SEM 3 - Diagnostic imaging wk 4-

missing wk 4 pollev

The primary educational goal of the CT scan lecture is to help PT students (lecture 3 wk 4):

A. Interpret radiology reports independently
B. Understand clinical uses and limitations of advanced imaging
C. Perform CT scans in a clinical setting
D. Memorize all available advanced imaging modalities

Answer: B

Rationale: The lecture emphasizes understanding clinical uses and limitations, not performing or exhaustively memorizing imaging types.

Computed tomography (CT) is BEST described as:

A. A magnetic field–based imaging technique
B. A fusion of radiography and computed image reconstruction
C. A dynamic imaging technique using sound waves
D. A nuclear medicine technique measuring metabolic activity

Correct Answer: B

Rationale: CT combines X-ray radiography with computer-based reconstruction.

How does the CT scanner acquire images of the body?

A. A stationary X-ray beam captures a single image
B. The patient rotates while the detector remains fixed
C. The X-ray tube rotates 360° around the patient
D. Multiple ultrasound probes scan simultaneously

Correct Answer: C

Rationale: The X-ray tube rotates in a circular arc around the patient.

CT images are reconstructed into which type of slices?

A. Coronal slices only
B. Oblique slices only
C. Axial (cross-sectional) slices
D. Three-dimensional volumetric images only

Correct Answer: C

Rationale: CT produces axial/cross-sectional slices, which can later be reformatted.

Typical CT slice thickness ranges from approximately:

A. 0.01–0.1 mm
B. 0.1–10 mm
C. 10–50 mm
D. 1–5 cm

Correct Answer: B

Rationale: The lecture states CT slices are ~0.1 to 10 mm thick, allowing high detail.

Compared to conventional radiographs, CT scans are more sensitive because they:

A. Use contrast agents routinely
B. Provide dynamic imaging
C. Allow visualization in an axial plane
D. Eliminate radiation exposure

Correct Answer: C

Rationale: CT provides additional views (especially axial) not available on plain films.

A major clinical use of CT scanning is:

A. Evaluating ligamentous injuries
B. Identifying metabolic abnormalities
C. Triplane visualization of complex fractures
D. Assessing muscle activation patterns

Correct Answer: C

Rationale: CT excels at complex fracture visualization using multiple planes.

CT and MRI both allow visualization in which three orthogonal planes?

A. Axial, oblique, rotational
B. Coronal, transverse, oblique
C. Sagittal, coronal, axial
D. Longitudinal, transverse, diagonal

Correct Answer: C

Rationale: Both modalities provide sagittal, coronal, and axial views.

CT image contrast is primarily based on differences in:

A. Proton density
B. Radio density of tissues
C. Blood flow velocity
D. Electrical conductivity

Correct Answer: B

Rationale: CT images reflect radio density, producing varying shades of gray.

On a CT scan, which tissue typically appears the MOST white (hyperdense)?

A. Muscle
B. Fat
C. Cortical bone
D. Water

Correct Answer: C

Rationale: Cortical bone has the highest radio density and appears white.

Which structure would appear more gray than cortical bone but denser than muscle on CT?

A. Subcutaneous fat
B. Cancellous bone
C. Air
D. Cerebrospinal fluid

Correct Answer: B

Rationale: Cancellous bone is less dense than cortical bone but denser than soft tissue.

When reviewing CT images, clinicians typically:

A. View a single representative image
B. View images only in the sagittal plane
C. Scroll through a series of images
D. Use only reconstructed 3D models

Correct Answer: C

Rationale: CTs are interpreted by scrolling through multiple slices, not single images.

Viewing CT images challenges PT students MOST because it requires strong knowledge of:

A. Pathophysiology
B. Neuroplasticity
C. Anatomy
D. Exercise prescription

Correct Answer: C

Rationale: The lecture stresses applying anatomy knowledge to image interpretation.

Axial CT images are displayed as if:

A. The viewer is standing at the patient’s head
B. The viewer is looking from the patient’s feet upward
C. The patient is prone
D. The viewer is looking posterior to anterior

Correct Answer: B

Rationale: Axial images are viewed caudo-cephalad, as if standing at the feet.

