Dynamic contrast-enhanced MR imaging pharmacokinetic parameters as predictors of treatment response of brain metastases in patients with lung cancer.

OBJECTIVES: To determine the diagnostic accuracy of pharmacokinetic parameters measured by dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) in predicting the response of brain metastases to antineoplastic therapy in patients with lung cancer. METHODS: Forty-four consecutive patients with lung cancer, harbouring 123 newly diagnosed brain metastases prospectively underwent conventional 3-T MRI at baseline (within 1 month before treatment), during the early (7-10 weeks) and midterm (5-7 months) post-treatment period. An additional DCE MRI sequence was performed during baseline and early post-treatment MRI to evaluate baseline pharmacokinetic parameters (K trans, k ep, v e, v p) and their early variation (∆K trans, ∆k ep, ∆v e, ∆v p). The objective response was judged by the volume variation of each metastasis from baseline to midterm MRI. ROC curve analysis determined the best DCE MRI parameter to predict the objective response. RESULTS: Baseline DCE MRI parameters were not associated with the objective response. Early ∆K trans, ∆v e and ∆v p were significantly associated with the objective response (p = 0.02, p = 0.001 and p = 0.02, respectively). The best predictor of objective response was ∆v e with an area under the curve of 0.93 [95% CI = 0.87, 0.99]. CONCLUSIONS: DCE MRI and early ∆v e may be a useful tool to predict the objective response of brain metastases in patients with lung cancer. KEY POINTS: • DCE MRI could predict the response of brain metastases from lung cancer • ∆v e was the best predictor of response • DCE MRI could be used to individualize patients' follow-up.

Cervical foraminal steroid injections under CT guidance: retrospective study of in situ contrast aspects in a serial of 248 cases.

OBJECTIVES: To describe all the CT findings after in situ contrast injection just before steroid injection and to recognize the abnormal aspects associated with intravascular contamination. MATERIAL AND METHODS: We retrospectively evaluated 248 cervical transforaminal steroid injections done at the university hospital in Dijon, France, in 2008-2012, to treat cervicobrachial neuralgia inadequately improved by optimal medical treatment for at least 3 weeks. Features describing the opacification patterns were recorded. RESULTS: Five main nonvascular opacification patterns were identified: clumps of contrast agent outside the foramen (16 %), a crab claw pattern surrounding the ganglion (13 %), a "French" circumflex accent pattern (15 %), reflux along the needle (7 %), and facet joint capsule opacification (22 %). Concerning the situations requiring a change in needle position, intravenous injection occurred in 26 % of the patients, with a crab claw pattern in half the cases and a clump pattern in half the cases. Intraarteriolar injection was noted in two patients. CONCLUSION: CT after in situ contrast injection ensures proper needle positioning outside the blood vessels before steroid injection. Penetration of the needle tip into a vein is very common, whereas arteriolar puncture is extremely rare.