complicated acute cholecystitis

Gangrenous cholecystitis and perforation are severe complications of acute cholecystitis, which have a challenging preoperative diagnosis. Early identification allows better surgical management. Contrast-enhanced computed tomography (ceCT) is the current diagnostic gold standard. Contrast-enhanced ultrasonography (CEUS) is a promising tool for the diagnosis of gallbladder perforation, but data from the literature concerning efficacy are sparse. The aim of the study was to evaluate CEUS findings in pathologically proven complicated cholecystitis (gangrenous, perforated gallbladder, pericholecystic abscess). A total of 8 patients submitted to preoperative CEUS, and with subsequent proven acute complicated cholecystitis at surgical inspection and pathological analysis, were retrospectively identified. The final diagnosis was gangrenous/phlegmonous cholecystitis (n. 2), phlegmonous/ulcerative changes plus pericholecystic abscess (n. 2), perforated plus pericholecystic abscess (n. 3), or perforated plus pericholecystic biliary collection (n. 1). Conventional US findings revealed irregularly thickened gallbladder walls in all 8 patients, with vaguely defined walls in 7 patients, four of whom also had striated wall thickening. CEUS revealed irregular enhancing gallbladder walls in all patients. A distinct wall defect was seen in six patients, confirmed as gangrenous/phlegmonous cholecystitis at pathology in all six, and in four as perforation at macroscopic surgical inspection. CEUS is a non-invasive easily repeatable technique that can be performed at the bedside, and is able to accurately diagnose complicated/perforated cholecystitis. Despite the limited sample size in the present case series, CEUS appears as a promising tool for the management of patients with the clinical possibility of having an acute complicated cholecystitis.     

A case of pericholecystic abscess diagnosed by ultrasonography

Pericholecystic abscess is a serious complication of cholecystitis. Though preoperative diagnosis is easy by gray-scale ultrasonography, there has been no case reported in which the communication between pericholecystic abscess and the gallbladder was demonstrated ultrasonically. We experienced a case in which the communication route between a pericholecystic abscess and the gallbladder was successfully demonstrated by a real-time electric linear scanner. Furthermore, the abscess was successfully treated by percutaneous drainage following ultrasonically guided puncture. This success demonstrates that ultrasonography by a real-time scanner can be effective for diagnosis and treatment of acute cholecystitis and pericholecystic abscess.     

Preoperative diagnosis of gallbladder torsion by magnetic resonance cholangiopancreatography

The patient was a 78-year-old woman who was diagnosed as having gallbladder torsion preoperatively. This is the first reported case diagnosed by magnetic resonance cholangiopancreatography (MRCP). Signs and symptoms of this condition are often subtle. Radiologic evaluation by ultrasonography and computed tomography (CT) showed acute cholecystitis with stone. Drip-infusion cholangiography CT failed to outline the gallbladder, and distortion of the extrahepatic bile ducts and interruption of the cystic duct were observed. MRCP showed 1) a v-shaped distortion of the extrahepatic bile ducts due to traction by the cystic duct, 2) tapering and twisting interruption of the cystic duct, 3) a distended and enlarged gallbladder that was deviated to the midline of the abdomen, and 4) a difference in intensity between the gallbladder and the extrahepatic bile ducts and the cystic duct. A definitive diagnosis of gallbladder torsion (volvulus) was made by MRCP preoperatively. If treated surgically, gallbladder detorsion before cholecystectomy is a helpful technique to avoid bile duct injury. This condition should be suspected in elderly women with acute cholecystitis or acute abdominal pain of unknown origin, and MRCP may be very useful in making a definitive diagnosis.     

Preoperative Diagnosis of Gallbladder Torsion by Magnetic Resonance Cholangiopancreatography

The patient was a 78-year-old woman who was diagnosed as having gallbladder torsion preoperatively. This is the first reported case diagnosed by magnetic resonance cholangiopancreatography (MRCP). Signs and symptoms of this condition are often subtle. Radiologic evaluation by ultrasonography and computed tomography (CT) showed acute cholecystitis with stone. Drip-infusion cholangiography CT failed to outline the gallbladder, and distortion of the extrahepatic bile ducts and interruption of the cystic duct were observed. MRCP showed 1) a v-shaped distortion of the extrahepatic bile ducts due to traction by the cystic duct, 2) tapering and twisting interruption of the cystic duct, 3) a distended and enlarged gallbladder that was deviated to the midline of the abdomen, and 4) a difference in intensity between the gallbladder and the extrahepatic bile ducts and the cystic duct. A definitive diagnosis of gallbladder torsion (volvulus) was made by MRCP preoperatively. If treated surgically, gallbladder detorsion before cholecystectomy is a helpful technique to avoid bile duct injury. This condition should be suspected in elderly women with acute cholecystitis or acute abdominal pain of unknown origin, and MRCP may be very useful in making a definitive diagnosis.     

