Diagnostic imaging in the management of patients with possible cerebral venous thrombosis: a cost-effectiveness analysis

Cost-effectiveness of diagnostic strategies for venous thromboembolism: a systematic review

Guideline developers consider cost-effectiveness evidence in decision making to determine value for money. This consideration in the guideline development process can be informed either by formal and dedicated economic evaluations or by systematic reviews of existing studies. To inform the American Society of Hematology guideline on the diagnosis of venous thromboembolism (VTE), we conducted a systematic review focused on the cost-effectiveness of diagnostic strategies for VTE within the guideline scope. We systematically searched Medline (Ovid), Embase (Ovid), National Health Service Economic Evaluation Database, and the Cost-effectiveness Analysis Registry; summarized; and critically appraised the economic evidence on diagnostic strategies for VTE. We identified 49 studies that met our inclusion criteria, with 26 on pulmonary embolism (PE) and 24 on deep vein thrombosis (DVT). For the diagnosis of PE, strategies including d-dimer to exclude PE were cost-effective compared with strategies without d-dimer testing. The cost-effectiveness of computed tomography pulmonary angiogram (CTPA) in relation to ventilation-perfusion (V/Q) scan was inconclusive. CTPA or V/Q scan following ultrasound or d-dimer results could be cost-effective or even cost saving. For DVT, studies supporting strategies with d-dimer and/or ultrasound were cost-effective, supporting the recommendation that for patients at low (unlikely) VTE risk, using d-dimer as the initial test reduces the need for diagnostic imaging. Our systematic review informed the American Society of Hematology guideline recommendations about d-dimer, V/Q scan and CTPA for PE diagnosis, and d-dimer and ultrasound for DVT diagnosis.

Associations Between Doppler Internal Jugular Vein Blood Flow and Transverse Sinus Stasis Detected by Magnetic Resonance Imaging

OBJECTIVES

This study aimed to compare the estimated internal jugular vein (IJV) volume flow with Doppler ultrasound in patients with slow flow in the transverse sinuses and normal transverse sinuses on brain magnetic resonance imaging (MRI).

METHODS

Eighty patients between the ages of 18 and 80 years who did not have any signs of sinus vein thrombosis on brain MRI were included. On MRI, cases with hyperintensity due to a signal void loss in the transverse sinuses in coronal fluid attenuation inversion recovery sequences were included in the slow-flow group. The presence of sinus thrombosis was excluded with other MRI pulse sequences and clinical findings. The participants were divided into 2 groups as having normal and slow flow according to MRI findings. Then bilateral IJV volume flow measurements were made by Doppler ultrasound. Bilateral volume flow was estimated by time-averaged blood flow velocities sampled in the center of the IJV, and IJV cross-sectional areas were measured. We defined the dominant IJV as the one having the higher estimated volume flow of the 2 sides.

RESULTS

Total estimated IJV blood flow was lower (P < .001) in patients with slow flow on MRI (546 mL/min) compared to those without (768 mL/min). A similar finding was seen for the nondominant IJV. In a receiver operating characteristic analysis, the cutoff value for the total estimated IJV volume flow was determined to be 590 mL/min, and the cutoff value for nondominant estimated IJV volume flow was determined to be 202 mL/min to distinguish between the groups.

CONCLUSIONS

Low estimated volume blood flow in the IJV is associated with MRI evidence of stasis in the ipsilateral transverse sinus.

Cost-Effectiveness of Advanced Neuroimaging for Transient and Minor Neurological Events in the Emergency Department

