Conventional Imaging Tools Research Articles

A novel [89Zr]-anti-PD-1-PET-CT to assess response to PD-1/PD-L1 blockade in lung cancer.

Harnessing the anti-tumor immune system response by targeting the program cell death protein (PD-1) and program cell death ligand protein (PD-L1) axis has been a major breakthrough in non-small cell lung cancer (NSCLC) therapy. Nonetheless, conventional imaging tools cannot accurately assess response in immunotherapy-treated patients. Using a lung cancer syngeneic mouse model responder to immunotherapy, we aimed to demonstrate that [89Zr]-anti-PD-1 immuno-PET is a safe and feasible imaging modality to assess the response to PD-1/PD-L1 blockade in NSCLC. A syngeneic mouse model responder to anti-PD-1 therapy was used. Tumor growth and response to PD-1 blockade were monitored by conventional 2-deoxy-2-[18F]fluoro-D-glucose ([18F]-FDG) PET scans. Additionally, tumor lymphocyte infiltration was analyzed by the use of an [89Zr]-labeled anti-PD-1 antibody and measured as 89Zr tumor uptake. Conventional [18F]-FDG-PET scans failed to detect the antitumor activity exerted by anti-PD-1 therapy. However, [89Zr]-anti-PD-1 uptake was substantially higher in mice that responded to PD-1 blockade. The analysis of tumor-infiltrating immune cell populations and interleukins demonstrated an increased anti-tumor effect elicited by activation of effector immune cells in PD-1-responder mice. Interestingly, a positive correlation between [89Zr]-anti-PD-1 uptake and the proportion of tumor-infiltrating lymphocytes (TILs) was found (Cor = 0.8; p = 0.001). Our data may support the clinical implementation of immuno-PET as a promising novel imaging tool to predict and assess the response of PD-1/PD-L1 inhibitors in patients with NSCLC.

Prognostic value of total tumor volume with 68Ga DOTATOC PET/CT in predicting response to 177-Lu-DOTATOC treatment in metastatic well-differentiated neuroendocrine tumors (NETs).

e16248 Background: PET/CT with somatostatin analogues (68 Ga DOTATOC) is essential for decision-making prior to treatment with [177Lu–Dota0–Tyr3]–Octreotate (177Lu-DOTATOC), there are biological characteristics in this type of neoplasms that allow predicting the response to therapy, the tumor burden is one of the most important variables, however its estimation with conventional imaging tools is limited, currently there are reconstruction algorithms based on artificial intelligence that allow estimating the tumor burden using molecular imaging studies with 68 Ga DOTATOC, aim of this work is to determine the value of the total tumor load with this radiotracer as a predictor of overall survival in patients treated with 177Lu DOTATOC. Methods: 45 patients (11 men and 34 women) with an average age of 57.2 (range 47.2 to 66.5) with histopathological and immunohistochemical diagnosis of well-differentiated neuroendocrine tumors (NETs) in the period from 2015 to 2021 who received therapy with (177Lu-DOTATOC) and who had a baseline 68Ga DOTATOC PET to calculate total tumor volume (TVV) and semiquantitative uptake values were retrospectively included. Results: The mean follow-up was 29.3 +/- 6 months. Using ROC curves, a cut-off point of 100 cm3 was determined to differentiate responding and non-responding patients. The difference in the overall survival curves between both groups was statistically significant (470 days vs. 180 days) with p=0.07. The main sites of origin of the primary tumor were pancreas (n=24), lung (n=11), small intestine (n=7) and liver (n=3). The mean tumor volume was 305.8 cm3 (+/- 272). The organs with the highest uptake values were pancreas with SUVmax of 27.9 (range 10.1-42.4), rectum with SUVmax 26.5 (10.7-42.3) and liver with SUVmax of 22.1 (14.4-31.7), these uptake values did not have any type of relation to patient survival. Regarding therapy with 177 Lu DOTATOC, 8 received 14.8 Gbq (400mCi), 12; 22.2 GBq (600mCi) and 25; 29.6 GBq (800 mCi), no serious adverse effect or kidney function impairment was demonstrated after 177Lu DOTATOC therapy. No grade 3 or 4 haematological toxicity was identified. Conclusions: PET/CT with 68 Ga-DOTATOC is routinely used in the management of patients with neuroendocrine tumors and also allows categorizing patients according to their tumor volume to predict overall survival in patients treated with 177 Lu-DOTATOC, thus in such a way that it could be considered as an easily accessible and widely available prognostic imaging biomarker.