The role of the Tokyo guidelines in the diagnosis of acute calculous cholecystitis

Background

Acute calculous cholecystitis is a condition in which the gallbladder becomes inflamed due to cholelithiasis. Early diagnosis reduces both mortality and morbidity. The aim of this retrospective study was to assess the diagnostic value of the Tokyo guidelines in patients with acute cholecystitis.

Methods

The medical records of patients admitted for acute calculous cholecystitis proven by pathological findings were collected between January 2007 and June 2008. Exclusion criteria included: acalculous cholecystitis, hepatobiliary malignancy, patients younger than 18 years and mortality unrelated to cholecystitis. A total of 235 patients were classified into three groups according to the severity grading in the Tokyo guidelines. Clinical characteristics among these patients were analyzed for comparison.

Results

Among all diagnostic criteria, right upper quarter (RUQ) abdominal pain (97.9%) and thickened gallbladder wall (92.3%) had the highest sensitivity rates, whereas pericholecystic fluid collection (18.3%) and RUQ abdominal mass (0.8%) had the lowest sensitivity rates. Higher sensitivity rates of diagnostic criteria were related to severe cholecystitis, except for Murphy’s sign and white blood cell (WBC) count. The presence of both RUQ abdominal pain and elevated C-reactive protein (55.1%), or both RUQ abdominal pain and elevated WBC count (53.7%), accounted for the highest sensitivity rates in making the definite diagnosis of acute cholecystitis. Seventeen patients (7.2%) without comparable typical image findings were prone to be afebrile and had normal C-reactive protein values compared to those with typical image findings.

Conclusion

Among all diagnostic criteria in the Tokyo guidelines for acute cholecystitis, RUQ abdominal pain and thickened gallbladder wall had the highest sensitivity rates, and RUQ abdominal mass had the lowest sensitivity rate. A combination of diagnostic criteria with different pathophysiologic findings, as noted in the Tokyo guidelines, can help clinicians make the correct diagnosis for patients with acute calculous cholecystitis.     

Experience with 1904 laparoscopic cholecystectomies at a private hospital

The purpose of this paper is to describe our recent experience in performing laparoscopic cholecystectomies of which we performed 1904, from January 1991 to May 1997, at our private hospital, mainly to treat cholecystolithiasis. The patients included 1563 with gallbladder stones (82.0%), 82 with cholecystocholedocholithiasis (4.3%), 104 with adenomyomatosis (5.5%), 132 with polyps (6.9%), and 23 with gallbladder cancer (1.3%). A difficult pericholecystic dissection led to conversion to open surgery in 61 patients. The average operation time was 63 min. Bile duct injury or cystic artery bleeding occurred in 3 patients with acute cholecystitis, and small intestine injury occurred in 1 patient, while bile leakage or a right subphrenic abscess occurred in 6 patients postoperatively. Although this series included 69 patients with previous upper abdominal surgery, 14 with liver cirrhosis, 267 with a nonvisualized gallbladder, and 148 with acute cholecystitis, the overall conversion rate was only 3.2% and morbidity only 0.5%. Although almost all patients with cholelithiasis are now considered potential candidates for a laparoscopic cholecystectomy, difficulties during cholecystectomy have been encountered in patients with acute cholecystitis. Surgeons should thus be fully prepared to convert to open surgery whenever difficulties are encountered, in order to avoid complication.     

