急性胰腺炎（AP）评分之 Balthazar CT 分级评分系统

优点：此系统将胰腺外侵犯与增强后未强化的胰腺坏死区结合起来（前提：增强CT被认为是诊断胰腺坏死的金标准）

急性胰腺炎分级

A级 胰腺正常，为0分
B级 胰腺局限性或弥漫性肿大（包括轮廓不规则、密度不均、胰管扩张、局限性积液），为1分
C级 除B级病变外，还有胰周炎性改变，为2分
D级 除胰腺病变外，胰腺有单发性积液区，为3分
E级 胰腺或胰周有2个或多个积液积气区，为4分

胰腺坏死程度

无坏死，为0分
坏死范围≦30%，为2分
坏死范围≦50%，为4分
坏死范围>50%，为6分

CT严重程度指数（CTSI）＝急性胰腺炎分级＋胰腺坏死程度
严重度分为三级：I级，0-3分；II级，4-6分；III级，7-10分，II级以上为重症。

下面来自eMedicine：http://www.emedicine.com/radio/topic521.htm

CECT can be used to assess the severity and estimate the prognosis of acute pancreatitis. Balthazar et al developed a grading system in which patients with acute pancreatitis are classified into 1 of the following 5 grades:

• Grade A - Normal-appearing pancreas
• Grade B - Focal or diffuse enlargement of the pancreas
• Grade C - Pancreatic gland abnormalities associated with peripancreatic fat infiltration
• Grade D - A single fluid collection
• Grade E - Two or more fluid collections

Patients with grades A and B pancreatitis have been shown to have mild uncomplicated clinical courses, while most complications of acute pancreatitis occur in patients with grades D and E.

Balthazar et al further constructed a CT severity index (CTSI) for acute pancreatitis that combines the grade of pancreatitis with the extent of pancreatic necrosis. The CTSI assigns points to patients according to their grade of acute pancreatitis as well as the degree of pancreatic necrosis. More points are given for a higher grade of pancreatitis and for more extensive necrosis. Patients with a CTSI of 0-3 had a mortality of 3% and a complication rate of 8%. Patients with a CTSI of 4-6 had a mortality rate of 6% and a complication rate of 35%. Patients with a CTSI of 7-10 had a 17% mortality rate and a 92% complication rate.

Grade of acute pancreatis and the points assigned per grade are as follows:

• Grade A - 0 points
• Grade B - 1 point
• Grade C - 2 points
• Grade D - 3 points
• Grade E - 4 points

Grade of necrosis and the points assigned per grade are as follows:

• None - 0 points
• Grade 0.33 - 2 points
• Grade 0.5 - 4 points
• Grade higher than 0.5 - 6 points

Degree of Confidence: In a prospective study of 202 patients, Clavien et al reported a 92% sensitivity and 100% specificity in diagnosing acute pancreatitis via CECT. Balthazar et al report an overall accuracy of 80-90% in the detection of pancreatic necrosis. Small areas of necrosis involving less than 30% of the pancreas can be missed. Nevertheless, the extent of pancreatic necrosis has been found to correlate well with operative findings and clinical severity. In a study by Block et al, the positive predictive value of CECT for pancreatic necrosis was found to be 92%.

False Positives/Negatives: The pancreas may appear normal in approximately 25% of patients with mild pancreatitis. In the acute phase of pancreatitis a small number of patients will have a false-positive diagnosis for necrosis due to massive interstitial edema and vasoconstriction of the vascular arcades. Repeat CT within a few days may show normal pancreatic enhancement.