Growth Rates of Pulmonary Carcinoid Tumors and Hamartomas.

BACKGROUND: Pulmonary nodule growth is often measured by volume doubling time (VDT), which may guide management. Most malignant nodules have a VDT of 20 to 400 days, with longer VDTs typically observed in indolent nodules. We assessed the utility of VDT in differentiating pulmonary carcinoids and hamartomas. METHODS: A review was performed from January 2012 to October 2021 to identify patients with pathologic diagnoses and at least 2 chest computed tomography scans obtained 6 or more months apart. Visualization software was used to segment nodules and calculate diameter and volume. Volume doubling time was calculated for scans with 1-mm slices. For the remainder, estimated nodule volume doubling time (eVDT) was calculated using nodule diameter. Volume doubling times/eVDTs were placed into growth categories: less than 400 days; 400-600 days; and more than 600 days. RESULTS: Sixty nodules were identified, 35 carcinoids and 25 hamartomas. Carcinoids were larger than hamartomas (median diameter, 13.5 vs 11.5 mm; P = 0.05). For carcinoid tumors, median VDT (n = 15) was 1485 days, and median eVDT (n = 32) was 1309 days; for hamartomas, median VDT (n = 8) was 2040 days and median eVDT (n = 25) was 2253 days. Carcinoid tumor eVDT was significantly shorter than hamartomas ( P = 0.03). By growth category, 1 of 25 hamartomas and 5 of 35 carcinoids had eVDT less than 400 days and 24 of 25 hamartomas and 27 of 35 carcinoids had eVDT more than 600 days. Of 4 carcinoid tumors with metastases, 2 had eVDT less than 400 days and 2 had eVDT more than 600 days. CONCLUSIONS: Growth rate was not a reliable differentiator of pulmonary hamartomas and carcinoids. Slow growing carcinoids can metastasize. Radiologists should be cautious when discontinuing computed tomography follow-up based on growth rates alone.

Complications in image-guided musculoskeletal injections.

OBJECTIVE: To establish the incidence and define the nature of complications occurring following image-guided musculoskeletal injections at our institution. MATERIALS AND METHODS: All patients undergoing image-guided musculoskeletal injection during the study period (16/3/2016 to 24/01/2020) were included. Departmental records were reviewed to identify all patients describing possible complications following injection, what therapy was required (if any) and what the outcome was. No patients were excluded. Complications were classified as minor or major. Injections were categorised as follows: cervical spine, lumbar facet joint, lumbar nerve root, caudal epidural and 'other'. The complication rate for each individual category of procedure was compared with the combined complication rate for all other categories by constructing contingency tables and using Fisher's exact test. RESULTS: A total of 8226 patients underwent image-guided musculoskeletal injections within the study period. Exactly 100 patients were identified as having reported a complication, producing an overall complication rate of 1.2%. One complication was categorised as 'major', with the patient requiring expedited surgery. The remainder (99 patients) were categorised as having experienced minor complications. The incidence of complications after 'other' injections was significantly greater than for other categories of injection (1.86%, p = 0.028). There was no significant difference in the complication rate for cervical spine (0.93%, p = 0.257), lumbar nerve root (0.85%, p = 0.401), lumbar facet joint (0.67%, p = 0.326) or caudal epidural (1.29%, p = 0.687) injections. 'Other' injections were subsequently further sub-categorised by anatomical site and imaging modality used. Glenohumeral (2.97%, p = 0.0361) and sacro-iliac (3.51%, p = 0.0498) joint injections were associated with a significantly increased risk of complications. There was no difference in the incidence of complications with fluoroscopic or ultrasound guidance. CONCLUSION: In conclusion, image-guided musculoskeletal injections are safe and well-tolerated procedures. Complications are rare, occurring in just 1.2% of patients. 99% of complications are minor, either not requiring intervention or resolving with simple supportive treatment.

MRI safety management in patients with cardiac implantable electronic devices: Utilizing failure mode and effects analysis for risk optimization.

