Coexisting intrarenal arteriovenous and caliceovenous fistulae after percutaneous nephrolithotomy: Case report and literature review.

A 58-year-old man was re-admitted to the Urology service with delayed gross hematuria and unstable he-modynamics, following a percutaneous nephrolithotomy (PCNL) procedure performed for an obstructive solitary left lower calyceal stone. A selective left renal angiogram demonstrated an interpolar arteriovenous fistula (AVF), which was treated with successful coil embolization of a sub-segmental feeding branch. Sub-sequent nephrostogram confirmed a coexisting caliceovenous fistula, which was observed and healed spon-taneously. Iatrogenic coexisting intrarenal AVF and caliceovenous fistulae have never been reported and should be considered as a possible cause of delayed severe hematuria with unstable hemodynamics, and/or increase in baseline creatinine after PCNL.

Modality-specific occult intrarenal pseudoaneurysm in a renal allograft and the legacy of catheter angiography.

A 69-year-old man with history of end-stage-renal disease (ESRD) underwent successful kidney transplantation from a cadaveric donor in November 2011. However, posttransplant recovery was complicated by delayed graft function and recurrent gross hematuria. Serial Doppler ultrasound (US) of the renal allograft demonstrated a pseudoaneurysm with interval increase in size. However, it could not be visualized with other modalities, including an initial angiogram (postoperative day 49) and a second angiogram (postoperative day 68), followed by surgical exploration (postoperative day 71), which demonstrated complete intra-aneurysmal thrombosis on intraoperative Doppler US. Unfortunately, the patient's hematuria continued and a repeat Doppler US 48 hours later demonstrated a persistent pseudoaneurysm. Therefore, on postoperative day 75, we performed targeted percutaneous intra-aneurysmal thrombin injection under dual image guidance, which showed complete intra-aneurysmal thrombosis on intraprocedural Doppler US. Hematuria recurred the next day. A third angiogram (postoperative day 77) finally illuminated the hidden pseudoaneurysm occult on the first and second angiographic studies (sensitivity [index case] 33%) and surgery. This allowed for successful coil embolization of a subsegmental feeding branch with an excellent outcome. We support a more aggressive management with serial angiography and embolization of the intrarenal symptomatic pseudoaneurysm rather than surgery in renal allograft recipients, with the benefits outweighing the risks.

Human breast cancer tumor models: molecular imaging of drug susceptibility and dosing during HER2/neu-targeted therapy.

PURPOSE: To use near-infrared (NIR) optical imaging to assess the therapeutic susceptibility and drug dosing of orthotopic human breast cancers implanted in mice treated with molecularly targeted therapy. MATERIALS AND METHODS: This study was approved by the institutional animal care and use committee. Imaging probes were synthesized by conjugating the human epidermal growth factor receptor type 2 (HER2)-specific antibody trastuzumab with fluorescent dyes. In vitro probe binding was assessed with flow cytometry. HER2-normal and HER2-overexpressing human breast cancer cells were orthotopically implanted in nude mice. Intravital laser scanning fluorescence microscopy was used to evaluate the in vivo association of the probe with the tumor cells. Mice bearing 3-5-mm-diameter tumors were intravenously injected with 0.4 nmol of HER2 probe before or after treatment. A total of 123 mice were used for all in vivo tumor growth and imaging experiments. Tumor fluorescence intensity was assessed, and standard fluorescence values were determined. Statistical significance was determined by performing standard analysis of variance across the imaging cohorts. RESULTS: HER2 probe enabled differentiation between HER2-normal and HER2-overexpressing human breast cancer cells in vitro and in vivo, with binding levels correlating with tumor trastuzumab susceptibility. Serial imaging before and during trastuzumab therapy revealed a significant reduction (P < .05) in probe binding with treatment and thus provided early evidence of successful HER2 inhibition days before the overall reduction in tumor growth was apparent. CONCLUSION: NIR imaging with HER2-specific imaging probes enables evaluation of the therapeutic susceptibility of human mammary tumors and of drug dosing during HER2-targeted therapy with trastuzumab. This approach, combined with tomographic imaging techniques, has potential in the clinical setting for determining patient eligibility for and adequate drug dosing in molecularly targeted cancer therapies.

