Medial Epicondyle Fracture of the Humerus

AP views of both elbows of an 18-year-old boy who sustained an injury to the right elbow.  There is an avulsion fracture (arrow) of the medial epicondyle of the right humerus. Radiograph of the left side demonstrates different areas of distal humeral structures from medial to lateral: medial epicondyle, trochlea, capitellum and lateral epicondyle. 

Facts:

• Common pediatric elbow fracture (3rd common, after supracondylar and lateral condylar fractures)
• Valgus strain at elbow joint
• Two main types: simple avulsion (1/2) and fracture-dislocation (occurring with lateral elbow dislocation; 1/2)
• Indications for surgery include 1) displaced fragment trapped in joint preventing reduction, 2) ulnar neuropathy, 3) valgus instability, 4) open fracture

Imaging:

• Look for displaced fragment trapped in the joint and degree of displacement because they might indicate surgery
• In patients less than 8 years, trochlea may be non-ossified and this may be confused with fracture of medial condyle, which is rarer and could be more complicated
• Another imaging Ddx is osteochondrosis

References:

Wilson JN. The treatment of fractures of the medial epicondyle of the humerus. J Bone J Surg 1960;42:778.

Gottschalk HP, Eisner E, Hosalkar HS. Medial epicondyle fracture sin the pediatric population. J Am Acad Orthop Surgeons 2012; 20:223.

Wheeless' Textbook of Orthopedics link

Mosaic Pattern of Lung Attenuation

Axial CT images of the chest in lung windows (inspiratory images) shows multilobular areas of variable lung attenuation (mosaic pattern) with dark areas showing diminished size/numbers of pulmonary vessels indicating that these dark areas are abnormal. 

Facts:

• Lobular or multilobular distribution of variable lung attenuation
• Three possible groups of etiologies: small-airway, vascular and infiltrative disease 
• Additional findings are helpful to distinguish the three causes

Making Decisions

1. Dark or white areas are abnormal? Looking at size and number of vessels in both regions. If they are similar, the "white" is abnormal (meaning it is ground glass abnormality). If the size/number of vessels in dark areas are decreased, this is either small-airway or vascular pathology
2. If the "white" is abnormal, look for differentials of ground glass opacity (GGO)
3. If the "dark" is abnormal, look at expiratory phase scanning. If air trapping is present, this is small-airway disease. If there is no air trapping, this is likely vascular cause
4. If expiratory scanning was not available, look at clinical features.  Dyspnea, cough, wheezing and response to bronchodilators are common in patients with small-airway disease and infrequent in vascular lung disease

Our case: We did not perform expiratory scan in this patient but given clinical scenario, the dark areas likely represent mosaic pattern from known chronic pulmonary embolism with pulmonary hypertension. 

Reference:

Stern EJ, et al. CT mosaic pattern of lung attenuation: distinguishing different causes. AJR 1995;165:813.

Pseudothickening of Colonic Wall

Axial and coronal-reformatted CT images of a 58-year-old woman show apparent circumferential wall thickening of the sigmoid colon (arrows) with a smooth transition into the more proximal colon. No pericolonic fat stranding is seen. Colonoscopy was performed but showed no colonic pathology.  Subsequent follow-up CT was also normal.  

Facts:

• When distended, normal colonic wall should be less than 3 mm or even imperceptible
• Fecal contents, fluid or colonic redundancy make true wall measurement difficult or impossible

Pseudothickening of Colonic Wall

• Could be mistaken for true pathology such as annular neoplasm or inflammatory stenosis
• Pseudothickening should be mild. Its margin should gradually return to full distention
• Normal pericolonic fat

References:

Mang T et al. Pitfalls in multi-detector row CT colonography: a systematic approach.. Radiographics 2007;27:431.

Macari M, Balthazar EJ. CT of bowel wall thickening significance and pitfalls of interpretation. AJR 2001;176:1105.

