Patients' Perspectives on Shared Decision-Making About Medications in Psoriatic Arthritis: An Interview Study

OBJECTIVE

Decision-making regarding medications to manage psoriatic arthritis (PsA) is complex because of multiple disease manifestations and comorbidities. Fear of side effects from systemic medications and misalignment in priorities between patients with PsA and rheumatologists makes shared decision-making challenging. We aimed to describe the perspectives of patients with PsA on shared decision-making regarding medication taking.

METHODS

Face-to-face semistructured interviews were conducted with 25 adult patients with PsA in Australia. Transcripts were thematically analyzed.

RESULTS

Five themes were identified: lacking agency in decision-making (denied choice, knowledge asymmetry, desperation and necessity, restricted by unfair eligibility criteria, automated approach); overwhelmed by potential harms (daunted by aggressive therapy, anticipating lifestyle disruption from side effects, jeopardizing fertility and pregnancy, avoiding relapse); gaining confidence (discernible benefit in function and mental health, sharpening knowledge over time, expertise of family and peers, empowered by information); opting for alternatives (pursuing normality, suspicion of over-medicalization, seeking comprehensive solutions); and developing trust and fortifying collaboration (assurance through a personable approach, seeking consistency, supported in decisional power, resolution through respectful negotiation).

CONCLUSION

Patients with PsA lack agency in making treatment decisions and are overwhelmed by the potential harms of systemic medication. Improving knowledge and trust with medical teams in a supportive and collaborative environment, and strategies for managing risks and side effects may improve decision-making about pharmacologic management of PsA.

Implementation and Safety of a Single Fraction Peripheral Lung SBRT during the Global COVID-19 Pandemic, a Single Institution's Experience

Purpose/Objective(s)

In response to the COVID-19 pandemic, a single fraction peripheral lung SBRT program was established to minimize potential COVID-19 exposures. This analysis aims to review clinical and treatment characteristics and associated toxicities in appropriately selected patients for this newly implemented technique.

Materials/Methods

From May 2020 until Feb 2022, patients with peripheral lung tumors who met eligibility for 3400cGy in a single-fraction SBRT were treated at a tertiary academic cancer center. Patient, treatment, and toxicity parameters were retrospectively collected. Radiation dosimetric parameters were tabulated. Toxicities were quantified using CTCAE v5.0. Fisher's exact test was used to assess the differences in toxicities with clinical and dosimetric parameters. P-value < 0.05 was considered significant.

Results

23 patients were analyzed with a median age of 72 years (IRQ: 67-80) and 61% were females. 96% were smokers and 43% had COPD. All patients were ECOG ≤ 2. Majority of patients (96%) had early-stage primary lung cancer while 4% had pulmonary oligometastatic cancer. 39% of patients were treated on SABR-BRIDGE protocol while another 35% were medically inoperable and 26% refused surgery. A total of 23 peripheral lesions were treated with median greatest dimension of 1.7 cm (IQR: 1.4-2), ITV 4.9 cm³ (IQR: 3.6-8.4) and PTV 18.1 cm³ (IQR: 12.8-26). 87% had PTV within 1 cm form chest wall. After median follow-up of 6 months (IQR: 2-12), 52% of patients experienced grade ≤ 2 toxicities and no patients experienced ≥ grade 3. Radiation pneumonitis was the most common toxicity (35%; 5/8 with asymptomatic radiographic) followed by fatigue (30%) and chest wall pain (30%; 3/7 with grade 2). Two patients (9%) had rib fractures. Chest wall pain was significantly higher in patients with tumor diameter >1.5 cm (p = 0.02). No other significant difference was observed between clinical or dosimetric parameters and development of radiation pneumonitis or chest wall pain (p > 0.05). On the other hand, patients with ribs fractures were observed to have larger tumors (mean 3.2 vs. 1.7 cm), ITVs (mean 30 vs. 11 cm³), PTVs (mean 61 vs. 16 cm³), chest wall V30_Gy (mean 4.8 vs. 0.4 cm³), and ribs V30_Gy (mean 1.1 vs. 0.1 cm³). Only 1 patient had local failure after 12 months while another patient on SABR-BRIDGE underwent surgical resection after 6 months in which there were 20% viable tumor cells.

