Edi Catheter (NOT MRI SAFE)

Edi (Electrical activity of the diaphragm) catheters are nasogastric or orogastric catheters that estimate the neural respiratory drive and send that information to the mechanical ventilator. The ventilator uses that information to control respiration, guided by the patient's own neural control of breathing. This concept is called Neurally Adjusted Ventilatory Assist or NAVA).

The sensor part of the Edi Catheter is positioned in the esophagus at the level of the diaphragm (video on placement of the catheter). The Edi catheter from Maquete can also act as a normal nasogastric feeding tube and has a barium sulfate strip for identification on x-rays, but you wouldn't recognize it as anything other than a normal NG or OG tube unless you recognize that it looks different from the rest of the catheters used in your institution.

The above is kind of important because the catheter is NOT CONSIDERED SAFE FOR MRI.

References

Stein H, Hall R, Davis K, White DB. Electrical activity of the diaphragm (Edi) values and Edi catheter placement in non-ventilated preterm neonates. J Perinatol. 2013 Sep;33(9):707-11.

Costochondritis

Costochondritis, as its implies, is a nonspecific term for inflammation of the costal cartilage. The problem with this definition is that it implies a non-specific process, where inflammation can be caused by any number of pathological processes, including trauma, infection, or radiation.

The clinical entity of costochondritis, on the other hand, has specific features:

• Self-limited
• Usually multiple affected levels
• Can occur at the costochondral junction or at the chondrosternal joints
• No swelling or induration on physical examination
• Pain that is reproduced by palpation and may radiate on the chest wall

This definition differentiates costochondritis from the much rarer Tietze syndrome (TS). In TS, the inflammatory process causes visible enlargement of the costochondral junction(s) and is most commonly isolated to a single rib (usually the 2nd, but can also involve the 3rd rib). TS can be caused by infectious, rheumatologic, and neoplastic processes. The infection is usually associated with trauma (e.g., stab wounds, iatrogenic) or with intravenous drug use.

Costochondritis is relatively common, and can be seen is as many as 14% of adolescents and 13 to 36% of adults with chest pain.

References

Proulx AM, Zryd TW. Costochondritis: diagnosis and treatment. Am Fam Physician. 2009 15;80(6):617-20.

Sarcoid-Like Reaction in Oncology

Sarcoid is thought to develop in predisposed individuals by a cross-reaction to tumor, bacterial, viral, or inorganic antigens or immunogenes. Patients respond by forming noncaseating granulomas, which are most commonly intrathoracic. Sarcoid-like reaction (SLR) refers to the development of noncaseating granulomas in patients who do not fulfill the criteria for systemic sarcoidosis.

In oncological patients, SLR most commonly occurs in the lymph nodes draining a malignant tumor, but can also be observed in the organ of tumor origin and distant tissues. It develops after antineoplastic treatment with biologic modifiers (e.g., interferon and interleukin-2), single or combination chemotherapy agents, or even after surgery without chemotherapy.

The patient above has a history of melanoma of the left lower extremity with recurrent ipsi- and contra-lateral inguinal nodal involvement that has been treated with surgery (most recently 8 months ago) and chemotherapy in the remote past (cisplatin, vinblastine, and dacarbazine). The PET from 3 months ago (left panel) was clear. The new PET (right panel) shows new supraclavicular (red arrow), intra-thoracic (yellow arrows), and upper abdominal (blue arrow) adenopathy. The lymph nodes are highly FDG-avid and most prominent in the chest, where we see the symmetric hilar and mediastinal adenopathy typical of sarcoid and would be atypical for nodal involvement from lower extremity melanoma. It is important to keep SLR in mind in order to avoid over-calling disease progression. This can be more problematic in cases of intrathoracic neoplasms that would be expected to recur in the chest and involve hilar and mediastinal lymph nodes. Symmetrical hilar involvement can be a helpful hint in these cases.

References

• Inoue K, Goto R, Shimomura H, Fukuda H. FDG-PET/CT of sarcoidosis and sarcoid reactions following antineoplastic treatment. Springerplus. 2013 Dec;2(1):113.
• Tchernev G, Tana C, Schiavone C, Cardoso JC, Ananiev J, Wollina U. Sarcoidosis vs. Sarcoid-like reactions: The Two Sides of the same Coin? Wien Med Wochenschr. 2014 Jul;164(13-14):247-259.