Background Accurate diagnosis of patients with transient or minor neurological events can be challenging. Recent studies suggest that advanced neuroimaging can improve diagnostic accuracy in low-risk patients with transient or minor neurological symptoms, but a cost-effective emergency department diagnostic evaluation strategy remains uncertain. Methods and Results We constructed a decision-analytic model to evaluate 2 diagnostic evaluation strategies for patients with low-risk transient or minor neurological symptoms: (1) obtain advanced neuroimaging (magnetic resonance imaging brain and magnetic resonance angiography head and neck) on every patient or (2) current emergency department standard-of-care clinical evaluation with basic neuroimaging. Main probability variables were: proportion of patients with true ischemic events, strategy specificity and sensitivity, and recurrent stroke rate. Direct healthcare costs were included. We calculated incremental cost-effectiveness ratios, conducted sensitivity analyses, and evaluated various diagnostic test parameters primarily using a 1-year time horizon. Cost-effectiveness standards would be met if the incremental cost-effectiveness ratio was less than willingness to pay. We defined willingness to pay as $100 000 US dollars per quality-adjusted life year. Our primary and sensitivity analyses found that the advanced neuroimaging strategy was more cost-effective than emergency department standard of care. The incremental effectiveness of the advanced neuroimaging strategy was slightly less than the standard-of-care strategy, but the standard-of-care strategy was more costly. Potentially superior diagnostic approaches to the modeled advanced neuroimaging strategy would have to be >92% specific, >70% sensitive, and cost less than or equal to standard-of-care strategy's cost. Conclusions Obtaining advanced neuroimaging on emergency department patient with low-risk transient or minor neurological symptoms was the more cost-effective strategy in our model.

The Venous Occlusion Image Score: A Novel Quantitative Scoring Instrument for Cerebral Venous Sinus Thrombosis

PURPOSE

This study aims to test the validity of a new quantitative scoring instrument-the Venous Occlusion Image Score (VOIS), and assess the diagnostic and prognostic value of VOIS for cerebral venous sinus thrombosis (CVST).

METHODS

The VOIS divided the major cerebral venous sinuses and internal jugular veins into nine parts of interest. CT venography and DSA source images and reconstruction were extracted from the database, then interpreted and scored independently according to VOIS by a panel of three reviewers. Inter-observer and intra-observer reliability were determined using the intraclass correlation coefficient (ICC) and the kappa coefficient (κ). The primary outcome was the 3-month functional outcome and evaluated by modified Rankin Scale (mRS). The sensitivity and specificity of VOIS for the primary outcomes were computed. Logistic regression was applied to evaluate the association between the score on VOIS and the primary outcomes.

RESULTS

Fifty-six patients with CVST were included in the study. For 16 patients underwent cerebral CTV and DSA, excellent interobserver agreement was observed for DSA (ICC=0.90, 95%CI = 0.87 - 0.92, P < 0.001), and CTV (ICC = 0.92, 95%CI = 0.84 - 0.93, P < 0.001). The κ coefficient of agreement for the two radiology measures was 0.88 (95%CI = 0.79-0.92), indicating good inter-method agreement. For 56 patients followed up by CTV, baseline VOIS value correlated inversely with the severity of stroke on the National Institutes of Health Stroke Scale (r = -0·53, P < 0·001), and modified Rankin Scale (r = -0·59, P < 0·001). Baseline CTV-VOIS value predicted functional outcome (P < 0·05).

CONCLUSION

VOIS may serve as a convenient and reliable method in the treatment guidance and outcome prediction of patients with CVST.

Cerebral Venous Thrombosis: Review of Diagnosis, Follow-Up, Late Complications and Potential Pitfalls

Cerebral venous thrombosis is a less common but relevant cause of stroke in adults. The clinical manifestations are nonspecific leading frequently diagnostic delays, so imaging findings are is of vital importance. Conventional imaging modalities, namely computed tomography and magnetic resonance imaging (MRI), allow identification of the thrombus and parenchymal involvement due to venous congestion to a variable degree, but this entity may appears as a nonexpected finding in a nonvenographic study. computed tomography and MRI venographies allow noninvasive confirmation of the diagnosis and adequate characterization of the extent of the thrombus and acute complications, both of them being robust diagnostic techniques. MR venography also can be done without the use of contrast media, which is especially important in certain clinical situations. Cerebral venous thrombosis needs follow-up, and imaging plays a key role in detection of late complications of the disease, including dural arteriovenous fistulas and intracranial hypertension due to veno-occlusive disease. Knowledge of other diseases and conditions that may mimic a thrombus is needed to avoid wrong diagnosis. In this article, we conduct a pictorial comprehensive review of cerebral venous thrombosis, including also the technical aspects of different imaging modalities, diagnosis and acute complications, follow-up, late complications and potential imaging mimics.