Conclusion

Single fraction peripheral lung SBRT is a practical and safe option with no grade ≥ 3 toxicity. Our observed toxicities are within previously reported ranges. We observed that patients with rib fractures had larger tumors and higher V30_Gy to chest wall and ribs. Careful patient selection and dosimetric efforts to limit high fall-off dose to chest wall and ribs may limit these toxicities.

POS1034 EVOLVING MECHANISM OF ACTION PREFERENCE FOR THE TREATMENT OF PSORIATIC ARTHRITIS IN AUSTRALIA: AN ANALYSIS OF THE OPAL DATASET

Background

There are currently ten biologic and targeted synthetic (b/ts)DMARDs acting via five different modes of action (MOA) available for the treatment of psoriatic arthritis (PsA) in Australia. b/tsDMARDs are government-subsidised, and once the patient reaches the eligibility requirements, the clinician can prescribe the agent deemed most appropriate. Available agents include TNF inhibitors (TNFi, adalimumab, etanercept, infliximab, golimumab, certolizumab pegol), IL-17A inhibitors (IL-17Ai, secukinumab, ixekizumab), and IL-12/23 inhibitor (IL-12/23i, ustekinumab). Two new MOAs were recently added to the rheumatologist’s armamentarium: the first JAK inhibitor (JAKi, tofacitinib) was subsidized from May 2019 followed by upadacitinib from Oct 2021, and an IL-23 inhibitor (IL-23i, guselkumab) was subsidized from July 2021.

Objectives

The aim of this analysis was to describe the changing patterns of b/tsDMARD use for the treatment of PsA in real-world practice in Australia.

Methods

Deidentified clinical data were sourced from the OPAL dataset, which is collected in a custom-built electronic medical record during the routine consultation1. Data from patients >18 years with a physician diagnosis of PsA who were prescribed a b/tsDMARD between Jan-2007 and Sept-2021 were included in the analysis. The software program Tableau was used to display the data.

Results

At Sept 2021, 6,150 (38% of the total) patients with PsA in the OPAL dataset were prescribed b/tsDMARDs. Of these patients, 3741 (61%) were currently prescribed a TNFi, 1503 (24%) an IL-17Ai, 556 (9%) a JAKi, 222 (4%) an IL-12/23i and 134 patients (2%) an IL-23i. Over time, the 1st line TNFi initiations have decreased from 79.5% in 2018 to 65.2% in 2021. Conversely, 1st line IL-17Ai initiations have increased from 14.4% in 2018 to 22.2% in 2021. In 2021, TNFi accounted for 53.4% of 2nd line initiations and 38.2% of 3rd line initiations. IL-17Ai accounted for 30.4% of 2nd and 37.0% of 3rd line initiations and JAKi accounted for 10.5% of 2nd line and 14.2% of 3rd line initiations. In the 3 months that IL-23i has been subsidised, this MOA was the most initiated agent for patients who had been treated with more than two prior b/tsDMARDs. In 2021, 52.1% of patients switching from a 1st line TNFi switched to an alternative TNFi, 33.3% switched to an IL-17Ai and 11.3% switched to a JAKi in 2nd line. Of those switching from a 1st line IL-17Ai, 59.6% initiated a TNFi, 21.2% switched to an alternative IL-17Ai and 11.5% switched to a JAKi.

Conclusion

The patterns of b/tsDMARD utilisation for the treatment of PsA, when the choice of agent is at the discretion of the rheumatologist, remains dynamic and is evolving as new MOAs become available. TNFi remains the most prescribed b/tsDMARD for first line therapy. However an increase in first line use of alternative MOAs has been observed. TNFi cycling remains a commonly utilised real world treatment strategy but appears to be declining as new MOAs become available.

References

[1]Littlejohn GO, Tymms KE, Smith T, Griffiths HT. Using big data from real-world Australian rheumatology encounters to enhance clinical care and research. Clin Exp Rheumatol. Sep-Oct 2020;38(5):874-880.

Figure 1.

Percentage of patients initiating b/tsDMARDs by year and line of therapy.

Acknowledgements

The authors acknowledge the members of OPAL Rheumatology Ltd and their patients for providing clinical data for this study, and Software4Specialists Pty Ltd for providing the Audit4 platform.

