bluuebunny/crossref_metadata_2025 huggingface dataset:
H22 Artificial intelligence: whose brains were behind it?
Authors: Long Amy
Published: June 2024

Long considered futuristic, artificial intelligence (AI) has slowly but surely come to prominence in medical spheres over the last 90 years. Dermatology is poised to benefit from emerging AI technologies, with its inherent visual diagnostic methods and the increasing volume of digital photographic data underscoring its suitability for AI-augmented patient care. Algorithms have been around for centuries, but it was Alan Turing who was the first to formalize algorithm and computation in the 1930s, along with cracking the Enigma code during World War II. In 1943, the first artificial neural network of electrical circuits was modelled to simulate biological neurones in the brain, a concept crucial to the success of AI today. The term ‘artificial intelligence’ was first coined by John McCarthy in 1956 at Dartmouth College. Computer-aided diagnosis was first applied in the ana­lysis of pulmonary nodules detected in chest radiographs in 1963. MYCIN, Edward Shortliffe’s doctoral dissertation at Stanford University in the 1970s, was the first powerful use of AI, whereby a computer program correctly identified the causative bacteria in cases of bacteraemia and meningitis and even recommended antibiotic treatments. In 1998 the first Food and Drug Administration (FDA)-approved computer-aided diagnosis system was used in mammography. After the 2010s, a subfield of machine learning called deep learning emerged, and from then on AI flourished, creating meaningful applications across many fields, not least in dermatology. As dermatology is a morphological feature-dependent discipline, machine learning models are increasingly implemented as a diagnostic support tool using image analysis in areas including dermatopathology and skin cancer detection. MelaFind was the first FDA-approved digital cancer detection unit to identify melanoma, succeeded by Nevisense, and recently by DermaSensor, which was approved by the FDA in January 2024. The visual nature of dermatology lends itself well to transformative AI-augmented practice. Although in its infancy, with the correct government and regulation, AI has the potential to help practising dermatologists deliver better skincare.
PS01 (P075) A retrospective review of isotretinoin treatment-related psychosexual health side-effects in a tertiary dermatology clinic
Authors: Mitsaki Kyriaki Stefania , Chawla Sumir , Merika Eirini
Published: June 2024

Isotretinoin is the gold-standard treatment for severe acne. Growing concerns about its association with psychiatric and sexual side-effects have led to the introduction of new monitoring requirements by the Medicines and Healthcare products Regulatory Agency. Herein we present pivotal real-world data on treatment-related psychosexual side-effects. The primary aim of this review was to evaluate mental health outcomes in terms of depressive symptoms and quality of life in patients treated with isotretinoin. Our secondary endpoint was to evaluate the effect of isotretinoin on sexual function. We conducted a retrospective cohort study of 167 consecutive patients who completed treatment with isotretinoin for acne vulgaris between 1 November 2019 and 31 October 2023. Patient Health Questionnaire-9 (PHQ-9) scores, Cardiff Acne Disability Index (CADI) scores and subjective symptom reports were collected at baseline and each follow-up until completion of treatment. We compared data on baseline characteristics, clinical and biochemical side-effects and dosing regimens for patients who met the criteria for moderate or severe depression vs. those with mild or no depressive symptoms. Mean PHQ-9 and CADI scores improved significantly following isotretinoin completion compared with baseline (P < 0.05). Twenty patients (12.0%) met the criteria for moderate or severe depression at baseline. Of these, five patients were on antidepressive therapy and two patients experienced worsening of symptoms on isotretinoin. In total 11 patients (6.5%) met the criteria for moderate or severe depression at the final follow-up; nine of these had reported no or mild depressive symptoms at baseline. Logistic regression analysis did not identify potential risk factors for psychiatric adverse effects with isotretinoin, including no correlation with the average daily or total cumulative dose. We report no cases of suicidal ideation, suicide or erectile dysfunction. A single case of low libido was noted; however, symptoms were mild and did not warrant discontinuation of treatment. The mean follow-up duration after discontinuation of treatment was 209 days. Our analysis did not identify an association of isotretinoin with new-onset depressive symptoms or sexual dysfunction above the background prevalence. The findings support an overall favourable risk profile of isotretinoin at the population level, but the possibility of rare, idiosyncratic adverse events cannot be excluded.
SG03 A case of Bazex–Dupré–Christol syndrome (BDCS)
Authors: Reed Oliver , Schirwani Schaida
Published: June 2024