Targeted nanoparticles for imaging incipient pancreatic ductal adenocarcinoma.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) carries an extremely poor prognosis, typically presenting with metastasis at the time of diagnosis and exhibiting profound resistance to existing therapies. The development of molecular markers and imaging probes for incipient PDAC would enable earlier detection and guide the development of interventive therapies. Here we sought to identify novel molecular markers and to test their potential as targeted imaging agents. METHODS AND FINDINGS: Here, a phage display approach was used in a mouse model of PDAC to screen for peptides that specifically bind to cell surface antigens on PDAC cells. These screens yielded a motif that distinguishes PDAC cells from normal pancreatic duct cells in vitro, which, upon proteomics analysis, identified plectin-1 as a novel biomarker of PDAC. To assess their utility for in vivo imaging, the plectin-1 targeted peptides (PTP) were conjugated to magnetofluorescent nanoparticles. In conjunction with intravital confocal microscopy and MRI, these nanoparticles enabled detection of small PDAC and precursor lesions in engineered mouse models. CONCLUSIONS: Our approach exploited a well-defined model of PDAC, enabling rapid identification and validation of PTP. The developed specific imaging probe, along with the discovery of plectin-1 as a novel biomarker, may have clinical utility in the diagnosis and management of PDAC in humans.

Comparison of angiographic CT and spiral CT to assess cement distribution after vertebral augmentation.

PURPOSE: To compare angiographic computed tomographic (CT) imaging with standard spiral CT imaging for the depiction of extraosseous cement after vertebral augmentation. MATERIALS AND METHODS: Retrospective analysis of 28 consecutive patients treated with vertebral augmentation for compression fracture was conducted. Intraprocedural angiographic CT and postprocedural spiral CT images were acquired in all patients. Angiographic CT and spiral CT images were evaluated independently by two experienced radiologists. RESULTS: All vertebral augmentation procedures were performed successfully. All observed cement leaks were small, and no patient underwent additional treatment for cement leak. One level was excluded as a result of severe motion artifacts that rendered angiographic CT nondiagnostic. Further analysis was performed in the remaining 27 patients (12 men; mean age, 62 years; age range, 31-87 y) corresponding to 48 vertebral levels. Seventeen patients were treated under general anesthesia (33 levels) and 11 were treated under conscious sedation (15 levels). To detect the presence of extraosseous cement, angiographic CT achieved sensitivity of 0.70 and 0.57 for reader 1 and reader 2, respectively, and specificity of 0.93 and 0.92, respectively. Stratified analyses by anesthesia type showed sensitivity of 0.73 and 0.50, respectively, for conscious sedation versus 0.67 and 0.62, respectively, for general anesthesia. Specificity was 1.00 and 1.00, respectively, versus 0.92 and 0.90, respectively. CONCLUSIONS: Cement leaks were detected with a high specificity and a moderate sensitivity with angiographic CT. No difference was found between treatments with general anesthesia versus intravenous conscious sedation.

Colonic adenocarcinomas: near-infrared microcatheter imaging of smart probes for early detection--study in mice.

PURPOSE: To prospectively evaluate the ability of micro-fiberoptic catheters, which simultaneously record white light and near-infrared (NIR) images, to reveal colonic neoplasms after the intravenous administration of activatable "smart" probes that increase in NIR fluorescence subsequent to protease activation. MATERIALS AND METHODS: The institutional animal care committee approved all animal experiments. CT26 tumor cells were orthotopically implanted into the descending colon of C57BL6/J mice (n=10). Thirteen days later, mice intravenously received either 2 nmol of a protease-sensing probe that had cathepsin B as a major activator (n=5) or saline (control animals [n=5]). One day later, animals were noninvasively examined to the point of the splenic flexure by using microcatheter imaging. Excised colons were subsequently evaluated with epifluorescence imaging, histologic examination, and cathepsin B immunohistochemistry. Student t test was used for statistical analysis, with P<.05 considered to indicate a significant difference. RESULTS: Results with fiberoptic imaging demonstrated that all tumors were visible with the protease-activatable probe, even when they were not readily apparent at white light imaging. A target-to-background ratio (TBR) of 8.86 for tumor to adjacent normal mucosa was achieved in the NIR channel after probe administration (P=.001), whereas white light images resulted in a TBR of 1.14 (P>.5) based on luminosity. The tumoral NIR fluorescence intensity was more than 30-fold greater in probe-injected animals than in control animals, indicating that essentially all of the signal recorded in lesions was from activatable probe administration. Results of immunohistochemistry confirmed cathepsin B overexpression in the tumor compared with adjacent mucosa. CONCLUSION: The use of NIR imaging microcatheters combined with protease-activatable smart probes results in a beacon effect that highlights tumors with high TBRs; this technique thus may be a potentially useful adjunct to white light colonoscopy in the future.

