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Flashcards in BASIC IMAGING - CT,MRI,Plain Film Deck (44)
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1

The measure of the potential adverse health effects of ionizing radiation in sieverts (Sv) is known as:

a. radiation exposure.

b. absorbed dose.

c. equivalent dose.

d. effective dose.

e. relative radiation levels.

d. Effective dose. The distribution of energy absorption in the human body will be different based on the body part being imaged and a variety of other factors. The most important risk of radiation exposure from diagnostic imaging is the development of cancer. The effective dose is a quantity used to denote the radiation risk (expressed in sieverts) to a population of patients from an imaging study.

2

The relative radiation level associated with abdominal computed tomography (CT) without and with contrast is:

a. none. b. minimal, less than 0.1 mSv. c. low, 0.1 to 1.0 mSv. d. moderate, 1 to 10 mSv

e. High, 10 to 100 mSv.

e. High, 10 to 100 mSv. The average person living in the United States is exposed to 6.2 mSv of radiation per year from ambient sources, such as radon, cosmic rays, and medical procedures, which account for 36% of the annual radiation exposure (NCRP, 2012). The recommended occupational exposure limit to medical personnel is 50 mSv per year (NCRP, 2012). The effective dose from a three-phase CT of the abdomen and pelvis without and with contrast may be as high as 25 to 40 mSv.

3

Autonomic dysreflexia, also known as hyperreflexia, means an _____ that can result in an abrupt onset of excessively high blood pressure. Persons at risk for this problem generally have spinal cord injury ____.

Autonomic dysreflexia, also known as hyperreflexia, means an overactivity of the autonomic nervous system that can result in an abrupt onset of excessively high blood pressure. Persons at risk for this problem generally have spinal cord injury level above T6. Autonomic dysreflexia can develop suddenly, is potentially life threatening, and is considered a medical emergency. If not treated promptly and correctly, it may lead to seizures, stroke, and even death

4

Radiation exposure diminishes as the square of the distance from the radiation source. An exposure of 9 mSv at 1 foot from the source would be how much at 3 feet from the source?

a. 0.09 mSv b. 1 mSv c. 3 mSv d. 9 mSv e. 27 mSv

b. 1 mSv. Maintaining the maximum practical distance from an active radiation source significantly decreases exposure to medical personnel

5

Patients with type 2 diabetes mellitus on metformin may have an accumulation of the drug after administering ______, resulting in biguanide lactic acidosis presenting with vomiting, diarrhea, and somnolence. This condition is fatal in approximately ____of cases (Wiholm, 1993). a Biguanide lactic acidosis is ____ in patients with normal renal function.

Patients with type 2 diabetes mellitus on metformin may have an accumulation of the drug after administering intravascular radiologic contrast medium (IRCM), resulting in biguanide lactic acidosis presenting with vomiting, diarrhea, and somnolence. This condition is fatal in approximately 50% of cases (Wiholm, 1993). a Biguanide lactic acidosis is rare in patients with normal renal function. Consequently in patients with normal renal function and no known comorbidities, there is no need to discontinue metformin before IRCM use, nor is there a need to check creatinine following the imaging study.

6

The mechanism of action associated with severe idiosyncratic anaphylactoid (IA) reactions is an ____ to the contrast media. The IA reactions are most concerning because they are potentially fatal and can occur without any predictable or predisposing factors. Approximately 85% of IA reactions occur during or immediately after injection of IRCM and are more common in patients with a prior __; patients with __, ___, ___, ___; and ___

immunoglobulin E (IgE) antibody reaction, prior adverse drug reaction to contrast media; patients with asthma, diabetes, impaired renal function, or diminished cardiac function; and patients on beta-adrenergic blockers

7

Rapid administration of ____ is the treatment of choice for severe contrast reactions. It can be administered intravenously (IV) ____ or ___ slowly into a running IV infusion of saline and can be repeated every 5 to 15 minutes as needed. If no IV access is available, the recommended intramuscular dose of epinephrine is ____ injected intramuscularly in the ____

Rapid administration of epinephrine is the treatment of choice for severe contrast reactions. Epinephrine can be administered intravenously (IV) 0.01 mg/kg body weight of 1: 10,000 dilution or 0.1 mL/kg slowly into a running IV infusion of saline and can be repeated every 5 to 15 minutes as needed. If no IV access is available, the recommended intramuscular dose of epinephrine is 0.01 mg/kg of 1:1000 dilution (or 0.01 mL/kg to a maximum of 0.15 mg of 1:1000 if body weight is 30 kg) injected intramuscularly in the lateral thigh.

