Injection And Infusion Technology Disruption For Use In MRI.

INTRODUCTION: Contrast media injections, infusions, or experiments that require a constant volume flow close to or within a very high magnetic field like in magnetic resonance imaging (MRI) require a liquid reservoir and a power unit to deliver the fluid. However, most power units are driven by motors that are either not MRI-compatible or require external connections that restrict mobility and usage. In this paper, the development of a highly portable, lightweight, and MRI-compatible pump system is explained. METHODS: The energy required to deliver the flow is generated using a pressurized bottle concept. The valve inside the bottle is opened to create a flow which should be maintained constant. In order to find the optimal flow resistance for a constant flow rate, we created multiple setups with different flow resistance. RESULTS: We measured the flow rates for different flow resistances by attaching a restring valve to the bottle. The results clearly show that high flow resistance results in lower and more constant flow rate. DISCUSSION: The optimal flow rate achieved using our current setup was significantly constant but not ideal. Consequently, such a pump system can be used in many medical applications like MRI-compatible contrast agent injectors.

Texture differentiation using audio signal analysis with robotic interventional instruments.

Robotic minimally invasive surgery (RMIS) has played an important role in the last decades. In traditional surgery, surgeons rely on palpation using their hands. However, during RMIS, surgeons use the visual-haptics technique to compensate the missing sense of touch. Various sensors have been widely used to retrieve this natural sense, but there are still issues like integration, costs, sterilization and the small sensing area that prevent such approaches from being applied. A new method based on acoustic emission has been recently proposed for acquiring audio information from tool-tissue interaction during minimally invasive procedures that provide user guidance feedback. In this work the concept was adapted for acquiring audio information from a RMIS grasper and a first proof of concept is presented. Interactions of the grasper with various artificial and biological texture samples were recorded and analyzed using advanced signal processing and a clear correlation between audio spectral components and the tested texture were identified.

Feedback-based Self-improving CNN Algorithm for Breast Cancer Lymph Node Metastasis Detection in Real Clinical Environment.

Digital pathology can be thought of as a model composed of 3 main elements; classification algorithm, Graphical User Interface (GUI) and the pathologists. Currently there is only a one way interaction from the classification algorithm to the pathologist. This paper, proposes an additional backward path which is a new feedback-based method, aimed to improve the performance of the classification algorithms by utilizing the feedback of the pathologists. The GUI developed for this purpose, is aimed to be simple and adaptive to different classification algorithms. The method showed significant improvement in the classification performance of the applied Convolutional Neural Network (CNN) algorithm. The 25% quantile of the probability score of the predictions increased from 0.48 to 0.89 and the median of the data increased from 0.95 to 0.99.

Passive artifact behavior prediction of interventional tools in high-field MRI using a 0.55T portable benchtop MR scanner.

Using magnetic resonance imaging (MRI) for guiding minimally invasive interventions requires surgical devices which on one hand are visible in the MR image but on the other hand do not generate large artifacts, which distort the overall imaging process. Passive markers are one way to visualize devices such as catheters or biopsy needles in MRI. The evaluation of newly developed passive markers usually requires access to high-field MRI scanners (1.5 T and 3 T). This makes the practical evaluation time-consuming and expensive. Hence, we propose to use a high-resolution, low field (0.55 T) benchtop MRI system to quantify the size of an artifact and to make a prediction for its corresponding size in a clinical high-field system. For the evaluation of the proposed method, catheters coated with different passive marker materials in varying concentrations were imaged in the 0. 55 T benchtop MRI scanner as well as in clinical 3 T MRI system using FLASH sequences. The experimental results revealed that an artifact prediction based on measurements in the 0. 55 T is possible for the tested marker materials. Hence, the proposed approach has a high potential for testing newly developed medical devices at a low cost, in less time and during the development process for fast feedback.

The isolated perfused equine distal limb as an ex vivo model for pharmacokinetic studies.

Even though intra-articular injections play an important role in the treatment of joint-related lameness in horses, little is known about pharmacokinetic properties of substances used. Therefore, an ex vivo model for pharmacokinetic studies was developed using distal forelimbs of slaughtered horses. The extremity was perfused with gassed Tyrode solution for up to 8 h. Tissue viability was confirmed by measurements of glucose consumption, lactate production, and lactate dehydrogenase activity in the perfusate. Standard criteria for tissue viability had been determined in preliminary experiments (n = 11), which also included histological examinations of the joint capsule. As the model's first implementation, the articular efflux rate of betamethasone (BM), administered as BM disodium phosphate intra-articularly to the fetlock joint (4 mg BM/joint), was investigated. The concentration of BM in the venous perfusate of the radial vein was measured by means of high-performance liquid chromatography. The average BM efflux rate per minute was calculated to be 5.1 µg/min with values ranging from 9 µg/min to 2.9 µg/min. 7.5 h after i.a. application, 2.3 mg BM had left the joint via the radial vein. Using this inexpensive setup, the presented model allows studying a variety of pharmacological topics without the ethical limitations of animal studies.

