Ultrasound of the spine for dysraphism

To look for occult spinal dysraphism

Clinically features suggestive for occult spinal dysraphism:
- Sacral dimple
- Tuft of hair
- Vascular patch / haemangioma
- Overlying skin appendage / skin tags
- Other anomalies which maybe associated with tethered cord eg imperforate anus, lower limb neurology

When to do / When not to do:
- Avoid performing if patient <2/52 old (often not enough CSF). Can do if high clinical probability.
- 2/52 to 4-6/12
- Not ideal if >6/12 old as spinous processes starts to ossify, obscuring the view

Preparation:
Patient relaxed eg just finished feeding, sleeping
Position: Prone or lying on side
High resolution linear probe

What to look for / document:
Sagittal view: (through the cartilaginous spinous processes)

1. Level of conus: L2/L3 disk or above, may be lower if pre-term
- If 'low lying' in pre-term, followup scan at 40wk after corrected age.
- Low lying cord may imply cord tethering
- Count the vertebral levels (reference point):
-- from below: sacrum or 1st coccygeal segment
-- from above: last rib
- may be supplemented with lateral spine radiograph to aid in counting in difficult cases, marker can be placed at the level of conus termination

2. Morphology of conus: Normally tapers down.

3. Normal pulsating motion of the spinal cord
- Absence in tethering

4. Dependent position of spinal cord (difficult to ascertain if not enough CSF as in the case of performing in patient below 2/52 old)
- Normal: Lie on anterior 1/3 or halfway in the canal.

5. Filum terminale thickness
- Normal </=2mm

Transverse view:

6. Spinal vertebral dysraphism (posterior elements)

Developmental Dysplastic Hip

DDH:
- Acetabular dysplasia AND/OR ligamentous laxity, resulting in recurrent hip subluxation / dislocation
- Left hip affected more than Right hip

Risk factors for DDH:
1. Breech presentation
2. Female (?estrogen contributing to ligamentous laxity?)
3. Firstborn
4. Family Hx
5. Oligohydramnios , Multiple gestation - abnormal posture due to crowding in-utero

Clinical features:
1. Asymmetric thigh skin folds
2. Shortened leg
3. Decreased hip ROM when Flexed and ABducted
4. Positive Ortolani and Barlow signs

Ultrasound used to assess the hips - the cartilaginous components can be seen. ie not ossified yet

Contraindications to US Hips:
1. Generally avoid if patient <3-4/52 old, as the ligaments are normally lax. Usually done at 6/52 and after.
2. Not suitable after 6mo. Femoral head ossifies, starts around 2-3mo.
Radiographs are a better modality of choice when the bone ossifies (>12mo) - AP radiographs, not frog leg view.

Ultrasound:
Done when patient is relaxed. eg. whilst feeding
Use high-resolution linear probe.

1. Coronal view
Hip slightly flexed. (~15-20degrees)
These structures should be seen, in addition to the femoral head, greater trochanter, acetabular roof.
a. Ossified ilium is horizontally orientated
b. Triradiate cartilage
c. Labrum

Look for:
1. Morphology of the hip joint
2. Coverage of femoral head using the straight ilium line (Position)
3. Alpha angle

2. Transverse view
Hip flexed. (90 degrees)
Look for: Hip joint stability
Visualisation of the hip joint whilst performing
- Barlow maneuvre
- If dislocatin/subluxation present, perform Ortolani maneuvre

Graf system (US hip for DDH introduced by Graf - Orthopaedic Surgeon)
- To grade severity of DDH and appropriate management