Disclosure of Interests

Peter Youssef Speakers bureau: AbbVie, Novartis, Eli Lilly, Sabina Ciciriello: None declared, Gene-Siew Ngian: None declared, Juan Aw: None declared, Barry Kane: None declared, Catherine OSullivan: None declared, Tegan Smith: None declared, Claire Deakin: None declared, Geoff Littlejohn Consultant of: Abbvie, Janssen, Bristol Myers Squibb, Gilead, Eli Lilly, and MSD

Correlation of patient-reported routine assessment of patient index data with clinical measures of disease activity in psoriatic arthritis

Aim

A treat‐to‐target strategy is recommended for management of psoriatic arthritis (PsA), although there is lack of agreement regarding the best measure of disease activity to target. Physician assessments included in traditional indices can be complex and time consuming to complete and cannot be readily conducted by telehealth. This study compares the routine assessment of patient index data 3 (RAPID3), an efficient tool comprising patient self‐assessment, with traditional clinician‐led composite measures in the PsA clinic setting.

Methods

Data were collected prospectively from July 2016 to March 2020 in 2 dedicated PsA clinics in Sydney, Australia. A receiver operating characteristic (ROC) curve was created for comparison of RAPID3 score with composite scores minimal disease activity (MDA), very low disease activity (VLDA) and disease activity in psoriatic arthritis (DAPSA) in low disease activity or remission.

Results

Ninety‐three patients had simultaneous collection of RAPID3 and MDA measures. Mean (SD) age was 49.9 (13.5) years, 50.5% were male and 23 (24.7%) had erosive disease at baseline. RAPID3 scores ≤3.2 and ≤2.7 (range 0‐30) had high sensitivity and specificity for VLDA and DAPSA remission respectively, with ROC curve area under the curve (95% CI) of 0.94 (0.91‐0.97) and 0.96 (0.93‐0.99).

Conclusion

RAPID3 has good agreement with physician‐led composite scores of MDA, VLDA and DAPSA, and provides a viable alternative to composite scores. This is particularly helpful in settings that do not allow for clinical examination, for example telehealth.

Preferences for biologic treatment in patients with psoriatic arthritis: a discrete choice experiment

OBJECTIVES

We aimed to assess patient preferences for the characteristics and outcomes of biologic and targeted synthetic DMARDs to manage psoriatic arthritis.

METHODS

We conducted a discrete choice experiment in patients with psoriatic arthritis from three rheumatology centers in Sydney, Australia. We assessed preferences for different attributes of biologic medications. The route and frequency of medications had a range of five levels and the following seven attributes had a range of three levels: the ability to attend to normal activities, improvements in joint pain, enthesitis and skin disease, chance of disease remission, risk of infection and risk of severe adverse events. Multinomial logit models including a latent class model were used to calculate preferences.

RESULTS

Of the 150 participants, 58.3% were female, with a median age of 53.5 years. The attributes in order of preference were (β coefficient in absolute values, 95% confidence interval): oral route compared to subcutaneous and intravenous routes (β coefficient 1.00, fixed-parameter), avoiding severe side effects (0.72, 0.50 to 0.95), increasing ability to attend to normal activities (0.66, 0.36 to 0.96), avoiding infections (0.38, 0.23 to 0.53), improvement in enthesitis pain (0.28, 0.20 to 0.36), improvement in psoriasis (0.28, CI 0.20 to 0.36), increasing chance of remission (0.27, 0.19 to 0.36) and improvement in joint pain (0.26, 0.00 to 0.52).

CONCLUSION

When choosing biologic medications, patients with psoriatic arthritis preferred oral medications. Patients prioritized avoiding severe complications, maintaining the ability to attend to work and normal activities and avoiding infection over clinical measures of efficacy.

[Dysthyroidism in children and adolescents at the Mali hospital]

INTRODUCTION

Dysthyroidism (hyperthyroidism or hypothyroidism) in children and adolescents is much rarer than in adults. The purpose of our study was to study the epidemiological, clinical, paraclinical, etiological and etiological aspects and to specify the therapeutic and evolutionary modalities of this condition.

