This a manufactured 17 standard iron oxide based

This  works  aims  to
 assess  images
 obtained  with
 administration  of  açai
 juice  as  compared  to
 a manufactured

17                          standard   iron   oxide   based   contrast   employed   as 
 negative   oral   contrast   agents   in   Magnetic   Resonance

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18

19                          Cholangiopancreatography  (MRCP),   employing   qualitative   and   quantitative   evaluation.   The   research 
 was

20                          developed with 64 patients submitted to MRCP exams (on 2 days) in a clinic of Curitiba city (Brazil). On the 1st day,

21                          a manufactured
 iron oxide based contrast (A) was offered and on the 2nd  day, açai juice (contrast B) was given to

22

23                          patients. 2 radiologists (R1 and R2) evaluated the images, classifying them by a score (maximum of 4). In order to

24                          have a quantitative assessment, Image J free software was employed generating plots of gray levels against distance

25

26                          of a chosen area of the bile duct interest region. Evaluating images for contrast A, R1 furnished an average score of

27                          3.52 and R2 of 3.27. For contrast B, R1 provided 3.44 and R2 3.38. Both evaluators considered image quality with

28                          contrast A adequate for 62 (96.9%) patients. R1 considered adequate for 62 (96.9%) and R2 for 60 (93.8%) patients

29

30                          when using açai juice. By taking same images for all patients with Image J, a quantitative
 analysis was obtained,

31                          resulting  correlation
 coefficient  of 0.986  between  average  curves
 of contrasts
 A and B.   Thus,  açai
 juice
 is an

32                          alternative as contrast agent in MRCP, since a standardized protocol is implemented.
 Image J was employed as a

33

34                          new method for quantitative investigation of image quality, presenting good agreement with medical opinion.

35

36                          Key words:
 Açai  contrast
 agent;
 iron
 oxide  contrast;  magnetic  resonance  cholangiopancreatography;  image

37

38                          quality; image J.

39

40

41                          INTRODUCTION

42                          Magnetic  Resonance  Cholangiopancreatography (MRCP)  exams
 make  use
 of
 a
 negative
 contrast  to

43                          identify and visualize organs such as pancreas and gallbladder. In the images, contrast agents can avoid

45

 

44                          the overlapping  of these organs 1. The procedure is useful for detection  of pancreatitis,
 cholelithiasis,

46                          biliary sludge, pseudo pancreatic cysts, tumors and others. Images acquired by magnetic resonance with

47                          natural contrasts are very similar to those acquired with manufactured ones, according to previous work

48                          done by other authors 2.

49                          For a juice to be effective as contrast agent in MRCP exams, some features are required 3, besides acting

50                          to reduce
 signal
 intensity  from the stomach  and duodenum
 and,  improving
 bile duct
 and gallbladder

51                          views. Although there are papers about the use of juices as MRCP contrast agents 4, it was not found

52                          publications about standardization procedure and administration protocol of the juices 5, 6.

53                          Image evaluation is achieved from several ways in clinics and hospitals by means of medical analysis or

54                          using some computational tool 7, 8, 9. These can help to identify lesions, tumors or some kind of alteration

55                          of  the  organ
 or
 tissue
 being
 examined.
 Image
 evaluation
 can  present
 inherent
 limitation
 due
 to  the

57

 

56                          technique employed or analysis made by different personnel and equipment.

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5                            Since there is a great amount of subjectivity on the assessment of the acquired images by medical teams,

6                            depending
 on the previous  experience
 of each evaluator,
 there is an opportunity
 to explore the use of

7                            Image J free software 10  in order to produce a new quantitative analysis of the images and to compare

8                            them to medical evaluation. Thus, the main objective of this study was to assess quality of MRCP images,

9                            obtained with the administration of açai juice and a manufactured iron oxide based contrast employed as

10                          negative oral contrast agents, by means of medical evaluation and with the use of Image J software 10.

11

12

13                          MATERIALS
AND METHODS

14                          Contrast agents

15

16                          Considering
 its use on previous works, a natural juice obtained from açai (Euterpe oleracea) pulp was

17                          employed as contrast agent, containing approximately 36 grams of carbohydrates per 100g, corresponding

18                          to the amount of sugar in the fruit 11. The manufactured
 iron oxide based contrast was obtained from

19                          Guerbet Ltda and used as specified for MCRP exams.

20

21                          MRCP exam protocol

22

23                          As patients
 would  need
 a medical
 report,  the 
exam  was
 started
 (first  day)  after  the ingestion  of the

24                          manufactured
 iron oxide based contrast (referred as A) with the sequence of full abdomen, followed by

25                          MRCP. On the second day, after the ingestion of açai juice (referred as contrast B), the MRCP sequence

26                          was  also
 performed.
 Doctors  supported  the  patients  in
 the  days
 of
 exams,  but  the  type  of
 contrast

27                          administered each day was kept secret.
 Thus, the study was double-blind and prospective 12.