A 36-year-old man presented to the dermatology department in 2013 with a pink papule on his neck. He had no significant past medical history and took no regular medications. He was born with sparse hair and had milia on his face, neck and ears since childhood. His nonidentical twin daughters were born with milia confined to the head and neck. His mother and maternal aunt had histories of multiple basal cell carcinomas (BCCs), hypotrichosis and follicular atrophoderma and were subsequently diagnosed with Bazex–Dupré–Christol syndrome (BDCS). On examination, he had a superficial BCC on his right posterior neck, with prominent follicular atrophoderma affecting the dorsum of his hands, elbows and feet. He had milia on his ears bilaterally. The BCC was successfully treated with imiquimod 5% cream. The initial genetic testing was uninformative. He was subsequently lost to follow-up but presented again in 2021 with a BCC on his lower eyelid. In 2022 a pertinent paper was published in the British Journal of Dermatology by Liu et al. (Liu Y, Banka S, Huang Y et al. Germline intergenic duplications at Xq26.1 underlie Bazex–Dupré–Christol basal cell carcinoma susceptibility syndrome. Br J Dermatol 2022; 187: 948–61). This revealed new insights into the genetic aetiology for the syndrome, and hence the patient was contacted to consider further genetic testing. Whole-genome sequencing was performed, which identified the same duplications in noncoding sections of chromosome Xq26.1 as highlighted by Liu et al. BDCS is a rare X-linked dominant condition characterized by a triad of BCC, follicular atrophoderma and hypotrichosis. It may also be accompanied by milia, hypohidrosis and trichoepithelioma (AlSabbagh M, Baqi M. Bazex–Dupré–Christol syndrome: review of clinical and molecular aspects. Int J Dermatol 2018; 57: 1102–6). It has been previously thought that there is no single gene solely responsible for BDCS; however, in 2022, Liu et al. suggested that dysregulation of the gene ARHGAP36, resulting from duplications in noncoding sections of chromosome Xq26.1, might be implicated. ARHGAP36 is a flanking centromeric gene near the control hair follicular stem cell compartment (Liu et al.). Our case highlights the importance of considering BDCS as a differential diagnosis in patients presenting with early-onset BCC. Having a confirmed diagnosis enables tailored clinical management with early preventative measures and the opportunity for genetic counselling for future generations of affected individuals.
BT13 (P028) The importance of clinical metadata when triaging patients for face-to-face assessment and possible biopsy in a teledermatology pathway
Authors: Islam Shafiqul , Walls Joseph , Hall Per , Raza Haider , Gan John , Garcia Alba , Wishart Gordon
Published: June 2024

The 7-point checklist (7PCL) is recommended by NICE to select patients with pigmented lesions and possible melanoma for urgent referral. This research investigates the potential of using machine learning (ML) models that utilize patient metadata from a teledermatology pathway including 7PCL for suspicious skin lesion detection, and compares the performance gain for each meta-feature added with the 7PCL. We analysed clinical metadata from 53 601 skin lesions in 25 105 patients who attended private skin cancer diagnosis clinics in the UK between 2015 and 2022. For each lesion, we included the following meta-features: 7PCL (change of lesion size, shape, colour, lesion > 7 mm, inflamed, oozing, itching), weighted 7PCL, Williams score characteristics (patient age, patient sex, natural hair colour, arm mole count, sunburn history, prior nonmelanoma skin cancer), the overall Williams score, prior melanoma, lesion location, lesion age, and whether this was a predominantly nonpigmented pink lesion. All lesions were categorized as suspicious (10%) or nonsuspicious (90%) by skin cancer specialists during telemedicine triage (cancer detection rate = 5%). All meta-features were used as ML model inputs to classify whether each input was associated with suspicious or nonsuspicious classes. This study integrates five ML models (naive Bayes, logistics regression, support vector machine, random forest, and multilayer perceptron) to detect suspicious skin lesions based on patient metadata. Firstly, we compared the ML model performance between the original 7PCL and weighted 7PCL in correctly identifying suspicious skin lesions. We then added each meta-feature with 7PCL and tabulated the performance gain. We utilized balanced accuracy, sensitivity, specificity and area under the curve as evaluation metrics. There were no significant differences observed in model performance between the 7PCL and weighted 7PCL (sensitivity 68.1%). However, the performance of the ML model was improved significantly for each added meta-feature, with the best performance gain (sensitivity 85.2%) observed when 11 meta-features (lesion pink, Williams score, lesion age, sunburn, patient age, Williams group, patient sex, hair colour, site of the lesion on the body, freckling tendency, and mole count) were added to the 7PCL. This research has identified the optimal subset of meta-features that improve ML model performance for categorizing suspicious skin lesions during telemedicine triage, compared with 7PCL alone. Fusing these high-performing meta-features with image modalities is likely to further boost the ML model performance for skin cancer detection, and they could also be used to modify current skin cancer referral guidelines. The study is funded and supported by Innovate UK and the private teledermatology pathway provider.
BT19 The rising dermatology advice and guidance pandemic: building a workforce group with nationally implantable solutions that led to significant improvements over a 10-week period
Authors: Thandi Charankumal Singh , Moss Jake , Andrews Margaret
Published: June 2024

