Utility of Diffusion-weighted MR Imaging in Guiding Selective Percutaneous Drainage of Postoperative Intra-abdominal Abscesses After Colorectal Resection
Phase: NA
Conditions: DWM
Sponsor: University of Chicago

Page 1 of 19                                                       Confidential                              IRB Approval Date: Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
 
PROTOCOL TITLE:  
Utility of diffusion-weighted MR imaging in guiding selective percutaneous drainage of 
postoperative intra-abdominal abscesses after colorectal resection 
 
 
PI: 
Lisa M. Cannon MD Department of Surgery 
Principal Investigator 
 
CO-I(S): 
Neil Hyman MD 
Department of Surgery 
Co-Investigator 
Aytekin Oto MD 
Department of Radiology 
Co-Investigator 
Melvy Mathew MD Department of Radiology 
Co-Investigator 
 
FUNDING:  
Internal:  Department of Radiology Magnetic Resonance Imaging Research Center 
(MRIRC) specifically for 20 hours of cost-free MRI scans at the MRIRC 
 
SPONSOR:  
PI (internal) 
 
TYPE OF RESEARCH:   
Prospective cohort  
 
INTERVENTION:  
Diffusion-weighted magnetic resonance scan (DW-MRI) 
 
MANUFACTURER OF INTERVENTION: 
N/A 
 
IND OR IDE #: 
N/A 
 
NAME OF PERSON WHO HOLDS IND OR IDE: 
N/A 
 
PROTOCOL VERSION: 
1.2 
 
PROTOCOL VERSION DATE: 
APRIL 13, 2017 
 
 
 
 

Page 2 of 19                                                       Confidential                              IRB Approval Date: Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
 
 
 
 
TABLE OF CONTENTS                                                                                                                           PAGE 
 
1. INTRODUCTION …………………………………………………………………. 
A. BACKGROUND AND RATIONALE…………………………………….. 
B. OBJECTIVES ………………………………………………………… 
2. STUDY DESIGN………………………………………………………………….  
3. SUBJECT SELECTION AND WITHDRAWAL……………………………………….  
4. STUDY DRUG/DEVICE (AS APPLICABLE)………………………………………… 
5. STUDY PROCEDURES ……………………………………………………………. 
6. STATISTICAL PLAN ……………………………………………………………… 
7. RISKS AND BENEFITS……………………………………………………………. 
8. SAFETY AND ADVERSE EVENTS …………………………………………………. 
9. DATA HANDLING AND RECORD KEEPING ……………………………………….. 
10. STUDY MONITORING, AUDITING AND INSPECTION………………………………. 
11. FINANCIAL CONSIDERATIONS……………………………………………………. 
12. ETHICAL CONSIDERATIONS ……………………………………………………... 
13. CONFLICT OF INTEREST …………………………………………………………. 
14. PUBLICATION PLAN ……………………………………………………………... 
15. REFERENCES …………………………………………………………………….. 
16. APPENDIXES ……………………………………………………………………... 
             A.  INFORMED CONSENT FORM ………………………………………… 
             B.  SCHEDULE OF EVENTS (SCHEMA) …………………………………….. 
             C.  DATA SAFETY MONITORING PLAN ………………………………………. 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

Page 3 of 19                                                       Confidential                              IRB Approval Date: Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
 
 
 
 
    . 
STUDY SUMMARY 
TITLE  
Utility of diffusion-weighted MR imaging in guiding 
selective percutaneous drainage of postoperative intra-
abdominal abscesses after colorectal resection 
SHORT TITLE 
MRI for post-operative abscess 
PROTOCOL NUMBER  
 
PHASE 
N/A 
METHODOLOGY 
Prospective cohort 
STUDY DURATION  
12-15 months (2016-2017) 
STUDY CENTER(S) 
Single-Center (UCMC) 
OBJECTIVES 
Objective 1.  To devise a limited DW-MRI protocol for 
evaluation of post-operative intra-abdominal 
collections  
Objective 2. To compare and determine best DW-MRI 
metrics for differentiation of sterile and infected intra-
abdominal fluid collections in the post-operative 
setting.  
Objective 3.  To construct a protocol using diffusion-
weighted MR imaging to guide selective percutaneous 
drainage of post-operative intra-abdominal abscesses 
after colorectal resection, and prevent drainage of 
sterile collections.   
NUMBER OF SUBJECTS  
20 (anticipated) 
DIAGNOSIS AND MAIN 
INCLUSION CRITERIA 
Adult patients who have undergone a colon or rectal 
resection at UCM and have developed a CT-proven 
abdominopelvic fluid collection > 3 cm in average 
diameter, for which the surgeon determines 
percutaneous drainage is indicated, will be eligible for 
inclusion in the study.   
STUDY PRODUCT, DOSE, 
ROUTE, REGIMEN  
DW-MRI acquisition:  Each exam will be limited to 
the collection that was already detected and localized 
by CT. Each exam will include a breath-hold T2-
SSFSE, T1-w GRE and DWI sequence. Total scanner 