Olfactory Groove Meningioma

Axial T2W MR image shows a lobulated extraaxial mass in the midline anterior cranial fossa. The mass is T2 isointense with a central area of higher T2 signal intensity. Mild brain edema of the inferior frontal lobes are noted. 

Sagittal post-contrast T1W MR image shows uniform enhancement of the mass.  It better demonstrates the location of the mass that is anterior to the tuberculum sellae.

Facts: Olfactory Groove Meningioma

• Usually asymptomatic until large. 
• When symptomatic, they can produce Foster Kennedy syndrome (anosmia, ipsilateral optic atrophy, contralateral papilledema), metal status change, urinary incontinence
• Histological variables follow WHO grading I to III (from low recurrence to high rates of recurrence with aggressive growth)
• Atypical meningioma, rhabdoid and malignant meningioma have greater risk of recurrence
• Brain invasion increases likelihood of recurrence but not indicator of malignant grade
• "Olfactory groove" is anterior to tuberculum sellae (distinction between tuberculum vs olfactory groove meningioma). Tuberculum sellae is bony elevation between chiasmatic sulcus and sella turcica. See tuberculum sellae meningioma here (external site)

MRI Findings

• T1 and T2 isointensity
• Most enhances with gadolinium
• Dural tail
• Signal voids in the lesion due to calcifications

Reference:

Cranial Base Center of Massachusetts General Hospital website 

Lipoma of Filum Terminale

Sagittal T1W image shows a T1 hyperintense mass at the filum terminale and a thin fatty strand extending from the tip of the conus medullaris to the coccyx.

Sagittal T2W image with fat suppression demonstrates signal loss of the mass, indicating presence of fat.

Facts:

• Abnormal retrogressive differentiation of pleuripotential cells found in distal caudal mass
• Mostly incidental, found in 5% of lumbar spine MRI but may be associated with tight filum terminale syndrome
• Fat is clearly separable from nerve roots and conus medullaris that terminates at above L2 level

Imaging

• Fat intensity mass (hyperintense T1, hyperintense T2, and progressive lower signal on greater T2 weighting)
• Can be intradural or extradural
• Intradural fatty filum is fusiform, tapering down toward where the filum pierces the dura
• Extradural fatty filum is often larger, more diffuse, elevating/distorting distal thecal sac

Reference:

Atlas SW. Magnetic resonance imaging of the brain and spine, 4th edition, 2009

Hemochromatosis

A&C: MRI out-of-phase imaging. B&D: MRI in-phase imaging
Signal decrease of the liver on B&D (in-phase images) when compared with A&C (out-of-phase images). Note innumerable Gandy-Gamna bodies in the spleen. 

Facts

• Hemochromatosis = iron overload
• Primary vs. secondary hemochromatosis
• Primary: autosomal recessive genetic disorder involving increased iron absorption. This is the most common genetic disease in white population
• Secondary: nongenetic causes of iron accumulation in organs such as cirrhosis, myelodysplastic syndrome, thalassemia
• Diagnosis is made with serum ferritin level and transferrin saturation index (but low sensitivity and specificity), genetic test and biopsy. Biopsy is reference standard
• Imaging such as non-contrast CT and MRI can be used to diagnose hemochromatosis but MRI is the best method

MRI Findings

• Iron accumulation in tissues cause local distortion of magnetic fields and spin relaxation, resulting in shortening T1, T2 and esp. T2* 
• Loss of signal intensity in affected organs proportional to iron deposition
• Dual-sequence (gradient in and out of phase) is typically used 
• Decreased signal intensity on in-phase images compared with out-of-phase images "opposite of hepatic steatosis"
• General MR protocols are not adequate to estimate hepatic iron concentration. Special sequences (i.e., GRE T2* with progressively longer echo times) are needed for this purpose
• Iron excess deposition may suggest etiology
• Reticuloendothelial system (i.e., liver and spleen): secondary hemochromatosis
• Parenchymal depositition pattern (i.e., liver only, possible pancreas): primary hemochromatosis or chronic anemia with insufficient erythropoiesis
• Mixed deposition pattern (atypical distribution): anemia+multiple blood transfusions

This patient has hemochromatosis secondary to cirrhosis. 

