CT and MRI Abdominal Imaging Studies: A Student Case Series

Instructor: Terry Duggan-Jahns, RT(R)(CT)(MR)(M)

Contributing Students: Gina Abueg, RT(R)(M), Patty Johnson, Andrea Keely, Chuck Manning, RT(R), Judy Race, RT(R), Wilma Steiner, Duane Troxler, RT(R), and Marissa Withrow, RT(R)

Disclosures: The authors report having no significant financial or advisory relationships with corporate organizations related to this activity.

ABSTRACT

Imaging studies with computed tomography (CT), magnetic resonance imaging (MRI), and other advanced modalities have revolutionized the delivery of effective medical care in a variety of abdominal clinical presentations, including suspected thrombosis, hemorrhage, or malignancies, as well as traumatic injuries and chronic back pain. Therefore, radiologic technologists and students training to become radiologic technologist professionals need a wide range of knowledge in CT and MRI methods for assessing illnesses and pathology in their patients. This article was developed under the supervision of Terry Duggan-Jahns, RT(R)(CT)(MR)(M), with the participation of radiologic technology students and radiologic technologists, offering them the ability to present interesting cases involving CT and MRI studies of the abdomen and pelvis. Meanwhile, readers will be provided with an educational opportunity to review the proper patient preparations, examination procedures, and findings in real-world cases of kidney disease, liver disease, abdominal abscesses, lymphoma, traumatic injury, and abdominal aortic aneurysm.

Introduction
Radiologic technologists require a wide breadth of knowledge to fully apply current imaging techniques to a variety of patient presentations. Computed tomography (CT) and magnetic resonance imaging (MRI) are 2 valuable modalities in imaging studies of the abdomen and pelvis, and radiologic technologists should be familiar with proper patient preparation, examination setup, examination parameters, and possible findings in clinical applications of CT and MRI. Through a series of case studies, this article will address techniques used to perform imaging studies in patients presenting with problems as varied as chronic kidney disease, kidney disease of unknown etiology, abdominal abscess, lymphoma, abdominal aortic aneurysm, liver hemangioma, and traumatic pelvic injury.

Imaging Kidney Disease
The kidneys are a pair of bean-shaped organs located in the back of the abdomen, situated on either side of the spine and behind the peritoneum. The basic functional unit of the kidney is the nephron, which is a long, tubular structure with distinct segments that exhibit different structure and transport functions. Main physiologic roles of the kidneys include the removal of nitrogenous waste, mainly in the form of urea, the maintenance of electrolytes (salt and other minerals), the maintenance of water balance, and the regulation of acid-base balance. The kidneys are also responsible for releasing various hormones into the bloodstream. Urine is produced in the kidneys to release waste products. When the kidneys become damaged due to injury or pathologic reasons, waste products can build up in the body, causing changes in urination or urinary output, pain, swelling, fever, weight loss, or general malaise.¹

Acute kidney failure describes the loss of kidney function over several hours or days. While severe systemic infections can result in acute kidney failure, the use of antibiotics has reduced the risk of acute kidney failure from this cause. Most cases of acute kidney failure are now due to drug toxicity, and it typically develops between 5 days and 5 weeks after drug exposure. Although some irreversible cases have been reported, most cases of acute kidney failure related to drug exposure can be resolved with the discontinuation of the responsible drug.²

Meanwhile, chronic kidney failure occurs due to long-term changes in kidney function, usually stemming from toxin exposure, metabolic diseases, or inherited disorders.² Diabetes and high blood pressure are the most common causes of chronic kidney disease (CKD), and the risk of developing chronic kidney disease increases with age.³

The following cases discuss 2 instances in which patients were imaged with suspected kidney disease.

Case 1: Chronic Kidney Disease
Gina Abueg, RT(R)(M) and Andrea Keely

Background
The patient is a 69-year-old male with a complicated medical history. History includes but is not limited to CKD, chronic liver disease, cholangitis, ulcerative colitis, and lymphoma. His most recent abdominal and pelvic CT was ordered to assess recurring lymphomas in the spleen, adrenal glands, and pelvis. The patient was complaining of weight loss, fatigue, and sweats.

