Abdominal #11

Clinical Information

– 53-year-old male
– Left adrenal nodule was incidentally found on a CT scan
– MRI was performed for better characterization

What are the Imaging Findings

– Left adrenal nodule with loss of signal intensity on out-of-phase image

What is the most likely diagnosis?

Adrenal adenoma:
– The most important characteristic feature is the presence of intracellular lipid.
– Chemical shift imaging is the most reliable technique for diagnosing adrenal adenoma: most of them demonstrate a loss of signal intensity on out-of-phase MR images.

Musculoskeletal #28

Prune Belly Syndrome

What are the features?

Features

There are three cardinal features:
– Bilateral undescended testicles
– Dilated urinary tract
– Deficient abdominal wall musculature.

These manifestations place patients with prune belly syndrome at risk for testicular malignancy, infertility, urinary tract infections, and renal failure.

The Prune Belly syndrome is also known as:
– Eagle-Barrett syndrome
– Abdominal musculation syndrome

What is the incidence of PBS?

– PBS has a contemporary incidence of 3.6–3.8 per 100,000 live male births
– It is a predominantly male diagnosis as <5% of those diagnosed are female

What are the major manifestations of PBS, giving rise to its alternative name of the triad syndrome?

– A deficiency of abdominal musculature leading to a wrinkled “prune- like” appearance of the abdominal wall.
– Bilateral intra-abdominal testes.
– Urinary tract dysmorphism. The urinary tract anomalies are characterized by differing degrees of renal dysplasia, hydronephrosis, dilated tortuous ureters, an enlarged bladder and a dilated prostatic urethra.

What percentage of patients with PBS are female? What are the major manifestations of PBS in a female?

– Only 5% of PBS diagnoses are female.
– Females exhibit only deficiency of abdominal wall musculature and the anomalous urinary tract without any gonadal abnormality.

Other abnormalities

– 75% of children with PBS have non-urinary tract abnormalities
– These abnormalities include respiratory (58%, e.g. pulmonary hypoplasia), cardiac (25%, e.g. patent ductus arteriosus, atrial septal defect, ventricular septal defect, tetralogy of Fallot), gastrointestinal (63%, e.g. constipation, incomplete rotation of the midgut) and musculoskeletal anomalies (65%, e.g. talipes equinovarus, scoliosis, hip dysplasia)

What is the incidence of prematurity

The incidence of prematurity in the PBS population is nearly 50%.

What is the perinatal mortality of those born with PBS?

– Perinatal mortality ranges between 10 and 29% in contemporary studies.
– Perinatal mortality is directly connected to the level of prematurity and severity of pulmonary hypoplasia.

What is the most common urinary tract abnormality?

Hydroureteronephrosis is almost always present and most commonly bilateral.
– The distal ureter is usually where massive dilation occurs; however the presentation is variable.
– Hydroureteronephrosis is almost never due to obstruction within the ureter, rather, lower urinary tract obstruction (posterior urethral valves), vesicoureteral reflux, and a histologic deficiency of smooth muscle and preponderance of fibrous tissue in the ureters leading to ineffective peristalsis

Musculoskeletal #27

53-year-old female:

– Chronic sensory polyneuropathy (autoimmune). Long-term corticosteroid therapy.
Forefoot pain for three weeks (acute onset without trauma).
– Physical examination: no haematoma , mild swelling.
X-ray performed on day 2 after initial pain.
MRI performed on day 25 after initial pain.

What are the findings?

X-Ray: No obvious fracture.

MRI:
– Bone marrow heterogeneous oedema within the third metatarsal diaphysis (hypointense on T1W image, hyperintense on Proton Density (PD) FatSat image).
Linear low signal intensity fracture identified in all sequences.
Periosteal reaction due to callus formation. Periosteal thickening and enhancement (contrast administration is not necessary for diagnosis).
– Surrounding soft-tissue oedema (adjacent fat and interosseous muscles).

Metatarsal stress fracture (“march fracture”)

– Stress fractures are caused by overuse and repetitive activity.
– Everyday activities may result in a stress fracture if there is any disease or therapy that weakens the bone such as osteoporosis or long-term use of steroids (bone insufficiency: long-term treatment with steroids in this case).
– Classically affects the 2nd or 3rd metatarsal of the foot “march fracture”: named after its prevalence in soldiers who often undertake repeated and prolonged periods of walking as part of their training or work.
– Bone changes are usually not evident on X-rays before 10 to 21 days following the injury. May not be visible for several weeks later, until callus bone formation (the sensitivity range, for detecting stress fractures on initial examinations, is 15-35%; it increases to 30-70% at follow-up studies due to bone reaction).

MRI findings:
– The fluid-sensitive sequences (T2-weighted images with chemically selective fat suppression or STIR sequences) are very useful for the detection of the earliest changes of stress reaction, such as periosteal reaction, muscle, or bone marrow oedema.
– T1-weighted sequences depict the anatomy and more advanced stress-related findings.

Grading based on MRI (Arendt and Griffiths)🙂
1: Mild – moderate periosteal oedema on STIR, no marrow changes.
2: Moderate – severe periosteal oedema on STIR + marrow changes on T2-weighted.
3: Grade 2+ marrow changes on T1-weighted.
4: Fracture line visible.

Head and Neck #12

24-year-old male:
– Feels a lump in the upper lateral corner of right eye.
– MRI was made.

What do you see?

Preseptal lesion right supero-lateral corner, lateral to lacrimal gland.
T2 and T1 hyperintense, low signal after fat suppression.
No enhancement (right upper picture).
Slight remodeling of bone.
No invasive growth no post-septal component.

What is the most likely diagnosis?

Diagnosis: dermoid cyst, also fits with age and location of lesion.

Head and neck #8

Where is the lesion?

Left carotid sheath posterior to the carotid bulb, internal, and external carotid arteries.

How does it look like?

Large oval avidly enhancing lesion displacing the carotid bifurcation anteriorly.

What is the differential diagnosis?

Carotid bulb paraganglioma: avidly enhancing lesion with characteristic splaying of the internal and external carotid arteries (lyre sign).
Glomus vagale: paragangliomas but of the vagus nerve, located posterior to the carotid arteries displacing them anteriorly.
Vagal schwannoma: those that arises within the carotid sheath posteriorly but usually shows moderate enhancement compared with the avid enhancement of the paragangliomas.

What is the most likely diagnosis

Glomus vagale

Musculoskeletal #26

Describe the abnormality

Bilateral sacroiliac joint space narrowing, subchondral erosions, subchondral sclerosis, and subchondral fatty marrow infiltration.

What is the differential diagnosis?

Bilateral symmetrical:
Ankylosing spondylitis
Inflammatory bowel disease. 

Bilateral asymmetrical:
Psoriasis
Reactive arthritis (Reiter syndrome) 

What is the most likely diagnosis?

Ankylosing spondylitis

What are the markers of active inflammation?

Erosions with high signal intensity on STIR or T2- weighted images, subchondral edema, and enhancement within or adjacent to the sacroiliac joint.

What are the markers of chronic disease?

Low signal intensity on T1- and T2- weighted images, subchondral sclerosis, narrowing of the joint spaces, bone bridging, and ankylosis.