The Deep Sulcus Sign

The deep sulcus sign refers to lucency of the lateral costophrenic angle in a supine patient with a pneumothorax. The above images demonstrate the deep sulcus sign at the left costophrenic angle in a pediatric patient. A left lateral decubitus film (second image) confirmed the presence of a pneumothorax.


REFERENCES
Kong A. The deep sulcus sign. Radiology 2003;28:415-6.

Killian Jamieson Diverticulum

Killian is usually mentioned when discussing the Killian's dehiscence which is the gap in the posterior hypopharynx where the muscle fibers of the cricopharyngeus muscle and inferior constrictor muscle diverge. This site is where Zenker's diverticula occur.

The Killian-Jamieson space is below the cricopharyngeus muscle and lateral to the longitudinal muscle of the esophagus. This muscular gap is the location of the rarer Killian-Jamieson diverticulum. Fluoroscopy will show an outpouching along the anterolateral esophagus inferior to the cricopharyngeus muscle (as opposed to along the posterior esophagus and superior to the cricopharyngeus muscle in the case of a Zenker's diverticulum). 

REFERENCES

Rubesin SE and Levine MS. Killian-Jamieson diverticula. AJR Am J Roentgenol 2001;177:85-9.

Lipomatous Hypertrophy of the Interatrial Septum Revisted

A companion case of lipomatous hypertrophy of the interatrial septum previously discussed here. This lesion can mimic fat containing neoplasms including myxomas, rhabdomyomas, rhabdomyosarcomas, and liposarcomas.


REFERENCES
Fan CM, Fischman AJ, Kwek BH, et al. Lipomatous hypertrophy of the interatrial septum: increased uptake on FDG PET. AJR Am J Roentgenol 2005;184:339-42.

Thoracic Involvement in Amebiasis

• Amebiasis is an infection due to the protozoan Entamoeba histolytica
• Most common manifestation is liver abscesses
• Thoracic involvement is either through direct extension from the liver (most common) or via hematogenous spread
• Pleural effusions are common, may be an empyema if the effusion is due to a ruptured hepatic abscess
• Pneumonia with formation of hepatobronchial or bronchobiliary fistula
• Pericarditis is more common when the left hepatic lobe is involved and can cause cardiac tamponade
• Invasion of the IVC may cause pulmonary emboli

REFERENCES

Martinez S, Restrepo CS, Carrillo JA, et al. Thoracic manifestations of tropical parasitic infections: a pictorial review. Radiographics 2005;25:135-55.

Lady Windermere Syndrome

An 88 year old Caucasian woman presents to the ER with hemoptysis. CT scan reveals bronchiectasis in the medial segment of the right middle lobe with scattered peripheral nodules. Findings are typical for  Mycobacterium avium intracellulare complex (MAIC). This is an atypical mycobacterial infection seen in elderly females. It is thought that the imaging findings may be due to chronic suppression of a cough leading to retained secretions in the dependent portions of the ventral lung fields.


REFERENCES
Rossi SE, Franquet T, Volpacchio M, et al. Tree-in-bud pattern at thin-section CT of the lungs: radiologic-pathologic overview. Radiographics 2005;25:789-801.

Fibrosing Mediastinitis

Fibrosing mediastinitis (FM) is due to abnormal proliferation of collagen and fibrous tissue in the mediastinum. It can present either focally or diffusely with the latter type involving multiple mediastinal compartments. Causes are either idiopathic or secondary to granulomatous infection (Histoplasmosis in the United States). 

FM is the most common benign cause of SVC obstruction. Imaging findings include a hilar or mediastinal mass causing mediastinal widening. The right paratracheal region is the most common location for occurrence of a mass. Focal FM tends to have calcified masses whereas calcification is less common in diffuse FM. 

Differential considerations include:

• lymphoma
• bronchogenic carcinoma - usually older patient, doesn't calcify

REFERENCES
Rossi SE, McAdams HP, Rosado-de-Christenson ML, et al. Fibrosing mediastinitis. Radiographics 2001;21:737-57.