Patient Preparation and Examination Setup
The patient is prepared for abdominal and pelvic CT studies with contrast. The approach to patients about to undergo a contrast-enhanced examination has 3 general goals: (1) to assure that the administration of contrast is appropriate for the patient and the indication; (2) to minimize the likelihood of a contrast reaction; and (3) to be fully prepared to treat a reaction should one occur. In this case, the following is done:

• Blood work for blood urea nitrogen and creatinine level
• Fasting 4 to 6 hours prior to the examination
• 450-mL barium sulfate suspensions 1.5 hours prior to the examination
• Consent form is signed.
• 22-g intravenous (IV) in left antecubital vein
• 125 mL iodinated IV CT contrast (ioversol)
• Patient is positioned supine, feet first.
• IV connected to auto-injector

Examination Parameters
A scout of the abdomen and pelvis was performed. Iodinated IV CT contrast (ioversol) was administered at a rate of 2.5 mL per second. Approximately 60 seconds after the injection, axial scans with 3-mm thickness and 400 field of view were performed, starting just above the liver and down to the ischium (Figure 1). The technique was set to 125 kilovolt peak and 250 milliampere seconds.

Findings and Discussion
The lower lung fields are unremarkable. There is air in the biliary tree. The patient's status is post-cholecystectomy. Spleen is unremarkable. Adrenal glands and pancreas are normal. Atrophic native kidneys are again identified with renal transplant in the left lower quadrant. Partial hemicolectomy and ostomy also are seen. An adenopathy or mass suggestive of recurrent lymphoma is not noted.

Case Summary
Twenty-six million Americans have been diagnosed with CKD and millions more are at great risk.³ CKD is the loss of kidney function, which happens gradually and is usually permanent.⁴ Other conditions that can affect kidney function include glomerulonephritis, inherited diseases such as polycystic kidney disease, fetal malformations, lupus, and other diseases that affect the body's immune system, obstructions caused by problems such as kidney stones, tumors or an enlarged prostate gland, and repeated urinary infections. Most cases of CKD are caused by diabetes and high blood pressure.³ People with CKD may develop anemia, high blood pressure, acidosis, cholesterol, and fatty acid disorders, and bone disease.⁴ The majority of patients with CKD die of heart disease.³ It is critical to conduct laboratory tests that reflect kidney function, including creatinine and blood urea nitrogen, in patients with suspected kidney disease who plan to undergo CT with contrast because the contrast agent can affect kidney function and cause an adverse reaction. Also, patients should be instructed to fast 4 to 6 hours prior to the examination to ensure proper uptake of the CT oral contrast agent.⁵

Previous surgery, which has either disrupted the sphincter of Oddi or created a new enteric biliary communication, is the most common cause of biliary tree air. Examples of these surgeries include endoscopic or surgical sphincterotomies, choledochoenterostomies, or cholecysto-enterostomies.⁶

Diaphoresis, weight loss, fatigue, and fever are symptoms of lymphoma.⁷ Because the patient did not have a fever, lymphoma was probably not the cause of symptoms.

Case 2: CT Kidney Protocols (Abdomen, Pelvis, and Kidney)
Chuck Manning, RT(R)

Background
A 75-year-old male presents with a known mass of the right kidney. Originally, the patient presented with right flank pain. Prior CT of the abdomen and pelvis are unavailable.⁸

Patient Preparation and Examination Setup

• Oral contrast: None
• Iodinated IV contrast: 100-mL (iopamidol) per protocol
• Patient is positioned supine, feet first.
• Centering at xiphoid
• Scout images: anteroposterior (AP) and lateral
• Creatinine levels were checked.

Examination Parameters
Scout images AP and lateral
Volumetric acquisition CTs were performed with reconstructions for display purposes (Figure 2). Helical noncontrast-enhanced CT was used to evaluate the kidneys with adjacent 5-mm slices through the region of the kidneys. This was followed by a parenchymal phase of the kidneys at 5-mm slice thickness and 5-mm interval, and then by a calyceal phase of the kidneys.

Two scout images were obtained—an AP and a lateral image. Noncontrast 5-mm scan through the kidneys was performed, followed by an IV-enhanced 5-mm scan through the kidneys for arterial evaluation, including a 3 to 5 minute delay scan (Figure 3).

This examination should include precontrast and postcontrast phases, including arteriographic phase. Multiplanar reconstructions and 3-dimensional (3D) volume-rendered images are helpful for surgical planning. Preoperative staging is important to the surgeon in planning the procedure.⁹

Findings and Discussions
Findings include a coarse calcification within the right renal mass. Multilobular mass presents in the right kidney, beginning at the superior pole where there is component that extends medially into the renal pelvis. The mass measures 7.2 cm x 10 x 6.5 cm in axial images. The mass has a heterogenous appearance with calcifications and some areas of necrosis. The calyceal phase scan of the kidney shows the mass to stretch and obliterating portions of the right renal collecting structures. The distal right ureter appears unremarkable. There is no evidence of metastatic disease, such as renal cell carcinoma.

