finals Flashcards by mad bxnny

Patients with severe WHAT should not receive I.V. contrast; discuss other possible imaging studies (US, MR, non-contrast CT, etc.) with clinicians.

anaphylaxis, cardiac or respiratory arrest

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CREATININE CLEARANCE

Obtained in all patients WHAT

≥ 50 y.o. within 30 days of the exam.

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Obtain a creatinine in younger patients with history of renal disease malignancy, chemotherapy within HOW MANY DAYSdays or other potentially nephrotoxic drugs, paraproteinemia syndrome (multiple myeloma) collagen vascular diseases (lupus), diabetes

within 30 days

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Patients with increasing creatinine over a short period of time (days) should not receive I.V. contrast even if creatinine is < WHAT These patients are likely going into renal failure.

< 1.5

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Patients with end stage renal failure who are on regular dialysis may receive non - ionic I.V. contrast, preferably shortly before dialysis. Those requiring only WHAT should not receive I.V. contrast.

intermittent dialysis (renal insufficiency

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If CT: oral and IV contrast at WHATrecons, mA of 175 or less if possible (150 mA is usually ok)

5mm with 2.5 mm recons,

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If CT: oral and IV contrast at 5mm with 2.5 mm recons, mA of WHATif possible (150 mA is usually ok)

mA of 175 or less

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SCAN RANGE (ROI/FOV):

FOR THE BRAIN AND CALVARIUM CT:
Scan range starting at WHAT; ending at vertex of the skull using 5mm to 7mm ST

base of the skull

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SCAN RANGE (ROI/FOV):

FOR THE BRAIN AND CALVARIUM CT:
Scan range starting at base of the skull; ending at WHAT using 5mm to 7mm ST

ending at vertex of the skull

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SCAN RANGE (ROI/FOV):

FOR THE BRAIN AND CALVARIUM CT:
Scan range starting at base of the skull; ending at vertex of the skull using HOW MANY ST

5mm to 7mm ST

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FOR THE TEMPORAL BONE SCAN (INNER EAR);
from the WHATthrough the mastoid tip, ST <0.5mm

arcuate eminence (the summit of the temporal bone)

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FOR THE TEMPORAL BONE SCAN (INNER EAR);
from the arcuate eminence (the summit of the temporal bone) through the WHAT

mastoid tip,

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FOR THE TEMPORAL BONE SCAN (INNER EAR);
from the arcuate eminence (the summit of the temporal bone) through the mastoid tip, ST HOW ANYmm

FOR THE TEMPORAL BONE SCAN (INNER EAR);
from the arcuate eminence (the summit of the temporal bone) through the mastoid tip, ST <0.5mm

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Works in tandem with an X-ray source to
measure the X-rays that pass through the body.

Detector

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The process of creating a cross- sectional tomographic plane of any part of the
body

Computed Tomography

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A mathematical operator that plays a key role in various areas such as medical
imaging, tomography, and even in signal processing

Radon Transforms

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Central circular opening that allows the patient to pass through it, usually lying on a motorized table that moves them through the scanner

Gantry Aperture

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The thickness of each individual cross-sectional image obtained during the scan

SLICE THICKNESS

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The measurement of how far apart two objects must be before they can be seen as separate details in the image

Resolution

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The ability to differentiate between small differences in density within the image.

Contrast Resolution

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The average source detector distance for modem or advanced CT scans

44” (110cm)

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These machines are only capable of producing axial images

Cat Scanner

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Collimator functions that ensure that the X-rays are directed only to the specific region of interest, helping to minimize exposure to surrounding tissues.

Beam Shaping

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Determines the total radiation dose delivered to the patient and affects image quality

MAS

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Each __ in the image corresponds to the volume of tissue in the body section being imaged

Pixel

Uses mathematical algoritms to convert raw data into usable images.

Image Resolution

Distortion or error in the image that doesn't represent the true anatomy or pathology of the patient.

Artifacts

The relationship between patient couch movement and x-ray beam width

Pitch

An array of numbers arranged in a grid of rows and columns

Matrix

. Consist of pressurized Gas-filled lonization chambers and tungsten electrode plate

Gas filled Detector

Tomo in the word Tomography comes from the Greek word _ which means to cut.

Tomos

How long can the first CAT Scanner produce a single sectional image

9 days

The raw data the computer receive after the detectors collect the transmitted x-rays is also called _?