Reference:

Queiroz-Andrade M et al. MR imaging findings of iron overload. RadioGraphics 2009;29:1575-1589. 

Slideshow: Imaging of Thoracic Trauma

Imaging of Thoracic Trauma from Rathachai Kaewlai

Slideshow: Imaging of Abdominal Trauma

Imaging of Abdominal Trauma from Rathachai Kaewlai

Slideshow: Imaging of Traumatic Brain Injury

Imaging of Traumatic Brain Injury from Rathachai Kaewlai

Arachnoid Cyst

Axial T1W MR image shows a large T1 hypointense extra axial lesion in the left parietal region (arrow). 

Coronal T2GRE and T2W images demonstrate homogeneous T2 hyperintensity of the mass that follows CSF signal. There is compression of the adjacent gyri.  

Facts: Arachnoid Cyst

• Congenital lesion arising during development from splitting of arachnoid membrane
• Contains fluid usually identical to CSF
• Do not communicate with ventricles or subarachnoid space
• Lined with meningothelial cells 
• Incidence: 5 in 1,000 autopsies. 1% of intracranial masses
• Predominant male
• Mostly asymptomatic

Imaging:

• Extraaxial cystic mass with pressure effect to underlying brain
• Signal intensity follows CSF in all sequences
• No restricted diffusion
• Most common location (from highest to lowest frequency: Sylvian fissure (almost 50%), cerebellopontine angle, supracollicular, vermin, sella/suprasella

Reference:

Greenberg MS. Handbook of Neurosurgery, 7th edition. 2010

Blunt Traumatic Colon Perforation

Axial non contrast CT image of the abdomen shows a localized collection of air and high-density fluid (C) medial to the ascending colon (AC) and the site of colonic wall discontinuity (between arrows). Note skin and subcutaneous swelling/contusion of the right flank. 

Sagittal-reformatted CT image shows similar findings as  on the axial imaging. The entire length of the ascending colon (AC) is better appreciated and the collection (C) is located posteromedial to the colon within the retroperitoneal space. Colonic perforation was confirmed at surgery. 

Facts:

• Uncommon injury in blunt trauma
• Severe direct force is usually required to produce this injury, mostly from motor vehicle collision
• Often associated with other injuries, both intra- (liver, spleen, small bowel mesentery) and extra-abdominal (skeletal, facial, neurologic)
• CT may not be 100% sensitive. Findings could be overlooked in multiply-injured patients, large patients or if metallic monitoring/support devices are obscuring the area.
• "Normal" CT could be misleading when other factors such as physical examination is not taken into account. Re-review of images to look for subtle free fluid/air is essential in these cases.

CT Findings:

• Discontinuity of bowel wall
• Extraluminal contrast leakage
• Extraluminal air either intra- or retroperitoneal (nonspecific, can be seen after DPL, mechanical ventilation, barotrauma, etc)
• Intramural air
• Bowel wall thickening
• Bowel wall enhancement
• Mesenteric fat stranding
• Intraperitoneal and retroperitoneal fluid

References:

1. Barden BE et al. Perforation of the colon after blunt trauma. South Med J 2000;93(1)
2. Brody JM, et al. CT of blunt trauma bowel and mesenteric injury: typical findings and pitfalls in diagnosis. RadioGraphics 2000;20: 1525

Silicone Granulomas

MLO mammographic view of the left breast shows diffuse, markedly increased breast density throughout from prior direct silicone injection for breast augmentation. 

Transverse view of ultrasound of the left breast shows a cystic lesion (arrow) and multiple several lesions that has ill-defined borders and posterior acoustic shadowing (short arrows), representing silicone granulomas.

Axial non contrast CT shows multiple isodense soft tissue nodules in both breasts, some with thin rim of calcifications. 

