None listed
Conditions
Brief summary
Pulmonary emboli (PE) are common and overlooking the diagnosis can result in serious harm and death. Various imaging modalities including ventilation-perfusion (V/Q) scanning and Computed Tomography Pulmonary Angiography (CTPA) are used. These imaging tests are imperfect and, even when combined with pretest stratification, often leave the clinician uncertain as to the presence or absence of PE. Initial studies have suggested that Single Photon Emission Computed Tomography (SPECT) V/Q scintigraphy may be more sensitive and specific than planar V/Q scintigraphy, and have higher intra-observer reproducibility and fewer non-diagnostic studies. Studies also suggest that SPECT V/Q scintigraphy may be safer than CTPA for patients with contrast allergy and for young or pregnant women.
Interventions
All patients to receive the following: One planar ventilation/perfusion (V/Q) scintigraphy using Technegas and 185MBq (5mCi) Tc-99m-Macro Aggregated Albumin (MAA) (Pulmolite CIS-US Inc Bedford MA USA) acquired on dual head Picker Prism 2000 (Cleveland Ohio) or Siemens eCam (Knoxville Tennessee) gamma cameras using low energy high-resolution collimators on the Tc-99m photopeak of 140kEv +/-10% for 60 stops 15 (10) seconds/stop 360 degrees; one SPECT ventilation/perfusion (V/Q) scintigraphy using
All patients to receive the following: One planar ventilation/perfusion (V/Q) scintigraphy using Technegas and 185MBq (5mCi) Tc-99m-Macro Aggregated Albumin (MAA) (Pulmolite CIS-US Inc Bedford MA USA) acquired on dual head Picker Prism 2000 (Cleveland Ohio) or Siemens eCam (Knoxville Tennessee) gamma cameras using low energy high-resolution collimators on the Tc-99m photopeak of 140kEv +/-10% for 60 stops 15 (10) seconds/stop 360 degrees; one SPECT ventilation/perfusion (V/Q) scintigraphy using Technegas and 185MBq (5mCi) Tc-99m-Macro Aggregated Albumin (MAA) (Pulmolite CIS-US Inc Bedford MA USA) acquired on dual head Picker Prism 2000 (Cleveland Ohio) or Siemens eCam (Knoxville Tennessee) gamma cameras using low energy high-resolution collimators on the Tc-99m photopeak of 140kEv +/-10% for 60 stops 15 (10) seconds/stop 360 degrees; one 16-row multidetector computed tomography pulmonary angiography (CTPA) extended from 1 cm above the aortic arch to the diaphragm, using contrast (120ml of Iomeron 300) injected intravenously at a rate of 3.5 ml/sec, and Philips MX8000 IDT model (Philips Healthcare Andover MA USA) or Toshiba Aquilion 16 model (Toshiba Minato-ku Tokyo, Japan) scanners operating with 16 times 0.75 mm collimation at pitch 0.9 and 0.5 second rotation and time and exposure factors of 120 kVp and 230 mA. with dose modulation software and automated bolus tracking software; Xray; d-dimer; respiratory physicians' diagnosis based on clinical measures and observations, Xray, CTPA, XDPVTE (d-dimer) and 3 month follow up. The information provided for the physicians' diagnosis specifically excludes the planar and SPECT ventilation/perfusion images and reports. Planar and SPECT ventilation and perfusion scintigraphy and CTPA are to be performed within 24 hours of each other, with the first scan commencing as soon as possible after recruitment, and the order of tests determined by the treating clinician. The scheduling and number of other diagnostic tests is also determined by the treating clinician, according to his/her clinical management plan. The physicians' diagnosis is separate from the treating clinician's diagnosis, and is reached at least three months after the completion of scans, and after retrospective review of the clinical information, CTPA scan report and three-month follow-up.
Sponsors
Professor Michael Hensley
Study design
Allocation
Non-randomised trial
Primary purpose
Diagnosis
Eligibility
Sex/Gender
All
Age
50 Years to No maximum
Healthy volunteers
No
Inclusion criteria
Under investigation for presumed acute pulmonary embolism (PE), glomerular filtration rate above the lowest quartile for age group, ability to give informed consent, willingness to undergo all scans, screening completed before the scheduled time of first scan
Exclusion criteria
Critical illness Current haemodynamic instability with shock or hypotension Sustained ventricular tachycardia or ventricular fibrillation in the previous 24 hours Myocardial infarction in the previous month, with ongoing instability Chronic pulmonary hypertension Renal impairment or on dialysis Mechanical ventilatory support Pregnancy Allergy to intravenous contrast or iodine or lung scan agents Severe thyroid disease Previous pulmonary emboli Inferior vena caval filter Likelihood of receiving thrombolysis within 24 hours Evidence of an alternative source of thromboemboli other than the pelvic veins and lower extremities Institutionalised patient or prisoner Likelihood of discharge before completion of study scans
Outcome results
None listed