Page 4 of 19                                                       Confidential                              IRB Approval Date: Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
time per patient is expected to be under 30 minutes. 
DURATION OF 
ADMINISTRATION  
N/A 
REFERENCE THERAPY  
N/A 
STATISTICAL METHODOLOGY  
Sensitivity and specificity of each review session for 
each radiologist will be calculated. McNemar’s test 
will be used for multiple comparisons of sensitivity of 
different review sessions. Confidence score of each 
review session will be compared using Wilcoxon-
signed rank test. Two-tailed Student’s t test will be 
used for comparison of ADC values. Simple κ 
coefficients will be used to assess interobserver 
agreement for confidence score and ADC 
measurements. An ROC curve will be constructed for 
ADC values, and area under the curve measured the 
overall ability of ADC in differentiation of abscess 
from non-infected collections.  
 
LIST OF ABBREVIATIONS 
 
ADC  
 
Apparent diffusion coefficient 
CT 
 
 
Computed tomography 
DWI  
 
Diffusion-weighted Imaging 
DW-MRI 
 
Diffusion-weighted magnetic resonance image 
GRE  
 
Gradient echo 
IAA 
 
 
Intra-abdominal abscess 
IV 
 
 
Intravenous 
kHz 
 
 
Kilohertz 
MRI 
 
 
Magnetic resonance image 
MRIRC 
 
MRI research center 
NEX  
 
Number of excitations 
PO 
 
 
Per oral 
 
ROI   
 
Region of Interest 
SENSE 
 
Sensitivity encoding 
SSFSE  
 
Single shot fast spin echo 
TE 
 
 
Echo time 
TR 
 
 
Repetition Time 
UCMC 
 
University of Chicago Medical Center 
UC 
 
 
University of Chicago 
 
 
 
 

Page 5 of 19                                                       Confidential                              IRB Approval Date: Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
 
 
 
 
 
1.  INTRODUCTION  
A. BACKGROUND AND RATIONALE 
Describe the following in detail: 
a) Background— Intra-abdominal abscesses are a known complication after colon 
and rectal resection.   Percutaneous drainage, as compared to surgical drainage, 
has been a mark of great progress in the management of post-operative intra-
abdominal abscesses.   However, increased use of cross sectional imaging with 
computed tomography (CT) as well as improved resolution of these images had 
led to identification of fluid collections of unclear clinical significance 
(Sarkissian).  Both clinical and radiologic assessment is necessary to objectively 
determine who will require drainage.  Percutaneous drainage is not without risk, 
and these interventions can prolong hospital stay, result in further imaging, 
increase need for homecare, and cause patient discomfort.  Within the subset of 
patients who ultimately undergo percutaneous aspiration and drainage, there is a 
subset with smaller abscesses who would have resolved spontaneously, and a 
subset who are found to have sterile collections, both representing unique 
overtreatment groups.  Current radiologic criteria felt to be selective for abscesses 
(i.e. rim-enhancement on CT) results in aspiration of sterile collections in up to 
40% of cases (Sarkissian).  
b) Disease and current understanding of disease— Percutaneous drainage of 
intra-abdominal abscesses occurring as a complication of colon and rectal 
resection has been a major advance in the management of surgical patients.  
Proper patient selection is critical for safe and effective management in this 
population.  Almost ¾ of patients undergoing CT scan after colorectal resection 
due to clinical suspicion of intrabdominal process will have at least one fluid 
collection identified.  These collections can represent a spectrum of clinical 
entities and there is not a consensus on the most effective management of these 
collections or even the definition of abscess.  Currently, reliance on radiologic 
criteria in isolation can lead to overuse of interventional procedures.  For 
example, 40% of rim-enhancing collections are sterile on aspiration.  The 
surgeons’ clinical suspicion for abscess and radiologic proximity to an 
anastomosis are the only criteria that are useful in predicting abscess versus sterile 
collection (Sarkissian).   A further consideration is the natural history of these 
abscesses.    Studies in the diverticulitis literature have demonstrated that 
abscesses less than 3 cm in greatest dimension are successfully managed with 
antibiotics alone, while abscesses greater than 6.5 cm are likely to require 
intervention.  However, this leaves a great number of abscesses between 3 cm and 
6.5 cm that fall into uncertain grounds (Oto, Kumar). In contrast to diverticulitis, 
where it can be reasonably inferred that an associated abdominopelvic collection 
is indeed and abscess, management of fluid collections identified post-operatively 