Traumatic Aortic Transection

The above images are from a patient who suffered a motor vehicle accident. The axial image demonstrates a mediastinal hematoma and an intimal flap in both the ascending and descending aorta. The sagittal image better demonstrates the continuity of the intimal flap along with aortic contour abnormality. These findings are pathognomonic for acute traumatic aortic injury.

A finding that is not demonstrated on these images is active extravasation of intravenous contrast material. Its presence would be concerning for exsanguination. 


REFERENCES
Kuhlman JE, Pozniak MA, Collins JC, et al. Radiographic and CT findings of blunt chest trauma: aortic injuries and looking beyond them. Radiographics 1998;18:1085-1106.
Steenburg SD, Ravenel JG, Ikonomidis JS, et al. Acute traumatic aortic injury: imaging evaluation and management. Radiology 2008;248:748-62.

Sequelae of Tuberculous Pleural Disease

Tuberculosis can have varied presentations in the chest including pleural effusions. Tuberculous pleuritis has a high incidence in immunosuppressed patients, especially those with HIV. Complications of tuberculous pleural disease include:

• pleural thickening
• fibrothorax - calcified and thickened pleura, loss of lung volume, adjacent rib hypertrophy, epipleural fat pads, often unilateral
• chronic persistent pleural effusion - content of the effusion are near soft tissue density
• empyema necessitans - decompression of an empyema through the chest wall, fistulous tract between a pleural collection and an extrathoracic fluid collection may be seen, other sites of extension include breast, esophagus, pericardium, vertebral column, retroperitoneum, flank, groin
• bronchopleural fistula - air/fluid collections in the pleural space, pleural thickening, atelectasis and bronchiectasis in ipsilateral lung, fistulous connection may be seen

REFERENCES

Heffner JE, Klein JS, Hampson C. Diagnostic utility and clinical application of imaging for pleural space infections. Chest 2010;137(2):467-79.

Jung-Ah C, Hong KT, Oh YW, et al. CT manifestations of late sequelae in patients with tuberculous pleuritis. AJR Am J Roentgenol 2001;176(2)441-5.

Blunt Diaphragmatic Rupture

Traumatic blunt diaphragmatic rupture (BDR) is most commonly due to motor vehicle accidents (as was the case in the above patient). The left hemidiaphragm is more commonly injured than the right due to protective effects of the liver. Prompt diagnosis of BDR is important due to potentially life threatening complications if this injury is missed. Common signs indicating BDR on plain films and CT are as follows:

Radiographic signs:

• loss of diaphragmatic continuity
• intrathoracic herniation of a hollow viscus (stomach, bowel) or solid organ (liver, spleen)
• visualization of nasogastric tube tip in thorax
• collar sign - focal constriction of a herniating viscus at the site of diaphragmatic tear

CT signs:

• discontinuity of diaphragm
• collar sign (as above)
• dependent viscera sign - herniated viscera is no longer freely suspended in the abdominal cavity and falls dependently (along the posterior ribs)

REFERENCES
Desir A and Ghaye B. CT of blunt diaphragmatic rupture. Radiographics 2012;32:477-98.
Iochum S, Ludig T, Walter F, et al. Imaging of diaphragmatic injury: a diagnostic challenge?. Radiographics 2002;22:S103-16.

Cystic and Solid Lesions of the Cardiophrenic Space

The cardiophrenic space is located at the base of the mediastinum and is defined by the base of the heart, the diaphragm, and the chest wall. Normally, this space is occupied by fat although both benign and malignant lesions can be found in this location.

Cystic Lesions

1. Pericardial cysts
• benign
• usually in the right cardiophrenic space
• CT: well defined, smooth-walled cyst filled with simple fluid
• MR: high signal intensity on T2WI
2. Hydatid cyst
• rare
• may be a herniated hepatic hydatid cyst
• CT: uni- or multilocular cyst with peripheral mural calcifications
• MR: mother cyst (the matrix) is usually intermediate signal intensity on T1WI; daughter cysts are high signal intensity on T2WI
3. Thymic tumors with cystic components

Solid Lesions

1. Lymphadenopathy
• > 8mm in short axis diameter is considered pathologic
• lymphoma is most common cause
2. Thymoma

REFERENCES

Pineda V, Andreu J, Caceres J, et al. Lesions of the cardiophrenic space: findings at cross-sectional imaging. Radiographics 2007;27:19-32.