Sagittal CT images are conventionally viewed from:

A. Right to left
B. Anterior to posterior
C. Left to right
D. Inferior to superior

Correct Answer: C

Rationale: Sagittal images are viewed left → right.

The grayscale appearance on CT images follows similar principles to plain radiographs for which substances?

A. Bone, muscle, ligament, tendon
B. Air, fat, water, bone
C. Blood, fat, nerve, bone
D. Cartilage, fat, air, muscle

Correct Answer: B

Rationale: CT grayscale mirrors radiographs for air, fat, water, and bone.

In clinical practice, CT is MOST commonly the imaging modality of choice for evaluating:

A. Ligamentous injury
B. Muscle strain
C. Bone pathology
D. Peripheral nerve injury

Correct Answer: C

Rationale: CT is best for bone, while radiographs are typically first-line.

When evaluating bone pathology, the typical imaging sequence is:

A. CT → MRI → Radiograph
B. MRI → CT → Radiograph
C. Radiograph → CT
D. CT → Radiograph

Correct Answer: C

Rationale: Plain radiographs are usually first-line; CT is used when more detail is needed.

Which of the following is an indication where CT would be preferred over plain radiographs?

A. Mild muscle strain
B. Subtle or complex fracture
C. Tendinopathy
D. Peripheral neuropathy

Correct Answer: B

Rationale: CT excels at detecting subtle and complex fractures.

CT is particularly useful for evaluating ALL of the following EXCEPT:

A. Degenerative spinal changes
B. Spinal stenosis
C. Intervertebral disc pathology
D. Muscle fiber recruitment

Correct Answer: D

Rationale: CT evaluates structural anatomy, not muscle activation.

A coronal CT image of the lumbar spine showing abnormal lateral curvature is MOST consistent with:

A. Kyphosis
B. Lordosis
C. Scoliosis
D. Spondylolisthesis

Correct Answer: C

Rationale: Coronal plane curvature indicates scoliosis.

Degenerative spinal changes seen on CT would MOST likely include:

A. Increased muscle density
B. Loss of neural firing
C. Osseous and joint changes
D. Altered blood flow

Correct Answer: C

Rationale: CT highlights bony and joint degeneration well.

Which of the following is an advantage of CT compared to MRI?

A. No ionizing radiation
B. Better soft tissue contrast
C. Less expensive
D. Superior ligament visualization

Correct Answer: C

Rationale: CT is less expensive and faster than MRI.

Which factor makes CT more tolerable for some patients compared to MRI?

A. Lower radiation dose
B. Less claustrophobic design
C. Superior image resolution
D. Absence of contrast agents

Correct Answer: B

Rationale: CT scanners are typically less claustrophobic.

A major disadvantage of CT imaging is:

A. Poor visualization of bone
B. Long imaging time
C. High ionizing radiation exposure
D. Inability to image soft tissue

Correct Answer: C

Rationale: CT uses ionizing radiation at relatively high doses.

Compared to plain radiographs, CT is typically:

A. Less expensive
B. More expensive
C. Equally expensive
D. Free of radiation

Correct Answer: B

Rationale: CT costs more than plain films, but less than MRI.

In the acute neuro setting, CT is the imaging modality of choice because it is best for detecting:

A. Chronic demyelination
B. Ligamentous injury
C. Intracranial bleeding
D. White matter tract disruption

Correct Answer: C

Rationale: Head CT is standard for rapid detection of acute hemorrhage.

A patient presents with symptoms of acute stroke 2 hours after onset. The MOST appropriate initial imaging is:

A. MRI with contrast
B. PET scan
C. Head CT
D. Bone scan

Correct Answer: C

Rationale: CT is fast and detects bleeding, which guides acute management.

On a non-contrast CT scan, acute blood appears as:

A. Hypodense (dark)
B. Isodense
C. Hyperdense (bright)
D. Invisible

Correct Answer: C

Rationale: Acute blood has increased radio density, appearing bright.