Case Summary
The patient is evaluated for angiomyolipoma (AML), which is a benign renal neoplasm composed of fat and vascular components. Imaging of renal masses with CT often involves a noncontrast kidney scan followed by a kidney scan with contrast to provide full diagnostic information.¹⁰ AML occurs sporadically and accounts for 80% of tumors. Most small AML lesions are small and single, although they vary in size from a few millimeters to larger than 20 cm. Treatment includes partial nephrectomy. There is no universal follow-up for these treatments. Renal cell carcinoma is the most common form of kidney cancer arising from renal tubule.¹¹ The 5-year survival rate depends on the stage and whether surgery is performed. It ranges from less than 20% in unresectable tumors to 95% when resection is performed for T1 tumors.¹² Surgery is usually the preferred treatment for tumors that have not metastasized.¹³

Imaging Suspected Abdominal Abscess
Abdominal pain is a common symptom and can be related to disorders associated with any of the internal organs, including the liver, spleen, intestine, bladder, uterus, ovaries, or pancreas. Disorders related to glands, lymph nodes, arteries, veins, nerves, or musculature can also result in abdominal pain. Abdominal abscess, which presents with abdominal pain and fever, can be easily misdiagnosed because the symptoms are often nonspecific and associated with a variety of less serious problems. Radiologic studies are therefore needed to differentiate abdominal abscess from other problems, such as abdominal tumors and cysts, and to determine the size and position of an abscess. In almost all cases of abdominal abscess, the resulting pus must be drained by either surgery or needle aspiration, which requires guidance with CT or ultrasound imaging.¹⁴

Lymphoma is a cancer that begins in the lymph system, and affected lymph nodes can be located in the abdomen. Abdominal masses that are thought to be lymphoma are biopsied to confirm diagnosis and determine the most appropriate treatment course.¹⁵

The following cases illustrate the use of CT in the diagnosis and management of abdominal abscess and lymphoma.

Case 3: CT Imaging of an Abdominal Abscess
Marissa Withrow, RT(R)

Background
The patient is a 9-year-old female who underwent an appendectomy on September 28 for a perforated appendix with peritonitis and discharged home on October 5. A follow-up in the office October 13 noted increased abdomen pain, fever, vomiting, constipation, and with a blood test workup found an increased white blood cell count. It was discovered the patient did not receive the continued course of antibiotics. Based on these findings an abdominal and pelvic CT with IV contrast was ordered by the inpatient doctor.

Patient Preparation and Examination Setup
The patient was noted as "nothing by mouth" immediately and screened prior to the scan to determine whether oral and/or IV contrast could be given; there were no contraindications. The patient was given oral contrast mixture of 20 mL iohexol 300 in 480 mL of liquid to drink approximately 1 hour before receiving the scan to line the gastrointestinal tract. There was also an IV placed for IV contrast, which was given once in CT. Once the preparation was completed, the patient was placed supine on the table and given 60 mL iohexol 350 for IV contrast to better visualize soft tissue structures within the abdomen and to highlight any infection.

Examination Parameters
A CT scan of the abdomen and pelvis with IV and oral contrast is performed using a 128-slice scanner (Figure 4). The window level is 2 with axial 2-mm slices with 213 slices taken. One hundred and twenty-eight sagittal and 97 coronal reformats were done after the scan was completed.

Findings and Discussions
Findings include the following:

1. Large walled-off low attenuation collection containing a small amount of gas within the pelvis. This measures 4.9 x 6.3 x 4.7 cm and is consistent with an abscess. A discussion with the interventional radiology doctor finds that this can be percutaneously drained by a gluteal approach.
2. Dilated small bowel likely related to ileus due to inflammation of the bowel within the pelvis. The sigmoid colon and rectum are compressed by the inflammatory changes and abscess within the pelvis and no contrast material is seen beyond the upper pelvis anteriorly.
3. There is some mild retroperitoneal lymphadenopathy bilaterally tracking along the aorta.

