Meniscal Bucket-Handle Tear

Fig: Coronal T2 image (with fat suppression) shows a displaced fragment (arrow) of medial meniscus into the intercondylar notch of the knee. Note intact ACL (arrowheads).

What is 'Bucket-Handle' Tear?

• Longitudinal, peripheral tear of the meniscus with displacement of fragment toward the intercondylar notch of the knee
• Leads to locked knee and surgery (debridement or repair) is necessary
• If occurs at the outer 1/3 (white/white zone), only debridement; if middle and peripheral third (white/red, red/red zones) require repair
  

How to Diagnose?

• Using MRI with coronal and sagittal planes
• Look for extra-structure in the intercondylar notch on coronal image!
• Double PCL (posterior cruciate ligament) on sagittal image
  
• Donor meniscus (usually medial) look smaller than usual (key to differentiate bucket-handle tear from normal oblique intermeniscal ligament)

Reference:
Stoller DW, et al. Diagnostic imaging: orthopedics. 2004

Crazy-Paving Pattern

Fig. Axial CT of the chest shows diffuse bilateral ground-glass opacities superimposed by interlobular septal thickening (arrowheads) and intralobular lines (blue arrows). Note a left chest tube used to treat left pneumothorax, which brought this patient to the hospital.

What is "Crazy-Paving" Pattern?

• Ground-glass opacity superimposed with interlobular septal thickening and intralobular lines
  
• Can be scattered or diffuse
  
• Can be caused by alveolar filling process, interstitial process, or a combination

What Can Cause "Crazy-Paving" Pattern?

• CLASSIC: Pulmonary alveolar proteinosis 
  
• COMMON: Pneumocystis jirovecii pneumonia (PCP), pulmonary edema (ARDS), pulmonary hemorrhage
  
• NOT COMMON: Bronchioloalveolar carcinoma, alveolar sarcoidosis, nonspecific interstitial pneumonitis (NSIP), Cryptogenic organizing pneumonia (COP), lipoid pneumonia
  

Our case is a patient with biopsy proven pulmonary alveolar proteinosis.

Reference:

1. Rossi SE, et al. "Crazy-Paving" Pattern at Thin-Section CT of the Lungs: Radiologic-Pathologic Overview. Radiographics 2003;23:1509.

2. Johkoh T, et al. Crazy-paving Appearance at Thin-Section CT: Spectrum of Disease and Pathologic Findings. Radiology 1999;211:155.

Who is Aunt Minnie?

Beside 'Aunt Minnie' as a popular radiology website, do you know who really is Aunt Minnie?

A few communications in Radiology and AJR provided the answer.

Aunt Minnie

• Constellation of observations virtually pathognomonic of an entity (usually of an unusual or unexpected disease)
• Subliminal or subconscious pattern recognition of disease (similar to recognizing Aunt Minnie among a large group of similar women)
• The term attributed to two figures in radiology history: Ed Neuhauser (previous Chief at Children Hospital Boston) and Ben Felson (neither had an aunt named Minnie)

Reference:
Hall, et al. Gestalt: Radiology's Aunt Minnie. AJR 2008 (October)

Image source: www.auntminnie.com

Traumatic Aortic Injury (TAI)

Fig.1: Portable chest radiograph shows widening of the superior mediastinum (two-sided arrow), deviation of the NG tube (arrowheads) and trachea to the right.
Fig.2: Axial CT with IV contrast shows a large periaortic hematoma (stars) displacing the NG tube (arrowhead) to the right.
Fig.3: Axial CT at the level below the arch demonstrates a pseudoaneurysm (red arrow) anterior to the true lumen (red arrowhead). Hematoma (stars) and NG tube (yellow arrowhead)

Radiographic Findings

• Widening of superior mediastinum (subjective 'eyeball' estimation)
• Blurring of aortic contour
• Deviation of nasogastric tube to the right
• Normal - not common but x-ray can be normal if there is no or minimal periaortic hematoma (Normal chest radiograph does not exclude TAI in a trauma patient with suspicious mechanism)
  

CT Findings

• Direct signs: Pseudoaneurysm, intimal flap, irregularity of aortic wall, pseudocoarctation, thrombus with in the wall
• Indirect sign: Periaortic hematoma (not isolated anterior mediastinal hematoma)

Do We Need Aortography?

• Studies of MDCT (16- and 64-MDCT) showed accuracy of near 100% using surgery or follow-up CT as standard references
• When a direct sign is present, TAI can be diagnosed confidently without aortography
• Aortography can be reserved for equivocal cases, evaluation of aortic branch vessels and endovascular therapy
  

Reference:
1. Kaewlai, et al. MDCT of blunt thoracic trauma. Radiographics 2008 (October)
2. Steenburg, et al. Acute traumatic thoracic aortic injuries: experience with 64-MDCT. AJR 2008 (November)

Chest Wall Fat Mimicking Tumor

Fig.1: Chest radiograph shows abnormal opacity in the periphery of the right upper lobe, which is broad-based to the pleura and partially well defined on the side opposing the lung. Based on this appearance, pleural location is likely. Differential diagnosis is broad and may include pleural effusion (loculated), thickening, plaque, or mass.
Fig.2: Axial CT shows an extrapleural fat (arrowheads) deep to the costal margin.

Facts

• Extrapleural costal fat can be mistaken for pleural lesions including plaque and tumor
• Thickening of the extrapleural costal fat can be associated with lung scarring
• CT is an easy tool to use differentiate between fat and soft tissue mass
• Fat can be drawn into fissures (as seen on Fig.1). It looks as if it is in the pleural space, but it is covered by parietal pleura - therefore is extrapleural
  

Reference:
Fisher ER, et al. Extrapleural fat collections: pseudotumors and other confusing manifestations. AJR 1993 (July)