Extracapsular Rupture of Breast Implants

The above images are from a woman who presented with left chest wall pain after a motor vehicle accident. CECT demonstrates bilateral prepectoral breast implants with asymmetry in size, retraction of the left implant, thickening of its capsule and surrounding hematoma. Findings are suspicious for extracapsular rupture.

While most centers use CECT for the initial evaluation of trauma patients, MRI with dedicated breast coil is the most sensitive for detecting implant rupture. Findings on various imaging modalities include:

Mammography: 

• wrinkled contour of implant
• dense, globular masses due to extracapsular silicone

Ultrasound:

• stepladder sign - linear echogenic layers of the collapsed implant shell
• "snowstorm" appearance - increased echogenicity due to extracapsular spread of silicone

MRI:

• T2WI may show extracapsular high signal
• use of water suppressed STIR images will render bright signal for silicone

REFERENCES

Brown SL, Middleton MS, Berg WA, et al. Prevalence of rupture of silicone gel breast implants revealed on MR imaging in a population of women in Birmingham, Alabama. Am J Roentgenol 2000;175:1057-64.

Scaranelo AM, Marques AF, Smialowski EB, et al. Evaluation of the rupture of silicone breast implants by mammography, ultrasonography and magnetic resonance imaging in asymptomatic patients: correlation with surgical findings. Sao Paulo Med J 2004;122(2):41-7.

Pericardial Effusions in HIV Infection

The above image is from a patient with a history of HIV and lymphoma. CECT demonstrates a thickened, enhancing pericardium with a complex pericardial effusion. Bilateral pleural effusions, right greater than left, are also noted. 

Pericardial effusions are the most common cardiovascular complication of HIV infection and usually carry a poor prognosis. The majority of cases are due to an idiopathic cause. Other causes that must be considered in this population are tuberculosis, bacterial infection (S. aureus is the most common), malignancy (lymphoma and Kaposi's sarcoma), viral, and fungal.


REFERENCES
Chen Y, Brennessel D, Walters J, et al. Human immunodeficiency virus-associated pericardial effusion: report of 40 cases and review of the literature. Am Heart J 1999;137(3):516-21.
Restrepo CD, Diethelm L, Lemos JA, et al. Cardiovascular complications of human immunodeficiency virus. Radiographics 2006;26:213-31.
Wang ZJ, Reddy GP, Gotway MB, et al. CT and MR imaging of pericardial disease. Radiographics 2003;23:S167-80.

The Air Crescent Sign

The air crescent sign refers to a radiolucent rim around a soft tissue density and is characteristic of invasive pulmonary aspergillosis (or other angioinvasive fungal infections) in immunocompromised patients. It results when Aspergillus invades the pulmonary vasculature and causes hemorrhage with subsequent infarction of pulmonary tissue. Over time, the infarcted tissue retracts and is absorbed along its periphery by leukocytes which is what gives rise to the air crescent appearance. The visualization of the air crescent sign indicates a favorable outcome because patients without leukocyte function cannot form this consolidation.

The image above is from a patient with prior history of tuberculosis who presented with a cough. The air crescent sign is seen in the left upper lobe.


REFERENCES
Abramson S. The air crescent sign. Radiology 2001;18:230-2.

Pulmonary Pseudotumors

Nodular Pulmonary Amyloid (Amyloidoma)

• one of the three presentations of amyloidosis in the chest (the other two are tracheobronchial and nodular septal)
• solitary or multiple nodules with smooth contours
• lower lobe, subpleural/peripheral location 
• may calcify or undergo osseous metaplasia
• larger nodules may cavitate or become hemorrhagic
• resection is diagnostic and curative
• differential - primary or metastatic neoplasms

Exogenous Lipoid Pneumonia

• caused by aspiration of mineral, vegetable, or animal oil present in food, radiologic contrast media, or oil based medications
• NECT will show low attenuation, mass-like consolidation, with regions of fat density
• crazy paving

REFERENCES

Gimenez A, Franquet T, Prats R, et al. Unusual primary lung tumors: a radiologic-pathologic overview. Radiographics 2002;22:601-19.