INTRODUCTION: Cardiac implantable electronic devices (CIEDs) are increasing in prevalence. Exposing patients with CIEDs to magnetic resonance imaging (MRI) can lead to adverse outcomes. This has led certain radiology departments to not accept MRI referrals related to patients with CIEDs. Patients with MR-conditional CIEDs can be safely scanned under specific conditions. Our institution has accepted such referrals since 2014. The aim of this study was to systematically identify and reduce risk in our CIED-MRI protocol using failure mode and effects analysis (FMEA). METHODS: A multidisciplinary FMEA team was assembled and included senior stakeholders from the CIED-MRI protocol. A process map was constructed followed by risk analysis and scoring. Targeted interventions were formulated and implemented; high-risk failure modes were prioritized. A new process map and protocol were drafted and repeat risk analysis was performed. Monitoring and re-evaluation of the CIED-MRI pathway were instigated at departmental quality assurance (QA) meetings. RESULTS: Interventions included direct CIED characterization using wireless technology pre-MRI, CIED programming and reprogramming in the MRI suite before and immediately after MRI reducing device downtime and continuous patient monitoring during MRI by a cardiac physiologist. The cumulative risk priority number (RPN) decreased from 1190 pre-FMEA to 492 post-FMEA. DISCUSSION: Despite the risk of exposing CIEDs to the MR environment, patients with MR-conditional CIEDs can be safely scanned with an appropriate multidisciplinary support. We found FMEA an indispensable tool in identifying and minimizing risk with no adverse events recorded since FMEA recommendations were implemented.

Mass casualty incidents-are you ready? A major incident planning template for diagnostic radiology.

Mass casualty incidents (MCIs) create a large number of casualties in a short period of time. Diagnostic radiology plays an important role in major incident responses but is often underrepresented during major incident planning (MIP) and simulation. Surveys suggest radiologists are unfamiliar with their role during an MCI. We aimed to identify key topics for radiology MIP, familiarize radiologists with their role during an MCI and identify areas for future research. The terms "radiology" and "mass casualty incident" were entered into the advanced search builder on PubMed. Abstracts from this primary search were reviewed and papers selected for inclusion. Additional studies of interest were identified upon review of reference sections of relevant articles and from the related article tab on PubMed. MCI and trauma guidelines were reviewed. Key factors that caused issues during prior MCIs were identified including staff alert mechanisms, patient identification strategies, patient tracking, scan ordering and result communication. Limitations of local imaging resources and capacity should be identified and inform plans for the utilization of diagnostic radiology in the MCI setting. Simulation can help identify areas for improvement and familiarize staff with their roles. Further development of reliable MCI alert technology and patient identification strategies are needed as well as prospective validation of trauma CT selection criteria to identify patients who will benefit most from CT. Radiology should take part in MIP to address key issues encountered during prior MCIs and in MCI simulation to optimize major incident response.

Evidenced-based radiology? A single-institution review of imaging referral appropriateness including monetary and dose estimates for inappropriate scans.

BACKGROUND: There has been a year on year increase in imaging requests at our academic institution. The iRefer guidelines are produced by the Royal College of Radiologists in the UK and are designed to prevent inappropriate imaging and radiation exposure. They have been available to general practitioners and hospital physicians in Ireland since March 2015. AIMS: Our aims were to determine the proportion of inappropriate imaging referrals pre- and post-guideline introduction and to calculate the cost and dose estimates for inappropriate scans. METHODS: A retrospective review of 1124 radiographs was performed with reference to a validated audit template. Emergency department, in-patient, and general practitioner referrals were reviewed. Cost and cumulative dose estimates were calculated for inappropriate referrals taking into account salaries, average time spent performing/reporting radiographs, and median effective dose values. RESULTS: The introduction of the iRefer guidelines has not significantly affected the proportion of inappropriate radiograph referrals at our institution, 42% pre-introduction and 43% post-introduction. We identified 784 inappropriate referrals across 6 radiograph subtypes, imparting a total median effective dose of 65.1 mSv to patients. The time spent performing inappropriate abdominal and spinal radiographs in 2017 yielded an estimated cost of €8036.40. CONCLUSION: A significant amount of inappropriate radiographs continue to be requested and performed, exposing patients to needless ionizing radiation and wasting staff members time at a financial cost. Interventions are needed to decrease inappropriate referrals.

What Are the Indications for Prophylactic Embolization of Renal Angiomyolipomas? A Review of the Current Evidence in the Literature.