Page 6 of 19                                                       Confidential                              IRB Approval Date: Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
and determination of who will benefit from drainage is less clear.  A novel 
radiologic technique with high discrimination between sterile and infected 
collection would be of great clinical utility in the post-operative management of 
fluid collections after colorectal resection. 
c) Past research and/or preclinical data—Oto et. al. have identified a novel 
method using diffusion weighted magnetic resonance imaging (DW-MRI) of 
abdominopelvic collections that can perfectly discriminate abscesses from ascites 
with a threshold apparent diffusion coefficient (ADC) of 2.0 x 10-3 mm2/s (i).  It is 
important to note this study did not include collections identified in the post-
operative setting; it is unclear whether inflammatory fluid or presence of blood 
may diminish this discrimination.  If the discriminatory capacity is not 
diminished, then clearly DW-MRI has great potential within the diagnosis and 
treatment of post-operative abscess formation in colon and rectal resection. 
d) Rationale for conducting this research— Further investigation is required in 
order to determine whether DW-MRI is applicable in the evaluation of post-
operative collections, and whether utilization of DW-MRI can enhance 
application of percutaneous drainage and prevent unnecessary drainage. DW-MRI 
is well established in the identification and management of brain abscesses.   Oto 
et. al. have already demonstrated the utility of DW-MRI in discriminating 
abdominopelvic abscess from ascites. They compared ADC values of abscess and 
non-infected ascites in 58 patients.  Compared to T2-weighted images alone, 
addition of DW-MRI images allowed for nearly 100% detection of abscesses.   
Further, a cutoff ADC value of 2.0 x 10-3 mm2/s allows for perfect discrimination 
between abscess and non-infected ascites (Oto), thereby increasing the abscess 
detection rate (Fig. 1 (Fig . 7 from Oto et. al.)) and potentially minimizing 
unnecessary percutaneous aspiration or drainage. 
e) Dose rationale and risks/benefits (as applicable) – Not applicable 
f) Rationale for research design and population— The novelty of the proposed 
research project is that it seeks to broaden applicability of a proven but rarely used 
method, DW-MRI, to discriminate sterile or benign from infected abdominopelvic 
fluid collections, in order to enhance the utilization of percutaneous drainage in 
the post-operative setting after colorectal resection (Oto).   Ability to streamline a 
limited MRI protocol to efficiently obtain diffusion weighted imaging of the 
abdominal cavity will be key to applying this methodology into daily practice.  
Secondly, it is not known whether DW-MRI can effectively discriminate 
specifically post-operative sterile collections from abscesses.  This is one of the 
primary aims of this pilot study and will be used to generate hypothesis for a full-
scale study.   
 
B.  OBJECTIVES  
a) Hypothesis- DW-MRI is effective in discriminating sterile from benign 
abdominopelvic collections in the post-operative setting after colon or rectal 
resection with a high degree of discrimination using a defined apparent diffusion 
coefficient threshold. 
b) Describe in detail the study objectives, including primary and secondary 

Page 7 of 19                                                       Confidential                              IRB Approval Date: Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
a. Objective 1.  To devise a limited abdominal diffusion-weighed imaging 
protocol for evaluation of intra-abdominal collections in the post-operative 
setting.  
b. Objective 2. To identify the DW-MRI characteristics of infected and 
sterile intra-abdominal fluid collections in the post-operative setting after 
colon and rectal resection, and compare and determine best DW-MRI 
metrics for their differentiation.  
c. Objective 3.  To construct and demonstrate safety and feasibility of a 
protocol using diffusion-weighted MR imaging to guide selective 
percutaneous drainage of post-operative intra-abdominal abscesses after 
colorectal resection, and prevent drainage of sterile collections 
 
2.  STUDY DESIGN  
Describe the following in detail: 
a) Type of study & characteristics of this type of research: Prospective cohort 
b) Duration of study:  12-14 months 
c) Schedule of events:   
a. Clinical schedule: Adult patients who have undergone a colon or rectal 
resection at the University of Chicago Medicine and have developed a CT-
proven abdominopelvic fluid collection > 3 cm in average diameter, whom 
the surgeon has determined using traditional clinical and radiologic factors 
to be a candidate for percutaneous drainage, will be eligible for inclusion 
in the study.  (Fig. 2) These patients will undergo DW-MRI (see Objective 
1), and then be taken directly to the interventional radiology suite for 
drainage. Fluid will be sent for culture and gram stain.  In addition, the 
interventional radiology team will qualify the fluid in their notation as 
purulent, turbid/murky, serous, serosanguinous, sanguinous, bilious, or 
feculent.   In the event a patient otherwise meets criteria but the surgeon 
has determined that percutaneous drainage is not indicated, they will not 
be eligible for inclusion in the study.  If, due to nonresolution or 
worsening clinical status, the surgeon later decides that percutaneous 
drainage is appropriate, that patient will only then become eligible for the 
study.   
b. MRI acquisition:  MR imaging will be performed on a 3-T (Ingenia, 
Philips Healthcare) MR scanner with eight-channel-phased array body 
coil. MR imaging protocol will consist of axial and coronal T2-weighted 
single-shot fast spin echo sequences (TR, infinite; TE, 90 ms; 
matrix = 256 × 256; slice thickness = 6 mm; gap = 0 mm), an axial 
diffusion-weighted single-shot echo-planar sequence (free breathing with 
respiratory gating, TR/TE = 3,000–10,000/70–80, b factors 0, 100, 500, 
800, 1200 mm2/s, field of view = 32–50 cm, receiver 
bandwidth = 64 kHz, four signals acquired, section thickness = 5 mm, 
section interval = 7 mm, and acquisition time = 4–6 min) and a T1-
weighted three-dimensional gradient echo with fat suppression sequence 
(TR/TE = 4.2–4.6/2.0–2.3 ms, flip angle = 12–20°, matrix = 320 × 192, 

