Optical imaging is a modality that is cost-effective, rapid, easy to use, and can be readily applied to studying disease processes and biology in vivo. For this study, we used a green fluorescent protein (GFP)- and luciferase-expressing mouse tumor model to compare and contrast the quantitative and

Optical imaging is a modality that is cost-effective, rapid, easy to use, and can be readily applied to studying disease processes and biology in vivo. For this study, we used a green fluorescent protein (GFP)- and luciferase-expressing mouse tumor model to compare and contrast the quantitative and qualitative capabilities of a fluorescent reporter gene (GFP) and a bioluminescent reporter gene (luciferase). We describe the relationship between tumor volume, tumor mass, and bioluminescent/fluorescent intensity for both GFP and luciferase. Bioluminescent luciferase imaging was shown to be more sensitive than fluorescent GFP imaging. Luciferase-expressing tumors were detected as early as 1 day after tumor cell inoculation, whereas GFP-expressing tumors were not detected until 7 days later. Both bioluminescent and fluorescent intensity correlated significantly and linearly with tumor volume and tumor weight, as measured by caliper. Compared to bioluminescent imaging, fluorescent imaging does not require the injection of a substrate and may be appropriate for applications where sensitivity is not as critical. Knowing the relative strengths of each imaging modality will be important in guiding the decision to use fluorescence or bioluminescence.

Recently, there has been tremendous interest in developing techniques such as MRI, micro-CT, micro-PET, and SPECT to image function and processes in small animals. These technologies offer deep tissue penetration and high spatial resolution, but compared with noninvasive small animal optical imaging

Recently, there has been tremendous interest in developing techniques such as MRI, micro-CT, micro-PET, and SPECT to image function and processes in small animals. These technologies offer deep tissue penetration and high spatial resolution, but compared with noninvasive small animal optical imaging, these techniques are very costly and time consuming to implement. Optical imaging is cost-effective, rapid, easy to use, and can be readily applied to studying disease processes and biology in vivo. In vivo optical imaging is the result of a coalescence of technologies from chemistry, physics, and biology. The development of highly sensitive light detection systems has allowed biologists to use imaging in studying physiological processes. Over the last few decades, biochemists have also worked to isolate and further develop optical reporters such as GFP, luciferase, and cyanine dyes. This article reviews the common types of fluorescent and bioluminescent optical imaging, the typical system platforms and configurations, and the applications in the investigation of cancer biology.

OBJECTIVE: We describe the effects of tumor necrosis factor alpha (TNFalpha) on tumor microvasculature in a murine colon carcinoma model using serial dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). MATERIAL AND METHODS: Mice with subcutaneous murine colon carcinomas (MC-38) were im

OBJECTIVE: We describe the effects of tumor necrosis factor alpha (TNFalpha) on tumor microvasculature in a murine colon carcinoma model using serial dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI). MATERIAL AND METHODS: Mice with subcutaneous murine colon carcinomas (MC-38) were imaged at 4.7 T after administration of 0.2 mmol/kg gadolinium-DTPA. Both treated and control mice (each group, n = 4), were scanned at baseline and 2, 4, 6, and 96 hours. A 2-compartment pharmacokinetic model generated parameters such as K, kep, and initial area under the gadolinium concentration curve (IAUC). RESULTS: The treatment group revealed significant differences in K at all time points after TNFalpha. kep and IAUC were significantly reduced at 2, 6, and 96 hours. The coefficient of variation in control animals ranged from 0.13 for IAUC to 0.30 for K. Mild histologic changes were observed at 2 to 6 hours, but considerable central necrosis with a vascular tumor rim was seen at 96 hours. CONCLUSION: DCE MRI can be used to detect early effects of TNFalpha. Serial DCE MRI is a promising tool in assessing the early effects of antivascular therapies.

OBJECTIVE: We evaluated the ability of pretreatment MRI and PET/CT to improve outcomes for patients with clinically staged International Federation of Gynecology and Obstetrics (FIGO) IB cervical cancer. MATERIALS AND METHODS: We developed a decision-analytic model to predict outcomes for a hypothet

OBJECTIVE: We evaluated the ability of pretreatment MRI and PET/CT to improve outcomes for patients with clinically staged International Federation of Gynecology and Obstetrics (FIGO) IB cervical cancer. MATERIALS AND METHODS: We developed a decision-analytic model to predict outcomes for a hypothetical patient cohort with FIGO IB cervical cancer who underwent pretreatment MRI, PET/CT, MRI and PET/CT, or no further imaging (direct pursuance of surgery). The model incorporated imaging performance, underlying parametrial extension and lymph node involvement, surgery and chemoradiation treatment options, and survival penalties from incorrect assessment of disease extent. Three outcomes were compared: 5-year overall survival, percentage of patients receiving correct primary therapy, and percentage of patients spared "trimodality therapy" (surgery followed by chemoradiation). Sensitivity analysis was performed to assess the effects of model uncertainty on outcomes. RESULTS: The preferred imaging strategy depended on the outcome studied. Five-year overall survival was comparable across strategies but was highest with the no-imaging strategy (92.37%) and with PET/CT (92.36%) and lowest with MRI (92.30%). Triage to correct primary therapy was highest with PET/CT (89.27%) and lowest with MRI (68.21%). Avoidance of trimodality therapy was highest with combined MRI and PET/CT (95.01%) and lowest with the no-imaging strategy (82.32%). Results were somewhat sensitive to imaging test performance characteristics but stable across most parameter ranges tested. CONCLUSION: Pretreatment imaging of FIGO IB cervical cancer patients can optimize triage to appropriate therapy. Although imaging does not appear to improve survival, PET/CT maximizes patient triage to correct therapy, and combined MRI and PET/CT spares the most patients unnecessary trimodality therapy.

Premenopausal women who present with acute pelvic pain frequently pose a diagnostic dilemma, exhibiting nonspecific signs and symptoms, the most common being nausea, vomiting, and leukocytosis. Diagnostic considerations encompass multiple organ systems, including obstetric, gynecologic, urologic, ga

Premenopausal women who present with acute pelvic pain frequently pose a diagnostic dilemma, exhibiting nonspecific signs and symptoms, the most common being nausea, vomiting, and leukocytosis. Diagnostic considerations encompass multiple organ systems, including obstetric, gynecologic, urologic, gastrointestinal, and vascular etiologies. The selection of imaging modality is determined by the clinically suspected differential diagnosis. Thus, a careful evaluation of such a patient should be performed and diagnostic considerations narrowed before a modality is chosen. Transvaginal and transabdominal pelvic sonography is the modality of choice when an obstetric or gynecologic abnormality is suspected, and computed tomography is more useful when gastrointestinal or genitourinary pathology is more likely. Magnetic resonance imaging, when available in the acute setting, is favored over computed tomography for assessing pregnant patients for nongynecologic etiologies because of the lack of ionizing radiation.