A CT image showing increased radio density in the left cerebral hemisphere MOST likely indicates:

A. Ischemic infarct
B. Cerebral hematoma
C. Cerebral edema
D. Demyelination

Correct Answer: B

Rationale: Hyperdense blood indicates hemorrhage.

A 3D reformatted CT image is BEST described as:

A. A single axial slice
B. A dynamic real-time scan
C. A volumetric reconstruction that can be rotated
D. A contrast-enhanced scan

Correct Answer: C

Rationale: Volumetric scanning allows 3D rotation of structures.

3D CT reconstructions are particularly useful for:

A. Evaluating metabolic activity
B. Visualizing complex joint anatomy
C. Measuring muscle strength
D. Assessing nerve conduction

Correct Answer: B

Rationale: 3D CT is excellent for complex osseous anatomy (e.g., ankle).

A CT myelogram differs from standard CT because it:

A. Uses magnetic fields
B. Images muscle contraction
C. Uses contrast in the spinal fluid
D. Eliminates radiation exposure

Correct Answer: C

Rationale: Contrast is injected into CSF to outline neural structures.

CT myelography is MOST commonly used preoperatively in patients with:

A. Cervical radiculopathy
B. Thoracic outlet syndrome
C. Symptomatic lumbar stenosis
D. Peripheral neuropathy

Correct Answer: C

Rationale: CT myelograms are often used pre-op for lumbar stenosis.

CT allows assessment of joint or osseous alignment in:

A. The sagittal plane only
B. The axial plane only
C. Any plane
D. Only reconstructed 3D views

Correct Answer: C

Rationale: CT provides multiplanar alignment assessment.

Compared to MRI, CT scans are generally:

A. More time-consuming
B. Less time-consuming
C. Identical in duration
D. Dependent on contrast use

Correct Answer: B

Rationale: CT scans are faster, which is critical in trauma and stroke.

CT scans merge _____ and _____

radiograph and computed imagery

CT scan creates a series of ___ view slices

axial

CT scans are ____ sensitive than radiographs

more

in CT scans the computers ______ reconstruct the image

mathematically

CT scans provide ___ views that are not provided by films

axial

Axial images are displayed as if the patient were _____ and the viewer is at their feet

looking up in a _____ direction

supine; caudo-cephalad

CT scans are best for…

1. Subtle fractures and/or complex fractures

2. Degenerative changes,

such as spinal arthritic changes

3. Serious trauma

4. Spinal stenosis

5. Intervertebral disk

(when combined with diskogram)

6. Loose bodies in a joint

7. Osseous alignment in any plane

pros with CT scan

• Less expensive than MRI

• Less claustrophobic

• Can image soft tissue and osseous structures in one series

• Less time consuming than MRI

cons with CT scan

• Utilizes ionizing radiation

• High radiation exposure

• More expensive than plain film

The correct terminology when referring to magnetic resonance imaging is:

A. MRI image
B. Magnetic image
C. MRI or MR image
D. MR scan image

Correct Answer: C

Rationale: Saying “MRI image” is redundant; correct terms are MRI or MR image.

MRI imaging is performed using:

A. Ionizing radiation
B. X-rays and contrast agents
C. A strong magnetic field and radio waves
D. Sound waves

Correct Answer: C

Rationale: MRI uses non-ionizing radiofrequency waves in a magnetic field.

A key safety advantage of MRI compared to CT is that MRI:

A. Is faster
B. Is less expensive
C. Does not use ionizing radiation
D. Has better bone resolution

Correct Answer: C

Rationale: MRI uses no radiation, unlike CT.

MRI image formation is primarily based on signals emitted from:

A. Calcium ions
B. Oxygen molecules
C. Hydrogen nuclei
D. Sodium channels

Correct Answer: C

Rationale: MRI relies on hydrogen protons responding to radiofrequency stimulation.

Differences in MRI signal intensity between tissues occur because tissues:

A. Contain different minerals
B. Emit different energy signals after stimulation
C. Absorb radiation differently
D. Reflect sound waves differently

Correct Answer: B

Rationale: Energy emitted by hydrogen nuclei varies by tissue type.

