Pulmonary CT Angiography Protocol Adapted to the Hemodynamic Effects of Pregnancy

Ridge, Carole A.; Mhuircheartaigh, Jennifer Ní; Dodd, Jonathan D.; Skehan, Stephen J.

doi:10.2214/ajr.10.5385

Cited by 49 publications

(36 citation statements)

References 20 publications

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“…The difficult clinical picture and heightened concern for pulmonary embolism may explain the lower positivity rate in this population. Additionally, the physiologic changes of pregnancy including the heightened effect of the Valsalva maneuver and increased blood and tidal volumes during pregnancy may lead to decreased pulmonary artery opacification, a potentially serious issue for CTPA [8,[11][12][13]. In this study, we found decreased pulmonary artery opacification in pregnant and postpartum patients, which did not reach statistical significance (P= .12) but that was associated with a significantly higher proportion of CTs interpreted as limited or nondiagnostic (12% vs. 0%).…”

Section: Discussioncontrasting

confidence: 59%

CT pulmonary angiography in pregnant and postpartum women: low yield, high dose

et al. 2015

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Section: Discussioncontrasting

confidence: 59%

CT pulmonary angiography in pregnant and postpartum women: low yield, high dose

et al. 2015

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“…contrast in the pulmonary vessels, necessitating adjustments in triggered scan delays. 14,28 Transient influx of unopacified blood from the inferior vena cava has also been identified as a cause for poor-quality CTPA scans during pregnancy. 3,14 Consequently, the American Thoracic Society/Society of Thoracic Radiology guidelines recommend using CTPA only in females with no signs or symptoms of DVT and an abnormal chest X-ray.…”

Section: Diagnostic Performancementioning

confidence: 99%

“…Revel et al 30 obtained a mean effective dose of 7.3 mSv with a 64-slice CT scanner. Ridge et al 28 were able to decrease the mean effective dose from 5.6 to 4.8 mSv, by using a pregnancyadapted imaging protocol. The use of effective dose for assessing the exposure of patients has severe limitations that must be considered when quantifying medical exposure.…”

Section: Dosimetrymentioning

confidence: 99%

Diagnosing venous thromboembolism in pregnancy

Grüning

Mingo

Gosling

et al. 2016

BJR

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Objective: We report the imaging outcomes of all pregnant patients referred for suspected thromboembolism over a 43-month period. Methods: We identified 168 patients who underwent ventilation/perfusion (VQ) single-photon emission CT (SPECT), CT pulmonary angiography (CTPA) or a Doppler ultrasound scan of the lower legs, as well as a control group of 89 non-pregnant age-and sex-matched patients who underwent VQ SPECT during the same period. Imaging outcomes were recorded, and radiation doses were calculated for individual patients. Results: VQ SPECT and CTPA were equally likely to diagnose pulmonary embolism (PE) in about one patient out of every seven patients investigated. One in three CTPA scans was of suboptimal quality. A Doppler ultrasound examination of the legs will find deep venous thrombosis much less often, in about 1 patient out of every 15 patients investigated. The prevalence of PE in pregnant patients (as diagnosed by VQ SPECT) was similar to that in the non-pregnant, age-and sex-matched control group. The effective dose and the absorbed radiation dose to the maternal breast were lower with VQ SPECT. The foetal dose is comparable for both VQ SPECT and CTPA. Conclusion: VQ SPECT and CTPA provide a similar diagnostic yield for diagnosing PE during pregnancy, but VQ SPECT does so with a lower radiation dose to the mother (effective dose and breast dose). Advances in knowledge: Ours is the first report of the diagnostic performance of VQ SPECT, rather than planar VQ scans, in pregnancy in a routine clinical setting.