Graf system		Acetabular rim	Labrum	Ossified ilium line	Alpha angle
Type I	-	Normal angular	Normal	Crosses >50% of femoral head	>60	Normal
Type IIa	Age: <3mo	Rounded	Normal	Crosses <50% of femoral head, but not displaced	50-59	Physiologic immaturity. Repeat scan in 6-8/52
Type IIb	Age: >3mo	Same finding as IIa				Refer orthopaedic
Type IIc		Same finding as IIa	Everted / horizontal position	Same finding as IIa	43-49
Type IIIa	Normal acetabular roof cartilage	Flattened	-	Displaced (<50%)	<43	Refer orthopaedic
Type IIIb	Abnormalechogenic acetabular roof cartilage	Same finding as IIIa
Type IV	-	Flattened		Complete displacement	<43	Urgent orthopaedic referral

Radiographs:
1. Asymmetric hip joints
2. Asymmetric femoral epiphysis ossification: As a complication of DDH where there is delayed ossification
3. Femoral head crossing the Perkin's line laterally
4. Acetabular angle >30degree
5. Disruption of Shenton's line

Hilgenreiner's line:
Transverse line touching the triradiate cartilage superiorly and bilaterally on AP pelvis view

Perkin's line:
Line perpendicular to Hilgenreiner's line, touching lateral margin of the ossified acetabular roof on AP pelvis view.

Acetabular angle:
Angle between Hilgenreiner's line and the acetabular roof.
Normal: <30degree

Shenton's line:
Smooth curve lining the inferior margin of the superior pubic ramus and the medial margin of the proximal femur.

Putti's triad:
1. Femoral head displace superolaterally
2. Small femoral epiphysis
3. Acetabular angle > 35degrees

Cotswold modification of Ann-Arbor Classification for Hodgkin lymphoma

For staging and prognosis of Hodgkin lymphoma.

Stage I	1 or 2 contiguous regions of lymph nodes on same side of diaphragm
Stage II	> 2 contiguous regions of lymph nodes on same side of diaphragm
Stage III	Both sides of diaphragm
Stage IV	Organ involvement*
X	Bulky disease >10cm
E	Extranodal involvement – used in conjunction with stage I-III
A/B	A: Absence of symptoms / B: Presence of constitutional symptoms

*Thymus and Spleen are lymphoid organ, thus included in the ‘lymph node’ involvement. They are not considered as ‘organ’ in this context.

Sarcoidosis

Sarcoidosis
Idiopathic. Granulomatous disease (non-caseating).
Systemic disease involving the lymph nodes, lungs, liver, heart etc.
Lung is the most commonly involved organ.

Clinical features:
- 3rd or 4th decades
- More in African american
- 70% have increased serum ACE - An indicator of the granuloma burden on the body

Nuclear Medicine:
- Gallium (Ga 67 scintigraphy) avid during active phase. No uptake when in remission.
Degree of uptake corresponds to degree of severity
Confirms diagnosis of sarcoidosis
Differentiate active alveolitis from inactive fibrosis
Signs:

1. Lambda sign: Hilar and Right paratracheal nodal uptake
2. Diffuse pulmonary uptake
3. Panda sign: Lacrimal and salivary glands inflammation

- PET scan: FDG avid during active phase. SUV can be >2.5

Acute Sarcoidosis

aka Lӧfgren syndrome
Clinical features:
- Fever, malaise, arthralgia +/- parotitis / uveitis
- Erythema nodosum
- Serum ACE level often increased
- Erythema nodosum
Has bilateral hilar lymphadenopathy, but absence of lung changes

Lungs:

Garland’s triad (1-2-3 sign)
Lambda sign on Gallium scan

1. Bilateral hilar lymphadenopathy
2. Right paratracheal lymphadenopathy

CXR:

-          Reticulonodular opacities, bilateral upper lobe dominant

-          Symmetric bilateral hilar, paratracheal, aortopulmonary window lymphadenopathy

HRCT:

-          Lymphadenopathy
-     1-5mm nodules in centrilobular and subpleural distribution
-     Upper lobe and peribronchovascular distribution
-     Irregular interlobular septal thickening
-     Architectural distortion

-          Advanced: Interstitial fibrosis- Peripheral honeycombing, Bullae
-     Some cases (rare): Alveolar sarcoidosis = Peripheral consolidation + Mediastinal and Bilat.hilar lymphadenopathy