1mg/ml (1:1000) solution for injection (ampoule)

8

Which of the following is NOT a risk factor for developing contrast-induced nephropathy (CIN)? a. Type 2 diabetes mellitus b. Dehydration c. Hypertension d. Ventricular ejection fraction less than 50% e. Chronic kidney disease (CKD) (glomerular filtration rate [GFR] < 60 mL/min)

d. Ventricular ejection fraction less than 50%. The most common patient-related risk factors for CIN are CKD (creatinine clearance <60 mL/min), diabetes mellitus, dehydration, diuretic use, advanced age, congestive heart failure, age, hypertension, low hematocrit, and ventricular ejection fraction less than 40%. The patients at highest risk for developing CIN are those with both diabetes and preexisting renal insufficiency

9

Nephrogenic systemic fibrosis (NSF) is: a. a rare genetic condition exacerbated by the use of gadoliniumbased contrast medium (GBCM). b. immediately evident after exposure to gadolinium in 10% of exposed patients. c. fibrosis of the skin, subcutaneous tissue, and skeletal muscle seen in patients with chronic hypertension exposed to gadolinium contrast medium. d. not seen in patients with GFR greater than 60 mL/min/1.73 m2 . e. mainly seen in dialysis patients exposed to gadolinium contrast medium.

Patients with CKD but GRF greater than 30 mL/min/1.73 m2 are considered to be at extremely low or no risk for developing NSF if a dose of GBCM of 0.1 mmol/kg or less is used. Patients with GFR greater than 60 mL/min/1.73 m2 do not appear to be at increased risk of developing NSF, and the current consensus is that all GBCM can be administered safely to these patients.

10

During a diuretic renal scintigraphy:

 Transit time throughout the collecting system in less than _______ is consistent with a normal, nonobstructed collecting system. A T½ of 10 to 20 minutes shows mild to moderate delay and may be a _______. The patient’s perception of pain after diuretic administration can be helpful for the treating urologist to consider when planning surgery in the patient with middle to moderate obstruction. A T ½ of greater than 20 minutes is consistent with a ______

 Transit time throughout the collecting system in less than 10 MINUTES is consistent with a normal, nonobstructed collecting system. A T½ of 10 to 20 minutes shows mild to moderate delay and may be a MECHANICAL OBSTRUCTION. The patient’s perception of pain after diuretic administration can be helpful for the treating urologist to consider when planning surgery in the patient with middle to moderate obstruction. A T ½ of greater than 20 minutes is consistent with a HIGH-GRADE OBSTRUCTION

11

Positron emission tomography (PET):

Has a higher diagnostic accuracy than CT for ______ cancer following chemotherapy.

Has a higher diagnostic accuracy than CT for seminoma and nonseminoma testis cancer following chemotherapy. There are data on the use of PET/CT in testis cancer, where PET/CT was found to have a higher diagnostic accuracy than CT for staging and restaging in the assessment of a CT-visualized residual mass following chemotherapy for seminoma and nonseminomatous germ cell tumors

12

What is the minimum estimated GFR for use of gadolinium-based contrast agents?

a. Less than 30 mL/min/1.73 m2 b. Greater than 50 mL/min/1.73 m2 c. Greater than 35 mL/min/1.73 m2 d. Greater than 30 mL/min/1.73 m2 e. There are no restrictions for patients with renal insufficiency

d. Greater than 30 mL/min/1.73 m2 . NSF occurs in patients with acute or chronic renal insufficiency with a GFR less than 30 mL/min/1.73 m2

13

High signal on T2-weighted images is _______. Fluid exhibits a ______ on T1-weighted images

bright, low signa

14

MR chemical shift imaging (CSI) for adrenal adenoma takes advantage of which of the following phenomena to aid in the diagnosis?

a. Water and fat within the same voxel signals are canceled out in opposed-phase imaging.

b. Opposed-phase imaging will exhibit a high signal (bright). c. Intracellular lipid content within an adenoma is low.

d. Intravenous contrast is required.

e. All of the above

a. Water and fat within the same voxel signals are canceled out in opposed-phase imaging. MR CSI is performed on T1-weighted images. Opposed-phase imaging will demonstrate a low signal (dark) if fat and water occupy the same voxel. Adrenal adenomas have high intracytoplasmic fat. CSI is performed without the use of intravenous contrast.

15

Oncocytoma typically has been characterized by a central scar. Which other renal lesion may also exhibit a central scar on T2- weighted images? a. Clear cell carcinoma b. Angiomyolipoma c. Chromophobe carcinoma d. Transitional cell carcinoma e. No other renal masses exhibit

. c. Chromophobe carcinoma. Chromophobe carcinoma exhibits a high signal on T2-weighted images.

16

Microscopic intracytoplasmic lipids have been found in 59% of____, which allows it to be differentiated from other renal cell carcinoma cell types.

Microscopic intracytoplasmic lipids have been found in 59% of clear cell carcinomas, which allows it to be differentiated from other renal cell carcinoma cell types.

17

Multiparametric imaging of the prostate consists of anatomic and functional sequences. Match the correct pair. a. Anatomic: Diffusion-weighted imaging

b. Functional: T1- and T2-weighted images

c. Anatomic: Dynamic contrast enhanced sequences

d. Functional: Apparent diffusion coefficient maps

e. All of the above

d. Functional: Apparent diffusion coefficient maps. Multiparametric MRI refers to the use of anatomic sequences (T1- weighted images, T2 triplanar [axial, sagittal, and coronal] images) and functional sequences (diffusion-weighted imaging/apparent diffusion coefficient maps, dynamic contrast-enhanced MRI, spectroscopy). The combined approach has reported negative and positive predictive values to be greater than 90% in detecting prostate cancer.

