Kartagener Syndrome

Figure 1: Frontal chest radiograph demonstrates dextrocardia (cardiac apex pointing to the right with right aortic arch - arrowheads), bibasilar coarse reticular opacities and loss of volumes in the lower lungs in a patient with Kartagener syndrome.
Figure 2: Coronal reformatted CT image confirms the presence of extensive bibasilar bronchiectasis (arrows) and situs inversus. Bronchiectasis in patients with this syndrome tends to involve the dependent parts of the lungs.

Facts: Kartagener Syndrome

• Genetically transmitted (autosomal recessive) syndrome characterized by bronchiectasis, situs inversus and chronic sinusitis
• Genetic disorder first described in 1904, but identified as a syndrome by Manes Kartagener, a Swiss internist, in 1933
• It is a subtype of primary cilia dyskinesia
• Incidence 1:32000 live births
• Abnormal function of cilia is believed to be responsible for visceral asymmetry (abnormal movement of cilia in certain embryonic epithelial tissues), respiratory disease, etc.

Diagnosis

• Onset of upper and lower respiratory tract symptoms shortly after birth in the presence of situs inversus
• Family history of primary ciliary dyskinesia or Kartagener syndrome
• Confirmation with biopsy of respiratory mucosa or microscopic examination of sperms
• Other clinical signs: chronic rhinitis with nasal polyposis, agenesis of frontal sinuses, repeated otitis media, bronchiectasis (usually dependent parts of the lungs in contrast to cystic fibrosis that tends to affect the upper lobes), situs inversus (complete or partial)

Reference:

Bissonnette B, Luginbuehl I, Dalens BJ. Syndromes: rapid recognition and perioperative implications, 2006.

Right Lower Lobe Atelectasis

Figure 1: Chest radiograph shows loss of right lung volume, abnormal opacity in the right lower lung obscuring the right hemidiaphragm, inferior displacement of the major fissure (arrows) and right hilum.

Figure 2: Coronal CT image revealed a large right hilar mass (star) resulting in right lower lobe atelectasis.

Imaging Findings

• Lower lobe atelectasis occurs in posterior, inferior and medial direction because of the presence of pulmonary ligaments
• Medial/inferior shift of major fissure; minor fissure may not shift
• Obscuration of hemidiaphragm, paraspinal interface; right heart border still visible
• Vertical orientation of lower lobe bronchi
• Inferior and medial displacement of ipsilateral hilum
• Triangular opacity of atelectatic lobe, with apex toward the hilum and base toward the hemidiaphragm

Our case: Right hilar mass causing obstructive right lower lobe atelectasis (squamous cell carcinoma)

Reference:

Parker MS, Rosado de Christenson ML, Abbott GF. Teaching atlas of chest imaging, 2006.

Follow RiTradiology on Facebook, Twitter or Google Friend Connect

Visit RiT Illuminations to view nice pictures of your colleague

Blunt Traumatic Vertebral Artery Dissection

Fig.1: Axial CT image of the cervical spine shows a fracture of the right facet (arrows) extending to the transverse foramen of C6 in a neurologically intact blunt trauma patient.
Fig.2: Subsequent CT angiography of the neck shows a long-segment occlusion (red arrows) of the right vertebral artery from C6 up to base of the skull.

Why Screening for Blunt Cerebrovascular Injury (BCVI) in Trauma Patients?

• If left untreated, carotid and vertebral artery injury can have a stroke rate ranging from 3-100% and 6-100% respectively
• Stroke rate by BCVI depends on grade of injury: the higher the grade, the higher stroke rate
• Screening protocols based on patient injury patterns and mechanism of injury have been instituted prior to neurologic sequelae to identify these injuries in asymptomatic patients and to initiate stroke-preventive treatment.
• Based on current studies, early anticoagulant therapy reduces stroke rates and prevents neurologic morbidity from BCVI

Facts: Denver Screening Criteria

• General guidelines to determine which blunt cerebrovascular injury (BCVI) patients should be evaluated for arterial injury.
• Signs/symptoms of BCVI: arterial hemorrhage, cervical bruit in patient less than 50 years of age, expanding cervical hematoma, focal neurologic deficit, neurologic exam incongruous with head CT scan findings, stroke on secondary CT scan
• Risk factors for BCVI: high-energy transfer mechanism with LeFort II or III fracture, cervical spine fracture pattern (subluxation, fracture extending into the transverse foramen, fractures of C1-C3), basilar skull fracture with carotid canal involvement, diffuse axonal injury with a Glasgow Coma Scale score less than 6, near hanging with anoxic brain injury