MRI images are BEST described as:

A. Single static images
B. Color-coded metabolic maps
C. Grayscale thin slices
D. Three-dimensional ultrasound reconstructions

Correct Answer: C

Rationale: MRI produces thin grayscale slices, similar to CT.

A coronal (frontal) MRI image is viewed as if:

A. Looking from the patient’s feet
B. Looking from the patient’s back
C. Facing the patient
D. Looking from above the patient

Correct Answer: C

Rationale: Coronal images are viewed from the front.

Sagittal MRI images are conventionally viewed:

A. Inferior to superior
B. Anterior to posterior
C. Left to right
D. Right to left only

Correct Answer: C

Rationale: Sagittal images are viewed left → right.

Axial MRI images are viewed in which direction?

A. Cephalo-caudal
B. Caudo-cephalad
C. Medial to lateral
D. Posterior to anterior

Correct Answer: B

Rationale: Axial images are viewed from below upward, like CT.

MRI is considered the BEST imaging modality for evaluating:

A. Cortical bone detail
B. Acute intracranial bleeding
C. Soft tissue structures
D. Joint alignment

Correct Answer: C

Rationale: MRI excels at soft tissue detail.

Which injury is MOST appropriately diagnosed using MRI?

A. Subtle tibial fracture
B. Cortical bone erosion
C. ACL tear
D. Acute skull fracture

Correct Answer: C

Rationale: Ligament tears are classic MRI indications.

MRI is commonly used in athletic injuries because it can detect:

A. Muscle and ligament tears
B. Bone density changes
C. Blood flow velocity
D. Neural conduction

Correct Answer: A

Rationale: MRI detects muscle, ligament, meniscal, labral, and disc pathology.

Contrast injected directly into a joint is MOST commonly used to enhance MRI of the:

A. Knee and ankle
B. Shoulder and hip
C. Spine and pelvis
D. Elbow and wrist

Correct Answer: B

Rationale: Intra-articular contrast is often used for shoulder and hip imaging.

MRI is particularly useful for detecting changes in bone marrow such as:

A. Osteophytes
B. Cortical fractures
C. Bone bruises and avascular necrosis
D. Joint alignment

Correct Answer: C

Rationale: MRI is sensitive to bone marrow pathology.

Which of the following bone-related conditions is BEST evaluated with MRI rather than CT?

A. Cortical bone fracture
B. Bone bruise
C. Complex fracture alignment
D. Osseous anatomy

Correct Answer: B

Rationale: Bone bruises are marrow changes → MRI.

Compared to CT, MRI has LOWER resolution for:

A. Muscle tissue
B. Ligaments
C. Cortical bone
D. Bone marrow

Correct Answer: C

Rationale: CT is superior for cortical bone detail.

According to APTA orthopedic imaging recommendations, MRI is indicated for:

A. Routine screening of asymptomatic patients
B. Suspicious bone lesions and soft tissue masses
C. Initial evaluation of all fractures
D. Acute intracranial hemorrhage

Correct Answer: B

Rationale: MRI is indicated for suspicious lesions, masses, stress fractures.

Two primary limitations of MRI include:

A. Radiation exposure and cost
B. Cost and length of imaging time
C. Poor image quality and noise
D. Limited soft tissue visualization

Correct Answer: B

Rationale: MRI is expensive and time-consuming.

MRI can be challenging for patients primarily because it:

A. Requires breath holding
B. Produces loud noises
C. Requires the patient to remain still
D. Causes thermal injury

Correct Answer: C

Rationale: Motion degrades MRI images, especially in painful patients.

MRI is contraindicated in patients with:

A. Titanium implants
B. Ferromagnetic surgical clips
C. Plastic prosthetics
D. Non-metallic sutures

Correct Answer: B

Rationale: Ferromagnetic materials interact dangerously with the magnetic field.

Orthopedic hardware may limit MRI usefulness because it:

A. Blocks radio waves
B. Causes excessive heating
C. Distorts the image
D. Increases scan time

Correct Answer: C

Rationale: Metal can create artifact and distortion.