18

Absorbed dose for therapy is measured in units called gray (Gy); 1 rad =____, or 1 centigray (cGy) = 1 rad.

Absorbed dose for therapy is measured in units called gray (Gy); 1 rad = 0.01 Gy, or 1 centigray (cGy) = 1 rad.

19

The amount of energy absorbed by a tissue for diagnostic purposes is referred to as the ___  and is measured in sieverts (Sv). Exposure of the ___ and ___ to radiation has a more significant biologic impact than exposure of other parts of the body. The occupational safety limit is ___. Exposure time during fluoroscopy should be minimized by the use of short bursts of fluoroscopy; positioning the image intensifier as close to the patient as feasible substantially reduces scatter radiation.

The amount of energy absorbed by a tissue for diagnostic purposes is referred to as the EQUIVALENT DOSE and is measured in sieverts (Sv). Exposure of the eyes and gonads to radiation has a more significant biologic impact than exposure of other parts of the body. The occupational safety limit is 50 mSv. Exposure time during fluoroscopy should be minimized by the use of short bursts of fluoroscopy; positioning the image intensifier as close to the patient as feasible substantially reduces scatter radiation.

20

Patients at high risk for adverse allergic reactions should be medicated with ___, given ___ hours before the injection of contrast media, as well as antihistamines

Patients at high risk for adverse allergic reactions should be medicated with STEROIDS, given 12 to 24 hours before the injection of contrast media, as well as antihistamines

21

For retrograde pyelography, it is useful to dilute contrast media by_____, which facilitates identifying filling defects in the collecting system. There is a ____ of contrast reactions in patients in whom a retrograde or loopogram is performed.

For retrograde pyelography, it is useful to dilute contrast media by half with sterile saline, which facilitates identifying filling defects in the collecting system. There is a low risk of contrast reactions in patients in whom a retrograde or loopogram is performed.

22

TcDTPA is primarily filtered by the ___. It is a good agent to assess___.

it less useful in ___ and ___

TcDTPA is primarily filtered by the glomerulus. It is a good agent to assess renal function.

it is less useful renal failure and decreasing GFR

23

Because TcDMSA is both filtered by the ___ and secreted by the ____, it localizes in the___ and is a good agent for assessing ___ and ___

Not useful for visualizing ureters and collecting system

Because TcDMSA is both filtered by the glomerulus and secreted by the proximal tubule, it localizes in the renal cortex and is a good agent for assessing cortical scarring and ectopic renal tissue

24

TcMAG3 is cleared mainly by ____; it has a limited ability to access renal function.

It is the imaging of choice with ____ and ___

TcMAG3 is cleared mainly by tubular secretion; it has a limited ability to access renal function.

It is the imaging of choice for renal insufficiency and urinary obstruction

25

A positive bone scan is ____ for cancer. Moreover, the volume of cancer ___ be quantitated on bone scan. Patients with widely metastatic disease may have diffuse uptake (hyper scan) and no discrete lesions.

A positive bone scan is not specific for cancer. Moreover, the volume of cancer cannot be quantitated on bone scan. Patients with widely metastatic disease may have diffuse uptake (hyper scan) and no discrete lesions.

26

__, __ and __ have been used as imaging agents for PET scans.

Glucose, choline, and amino acids have been used as imaging agents for PET scans.

27

18F-fluorodeoxyglucose (FDG) is used as an imaging agent in PET scanning and takes advantage of the fact that tumors have increased _____ and decreased ___. This scan is useful in ____, particularly ___, in determining residual viable tumor following chemotherapy

18F-fluorodeoxyglucose (FDG) is used as an imaging agent in PET scanning and takes advantage of the fact that tumors have increased glycolysis and decreased dephosphorylation. This scan is useful in testicular germ cell tumors, particularly seminomas, in determining residual viable tumor following chemotherapy

28

The Hounsfield units scale assigns a value of ___ Hounsfield units for air. Dense bone is assigned a value of ___ Hounsfield units, and water is assigned __Hounsfield units.

The Hounsfield units scale assigns a value of −1000 Hounsfield units for air. Dense bone is assigned a value of +1000 Hounsfield units, and water is assigned 0 Hounsfield units. 18. With the exception of some indinavir stones,

29

With the exception of some ___, all renal and ureteral calculi may be detected by helical CT.

With the exception of some indinavir stones, all renal and ureteral calculi may be detected by helical CT.

30

The advantage of MRI is the ____ on T1-weighted images. Fluid has a ____ and appears dark on T1- weighted images; on T2-weighted images, fluid has a high signal and appears bright. ___ increases the brightness of T1-weighted images. Hemorrhage within a cyst results in a high signal on T1- weighted images. MRI is the imaging modality of choice for patients with ____

The advantage of MRI is high-contrast resolution of soft tissue on T1-weighted images. Fluid has a low signal and appears dark on T1- weighted images; on T2-weighted images, fluid has a high signal and appears bright. Gadolinium increases the brightness of T1-weighted images. Hemorrhage within a cyst results in a high signal on T1- weighted images. MRI is the imaging modality of choice for patients with iodine contrast allergies.