Page 8 of 19                                                       Confidential                              IRB Approval Date: Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
field of view = 30–38 cm, receiver bandwidth = 64 kHz, a parallel 
imaging reduction factor of 2, one signal acquired, section 
thickness = 5 mm, section interval = 2.5 mm) . These images will be 
obtained through the known location of the abscess based on previous CT 
examination. The total duration of MR scan time will be 25 minutes or 
under.  We will optimize our protocol by scanning two volunteers and test 
different SENSE, TR/TE and NEX parameters for an optimum protocol. 
 
d) Summary of sequence and duration of all study periods: The project duration 
is estimated at one year.  Based on the pilot data, the investigators will commit to 
submitting a full grant application within 3 months of completing the pilot data 
project.   
a. Month 1 – 9:  Patient accrual:  The Section of Colon and Rectal Surgery 
is committed to recruiting twenty (20) patients within this timeframe who 
have undergone colon or rectal resection including appendectomy and 
who through usual clinical processes have undergone cross-sectional 
imaging in the from of CT, with a discrete abdominopelvic abscess >3 cm 
in average diameter identified.   The patients will then be put through the 
pilot protocol as above (see Objective 3 and Fig. 2).   
b. Month 10-12:  Data analysis and assessment:  
i. Objective 1: The protocol will be validated for efficacy and cost, 
with the primary endpoint being ability to report an ADC value for 
a collection identified on prior CT through use of the DW-MRI 
protocol.   
ii. Objective 2: DW-MRI readings will be analyzed and ADC values 
will be compared and validated in an attempt to report a threshold 
ADC that reliably discriminates sterile and infected post-operative 
fluid collections.   
 
iii. Objective 3: Determine the effect size from utilization of DW-MRI 
(defined as a change in management decision to pursue drainage or 
hold on drainage)  
iv. Global Assessment:  Determine whether the outcome measures are 
appropriate, reliable, and feasible.  Finalize eligibility criteria for a 
larger study.  Generate hypothesis and determine sample size 
calculation for larger study.   
c. The investigator team will meet at 2-month intervals for a research in 
progress meeting to discuss accrual logistics and problem areas in order to 
fine tune the study protocol, and identify key parameters that will require 
adjustment prior to submission of a full grant application.  
e) Discuss randomization processes and use of controls or placebos, as 
applicable: Not applicable 
f) Primary and secondary endpoints:  
a. Primary output measures are ADC threshold to discriminate sterile from 
infected post-operative fluid collections 
g) Primary safety endpoints (must be measurable): Not applicable 

Page 9 of 19                                                       Confidential                              IRB Approval Date: Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
h) Rationale for study design:  The results of this pilot trial will form the basis of 
the R21 grant that our team is planning to submit in 2018. The data will help us to 
identify potential limitations of DWI in differentiation of abscess from non-
infected collections allow us to determine the appropriate cohort size for the NIH 
grant. Based on the correlation with DWI and clinical data, we will explore and 
suggest novel acquisition and analysis methods for quantitative DWI.  Each exam 
will be limited to the collection that was already detected and localized by CT. 
Each exam will include a breath-hold T2-SSFSE, T1-w GRE and DWI sequence. 
Total scanner time per patient is expected to be under 30 minutes.  
 
3.  SUBJECT SELECTION AND WITHDRAWAL  
a) Number of subjects:  20 
b) Gender of subjects: Any (goal is consecutive recruitment) 
c) Age of subjects: Adult 
d) Racial and Ethnic Origin:  Any (goal is consecutive recruitment) 
e) Inclusion Criteria:  
i. Adult (18 years or older) patients able to participate in the consent 
process 
ii. Have undergone colon or rectal resection within 30 days 
iii. CT-proven abdominopelvic fluid collection > 3 cm in average 
diameter 
iv. Surgeon has determined patient is clinically stable for 
unaccompanied transport to the MRIRC for image acquisition 
f) Exclusion Criteria: 
i. Contraindication to MRI (eg. Implant or other medical device) 
ii. Pregnant women, prisoners, and cognitively impaired persons  
iii. Claustrophobia preventing MRI acquisition 
iv. Not clinically stable to be transported unaccompanied to the 
MRIRC for image acquisition 
v. MRI acquisition will delay percutaneous drainage 
g) Vulnerable Subjects/Subject Capacity to provide consent:  Otherwise eligible 
subjects must retain capacity to consent to DW-MRI in order to be considered for 
the study.   
h) Location where research is to be conducted (building, floor, clinic/suite 
number): CUMC and the MRIRC 
i) Describe how subject’s primary treating physician will be notified of, and if 
appropriate, involved in the proposed research:  All UCMC surgical faculty 
who perform colon or rectal resection will be briefed on the study details. The 
surgeon study team will not have direct involvement in DW-MRI acquisition and 
image analysis.  The radiology study team will not have direct involvement in 
clinical care or clinical decision-making.   
j) As applicable, the coordination of any interdepartmental faculty, and where 
necessary, the inclusion of those faculty as participants:  All UCMC surgical 
faculty who perform colon or rectal resection will be briefed on the study details.  
The surgeon study team will not have direct involvement in DW-MRI acquisition 