Image‐based response assessment during immunotherapy in skin cancer

Immune-checkpoint inhibitors and further immunotherapeutic treatment strategies have significantly extended therapy options for melanoma and other skin cancer entities over the last decade. In the context of a broader application of immunotherapeutic approaches, sufficient ways to monitor the course of the disease during therapy are required. Immunotherapies are based on different ways of modulating the immune system. This leads to complex clinical response patterns including pseudoprogression and others, requiring an adaptation of conventional diagnostic imaging tools or the introduction of novel technologies. In this review, current non-invasive imaging approaches for response assessment during immunotherapies in skin cancers as well as their limitations are discussed. To overcome present hurdles, promising alternatives to better address novel imaging features during immunotherapy are depicted giving an outlook on what can be expected in the future.

Novel insights about ribosomal DNA double strand break repair revealed by super-resolution imaging techniques and very fast CRISPR.

Ribosomal DNA (rDNA) is repetitive gene sequence that produces the RNA components for the translation machinery in eukaryotic cells - ribosomes. The maintenance of rDNA genome stability against double-strand breaks (DSBs) is critical regarding cellular aging related diseases and tumor development due to its repetitive nature and distribution over multiple chromosomes. Previous studies have shown that DSB within rDNA region will induce rDNA transcriptional repression and nucleolar segregation. However, it remains poorly understood regarding the kinetics of associated transcriptional regulation, the architecture of the nucleolar cap, and the link between them, likely due to the resolution limit of conventional imaging tools and the absence of proper system that can rapidly induce DSBs specific to rDNA region with accurately controlled timing. To resolve these limitations and provide deeper insights on how rDNA DSB repair response is regulated, we use self-built super-resolution fluorescence imaging systems, e.g., stimulated emission depletion microscopy, which allow to visualize nucleolar structures beyond the diffraction limit, and lattice light sheet microscopy, which enables to monitor fast kinetics of the repair process with minimal photo-induced disturbance, combined with a recently developed rapidly-inducible photo-caged CRISPR-Cas9 system (very fast CRISPR, vfCRISPR) in our lab, to study the spatiotemporal coordination of the DSB repair factor assembly upon rDNA DSB damage, and dissect its important role in regulating pathway choice and outcome fidelity.

X-ray computerized microtomography and confocal Raman microscopy as complementary techniques to conventional imaging tools for the microstructural characterization of Cheddar cheese.

This study explored the use of X-ray computerized microtomography (micro-CT) and confocal Raman microscopy to provide complementary information to well-established techniques, such as confocal laser scanning microscopy (CLSM), for the microstructural characterization of cheese. To evaluate the potential of these techniques, 5 commercial Cheddar cheese samples, 3 with different ripening times and 2 with different fat contents, were analyzed. Confocal laser scanning microscopy was particularly useful to describe differences in fat and protein distribution, especially between the 2 samples with different fat contents. The quantitative data obtained through image analysis correlated well with the nutritional information provided in the product labels. Conversely, micro-CT was more advantageous for studying the size and spatial distribution of microcrystals present within the cheese matrix. Two types of microcrystals were identified that differed in size, shape, and X-ray attenuation. The smallest, with a diameter of approximately 10 to 20 μm, were more abundant in the samples and presented a more uniform roundish shape and higher X-ray attenuation. Larger and more heterogeneous crystals with diameters reaching 50 μm were also observed in scarcer numbers and showed lower X-ray attenuation. Confocal Raman microscopy was useful not only for identifying the distribution of all these components but also allowed comparing the presence of micronutrients such as carotenoids in the cheeses and provided compositional information on the crystals detected. Small and large crystals were identified as calcium phosphate and calcium lactate, respectively. Overall, using micro-CT, confocal Raman microscopy, and CLSM in combination generated novel and complementary information for the microstructural and nutritional characterization of Cheddar cheese. These techniques can be used to provide valuable knowledge when studying the effect of milk composition, processing, and maturation on the cheese quality attributes.

Image guidance for FLASH radiotherapy.

