Mitchell C Raeside1, Andrea Agostini1, Richard K.G. Do1, Amita Shukla-Dave1,2, David Aramburu-Nunez2, Ramesh Paudyal2, Olga Smelianskaia1, Monika Khan1, David Kelsen3, and Lorenzo Mannelli1
1Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY, United States, 2Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY, United States, 3Medicine, Memorial Sloan-Kettering Cancer Center, New York, NY, United States
Synopsis
The
purpose of this study was to develop and optimize a rapid MR pancreas screening
protocol to be performed in conjunction with breast MRI screening in
BRCA-positive individuals. 15 patients underwent a rapid pancreatic screening
at the conclusion of their breast MRI examination. Images were acquired with the patient in the
prone position, with the breast coil still in place, but using the built-in
body coil on a 3T magnet, and evaluated for image quality (including SNR and
CNR), and detection of pancreatic lesions. Rapid MR protocol for pancreatic cancer
screening is feasible and provides diagnostic quality images.Purpose
BRCA1 and BRCA2
carriers are at increased risk of pancreatic cancer, with a 5% lifetime risk
and a relative risk of 1.5-9.01. Population-based screening for
pancreatic cancer has not been recommended2 due to the low incidence of
pancreatic cancer in the general population and because screening is either
invasive (e.g. endoscopic ultrasound (EUS)) and/or
expensive (e.g. magnetic resonance cholangiopancreatography (MRCP)). Although
pancreatic cancer screening is recommended for high-risk individuals2,3, no
established screening tool is available. BRCA positive patients do however
undergo MRI screening for breast cancer, which is recommended annually between
the ages of 25 and 753.
The purpose of this study was to develop and optimize a
rapid MR pancreas screening protocol to be performed in conjunction with breast
MRI screening in BRCA-positive individuals.
Methods
This prospective study was approved by the
local IRB. Inclusion criteria: BRCA1 or BRCA2 mutation, age 25 years or older,
female, and undergoing screening breast MRI.
The rapid screening protocol was designed
to be completed in less than 10 minutes at the completion of the breast MRI
examination. The images were acquired with the patient in the prone position,
with the breast coil still in place, but using the built-in body coil without
placement of a dedicated body surface coil. All studies were performed on a 3T
GE MR 750 magnet.
Sequences performed included T2 SSFSE axial
and coronal, T1 axial post-contrast, and reduced field of view (rFOV) DWI (b=0,
20, 50, 80, 250, 500 and 800 s/mm2); sequence details are reported
in Table 1. Variable NEX were used for rDWI. Image quality was qualitatively
assessed by two radiologists in consensus with a grading score system of 1-5,
with 1 = all diagnostic information present, and 5 = non-diagnostic. Following subject 1, parameters for axial
T1-post-contrast and rFOV DWI were modified to improve image quality (Table
1). The imaging protocol was modified
until diagnostic images (score of 1) were achieved for 5 consecutive patients,
at which point the protocol was considered optimized. Images were reviewed by
the same two radiologists in consensus for detection of pancreatic lesions.
Signal-to-noise-ratio (SNR),
contrast-to-noise-ratio (CNR) and ADC were assessed with manually placed
regions-of-interest (ROI) in the pancreatic head, body, and tail. As not all
sequences included background air, estimates were made using direct measurement
of the pancreas:
$$SNR_{pancreas} = \frac
{S_{pancreas}}{SD_{pancreas}}$$
$$CNR_{pancreas} = \frac
{S_{pancreas}-S_{peri-pancreatic fat}}{SD_{peri-pancreatic fat}}$$
Results
Between
July and October 2015, 15 BRCA-positive individuals undergoing routine
screening breast MRI underwent a rapid pancreatic screening protocol at the
conclusion of their breast MRI examination. The rapid pancreas protocol was
successfully completed in all patients. Average time per sequence, SNR, and CNR
measurements are reported in Tables 2 and 3. Image quality was rated as 1 (all
diagnostic information present) for all patients for the axial and coronal T2
SSFSE and T1 post-contrast sequences. Excellent image quality was achieved for
low b-values; however, image quality at higher b-values was more variable.
Calculated ADC values for the pancreatic head, body and tail were 1.42, 1.51,
and 1.54x10-3 mm2/s respectively. In 3 of 15 subjects,
small pancreatic cystic lesions were detected. In 1 subject an hepatic adenoma
was identified.
Discussion
This study demonstrates that rapid pancreas
screening using the built-in body coil on a 3T magnet is both feasible and
yields diagnostic image quality able to detect abnormalities within the
pancreas. Combined with breast MRI screening, this is a rapid, safe,
non-invasive, and potentially inexpensive screening tool. With minimal
inconvenience to the patient, this screening protocol can be utilized in the
BRCA population where currently there is no established screening tool
available.
Image quality was still diagnostic even in
a subject with a Body mass index of 34.1 kg/m2 (Figure 1). The rate
of observed positive subjects (3 of 15 subjects) in this small group of BRCA1
and BRCA2 mutation carriers is within the range of expected pancreatic lesions
in this population4. 2 of 3 subjects positive for cystic lesions underwent
dedicated MRCP which did not detect additional pancreatic lesions.
This study was not designed to assess the
effectiveness or indications of pancreatic cancer screening itself, but rather
to develop a new screening tool which could be further evaluated in larger clinical trials.
Conclusion
Rapid
MR protocol for pancreatic cancer screening with subjects in the prone position
and use of the built-in-body coil is feasible and provides diagnostic quality
images. Ultimately 30 subjects will be enrolled into this pilot study, and in
the final version of the protocol we plan to use 3 b-values, probably 0, 20,
and 500 s/mm
2.
Acknowledgements
No acknowledgement found.References
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2. Canto M, Harinck F, Hruban R, et al.
International cancer of the pancreas screening (CAPS) consortium summit on the
management of patients with increased risk for familial pancreatic cancer. Gut.
2013; 62(3):339-47
3. NCCN Clinical Practice Guidelines in Oncology.
Breast cancer screening and diagnosis. Version 1.2015. NCCN.org
4.
Canto M, Hruban R, Fishman E, et al. Frequent
detection of pancreatic lesions in asymptomatic high-risk individuals.
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