Page 10 of 19                                                       Confidential                              IRB Approval Date: 
Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
and image analysis.  The radiology study team will not have direct involvement in 
clinical care or clinical decision-making.   
k) Method of subject identification and recruitment.  Adult patients who have 
undergone a colon or rectal resection at the University of Chicago Medicine 
within 30 days and have developed a CT-proven abdominopelvic fluid collection 
> 3 cm in average diameter, for which the surgeon determines based on best 
clinical practice that percutaneous drainage is indicated, will be eligible for 
inclusion in the study.   These patients will be reasonably on the colon and rectal 
surgery census, the surgical oncology patient census, or the resident acute care 
surgery census or in any of these complimentary ambulatory settings.  In the event 
a patient otherwise meets criteria but the surgeon has determined that 
percutaneous drainage is not indicated, they will not be eligible for inclusion in 
the study.  If, due to nonresolution or worsening clinical status, the surgeon later 
decides that percutaneous drainage is appropriate, that patient will only then 
become eligible for the study.   
l) Describe plans for remuneration to subject, as applicable: N/A  
m) Informed consent process 
Click here for an Informed Consent Checklist template 
n) Waiver of consent/waiver of authorization (as applicable): N/A 
o) Method of withdrawing subjects following completion of study: N/A – single 
point intervention (DW-MRI acquisition) 
p) Method of withdrawing subjects before completion (i.e., early termination):  
i. In the event that a subject consents for the study and only after this 
discloses extreme claustrophobia or metal implant which would 
preclude them from DW-MRI, this will be considered a screening 
failure and these patients will not be included on any analysis.     
ii. If the subject’s clinical status changes after initial screening such 
that they are no longer safe for transport to the MRIRC for image 
acquisition, or if it is the case that MRI acquisition will actually 
delay percutaneous drainage, the subject will be considered a 
screening failure and will not be included in the analysis.   
q) Method of collecting data and follow-up on subjects who have been 
withdrawn:  N/A 
 
5.  STUDY PROCEDURES 
a) Please see patient flow (Figure 2) as well as study design.   
b) This is a single point intervention (DW-MRI acquisition) within the context of a 
usual clinical care pathway.  The results of the DW-MRI will not be utilized for 
clinical decision making for the subjects in the study.   Primary output measures 
are ADC threshold to discriminate sterile from infected post-operative fluid 
collections which may be used to guide a larger prospective study.   
c) Labs, diagnostic testing, post-operative visits, and further intervention will be at 
the discretion of the surgeon based on usual best clinical care and not directly 
born of the study intervention (i.e. not research related).   
d) Methods and procedures:  See ‘MRI acquisition’ above under Study Design.  

Page 11 of 19                                                       Confidential                              IRB Approval Date: 
Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
e) Scales/assessments: None 
f) Examinations: None related to this single-point intervention 
g) Questionnaires: None 
h) Labs to be conducted: None related to this single-point intervention 
i) Plan for unscheduled visits: None related to this single-point intervention 
j) Contact between study visits:  None specifically research related.  Patients will 
undergo usual post-operative care.   
a) Future contact regarding research studies: None specifically research related.  
Patients will undergo a routing post-operative visit or visits at the discretion of 
their treating surgeon.   
 
Refer to SCHEMA in Appendix B. 
 
6.  STATISTICAL PLAN AND CONSIDERATIONS 
For assistance with plans for biostatistics in this research, please visit the Department of 
Health Studies at www.health.bsd.uchicago.edu. 
 