METHOD

This was a five-year descriptive, retrospective and prospective study of children and adolescents under 18 years of age with dysthyroidism.

RESULTS

We collected 90 children and adolescents with dysthyroidism (hyperthyroidism 77.8% (n=70) and hypothyroidism 22.2% (n=20). For hyperthyroidism (n=70): the average age was 13.07 years and the sex ratio was 0.16. The family history of dysthyroidism was found in 24.3% (n=17). Clinical manifestations were dominated by tachycardia 88.57% (n=62), weight loss 87.14% (n=61), vibrating pulse 87.14% (n=61) and palpitation 81.42% (n=57). Bilateral exophthalmos was present in 70% of patients (n=49) with palpebral retraction in 51.42% (n=56). Goitre was present in 54 patients (77.1%). It was diffuse in 62.9% (n=44) and nodular in 12.9% (n=9). Basedow's disease represented the first etiology with 84.3% (n=59), followed by toxic multinodular goitre12, 9% (n=9). Sixty-eight patients (97.1%) received medical treatment with synthetic antithyroid drugs. Clinical remission was achieved in 64.3% (n=45) and 54.3% of patients were in biological euthyroidism at 6 months follow-up. For hypothyroidism (n=20): the average age was 10.70 years and the sex ratio was 0.53. Six family cases of hypothyroidism and three cases of family goitre were found. The clinical picture was dominated by signs of hypo metabolism at hypersomnia type 95% (n=19) and anorexia 75% (n=15). The skin was dry in 60% (n=12). A staturo-weight delay in 65% (n=13), behavioural disorders in 55% (n=11), weight gain in 40% (n=8) and puberty delay in 10% (n=2). Goitre was nodular in 25% (n=5) with cervical adenopathy present in 15% (n=3). Hashimoto's thyroiditis accounted for 45% (n=9) of etiologies followed by iodine deficiency disorders in 15% (n=3) and iatrogenic causes (2 cases of thyroidectomy). All patients were started on hormone replacement therapy for life. Five patients with large multinodular goiter received total thyroidectomy in addition to medical treatment. Euthyroidism was observed in 55% (n=11) of patients at 6 months follow-up.

CONCLUSION

Dysthyroidism in children and adolescents exists in our health facilities. Its management is deficient because of the technical and financial platform. Our public health decision-makers must help implement a screening strategy to facilitate faster diagnosis and treatment.

An architectural understanding of natural sway frequencies in trees

The relationship between form and function in trees is the subject of a longstanding debate in forest ecology and provides the basis for theories concerning forest ecosystem structure and metabolism. Trees interact with the wind in a dynamic manner and exhibit natural sway frequencies and damping processes that are important in understanding wind damage. Tree-wind dynamics are related to tree architecture, but this relationship is not well understood. We present a comprehensive view of natural sway frequencies in trees by compiling a dataset of field measurement spanning conifers and broadleaves, tropical and temperate forests. The field data show that a cantilever beam approximation adequately predicts the fundamental frequency of conifers, but not that of broadleaf trees. We also use structurally detailed tree dynamics simulations to test fundamental assumptions underpinning models of natural frequencies in trees. We model the dynamic properties of greater than 1000 trees using a finite-element approach based on accurate three-dimensional model trees derived from terrestrial laser scanning data. We show that (1) residual variation, the variation not explained by the cantilever beam approximation, in fundamental frequencies of broadleaf trees is driven by their architecture; (2) slender trees behave like a simple pendulum, with a single natural frequency dominating their motion, which makes them vulnerable to wind damage and (3) the presence of leaves decreases both the fundamental frequency and the damping ratio. These findings demonstrate the value of new three-dimensional measurements for understanding wind impacts on trees and suggest new directions for improving our understanding of tree dynamics from conifer plantations to natural forests.

038 Adult-onset leukoencephalopathy with neuroaxonal spheroids and pigmented glia mimicking systemic lupus erythematosus cerebral vasculitis

Introduction

We present an unusual case of adult-onset leukoencephalopathy with neuroaxonal spheroids and pigmented glia (ALSP) mimicking systemic lupus erythematosus (SLE) cerebral vasculitis. ALSP is an autosomal dominant progressive leukodystrophy, associated with mutations in the CSF1R gene, which induce dysregulation of microglia. The case was compiled from records of clinical data, imaging, brain biopsy and genetic studies.