Projection

His work helped in the mathematical methods that enable the inversion of the Radon transform, which is essential for reconstructing images from the projections obtained in CT scans

Alessandro Vallebona

He used computers to process and reconstruct images from X-ray data, a breakthrough that laid the foundation what would later become the moder CT scanner.

William Oldendorf

An electrical engineer who invented the first CT Scan machine for EMI Ltd. Company

Godfrey Hounsfield

He expanded the diagnostic capabilities of CT by his development of the first whole-body scanner

Robert Ledley

Detector parameter which is the efficiency to convert light or ions to digital signal

Conversion Efficiency

Consists of an x-ray source emitting finely collimated x-ray beam and a single detector both moving synchronously i a translate or rotate mode or a combination of both.

Scanner

It is a critical component that generates X-rays, which are used to create cross-sectional images of the body.

X-ray tube

This refers to the first full-scale commercial unit installed in 1971

Brain Tissue Scanner

Uses a flying electron beam, steered electromagnetically and to hit one of the anode strips that encircle the patient. No moving parts, therefore very fast

5th Generation CT

A CT generation that can produce High-Definition topography and excels in MPR and 3D reconstruction

7th Generation CT

These are described as unintended optical density on a radiograph

Artifacts

Tissue density values that represent the linear attenuation coefficient equivalent of various tissues

CT Number/Hounsfield Unit

The part of beam falling onto a single detector

RAY

A traditional relatively fast algorithm that uses a convolution fitter to reduce blurring in the image

Filtered back Projection (FBP)

Artifacts that are caused by a group of channels or views deviating gradually from the true measurement

Shading

Hounsfield Unit analyzation by use of a bar graph

Histogram

The thickness of the images that we see on the screen is called

Reconstruction slice thickness

Deletion of unwanted parts from reconstructed image

Suppression

A special CT Pre-patient equipment that shapes collimated beam for uniformity

bow-tie filter

Used for showing true dimensions by moving a narrow orthogonal beam of x-rays along the length of the structure being measured

Scanogram

Described as the X-ray tube and detectors rotate the patient moves through the scarniner in small increments, allowing for the creation of multiple slices through different parts of the body

Rotational Acquisition

The process involves converting the raw projection dáta into interpretable images using specialized algorithms

Reconstruction of Data

Which of the following geometric factors should be considered to improve improving image quality and detection

Smaller detector

CT number/Hounsfield Unit of bone

1000HU

The are the effects of selecting larger Section Interval and Thickness, except

Decreased Exposure Factors

Scan field size or FOVs must be set to accommodate the size of the part under examination FOVs for small bodies is commonly set at ____.

● 35cm

Scanograms are taken before the main CT scan for the following purposes, except

Adjust exposure factors

Use of cursor that is to identify and mark specific structures, lesions, or areas of interest within the CT scan images

Locating features.

The Hounsfield scale or CT numbers is a Quantitative scale that is used to describe

Radiodensity

All other patients should be premedicated prior to procedure except,

severe contrast allergies

An example of severe contrast reaction

unresponsiveness

For CT for a Pregnant Woman, contrast examinations should include oral and IV contrast at recons.

5mm with 2.5 mm

Head CT Scan range starts from the

Base of the skull

Stage of brain hemorrhage characterized by hyperdense intensity on image.

Acute

Bone

0.5mm

For Contrast examinations injection of contrast should be done

Before plain series

Common clinical findings for Head CT includes the following, except.

Meningitis

Instructions for respiration in Neck CT

Suspended in expiration with no swallowing

Neck CT Scan Range usually starts at and end at the thoracic inlet.

Midsphenoid

Which of the following is not an Indication of CTA Pulmonary Angiography

Abdominal Aoatic Aneurysm (AAA)

For chest/thoracic CT; Scan range should start from the lung apex to the

most inferior border of the diaphragm

Usual slice thickness used for chest/thoracic Ct scanning is

3-10mm

Whole Abdomen and Stonogram examination that UT stone, retroperitoneal hematoma

Without oral or IV contrast (Plain study)

Scan range (FOV/ROI) for Abdominopelvic scan usually ends at

Sympysis pubis

Patient Bowel Preparations for Abdominopelvic scans have NPO a night prior to procedure starting at

12 midnight

For oral contrast Preparations for Abdominopelvic scans, ml of Barium should be given 60 mins prior to scanning.

250

Patients who may have a bowel perforation should be given dilute

hypaque

An enhanced CT technique mostly used to evaluate liver lesions by acquiring images at different time points, or phases, following the administration of a contrast.

Triphasic CT

finals Flashcards

(81 cards)