Discuss the following in detail: 
a) Sample size determination— Our sample size of twenty (20) patients is justified 
in that we believe recruitment can be accomplished within 9 months.  True pace 
of recruitment/refusal/crossover will drive the timeline of a future full-scale study, 
and may influence inclusion/exclusion criteria of the full-scale study.   
b) Power analysis or considerations—  Results of the study (i.e. the calculated 
ADC threshold) will be used to drive a power analysis for  a future larger study to 
determine if addition of DW-MRI to the care paradigm results in clinically 
meaningful improvement in care.   
c)  Statistical methods: DW-MRI differentiation metrics and abscess 
characterization  
• Qualitative analysis: The collection will be presented to two separate 
radiologists who will be blinded to patients’ history, laboratory results, 
findings from other imaging modalities, and final diagnosis. They will 
independently review the MR images for detection of collections (T2-
weighted images together with diffusion-weighted images and ADC maps 
(T2 + DW-MRI). ADC maps will be generated for each patient using a 
home grown software. Each radiologist will assign a score from a five-
point scale (1 = no abscess; 2 = probably not an abscess; 3 = equivocal; 4 
= possible abscess; 5 = definite abscess) based on the level of confidence 
in the diagnosis for each review session. A score of 4 or 5 will be 
considered as positive for diagnosis of abscess for each case. 
• Quantitative analysis: Following qualitative analysis, the same two 
radiologists independently will measure ADC of the collections in each 
patient on ADC maps. Mean and 10th percentile ADC values will be 
computed by placement of region of interest (ROI) on ADC maps using 
DW images as guide. Each ROI will be placed in the center of the 

Page 12 of 19                                                       Confidential                              IRB Approval Date: 
Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
collection over the darkest pixels on ADC maps keeping size as large 
as possible and avoiding the volume averaging from the surrounding 
tissue. The reference standard for the diagnosis of abscess will be 
based on the analysis of aspiration fluid from the collection. Statistical 
analysis: For statistical analyses, a software package (SPSS 11.0 for 
Windows; SPSS Inc., Chicago, IL, USA) will be used. Sensitivity and 
specificity of each review session for each radiologist will be calculated. 
McNemar’s test will be used for multiple comparisons of sensitivity of 
different review sessions. Confidence score of each review session will be 
compared using Wilcoxon-signed rank test. Two-tailed Student’s t test will 
be used for comparison of ADC values. A two-tailed p value of less than 
0.01 will be considered to indicate a statistically significant difference. 
Simple κ coefficients will be used to assess interobserver agreement for 
confidence score and ADC measurements. An ROC curve will be 
constructed for ADC values, and area under the curve measured the 
overall ability of ADC in differentiation of abscess from non-infected 
collections.  
d)  Subject Population(s) for Analysis 
• All-imaged population:  Any subject who underwent DW-MRI in the post-
operative setting after identification CT-proven intrabdominal collection > 
3 cm in average diameter, whom the surgeon determines based on best 
clinical practice that percutaneous drainage is indicated.     
e)  If any Intent to Treat Analysis will be done on subjects withdrawing before 
completion or those who remained in the study but withdrew from 
intervention, please describe in detail:  Not applicable  
 
7.  RISKS AND BENEFITS 
Describe in detail: 
NOTE:  Collection of data is through a noninvasive procedure (MRI) routinely 
employed in clinical practice.   Usual risk of MRI as described to patients undergoing 
this imaging is described below.   
a) Risks associated with study intervention and likelihood of these risks:  
Participation in this study may involve the following risks: 
a. Exposure to magnetic fields:  Apart from its effects on metal objects and 
implants, there are no known negative effects associated with the 
magnetic fields used to produce MRI images.  Despite the exposure of 
millions of people to high-intensity magnetic fields in MRI scanners 
over the last 30 years, there are no confirmed reports of adverse health 
effects. The radio-frequency energy that is used to excite the MRI 
signal may in extraordinary circumstances cause heating and burning of 
tissue. In addition, rapid switching of the gradients may cause transient 
discomfort.  In addition, there is a remote likelihood of tissue damage 
when rapidly changing magnetic fields are used. 
b. The presence of devices, implants, or other objects containing metal: 
Metal objects pose a serious risk to all patients undergoing MRI exams. 
This includes internally implanted objects such as surgical clips, 

Page 13 of 19                                                       Confidential                              IRB Approval Date: 
Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
biosupport devices (e.g., pacemakers), and artificial joints which contain 
metal. 
c. Claustrophobia:  Some individuals may experience claustrophobia 
during the MRI exam due to the limited space available inside the 
bore of the magnet. 
d. Incidental finding as a result of the study:  It is not anticipated that 
the DW-MRI will reveal an incidental finding that would not have 
been discovered during the cross sectional CT scan that was 
obtained during usual best clinical care.  Given the CT scan is not 
the study intervention, incidental finding is not an anticipated risk of 
the study.   
e. Inadvertent delay in percutaneous drainage:  Delay in percutaneous 
drainage could result in clinical worsening.   
b) Protection against risks 
 