Case Summary
Intravenous antibiotics are given to treat the infection and in this case a drain is placed. Appendicitis is most common in children and young adults, and approximately 1 in 15 people will get appendicitis.¹⁶ A ruptured appendix occurs 30% to 45% of the time.¹⁷ Dilated small bowel, or ileus (bowel obstruction), can occur due to inflammation of the peritoneum, and is most commonly related to recent abdominal surgeries or other inflammations such as appendicitis or pancreatitis.¹⁸ Approximately 20% of people with a ruptured appendix develop an abdominal abscess.¹⁹ If the abscess is large, drainage may be necessary and a drain may be placed until the infection is clear.^16,20

Case 4: Lymphoma
Judy Race, RT(R)

Background
The patient is a 27-year-old female who is complaining of abdominal pain. No palpable inconsistencies were found upon physical examination. An abdominal ultrasound was ordered. The ultrasound found 3 simple cysts within the spleen, and otherwise it was an unremarkable study. A CT scan with contrast was ordered for the next day.

Patient Preparation and Examination Setup
A 16-slice CT scanner was used for this study. The patient was screened for pregnancy and told not to eat anything after midnight the night prior to the examination. She was given 16 oz of oral contrast to take first thing in the morning. She took another 16 oz of oral contrast 30 minutes prior to her examination. The patient drank another 8 oz of barium upon arrival to her examination. The first abdominal scan was without contrast. IV contrast of 100 mL of iodinated CT contrast (iohexol 300) was given after the first scan without contrast. During the scans, the patient was instructed to take in a deep breath and hold it, and once the scan was done the patient was told to breathe normally.

Examination Parameters
Using a 16-slice CT scanner, 3 series were run: topogram, first helical/spiral scan of the abdomen/pelvis with a 65-second delay, and second helical/spiral scan with IV contrast with a 5-minute delayed imaging. The scans were run with 100 mL of iohexol IV contrast. There were 4 postprocessing images from the 2 helical images (Figure 5). The Table 1 outlines the examination scanning parameters for each scan in this case (scanning parameters can vary considerably depending on the facility, operator and radiologist preferences, and other factors).

Findings and Discussions
Contiguous axial images were obtained through the abdomen and pelvis following the oral administration of contrast material and IV administration of 100 mL iodinated CT contrast (iohexol 300).

There is an 8-cm, large, ill-defined mass, which appears to arise at the root of the mesentery and extends to the right anterior abdomen. The soft tissue component of this mass measures 12 x 6.2 x 8.2 cm, and there is infiltration of the fat surrounding the pancreas and regional vasculature (celiac axis, splenoportal confluence, and superior mesenteric artery). There are multiple mildly enlarged mesenteric lymph nodes separate from the aforementioned mass; a representative node measures 1.6 x 1 cm, series 2, image 39.

There is a large retroperitoneal/mesenteric mass, which is concerning for neoplasm, most likely lymphoma. Differential considerations include retroperitoneal sarcoma. The mass is amenable to percutaneous biopsy under CT guidance which could be performed at the patient's earliest convenience.

There are multiple hypodense splenic lesions, which may reflect lymphomatous involvement. The spleen itself is not enlarged.

Case Summary
Lymphoma describes a cancer that arises from the lymph system, which is a network of tubes that carry fluid from tissues back to the bloodstream. There are several different types of lymphoma related to the specific types of lymphocytes (lymph cells) that are affected by the cancer. In fact, there are at least 10 different types of non-Hodgkin lymphoma alone. It is important to identify the type and subtype of lymphoma when making a diagnosis because this information can determine which of the available treatments is most likely to be effective.¹⁵

The symptoms of lymphoma include¹⁵:

• Painless swollen lymph nodes in the neck, underarm, groin, chest, or abdomen
• Unexplained fever, weight loss, or night sweats—sometimes called "B symptoms"
• Ongoing fatigue
• Itchy skin
• Red bumps on the skin
• Swelling in the face, neck, or upper chest, caused by lymphoma pressing on the major vein that drains blood from these areas
• Feeling of fullness in the abdomen from an enlarged liver, spleen, or lymph nodes
• Abdominal problems, such as nausea, vomiting, and indigestion

There are several types of treatments for lymphoma depending on the type and the course of action of when it is found. This case is currently awaiting pathology results of a biopsy and a consult is being requested for evaluation for possible resection.

