Effect of phase cycling and averaging on ex vivo prostate image quality.

<p>Cropped and enlarged sections of axial scans: A: 2 PC, 4 NEX, B: 4 PC, 2 NEX, C: 8 PC, 1 NEX. Black arrowheads indicate prostate, white arrowheads urethra, FP is the fat pad used for CNR measurements and LN are the inguinal lymph nodes. Scale bar is 1 cm. Axial scan, FOV 4×4 cm, 200 µm isotropic resolution, TR/TE = 3.9/2.0 ms, FA 30°, BW ±62.5 kHz, 20 minutes.</p

Effect of flip angle and bandwidth on prostate visibility and artifacts.

<p>Flip angle of A: 30° vs B: 40° vs C: 50° at BW of ±62.5 kHz. Bandwidth of D: ±31.25 kHz vs E: ±62.5 kHz vs F: ±83.3 kHz. Red arrowheads indicate prostate boundaries. White arrows point to fat pad used for CNR calculations (FP) and to inguial lymph nodes (ILN). Scale bar is 1 cm. Scan parameters: Axial scan, FOV 3×3 cm, 200 µm isotropic resolution, TR/TE = 3.3–4.6 ms/1.1–2.3 ms, 4 PC, 2 NEX, 14 minutes.</p

Sections of coronal view of mouse with prostate and lymph nodes identified.

<p>Tail is at left, head at right. White arrows indicate organs of interest as follows. A: popliteal lymph nodes; B: prostate; C: iliac lymph nodes; D: inguinal lymph nodes with lymph vessels visible; E: Renal lymph nodes. Scale bar is 0.5 cm. Coronal scan, FOV 6×3.3 cm, 200 µm isotropic resolution, TR/TE = 4.6/2.3 ms, BW ±62.5 kHz, FA 40°, 8 PC, 2 NEX, 26 minutes.</p

Comparison of in vivo axial views acquired with A: bSSFP, B: T1wSE and C: T2wSW.

<p>Black arrows indicate prostate, white arrows indicate urethra. Scale bar is 1 cm. bSSFP images acquired using optimized sequence with 3×3 cm FOV. Spin echo sequences acquired with axial orientation, FOV 3×3 cm, TR/TE = 600/25 ms (T1w), 2000/70 ms (T2w), 1 mm slice thickness, 128×128 matrix, 234 mm in-plane resolution, and 20 (T1w) and 17 (T2w) minutes acquisition time.</p

3 views of prostate from one in-vivo scan.

<p>A: axial, B: coronal, C: sagittal. White arrows indicate prostate. Scale bar is 0.5 cm. Axial scan, FOV 3×3 cm, 200 µm isotropic resolution, TR/TE = 4.6 ms/2.3 ms, 4 PC, 2 NEX, FA 50°, BW ±62.5 kHz, 14 minutes.</p

Representative endpoint MRI, fluorescence microscopy, and immunohistochemistry acquired at 10x magnification from both implant models.

<p>(A) By day 16, 5/7 immune competent mice had no ¹⁹F signal remaining as shown by the representative MRI. The reference tube is marked by “R”. (B) Fluorescence microscopy of the muscle tissue revealed little red fluorescence remaining in the immune competent mice. No GFP+ mMSC were detectable by fluorescence microscopy, suggesting the original mMSC are no longer present. (C) H&E staining reveals the presence of cells at the implant site which correlate well with the remaining ¹⁹F red fluorescence. (D) Immunohistochemistry staining of adjacent tissue sections with the anti-F4/80 antibody reveals the presence of a few macrophages at this location in the immune competent model. (E) At endpoint, all immune compromised mice had detectable ¹⁹F-MRI signal remaining. (F) We observed more red fluorescence from the ¹⁹F-label at the transplant site in the immune compromised mice. (G) Once again, H&E staining in the immune compromised model correlates well with the regions of red fluorescence. (H) Macrophage staining of the immune compromised model reveals many more F4/80 positive cells at the site of implantation. Furthermore, the fluorescence microscopy of neighboring tissue sections reveals that the red fluorescence from the ¹⁹F agent is in the same location as the macrophages. Once again, scale bars represent 250μm.</p

H&E sections of brachial lymph nodes from C57B/l6, Nude and C.B.-17 SCID mice.

<p>Whole nodes are shown at 5x magnification. The T cell rich paracortex (arrowsheads) and B cell rich follicles (arrows) can be easily seen in the nodes of C57B/l6 mice, where as in Nude mouse lymph nodes, only the B cell rich follicles can be seen (arrows). In the areas of the paracortex where T cells should be found, vacant areas are detected (arrowheads), helping to explain the hyperintense appearance of many of these nodes in MR images. Nodes in SCID mice lack both the paracortex and follicles, leaving these nodes underdeveloped and significantly smaller in size.</p

<i>In vitro</i> validation of ¹⁹F-MRI quantification accuracy.

<p>Quantification was validated in a phantom study using cell pellets ranging from 2x10⁵ to 2x10⁶ MSC. Pellets were imaged three times, with the error bars representing the standard deviation between scans. The ¹⁹F-MRI quantification is in very strong agreement with the true number of cells, and has a Pearson correlation coefficient of 0.99. The red line represents the ideal result of a 1:1 correlation.</p

MR images of a nude mouse brachial lymph node acquired with different pulse sequences.

<p>(A) bSSFP image of whole mouse body, (B) bSSFP image of lymph node, (C) T1w SE of lymph node (TR = 600 ms, TE = 25 ms), (D) T2w SE of lymph node (TR = 2000 ms, TE = 80 ms)</p

Cellular viability and loading with the ¹⁹F-agent.

<p>(A) Cellular viability was investigated before and after labeling with the ¹⁹F-agent, Cell Sense. Although a statistically significant difference was observed in hMSC after labeling, the viability remained high (>80%) in all experiments. There was no significant difference in mMSC viability. (B) Cellular loading was determined by performing NMR on a known number of cells alongside a reference peak with a known number of ¹⁹F atoms. We observed variation in cellular loading of both hMSC and mMSC between experiments. However, this variation does not affect in vivo ¹⁹F quantification since each transplant was only compared to its specific cellular loading.</p