Facts: Denver Grading Scale for BCVI

• Grade I: irregularity of the vessel wall or a dissection/intramural hematoma with less than 25% luminal stenosis
• Grade II: intraluminal thrombus or raised intimal flap is visualized, or dissection/intramural hematoma with 25% or more luminal narrowing
• Grade III: pseudoaneurysm
• Grade IV: vessel occlusion
• Grade V: vessel transection

Injury Patterns on Imaging That Should Raise a Suspicion for BCVI

• Interfacet subluxation/dislocation
• Fracture lines reaching an arterial structure
• C1-C3 fracture
• Basilar skull fracture with carotid canal involvement
• LeFort II or III fracture due to high-impact trauma

Reference:

1. Cothren CC and Moore EE. Blunt cerebrovascular injuries. Clinics 2005;60:489-496.

2. Delgado Almandoz JE, Schaefer PW, Kelly HR, et al. Multidetector CT angiography in the evaluation of acute blunt head and neck trauma: a proposed acute craniocervical trauma scoring system. Radiology 2010 (published online before print December 17, 2009).

Follow RiTradiology on Facebook, Twitter or Google Friend Connect

Visit RiT Illuminations to view nice pictures of your colleague

Zenker's Diverticulum

Lateral view of barium esophagogram shows a large diverticulum (arrow) arising in the midline from the posterior wall of the cervical esophagus (arrowheads).

Facts:

• Most common form of esophageal diverticulum
• Protrusion of mucosa posteriorly just proximal to cricopharyngeus muscle
• Believed to be due to oropharyngeal discoordination and upper esophageal sphinctor dysfunction
• Many patients are asymptomatic, but can present with dysphagia, regurgitation, throat discomfort
• Usually in 5th to 8th decades of life

Diagnosis and Treatment

• Barium esophagogram is an optimal method to demonstrate the diverticulum
• Intradiverticular filling defects usually represent food, but carcinoma is in the differential diagnosis.
• Large diverticulum can present on chest radiograph as a superior mediastinal mass
• Endoscopy not required, but if it is to be done it should be done with caution because of a risk of inadvertent perforation
• Treatment: diverticulectomy with or without cricopharyngeal myotoma, endoscopic stapling and division of common wall between cervical esophagus and diverticulum

Reference:

Grendell JH, et al. Current Diagnosis & Treatment in Gastroenterology, 2nd edition, 2003.

Follow RiTradiology on Facebook, Twitter or Google Friend Connect

Visit RiT Illuminations to view nice pictures of your colleague

Cerebral Toxoplasmosis

Axial T1W MR image post contrast shows a ring enhancing mass with "target appearance" in the left lentiform nucleus with marked surrounding edema, resulting in midline shift in an AIDS patient.

Facts: Cerebral Toxoplasmosis

• Infection with parasite Toxoplasma gondii
• Manifested clinically as acute, symptomatic infection or reactivation of latent infection in immunocompromised hosts. It can be seen as a self-limited infection in immunocompetent hosts, or congenital infection
• Etiology: ingestion of raw or undercooked meat, food or water containing tissue cysts or oocytes, transplacental, blood transfusion, solid organ transplantation
• In immunocompromised hosts, 50% presents with CNS disease (encephalitis, meningoencephalitis, seizures, mental status change, etc)

MR Imaging Appearance

• Ring enhancing lesions with marked surrounding edema
• Most common location = basal ganglia and gray-white matter junction of cerebral hemisphere
• Low signal on T1WI, intermediate/low/high signal on T2WI. May be hemorrhagic

Distinguishing Features from Lymphoma

• Toxoplasmosis and lymphoma are two most common enhancing intracranial masses in AIDS patients
• Toxoplasmosis tends to be multiple, and lesions are usually smaller than lymphoma
• On conventional MRI, they may look similar.
• On DWI/ADC, toxoplasmosis shows less restriction than in lymphoma.
• On MR spectroscopy, toxoplasmosis shows increased lactic and lipid peak (opposite in lymphoma)
• Toxoplasmosis is metabolically inactive on FDG-PET
• After 2-4 weeks of antitoxoplasma treatment, some healing should be seen on imaging of toxoplasmosis

Reference:

1. Lin EC, et al. Practical differential diagnosis for CT and MRI, 2008.
2. Domino FJ. 5-minute Clinical Consult 2007.
3. Castillo M. Neuroradiology companion: methods, guidelines, and imaging fundamentals, 3rd edition, 2006.

Follow RiTradiology on Facebook, Twitter or Google Friend Connect