Why are pacemakers a contraindication for MRI?

A. They block image acquisition
B. They interfere with hydrogen nuclei
C. They may malfunction in magnetic fields
D. They increase radiation exposure

Correct Answer: C

Rationale: Strong magnetic fields can disrupt pacemaker function.

A major limitation shared by MRI and other imaging modalities is that:

A. They cannot visualize anatomy
B. Findings may not correlate with symptoms
C. They are operator dependent
D. They lack reproducibility

correct Answer: B

Rationale: Imaging findings do not always match clinical presentation.

Compared to CT in acute trauma, MRI is LESS commonly used because it is:

A. Less accurate
B. More expensive and slower
C. Unable to image the brain
D. Unsafe for soft tissue

Correct Answer: B

Rationale: MRI is slow and costly, limiting acute use.

The two primary MRI sequences emphasized in this course are:

A. STIR and proton density
B. Gradient echo and fMRI
C. T1- and T2-weighted images
D. Dynamic and angiographic sequences

Correct Answer: C

Rationale: The course focuses on T1 and T2 weighted imaging.

T1 and T2 phenomena differ primarily in their:

A. Use of contrast agents
B. Relationship to proton realignment with the magnetic field
C. Sensitivity to metal artifact
D. Ability to image cortical bone

Correct Answer: B

Rationale: They represent different proton relaxation processes.

T1- and T2-weighted phenomena occur:

A. Independently
B. Sequentially
C. Simultaneously
D. Only with contrast

Correct Answer: C

Rationale: T1 and T2 occur at the same time, but represent different processes.

T1-weighted imaging is characterized by:

A. Long TR and long TE
B. Short TR and short TE
C. Long TR and short TE
D. Short TR and long TE

Correct Answer: B

Rationale: Short repetition time (TR) and short echo time (TE) define T1.

On a T1-weighted image, tissues with high water content appear:

A. Bright
B. Intermediate
C. Dark
D. Variable

Correct Answer: C

Rationale: Water has low signal intensity on T1 → dark.

T2-weighted images are characterized by:

A. Short TR and TE
B. Short TR and long TE
C. Long TR and long TE
D. Long TR and short TE

Correct Answer: C

Rationale: Long TR and TE define T2-weighted imaging.

On a T2-weighted image, tissues with high water content appear:

A. Dark
B. Bright
C. Isodense
D. Absent

Correct Answer: B

Rationale: Water has high signal intensity on T2 → bright.

The phrase “H₂O is bright on T2” is used to remember that T2-weighted images are best for detecting:

A. Fat
B. Cortical bone
C. Swelling and edema
D. Ligaments

Correct Answer: C

Rationale: T2 highlights fluid, swelling, and inflammation.

Compared to T2, T1-weighted images generally provide better:

A. Detection of swelling
B. Visualization of cortical bone
C. Anatomic detail
D. Visualization of effusion

Correct Answer: C

Rationale: T1 is superior for anatomic detail.

On a T1-weighted MRI, fat and bone marrow typically appear:

A. Dark
B. Bright
C. Variable
D. Invisible

Correct Answer: B

Rationale: Fat and marrow have high signal intensity on T1.

On a T2-weighted image, muscle typically appears:

A. Bright
B. Slightly darker than fluid
C. Hyperintense compared to fat
D. Identical to bone marrow

Correct Answer: B

Rationale: Muscle is darker than fluid on T2.

MRI image slices include personal information such as name and date, as well as technical information indicating:

A. Radiation dose
B. Contrast concentration
C. Imaging sequence
D. Slice thickness only

Correct Answer: C

Rationale: Technical info includes sequence type (T1, T2, etc.).

In MRI terminology, a protocol refers to:

A. A single imaging slice
B. A standardized national sequence
C. A combination of sequences for a body part
D. Use of contrast material

Correct Answer: C

Rationale: A protocol is a set of sequences tailored to the body part/pathology.