FLASH radiotherapy (FLASH-RT) is an emerging ultra-high dose (>40Gy/s) delivery that promises to improve the therapeutic potential by limiting toxicities compared to conventional RT while maintaining similar tumor eradication efficacy. Image guidance is an essential component of modern RT that should be harnessed to meet the special emerging needs of FLASH-RT and its associated high risks in planning and delivering of such ultra-high doses in short period of times. Hence, this contribution will elaborate on the imaging requirements and possible solutions in the entire chain of FLASH-RT treatment, from the planning, through the setup and delivery with online in vivo imaging and dosimetry, up to the assessment of biological mechanisms and treatment response. In patient setup and delivery, higher temporal sampling than in conventional RT should ensure that the short treatment is delivered precisely to the targeted region. Additionally, conventional imaging tools such as cone-beam computed tomography will continue to play an important role in improving patient setup prior to delivery, while techniques based on magnetic resonance imaging or positron emission tomography may be extremely valuable for either linear accelerator (Linac) or particle FLASH therapy, to monitor and track anatomical changes during delivery. In either planning or assessing outcomes, quantitative functional imaging could supplement conventional imaging for more accurate utilization of the biological window of the FLASH effect, selecting for or verifying things such as tissue oxygen and existing or transient hypoxia on the relevant timescales of FLASH-RT delivery. Perhaps most importantly at this time, these tools might help improve the understanding of the biological mechanisms of FLASH-RT response in tumor and normal tissues. The high dose deposition of FLASH provides an opportunity to utilize pulse-to-pulse imaging tools such as Cherenkov or radiation acoustic emission imaging. These could provide individual pulse mapping or assessing the 3D dose delivery superficially or at tissue depth, respectively. In summary, the most promising components of modern RT should be used for safer application of FLASH-RT, and new promising developments could be advanced to cope with its novel demands but also exploit new opportunities in connection with the unique nature of pulsed delivery at unprecedented dose rates, opening a new era of biological image guidance and ultrafast, pulse-based in vivo dosimetry.

Diagnostic performance of deep-learning-based screening methods for diabetic retinopathy in primary care-A meta-analysis.

BackgroundDiabetic retinopathy (DR) affects 10–24% of patients with diabetes mellitus type 1 or 2 in the primary care (PC) sector. As early detection is crucial for treatment, deep learning screening methods in PC setting could potentially aid in an accurate and timely diagnosis.PurposeThe purpose of this meta-analysis was to determine the current state of knowledge regarding deep learning (DL) screening methods for DR in PC.Data sourcesA systematic literature search was conducted using Medline, Web of Science, and Scopus to identify suitable studies.Study selectionSuitable studies were selected by two researchers independently. Studies assessing DL methods and the suitability of these screening systems (diagnostic parameters such as sensitivity and specificity, information on datasets and setting) in PC were selected. Excluded were studies focusing on lesions, applying conventional diagnostic imaging tools, conducted in secondary or tertiary care, and all publication types other than original research studies on human subjects.Data extractionThe following data was extracted from included studies: authors, title, year of publication, objectives, participants, setting, type of intervention/method, reference standard, grading scale, outcome measures, dataset, risk of bias, and performance measures.Data synthesis and conclusionThe summed sensitivity of all included studies was 87% and specificity was 90%. Given a prevalence of DR of 10% in patients with DM Type 2 in PC, the negative predictive value is 98% while the positive predictive value is 49%.LimitationsSelected studies showed a high variation in sample size and quality and quantity of available data.

Label-free detection of brain tumors in a 9L gliosarcoma rat model using stimulated Raman scattering-spectroscopic optical coherence tomography.

.Significance: In neurosurgery, it is essential to differentiate between tumor and healthy brain regions to maximize tumor resection while minimizing damage to vital healthy brain tissue. However, conventional intraoperative imaging tools used to guide neurosurgery are often unable to distinguish tumor margins, particularly in infiltrative tumor regions and low-grade gliomas.Aim: The aim of this work is to assess the feasibility of a label-free molecular imaging tool called stimulated Raman scattering-spectroscopic optical coherence tomography (SRS-SOCT) to differentiate between healthy brain tissue and tumor based on (1) structural biomarkers derived from the decay rate of signals as a function of depth and (2) molecular biomarkers based on relative differences in lipid and protein composition extracted from the SRS signals.Approach: SRS-SOCT combines the molecular sensitivity of SRS (based on vibrational spectroscopy) with the spatial and spectral multiplexing capabilities of SOCT to enable fast, spatially and spectrally resolved molecular imaging. SRS-SOCT is applied to image a 9L gliosarcoma rat tumor model, a well-characterized model that recapitulates human high-grade gliomas, including high proliferative capability, high vascularization, and infiltration at the margin. Structural and biochemical signatures acquired from SRS-SOCT are extracted to identify healthy and tumor tissues.Results: Data show that SRS-SOCT provides light-scattering-based signatures that correlate with the presence of tumors, similar to conventional OCT. Further, nonlinear phase changes from the SRS interaction, as measured with SRS-SOCT, provide an additional measure to clearly separate tumor tissue from healthy brain regions. We also show that the nonlinear phase signals in SRS-SOCT provide a signal-to-noise advantage over the nonlinear amplitude signals for identifying tumors.Conclusions: SRS-SOCT can distinguish both spatial and spectral features that identify tumor regions in the 9L gliosarcoma rat model. This tool provides fast, label-free, nondestructive, and spatially resolved molecular information that, with future development, can potentially assist in identifying tumor margins in neurosurgery.