Renal angiomyolipomas (AMLs) are benign tumours that may occur sporadically in the general population or in patients with tuberous sclerosis complex. The concern with AMLs is that of retroperitoneal hemorrhage, which can be fatal. Classically the trigger for prophylactic intervention was thought to be an AML diameter of ≥4 cm. However, this value is largely based on data from case series and heterogeneous retrospective studies. The PICO (patient, intervention, comparison, outcome) paradigm was used to systematically search the Cochrane database, TRIP database, and PubMed. The quality of evidence in the literature is poor regarding the indications for prophylactic embolization of AMLs (level 4). There are no prospective studies that adequately assess embolization vs other treatment modalities. However, using the available evidence we have produced recommendations for when intervention should be considered. We have also made recommendations regarding the direction of future research.

Understanding the Limiting Factors of Solvent-Annealed Small-Molecule Bulk-Heterojunction Organic Solar Cells from a Chemical Perspective.

A detailed account of the limiting factors of solvent-annealed bulk-heterojunction small-molecule organic solar cells is given. This account is based on the extensive characterisation of solar cell devices made from a library of five diketopyrolopyrole (DPP) donor dyes. Their chemical structure is designed in such a way as to provide insights into the energetics of solar cell active layer micro-structure formation. Numerous chemical and physical properties of the active layers are assessed and inter-related such as light absorption, molecular packing in the solid state, crystal-forming properties in thin films, charge carrier mobility and charge carrier recombination kinetics. A myriad of characterisation techniques are used such as UV/Vis absorption spectroscopy, photoluminescence spectroscopy, XRD, AFM and photo-induced transient measurements, which provide information on the optical properties of the active layers, morphology and recombination kinetics. Consequently, a mechanism for the solvent-vapour-annealing-assisted formation of crystalline domains of donor molecules in the active layer is proposed, and the micro-structural features are related to the J-V characteristics of the devices. According to this model, the crystalline phase in which the donor crystallise in the active layer is the key determinant to direct the formation of the micro-structure.

Observation of Quantum Confinement in Monodisperse Methylammonium Lead Halide Perovskite Nanocrystals Embedded in Mesoporous Silica.

Hybrid organic-inorganic metal halide perovskites have fascinating electronic properties and have already been implemented in various devices. Although the behavior of bulk metal halide perovskites has been widely studied, the properties of perovskite nanocrystals are less well-understood because synthesizing them is still very challenging, in part because of stability. Here we demonstrate a simple and versatile method to grow monodisperse CH3NH3PbBrxIx-3 perovskite nanocrystals inside mesoporous silica templates. The size of the nanocrystal is governed by the pore size of the templates (3.3, 3.7, 4.2, 6.2, and 7.1 nm). In-depth structural analysis shows that the nanocrystals maintain the perovskite crystal structure, but it is slightly distorted. Quantum confinement was observed by tuning the size of the particles via the template. This approach provides an additional route to tune the optical bandgap of the nanocrystal. The level of quantum confinement was modeled taking into account the dimensions of the rod-shaped nanocrystals and their close packing inside the channels of the template. Photoluminescence measurements on CH3NH3PbBr clearly show a shift from green to blue as the pore size is decreased. Synthesizing perovskite nanostructures in templates improves their stability and enables tunable electronic properties via quantum confinement. These structures may be useful as reference materials for comparison with other perovskites, or as functional materials in all solid-state light-emitting diodes.

Increased efficiency in small molecule organic solar cells through the use of a 56-π electron acceptor--methano indene fullerene.

Organic solar cells (OSCs) offer the possibility of harnessing the sun's ubiquitous energy in a low-cost, environmentally friendly and renewable manner. OSCs based on small molecule semiconductors (SMOSCs)--have made a substantial improvement in recent years and are now achieving power conversion efficiencies (PCEs) that match those achieved for polymer:fullerene OSCs. To date, all efficient SMOSCs have relied on the same fullerene acceptor, PCBM, in order to achieve high performance. The use of PCBM however, is unfavourable due to its low lying LUMO level, which limits the open-circuit voltage (VOC). Alternative fullerene derivatives with higher lying LUMOs are thus required to improve the VOC. The challenge, however, is to prevent the typical concomitant decrease in the short circuit current density (JSC) when using a higher LUMO fullerene. In this communication, we address the issue by applying methano indene fullerene, MIF, a bis-functionalised C60 fullerene that has a LUMO level 140 mV higher than PCBM, in solution processed SMOSCs with a well known small molecule donor, DPP(TBFu)2. MIF-based devices show an improved VOC of 140 mV over PC61BM and only a small decrease in the JSC, with the PCE increasing to 5.1% (vs. 4.5% for PC61BM).