Breast Augmentation with Direct Silicone Injection

• Was done in the USA in 1950s to 1960s but later prohibited in 1970s by the US FDA
• Liquid form of silicone was directly injected into breast parenchyma
• Adverse effects include lymphadenopathy, infection, formation of granulomatous masses (siliconoma) and fibrosis
• They make cancer difficult to find on physical examination and mammography 

Imaging Appearance of Free Silicone

• Ultrasound: variable appearance including 1) classic = highly echogenic pattern of scattered and reverberating echoes or "snowstorm" appearance, 2) lesion with acoustic shadowing, 3) hypoechoic masses almost indistinguishable from cysts surrounded by echogenic noise
• Mammography: distortion of breast parenchyma with increase density of the breast
• CT: soft tissue nodules with rim calcification
• MRI: low signal intensity on T1W with fat suppression, high signal intensity on T2W with water-suppression

Reference:

Caskey CI et al. Imaging spectrum of extracapsular silicone: correlation of US, MR imaging, mammographic and histopathologic findings. RadioGraphics 1999;19:S39-S51

Pancreatic Divisum

An MRCP image shows abnormal drainage of the main pancreatic duct and ventral duct into the minor papilla.

A diagram shows normal pattern of pancreatic duct drainage (label "normal") and pancreatic divisum. Several variants of pancreatic divisum exist but the "classic/typical" one is the MPD draining into the minor papilla while the VD draining into the major papilla along with the CBD. Santorinicele is a fusiform dilatation of the distal MPD before it enters the minor papilla. 

Facts: Pancreatic Divisum 

• Most common pancreatic anatomic variant, found 7% incidence at autopsy but frequencies differ at ERCP
• Controversial association with recurrent pancreatitis
• Results of non-fusion of ventral and dorsal pancreatic anlagen during embryonic time, therefore the ducts (ventral and dorsal ducts are not fused)
• Dorsal duct drains most of glandular parenchyma through minor papilla
• Ventral duct drains a portion of pancreatic head (including uncinate process) through major papilla

Imaging:

• Definitive diagnosis is made with ERCP. MRCP does have high sensitivity and specificity for diagnosis of divisum
• MDCT with thin section can be used to diagnose pancreatic divisum. Viewing images on PACS is essential for depiction of this condition and the assessment is possible only when the pancreatic duct is visualized.
• Important criterion = Dorsal duct seen from tail and body through the anterior aspect of the head, draining into minor papilla (located anterior to CBD and major papilla) while the ventral duct seen in posterior region of the pancreatic head and drains into duodenum together with CBD. Dorsal duct is larger than ventral duct and they are not communicated with each other. "Dominant dorsal duct sign"

Reference:

Soto JA, Lucey BC, Stuhlfaut JW. Pancreas divisum: depiction with multi-detector row CT. Radiology 2005; 235:503-508. 

Criteria and Consensus Method for Blunt Cervical Vascular Injury (BCVI) Screening with Imaging

According to the updated Guidelines for the Management of Acute Cervical Spine and Spinal Cord Injuries (published on March 2013, Neurosurgery 2013;72), 

• Computed tomography is the imaging study of choice for obtunded or un-evaluable patients with potential cervical spine injuries. (Level I)
• Computed tomographic angiography is recommended to assess for vertebral artery injury in selected patients who meet the modified Denver Screening Criteria after blunt cervical trauma. (Level I)

Currently accepted standard used for BCVI screening is that of Modified Denver Criteria applying to acute trauma patients suffering blunt cervical vascular injury with details listed below. In this post, they have been rearranged from the original description.