a. Protection against risks related to exposure to magnetic fields: We will 
insure that our experimental pulse protocols do not exceed 75% of FDA 
recommended upper limits for power deposition and gradient slew rates.   
As a further protection, even if a higher energy pulse programming 
protocol were to be used in error, the commercial MRI machine that will 
be used for these studies (a Philips Achieva 1.5 Tesla scanner) is 
equipped with both software and hardware power limiters that prevent 
the execution of pulse sequences in excess of FDA limits.  The statistical 
evidence suggests that exposure to excessive RF energy caused by this 
equipment is, for all practical purposes, impossible -- there have been no 
reports of significant RF injury in over one hundred thousand clinical 
MRI exams. 
b. Protection against risks related to presence of metals, devices and other 
metal containing material: Participants are questioned carefully before 
MRI imaging to insure that they do not have metal implants. Prospective 
study participants who have such implants will be excluded from the 
study.  Patients who have worked in or near machine shops and 
electronics shops are also excluded from the study.  In these work 
environments metal slivers may become trapped in the eyes, posing a 
potential hazard if exposed to a strong magnetic field.  In addition, metal 
objects such as heavy key chains that are carried into the scan room can 
cause serious accidents.   Participants will be cautioned to remove all 
metal objects before entering the scan room.  Access to the scan room is 
carefully controlled to insure that no ferrous metal is inadvertently 
brought in. 
c. Protection against claustrophobia: Prospective participants will be 
counseled about this possibility before the exam.  The magnet is 
equipped with an intercom system enabling study subjects to 
communicate with the operators at any time during the exam. If they 
report any discomfort during the MRI examination they will be removed 
from the magnet immediately. 
d. Breach of confidentiality: There is a minimal risk that patient 
confidentiality may be breached. All data is entered in an online 
database. This database is password protected. Each patient is assigned a 
unique number, these unique numbers are matched with patient 
identifiers. 

Page 14 of 19                                                       Confidential                              IRB Approval Date: 
Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
e. Protection against inadvertent delay in percutaneous drainage: The 
study MRI is expected to be obtained during the natural lag-period 
that is typical after requesting a same-day drainage procedure.  In the 
event the interventional radiology team is immediately available to 
perform percutaneous drainage, the patient will become ineligible 
for the study and will not undergo MRI acquisition. The study 
authors emphasize the importance of not delaying percutaneous 
drainage as a therapeutic intervention and feel this plan adequately 
ameliorates any delay in percutaneous drainage, 
c) Potential direct benefits to subject:  There may be no benefit to patients who are 
enrolled in the study.  Direct benefit is low, as the DW-MRI will not be utilized in 
direct clinical decision-making in the study subjects (decision for or against 
percutaneous drainage will be based on current best practice which is clinical 
assessment combined with contrast-enhanced CT).   
d) If no direct benefit to the subject, describe potential benefit to community,  
disease population, or science: If hypothesis is correct and DW-MRI is superior 
to CT in characterizing abdominopelvic fluid collections, then results of the study 
may better guide selective percutaneous drainage of post-operative intra-
abdominal abscesses after colorectal resection, and prevent drainage of sterile 
collections.  Therefore risks are justified due to the importance of the knowledge 
that may reasonably be expected to result from the research.   
e) Describe how the benefits in this research justify the potential risks:  
Community benefit as stated above and lack of risk to the subject justify this 
study.  As stated above, there is no know risk of magnetic field exposure at this 
level, patients with stated claustrophobia will be excluded, and usual meticulous 
screening will be before to ensure participants do not have metal implants.   
 
8.  SAFETY AND ADVERSE EVENTS  
Discuss the following in detail. 
Safety: 
a) Overall risk benefit assessment:  Relative benefit and very low risk profile is 
justified.   
b) What provisions will be made to protect subject’s safety during the course of 
this study:  
a. Protection against risks related to exposure to magnetic fields: We 
will insure that our experimental pulse protocols do not exceed 75% 
of FDA recommended upper limits for power deposition and 
gradient slew rates.   As a further protection, even if a higher energy 
pulse programming protocol were to be used in error, the commercial 
MRI machine that will be used for these studies (a Philips Achieva 
1.5 Tesla scanner) is equipped with both software and hardware 
power limiters that prevent the execution of pulse sequences in 
excess of FDA limits.  The statistical evidence suggests that 
exposure to excessive RF energy caused by this equipment is, for all 
practical purposes, impossible -- there have been no reports of 
significant RF injury in over one hundred thousand clinical MRI 
exams. 

Page 15 of 19                                                       Confidential                              IRB Approval Date: 
Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
b. Protection against risks related to presence of metals, devices and 
other metal containing material: Participants are questioned 
carefully before MRI imaging to insure that they do not have metal 
implants. Prospective study participants who have such implants will 
be excluded from the study.  Patients who have worked in or near 
machine shops and electronics shops are also excluded from the 
study.  In these work environments metal slivers may become 
trapped in the eyes, posing a potential hazard if exposed to a strong 
magnetic field.  In addition, metal objects such as heavy key chains 
that are carried into the scan room can cause serious accidents.   
Participants will be cautioned to remove all metal objects before 
entering the scan room.  Access to the scan room is carefully 
controlled to insure that no ferrous metal is inadvertently brought in. 
c. Protection against claustrophobia: Prospective participants will be 
counseled about this possibility before the exam.  The magnet is 
equipped with an intercom system enabling study subjects to 
communicate with the operators at any time during the exam. If they 
report any discomfort during the MRI examination they will be 
removed from the magnet immediately. 
d. Protection against the breach of confidentiality: Patient identifier 
will be kept and used only for the purpose of correlating patient data 
between imaging studies and outcomes.  Patient identifier will be 
removed from data analysis unless it becomes necessary to correlate 
results of the analysis to other clinical data, which we do not expect.  
Patient identifier will be removed from all presentations and 
publications; only data from a group of patients will be reported so 
that data from any individual patient cannot be identified. 
e. Protection against inadvertent delay in percutaneous drainage: In 
the event the interventional radiology team is immediately available 
to perform percutaneous drainage, the patient will become ineligible 
for the study and will not undergo MRI acquisition. 
c) Adverse Events:  Not applicable—  collection of data is through a 
noninvasive procedure (MRI) routinely employed in clinical practice.    
 
