Published ahead of print on April 8, 2009
doi: 10.3174/ajnr.A1555
Novel Microcatheters for Selective Intra-Arterial Injection of Fluid in the Rat Brain
W.E. Zinka,
C.P. Foleyc,
J.P. Dykea,d,
M.J. Synana,d,
A.L. Chakrapania,
D.J. Ballona,d,
W.L. Olbrichtc and
Y.P. Gobina,b
a Department of Radiology, Weill Medical College of Cornell University, New York, NY
b Department of Neurological Surgery, Weill Medical College of Cornell University, New York, NY
c Department of Chemical and Biomolecular Engineering, Weill Medical College of Cornell University, New York, NY
d Citigroup Biomedical Imaging Core Facility (CBIC), Weill Medical College of Cornell University, New York, NY
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Fig 1. Schematic representation of the rat intracranial ICA and the territories of its proximal branches. A, Intracranial arterial supply in the rat with rostral oriented upward. The ACA, MCA, PCA, HTA, and AchoA are labeled.10 B, Axial representation of the rat forebrain 2 to 4 mm caudal to bregma shows the medial thalamus (MH) and lateral thalamus (LT), the thalamus (Thal), internal capsule (IC), and striatum (St). The vascular territories of the HTAs (gray hatching) and AchoA (filled black) are shown.
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Fig 2. 3D time-of-flight imaging was used to estimate the ICA diameter. Axial images show the origins of the AchoA (A) and MCA (B). Arrowheads show the course of the AchoA. M and A represent the origins of the MCA and ACA. The HTAs are not visualized.
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Fig 3. Rat brain arterial microcatheters. A, The 169-µm OD polyimide microcatheters have 35-µm perforations at 1, 2, 3, and 4 mm proximal to the tip (arrows). Every other pair of perforations is oriented 90° from the previous. The distal tips of both microcatheters are plugged with epoxy. The bottom microcatheter has a 450-µm bulb glued to its distal tip (µcath2). Markings at the top of the image represent millimeters. B, Methylene blue injected through µcath1 demonstrates side port positions.
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Fig 4. Injection of gadolinium into a single cerebral hemisphere demonstrated with ex vivo MR imaging. Thoracotomy was performed and the right atrium sectioned before injection of 300 µL of 1:1 Magnevist:saline for 10 minutes via µcath1. The brain was removed, soaked in formalin for 30 minutes, and imaged with an MPRAGE sequence. Axial images A to F are displayed from rostral to caudal at +1.7, +0.5, –0.9, –1.8, –2.1, and –5.8 mm relative to bregma. Gadolinium-containing vessels were dark because of the concentration effect. Midline vessels (not labeled), irregular vessels seen in long axis within the deep brain, and linear vessels within the cortical mantle are thought to represent veins. Branching vessels arising from the ventral aspect and vessels seen in cross-section are thought to represent arteries (not labeled).
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Fig 5. Single cerebral hemisphere injection during dynamic MR imaging. Axial T1 GE-MR images acquired 4 to 5 mm caudal to bregma at –1 (A) and 5 (B), 11 (C), and 29 (D) s after the beginning of a 10-s hand-injection of Magnevist:NS via µcath1 (ie, from 0–10 s).
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Fig 6. Selective injection of gadolinium into the hypothalamus and lateral thalamus. Axial T1 GE-MR images acquired 4 to 5 mm caudal to bregma at 0 (A), 6 (B), 12 (C), and 30 s (D) after the beginning of a 10-s hand-injection of Magnevist:NS via µcath2.
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Fig 7. Selective injection of 18FDG into the hypothalamus. MicroPET data were acquired 5 minutes after injection of 20 µCi 18FDG in 10-µL NS via µcath2 for 1 minute. Activity is represented by red (270 µCi/mL), yellow (240 µCi/mL), green (195 µCi/mL), and blue (90 µCi/mL). MicroPET images were manually coregistered with 2-mm-thick axial T1-weighted images and coronal and sagittal reformats. Panel A is 1.0 to 0.8 mm rostral to bregma. Panels B through D are 1.0 to 1.2 mm, 3.0 to 3.2 mm, and 5.0 to 5.2 mm caudal to bregma, respectively.
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