Review for 10.1186/1471-230X-14-16 (2014)

Reviewer's report
Title:Detection of small ( < 2 cm) pancreatic adenocarcinoma and surrounding
parenchyma: correlations between enhancement patterns at triphasic MDCT and
histologic features.
Version: 2Date:17 September 2013
Reviewer: Maria Antonietta MD Mazzei
Reviewer's report:
Major comments
1) The manuscript is well structured and the question posed by the authors is
well defined.
DISCRETIONARY REVISIONS:
1. Histological evaluation “The surgical specimens of the
duodenal-cefalopancreatectomy or pancreatectomy were
examined for the PDA (n=38) and pancreatic parenchyma upstream (n=38) and
downstream (n=25) to the tumor”. It is not immediately clear why the histological
examinations are available in only 25 cases for downstream paranchima. Could
the Authors explain this point?
2. Multislice CT protocol: line 17, beam pitch instead of pitch;
3. Discussion: A lot of articles regarding the use of CT perfusion for detection of
PDA are available in recent literature. Could the authors introduce this point in
the section of discussion, making the limit of this technique regarding this
diagnosis clear? The following reference should be useful to the Authors.
Mazzei MA, Squitieri NC, Sani E, Guerrini S, Imbriaco G, Di Lucia D, Guasti A,
Mazzei FG, Volterrani L. Differences in perfusion CT parameter values with
commercial software upgrades: a preliminary report about algorithm consistency
and stability. Acta Radiol 2013; 54:805-11.
MINOR ESSENTIAL REVISIONS:
1. MATERIAL AND METHODS: Methods are appropriate and well described and
the data is sound.
Image Analysis: lines 23-24: “An attempt was made to maintain a constant ROI
area…” Please specify how the Authors attempted to maintain the same ROI
area: this is fundamental to avoid computing bias.
Image analysis: lines 32-35 “A positive difference of enhancement indicates that
the lesion is hyperdense compared with surrounding parenchyma and vice versa.
When the difference in attenuation between the lesion and parenchyma
upstream or downstream presents values <10 HU, the lesions not recognizable
(PDA so called “isodense”)”... It should be revised as follow..."A positive
difference of contrast enhancement indicates that the lesion is hyperdense
compared with surrounding parenchyma and vice versa. When the difference in
attenuation between the lesion and pancreatic parenchyma upstream or
downstream to the lesion presents values <10 HU, the lesions was defined as
unrecognizable (PDA so called “isodense”)”
4. Image analysis: lines 36-38: “After the assessment of PDA and pancreatic
parenchyma up-/downstream to the tumor attenuation, the time-density curves
(TDCs) of PDA and pancreatic parenchyma up-/downstream in each patient were
generated and categorized in three patterns” …It should be revised as
follow..."After the assessment of PDA and up-/downstream pancreatic
parenchyma to the tumor attenuation, the time-density curves (TDCs) of PDA
and up-/downstream pancreatic parenchyma in each patient were generated and
categorized in three patterns";
Please pay attention to this correction for the entire manuscript.
5. DISCUSSION: Discussion is well balanced and adequately supported by the
data.
“In our study, type 1 pattern (normal pancreas) was observed in downstream
pancreas (19/25 cases; 76%), type 2 pattern (mild chronic pancreatitis) was
observed in PDA (5/38 cases; 13,2%), in downstream (6/25 cases; 24%) and in
upstream pancreas (20/38 cases; 52,6%), and type 3 pattern (severe chronic
pancreatitis) was identified in PDA (33/38 cases; 86,8%) and in pancreas
upstream (18/38 cases; 47,4%). At qualitative analysis small PDA was isodense
to the pancreas upstream to the tumor on PPP in 10/38 (26.3%), on PVP in
12/38 (31.6%) and on DP in 22/38 cases (57.9%). At quantitative analysis
isoattenuating small PDA was observed in 7/38 (18.4%) on PPP, in 9/38 (23.7%)
on PVP and in 21/38 (55.3%) on DP and was related to a similar pattern (mild or
severe pancreatitis of upstream pancreas and mild and abundant fibrosis in
PDA).”
This part has also been reported in the results section; the Authors should extract
the essential useful data for the discussion to avoid repetitions.
6. STUDY LIMITATIONS: limitations of the work are clearly stated. Please
provide the exact number of histologically proven PDAs.
7. TABLE :
TABLE 1. Please include what value is reported in brackets in the legend.
TABLE 2. Please change the legend because it does not represent the value in
terms of percentage (that is in brackets) but in terms of ratio.
TABLE 3. OK
TABLE 4. Please include what value is reported in brackets in the legend.
DIAGRAM 1. OK
DIAGRAM 2. Please include the extent of “L/up” and “L/Down” in the legend
CAPTIONS FOR ILLUSTRATIONS: FIGURE 1. OK, FIGURE 2. 3rd phrase,
please replace “enhacment” with enhancement.
8. REFERENCES: The style and composition are well structured, they match the
Authors’ guidelines for references.
9. Statistical review: statistically sufficient
Level of interest: An article of outstanding merit and interest 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' below.