Case

A 56 year old previously high functioning man of Southern Chinese origin was hospitalised with recurrent seizures. He had a prior 4 year history of progressive neuropsychiatric features, and 1 year of cognitive decline and occasional falls. Within the year prior, he had positive SLE serology and a renal biopsy consistent with lupus nephritis treated with steroids, mycophenolate, hydroxyl-chloroquine, and later rituximab due to concerns of evolving cerebral vasculitis on cerebral MRI and SPECT scan with MoCA of 20/30. Examination after seizure therapy revealed hyperreflexia, fine tremor, myoclonus, pseudobulbar affect, ideomotor apraxia and slow, independent gait. RUDAS was 6/30 with perseveration. CSF examination and SLE serology were quiescent. Consecutive brain MRIs showed multiple regions of worsening high T2/FLAIR signal in the corpus callosum and supra-tentorial white matter with persistent restricted diffusion. IV steroids and cyclophosphamide were added. Following treatment unresponsiveness, a frontal lobe brain biopsy demonstrated white matter gliosis with prominent axonal spheroids consistent with a primary leukoencephalopathy, with no inflammation, vasculitis nor infection. Immunotherapy was weaned. Genetic testing confirmed a positive CSF1R mutation (c.2329C>T; p. Arg777Trp in Exon 18). A positive family history of dementia in the patient’s elderly mother overseas was identified. The patient remained mobile but mute, and fatally aspirated 8 months after final presentation.

Conclusion

This report illustrates an unusual presentation of ALSP, initially misdiagnosed as SLE vasculitis. Clinicians should consider an adult onset leukodystrophy and proceed to biopsy and CSF1R gene testing early in suspected ‘refractory cerebral vasculitis’.

Pulsatile flow simulation in arterial vascular segments with intravascular ultrasound images

Previous studies have indicated a correlation between local variation in wall shear stress in arterial blood flow and atheroma development. The purpose of this study was to analyze the hemodynamics in vascular segments from morphologically realistic three-dimensional (3D) reconstruction, and to compare the computed wall shear stress in a compliant vascular segment model and the corresponding rigid walled model. Cross-sectional images of the segments of femoral and carotid arteries in five Yucatan miniswine were obtained using intravascular ultrasound (IVUS) imaging and the segment geometry was reconstructed at different times in the cardiac cycle. The actual measured wall motion from the reconstruction was employed to specify the moving boundaries for simulation of physiological distensibility. Velocity profiles and wall shear stress were computed using unsteady computational fluid dynamics analysis. The computed results revealed that the maximum wall shear stress in the compliant model was approximately 4-17 percent less than that in the rigid model if the wall motion is larger than 10 percent. Our analysis demonstrates that inaccuracies due to inflow velocity profile can be minimized by the extension of the model upstream. The phase angle between the diameter change and wall shear is affected by the local changes in geometry of the arteries. These simulations can be potentially used to analyze the effect of regional wall motion changes in the presence of atherosclerotic lesions on the local fluid dynamics and to correlate the same with subsequent growth of the lesions.

Left ventricular functional improvement after transmyocardial laser revascularization

BACKGROUND

Transmyocardial laser revascularization has been used to treat patients with end-stage coronary artery disease that is not amenable to standard revascularization. Although there is evidence of angina relief and quality of life enhancement, there is little information concerning improvement in myocardial contractility. The purpose of this study was to determine whether transmyocardial laser revascularization improves myocardial function in chronically ischemic myocardium.

METHODS

In a model of chronic ischemia by Ameroid occlusion of the circumflex artery, domestic pigs (n = 8) were treated with transmyocardial laser revascularization. Before laser treatment, segmental contraction was assessed at rest and with dobutamine stress echocardiography. Myocardium subtended by the occlusion was compared with that remote from the occlusion. Six weeks after transmyocardial laser revascularization, the animals were restudied at rest and with stress, and then sacrificed. Sham-treated control animals (n = 4) underwent the same procedures but were not treated with transmyocardial laser revascularization. Control animals did not demonstrate significant recovery of function.