Hypointense gallbladder on MR cholangiopancreatography

A few patients show a gallbladder of poor visibility on magnetic resonance cholangiopancreatography (MRCP) images due to various reasons. A 45-year-old man was referred with abdominal pain and fever. In contrast enhanced computed tomography, several calcified gallstones were observed in the gallbladder. Although a solitary calcified stone was seen in the neck of the gallbladder, neither stones in the common bile duct (CBD) nor dilatation of CBD were observed. On MRCP, hypointense gallbladder with no filling defect in the CBD was observed. Histopathological analysis of the gallbladder, which was obtained by laparoscopic cholecystectomy, confirmed severe chronic cholecystitis with several calcified gallstones up to 0.5 cm in diameter. In conclusion, the finding of hypointense gallbladder on MRCP in patients with cholecystitis and its underlying condition, though rare, should be kept in mind.     

Computed tomography as an adjunct to ultrasound in the diagnosis of acute acalculous cholecystitis

The sonographic and computed tomographic (CT) findings were reviewed in 17 patients with acute acalculous cholecystitis (AAC) over a 6-year period from 1984 to 1989. Of the six patients in whom both ultrasound and CT were performed, CT revealed marked gallbladder (GB) wall abnormalities, including perforation, and pericholecystic fluid collections in five patients not demonstrated by sonography. Of the total group, five patients had GB wall thicknesses of less than or equal to 3 mm (normal) at pathologic examination, which demonstrated a spectrum of disease ranging from acute hemorrhagic/necrotizing, to gangrenous acalculous cholecystitis with perforation. Sonography was falsely negative or significantly underestimated the severity of AAC in seven of the 13 patients examined by sonography. CT because of its superior ability to assess pericholecystic inflammation may provide additional diagnostic information even after a thorough sonographic study in cases of AAC.     

Conversión de colecistectomía laparoscópica a abierta: análisis de factores de riesgo con base en parámetros clínicos,de laboratorio y de ultrasonido

Introduction and aimsThe standard of care for gallbladder disease is laparoscopic cholecystectomy. Difficult dissection of the hepatocytic triangle and bleeding can result in conversion to open cholecystectomy, which is associated with increased morbidity. Identifying risk factors for conversion in the context of acute cholecystitis will allow patient care to be individualized and improve outcomes.Materials and methodsA retrospective case-control study included all patients diagnosed with acute cholecystitis, according to the 2018 Tokyo Guidelines, admitted to a tertiary care academic center, from January 1991 to January 2012. Using logistic regression, we analyzed variables to identify risk factors for conversion. Variables that were found to be significant predictors of conversion in the univariate analysis were included in a multivariate model. We then performed an exploratory analysis to identify the risk factor summation pathway with the highest sensitivity for conversion.ResultsThe study included 321 patients with acute cholecystitis. Their mean age was 49 years (±16.8 SD), 65% were females, and 35% were males. Thirty-nine cases (12.14%) were converted to open surgery. In the univariate analysis, older age, male sex, gallbladder wall thickness, and pericholecystic fluid were associated with a higher risk for conversion. In the multivariate analysis all of the variables, except pericholecystic fluid, were associated with conversion. Our risk factor summation model had a sensitivity of 84%.ConclusionsPreoperative clinical data can be utilized to identify patients with a higher risk of conversion to open cholecystectomy. Being aware of such risk factors can help improve perioperative planning and preparedness in challenging cases.     

Ultrasound in postoperative acalculous cholecystitis

Eleven patients were examined by ultrasound before undergoing cholecystectomy (n = 9) or cholecystostomy (n = 2) for acalculous cholecystitis after abdominal surgery. The ultrasound images were analyzed retrospectively and compared with the surgical and histologic findings. The results indicate several established ultrasound criteria of cholecystitis to be less reliable than usual. Although 10 of 11 patients were on parenteral hyperalimentation, gross distention of the gallbladder was observed in only 3. In 4 of 7 patients, in whom pericholecystic fluid was observed, no gallbladder perforation was found at surgery. However, thickening of the gallbladder wall was displayed in 10 of 11 cases, combined with a sonolucent intramural layer in 6. Furthermore, intraluminal nonshadowing echogenic densities correlated with empyema or hemorrhage in 5 of 8 cases. In conclusion, despite several limitations, ultrasound can be of considerable help when one is deciding to perform repeat laparotomy when acalculous cholecystitis is suspected.     

