Review for 10.1186/1471-230X-11-84 (2011)

Reviewer's report
Title:Intrahepatic blood flow assessment by Doppler ultrasonography:
relationship among hepatic vein, portal vein, hepatic artery and portal pressure
intraoperatively measured in patients with portal hypertension
Version: 2Date:19 December 2010
Reviewer: Seyed-Mohammad Fereshtehnejad
Reviewer's report:
19 December 2010
Dear editor of BMC Gastroenterology;
I reviewed the manuscript titled: "Intrahepatic blood flow assessment by Doppler
ultrasonography: relationship among hepatic vein, portal vein, hepatic artery and
portal pressure intraoperatively measured in patients with portal hypertension".
It seems that the manuscript contains some interesting and new information for
both radiologists and gastroenterologists. However, in my opinion some major
revisions are needed. My recommendations and questions are listed as follow:
Abstract
• In addition to the patients, the presence of a control group must be also
mentioned in the "Methods" section of the abstract.
Introduction
• In regard to the focused subject of BMC Gastroenterology journal, it is better to
mention some evidences in relation with hepatic diseases as well as radiologic
aspects of this subject in the "Introduction" section of the manuscript.
Methods
• More detailed information of patients and control groups should be stated in the
"Patients" section of "Methods". This could be included patients diagnosis and
selection, full eligible criteria of both case and control groups, source of control
selection, sample size calculation, etc.
• Evaluating the factors which are considerably related to baseline characteristics
like age, gender, etc need to be matched between patient and control groups
regarding these potential confounding factors. Was it considered in this study? If
yes, please mention the details in the "Patients" section of "Methods".
• As some measurements are not performed in controls, it is recommended to
more clearly declare which indexes are measured in each groups of the study.
Results
• Please add the baseline characteristics of the control group to Table 1, and
compare the differences of these factors between two groups of the study.
• Please mention the measurement units wherever it is needed (e.g. line 13 of
"Results" section).
• How did the athors evaluate the confounding effects of some baseline
characteristics (e.g. patients' age) in the relationship found between HV
waveforms and PP? Or HAPI and HV waveforms? Are these variables
considered in linear regression models?
• It is recommended to add the boxplots for PVVel and HAPI of control group in
Figures 2 and 3, respectively; and state the P-value of comparisons with control
data as well.
• Although it is previously studied in other manuscripts, it is recommended to
evaluate the relationship between histopathological findings (e.g. severity of
cirrhosis and grade of fibrosis) and these radiologic indexes in the "Results"
section of the manuscript, too. It will help to better understanding of the
association between severity of liver disease and hepatic hemodynamic and
make it more useful for gastroenterologists.
Discussion
• How did the authors conclude that "Of these parameters, HAPI seemed more
sensitive to reflect abnormal HV waveforms."? Considering the statistical
approaches, receiver operating characteristics curve (ROC) analysis must be
performed to evaluated the diagnostic values (e.g. sensitivity) of different
continuous variables to predict a dichotomous outcome (e.g. normal vs.
abnormal HV waveform). However, it is recommended to perform ROC statistical
procedure in order to estimate and compare the diagnostic values of these
indexes to predict abnormal HV waveform or even high grade versus low grade
fibrosis. It is also of interest to derive the appropriate cutoff points for each
measurement as well.
• As it is declared within the limitations of current study, it is not ethical to rule out
possible liver abnormalities in control group by biopsy. Since it is known, normal
liver function test is not acceptable enough to evaluate some common conditions
like NAFLD. Therefore, was fatty infiltration evaluated in control group using
non-invasive methods such as ultrasonography of liver parenchyma?
Best regards
SM Fereshtehnejad M.D. M.P.H.
Level of interest: An article of importance in its field
Quality of written English: Needs some language corrections before being
published
Statistical review: Yes, and I have assessed the statistics in my report.
Declaration of competing interests:
I declare that I have no competing interests.