Influence of the molecular weight and size dispersion of the electroluminescent polymer on the performance of air-stable hybrid light-emitting diodes.

The influence of the chain length and the molecular weight distribution of the electroluminescent polymer on the carrier transport properties and morphology of air stable hybrid light-emitting diodes is reported. It is found that variations between diverse as-received commercial batches play a major role in the performance of the devices, whose maximum luminance can differ up to 2 orders of magnitude. Through complementary optoelectronic, structural, and morphological characterization techniques, we provide insights into the relationship between charge dynamics and the structure of polymeric electroluminescent materials. The carrier dynamics are found to be dominated by both the polymeric chain length and the hole transport, which in turn is dependent on the concentration of trap states. Furthermore, the chain length is seen to affect the morphology of the active layer.

Approach to high open-circuit voltage in organic solar cells utilizing a structural change of the oxazolino-C70 derivative.

Reactions of 2,5-Bn2 C70 (Bn=CH2 Ph) with hydroxide and ArCN (Ar=Ph, m-ClPh) followed by quenching with I2 and BnBr afforded dibenzylated and tetrabenzylated oxazolino[70]fullerenes, respectively. The latter has a novel structural configuration, in which the addends are positioned from the polar to the transequatorial region. A key structural feature of this compound is that the oxygen atom of the oxazoline ring is bound to the equatorial belt region of C70 , giving structural change in its reduced state. This enables stabilization of the reduced state, suppressing charge recombination dynamics in organic solar cells to give a high open-circuit voltage (0.85, 0.93, and 1.11 V in devices using P3HT, PTB7, and DPP(TBFu)2 , respectively).

Small molecule-based tandem solar cells with solution-processed and vacuum-processed photoactive layers.

A tandem solar cell device whose sub-cells are fabricated exclusively from small molecules (SMs) through both solution-processed and vacuum-processed deposition techniques is described. The front sub-cell's active layer consists of a bulk heterojunction (BHJ) DPP(TBFu)2:PC70BM device while the back cell has a typical bilayer structure employing a 2,4-bis[4-(N,N-diisobutylamino)-2,6-dihydroxyphenyl] squaraine (SQ) donor and a C60 acceptor.

Spectroscopic properties of Zn(salphenazine) complexes and their application in small molecule organic solar cells.

A new family of salphen based complexes, viz. Zn(salphenazine)s, has been prepared and is characterized by a larger π-surface compared to previously reported Zn(salphen) complexes. The spectroscopic properties of these Zn(salphenazine)s have been studied in detail using UV-Vis and fluorescence spectroscopy, and further investigated by computational methods. The first application of a Zn(salphenazine) complex in a small molecule organic solar cell (smOSC) is presented showing the potential of salphenazine systems in this area.

In vivo measurement of coronary circulation angiotensin-converting enzyme activity in humans.

Angiotensin-converting enzyme (ACE) is present on the luminal surface of the coronary vessels, mostly on capillary endothelium. ACE is also expressed on coronary smooth muscle cells and on plaque lipid-laden macrophages. Excessive coronary circulation (CC)-ACE activity might be linked to plaque progression. Here we used the biologically inactive ACE substrate (3)H-labeled benzoyl-Phe-Ala-Pro ([(3)H]BPAP) to quantify CC-ACE activity in 10 patients by means of the indicator-dilution technique. The results were compared with atherosclerotic burden determined by coronary angiography. There was a wide range of CC-ACE activity as revealed by percent [(3)H]BPAP hydrolysis (30-74%). The atherosclerotic extent scores ranged from 0.0 to 66.97, and the plaque area scores ranged from 0 to 80 mm(2). CC-ACE activity per unit extracellular space (V(max)/K(m)V(i)), an index of metabolically active vascular surface area, was correlated with myocardial blood flow (r = 0.738; P = 0.03) but not with measures of the atherosclerotic burden. These results show that CC-ACE activity can be safely measured in humans and that it is a good marker of the vascular area of the perfused myocardium. It does not, however, reflect epicardial atherosclerotic burden, suggesting that local tissue ACE may be more important in plaque development.