Acute acalculous cholecystitis

Acute cholecystitis can develop without gallstones in critically ill or injured patients. However, the development of acute acalculous cholecystitis is not limited to surgical or injured patients, or even to the intensive care unit. Diabetes, malignant disease, abdominal vasculitis, congestive heart failure, cholesterol embolization, and shock or cardiac arrest have been associated with acute acalculous cholecystitis. Children may also be affected, especially after a viral illness. The pathogenesis of acute acalculous cholecystitis is a paradigm of complexity. Ischemia and reperfusion injury, or the effects of eicosanoid proinflammatory mediators, appear to be the central mechanisms, but bile stasis, opioid therapy, positive-pressure ventilation, and total parenteral nutrition have all been implicated. Ultrasound of the gallbladder is the most accurate diagnostic modality in the critically ill patient, with gallbladder wall thickness of 3.5 mm or greater and pericholecystic fluid being the two most reliable criteria. The historical treatment of choice for acute acalculous cholecystitis has been cholecystectomy, but percutaneous cholecystostomy is now the mainstay of therapy, controlling the disease in about 85% of patients. Rapid improvement can be expected when the procedure is performed properly. The mortality rates (historically about 30%) for percutaneous and open cholecystostomy appear to be similar, reflecting the severity of illness, but improved resuscitation and critical care may portend a decreased risk of death. Interval cholecystectomy is usually not indicated after acute acalculous cholecystitis in survivors; if the absence of gallstones is confirmed and the precipitating disorder has been controlled, the cholecystostomy tube can be pulled out after the patient has recovered.     

Acute emphysematous cholecystitis. Report of twenty cases.

BACKGROUND/AIMS: Our aim is to present our experience with acute emphysematous cholecystitis (AEC), a severe variety of acute cholecystitis characterized by early gangrene and perforation of the gallbladder. METHODOLOGY: We reviewed the clinical records of 20 patients with AEC, analyzing age, sex, past medical history, symptoms, laboratory tests, X-rays, ultrasounds, operative and microbiological findings, morbidity and mortality. RESULTS: Our study included 13 men and 7 women (mean age 59 years). Associated factors were diabetes mellitus (11 cases) and gallstones (6 cases, 3 of them with common bile duct stones). Clinical symptom presentation included: right hypochondrial pain and fever in all cases, vomiting in 9, septic shock in 3, jaundice in 7, and peritonitis in 8. Hyperbilirubinemia was present in 7 cases. Plain abdominal X-rays or ultrasounds led to diagnosis in 95% of the cases. Surgical findings were AEC in all cases, pericholecystic abscess in 8, gallbladder necrosis in 7 and bile peritonitis in 3. C perfringens, E coli and B fragilis were the most frequent pathogens. Mortality rate was 25%, and morbidity 50%. CONCLUSIONS: AEC predominantly affects elderly diabetic men. Abdominal X-rays or ultrasounds are good diagnostic techniques, and emergency surgery is needed due to the high incidence of gangrene and perforation Despite all the efforts made, morbidity and mortality are still high.     

Percutaneous cholecystostomy in critically ill patients

Sixteen critically ill patients underwent percutaneous cholecystostomy because of suspected acute cholecystitis. The procedure was technically successful, although 11 of 16 patients died subsequently because of various complications of their underlying primary disorders. We reviewed this series to reassess the value of percutaneous cholecystostomy. Four of 11 patients with definite acute cholecystitis (group 1) were cured by this technique, but three required surgery because of gallbladder wall necrosis. Two of these were among four cases which had demonstrated pericholecystic fluid collections on computed tomography (CT) or ultrasound of the abdomen. There were also five patients (group 2) in whom acute cholecystitis or its relationship to patients' symptoms were not fully determined, and four of them did not improve after percutaneous cholecystostomy. We conclude that this technique has a lower success rate in critically ill patients than reported previously.     

Preoperative MRCP to detect choledocholithiasis in acute calculous cholecystitis

Purpose

There are risks of common bile duct (CBD) stones in acute cholecystitis, and there is a move among surgeons to identify choledocholithiasis before surgery. Magnetic resonance cholangiopancreaticography (MRCP) has the potential to accurately detect choledocholithiasis in patients with acute cholecystitis. The aim of this study was to evaluate the predictive values of MRCP and elevated biochemical predictors for choledocholithiasis in patients with acute cholecystitis.

Methods

Between September 2006 and August 2008, of 84 patients with acute cholecystitis based on the diagnosis criteria of the Tokyo guidelines, 57 had MRCP preoperatively. The predictive values of six biochemical predictors for choledocholithiasis were also evaluated.