Injury Mechanisms/Patterns

• High-energy mechanism causing 1) displaced Le Fort II or III, or 2) complex mandible fracture
• Cervical hyperextension/rotation/flexion injury with 1) midface fracture, 2) complex mandible fracture or 3) closed-head injury and diffuse axonal injury

Symptoms

• Massive epistaxis
• Central or lateralizing neurologic deficit that is unexplained or incongruent with CT
• Transient ischemic attack or stroke after blunt neck trauma

Signs

• Expanding neck hematoma
• Honor syndrome
• Cervical vascular bruit in a patient less than 50 years old with blunt neck trauma
• Seat belt abrasion, hanging bruise, or unexplained contusion or hematoma of neck, resulting in significant cervical swelling or altered mental status

Findings on C-spine NCCT

• Upper cervical vertebral fracture (C1-C3)
• Cervical vertebral fracture extending through the transverse foramen
• Cervical vertebral subluxation
• Cervical spine fracture with cervical hyperextension/rotation/flexion injury

Findings on head NCCT

• Acute or subacute cerebral infarction
• Skull base fracture involving foramen lacerum, sphenoid, mastoid, or petrous bones

References: 

1. Biffl WL, Moore EE, Offner PJ, et al. Optimizing screening for blunt cerebrovascular injuries. Am J Surg 1999;178:517–22; 
2. Cothren CC, Moore EE, Biffl WL, et al. Cervical spine fracture patterns predictive of blunt vertebral artery injury. J Trauma 2003;55:811–3.
3. Neurosurgery 2013;72 Supplement 2. Full-text access is FREE

Solitary Pulmonary Nodule: Definition, DDx, and Evaluation with CT

Axial scan of the lung nodule in mediastinal window reveals a solid component of the nodule without calcification

Axial scan of the lung nodule in lung window shows a lobulated, smooth margin of the nodule

Definition of SPN

• Radiographic opacity of equal to or less than 3 cm
• At least two thirds of margins are surrounded by lung parenchyma
• Exclusion of lymph nodes (not always possible), atelectasis and postobstructive pneumonia

Differential Diagnosis

• Infectious: TB, pneumonia, abscess, fungus, etc
• Neoplastic: benign and malignant
• Vascular: AVM, infarct, aneurysm venous varix, hematoma
• Congenital: bronchogenic cyst, sequestration, bronchial atresia
• Inflammatory: rheumatoid arthritis, Wegener, sarcoidosis, microscopic angiitis
• Lymphatic: lymph node, lymphoma
• Outside the lungs: skin nodule, nipple shadows, rib fracture, pleural lesion
• Miscellaneous: rounded atelectasis, lipoid pneumonia, amyloidosis, etc

CT Evaluation

• Thin-section (1 mm) contiguous images through nodule are suggested
• Both lung and mediastinal windows obtained (lung window for margins/edges, mediastinal window for solid component)
• Low dose (less than 80 mAs) can be used for purpose of nodule characterization

CT Characteristics

• Growth rate: malignancy likely if doubling time = 20-400 days
• Size: malignancy likely if size > 3 cm
• Margin/border/edge: malignancy likely if lobulated, speculated, ragged, halo, notches
• Calcification: attenuation > 200 HU indicates presence of calcium in the nodule. No pattern of calcification specific for malignancy
• Cavitation: malignancy likely if irregular and thick (> 15 mm) wall

Our case: Solitary pulmonary nodule from a metastatic colon cancer

Reference:

Patel VK, Naik SK, Naidich DP, et al. A practical algorithm approach to the diagnosis and management of solitary pulmonary nodules. Part 1: radiologic characteristics and imaging modalities

Focal Hepatic Hot Spot Sign

An axial CT image shows a geographic area of hypervascularity (arrow) in segment IV of the liver. Note enlarged subcutaneous collateral vessels (arrowheads)

Facts: Focal Hepatic Hot Spot

• Focal area of enhancement in segment IV of liver due to presence of SVC obstruction
• Occurs due to portosystemic shunting between SVC and portal vein
• With SVC obstruction, blood may flow through internal mammary vein --> paraumbilical vein --> portal vein 
• Other causes of focal hot spots: Budd-Chiari syndrome (caudate lobe), liver abscess, hemangioma, FNH and HCC

Three Routes of Bypass of Venous Blood in Central Thoracic Venous Obstruction

1. Superior route: from subclavian vein to anterior jugular venous system (occuring in subclavian or brachiocephalic venous obstruction)
2. Posterior route: azygos-hemiazygos and paravertebral systems
3. Anterolateral route: like in our case, this is via anterior intercostal, internal mammary and long thoracic veins to IVC

Reference:

Maldjian PD, Obolevich AT, Cho KC. Focal enhancement of the liver on CT: a sign of SVC obstruction. J Comput Assist Tomogr 1995;19:316-8

Sternal Osteomyelitis

Chest radiograph of a patient who had sternal pain, fever and discharge shows no obvious bony abnormality.