Imaging of the Abdominal Aorta
The abdominal aorta is the main artery that carries blood from the heart to the rest of the body.²¹ Almost every artery in the body branches from the aorta. An abdominal aortic aneurysm (AAA) is an enlargement that occurs in this artery. Most AAAs occur gradually in a process that can take several years. The enlargement associated with an AAA occurs due to a weakening in the aortic wall. While a specific cause of AAAs has not been identified, known risk factors include atherosclerosis, or hardening of the arteries; cigarette smoking; high blood pressure; genetics; and infection or trauma. The most pressing clinical concern in patients with a confirmed AAA is the possibility of aneurysm rupture, which results in excessive internal bleeding and therefore carries a high mortality rate. The mortality rate in patients who do experience an AAA rupture is higher than 85%.²¹ Not every AAA will rupture, and some clinicians prefer observing the aneurysm over time, especially in the case of aneurysms that are smaller than 2 inches, instead of invasive surgical repair. Younger patients presenting with AAA may be better candidates for surgical repair because the outcomes with repair prior to rupture are generally favorable.²¹

Aortic dissection is a related condition that refers to a separation of the vessel wall, which allows blood to leak between the layers of the vessel. This further damages and weakens the vessel, and patients with an aortic dissection are at an even greater risk of rupture.²¹ Regardless of the clinical course prescribed after a diagnosis of AAA, patients are encouraged to adopt a more healthy lifestyle that includes smoking cessation, exercise, healthy diet, and adequate blood pressure control, to reduce the risk of future clinical events.²¹

The following case discusses a patient case involving an AAA.

Case 5: Abdominal Aortic Aneurysm
Duane Troxler, RT(R)

Background
A 56-year-old Caucasian male presented to an emergency department (ED) with abdomen pain. Palpitation of the abdomen discovered arterial flow. The ED doctor ordered a CT scan to rule out an abdominal aortic aneurysm.

Patient Preparation
A quick blood workup was done to check kidney function (blood urea nitrogen and creatinine). The patient's age, creatinine level, and ethnicity were then used to generate a glomerular filtration rate (GFR). Hospital policy requires CT technologists to get doctor or radiologist approval to administer IV contrast if the patient's GFR is less than 60 mL/min/1.73 m². In this case, a 20-gauge IV was started earlier in the ED by a nurse, and the patient was already on a saline drip. No oral contrast was administered.

Examination Procedure
The power injector was loaded with 100 mL of IV contrast (iopamidol) and 55 mL of saline. The patient was placed on the examination table supine feet first. A preset protocol on the 16-slice CT scanner was selected for the chest/abdomen/pelvis without and with IV contrast. The patient was positioned within the scanner, centered mid-sagittal and just above the sternal notch. One scout image was taken—a coronal view. A scan was then planned from just above the aortic arch and past the bifurcations of the iliac arteries. Two reconstructions were programmed for without and with contrast according to the established site radiologist protocol:

• Reconstruction #1: Soft tissue algorithm, 5-mm slices, 5-mm intervals, and a window/level of 400/40
• Reconstruction #2: Soft tissue algorithm, 3-mm slices, 2-mm intervals, and a window/level of 400/40

The monitoring slice was positioned below the diaphragm. The patient was moved to the superior scan position and the scan without contrast was started and completed. The patient's IV was tested with saline in a 10-mL syringe. Then the power injector was connected to the patient's IV and tested again with 25 mL of saline through the power injector. The patient was moved into position for the monitoring slice, and then 1 axial slice was taken. A region of interest (ROI) was set to the abdominal aorta. The scanner and contrast injector were started at the same time. After a 10-second delay the scanner did the first scan at the preset location. The CT scanner continued scanning until the ROI reached 100 Hounsfield units (HU). When the ROI reached 100 HU, the CT scanner moved the patient to the superior position and started and completed the contrast study. The patient was then disconnected from the power injector and returned to the ED. Two reformats were obtained from the 3-mm x 2-mm contrast series: a coronal and sagittal with 5-mm slices at 5-mm intervals. The complete study was then sent to picture archiving and communication systems for reading.

Findings
Upon review of the CT scans (Figure 6), a large abdominal aortic aneurysm extends from just below the level of the renal arteries to the aortic bifurcation. The aneurysm measures 8 cm in greatest AP diameter and approximately 15 cm in length. A large retroperitoneal hematoma is present, predominantly on the right. This measures up to 6 cm in thickness and extends over 16 cm from midline to the right flank. No active extravasation is identified, but the hematoma is consistent with a leaking aneurysm or rupture.

Discussion
The normal diameter of the infrarenal aorta is approximately 2.3 cm in men and 1.9 cm in women. When the infrarenal aorta grows to more than 50% of its normal size, it is called an aneurysm.²¹ While it is known that an AAA is caused by a degenerative process of the aortic wall, the exact cause of this degeneration is not known. The AAA is most commonly diagnosed in older individuals (aged >60 years), and more so in men and smokers. Abdominal aortic aneurysm is uncommon in people of African, Asian, and Hispanic descent.²²

Case Summary
The patient complained of increasing abdominal pain after the study. He was rushed to another facility for surgery, where the aneurysm was repaired with an aortobiexternal iliac graft.