Results

Of the 57 patients, seven (12.28%) had choledocholithiasis, of whom three had CBD stones in nondilated ducts. The smallest stone detected in a dilated CBD and nondilated duct was 3.19 and 4.55 mm in diameter, respectively. None of our patients whose MRCP showed a clear CBD returned with symptomatic choledocholithiasis during the follow-up period. All biochemical predictors and CBD diameter had limited positive predictive values.

Conclusions

Magnetic resonance cholangiopancreaticography is a reliable evaluation technique for the detection of choledocholithiasis. It reduces the misdiagnosis of retained choledocholithiasis with normal biochemical predictors and prevents the risk of overlooking choledocholithiasis. No single predictor or combined markers have been found to be reliable for including/excluding the presence of choledocholithiasis.     

Spontaneous gallbladder perforation, pericholecystic abscess and cholecystoduodenal fistula as the first manifestations of gallstone disease

BACKGROUND:Gallstone disease is common,and complications that are frequently encountered include acute cholecystitis and acute pancreatitis,but rarely gallbladder perforation. METHOD:Data were retrospectively collected from clinical case notes and a literature review is presented. RESULTS:A 72-year-old lady presented with spontaneous gallbladder perforation,pericholecystic abscess and cholecystoduodenal fistula as the first manifestations of gallstone disease.She was previously well and had no abdominal com...     

IMPACT OF ENDOSCOPIC TRANSPAPILLARY NASO‐GALLBLADDER DRAINAGE AFTER ENDOSCOPIC SPHINCTEROTOMY IN PATIENTS WITH ACUTE CHOLECYSTITIS AND CHOLEDOCHOLITHIASIS

Aim: To evaluate prospectively the efficacy of endoscopic transpapillary naso‐gallbladder drainage (ETGBD) after endoscopic sphincterotomy (ES) in patients with acute cholecystitis with choledocholithiasis. Patients: Twenty‐six patients with acute cholecystitis and choledocholithiasis, but without pericholecystic liver abscess, were evaluated. After ES and extraction of stones, ETGBD was performed immediately. Results: In 24 of the 26 patients with ES, complete bile duct clearance was achieved. In the other two cases treated with ES, stones could be completely removed in an additional session after ETGBD. ETGBD was successfully performed in 23 patients (88%). In three patients with unsuccessful ETGBD, a percutaneous cholecystostomy (PC) was performed. Of the 23 patients that underwent ETGBD, a positive clinical response at 72 h was seen in 22 (96%) patients. In one patient who did not show a clinical response at 72 h, catheter drainage was continued and a positive clinical response was seen 5 days after the procedure. In three patients treated with PC, a clinical response at 72 h was seen in all cases (100%). No major procedure‐related complications occurred. Conclusions: ETGBD after ES proved useful in the management of acute cholecystitis and choledocholithiasis.     

High b-value diffusion-weighted magnetic resonance imaging for gallbladder lesions: differentiation between benignity and malignancy

Background

Recently, the clinical application of diffusion-weighted magnetic resonance imaging (DWI) has been expanding to abdominal organs. However, only a few studies on gallbladder diseases have been published. The aim of this study was to evaluate the usefulness and limitations of high b-value DWI for gallbladder diseases.

Methods

A total of 153 patients (mean age 60 ± 15 years, 78 males) who had undergone DWI for evaluating gallbladder wall thickening or polypoid lesions were included in this study. Of these 153 patients, 36 had gallbladder cancer and 117 had benign gallbladder diseases (67 chronic cholecystitis, 44 adenomyomatosis, four cholesterol polyp, one gallbladder adenoma, and one xanthogranulomatous cholecystitis). We evaluated the positive signal rate with DWI and the apparent diffusion coefficient (ADC) value of each disease.

Results

The positive signal rate with DWI was significantly higher in gallbladder cancer (78 %) than in benign gallbladder diseases (22 %) (p < 0.001). The mean ADC value of gallbladder cancer was (1.83 ± 0.69) × 10^?3 mm²/s and that of benign gallbladder diseases was (2.60 ± 0.54) × 10^?3 mm²/s (p < 0.001). Benign gallbladder diseases with acute cholecystitis or a history of that had a higher positive signal rate with DWI (p < 0.001) and a lower ADC value (p = 0.018) than those without such conditions.