Caged Cumate Enables Proximity-Dependent Control Over Gene Expression.

Cell-cell interactions underlie diverse physiological processes yet remain challenging to examine with conventional imaging tools. Here we report a novel strategy to illuminate cell proximity using transcriptional activators. We repurposed cumate, a small molecule inducer of gene expression, by caging its key carboxylate group with a nitrile. Nitrilase-expressing activator cells released the cage, liberating cumate for consumption by reporter cells. Reporter cells comprising a cumate-responsive switch expressed a target gene when in close proximity to the activator cells. Overall, this strategy provides a versatile platform to image and potentially manipulate cellular interactions over time.

Confirming pericardial access by using impedance measurements from a micropuncture needle.

Pericardial access is complicated by two difficulties: confirming when the needle tip is in the pericardial space, and avoiding complications during access, such as inadvertently puncturing other organs. Conventional imaging tools are inadequate for addressing these difficulties, as they lack soft-tissue markers that could be used as guidance during access. A system that can both confirm access and avoid inadvertent organ injury is needed. A 21G micropuncture needle was modified to include two small electrodes at the needle tip. With continuous bioimpedance monitoring from the electrodes, the needle was used to access the pericardium in porcine models (n=4). The needle was also visualized in vivo by using an electroanatomical map (n=2). Bioimpedance data from different tissues were analyzed retrospectively. Bioimpedance data collected from the subcutaneous space (992.8 ± 13.1Ω), anterior mediastinum (972.2 ± 14.2Ω), pericardial space (323.2 ± 17.1Ω), mid-myocardium (349.7 ± 87.6Ω), right ventricular cavity (235.0 ± 9.7Ω), lung (1142.0 ± 172.0Ω), liver (575.0 ± 52.6Ω), and blood (177.5 ± 1.9Ω) differed significantly by tissue type (P<.01). Phase data in the frequency domain correlated well with the needle being in the pericardial space. A simple threshold analysis effectively separated lung (threshold=1120.0Ω) and blood (threshold=305.9Ω) tissues from the other tissue types. Continuous bioimpedance monitoring from a modified micropuncture needle during pericardial access can be used to clearly differentiate tissues. Combined with traditional imaging modalities, this system allows for confirming access to the pericardial space while avoiding inadvertent puncture of other organs, creating a safer and more efficient needle-access procedure.

Multifrequency Microwave Imaging for Brain Stroke Detection

Early diagnosis of stroke with timely treatment could reduce adult permanent disability significantly [1]. Conventional medical imaging tools such as X-ray, ultrasound, computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) have been widely used for diagnosis of brain disease. However, each of these methods has some limitations. X-ray imaging produces harmful radiation to the human body and challenging to identify early-stage abnormal tissue due to the relatively small dielectric proprieties contrast between the healthy tissue and abnormal tissue at X-ray frequencies [2]. PET provides useful information about soft tissues, but it is expensive and produces poor resolution. CT and MRI are unsuitable for continuously monitoring strokes due to produce harmful radiations (CT), expensive (MRI), time-consuming and not easy to develop a portable system [3,4]. Therefore, develop a new screening method is urgently needed to improve the effectiveness of disease detection. <br/> Microwave imaging is a relatively new non-invasive and cost-effective method for imaging of breast and brain tissues, which has continuously attracted many researchers’ interests over the past two decades [5,6]. The authors previously developed a holographic microwave imaging (HMI) method for dielectric object detection with a particular focus on brain stroke [7]. This paper investigates the feasibility of multifrequency HMI for brain stroke detection. A numerical system was developed to demonstrate the proposed theory. Various experiments were carried out to evaluate the performance of the proposed method. Results of experiments carried out using multifrequency HMI have been compared with the results obtained by using single frequency HMI. Results showed that multifrequency HMI could detect strokes and provide more accurate results of size and location than the single frequency HMI algorithm.

