Evaluation of Pancreatic Lesions by Computed Tomography Scan: A Study Protocol

Background: The pancreas is a hidden organ and was one of the last organs in the abdomen to be analyzed by anatomists, physiologists, physicians, and surgeons. Pancreatic lesions may range from mild inflammation to malignancy. Ultrasound was the first cross-sectional technique that permitted direct imaging of the pancreas. It permitted precise visualization of pancreatic parenchyma, pancreatic ducts and bile ducts. This study aims to evaluate various pancreatic lesions using CT scan and assess their correlation with histopathological findings. Methodology: This will be an observational study conducted at department of radiodiagnosis, AVBRH, Wardha. Total 180 patients with pancreatic disease confirmed by clinical, laboratory and ultrasonography will be enrolled in the study. All 180 patients will undergo plain and contrast enhanced CT scan. Results will be judged, based on the observations and finding on CT scan, biochemical and histopathological reports whenever possible. Modified CT Severity Index / Mortele Modified CTSI Scoring will be used to assess severity of acute pancreatitis and acute exacerbation of chronic pancreatitis. Results: We expect to explore on the common etiological factors, gender and age distribution of various pancreatic diseases. Correlation between grade of acute pancreatitis according to modified CT severity index and clinical outcome of patients. In case of chronic will be evaluated. Study Protocol Gulve et al.; JPRI, 33(64A): 44-50, 2021; Article no.JPRI.81037 45 Conclusion: CECT is excellent diagnostic modality to stage severity of inflammatory process and staging of neoplastic lesions. Severity grading in acute exacerbation of chronic pancreatitis will be meticulously observed and significant conclusive findings will be found. CECT imaging with its postprocessing techniques represents the image of choice for diagnosis and predicting pancreatic masses.


INTRODUCTION
The pancreas is a hidden organ and was one of the last organs in the abdomen to be analyzed by anatomists, physiologists, physicians, and surgeons [1]. The pancreas has its first mention in literature around 200 B.C., when it was referred to as the 'finger of the liver' in the Talmud. The pancreas was given its name by Rufus of Ephesus, a Greek anatomist. The term 'pancreas' is derived from a Greek word which means 'whole flesh' possibly because of its fleshy consistency [2]. Galen proposed that it had the role in supporting and protecting blood vessels. The pancreas was considered as a cushion for the stomach by Vesalius. It was Wirsung who first demonstrated the ducts in human's pancreas in 1642 [1]. The histological structure of the pancreas was first described in 1869 by Langerhans and subsequently by Heidenhain [3].
In 1967, Josef Rosch published an article in American Journal of Roentgenology in which he mentioned that the pancreas was a difficult organ to image Roentgenologically since it is small and situated deep in the retroperitoneal space. The Roentgenologic diagnosis of pancreatic disease relies on the change induced by the pathologic process in the surrounding organs [4,5].
Ultrasound was the first cross-sectional technique that permitted direct imaging of the pancreas. It permitted precise visualization of pancreatic parenchyma, pancreatic ducts and bile ducts [4,6]. Bowel gas remains the single most important obstacle for obtaining excellent ultrasound studies [6]. Even with a meticulous scanning technique, the pancreas cannot be visualized in 10% of the patients. CT scan is then extremely beneficial in such patients [4,5].
CT of the pancreas began in the late 1970's with simultaneous publication by authors like Kreel, Stephens et al and Haaga et al in 1976 [5]. Computed tomography is the non-invasive modality. It makes the use of computed processed combination of many x-ray measurements taken from different angles. It is also known as COMPUTED AXIAL TOMOGRAPHY [5,7]. Initially only pancreatic masses or contour abnormalities could be detected. Helical CT scanners introduced in late 1980 allowed much faster accession of data with a slice thickness of 1-2mm and three dimensional imaging [7]. Subsequently improvements in scanner technology and use of bolus injection of intra-venous contrast material enabled imaging of normal pancreatic parenchyma, Pancreatic duct and peripancreatic vascular structures [4,5,7]. CT has become the method of choice for evaluating the pancreas, detecting pancreatic lesions, assessing its severity, and determining its etiology [5,7,8].
Imaging in pancreatic lesion is challenging as pancreas are located retroperitoneally and with close proximity to bowel and major blood vessels [9,10]. Pancreatic lesions include the spectrum of disease ranging from inflammation and its complication to malignancy [11,12]. Pancreatic lesions are associated with high morbidity and comorbidity [11]. Multi-detector computed tomography scan is modality of choice for detecting pancreatic pathology. It is highly sensitive in detecting necrosis, pancreatitis, peripancreatic fluid collections, calcification, neoplasm, pancreatic enlargement, atrophy and cystic lesions of pancreas. CT has been shown to be the best imaging modality, being more sensitive than ultrasound for detection of pancreatic injury [5,7]. CT scan has made it possible to identify and detect various benign and malignant pancreatic lesions. In neoplastic conditions, CT scan can give an idea about extent of disease, tissue component, accurately depict tumor morphology, ductal anatomy and its relationship with the surrounding organs. CT scan is also widely used in the preoperative staging of P#pancreatic neoplasm and also allows accurate post treatment follow up [4,5,7].
CT scan is popular for diagnosing the pancreatic pathology due its availability and easy interpretation of CT images by Radiologist. CT has the benefit of high accuracy over ultrasound in pancreatic lesions [13]. Ultrasound has limitation in evaluating pancreas as most of times it is obscured by bowel gases [6,13]. CT scan can easily detect the pancreatic and extra pancreatic spread of disease. CT scan has benefit of comparative low cost, less time consumption, and detection of concretions over magnetic resonance imaging [5,7].
Radiological evaluation with CT scan is has become very essential for diagnosing the pancreatic lesions and planning their proper treatment. So CT become the method of choice in evaluating the pancreas, in detecting a pancreatic lesion, assessing its extent, defining its etiology and planning proper treatment [4,5,7].
As CT scan is highly reliable, can be easily performed. It has advantage of accuracy and accessibility [5]. So present study is done to evaluate role of computed tomography in various pancreatic lesions include the spectrum of disease ranging from inflammation and its complication to malignancy, their characteristic appearance, clinical, biochemical and histopathological correlations [9][10][11][12]. In almost all the studies acute exacerbation of chronic pancreatitis is not separately mentioned and is included in chronic pancreatitis. In present study we have tried to describe the cases of acute exacerbation of chronic pancreatitis separately.