Conclusion

DWI can contribute to the improvement of the diagnostic capability for gallbladder wall thickening or polypoid lesions by compensating for weaknesses of other modalities by its many advantages, although cases with acute cholecystitis or such history sometimes show false-positive on DWI.     

Histological examination of frozen sections for patients with acute cholecystitis during cholecystectomy

BACKGROUND:Unexpected gallbladder cancer may present with acute cholecystitis-like manifestations.Some authors recommended that frozen section analysis should be performed during laparoscopic cholecystectomy for all cases of acute cholecystitis.Others advocate selective use of frozen section analysis based on gross examination of the specimen by the surgeon.The aim of the present study was to evaluate whether surgeons could effectively identify suspected gallbladder with macroscopic examination alone.If not,is routine frozen section analysis worth advocating?METHODS:A total of 1162 patients with acute cholecystitis who had undergone simple cholecystectomy in our hospital from February 2009 to February 2014 were enrolled in the study.The data of patients with acute cholecystitis especially those with concurrent gallbladder cancer in terms of clinical characteristics,operative records,frozen section diagnosis and histopathology reports were analyzed.RESULTS:Thirteen patients with acute cholecystitis were found to have concurrent gallbladder cancer,with an incidence of 1.1%in acute cholecystitis.Forty patients with acute cholecystitis were suspected to have gallbladder cancer by macroscopic examination and specimens were taken for frozen section analysis.Six patients with gallbladder cancer were correctly identified by macroscopic examination alone but 7patients with gallbladder cancer missed,including 3 patients with advanced cancer(2 T3 and 1 T2).Meanwhile,in 6 gallbladder cancer specimens sent for frozen section analysis,3 early gallbladder cancers(2 Tis and 1 T1a)were missed by frozen section analysis.However,the remaining 3 patients with advanced gallbladder cancers(2 T3 and 1 T2)were correctly diagnosed.CONCLUSIONS:The incidence of comorbidity of gallbladder cancer and acute cholecystitis is higher than that of non-acute cholecystitis.The accurate diagnosis of gallbladder cancer by surgeons is poor and frozen section analysis is necessary.     

无先天性胆管囊性扩张型的胰胆管汇流异常与胆胰疾病的关系

目的：研究无先天性胆管囊性扩张型的胰胆管汇流异常（APBJ）及其与与胆胰疾病的关系。方法：分析1995年1月－2002年1月间逆行胰胆管造影（ERCP）、术中胆道造影（IOC）、磁共振胰管造影（MRCP）等影像学检查的2150例胆胰疾病中的52例无先天性胆管囊性扩张型APBJ及其与胆胰疾病的关系。结果：本组APBJ的发生率为2．4％，APBJ的检查发现率为ERCP2．9％，IOC2．4％、MRCP2．0％，在52例无先天性胆管囊性扩张型APBJ中有P－C型（胰管注入胆总管）32例、C－P型（胆总管汇入胰管）20例。胆囊上皮增生的发生率为51．9％，胆囊结石的发生率为73．1％，胆囊息肉样病变的发生率为26．9％，急性胰腺炎的发生率为34．6％，结论：APBJ与胆囊疾病关系密切，无先天性胆管囊性扩张型APBJ的胆囊上皮增生和胆囊息肉样病变发生率高，是胆囊癌发生的一个高危因素，对此类型APBJ病人主张预防性胆囊切除，APBJ是胰腺炎发病的一个重要因素，C－P型APBJ的胰腺炎发生率高，在反复胰腺炎发作而无明显原因时，应考虑有APBJ的存在。     

磁共振胆胰管成像对老年性胆总管扩张患者诊断价值

目的老年性胆总管扩张患者磁共振胆胰管成像（magnetic resonance cholangiopancreatography，MRCP）的诊断和鉴别诊断价值评估。方法回顾性分析197例老年性胆总管扩张患者MRCP检查及临床诊断与治疗结果进行比较。结果MRCP诊断为胆总管下端结石68例，急性胆囊炎，胆囊结石伴胆总管扩张57例，胆囊切除术后改变38例，胆囊颈管结石22例，胆道系统肿瘤7例，胰腺占位性病变5例，诊断符合率99．5％结论MRCP在老年性胆总管扩张的病因诊断和鉴别诊断中有重要价值。