This is a 48-year-old man who fell nine months ago and now has swelling and pain in the right index finger.
- What do the paired arrows label in image 1?
- What does the single arrow label in image 1?
- What does the single vertical arrow label in image 2?
- What do the sets of three paired arrows label in image 2?
- With image three, what do you think is the patient’s story?
- The paired arrows point to a torn ulnar collateral ligament in the first image.
- The single long arrow points to periosteal perpendicular reaction (first image).
- The single vertical arrow (second image) points to an inflamed irregular destructive erosion.
- The multiple short-axis arrows on T1 coronal imaging (second image, three paired arrows) point to extensive periosteal reaction.
- The most plausible explanation for what has happened to this finger is a traumatic injury leading to instability, cartilage injury and collateral ligament injury resulting in chronic indolent infection of the joint space. To back this up, see short-axis axial T2 in which arrows point to a large proteinaceous palmar effusion (short-axis T2 arrows, third image).
- For more case review, head to MRI Online.
This 69-year-old male presents with visual deficit. The finding on CT is a left occipital stroke. In what vascular territory is it distributed? Would the MRI be positive? More specifically, would a FLAIR MRI be positive? What about a diffusion MRI?
The location of the stroke is the left posterior cerebral artery territory. FLAIR MRI would never be normal when CT is positive. It is inordinately more sensitive and positive in the first 24 hours after a stroke. The diffusion MRI is positive even earlier than the FLAIR, as early as three hours.
ProScan Pearl: To find blood in a stroke on MRI, consider blood-sensitive sequences like BSI (Hitachi), SWI (GE), SWAN (Siemens) or Venous BOLD (Philips). Blood in a small stroke may “hide” or obscure diffusion imaging findings – pseudonormality. For more neuro case review, head to MRI Online.
This 57-year-old male presents with a large mass. What is it? But, more importantly, on these axial water-weighted MRI images, what is the potentially life-threatening finding?
The high signal mass is a gastrocnemius semimembranous bursal cyst (one of the many types of Baker’s cysts). The life-threatening finding is the absence of flow phenomena in the popliteal vein. This thrombosis (arrows) can eventually result in a pulmonary embolism. When a Baker’s cyst clinically simulates a popliteal thrombophlebitis, this is called pseudothrombophlebitis. But when it actually coexists with the thrombophlebitis due to compression (as in this case) it is called pseudo-pseudothrombophlebitis.
After you try to say pseudo-pseudothrombophlebitis five times fast, head to MRI Online for more knee case review.
This 10-year-old presents with right knee pain and swelling. There is no known trauma. What’s the most likely diagnosis? What is indicated by the arrows in the back of the knee? Is it concerning?
The diagnosis is Sinding-Larsen-Johansson syndrome or inferior patellar “apophysitis” (yellow arrow). The green arrows indicate lymph nodes, and they are innocuous (since they contain fat in the coronal). It is common to see lymph nodes behind the femur, particularly in children. Of course they are more numerous or larger in patients with inflammatory processes of the knee such as JIA (juvenile idiopathic arthritis).
For more knee case review, visit MRI Online.
This 59-year-old presents with heel pain. Diagnosis is obvious on water-weighted sagittal MRI, but how do you repair this?
It’s an obvious plantar fasciitis with a tear. As for how to repair it, that’s a trick question. You put the patient in a boot and manage their pain. The surgical treatment for plantar fasciitis is cutting the fascia, so-called plantar fascial release. But this patient did it themselves “without the surgeon.” “Patient, heal thyself.” For more case review, check out MRI Online.
This 55-year-old female presents with a droopy eye, which isn’t something to be taken lightly. In this particular case, the droopy eye is symptomatic of a syndrome with a name you might remember.
Remember Horner’s syndrome, i.e. ptosis meiosis anhydrosis? Here is the classic cause, carotid dissection, with a meniscal curvilinear appearance of the vessel wall. If you hear this history, make a beeline for the carotid canal and you will have a great diagnosis. I have even seen neck vascular dissection from a sneeze.
For more neuro case review, check out MRI Online.
You are shown two MRI images. One is a standard orthogonal coronal with a line through it. This shows the angle of acquisition to evaluate the alpha angle. The second image is the axial oblique with the lines used for alpha angle measurement. Questions:
- What is a normal alpha angle?
- What does an abnormal alpha angle suggest?
- Is an abnormal alpha angle pathognomonic of a symptomatic disease process?
- Normal alpha angle is 55 to 60 degrees or less.
- Increased alpha angles suggest cam impingement syndrome or impingement syndrome type 1.
- The yellow line in the second image is placed from the center of the femoral head to the junction of the medial transition of the upper femoral head to the bump. The green line bisects the center of the femoral head, neck, and trochanteric region as demonstrated on the axial oblique image.
- Athletic, large men often have abnormal alpha angles in the absence of symptoms. Therefore, the alpha angle is not pathognomonic of symptomatic cam impingement, only suggestive.
- For more orthopaedic case review, head to MRI Online.
This 87-year-old man presents with two cancers. Note they are unrelated and not the result of one cancer spreading to another organ. What are the two cancers? Advanced questions: Can you posit the T stage of cancer #1 from limited imaging? How valuable is diffusion imaging in the prostate as an example?
Answer: Prostate and rectal cancer. You can posit the T stage of the prostate lesion on the left (arrow) as T3b as there is seminal vesicle invasion. The diffusion image is especially valuable for mass-like lesions over 3 millimeters in size in the prostate peripheral zone. Many “benign’ or nonaggressive central zone masses in the prostate will have mild diffusion restriction. For more prostate staging resources, visit MRI Online.