Imaging Liver Lesions
The liver is the largest glandular organ in the body, weighing approximately 1200 to 1500 g and representing approximately one-fiftieth of total adult body weight.²³ The liver is protected by the ribs and is separated into right and left lobes. The right lobe is further separated into the caudate and quadrate lobes. The liver receives a blood supply from 2 sources, including the portal vein, which supplies venous blood from the intestines and spleen, and the hepatic artery, which carries a supply of arterial blood.²³ The liver is a multipurpose, vital organ that has a wide range of functions. These include the processing of used blood cells; detoxification; and the excretion of cholesterol, steroid hormones, certain vitamins, and drugs.²⁴ Due to the high prevalence of benign focal hepatic lesions in adults, liver lesion characterization is an important objective of diagnostic imaging.

Benign tumors of the liver include hepatocellular adenoma, focal nodular hyperplasia, nodular regenerative hyperplasia, and cavernous hemangioma (hepatic venous malformation). These benign masses can be difficult to diagnose and differentiate from malignant tumors.

Common malignant tumors include hepatocellular carcinoma, which is sometimes associated with hepatitis B or hepatitis C infection, and metastases from other organs.²⁵ The American College of Radiology Appropriateness Criteria provide the clinical situations for variant analysis outlined in Table 2.²⁶ A diagnostic review of hemangioma of the liver is presented in the following case.

Case 6: Hemangioma of the Liver
Wilma Steiner and Patty Johnson

Background
The patient is a 51-year-old male with a history of lesions on his liver. His liver function test was abnormal. A prior CT of his abdomen with 125 mL of ioversol demonstrated numerous abnormalities within the liver, possibly representing partial pacified hemangiomas. There is no history of cancer or surgery.

Patient Preparation and Examination Setup
The patient arrived in the MRI department and was given a gown to change into. The patient's history was taken and the MRI technologist screened the patient for metal objects and checked for any MRI contraindications. The patient also filled out an MRI screening questionnaire. He was then informed of the risks of IV contrast and signed a contrast consent form.

The examination was performed on a 1.5-Tesla (T) scanner. The patient was placed supine, feet first on the scanning table. A flex body array coil was placed anteriorly and a spine coil was placed posteriorly. Headphones were given to the patient for communication and hearing protection. An IV was started and the scan was performed first without contrast. Then 20 mL of gadoversetamide was injected and the scan was performed again.

Examination Parameters
The following sequences were performed (Figure 7):

• Axial T1-weighted in and out of phase MRI
• Axial and coronal T2-weighted half-Fourier acquisition single-shot turbo spin echo
• 3-dimensional (3D) volumetric interpolated breath hold sequence axial T1-weighted MRI; pre-contrast, post-contrast, and immediate; scans 2 minutes and 5 minutes post-contrast
• 3D-volume coronal T1, 5 minutes and axial T1-weighted fat saturated image

Findings and Discussion
Three hemangiomas demonstrated within the liver with numerous tiny sub-centimeter simple-appearing cysts. The appearance of the numerous hepatic tiny cysts could be consistent with multiple biliary hamartomas. These are benign tumors of mature cell and tissue.

Case Summary
Hemangiomas, which are composed of masses of blood vessels, are the most common benign tumor affecting the liver. These tumors are reported in 2% of the population but may be as high as 7%.^27,28 Women are more prone to get these tumors and the ratio from female to male is 4:1 to 6:1. The age of diagnosis is usually between 30 to 50 years old. The origin of these tumors is yet unknown but it is suspected that they are congenital and may be inherited. Oral contraceptives and steroids may accelerate the growth of hemangiomas. ²⁷

Patients normally present with no symptoms, but if they do have any, they may experience pain, nausea, or enlargement of the liver. Hemangiomas are usually discovered when the liver is imaged for some other reason or upon autopsy.^27,28 Usually a biopsy of these tumors is not done due to the risk of bleeding. Most hemangiomas do not require any treatment unless they are very large, and then they may be surgically removed.²⁹ At this time, there is no way to reduce the size or eliminate hepatic hemangiomas.

