Perpetuation: A main portal vein (MPV) diameter >13 mm is "consistent with portal hypertension" (pHTN)This cutoff of 13 mm is based on weak literature (mainly from the 1980's), some of which did not include comparison values of normal patients
- One comparative study using ultrasound found (Radiology 1982; 142: 167-172):
- In 79 patients with pHTN
- 36 had a MPV diameter of <13 mm
- 33 had a MPV diameter >/= 13 mm
- The MPV was not visualized in 10 patients
- In the 45 control patients
- The MPV diameter was < 13 mm in 41 cases
- The MPV was not visualized in 4 patients.
More recent studies have found that there is no significant difference in MPV diameters when comparing patients without cirrhosis to patients with cirrhosis, and the normal MPV diameter is significantly larger than the 13 mm cutoff
- A study (Eur J Gastroenterol Hepatol 2004; 16:147-155) from King's College using ultrasound (49 controls and 14 cirrhotics) found:
- the average MPV diameters were 9.6 cm and 10.8 cm in patients without and with cirrhosis, respectively.
- A second study (JCAT 2008; 32: 198-203) from UCSF using CT (59 controls and 67 cirrhotics) found:
- The average MPV diameters were 14.5 cm and 14.8 cm in patients without and with cirrhosis, respectively.
- Using CT, the MPVs in healthy renal donor patients were measured before and after the administration of intravenous contrast, and in the axial and coronal planes (Abdom Radiol 2016; 41:1931-1936). This study found:
- The average MPV diameter was 15.5 +/- 1.9 mm
- This value was significantly different than 13 mm
- Post-contrast MPVs were 0.56 mm larger compared to non-contrast
- A positive correlation between BMI and height versus MPV diameter
- A MPV diameter of less than 1 cm is a highly sensitive (but not very specific) for MPV flow reversal in patients with cirrhosis