Rationale
CT scan is highly reliable, can be easily performed. It has advantage of accuracy and accessibility. CT scan has primary role in evaluation of pancreatitis trauma and malignancy. It detects with not only parenchymal abnormalities but also extra pancreatic spread of disease. In pancreatic neoplasm MDCT accurately depict tumor morphology, ductal anatomy and its relationship with surrounding organs.

MATERIAL AND METHODOLOGY
This is observational study which included the patients from (July 2018 to June 2020) came to department of radiodiagnosis, Jawaharlal Nehru Medical College and Acharya Vinoba Bhave Rural Hospital, Sawangi, Wardha.

Study Design
Prospective observational study.

Study Place
Patients came to department of radio-diagnosis, Jawaharlal Nehru Medical College and Acharya Vinoba Bhave Rural Hospital, Sawangi, Wardha. Both inpatient department (IPD) and outpatient's department (OPD)patients were included.

Duration of Study
Study will be conducted during period from July 2018 to June 2020.

Study Population
The study conducted on patients of either sex referred to department of radiodiagnosis, Jawaharlal Nehru Medical College and Acharya Vinoba Bhave Rural Hospital, Sawangi, Wardha after taking a written informed consent that fulfilled the inclusion criteria.

Sample Size
A total of 180 patients who presented with symptoms related to pancreatic disease referred to department of radiodiagnosis, Jawaharlal Nehru Medical College and Acharya Vinoba Bhave Rural Hospital (AVBRH) , Sawangi, Wardha were taken for study.

Inclusion criteria
1) Patients presented with complaints related to pancreas and clinically diagnosed. 2) Patients undergone ultrasonography with high suspicious of pancreatic pathology.

3) Patients with deranged biochemical tests
for pancreas.
2) Pregnant females presenting with complaints of pancreatic lesion 3) Patients allergic to contrast media 4) Patients not willing to participate.