Tomographic fluorescence imaging of tumor vascular volume in mice.

PURPOSE: To prospectively determine the feasibility of imaging vascular volume fraction (VVF) and its therapeutic inhibition in mouse models of cancer with three-dimensional fluorescence molecular tomography (FMT). MATERIALS AND METHODS: All studies were approved by the institutional animal review committee and were in accordance with National Institutes of Health guidelines. CT26 colon tumor-bearing mice were imaged with FMT after intravenous administration of long-circulating near-infrared fluorescent blood-pool agents optimized for two nonoverlapping excitation wavelengths (680 and 750 nm). A total of 58 mice were used for imaging VVF to evaluate the following: (a) differences in ectopically and orthotopically implanted tumors (n = 10), (b) cohorts of mice (n = 24) treated with anti-vascular endothelial growth factor (VEGF) antibody, (c) serial imaging in same animal to determine natural course of angiogenesis (n = 4), and (d) dose response to anti-VEGF therapy (n = 20). To compare groups receiving antiangiogenic chemotherapy, analysis of variance was used. RESULTS: Fluorochrome concentrations derived from FMT measurements were reconstructed with an accuracy of +/-10% at 680 nm and +/-7% at 750 nm and in a depth-independent manner, unlike at reflectance imaging. FMT measurements of vascular fluorescent probes were linear, with concentration over several orders of magnitude (r > 0.98). VVFs of colonic tumors, which varied considerably among animals (3.5% +/- 1.5 [standard deviation]), could be depicted with in vivo imaging in three dimensions with less than 5 minutes of imaging and less than 3 minutes of analysis. The natural course of angiogenesis and its inhibition could be reliably imaged and depicted serially in different experimental setups. CONCLUSION: FMT is a tomographic optical imaging technique that, in conjunction with appropriate fluorescent probes, allows quantitative visualization of biologic processes.

Use of molecular imaging to quantify response to IKK-2 inhibitor treatment in murine arthritis.

OBJECTIVE: The NF-kappaB signaling pathway promotes the immune response in rheumatoid arthritis (RA) and in rodent models of RA. NF-kappaB activity is regulated by the IKK-2 kinase during inflammatory responses. To elucidate how IKK-2 inhibition suppresses disease development, we used a combination of in vivo imaging, transcription profiling, and histopathology technologies to study mice with antibody-induced arthritis. METHODS: ML120B, a potent, small molecule inhibitor of IKK-2, was administered to arthritic animals, and disease activity was monitored. NF-kappaB activity in diseased joints was quantified by in vivo imaging. Quantitative reverse transcriptase-polymerase chain reaction was used to evaluate gene expression in joints. Protease-activated near-infrared fluorescence (NIRF) in vivo imaging was applied to assess the amounts of active proteases in the joints. RESULTS: Oral administration of ML120B suppressed both clinical and histopathologic manifestations of disease. In vivo imaging demonstrated that NF-kappaB activity in inflamed arthritic paws was inhibited by ML120B, resulting in significant suppression of multiple genes in the NF-kappaB pathway, i.e., KC, epithelial neutrophil-activating peptide 78, JE, intercellular adhesion molecule 1, CD3, CD68, tumor necrosis factor alpha, interleukin-1beta, interleukin-6, inducible nitric oxide synthase, cyclooxygenase 2, matrix metalloproteinase 3, cathepsin B, and cathepsin K. NIRF in vivo imaging demonstrated that ML120B treatment dramatically reduced the amount of active proteases in the joints. CONCLUSION: Our data demonstrate that IKK-2 inhibition in the murine model of antibody-induced arthritis suppresses both inflammation and joint destruction. In addition, this study highlights how gene expression profiling can facilitate the identification of surrogate biomarkers of disease activity and treatment response in an experimental model of arthritis.

Simultaneous fluorescence imaging of protease expression and vascularity during murine colonoscopy for colonic lesion characterization.