Imaging of Abdominal or Pelvic Trauma
Traumatic injury involving the abdomen or pelvic can be life-threatening, often due to the risk of internal hemorrhage. Therefore, a primary goal in imaging patients who present with abdominal or pelvic trauma is to search for the presence of any internal hemorrhage or other immediate life-threatening conditions. Once the patient has been stabilized and bleeding has been controlled, patients need to be assessed with a more selective imaging protocol for other internal injuries that could result in late complications, such as infection. Indeed, the posttraumatic mortality peaks in the first hours following the traumatic event and then again at approximately three weeks. This late mortality risk is usually related to infection or multiorgan failure.³⁰

The following case discusses a patient presenting with a pelvic fracture after a fall in the home.

Case 7: Renal Cell Carcinoma
Terry Duggan-Jahns, RT(R)(CT)(MR)(M)

Background
The patient is a 68-year-old female with a history of polycystic liver disease, left renal cell carcinoma status and post left nephrectomy approximately 15 years ago. The patient also reported prior splenectomy due to a traumatic injury 15 years ago as well. The patient has had multiple yearly follow-up ultrasound examinations. An abdominal ultrasound was performed that demonstrated a large mass within the left upper quadrant, liver cysts and right kidney cysts. Given the history of renal cancer, a CT abdomen and pelvis study with and without IV contrast was recommended by the radiologist to further evaluate the left upper quadrant mass. The patient denied any other symptoms.

Patient Preparation
The patient was given 250 mL of oral barium to drink the night before her examination and was instructed to drink an additional 250 mL 1 hour prior to her examination appointment time.

Blood work for blood urea nitrogen and creatinine levels were performed prior to her examination following the ACR IV Contrast Safety guidelines protocol. Due to the patient having only 1 kidney and after consultation with her nephrologist a "high-risk" hydration protocol was followed to prevent contrast-induced nephrotoxicity (CIN). Risk factors for CIN include diabetes mellitus, a history of kidney disease, calculated creatinine clearance, or calculated GFR less than 60 mL/min, past or current history of heart failure, history of multiple myeloma, exposure to IV radiocontrast media within the past 72 hours, and the use of long-term nonsteroidal anti-inflammatory agents. For at-risk patients, clinicians must use their judgment to determine if imaging modalities that do not involve contrast media are an acceptable alternative to contrast studies. It was felt that this patient would benefit from having IV iodinated contrast media and that the hospital's high-risk hydration protocol would be warranted prior to receiving IV CT contrast for the examination.

The patient arrived to inpatient radiology 1 hour prior to her scheduled CT appointment to receive sodium bicarbonate 150 mEq in 1000 mL 5% dextrose in water, infused at 3 mL/kg for 1 hour, starting at 1 hour pre-procedural (or contrast media administration), followed by 1 mL/kg/hour during the procedure and for at least 6 hours post procedure.

Examination Procedure
The patient was placed supine on the CT table. The patient was scanned from the xiphoid process to the symphysis pubis by 5-mm intervals on a CT 64 slice scanner. Volumetric images were obtained of the abdomen and pelvis before and after the IV injection of 100 mL of iopamidol (Figures 8-10).

 

Case Summary
Innumerous cysts were found in the liver, with sizes ranging from less than 5 mm to greater than 5 cm. These cysts occupied at least 80% of the liver. There were several right renal cysts ranging from 5 mm to 2.5 mm in size. There was a large vascular mass within the left upper quadrant that measured 19 cm cranial to caudal, 13 cm medial to lateral, and 13 cm anterior to posterior. It was felt that this mass was very unusual and could potentially represent a sarcoma. It could also be related to the patient's renal cell carcinoma. A recurrent renal neoplasm was felt to be less likely. Blood supply to this mass originated from the superior mesenteric artery and was drained by the superior mesenteric vein.

Case Discussion
Renal cell carcinoma is the most common primary renal malignant neoplasm in adults, representing approximately 90% of renal tumors and 2% of all adult malignancies. Men are at a higher risk of renal cell carcinoma than women. Renal cell carcinoma is more common with increasing age; the most common group to develop renal cell carcinoma are patients aged 55 to 84 years.

The potential morbidity and mortality associated with renal cell carcinoma depends on the stage of the disease at diagnosis. Patients with small, non-metastatic masses have a better prognosis than those with metastatic disease at presentation. Increasing size the primary lesion also affects outcome, as larger masses tend to be of a higher tumor grade and are more likely to metastasize. Masses with poor margins or necrosis also tend to be of a higher tumor grade. Survival rates in T1 renal cell carcinoma masses in which resection is attempted is 95% and 91% at 5 years and 10 years, respectively. Meanwhile, unresectable tumors are associated with a 5-year survival rate of less than 20%.³⁰

Case Summary
Recommendations: Possible CT guided biopsy to determine left upper quadrant pathologt and follow up CT kidney study within 6 to 12 months to evaluate the single right renal cyst enhancing septation.