[Evaluation of an interactive breath-hold control system in CT-guided lung biopsy]. / Evaluation eines interaktiven Atemkontrollsystems bei der CT-gesteuerten Lungenbiopsie.

PURPOSE: In this study we assessed the effect of an interactive breath-hold control system on procedure time and technical success in transthoracic CT-guided lung biopsies. MATERIALS AND METHODS: In 36 patients (4 female, 32 male, mean age 65 years; range 33 - 88) with a pulmonary nodule, we performed CT-guided biopsy using a 18G Tru-cut needle (Cardinal Health, Dublin, UK) in a 64 row dual-source CT scanner (Somatom Definition, Siemens, Forchheim, Germany) using intermittent imaging of the needle. In half of the patients (2 female, 16 male, mean age 67 years), an interactive breath-hold control system (IBC) (Mayo Clinic Medical Devices, USA) was applied. No additional device was used in the control group. RESULTS: The biopsy was visually successful in all patients. The diameter of the target lesion was comparable in both groups (IBC: 30 +/- 19 mm; control: 28 +/- 15 mm). The number of imaging steps was significantly smaller (p < 0.05) and the intervention time was significantly shorter (p < 0.05) in the IBC group (IBC: 9 +/- 5 steps 17 +/- 10 min; control: 13 +/- 5 steps 26 +/- 12 min). CONCLUSION: Application of the IBC unit reduced the intervention time and radiation exposure in CT-guided Tru-cut biopsy of pulmonary nodules.

[99mTc]oxotechnetium(V) complexes amine-amide-dithiol chelates with dialkylaminoalkyl substituents as potential diagnostic probes for malignant melanoma.

[99mTc]oxotechnetium(V) complexes of amine-amide-dithiol (AADT) chelates containing tertiary amine substituents were synthesized and shown to have affinity for melanoma. For complexation the AADT-CH2[CH2]nNR2 (n = 1, 2; R = Et, n-Bu) ligand was mixed with a [99mTc]oxotechnetium(V)-glucoheptonate precursor to make the AADT-[99mTc]oxotechnetium(V) complexes in nearly quantitative yield. Structurally analogous nonradioactive oxorhenium(V) complexes were also synthesized and characterized. In vitro sigma-receptor affinity measurements indicate these complexes to possess sigma-affinity in the low micromolar range with K(i) values in the 7.8-26.1 and 0.18-2.3 microM range for the sigma1- and sigma2-receptors, respectively. In vitro cell uptake of the 99mTc complexes in intact B16 murine melanoma cells at 37 degrees C after a 60-min incubation ranged from 12% for complex 2 (n = 1, R = n-Bu) to 68% for complex 4 (n = 2, R = n-Bu). In vivo evaluation of complexes 1-Tc-4-Tc in the C57Bl/B16 mouse melanoma model demonstrated significant tumor localization. Complex 1-Tc (n = 1, R = Et) displayed an in vivo tumor uptake of 7.6% ID/g at 1 h after administration with initial melanoma/blood (M/B), melanoma/spleen (M/S), and melanoma/lung (M/L) ratios >4; these ratios increased to 10.8, 10.1, and 7.3, respectively, at 6 h. While complex 3-Tc (n = 3, R = Et) had an initial tumor uptake of 3.7% ID/g 1 h after administration with M/B, M/S, and M/L ratios >2, a greater tumor retention and slightly faster clearance from nontumor-containing organs resulted in M/B, M/S, and M/L ratios of 19.1, 19.1, and 12.7, respectively, at 6 h. The high tumor uptake and significant tumor/nontumor ratios indicate that such small technetium-99m-based molecular probes can be developed as in vivo diagnostic agents for melanoma and its metastases.

[Acute gastrointestinal bleeding caused by distinct small intestinal diverticulosis]. / Akute Gastrointestinalblutung bei ausgeprägter Dünndarmdivertikulose.

HISTORY AND CLINICAL FINDINGS: A 58-year-old man was admitted to our hospital after an acute onset of rectal bleeding. He was known to have had recurrent duodenal ulcerative disease, once with upper gastrointestinal haemorrhage. Clinical examination was remarkable only for rectal bleeding. INVESTIGATIONS: After application of a nasogastric tube cherry-red blood was evacuated. Upper endoscopy showed only very small mucosal erosion in the stomach and coloscopy demonstrated several non-bleeding diverticula. Small bowel enteroclysis showed severe diverticulosis of the duodenum and jejunum. DIAGNOSIS, TREATMENT AND COURSE: We assumed that the extensive duodenojejunal diverticulosis was the most probable cause of this episode of gastrointestinal bleeding because of simultaneous signs of upper and lower gastrointestinal haemorrhage. Because this was the first such episode we preferred a conservative approach. At nineteen months follow-up there was no recurrence of bleeding. CONCLUSION: Gastrointestinal hemorrhage is a common cause of hospitalization. After exclusion of the more common bleeding sources small bowel diverticula should be considered as a possible rare cause. Surgical resection of the bleeding bowel part is the procedure of choice, but one of the major problems in such cases is to locate exactly the bleeding site. If the location is uncertain, a more conservative approach may be preferable, especially in haemodynamically stable patients with first-time diverticular bleeding.

