Effect of steroids on iopamidol blood-brain transfer constant and plasma volume in brain tumors measured with X-ray computed tomography

Abstract

Tumor blood-brain transfer constant of iopamidol (K) and plasma volume (Vp) were measured in 10 patients with primary brain tumors before and after 7 days of dexamethasone treatment (4 x 4 mg per oral per day) using X-ray computed tomography. Both K and Vp decreased significantly after dexamethasone treatment with p < 0.01 and 0.09 respectively according to one-tail paired t-test. The mean percentage decrease in K and Vp was 32% and 10% respectively. Functional images of the two parameters before and after treatment were generated and showed clearly the effect of steroids on the reduction of K in brain tumors. In contrast, when before and after treatment contrast enhanced CT scans were compared, no difference was observed in the enhancement in 8 out of 10 cases. The result obtained support the conclusion that: (1) corticosteroids reduce the blood-brain permeability to small hydrophilic molecules; (2) the X-ray computed tomography method we have developed can be used to measure the K and Vp response of brain tumors to steroid therapy; and, (3) ordinary contrast enhanced CT scans at one fixed time or multiple times after contrast injection are not sensitive in detecting the reduction of K due to steroids.

Dynamic Contrast-enhanced CT of Intracranial Meningioma: Comparison of Distributed and Compartmental Tracer Kinetic Models—Initial Results

“…The F values of 19.93 mL Ϯ 7.25 and 19.95 mL Ϯ 7.23 per 100 g⅐min, which we obtained for normal white matter by using the DP and ATH models, respectively, are in good agreement with the value of 22.9 mL per 100 g ⅐ min, reported by Nabavi et al (35). For gray matter, the F values of 29.71 mL Ϯ 9.65 and 29.69 mL Ϯ 9.64 per 100 g ⅐ min, estimated by using the DP and ATH models, respectively, are lower than the value reported by Nabavi (26), and 14.3 mL Ϯ 10.9 per 100 g ⅐ min, reported by Andersen and Jensen (13) for an analysis performed with the CC model in data sets obtained with dynamic MR imaging with gadopentetate dimeglumine in six patients.…”

Current status and guidelines for the assessment of tumour vascular support with dynamic contrast-enhanced computed tomography

“…1) [10]. These trials date back to 1994 and have not only included drugs that target the tumour vasculature but also drugs with other therapeutic mechanisms (Table 3) [38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53][54][55][56]. In some cases, the results from DCE-CT have assisted the "go-no go" decision concerning further drug development, and/or helped to determine a dose to take forward to later development phases.…”

Corticosteroids in brain cancer patients: benefits and pitfalls

“…Interestingly, and despite its common use, there have only been a few prospective clinical trials to determine the optimal dose of dexamethasone in brain cancer patients [10–12]. The efficacy of steroids in reducing the tumor-associated edema has been well demonstrated [13–15]. Approximately 70% of patients with cerebral metastases symptomatically improve after starting steroids.…”

“…The efficacy of steroids in reducing the edema associated with tumors is well confirmed [13–15]. More than 70% of patients with cerebral metastases symptomatically improve after starting steroids.…”