Characteristics of the imaging diagnosis of alveolar echinococcosis

Table 1 PNM status of the patients, n (%)[19]

PNM system for classification of human alveolar echinococcosis		Number of patients
P	Hepatic localization of the primary lesion
PX	Primary lesion cannot be assessed	-
P0	No detectable liver lesion	-
P1	Peripheral lesions without proximal vascular and/or biliary involvement	14 (22.9)
P2	Central lesions with proximal vascular and/or biliary involvement of one lobe	32 (52.4)
P3	Central lesions with hilar vascular and biliary involvement of both lobes and/or withinvolvement of two hepatic veins	11 (18)
P4	Any lesion with extension along the portal vein, inferior vena cava, or hepatic arteries and thebiliary tree	4 (6.5)
N	Extra hepatic involvement of neighboring organs or tissues
NX	Cannot be evaluated	-
N0	No regional involvement	55 (90.1)
N1	Regional involvement of contiguous organs or tissues	6 (9.8)
M	Absence or presence of distant metastases
MX	Not completely evaluated	-
M0	No metastasis	57 (93.4)
M1	Metastasis present	4 (6.5)