Pulmonary Patterns in Stage IV Sarcoidosis

The Siltzbach classification system defines five stages of sarcoidosis based on chest radiograph findings:
Stage 0 - No radiographic abnormality
Stage 1 - Lymphadenopathy
Stage 2 - Lymphadenopathy + pulmonary infiltrate
Stage 3 - Pulmonary infiltrate
Stage 4 - Pulmonary fibrosis

About 20% of patients with sarcoidosis will develop pulmonary fibrosis which indicates irreversible disease. Three main HRCT patterns of pulmonary fibrosis have been identified and linked to performance on pulmonary function tests:
1. Bronchial distortion in a primarily central distribution, associated with lower expiratory flow rates
2. Honeycombing in a peripheral and upper lobe distribution, associated with restriction and decreased diffusion capacity of carbon monoxide
3. Coarse, irregular linear opacities that radiate from the hila, associated with the least functional impairment.

Distinguishing between these patterns is important as it may predict treatment response to corticosteroids.

REFERENCES
Abhesera M, Valeyre D, Grenier P, et al. Sarcoidosis with pulmonary fibrosis: CT pattern and correlation with pulmonary function. AJR Am J Roentgenol 2000;174(6):1751-1757.
Criado E, Sanchez M, Ramirez J, et al. Pulmonary sarcoidosis: typical and atypical manifestations at high resolution CT with pathologic correlation. Radiographics 2010;30:1567-1586.

Mercury Emoblism to the Lung

Nonthrombotic pulmonary emboli are rare and the imaging findings are specific to the origin of the embolus. Types of nonthrombotic emboli include septic emboli, fat emboli, amniotic fluid emboli, and air emboli. Iodinated oil emboli have been reported after transcatheter chemoembolization of hepatocellular carcinoma. Substances such as talc used in preparation of amphetamines by drug addicts can also embolize to the pulmonary arterial tree.

The above image is from a patient who attempted suicide via intravenous mercury injection. The xray image shows multiple metallic spherules throughout both lungs which is the typical imaging appearance for mercury emboli.


REFERENCES
Han D, Lee KS, Franquet T, et al. Thrombotic and nonthrombotic pulmonary arterial embolism: spectrum of imaging findings. Radiographics. 2003 November;23:1521-39.
Rossi SE, Goodman PC, Franquet T. Nonthrombotic pulmonary emboli. AJR Am J Roentgenol 2000;174:1499-1508.

Idiopathic Dilatation of the Pulmonary Artery

Aneurysms of the main pulmonary artery are rare. About half are attributed to congenital heart disease and are usually associated with pulmonary hypertension. Acquired causes include infection (syphilis, tuberculosis, bacterial endocarditis), vasculitis (Behcet's and Hughes-Stovin syndromes), connective tissue abnormalities (Ehlers Danlos, Marfan's, cystic medial necrosis), and trauma (including malpositioned Swan-Ganz catheters causing iatrogenic pulmonary artery pseudoaneurysm). The aforementioned causes need to be excluded before idiopathic dilatation of the pulmonary artery is considered.

CECT parameters for a normal pulmonary artery are:

1. transverse diameter of main pulmonary artery < 28-29 mm, measured at the bifurcation, perpendicular to the long axis of the artery,
2. main pulmonary artery with a smaller diameter than the adjacent aorta,
3. transverse diameter of right interlobar artery < 16 mm.

Focal dilatation of the pulmonary artery exceeds these parameters. In addition to a dilated main pulmonary artery, CECT may also show enlargement of the right and left pulmonary arteries.


REFERENCES

Nair KKS and Cobanoglu AM. Idiopathic main pulmonary artery aneurysm. Ann Thorac Surg 2001;71:1688-90.
Nguyen ET, Silva CIS, Seely JM, et al. Pulmonary artery aneurysms and pseudoaneurysms in adults: findings at CT and radiography. AJR Am J Roentgenol 2007;188:W126-W134.
Ring NJ and Marshall AJ. Idiopathic dilatation of the pulmonary artery. Brit J Radiol 2002;75:532-5.