1) This document presents a case study of a 61-year-old female patient with shortness of breath, lung cancer with brain metastasis, and bilateral lower limb swelling. Examinations found irregular heart rhythm and crackles in her lungs. 2) Imaging tests including CXR, ventilation scan, perfusion scan, CT scan showed pulmonary thromboembolism with bilateral deep vein thrombosis and SVC thrombosis. 3) The document then discusses using data from the PIOPED II study to determine the sensitivity and specificity of V/Q scintigraphic tests for diagnosing pulmonary embolism. It finds that for acute PE, V/Q scans have a sensitivity of 77.4% and specificity of 97

1. Int 吳易儒
指導醫師 萬醫師
Case presentation

2. Present Illness #25773451
● 61 y/o female
● Shotness of breath for 1 week
● Lung cancer with brain metastasis
● Cough with sputum, Dyspnea on
exertion
● Bilateral lower limbs swelling
● No chest pain, no cold sweating, no
fever

3. Physical Examination
● T/P/R 36.5/129/22
● BP 101/56
● BW 47 Kg
● Conjunctive: Pale
● Breath sound: Bibasilar crackles
● Heart rhythm: Irregularly irregular

4. Lab data

5. Lab data

6. Lab data

7. EKG 2014/09/18

8. Vascular echo 2014/09/18
● There is some thrombosis over
bilateral fem-popliteal vein, which
causes partial occlusion.
● Duplex scanning of arteries:
● Site Right Left
Femoral vein (V) (V)
Calf vein (V) (V)

9. CXR

10. Ventilation scan

11. Perfusion scan

13. CT

54. Diagnosis
● Pulmonary thromboembolism with
bilateral Deep vein thrombosis
● SVC thrombosis
● Lung ca with left pleural and
Pericardial effusion
● Leukocytosis, etiology unspecified, to
exclude concomitant infection

55. Discussion: Acute
pulmonary embolism
Int吳易儒

57. Purpose
● To use Prospective Investigation of
Pulmonary Embolism Diagnosis(PIOPED) II
data to retrospectively determine
1)sensitivity
2)specificity
of V/Q scintigraphic studies

58. Background
● PIOPED II reported (v.s. PIOPED I)
● CT angiography in PA to diagnose APE:
sensitivity=83%,specificity=96%
● Venous phase CT venography:
sensitivity=90%,specificity=95%
● Wells score helped yield positive/negative
predictive values greater than 90% in 89% of
patients
● V/Q scintigrams make predictive values
higher than 90% in 22% of patients

59. Background
● CT has replaced V/Q scanning since 2001,
while it has limitations:
○ Cost
○ Radiation dose
○ Contraindications: reduced renal function, iodine
allergy
● Use PIOPED II data to determine the
sensitivity and specificity of V/Q scintigraphic
studies

60. Materials and Methods
● Multicenter study
● Two blinded PIOPED II central readers for
○ CT angiography
○ Pulmonary DSA
○ V/Q scanning
● Experienced physicians determine the Wells
scores

61. Patients
(a) a diagnosis recorded at V/Q scanning and
either
(b) a Wells score recorded prospectively and a
diagnosis of PE present or PE absent at CT
angiography or
(c) a diagnosis of PE present or PE absent at
DSA.

62. Statistic Analysis
● Compare PIOPED II V/Q scan with DSA
results
● if DSA not performed or no definitive result:
● Compare V/Q scan with CT angiographic
results which concordant with Wells score
● if + CT result: Wells score 2
● if - CT result: Wells score 6

63. Patients and Readings

65. Patients and Readings

66. Positive predictive value in PIOPED II
Probability Portion %
High 89/102 87.2%
Intermediate 47/152 30.9%
Low 6/89 6.7%
Very low 24/415 5.8%
Normal 2/132 1.3%

67. Categorization of V/Q Scan Central
Readings

69. Exclusion of intermediate and low
probability
Sensitivity of PE present= 77.4% (89/115)
Specificity of PE absent= 97.7% (541/554)
26.5 % (241/910) was nondiagnostic
73.5% (669/910) was high or very low
probability or normal scan

70. Categorization of V/Q Scan Central
Readings
● PE present (high probability) and PE absent
(very low probability or normal) categories
showed for acute PE:
● sensitivity=77.4%
● specificity=97.7%
● V/Q scintigram was categorized as PE
present or PE absent in 73.5% of patients

71. Discussion
● DSA is the most widely accepted imaging
reference standard
● If no DSA result- CT angiography
concorcant with the Wells score due to:
○ CTA and Wells score concordance associated with
high PPV and NPV
○ The sensitivity/ specificity of V/Q scan without DSA
with only CTA and Wells score concordance= 85.1%
/ 98.2%

72. Discussion
● In PIOPED II, fewer patients was low
probabilities or normal, due to:
● Criteria for interpreting V/Q scans have
improved considerably since PIOPED I
● Difference from V/Q scan reading depends
on the patient (population, ex. p’t in ICU)
○ PIOPED I: inpatients and critically ill
○ PIOPED II: outpatients

74. Discussion
● Combine low proobability and very low
probability due to similarity:
○ Sensitivity= 73.6%, Specificity=98.0%
○ Nondiagnostic= 16.7% of population
● Combine Wells score with V/Q categories:
PPV or NPV 90%

75. Comparion of CTA and V/Q scan in
PIOPED II
● More nondiagnostic results with V/Q
scanning (26.5% of p’t) than CT (6.2% of p’t)
● Remove nondiagnostic studies- V/Q and
CTA have similar sensitivity and specificity
(77% and 98%) (83% and 96%)

76. Discussion
DSA was not performed in all patients due to
less use of invasive pulmonary angiography
PIOPED II supported CTA with Wells score as
an alternative diagnostic reference to DSA

77. Conclusion
● V/Q scintigraphy
○ yields diagnostically definitive results
○ an appropriate pulmonary imaging procedure
● in patients for whom CTA may be
disadvantageous

78. Thanks for your attention