Sagittal STIR and coronal T1W MR images demonstrate bone marrow edema with soft tissue changes in the sternum and right sternoclavicular joint (arrows). 

Facts:

• Uncommon infection of the sternum and sternoclavicular joint
• Usually affecting drug addicts, individuals with history of recent subclavian catheter placement, and patients with chronic debilitating illnesses
• Inciting organisms vary widely depending on demographics
• High failure rates of medical treatment alone. Typical treatment includes surgical debridement and en bloc removal

Imaging

• Radiograph is rarely helpful
• CT may show bone destruction but this may be late because damage begins in the joint. Surrounding soft tissue abnormalities are often a useful sign.
• MRI much more sensitive to detect joint and bone changes that are similar in findings to other areas of bone/joint infection

Reference: 

Shields TW et al. General Thoracic Surgery, 7th edition, 2009.

Renal Ultrasound for Elevated Serum Creatinine

A sagittal ultrasound image of the right kidney shows a normal-sized kidney with normal parenchymal echogenicity in a patient with acute renal failure. 

What clinicians want to know is whether elevated serum creatinine "acute or chronic" 

• This information is important to narrow differential diagnosis, urgency of investigation and treatment. 
• Chronicity of renal dysfunction can be determined with 1) a search for previous measures of renal function (i.e., old labs), 2) clinical history (i.e., recent onset of acute illness, oliguria that would suggest acute renal failure), 3) daily deterioration of renal function (suggestive of acute renal failure - ARF), 4) ultrasound
• ARF can be prerenal, renal or postrenal

Why Ultrasound?

• Ultrasound can help determining the kidney size. Small renal size (less than 8 cm in adults) is suggestive of CRF
• Demonstrate hydronephrosis, suggesting a postrenal cause. Note that to produce ARF, both kidneys must be affected (i.e., bilateral ureteric obstruction or bladder outlet obstruction, or hydronephrosis of a single functioning kidney)
• To exclude obstruction, US should be done as early as possible. But US is not necessary if there are "clear reversible causes on initial assessment + Rx instituted + clear evidence of prompt response with return to normal renal function within a few days"
• Increased echogenicity of renal cortex is not a sensitive measure of renal function. When present, it is more commonly seen in tubulointerstitial disease rather than glomerular disease

Limitations of Ultrasound

• No hydronephrosis is not equal to no obstruction. False negative study can occur 1) in the first few days of obstruction because the collecting system is relatively noncompliant, 2) if ureters and collecting systems are encased by tumor or fibrosis
• Detection of hydronephrosis can be difficult in patients with cystic kidney disease

Reference:

Baxter GM, Sidhu PS. Ultrasound of the urogenital system, 2006.

Gallbladder Cholesterolosis

Longitudinal US image of the gallbladder demonstrates multiple tiny echogenic spots within the wall with comet-tail artifacts. No evidence of gallbladder wall thickening. 