MRI protocols are best described as:

A. Standardized across all facilities
B. Identical for every joint
C. Dependent on body part and suspected pathology
D. Fixed for all orthopedic conditions

Correct Answer: C

Rationale: There are no universal MRI protocols.

Bone marrow edema would appear MOST clearly on which image type?

A. T1-weighted
B. T2-weighted
C. CT scan
D. Plain radiograph

Correct Answer: B

Rationale: Edema = water → bright on T2.

In a sagittal MRI of the knee, bone marrow appears brighter on which image?

A. T2 only
B. T1 only
C. Both equally
D. Neither

Correct Answer: B

Rationale: Bone marrow is bright on T1.

Quadriceps tendon and patellar ligament typically appear:

A. Bright on both T1 and T2
B. Dark on both T1 and T2
C. Bright on T1 and dark on T2
D. Dark on T1 and bright on T2

Correct Answer: B

Rationale: Tendons and ligaments have low signal intensity.

Synovial fluid on a T2-weighted MRI will appear:

A. Dark
B. Bright
C. Intermediate
D. Absent

Correct Answer: B

Rationale: Fluid is hyperintense on T2.

A bone bruise following knee trauma would appear as high signal intensity on:

A. T1-weighted imaging
B. T2-weighted imaging
C. CT scan
D. Plain radiograph

Correct Answer: B

Rationale: Bone bruise = marrow edema → bright on T2.

When comparing T1 and T2 images of the ankle and foot, differences in signal intensity are due to:

A. Slice thickness
B. Radiation exposure
C. Water content of tissues
D. Patient positioning

Correct Answer: C

Rationale: Signal differences reflect tissue water content.

Which MRI sequence is MOST similar to T1-weighted imaging and best for anatomic detail?

A. STIR
B. Proton density
C. Gradient echo
D. Functional MRI

Correct Answer: B

Rationale: Proton density resembles T1 and highlights anatomy.

Which MRI sequence is MOST sensitive for detecting fractures?

A. T1-weighted
B. Proton density
C. STIR
D. Gradient echo

Correct Answer: C

Rationale: STIR suppresses fat and highlights edema → fractures.

Functional MRI (fMRI) is primarily used to assess:

A. Bone marrow changes
B. Cortical bone anatomy
C. Brain activity
D. Joint alignment

Correct Answer: C

Rationale: fMRI evaluates functional brain activity.

A summary comparison of CT, T1, and T2 imaging would show that swelling or effusion appears MOST bright on:

A. CT
B. T1-weighted MRI
C. T2-weighted MRI
D. Plain radiograph

Correct Answer: C

Rationale: Fluid = bright on T2.

MRI use ___ radiation

NO

____ is based on energy emitted from hydrogen nuclei after their stimulation by radiofrequency

MRI

MRI is best for

Partial or complete muscle or ligament tears

• Disc herniations

• Meniscus or labral tears (need Gadolinium contrast

• injected into joint to enhance image—shoulder/hip)

• Changes in bone marrow (bone bruises, AVN, bone tumors, etc)

• Staging neoplasm in bone and/or soft tissue

___ do not give as high res of cortical bone as ___ but can still be used for bony pathologies

MRI//CT

disadvantages of an MRI

• High cost

• Claustrophobia of the patient

• Length of time to complete (do not get images right away)

• Pt needs to sit still to get adequate image (difficult if they are in pain)

• Cannot do with ferrous metal in the body

• Findings do not always correlate to symptoms

contraindications of an MRI

• Any metal implants (aneurysm clips, shrapnel, industrial metal working, etc.)

• Ortho hardware is not ferromagnetic BUT will distort image

• Pacemakers may malfunction

when would someone get an MRI (list)

• + localized or regional symptoms suspicious for bone lesion.

• Radiographs negative or findings do not explain symptoms.

• Bone lesion on radiographs. Next study in most clinical scenarios.

• “Incidental” bone finding on CT. Not clearly benign. No prior radiographs.

• Soft‐tissue mass, next study following radiographs:

1. nondiagnostic, or

2. with prominent calcification.

• Potential stress fracture (fatigue/insufficiency).