Methodology of Study
 The pre-tested, semi structured questionnaire developed and used for data collection. Patient were informed and explained about the study. Written informed consent had been taken prior to procedures as per attached proforma.  Clinical and consequential data were documented by a predesigned proforma.  Patient will be kept nil per os for 6 to 8 hours.  Serum creatinine will be done  Patient will be placed on gantry table in supine position with both hands above the head.  A scanogram will be taken in inspiration / expiration  Initially a non-contrast CT scan will be taken. (only oral contrast is given most commonly used here will be positive contrast Urograffin)  Then the oral and intravenous contrast will be given to the patient and then contrast enhanced CT scan will be taken( commonly used intravenous contrast in AVBRH will be positive contrast Omnipaque or Ultravist (300mg iodine) both 2ml per kg of body weight and given at the rate of 2.8ml/sec at 280 psi)  Pancreatic parenchymal phase will be taken at delay of 50 second after contrast injection, portal venous phase at 70 second delay and delayed phase at 6-10 mins.  Then the lateral decubitus view with patient lying on his right side will be taken.  Acquisition of axial section will be done in cranio-caudal direction from the level of xiphisternum to pubis symphysis  Axial sections will be taken of slice thickness of 5mm and then reconstructed to thickness of 1.5mm  Results will be judged, based on the observations and finding on CT scan, biochemical and histopathological reports whenever possible.  Modified CT Severity Index / Mortele Modified CTSI Scoring will be used to assess severity of acute pancreatitis and acute exacerbation of chronic pancreatitis.  The observations will be graphically depicted and with the help of tables and graphs and conclusions is drawn on the basis of observations and discussion.  The data obtained will be compiled in tabular form and analyzed and suitable statistical tests applied for results.

Tools for Assessment Of Severity
"Modified CTSI [13] Scores are generated by estimating pancreatic inflammation and necrosis to give a score out of 10.

EXPECTED RESULTS
In this study we expect to find out the common etiological factor age group and symptoms of pancreatic pathologies. We also intend to find common computed tomographic findings of various pancreatic pathologies. We expect positive correlation between modified CTSI and clinical outcome of patients. We expect high sensitivity of CECT in diagnosis of benign and malignant pancreatic neoplasm. In case of pancreatic trauma we intend to grade them according to AAST scale and correlate it with clinical outcome

DISCUSSION
Pancreatic disease are associated with high mortality. Computed tomography is imaging modality of choice for diagnosing pancreatic pathology .It has high accuracy in detecting pancreatic lesions and their nature. It also helps in grading of acute pancreatitis and revealing its prognosis by modified computed tomography severity index. Problems of pancreatic disease are evident from GBD Studies [14][15][16]. Studies on related aspects of pancreatic disease were reported by Gawande-Kirnake [17] and Kambale et. al. [18]. Studies on use of computed tomography were reported [19][20][21]. In many studies there is positive corelation between modified CTSI and clinical outcome in terms of infection, hospital stay and need for intervention. In cases of chronic pancreatitis duct dilatation, pancreatic calcifications and parenchymal atrophy are visible on CT scan thus helping in easy and rapid diagnosis. Serum amylase and serum lipase are increased in the cases of acute pancreatitis but in chronic pancreatitis there can be serum amylase and lipase insufficiency. We will be discussing acute exacerbation of chronic pancreatitis as separate entity with imaging changes. We will be applying modified CTSI to acute exacerbation of chronic pancreatitis and will be observing clinical outcome of it. It also helps in staging of pancreatic neoplasm and preoperative planning for resection. Various biochemical tumor markers are increased in cases of pancreatic neoplasm [22][23][24][25][26][27][28][29][30].

CONCLUSION
CECT is excellent diagnostic modality to stage severity of inflammatory process and staging of neoplastic lesions. Severity grading in acute exacerbation of chronic pancreatitis will be meticulously observed and significant conclusive findings will be found. CECT imaging with its postprocessing techniques represents the image of choice for diagnosis and predicting pancreatic masses. It is a standard investigation to identify and quantify distribution of various pancreatic lesions and also evaluates activeness and progression of disease. It helps in accurate diagnosis and characterization of lesion and in proper treatment of patients.

CONSENT
After taking patient's written informed consent that fulfilled the inclusion criteria.

ETHICAL APPROVAL
As per international standard or university standard written ethical approval will be collected and preserved by the author(s).