Facts:

• Other names: cholesteatosis, strawberry gallbladder
• Common, degenerative, proliferative changes of gallbladder
• Usually in females during their 4th and 5th decades
• Usually asymptomatic
• Not associated with increased risk of malignancy, cholelithiasis or cholecystitis

Differentiation from Adenomyomatosis:

• May be difficult at times because they may coexist and are believed to be a continuum of same pathology
• In cholesterolosis, the gallbladder has normal size, shape, lumen and often normal wall thickness

Reference:

Schmidt G. Differential diagnosis in  ultrasound imaging: A teaching file, 2006

Early Signs of Ischemic Brain Injury on Noncontrast CT

Axial noncontrast CT images of the brain of two different patients presenting with acute stroke within 3 hours of symptom onset. The top row is images in a "brain" window, while the bottom row shows images in an "acute stroke" window. Early ischemic changes (cortical ribbon sign) of the right posterior inferior cerebral artery (left images) and right middle cerebral artery (right images) are much better appreciated on the acute stroke window.  

Loss of gray-white differentiation

• Lenticular obscuration: loss of distinction among basal ganglia nuclei
• Insular ribbon sign: blending of densities of cortex and white matter of insula
• Cortical ribbon sign:  blending of densities of cortex and white matter of other lobes

Swelling of gyri producing sulcal effacement

Detectability

• Seen on less than 1/3 of patients imaged within 3 hours of symptom onset
• Detection influenced by infarct size, severity and time between symptom onset and imaging
• Large interobserver variability, which may be improved by the use of a structured scoring system such as Alberta Stroke Program Early CT Score (ASPECTS) or the CT Summit Criteria, as well as the use of better CT windowing and leveling (use of "acute stroke" window)

Implications of these signs to management

• More rapid these signs become evident, the more profound the degree of ischemia
• Presence, clarity and extent of these signs on noncontrast CT correlates with higher risk of hemorrhagic transformation after Rx with fibrinolytic agents
• Involvement of greater than 1/3 of MCA territory increases risk of intracranial hemorrhage, shown in a European trial in patients of less than 6-hour symptom onset. This criterion has been used as an exclusion from entry in several trials evaluating the benefit of IV fibrinolytic therapy in the 3- to 4.5-hour window

Reference:
Jauch EC, et al. Guidelines for the early management of patients with acute ischemic stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2013 (January)

Updated Nomenclature of Vasculitides

A sagittal-curved-reformatted CT image of the aorta of a 31-year-old man demonstrate extensively calcified intima and focal narrowing of the mid/distal thoracic aorta, consistent with Takayasu arteritis.

Very recently, the international consensus conference addressed the revision of the nomenclature of systemic vasculitides as follows:

• LARGE-vessel vasculitis: Takayasu arteritis and giant cell arteritis
• MEDIUM-vessel vasculitis: polyarteritis nodosa, Kawasaki disease
• SMALL-vessel vasculitis: ANCA-associated vasculitis (microscopic polyangiitis, Wegener, Churg-Strauss), immune complex vasculitis 
• VARIABLE-vessel vasculitis: Behcet disease, Cogan syndrome
• SINGLE-ORGAN vascuiltis: cutaneous leukocytoclastic angiitis, primary CNS vasculitis, and others
• Vasculitis associated with systemic diseases such as lupus, rheumatoid arthritis and sarcoid
• Vasculitis associated with probable etiology (e.g., associated with viral hepatitis, drugs) 

Categorization by vessel size reflects the arteries those are predominantly affected. Vasculitis in each category can affect any size artery. 

Reference:

Jennette JC, et al. 2012 revised international chapel hill consensus conference nomenclature of vasculitides. Arthritis Rheum 2013;65:1-11.

Endovascular Treatment Not Superior to Intravenous TPA for Acute Stroke

A study published in the New England Journal of Medicine (6 Feb 2013) did not find different outcomes of acute stroke patients treated with endovascular therapy vs intravenous TPA

Background

• IV recombinant tissue plasminogen activator (t-PA) is the standard treatment for acute ischemic stroke
• Endovascular (intraarterial) treatment has higher recanalization rates but whether this translates into more favorable clinical outcome is unknown
• Prior trials of endovascular treatment showed promising results but there were problems with 1) limited generalizability, 2) lack of comparison between endovascular Rx and IV t-PA, 3) endovascular Rx was not assessed as a multimodality procedure