Radiographic staging:
-     Stage 0: Normal CXR

-          Stage I: disease limited to mediastinal nodes

-          Stage II: involvement of lung and lymph nodes

-          Stage III: involvement of lung only

-          Stage IV: lung fibrosis

DDx:
- When advanced, can mimic progressive massive fibrosis (PMF)

Cardiac

Result in:
- Arrhythmia
- Ventricular aneurysms
- Sudden death

Head & Neck:

Involvement of glandular tissues, muscles, nerves.
1. Optic nerve and EOM hypertrophy and enhancement - uveitis
2. Parotid glands and lacrimal glands exhibits heterogeneous bilateral symmetrical enlargement - chronic dacroadenitis, parotitis

Gallium scan: "Panda sign" where there is increased uptake of the parotid and lacrimal glands (Looks like the whole panda sitting on the person's neck / replacing the head)

Neurological system:

Neurosarcoidosis, 5% of sarcoidosis patient
Usually lungs would have been involved already.
Granulomatous infiltration of the perineural tissue
Involvement of nerves, optic chiasm, hypothalamus, infundibulum, IAM
Presenting with cranial nerve deficits

Imaging:
Exhibit contrast smooth / nodular enhancements along the involved nerves, thickened leptomeninges, pachymeninges
Also enhancement in the perivascular space, ependyma
5% have solitary extra-axial mass

Complication: Hydrocephalus

Gastrointestinal:

Spleen:
Splenomegaly
Present as splenic granulomas, +/- calcification
If present = advanced stage of Sarcoidosis.
Spontaneous splenic rupture (rare)

Lymph nodes:
Mesenteric nodes

Musculoskeletal:

Affect small bones of hands and feet
Reticulated trabecular pattern (lace-like)
Cyst-like lesions
Destruction of terminal phalanges
Diffuse sclerosis of the vertebral bodies
Osteolysis in skull

Bonescan lesions

3 +/- 1 phase Bone scan
1st phase: Arterial blood flow; immediately after injection
2nd phase: Blood pool (tissue phase) 10min after injection
3rd phase: Delayed phase (Skeletal phase) 2-5hr after injection
4th phase: 24hr delayed phase if renal insufficiency and as a result suboptimal image on 3rd phase

Standard whole body bone scan: Acquire at delayed phase (skeletal phase)
Mechanism: Radiotracer adsorbed on hydroxyapatite matrix of the bone, where the mineral phase is active.

Superscan:
Increased radiotracer uptake of bone in relative to the soft tissue background and (almost) absent renal activity.
Causes:

1. Widespread metastasis in: Breast / Lung / Prostate CA, +/- Lymphoma +/- Bladder CA
2. Metabolic bone disease: Renal osteodystrophy, Osteomalacia, Hyperparathyroidism
3. Myelofibrosis, Systemic mastocytosis

Hot lesions:

1. Fibrous dysplasia
2. Paget's disease
3. Brown tumors
4. ABC (because it is very vascular)
5. Osteoid osteoma
6. Chondroblastoma
7. Metastasis (Osteoblastic activities ie Sclerotic eg Prostate CA mets)
8. Joint diseases
9. Dental infection
10. Acute fracture (after 24 - 48hr)

3 phase positive lesions: (lesions that causes bone remodelling)

1. Osteomyelitis
2. Healing fracture
3. Orthopaedic implant
4. Neuropathic osteoarthropathy

Normal scan: (no increased or decreased uptake)

1. Acute fracture (acute phase)
2. Bone cyst, bone island, exostoses
3. Multiple myeloma ** there for this condition is monitored by skeletal survey radiograph**
4. Osteoporosis

Cold lesions:

1. Radiotherapy
2. Avascular lesion
3. Multiple myeloma 
4. Haemangioma
5. Advanced carcinoma

Varying lesions

Mixed lytic/sclerotic metastasis (Breast, Lung etc) may show hot or cold (with hot margins).