MRI-guided breast biopsy: a review of technique, indications, and radiological–pathological correlations

Breast magnetic resonance imaging (MRI) is the technique of choice in detection, local staging, and monitoring of breast cancer; however, breast MRI results in the detection of more indeterminate/suspicious lesions that need to be histopathologically proven to guide patient management than any other breast imaging method. If such abnormalities are not detectable in any of the conventional imaging tools (mammography (MMG) or ultrasound) then an MRI-guided biopsy needs to be performed to obtain a diagnosis. Breast MRI-guided biopsy is a time-consuming and complex procedure that requires specific equipment and experienced, well-trained staff. This review article explores and illustrates the indications, the currently available technologies, and the technique of breast MRI-guided biopsy, and explains the importance of careful imaging review and selection of cases. We correlate the radiological-pathological findings and highlight the impact on patient management in a multidisciplinary setting.

The prognostic value of conventional imaging tools to determine how patients with hodgkin lymphoma will respond to treatment

Introduction: This systematic review studies the prognostic value of two conventional imaging tools, sestamibi and gallium scans, for predicting how patients with Hodgkin lymphoma will respond to treatment.Methods: The PubMed database was searched for English-language articles that contained the following search terms: (Hodgkin AND [mibi OR sestamibi OR gallium OR spect] AND response). All articles that were identified during this search were included in the study, regardless of date published. The inclusion criteria were as follows: articles that described studies that were limited to Hodgkin patients and that reported the predictive value of conventional imaging tools. Articles about other types of lymphoma and/or those that focused on the diagnostic and staging accuracy of mibi and gallium scans were excluded.Result: In total, 14 articles were retrieved. Of these, the majority met the inclusion criteria of the systematic review with the exception of two, which were limited to an examination of the reliability of performing sestamibi scans to predict the response to treatment. All remaining 12 articles considered both the sestamibi scans and the gallium scintigraphy.The results of the systematic review indicate that positive gallium scan results can be proposed as a poor prognostic factor that is associated with partial or full recurrence of Hodgkin disease, a reduction in overall survival rate, and progression-free survival compared with patients with a negative scan.Discussion: Both sestamibi and gallium scans revealed high sensitivity and specificity in predicting the response to treatment including complete remission, partial remission, and recurrence of the disease.Conclusion:These imaging tools can appropriately assess how Hodgkin patients will respond to chemotherapy. As such, clinicians can use these tools to devise appropriate treatment strategies.

Synchrotron Radiation Sheds Fresh Light on Plant Research: The Use of Powerful Techniques to Probe Structure and Composition of Plants.

While synchrotron radiation is a powerful tool in material and biomedical sciences, it is still underutilized in plant research. This mini review attempts to introduce the potential of synchrotron-based spectroscopic and imaging methods and their applications to plant sciences. Synchrotron-based Fourier transform infrared spectroscopy, X-ray absorption and fluorescence techniques, and two- and three-dimensional imaging techniques are examined. We also discuss the limitations of synchrotron-based research in plant sciences, specifically the types of plant samples that can be used. Despite limitations, the unique features of synchrotron radiation such as high brightness, polarization and pulse properties offer great advantages over conventional spectroscopic and imaging tools and enable the correlation of the structure and chemical composition of plants with biochemical function. Modern detector technologies and experimental methodologies are thus enabling plant scientists to investigate aspects of plant sciences such as ultrafast kinetics of biochemical reactions, mineral uptake, transport and accumulation, and dynamics of cell wall structure and composition during environmental stress in unprecedented ways using synchrotron beamlines. The potential for the automation of some of these synchrotron technologies and their application to plant phenotyping is also discussed.