9.  DATA HANDLING AND RECORD KEEPING  
Discuss the following in detail: 
a) How will data be collected?  Paper?  Electronically? The majority of data will 
be collected electronically via EHR and entered into an online database.  There is 
a chance minimal paper documents will be generated as well (example, consent 
form).   
b) Who will provide source documents and CRFs for data collection?  Dr. 
Hyman and Dr. Cannon will be performing consent, subject to revision if 
additional investigators or assistants join the study.   
c) Who will manage the data?  The data will be managed by the study investigators 
and when applicable a statistician who will be compliant with IRB policies and 
procedures.   
d) Where will data be stored? Any paper records or data sheets will be maintained 
in a locked cabinet; electronic data storage will be in an online database and 
comply will UCMC guidelines.   

Page 16 of 19                                                       Confidential                              IRB Approval Date: 
Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
e) Who will have access to data? Only the study investigators will have access to 
the data.  Research assistants who have undergone appropriate CITI training (i.e. 
a surgical resident) may also have access to the data.   
f) Describe provisions to protect subject’s confidentiality (must be in line with 
HIPAA requirements) 
a. labeling of data: Each DW-MRI will be assigned a unique number which 
will match with the identifier assigned to the patient.    
b. identifiers & PHI: Data will be de-identified.  Each patient is assigned a 
unique number, these unique numbers are matched with patient identifiers 
in a password protected database.  PHI collected may include admission 
date, procedure date, discharge date.  Patient age (year only), sex,  
 
 
10.  STUDY MONITORING, AUDITING AND INSPECTING  
All investigator-initiated studies must have a monitoring plan in place. 
a) The study investigators will serve as data monitors and assure compliance.   
 
11.  FINANCIAL CONSIDERATIONS 
a) Remuneration to subject - none 
b) Costs to subject - none 
 
12.  ETHICAL CONSIDERATIONS  
a) None identified.  
 
13.  CONFLICT OF INTEREST  
a) COI on file – no conflicts identified.   
 
14.  PUBLICATION PLAN  
Discuss the following in detail: 
a) Who expects to publish results from this research? – The PI and study 
investigators will publish the data in a surgical or radiologic journal.   
b) When are results expected to be submitted for publication? –  Preliminary 
findings from pilot study expected to be published in 2018.   
c) Who will be involved in the compilation of results for publication? – The PI 
and study investigators.  
 
15.  REFERENCES  
Kumar RR, et. al. Factors affecting the successful management of intra-abdominla 
abscesses with antibiotics and the need for percutaneous drainage.  Dis Colon Rectum. 
2005;49:183-189 
 
Siewart B, et. al. Impact of CT-guided drainage in the treatment of diverticular abscesses: 
size matters.  Am J Radiology. 2006;186:680-686 
 

Page 17 of 19                                                       Confidential                              IRB Approval Date: 
Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
Oto A, et. al. Diffusion-weighted MR imaging of abdominopelvic abscesses. Emerg 
Radiol 2011;18:515-524 
 
Sarkissian H, Hyman N, Osler T.  Postoperative fluid collection after colon resection: the 
utility of clinical assessment. Am J Surg 2013;206:551-554 
 
16.  APPENDIXES 
 
A. INFORMED CONSENT FORM 
See supporting attachments 
 
B. SCHEDULE OF EVENTS (SCHEMA) 
See supporting attachments 
 
C. DATA SAFETY AND MONITORING PLAN 
Discuss the following in detail: 
 
The study investigators will serve as data monitors and assure compliance.   
 
D. PATIENT DIARIES  
a) N/A 

Page 18 of 19                                                       Confidential                              IRB Approval Date: 
Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
 
E. FIGURES 
a) Figure 1 (Fig . 7 from Oto et. al.): 
 

Page 19 of 19                                                       Confidential                              IRB Approval Date: 
Pending 
Cannon, Hyman, Oto, Melvy                                                                        IRB approved Version#: Pending 
 
 
b) Figure 2: Project Design and Patient Flow 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Colorectal Resection 
Clinical suspicion of IAA 
CTAP + PO/IV 
No discrete 
collection 
Discrete > 3cm abdominopelvic  
collection identified 
DW-MRI 
Drainage 
Gram Stain 
Culture 
Qualitative fluid 
Surgeon determines percutaneous 
drainage is indicated