DPM Diagnostic Imaging Interpretation 3

Question 1

On CT imaging, which finding best distinguishes a fibrous from an osseous tarsal coalition?

Accepted Answer

Non-ossified bridging tissue with irregularity at the joint margins

Answer

Fibrous coalitions show irregular, non-corticated joint margins without complete bony fusion, whereas osseous coalitions demonstrate trabecular continuity.

Question 2

Which nuclear medicine study is most sensitive for detecting early diabetic foot osteomyelitis before radiographic changes appear?

Accepted Answer

FDG-PET/CT

Answer

FDG-PET/CT offers superior spatial resolution and sensitivity for early osteomyelitis compared to conventional nuclear studies, though labeled WBC scan is also highly specific.

Question 3

The 'lover's heel' or 'policeman's heel' radiographic sign describes a large inferior calcaneal spur; this spur arises from which structure?

Accepted Answer

Origin of the intrinsic foot muscles, not the plantar fascia itself

Answer

The inferior calcaneal spur arises from the origin of the flexor digitorum brevis and intrinsic muscles at the medial calcaneal tubercle, not directly from plantar fascia.

Question 4

On MRI, Morton's neuroma (interdigital neuroma) appears most characteristically as:

Accepted Answer

Low T1, low T2 signal mass in the intermetatarsal space with dumbbell shape

Answer

Morton's neuroma shows low to intermediate T1 and low T2 signal due to fibrous tissue, with a characteristic dumbbell or teardrop shape between metatarsal heads.

Question 5

On a standard AP ankle radiograph, talar tilt measurement evaluates the integrity of which ligamentous complex?

Accepted Answer

Lateral collateral ligament complex (ATFL and CFL)

Answer

Talar tilt under varus stress assesses the lateral collateral ligaments, particularly the ATFL and CFL; greater than 10° tilt indicates instability.

(DPM) Doctor of Podiatric Medicine Practice Test

(DPM) Doctor of Podiatric Medicine Practice Test

DPM Diagnostic Imaging Interpretation 3