28

29                          The images were acquired with a 1.5T MRI system from General Electric Company (GE), model HDXT

30                          with 12 channels,  GE Healthcare
 Advantage  workstation  running Centricity  DICOM
 (Digital  Imaging

31                          and Communications in Medicine) Viewer version 3.0 software, and were saved in the filing system and

32                          communicating images (PACS-Picture Archiving and Communication System) 13,
in a clinic of Curitiba

33                          city (Brazil).  The usual MRCP acquisition  protocol  was used: localizer  (LOC) in 3 orthogonal  planes

34                          (PL) following single-shot (SS), fast spin echo (FSE) in apnea (LOC 3 PL SSFSE Apnea); radial colangio

35                          14 and axial lava T1 without fat 15 for the two days of exams.

36

37                          Patient selection

38

39                          The selection of patients was made at the Clinics Hospital of Parana Federal University (UFPR), which

40                          receives patients from the metropolitan
 region of Curitiba city (via Health Units). The clinical research

41                          was  developed  during
 a period  of
 6 months,
 in the  outpatient  clinics
 of
 non-alcoholic  esteatopathy,

42                          alcoholic
 liver  disease  and  fat  and
 biliary
 routes  diseases.
 The  study  was
 approved
 by  the
 Ethics

43                          Committee of Federal University of Technology-Paraná (UTFPR) by number 02.520.512.0.00005547  and

44                          a free and informed consent form (ICF) was released. Patients who agreed to participate received the ICF

45                          and appropriate guidance on the MRI examination.

46

47                          For patient preparation,
 it was determined
 3 hours of absolute fast. On the first day, when the patient

48                          arrived at the clinic, he/she was directed to the preparation room, the fasting time was confirmed and the

49                          manufactured
 contrast (A) was fractionated in 2 doses of 100 mL, one dose was given after the patient

50                          responded   the   anamnesis,   and 
 another   was   given   10 
 minutes   later.   The   anamnesis 
 contained

51                          anthropometric data, history of allergy, use of medicines, pre-existing diseases (as diabetes and hepatitis),

52                          surgeries, etc. In case of a diabetic patient, glucose measurement in blood was performed before and after

53                          ingestion of contrasts.  On the second day, the procedure was similar, only changing the contrast, i. e.,

54                          administration of açai juice (B) in 2 doses of 100 mL was started.

55

56                          Patients who participated met the following criteria: age between 18 and 80 years for both genders, need

57                          to perform exams of MRCP and present pancreaticobiliary
 disease and/or alteration in liver ducts 16, 17

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5                            being
 in
 treatment  or  follow-up
 in
 the
 referred  hospital  and,
 ingest  the
 contrast
 agents
 orally
 and

6                            accomplish  fasting  of 3 hours  in the 2 days of the exams.
 Also,  patients  should
 lie down,
 not have

7                            claustrophobia nor hearing difficulties.

8

9                            Exclusion  criteria
 involved
 patients
 who  could  not  ingest  juice  and/or  contrast  agent,  or
 had  some

10                          difficulty  as: not being able to perform fasting, making use of devices such as pacemakers,  aneurysm

11                          clips, stents,  intraocular
 foreign  bodies,
 cochlear  implants,  prosthetic/  pins in any region  of the body

12                          which could cause artifacts  18. Also, exclusion criteria included pregnancy or suspected pregnancy.

13

14                          Medical images analysis

15

For

 

16                          For the analysis of images, there was the collaboration
 of 2 radiologists
 identified as R1 and R2, both

17                          with large experience in image diagnosis of more than 13 years.

18

19                          To analyze the effects of contrasts, scores 1-4 were used, having as reference the action of the contrast in

20                          places where it must make effect (stomach and duodenum). Score 1 means that there is a hyper intensity

21                          of  the  stomach  and
 duodenum
 signals,
 thus  it  is  not  possible  to
 evaluate  these
 structures.  Score
 2:

Review

 

22                          evaluation takes place partly when it is possible to visualize the structures. Score 3: the hyper intensity of

23                          the signal does not hinder the analysis of structures. Score 4: there is no signal hyper intensity between

24                          the stomach and duodenum, which makes clearer the MRCP exam 8.

25                          The evaluation
 of the image quality by doctors followed  the filling of a patient individual  form which

26                          contained:
 image
 quality
 classification  for contrasts  A and B as excellent,  good, fair and poor; if the

27                          acquired  image for contrasts A and B could replace each other; and if the contrasts were suitable and

28                          efficient for issuing a medical report 19.

29                          Also,  a  new
 quantitative
 evaluation
 method  based
 on
 Image
 J
 free
 software,
 16-bits
 version,  was

30                          employed   9  and it can furnish the intensity of pixels against distance of a chosen area of an image. By

31                          taking a section of interest from the image, one can limit the anatomical  region of the structure to be

32                          analyzed.
 After, the selected
 area (with x and y values)  is transferred
 to an Excel®
 file and a plot is

33                          produced with gray levels (pixel intensities) against distance (width of the bile duct region for this study)

34                          in mm 20.

35

36

37                          Statistical analysis

38

39                          Data analysis of patients was performed with the items in the anamnesis and medical evaluations, in order

40                          to assist in verifying the behavior of the variables 21. Subsequently, it was evaluated the concordance of

41                          responses of doctors through Kappa 22 statistics, aimed at testing the degree of concordance (reliability

42                          and precision), and to assess the values obtained. If ? 0.75, it indicates an excellent result. Values ? 0.40

43                          are considered low or if they become between 0.40 and 0.75 are of median concordance 23.