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8 - The Role of Imaging in the Follow-up of SARS
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- By GE Antonio, KT Wong, DSC Hui, AT Ahuja
- Edited by A. T. Ahuja, The Chinese University of Hong Kong, C. G. C. Ooi, The Chinese University of Hong Kong
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- Book:
- Imaging in SARS
- Published online:
- 27 October 2009
- Print publication:
- 24 June 2004, pp 79-88
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Summary
Introduction
Severe acute respiratory syndrome (SARS) has shown itself to be different from most other forms of viral pneumonia in its infectivity, clinical course, predilection for affecting health care workers, and high rates of mortality and morbidity. During the acute phase of the epidemic the imaging characteristics of SARS during the acute phase been investigated, but its post-treatment sequelae are only just becoming apparent as they surface in the imaging of patients attending follow-up. In line with the acute stages of this disease, the recovery also appears to be punctuated with an exaggeration of the host response, with patients developing residual disease or early signs of fibrosis in affected areas of the lungs. With this in mind, the follow-up of these patients will require close clinical and radiological monitoring. This chapter shall present the appearances and role of imaging in the follow-up of SARS.
Follow-up presentation of SARS patients
Follow-up is usually uneventful for most other types of viral pneumonia in adults. However, while a portion of treated and discharged SARS patients may be completely asymptomatic, a significant number have residual symptoms. It has been reported that 46% of discharged patients complained of exertional dyspnoea at 1-month follow-up. This was not restricted to elderly patients but also affected patients in their 30s, resulting in the limitation of their daily activities.
6 - Chest Radiography: Clinical Correlation and Its Role in the Management of Severe Acute Respiratory Syndrome
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- By DSC Hui, KT Wong, GE Antonio, AT Ahuja, JJY Sung
- Edited by A. T. Ahuja, The Chinese University of Hong Kong, C. G. C. Ooi, The Chinese University of Hong Kong
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- Book:
- Imaging in SARS
- Published online:
- 27 October 2009
- Print publication:
- 24 June 2004, pp 61-68
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Summary
Introduction
Chest radiography (CXR) not only plays an important role in the diagnosis of severe acute respiratory syndrome (SARS), it is crucial in the management of these patients. During treatment there are variable clinical and radiological responses in different patients and serial CXR help in deciding whether escalation to more aggressive treatment is necessary.
Based on our preliminary experience, we believe that changes on serial radiographs is also an important prognostic indicator.
This chapter aims to examine the correlation between the clinical course and the radiological features, and the role of CXR in the management of SARS.
Treatment protocol
The treatment of SARS patients is discussed in detail in a separate chapter (see Chapter 9). However, in order to better understand the clinical and radiological correlation one must be familiar with the basic treatment principles. These are therefore discussed briefly in the following paragraph.
Patients were treated for the first 2 days with broad-spectrum antibiotics for community-acquired pneumonia according to the American Thoracic Society Guidelines. Our initial treatment consisted of intravenous (IV) cefotaxime 1 g every 6 hours and oral clarithromycin 500 mg twice daily (or oral levofloxacin 500 mg daily for those who could not tolerate clarithromycin).
Clinical symptoms, arterial blood oxygen saturation and CXR were assessed daily.
7 - The Role of High-Resolution Computed Tomography in Diagnosis of SARS
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- By GE Antonio, KT Wong, DSC Hui, AT Ahuja
- Edited by A. T. Ahuja, The Chinese University of Hong Kong, C. G. C. Ooi, The Chinese University of Hong Kong
-
- Book:
- Imaging in SARS
- Published online:
- 27 October 2009
- Print publication:
- 24 June 2004, pp 69-78
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Summary
Introduction
Plain radiography and high-resolution computed tomography (HRCT) are the cornerstones for imaging the lungs. HRCT is capable of imaging the lungs with excellent spatial resolution, providing anatomical detail similar to that available from gross pathological specimens or lung slices. It is especially good for the early detection and characterization of localized or diffused lung parenchymal abnormalities. However HRCT involves a high-radiation dose, is not readily available and therefore may not be suitable as the first line of investigation for suspected severe acute respiratory syndrome (SARS) patients or in a screening role in endemic/pandemic situation. In such a situation, HRCT should be reserved for selected group of patients with good clinical indication and non-diagnostic chest radiograph (CXR). The indications should be more relaxed with sporadic cases. The diagnostic protocol for imaging and the use of CXR and HRCT have been discussed previously (Figure 7.1).
Apart from diagnosis, HRCT also plays an important role to monitor progress and response to treatment and for follow-up. These will be dealt with separately in later chapters. This chapter aims to give the reader an insight about the role of HRCT in diagnosis of SARS and to describe various radiological appearances on HRCT.
5 - The Role of Chest Radiographs in the Diagnosis of SARS
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- By KT Wong, GE Antonio, EHY Yuen, AT Ahuja
- Edited by A. T. Ahuja, The Chinese University of Hong Kong, C. G. C. Ooi, The Chinese University of Hong Kong
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- Book:
- Imaging in SARS
- Published online:
- 27 October 2009
- Print publication:
- 24 June 2004, pp 53-60
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Summary
Introduction
At the onset of the severe acute respiratory syndrome (SARS) crisis, the majority of patients were presented with respiratory symptoms. As the epidemic progressed, either due to a different mode of transmission or a mutation of the virus, some SARS patients presented with minor or no respiratory symptoms but diarrhoea. Understandably, this created a problem with case definition and diagnosis, and the lack of a reliable and rapid biochemical test for SARS placed more emphasis on chest imaging findings for diagnosis of the disease.
The wide availability, speed and inexpensive nature of the chest radiograph (CXR) has made it the first-line imaging investigation when faced with a respiratory complaint. It is only fitting that the initial imaging investigation of SARS also starts here. This chapter presents the radiographic features of SARS and the differential diagnosis.
Pathological considerations
Viral infection of the respiratory tract may involve the upper system, from the common cold (rhinoviruses and coronaviruses), larynx (respiratory syncitial virus), trachea and bronchi (herpes simplex type 1) to the lung parenchyma (influenza). The initial phase in viral lung parenchymal involvement is called a pneumonitis. A local inflammatory response is directed towards the offending virus, an inflammatory cocktail of cells and fluid accumulate in the alveolar interstitium of the lung parenchyma. In bacterial infections this exudate spills over into the airspace and results in the classic consolidation.