BACKGROUND: Molecularly targeted fluorescent probes are currently being developed to improve the endoscopic detection of intestinal pathologic conditions. OBJECTIVE: We report on the development and testing of a novel multichannel microendoscope capable of quantitatively reporting such probes simultaneously at different wavelengths in real time. We assessed the feasibility of detecting and quantifying beacons that can be activated by protease and correlating imaging with disease state. DESIGN: The microendoscope consisted of a 20-gauge fiberoptic catheter and dichroic beam splitters that simultaneously display visible light, 700 nm and 800 nm near infrared (NIR) fluorescent light. NIR interchannel separation was tested on in vitro phantoms. Two mouse models were used (Apcmin(+/-) mice for colonic adenomas and CT26 murine colon cancer). A perfusion probe and one activated by protease at a separate wavelength were injected before endoscopic evaluation. RESULTS: The microendoscope fluorochrome detection limit was approximately 10 fmol; ratio imaging in the NIR was accurate (+/-8% of true probe concentration between 0.3 to 100 microg/ml of a protease sensor). Both colonic adenomas and adenocarcinomas were clearly visible in the NIR channel on protease probe administration in live mice. Ratio imaging of protease activity/perfusion increased from healthy colon to adenomas to adenocarcinomas. LIMITATIONS: Evaluation across additional spontaneous tumor models may provide more data on the translation of these findings. CONCLUSIONS: Our data show the feasibility of multichannel microendoscopic imaging of molecular targets in vivo and that ratio imaging may provide a novel means for characterizing colonic lesions. When scaled up clinically, this could aid in increasing lesion detection and quantitative assessment of distinct molecular markers.

Translumbar type II endoleak repair using angiographic CT.

Translumbar embolization of type II endoleaks after endovascular abdominal aneurysm repair has been proved to be effective. One challenge of this approach is the choice of the most suitable image guiding modality. For needle placement, cross-sectional imaging under computed tomographic (CT) guidance is preferable. For embolization, fluoroscopy is the modality of choice for most interventionalists. A new technology can acquire CT-like images by rotating an angiographic, flat-panel detector of a C-arm around the patient. This technology allows a combination of fluoroscopic and CT guidance within the angiographic suite. The authors describe the successful use of a combination of fluoroscopy and angiographic CT in three cases of translumbar type II endoleak embolization.

Particularities of the vasculature can promote the organ specificity of autoimmune attack.

How certain autoimmune diseases target specific organs remains obscure. In the 'K/BxN' arthritis model, autoantibodies to a ubiquitous antigen elicit joint-restricted pathology. Here we have used intravital imaging to demonstrate that transfer of arthritogenic antibodies caused macromolecular vasopermeability localized to sites destined to develop arthritis, augmenting its severity. Vasopermeability depended on mast cells, neutrophils and FcgammaRIII but not complement, tumor necrosis factor or interleukin 1. Unexpectedly, radioresistant FcRgamma-expressing cells in an organ distant from the joint were required. Histamine and serotonin were critical, and systemic administration of these vasoactive amines recapitulated the joint localization of immune complex-triggered vasopermeability. We propose that regionally distinct vascular properties 'interface' with immune effector pathways to foster organ-specific autoimmune damage, perhaps explaining why arthritis accompanies many human infectious and autoimmune disorders.

Near infrared thoracoscopy of tumoral protease activity for improved detection of peripheral lung cancer.

Improvement in tumor detection using "smart" probes in combination with microcatheter fluorescence thoracoscopy was evaluated in a mouse model. These imaging probes increase in fluorescence intensity after protease activation; cathepsin B is a major activator of the probes used in this study. Lewis lung carcinoma cells were orthotopically implanted in the subpleural lung parenchyma. Two activatable near infrared (NIR) probes with different excitation and emission wavelength were administered intravenously to determine whether wavelength would modulate target to background ratio (TBR). Mice were selectively intubated and thoracoscopy performed. A 0.8 mm outer diameter imaging catheter was used to record simultaneous white-light (anatomic) and NIR (protease expression) images. At both wavelength pairs evaluated (680/700 and 750/780 nm excitation/emission), the intrinsic luminosity differences between tumors and normal lung in uninjected animals was low (p > 0.3 and p = 0.4, respectively and TBR near 1). In mice receiving protease probes IV, tumors were significantly more fluorescent than adjacent lung (p < 0.0005 for 680/700 and p < 0.006 for 750/780) and TBR increased to approximately 9-fold. Confirmatory fluorescence microscopy and immunohistochemistry were similar and revealed that normal lung had very low levels when compared to tumors of cathepsin B and probe fluorescence. In conclusion, protease sensitive imaging probes selective for cathepsin B, imaged with NIR microcatheters, significantly increase the TBR, making small peripheral lung tumors more readily apparent. Such an approach may be a useful adjunct in staging or restaging patients with lung cancer to find minimal disease in the pleural and subpleural space.