Imaging of Abdominal or Pelvic Trauma
Traumatic injury involving the abdomen or pelvic can be life-threatening, often due to the risk of internal hemorrhage. Therefore, a primary goal in imaging patients who present with abdominal or pelvic trauma is to search for the presence of any internal hemorrhage or other immediate life-threatening conditions. Once the patient has been stabilized and bleeding has been controlled, patients need to be assessed with a more selective imaging protocol for other internal injuries that could result in late complications, such as infection. Indeed, the post-traumatic mortality peaks in the first hours following the traumatic event and then again at approximately 3 weeks. This late mortality risk is usually related to infection or multiorgan failure.³¹

The following case discusses a patient presenting with a pelvic fracture after a fall in the home.

Case 8 Pelvic Fracture
Duane Troxler, RT(R)

Background
An 88-year-old female came to the ED at approximately 1 pm after falling in her kitchen at home that morning. She had a head injury with laceration and complained of right hip pain. X rays were taken of the right hip and fractures were noted by the radiologist at the right superior and inferior pubic rami medially. At approximately 3 pm the patient had an episode with deviation of her eyes to the left and a tonic-like behavior involving her upper extremities. The doctor ordered a second head CT, because the patient was taking clopidogrel and felt her risk of intracranial hemorrhage was greater than average. The head CT came back negative. The doctor re-examined the patient and revealed a soft non-distended abdomen, non-palpable peripheral pulses, and systolic blood pressure in the 70s. A bolus of sterile normal saline was started to reestablish a blood pressure. A CT of the abdomen and pelvis was ordered to look for an additional injury.

Patient Preparation
Because the patient was coming from the ED, the only preparation was an IV access for IV contrast. Examination Procedure
The procedure was done on a 16-slice CT scanner. The patient was placed on the CT table supine feet first. She was moved into the scanner and centered mid-coronal and at the xiphoid process. Two scout scans were taken-coronal and sagittal views. The final examination was planned from these scout scans—from above the diaphragm to past the pubis symphysis. Two reconstructions were done: one at 5 mm x 5 mm and the other 2.5 mm x 2.5 mm using a soft tissue algorithm with a window/level of 400/40. Two reformats were done: one in a coronal view and the other in a sagittal view. Both reformats were done at 5 mm x 5 mm.

Findings
Findings included a comminuted right pelvic fracture involving the iliac wing (Figures 11 and 12), as well as the superior and inferior pubic rami with evidence of active extravasation at the level of the inferior pubic ramus (Figure 12). Large amounts of blood tracking into the lateral abdominal wall, as well as into the retroperitoneum, were noted (Figure 13).³²

Discussion
Blackmore et al of Harborview Medical Center conducted a study that gathered data from 759 blunt trauma patients who sustained pelvic fractures.³³ Up to 52% of ED patients with pelvic fractures developed shock due to hemorrhage. The study showed a mortality of 13%, 55% of patients received blood transfusions, and 34% of patients received 6 or more units of blood in the first 72 hours.³²

Case Summary
The patient was transferred to another facility for further care. When the patient arrived at the new facility, they were unable to get a blood pressure because she was so hypotensive. IV fluids and blood products were infused. A central-line catheter was then started. The patient tolerated the central-line procedure well.

Conclusions: The Evolving Role of CT and MRI in Abdominal Imaging
Radiologic technologists should be intimately familiar with the presentations discussed in these cases, and should be ready to implement current CT and MRI modalities to the diagnostic assessment of similar patients. As illustrated in these clinical cases, both CT and MRI play critical roles in a wide variety of abdominal imaging applications. These range from patients presenting with chronic disease or possible malignancies, to patients who have experienced trauma affecting the abdomen or pelvis. Patients will continue to benefit from CT and MRI modalities as the field advances and diagnostic systems are introduced that offer the ability to provide diagnostic services with ever-increasing accuracy and more rapid results. As new technology is introduced, radiologic technologists should likewise be prepared to advance their personal knowledge of the most current techniques to provide abdominal imaging services and work with radiologists and other clinicians to deliver the most effective clinical care to their patients.

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