Formation evaluation in Dezful embayment of Iran using oil-based-mud imaging techniques

Structural delineation and fracture characterization are two of the main issues for the evaluation of carbonate reservoirs in structurally complex areas. Some of such fields are located in the southwest (Dezful embayment) of Iran. Getting to the Asmari reservoir is not so easy in some cases due to structural complexities where a thick pile of evaporites of Gachsaran Formation overly the reservoir. In such cases structural dip information plays an important role in mapping the structure in the area around the wells. In addition to structural complications, fracture characterization is quite important for Asmari carbonates and in particular for Sarvak carbonates. In most fields of the Dezful embayment, it is not feasible to drill wells with water-based mud, hence getting information on structural dip and fractures is not so easy with conventional borehole imaging tools. A combination of oil-based-mud imaging tools provided a new way of imaging the characteristics of formations drilled with oil-based-mud. Complicated structures were resolved utilizing the dip data gathered with such techniques. Fractures were characterized for their aperture (open or closed), intensity of fracturing, and directional attributes. The information helped to understand reservoir characteristics of tight carbonates of Sarvak formation. In addition to structural details, the OBM imaging provided quantitative Rxo (resistivity of invaded zone) measurement in oil-based-mud environment. It helped to understand invasion profiles, which generally is a function of permeability, in carbonate and sandstone reservoirs of Asmari Formation, and helped reservoir engineers and petrophysicists to understand response of reservoir formation tester (RFT) measurements for formation pressure and reservoir fluid mobility. The paper describes applications of OBM imaging in Asmari and Bangestan reservoirs of Dezful embayment of Iran.

The diagnostic usefulness of FDG-PET/CT in detecting tumor recurrence not evident in whole body I131 scan in differentiated thyroid carcinoma

ObjectivePatients with differentiated thyroid carcinoma (DTC) have generally an encouraging prognosis, however, some patients develop an increasing level of serum thyroglobulin (Tg) without detection of a recurrent tumor using conventional imaging tools such as the iodine-131 whole-body scanning (I131 scan). The objective of our study was to evaluate the clinical significance of [F18]-FDG-PET/CT in detection of tumor recurrence or metastases, in comparison to conventional imaging such as the I131 scan. Patients and methodsBetween January 2013 and June 2013, [18F]-FDG-PET/CT examination was done for 12 DTC patients with elevated thyroglobulin levels and who did not show any pathological lesions when conventional imaging modalities were used. All involved patients had undergone total thyroidectomy, and who had been followed-up by whole body iodine scan [F18]-FDG PET/CT data were evaluated for detecting recurrent DTC lesions in study patients and compared with those of other radiological and/or cytological investigations. ResultsFive of 12 patients (41.6 %) showed pathological [F18]-FDG uptake in the absence of abnormal uptake in whole body iodine scan. Conclusion[F18]-FDG-PET/CT affords a valuable diagnostic method in detection of recurrence or metastasis in patients with DTC who are tumor-free on conventional imaging studies with high Tg levels.

Diagnosis and evaluation of gastric cancer by positron emission tomography.

Gastric cancer is the second leading cause of cancer mortality worldwide. The diagnosis of gastric cancer has been significantly improved with the broad availability of gastrointestinal endoscopy. Effective technologies for accurate staging and quantitative evaluation are still in demand to merit reasonable treatment and better prognosis for the patients presented with advanced disease. Preoperative staging using conventional imaging tools, such as computed tomography (CT) and endoscopic ultrasonography, is inadequate. Positron emission tomography (PET), using (18)F-fluorodeoxyglucose (FDG) as a tracer and integrating CT for anatomic localization, holds a promise to detect unsuspected metastasis and has been extensively used in a variety of malignancies. However, the value of FDG PET/CT in diagnosis and evaluation of gastric cancer is still controversial. This article reviews the current literature in diagnosis, staging, response evaluation, and relapse monitoring of gastric cancer, and discusses the current understanding, improvement, and future prospects in this area.

Increased Metabolic Activity Highlighted by Positron Emission Tomography/Computed Tomography in the Wall of the Dissected Ascending Aorta in a Patient With Horton Disease