Novel multiwavelength microscopic scanner for mouse imaging.

Real-time in vivo imaging of molecular targets at (sub)cellular resolution is essential in better understanding complex biology. Confocal microscopy and multiphoton microscopy have been used in the past to achieve this goal, but their true capabilities have often been limited by bulky optics and difficult experimental set-ups requiring exteriorized organs. We describe here the development and validation of a unique near-infrared laser scanning microscope system that uses novel optics with a millimeter footprint. Optimized for use in the far red and near-infrared ranges, the system allows an imaging depth that extends up to 500 microm from a 1.3-mm-diameter stick objective, which is up to 2 cm in length. We show exceptionally high spatial, temporal, and multiwavelength resolutions of the system and show that it can be applied to virtually any internal organ through a keyhole surgical access. We demonstrate that, when combined with novel far red imaging probes, it is possible to image the cellular details of many organs and disease processes. The new optics, coupled with the use of near-infrared probes, should prove immensely valuable for in vivo cancer imaging.

A novel mouse model for segmental orthotopic colon cancer.

Spontaneous colon tumor mouse strains offer numerous advantages in modeling disease. However, the wide temporal window in which lesions form and the stochastic nature of lesion location require larger cohorts for assessment of disease modulation. Reliable, reproducible and inexpensive mouse models of early-stage and invasive cancer would add to existing transgenic models. We show a new method for the creation of orthotopic murine tumors centered in the mucosal and submucosal layers anywhere in the colon, allowing creation of lesions of known age, location and extent. The system overcomes the disadvantages of heterotopic implantation and allows evaluation of lesions distally in the colon as well as proximally, thereby providing an additional method to study the effects of regionality. Invasion, host vascularization and application to disparate cell lines are demonstrated. Noninvasive imaging with magnetic resonance and colonoscopy, allowed in part by the tumor location, show potential applications of this approach.

Detection of invasive colon cancer using a novel, targeted, library-derived fluorescent peptide.

Sensitive methods to detect the earliest forms of colorectal cancers remain a challenge despite the development of serum and stool biomarkers. We reasoned that fluorescent affinity ligands derived from library screens can be developed to improve the detection and localization of early malignant lesions by endoscopy. We have developed an imaging agent for real-time endoscopic tumor detection in a murine model using a previously identified phage library-derived colon cancer-specific cyclic peptide and fluorescent moieties. The modified peptide had a 24 minute blood half life and tumoral accumulation was 6.9% of injected dose/g, approximately 7-fold higher than a scrambled control peptide. Orthotopic colonic tumors (HT29) were readily detectable by fluorescence endoscopy even when tumors were submucosal. These results show proof-of-principle that disease-specific library-derived fluorescent probes can be rapidly developed for use in the early detection of cancers by optical means.

Miniaturized multichannel near infrared endoscope for mouse imaging.

We describe the design and construction of a miniaturized multichannel near infrared (NIR) endoscopic imaging system developed for high-resolution imaging of mice. The device allows for simultaneous real-time video images in white light and two independent NIR channels. Testing demonstrated independent acquisition of nanomolar concentrations of fluorochromes Cy5.5 and Cy7. Cross-talk between the NIR channels, partially a result of broad tails in the spectra of commonly used organic fluorochromes, was assessed, modeled for the linear range of the concentration/signal intensity function, and compensated. The calculated compensation was 5.5% and 22% of the total signal intensity in the two channels NIR700 and NIR780, respectively, at equal concentrations of the two fluorochromes. Using a mouse model of colonic adenomatosis, we show that both perfusion and protease activity can be detected simultaneously, independently, and repeatedly in live mice. The developed device should be useful for in vivo imaging of diverse molecular targets.