Adaptability, sensitivity, resolution and non-invasiveness are the attributes that have contributed to the longstanding use of light as an investigational tool and form the basis of optical imaging (OI). OI, which encompasses numerous techniques and methods, is rapid (<5 min), inexpensive, noninvasive, nontoxic (no radiation) and has molecular (single-cell) sensitivity, which is equal to that of conventional nuclear imaging and several orders of magnitude greater than MRI. This article provides a comprehensive overview of emerging applications of OI-based techniques for in vivo monitoring of new stem cell-based therapies. Different fluorochromes for cell labeling, labeling methods and OI-based cell-tracking techniques will be reviewed with respect to their technical principles, current applications and aims for clinical translation. Advantages and limitations of these new OI-based cell-tracking techniques will be discussed. Non-invasive mapping of cells labeled with fluorochromes or OI marker genes has the potential to evolve further within the clinical realm.

Acute stenting of the cervical ICA in combination with intracranial thrombectomy was technically feasible and safe in our series. Thrombectomy prior to proximal stenting was associated with shorter reperfusion times and a tendency towards better clinical outcome leading to a good outcome in about 50 % of the patients. Therefore, we recommend this approach in tandem occlusion requiring stent angioplasty.

MR imaging of bone marrow infiltration by hematologic malignancies provides non-invasive assays of bone marrow cellularity and vascularity to supplement the information provided by bone marrow biopsies. This article will review the MR imaging findings of bone marrow infiltration by hematologic malignancies with special focus on treatment effects. MR imaging findings of the bone marrow after radiation therapy and chemotherapy will be described. In addition, changes in bone marrow microcirculation and metabolism after anti-angiogenesis treatment will be reviewed. Finally, new specific imaging techniques for the depiction of regulatory events that control blood vessel growth and cell proliferation will be discussed. Future developments are directed to yield comprehensive information about bone marrow structure, function and microenvironment.

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The FR-targeted USPIO P1133 demonstrates a specific retention in FR-positive breast cancers. Because FR expression correlates with tumor aggressiveness and prognosis, persistent P1133 tumor enhancement may be used as a noninvasive indicator for tumors with poor outcome.

With the conversion factors, reliable volumetric BMD measurements can be calculated for the hip and the spine from routine abdominal and pelvic MDCT data sets.

ObjectiveTo record the MR imaging features of primary central nervous system lymphoma (PCNSL) and compare these features in monofocal and multifocal disease.Materials and MethodsTwenty-one cases of monofocal disease were compared to five cases of multifocal disease. All patients were examined by non-enhanced and contrast-enhanced MRI. Tumor location, tumor size, signal intensity, enhancement characteristics, age distribution, peritumoral edema, cystic changes, and the presence of calcifications were assessed. The MRI features were compared between the monofocal and multifocal disease cases.ResultsThe 26 cases, including both the monofocal and multifocal cases, exhibited 37 lesions. Contrast-enhanced images showed variable enhancement patterns: homogeneous enhancement (33 lesions), ring-like enhancement (2), and 'open-ring-like' enhancement (2). The 'notch sign' was noted in four of 33 homogeneously enhancing lesions. One case of hemorrhage and three cases of cystic formation were observed. Intra-tumoral calcification was not found. The frontal lobe, the corpus callosum and the basal ganglia were commonly affected in both the monofocal and multifocal groups. Tumor size differed significantly between the two groups (t = 3.129, p < 0.01) and mildly or moderately enhanced lesions were more frequently found in the monofocal group (p < 0.05). There was no statistical difference between perifocal edema (p > 0.05) and the signal characteristics (p > 0.05) between the two groups.ConclusionOur data show that PCNSL has a variable enhancement pattern on MR images. We first reported two lesions with an 'open-ring' enhancement as well as four cases with a 'notch sign'. Monofocal PCNSL cases typically have larger sized tumors with mild or moderate enhancement.

The purpose of this study was to track fluorophore-labeled, tumor-targeted natural killer (NK) cells to human prostate cancer xenografts with optical imaging (OI). NK-92-scFv(MOC31)-zeta cells targeted to the epithelial cell adhesion molecule (EpCAM) antigen on prostate cancer cells and nontargeted NK-92 parental cells were labeled with the near-infrared dye DiD (1,1'-dioctadecyl-3,3,3',3'-tetramethylindodicarbocyanine). The fluorescence, viability, and cytotoxicity of the labeled cells were evaluated. Subsequently, 12 athymic rats with prostate cancer xenografts underwent OI scans before and up to 24 hours postinjection of DiD-labeled parental NK-92 cells or NK-92-scFv(MOC31)-zeta cells. The tumor fluorescence intensity was measured and compared between pre- and postinjection scans and between both groups using t-tests. OI data were confirmed with fluorescence microscopy. In vitro studies demonstrated a significant increase in the fluorescence of labeled cells compared with unlabeled controls, which persisted over a period of 24 hours without any significant change in the viability. In vivo studies demonstrated a significant increase in tumor fluorescence at 24 hours postinjection of tumor-targeted NK-92-scFv(MOC31)-zeta cells but not parental NK cells. Ex vivo OI scans and fluorescence microscopy confirmed a specific accumulation of NK-92-scFv(MOC31)-zeta cells but not parental NK cells in the tumors. Tumor-targeted NK-92-scFv(MOC31)-zeta cells could be tracked to prostate cancer xenografts with OI.