Horton disease or giant-cell arteritis (GCA) is a chronic systemic vasculitis involving typically medium and large arteries. Giant-cell arteritis is a panarteritis characterized by a granulomatous inflammation, with lymphocytes, macrophages, and multinucleated giant cells related to autoimmune T-cell reactivity.1 Compared with conventional imaging tools (ultrasound, computed tomography (CT), MRI, and contrast angiography) that provide anatomic and morphological information, recent available imaging techniques such as positron emission tomography (PET)/CT provide metabolic assessment of the arterial wall. During the early 2000s, Sakalihasan et al2 observed a close correlation between clinically unstable abdominal aortic aneurysms and increased uptake of 18F-fluoro-2-deoxy-d-glucose (FDG) in the aneurysmal wall. A few years later, Hautzel et al3 studied the assessment of giant-cell arteritis with PET/CT. We describe a case of Horton disease involving the thoracic aorta and complicated with acute aortic dissection in a woman with a previous diagnosis of thoracic aortic aneurysm. In July 2011, a 66-year-old woman was referred to a cardiology center for evaluation of a recent mild hypertension related to use of high doses of corticosteroids. In December 2010, she had developed severe headache, rapid loss of weight, and elevation of sedimentation rate as high as 120 mm. Horton disease was diagnosed in April 2011 on temporal artery biopsy. During the first cardiologic examination, …

A quantum dot probe conjugated with aβ antibody for molecular imaging of Alzheimer's disease in a mouse model.

The treatment of Alzheimer's disease (AD) has been hampered by a lack of sensitive and specific non-invasive diagnostic methods. Quantum dots (QD) are nano-crystals with unique photo-physical properties that bypass some of the limitations of conventional dyes and imaging tools. This study is aimed to evaluate the fluorescence properties of a QD probe conjugated with an anti-Aβ antibody (QD-Aβ-Ab). Healthy mice and mice bearing mutated human APP695swe and APP717 V-F transgenes received intracerebroventricular injection of the probe for subsequent imaging. Immunohistochemistry revealed that Aβ1-42 was distributed in the hippocampus CA1 area in the APP transgenic mice. Fluorescence microscopy demonstrated that fluorescence was mainly observed in the hippocampus area, the cerebral cortex, sagittal septum and striatum of APP transgenic mice. In vivo imaging of mice receiving the QD-Aβ-Ab probe showed that healthy mice exhibited a narrow range of fluorescence and lower fluorescence intensity compared with APP transgenic mice. The mean fluorescence intensity of brain tissues of healthy C57BL mice was 12.3784 ± 3.9826, which was significantly lower than that of 10- and 16-month-old APP transgenic mice (45.03 ± 2.66 and 46.69 ± 3.22, respectively; P < 0.05). In this study we present the first direct evidence that QD-Aβ-Ab conjugate probes can track in vivo state of Aβ accumulation in mice and the findings suggest that such probes may be of potential use for early molecular diagnostic imaging of AD.

Effectiveness of [124I]-PET/CT and [18F]-FDG-PET/CT for Localizing Recurrence in Patients with Differentiated Thyroid Carcinoma

Although the prognosis of patients with differentiated thyroid carcinoma (DTC) is generally encouraging, a diagnostic dilemma is posed when an increasing level of serum thyroglobulin (Tg) is noted, without detection of a recurrent tumor using conventional imaging tools such as the iodine-131 whole-body scanning (the [131I] scan) or neck ultrasonography (US). The objective of the present study was to evaluate the diagnostic value of [124I]-PET/CT and [18F]-FDG-PET/CT in terms of accurate detection of both iodine- and non-iodine-avid recurrence, compared with that of conventional imaging such as the [131I] scan or neck ultrasonography (US). Between July 2009 and June 2010, we prospectively studied 19 DTC patients with elevated thyroglobulin levels but who do not show pathological lesions when conventional imaging modalities are used. All involved patients had undergone total thyroidectomy and radioiodine (RI) treatment, and who had been followed-up for a mean of 13 months (range, 6-21 months) after the last RI session. Combined [18F]-FDG-PET/CT and [124I]-PET/CT data were evaluated for detecting recurrent DTC lesions in study patients and compared with those of other radiological and/or cytological investigations. Nine of 19 patients (47.4%) showed pathological [18F]-FDG (5/19, 26.3%) or [124I]-PET (4/19, 21.1%) uptake, and were classed as true-positives. Among such patients, disease management was modified in six (66.7%) and disease was restaged in seven (77.8%). In particular, the use of the described imaging combination optimized planning of surgical resection to deal with locoregional recurrence in 21.1% (4/19) of patients, who were shown to be disease-free during follow-up after surgery. Our results indicate that combination of [18F]-FDG-PET/CT and [124I]-PET/CT affords a valuable diagnostic method that can be used to make therapeutic decisions in patients with DTC who are tumor-free on conventional imaging studies but who have high Tg levels.