RESULTS

Transmyocardial laser revascularization improved resting function in chronically ischemic myocardium by 100%.

CONCLUSIONS

Transmyocardial laser revascularization significantly improves the function of chronically ischemic myocardium. These data may help explain the mechanisms by which transmyocardial laser revascularization is clinically effective.

Guidelines for the clinical use of electronic mail with patients. The AMIA Internet Working Group, Task Force on Guidelines for the Use of Clinic-Patient Electronic Mail

Guidelines regarding patient-provider electronic mail are presented. The intent is to provide guidance concerning computer-based communications between clinicians and patients within a contractual relationship in which the health-care provider has taken on an explicit measure of responsibility for the client's care. The guidelines address two interrelated aspects: effective interaction between the clinician and patient, and observance of medicolegal prudence. Recommendations for site-specific policy formulation are included.

Use of electronic portal imaging to assess cardiac irradiation in breast radiotherapy

An audit was performed to assess the frequency of cardiac irradiation in patients receiving radiotherapy for left-sided breast cancer. Images from an 'online' electronic portal imaging device were reviewed in patients who were treated with a tangential pair of megavoltage fields. In 169 consecutive patients treated on a Philips SL25 6 MV linear accelerator equipped with an SRI 100 imaging device, the cardiac apex was included in the radiotherapy field in 15 patients (9%). The long term sequelae of such cardiac irradiation is uncertain. The results of this audit suggest that careful treatment technique and quality control with portal imaging can minimize unnecessary cardiac irradiation in the majority of patients.

Human immunodeficiency virus type 1 nucleocapsid protein promotes efficient strand transfer and specific viral DNA synthesis by inhibiting TAR-dependent self-priming from minus-strand strong-stop DNA

During the first strand transfer in reverse transcription, minus-strand strong-stop DNA [(-) SSDNA] is annealed to the 3' end of the acceptor RNA in a reaction mediated by base-pairing between terminal repeat sequences in the RNA and their complement in the DNA. The large stem-loop structure in the repeat region known as TAR could interfere with this annealing reaction. We have developed an in vitro human immunodeficiency virus type 1 (HIV-1) system to investigate the effect of TAR on strand transfer. Mutational analysis demonstrates that the presence of TAR in the donor and acceptor templates inhibits strand transfer and is correlated with extensive synthesis of heterogeneous DNAs formed by self-priming from (-) SSDNA. These DNAs are not precursors to the transfer product. Interestingly, products of self-priming are not detected in HIV-1 endogenous reactions; this suggests that virions contain a component which prevents self-priming. Our results show that the viral nucleocapsid protein (NC), which can destabilize secondary structures, drastically reduces self-priming and dramatically increases the efficiency of strand transfer. In addition, the data suggest that the ability to eliminate self-priming is a general property of NC which is manifested during reverse transcriptase pausing at sites of secondary structure in the template. We conclude that this activity of NC is critical for achieving highly efficient and specific viral DNA synthesis. Our findings raise the possibility that inactivation of NC could provide a new approach for targeting reverse transcription in anti-HIV therapy.

In vitro targeting of antibody-conjugated echogenic liposomes for site-specific ultrasonic image enhancement

Tissue-specific ultrasonic enhancement can be used for the detection and characterization of atherosclerosis. We have previously demonstrated the generation of inherently echogenic (acoustically reflective) liposomes solely by varying lipid composition and controlling the method of production. In this study, echogenic liposomes composed of phosphatidylcholine (PC), 4-(p-maleimidophenyl) butyryl phosphatidylethanolamine (MPB-PE), phosphatidylglycerol (PG), and cholesterol were conjugated to human gamma globulin to determine the effect of antibody conjugation on liposomal acoustic reflectivity. The liposomes remained highly echogenic following antibody conjugation. Echogenic liposomes were also conjugated to rabbit antihuman fibrinogen to study their ability to target fibrin. Antibody-conjugated liposomes were targeted to fibrin-coated filter paper and slides, thrombi made in vitro, and segments of atheroma in an animal model of atherosclerosis. Liposomes were detected by scanning electron microscopy, radiolabeling, and imaging with intravascular ultrasound. Electron microscopy revealed attachment of antibody-conjugated liposomes to fibrin on slides and to the fibrous plaques of the arterial segments, whereas unconjugated liposomes did not attach. Similarly, conjugated liposomes did not attach to normal arteries, indicating their binding to the arterial segment is directed towards a component of the fibrous plaque. Ultrasound imaging of the thrombi demonstrated surface attachment of the acoustic conjugated liposomes. 125I-Labeled liposomes conjugated to rabbit anti-human were targeted to fibrin-coated paper. Counting specifically bound radioactivity showed that > 84% of applied liposomes remained attached to the fibrin after washing with saline. These results demonstrate the potential of acoustically reflective liposomes for site-specific targeting and acoustic enhancement.

