Scintigraphic Appearances in Patients With Pulmonary Infection and Lung Scintigrams of Intermediate or Low Probability for Pulmonary Embolism

Ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) is the scintigraphic technique of choice for the diagnosis of pulmonary embolism and many other disorders that affect lung function. Data from recent ventilation studies show that the theoretic advantages of Technegas over radiolabeled liquid aerosols are not restricted to the presence of obstructive lung disease. Radiolabeled macroaggregated human albumin is the imaging agent of choice for perfusion scintigraphy. An optimal combination of nuclide activities and acquisition times for ventilation and perfusion, collimators, and imaging matrix yields an adequate V/Q SPECT study in approximately 20 minutes of imaging time. The recommended protocol based on the patient remaining in an unchanged position during the initial ventilation study and the perfusion study allows presentation of matching ventilation and perfusion slices in all projections as well as in rotating volume images based upon maximum intensity projections. Probabilistic interpretation of V/Q SPECT should be replaced by a holistic interpretation strategy on the basis of all relevant information about the patient and all ventilation/perfusion patterns. PE is diagnosed when there is more than one subsegment showing a V/Q mismatch representing an anatomic lung unit. Apart from pulmonary embolism, other pathologies should be identified and reported, for example, obstructive disease, heart failure, and pneumonia. Pitfalls exist both with respect to imaging technique and scan interpretation. Semin Nucl Med 40: [415][416][417][418][419][420][421][422][423][424][425]

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“…7). 79,80 V/Q SPECT allows diagnosis of PE and pneumonia when combined in a patient with COPD ( Fig. 8).…”

Section: Pneumoniamentioning

confidence: 99%

Methodology for Ventilation/Perfusion SPECT

Bajc

Neilly

Miniati

et al. 2010

Seminars in Nuclear Medicine

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“…As the ventilation defect often exceeds the perfusion defect, reverse mismatch is a common finding (Carvalho & Lavender, 1989). In a study by Li et al (1994) reverse mismatch represented pneumonia in 81% of the cases. In severe cases both ventilation and perfusion are reduced or abolished and matched defects are then frequently found (Li et al, 1994).…”

Section: Pneumoniamentioning

confidence: 95%

“…In a study by Li et al (1994) reverse mismatch represented pneumonia in 81% of the cases. In severe cases both ventilation and perfusion are reduced or abolished and matched defects are then frequently found (Li et al, 1994). Another sign of pneumonia that often has been described is the "stripe sign" (Sostman & Gottschalk, 1982.…”

Section: Pneumoniamentioning

confidence: 95%

Quantitative Ventilation/Perfusion Tomography: the Foremost Technique for Pulmonary Embolism Diagnosis

Bajc¹,

Jögi²

2012

Pulmonary Embolism

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“…A typical finding is a ventilation defect in an area usually with better preserved perfusion, known as reverse mismatch [21,22]. One of the typical patterns, which strongly support the diagnosis of pneumonia, is the ''stripe sign''.…”

Section: Pneumoniamentioning

confidence: 99%

Potential of hybrid V/P SPECT–low-dose CT in lung diagnostics

Bajc

2012

breathe

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Ventilation/perfusion single photon emission computed tomography (V/P SPECT), is the scintigraphic technique of choice for the diagnosis of pulmonary embolism (PE) and other conditions that affect lung function. In the study of ventilation, hydrophobic radioaerosol Technegas shows advantages over radiolabelled liquid aerosols because of its more even distribution and better peripheral penetration; this is very important in patients with COPD. Macro-aggregated human albumin is the imaging agent for perfusion scintigraphy. V/P SPECT is recommended as a one-day protocol and the whole study is conducted in 20 minutes under a gamma camera. An optimal combination of nuclide activities for ventilation and perfusion, general purpose collimators and a 64664 imaging matrix yields an adequate sensitivity and ensures that radiation doses are kept very low. It is important that the patient remains in an unchanged supine position to allow reconstructed images of matching ventilation and perfusion slices in all projections as well as in rotating volume images. Probabilistic interpretation applied earlier for planar technique is replaced by a holistic interpretation strategy. This has resulted in a decrease in the number of nondiagnostic findings to less than 3%. To reduce costs and radiation exposure, pre-imaging assessment of clinical probability is recommended. PE is diagnosed when there is more than one subsegment showing a ventilation/perfusion mismatch conforming to an anatomic vascular lung unit. Apart from PE, other pathologies should be identified and reported, e.g. COPD, heart failure and pneumonia. Comparison of V/P SPECT with multidetector CT (MDCT) showed higher sensitivity for V/P SPECT, similar specificity and a similar number of nondiagnostic findings. The advantage of V/P SPECT is a 25-times lower absorbed radiation dose to the female breast and its applicability to all patients. The advantage of MDCT is its wider availability. Hybrid SPECT/CT imaging is a novel technique primarily developed to improve sensitivity and specificity of oncological diseases and it is not recommended as the primary tool for PE diagnosis in all patients with suspected PE. The application of SPECT/CT may be relevant in the case of COPD patients where small tumours may be identified as part of the diagnosis; in addition, it may help in the classification of COPD degree. Statement of interestNone declared.HERMES syllabus link: module D. 3.1

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Scintigraphic Appearances in Patients With Pulmonary Infection and Lung Scintigrams of Intermediate or Low Probability for Pulmonary Embolism

Cited by 25 publications

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Methodology for Ventilation/Perfusion SPECT

Methodology for Ventilation/Perfusion SPECT

Quantitative Ventilation/Perfusion Tomography: the Foremost Technique for Pulmonary Embolism Diagnosis

Potential of hybrid V/P SPECT–low-dose CT in lung diagnostics

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