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“…Two studies including 105 and 24 pregnant women with suspected PE reported defi nite diagnostic scans in 94 % and 96 % of cases with normal initial chest radiography, respectively [80,82]. Regarding CTPA, the hyperdynamic eff ects of pregnancy, which include increases in cardiac output, vascular resistance, heart rate and plasma volume, can lead to a dilution of contrast agent and possibly to an interruption of the contrast bolus when opacifi ed blood from the superior vena cava is mixed with unopacifi ed blood from the IVC, which can result in poor opacifi cation of the pulmonary arteries [49,80,81,83]. Furthermore, pressure in the IVC is increased by the gravid uterus, especially in the supine position, and there is a signifi cant increase in IVC blood fl ow during deep inhalation.…”

Section: Lung Scintigraphy or Ct Scanmentioning

confidence: 99%

“…Technically inadequate and therefore non-diagnostic CTPA examinations have been reported in 6-36 % of cases [80, 84 -86]. Therefore, CTPA protocols must consider the haemodynamic changes that occur during pregnancy and should be adapted to improve image quality (e.g., avoidance of initial deep inhalation, automated bolus tracking, a short scan delay, high iodine fl ux achieved by high fl ow rate of contrast medium and/or high iodine concentration) [49,83]. In addition, adequate low-dose strategies for both lung scintigraphy and CTPA should be used while maintaining diagnostic quality [49].…”

Section: Lung Scintigraphy or Ct Scanmentioning

confidence: 99%

Diagnosis of pregnancy-associated venous thromboembolism - position paper of the Working Group in Women’s Health of the Society of Thrombosis and Haemostasis (GTH)

Linnemann¹,

Scholz

Rott

et al. 2016

Vasa

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EpidemiologyVTE is a leading cause of maternal morbidity in the developed world and, in the case of PE, of mortality as well [1]. While the relative risk of VTE is greatly increased during pregnancy compared with that in non-pregnant women, the absolute risk remains low: estimates of the incidence of pregnancy-associated VTE have varied from 1:500 to 1:1500 pregnancies [2 -7]. The risk of VTE is approximately 5-fold greater in pregnant women than in non-pregnant women.Approximately 80 % of pregnancy-associated VTEs are isolated DVTs, and approximately 20 % are PEs or both DVTs and PEs [5]. Although a systematic review reported weighted event rates for DVT of 21.9 %, 33.7 % and 47.6 % for the fi rst, second and third trimesters, respectively [6], a recent study suggested that the risk might in fact increase exponentially over the duration of the pregnancy [7], with 12.4 % of VTEs diagnosed in the fi rst trimester, 15.3 % in the second trimester and 72.3 % in the third trimester. This detailed risk assessment for each gestational week demonstrated a 21-fold increased risk for the last two weeks before delivery [7]. Summary: Pregnancy and the postpartum period are associated with an increased risk of venous thromboembolism (VTE). Over the past decade, new diagnostic algorithms have been established, combining clinical probability, laboratory testing and imaging studies for the diagnosis of deep vein thrombosis (DVT) and pulmonary embolism (PE) in the non-pregnant population. However, there is no such generally accepted algorithm for the diagnosis of pregnancy-associated VTE. Studies establishing clinical prediction rules have excluded pregnant women, and prediction scores currently in use have not been prospectively validated in pregnancy or during the postpartum period. D-dimers physiologically increase throughout pregnancy and peak at delivery, so a negative D-dimer test result, based on the reference values of non-pregnant subjects, becomes unlikely in the second and third trimesters. Imaging studies therefore play a major role in confi rming suspected DVT or PE in pregnant women. Major concerns have been raised against radiologic imaging because of foetal radiation exposure, and doubts about the diagnostic value of ultrasound techniques in attempting to exclude isolated iliac vein thrombosis grow stronger as pregnancy progresses. As members of the Working Group in Women's Health of the Society of Thrombosis and Haemostasis (GTH), we summarise evidence from the available literature and aim to establish a more uniform strategy for diagnosing pregnancy-associated VTE. Review Diagnosis of pregnancy-associated

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Pulmonary CT Angiography Protocol Adapted to the Hemodynamic Effects of Pregnancy

Abstract: A pulmonary CTA protocol optimized for pregnancy significantly improved image quality by increasing pulmonary arterial opacification, improving diagnostic adequacy, and decreasing transient interruption of the contrast bolus by unopacified blood from the IVC.

Cited by 49 publications

References 20 publications

CT pulmonary angiography in pregnant and postpartum women: low yield, high dose

CT pulmonary angiography in pregnant and postpartum women: low yield, high dose

Diagnosing venous thromboembolism in pregnancy

Diagnosis of pregnancy-associated venous thromboembolism - position paper of the Working Group in Women’s Health of the Society of Thrombosis and Haemostasis (GTH)

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