Exfoliated malignant cells in glove and instrument washings following head and neck surgery

Loco-regional recurrence following resection of squamous cell carcinoma of the upper aero-digestive tract is a major problem. Cells exfoliated from malignant tumours have been considered capable of implanting and giving rise to local recurrence or metastatic deposits. A prospective study was performed examining washings from the gloves and instruments used in major head and neck operations to determine if exfoliated cells were indeed present. Following removal of the main tumour specimen all surgeons washed their hands in a solution containing a cell fixative and all instruments were soaked in the solution. Samples were then centrifuged and stained using a modified PAP technique. On occasions nuclear fragments consistent with squamous cell carcinoma were present in both glove and instrument washings. We recommend that all surgeons change gloves and instruments following removal of the main tumour specimen and prior to irrigation of the operative field with a tumoricidal agent.

Computation of vascular flow dynamics from intravascular ultrasound images

Analysis of three-dimensional velocity profiles and wall shear stress distribution in a segment of an artery reconstructed from in vivo imaging data are presented in this study. Cross-sectional images of a segment of the abdominal aorta in dogs were obtained using intravascular ultrasound (IVUS) imaging employing a constant pull back technique. Simultaneous measurement of pressures distal and proximal to the vessel segment along with gated pulsed Doppler velocity measurements were also obtained. The three-dimensional geometry of the vascular segment was reconstructed from the IVUS images during peak forward flow phase, and a computational mesh was constructed from the data. A quasi-steady analysis of incompressible Newtonian fluid was performed with a finite difference general purpose computational analysis program FLOW3D. The velocity at the inlet and pressure at the outlet measured at the corresponding time (time referenced to ECG) were used to specify the boundary conditions for the computational flow model. The computed results compared favorably with previously reported results. The purpose of the present study was to analyze the hemodynamics in vascular segments from morphologically realistic three-dimensional reconstructions. The method can be potentially employed in analyzing the hemodynamics in the region of atherosclerotic plaques at various stages of development and the reactivity of the vessel in response to pharmacological and mechanical interventions.

Technical note: the efficacy of megavoltage imaging in the radical radiotherapy of non-small cell lung cancer

Megavoltage imaging (MVI) has been used to obtain digital images of treatment fields during therapy for non-small cell lung cancer. Tumours were seen in all 33 cases studied and in three cases MVI was used to improve the set-up. It is concluded that in the setting of radical radiotherapy for non-small cell lung cancer this is an appropriate technique for the verification and correction of field position and is an aid to quality assurance.

Clinical applications of composite and realtime megavoltage imaging

The versatility of electronic portal imaging devices (EPIDs) is best demonstrated by their ability to perform novel megavoltage imaging protocols, which are still pertinent to good radiotherapy practice. This paper examines two such techniques: composite and realtime imaging. Our EPID can be programmed to acquire and manipulate images very easily, allowing images from segmented treatment protocols to be mixed and displayed, giving a composite image of the effective treatment result. Its use for verifying the efficacy of spinal shielding using a segmented, offset collimator technique is described. By acquiring images very quickly, realtime imaging sequences can be obtained and used to analyse anatomical movement within a single treatment field. The technique is employed here to investigate movement in radical lung, breast, abdomen, pelvis and thyroid treatments. Our results show that the protocol is vital for treatment sites involving the lungs; changes up to 5 mm have been observed in the maximum lung depth for breast treatments, and displacements up to 16 mm for radical lung treatments. It is also useful in other anatomical sites for ensuring that no movement occurs.