Review for 10.1186/1471-230X-13-53 (2013)

Reviewer's report
Title:Three-dimensional whole-liver perfusion MR imaging in patients with
hepatocellular carcinomas and colorectal hepatic metastases
Version: 2Date:29 July 2012
Reviewer: Orpheus Kolokythas
Reviewer's report:
General Comments:
1. This is a feasibility study for 3D-whole liver perfusion MRI. Since the goal is
feasibility of the method, the relatively low number of 26 patients is justified and
does not pose a real limitation of the study.
2. The comparison of the results of the parameters K trans and Ve for HCC
versus metastatic disease is interesting: while it is conceivable that K trans is
higher in HCC than in metastatic disease, the absence of a significant difference
between the two malignancies in Ve values, which are considered to reflect
tumor necrosis, is also interesting. The conclusion that this might be related to
comparable necrotic components in both tumor groups is also conceivable, but
remains an assumption, unless the authors can back up this conclusion by
observations of macroscopically identifiable necrotic tumor components on MRI.
A statement commenting on the presence of macroscopic tumor necrosis by
imaging or histopathologic criteria should therefore be made under "Discretionary
revisions".
3. The objective of the study is adequately addressed in the methods sections
and reflected in the results. However details are missing, please see #3 of "Major
Compulsory Revisions".
Major Compulsory Revisions
1. The manuscript demonstrates significant language deficiencies, making it
almost impossible at times to understand the message. Revision by a more
experienced English speaker is compulsory. Two examples in the "Methods":
"The first breath hold lasted one scan coincided with the beginning of contrast
material injection, to obtain an unenhanced baseline scan, and Three
subsequent breath holds lasted 18.5 seconds each for 5 scans every 8 seconds
at 16th second after the beginning of the contrast media injection."
Or: "MR data sets of all patients were sent to a separate workstation including a
commercially available software tool (Tissue 4D,Syngo MR B17,Siemens
Healthcare), which contains an algorithm for automated for the calculation of
perfusion parameter images." There are also spelling, and other editing errors.
While the bullet format is good, the writing style in the section "Data Analysis"
should be revised.
2. No information is given about the presence of hepatic cirrhosis. Hepatic
fibrosis and cirrhosis alter hepatic perfusion. Particularly patients with HCC often
may have underlying cirrhosis. To give the reader a better understanding of the
patient population, the authors should list the number of patients with cirrhosis
and assign them to the two groups of tumors.
3. The results section is too short and requires the inclusion of more data. The
reader would expect to see a list and analysis of
a) tumor size (min, max, mean tumor size of all tumor and also broken down in
HCC and metastases). Difference in size could potentially have an influence on
perfusion parameters, but this is unknown.
b) enhancement characteristsics (broken down in HCC and metastases: how
many HCC or metastases were hypervascular vs. hypovascular, how many had
"contrast washout" out vs. delayed enhancement etc?)
Minor Essential Revisions
1. spelling errors
2. Figure 2 showing the screenshot of the quantification tool should explain the
findings, so the reader has a better understanding of a) the diagnosis (HCC vs.
metastasis), the contrast phases selected, and meaning of the color coded
information on the color coded image and interpretation of the time-intentsity
curve given.
Discretionary Revisions
A statement commenting on the presence of macroscopic tumor necrosis in both
tumor groups HCC vs. metastases by imaging or histopathologic criteria should
be made (see comment above regarding "Ve").
Level of interest: An article whose findings are important to those with closely
related research interests
Quality of written English: Not suitable for publication unless extensively edited
Statistical review: No, the manuscript does not need to be seen by a
statistician.
Declaration of competing interests:
I declare that I have no competing interests.