Study Methods and Results

• Multicenter, open-treatment clinical trial with a blinded end point
• Questions: whether outcomes were better with endovascular Rx than with IV t-PA
• Included patients are between 18-80 years, with a clearly defined time of stroke onset that was less than 4.5 hours (for IV t-PA) or 6 hours (for endovascular Rx)
• 362 patients with acute ischemic stroke were randomized to either endovascular Rx (IA thrombolysis with rt-PA, mechanical clot disruption or retrieval, or a combination of these) or to IV rt-PA
• Primary outcome = disability-free survival at 90 days, secondary outcome = proportion of patients with mild neurologic deficit or none and several safety measures
• Disability-free survival at 90 days = 30% in endovascular group, 35% in IV group. This did not change after adjustment for age, sex, stroke severity or presence of atrial fibrillation

Reference:
Ciccone A et al. Endovascular treatment for acute ischemic stroke. N Eng J Med 2013 Feb 6.
Read the full study HERE

Limbus Vertebra

LS spine x-ray, sagittal-reformatted CT and sagittal T1W MR images demonstrate a limbus vertebra in the anterosuperior corner of L4 vertebral body in this 32-year-old woman.

Facts

• Intrabody herniation of disc material at the margin of the endplate, occurs during spinal growth before skeletal maturity
• Herniation of nuclear material through the cartilaginous junction zone of ring apophysis may isolate this ossification center from the body margin, inhibiting osseous fusion to the vertebral body
• Up to 5% of cadavers
• Generally asymptomatic

Imaging

• Smoothly corticated triangular fragment of bone at the corner of the vertebral body
• Most common in midlumbar spine (L2-4) but can be at any level including cervical spine
• Most common at the anterosuperior corner of the vertebral body
• Typically displaced farther from margin of vertebral body

References:

Ghelman B, Freiberger RH. The limbus vertebra: an anterior disc hernation demonstrated by discography. AJR 1976; 127:854-855

Atypical Hepatic Hemangioma - Echoic Border

Ultrasound images of the liver show a round hypoechoic nodule (arrow, calipers) in the right lobe with an echoic border. Background fatty liver is noted. 

Hemangioma with Echoic Border

• Frequent atypical pattern at ultrasound
• Can have either thick echoic rind or thin echoic rim
• Internal echo is at least partially hypoechoic, which is assumed to represent previous hemorrhage, necrosis, scarring or myxomatous change

Reference:

Vilgrain V, et al. Imaging of atypical hemangiomas of the liver with pathologic correlation. Radiographics 2000; 20:379.

Extraosseous Myeloma

Axial PET/CT images show a large homogeneous soft tissue mass in the lett buttock involving the gluteal muscles, which demonstrates significant FDG avidity. 

Extraosseous Myeloma

• 10-16% of patients with multiple myeloma
• Rising incidence possibly due to better imaging techniques and increased survival of patients with myeloma
• More common in younger myeloma patients and more aggressive subtypes
• Shorter survival and shorter progression-free survival (than patients without extraosseous involvement)
• Has been integrated into an updated version of Durie-Salmon staging system

How to Image Patients with Myeloma

• Skeletal survey (current minimum standard)
• Whole-body PET/CT vs. whole-body MRI for newly diagnosed myeloma and with no findings or limited findings on skeletal survey (two different methods have been suggested by different authorities) to assess for occult involvement

Imaging Appearances

• Soft tissue: nodules in subcutaneous tissues and muscles (like in our case)
• Reticuloendothelial system: lymph node enlargement in multiple stations
• Liver: hepatomegaly, low-attenuation liver lesions without enhancement
• CNS: leptomengineal process 
• Lungs: lung nodules, masses, interstitial infiltration
• Kidneys: masses, diffuse enlargement
• Peritoneum: masses

Reference:

Hall MN, Jagannathan JP, Ramaiya NH, et al. Imaging of extraosseous myeloma: CT, PET/CT and MRI features. AJR 2010; 195:1057-1065. 

Happy New Year 2013!