Permeation studies in vitro and in vivo of potential radiopharmaceuticals with affinity to neuro receptors.

PURPOSE: To check the influence of structural characteristics on their permeation through the blood-brain barrier (BBB), a set of radioactive [99mTc]chelates bearing amine groups was synthesized and tested in vitro as well as in vivo. METHODS: Compounds with different log P and pKa values were obtained by complex forming reactions of [99mTc]pertechnetate with varying substituents. Transport was studied in rats and mice, as well as in an ECV304 cell culture model. RESULTS: In vitro higher permeation was found for compounds with electron attracting substituents in beta-position to the amine group (pKa values 7.4 to 8.3) than for those with more basic amine groups (pKa values > 8.9) even for similar log DH 7.4. In vivo brain uptake between 0.8 and 4.8% of the injected dose (ID) per organ was found for the former, whereas <0.4% ID were present for the latter. CONCLUSIONS: Three structurally diverse classes of [99mTc]chelates showed distinct patterns with regard to brain uptake in vivo and BBB permeability in vitro which could not be predicted by their lipophilicity alone. The close correlation between the data from rats and mice and those obtained with cell cultures render the ECV304 cells an attractive model for the screening of new compounds.

'3+1' mixed-ligand oxotechnetium(V) complexes with affinity for melanoma: synthesis and evaluation in vitro and in vivo.

'3+1' Mixed-ligand [(99m)Tc]oxotechnetium complexes with affinity for melanoma were synthesized in a one-pot reaction. Complexation of technetium-99m with a mixture of N-R(3-azapentane-1,5-dithiol) [R = Me, Pr, Bn, Et(2)N(CH(2))(2)] and N-(2-dialkylamino)ethanethiol [alkyl = X = Et, Bu, morpholinyl] using Sn(2+) as the reducing agent resulted in the formation of '3+1' mixed-ligand technetium-99m complexes [TcO(SN(R)S)(SNX(2))] in high radiochemical yield (60-98%). In vitro uptake studies in B16 murine melanoma cells indicated a moderate tumor-cell accumulation (40%) of compound 1 [R = Me, X = Et] and a higher accumulation (69%) of compound 2 [R = Me, X = Bu] after a 60-min incubation. In vivo evaluation of compounds 1-6 in the C57Bl6/B16 mouse melanoma model demonstrated tumor localization. Compound 2 displayed the highest accumulation with up to 5% ID/g at 60 min after injection. In vivo, 2 also showed a low blood-pool activity and high melanoma/spleen (4.3) and melanoma/lung (1.9) ratios at 1 h. These results suggest that small technetium-99m complexes could be useful as potential melanoma-imaging agents.

Determination of dissociation constants of 99mTechnetium radiopharmaceuticals by capillary electrophoresis.

Capillary electrophoresis was applied to investigate pKa values of 99mTc radiotracers used in nuclear medicine. Therefore, the protonation equilibria of the carboxyl groups of 99mTc-mercaptoacetylglycylglycylglycine (99mTc-MAG3) and 99mTc-ethylenecysteine dimer (99mTc-EC) were studied by pH-dependent determination of electrophoretical velocities. 99mTc-ethylenecysteine dimer diethyl ester (99mTc-ECD) was used as a non-protonable standard. The capillary electrophoresis system was equipped with a radioactivity detector. Measurements were performed using a pressure-driven capillary zone electrophoresis which allowed runs even in the low pH range. For the determination of pKa values, the electrophoretical velocities of the analytes were referred to the electrophoretical velocities of tetraphenyle arsonium chloride as a positively charged marker. Calculation of pKa values was accomplished by non-linear curve fitting of both structure-based equilibria equations and sigmoidal decay functions to the experimental data. 99mTc-MAG3 was shown to have a carboxyl group pKa value of 4.22. The value for the carboxyl groups of 99mTc-EC is 2.90 (determined by structure-based equilibria equations), which represents a common value for both carboxyl groups. By the use of sigmoidal functions, similar values were elucidated. As expected, 99mTc-ECD shows no protonation step.

The ups and downs for children with chronic illnesses.

Children with chronic illnesses have the same basic need for preventive care as their healthy peers. In Michigan a Medicaid Physician Sponsor Plan was established to provide that care for this special population. Incentives and barriers for both physicians and families were identified as well as the advantages to providing care in a managed care delivery system.