Advice and guidance (A&G) has become more prominent in medicine and has been used across multiple specialties. It has been implemented by most dermatology departments, which tackle the challenge in different ways. Why is it so challenging? What can we do to fix it? How can it be more manageable? These are common questions that are asked by clinicians, managers and referrers. We conducted a multicycle quality improvement project at our hospital collating feedback from clinicians, managers and referrers. As part of this we identified multiple challenges and also had a list of solutions, many of which led to the following improvement. We formed an A&G focus group within the department with a registrar chairing the group and discussing solutions at an annual strategy meeting. The first method was identifying the challenges. The challenges included a high number of referrals, multiple duplicate referrals that were pending, poor-quality photographs including inadequate dermoscopy, and, concerningly, referral of pigmented lesions including melanomas without review within primary care with senior clinicians. Having collated this list of challenges we emailed around asking for each clinician’s feedback from the team that actively takes part in A&G. These responses were collated and are shown below. They led to the following significant improvements in the numbers of pending A&G dermatology cases in the hospital. Over a 10-week period during this project there was a 33.6% reduction in the number of pending referrals from a peak of 1075 cases. There was a 99.4% reduction in the number of days taken to respond to urgent cases, a 35.7% reduction in the number of days taken to respond to paediatric cases and a 83.3% reduction in the number of days taken to respond to adult A&G referrals. The solutions involved (i) ensuring A&G staff were given clear dedicated time within job plans, with each clinician having a set number of cases to do per month; and (ii) feeding back response times via the local integrated care board during meetings and signposting to correct referral pathways during responses (as a tool to reduce overall duplication). Future plans include holding a circuit breaker week and sending out generic criteria for advice and guidance at the end of each response, highlighting current response time and the avoidance of 2-week-wait lesions. Our model can be used nationally within any medical or surgical specialty and has the potential to lead to significant improvements. It can help to ensure that referrers are clear of the pathways, while making A&G more manageable.
BT32 Teledermatology service evaluation compared with standard face-to-face review for 2-week-wait skin cancer referrals
Authors: Byrne Niamh , Wong Charlotte , Khoo Andre
Published: June 2024

Teledermatology has been shown to be accurate in the diagnosis of skin cancer. The number of skin cancer referrals to secondary care has surged and dermatology departments are under increasing pressure to meet cancer pathway targets. The aim of this study was to compare service outcomes for teledermatology vs. conventional face-to-face review. We performed a retrospective review of adult patients referred by general practitioners for suspected skin cancer via the 2-week-wait pathway from August 2022 to February 2023. Patients were assessed either by conventional face-to-face appointment or via teledermatology. Teledermatology patients completed a questionnaire and were seen by a photographer in the community who took regional, macroscopic and dermoscopic images. The primary outcomes were times from referral to first clinical appointment and to surgery (if applicable), surgical intervention rate, and histological diagnoses (if applicable). Statistical analysis was performed using Prism software (GraphPad Software, La Jolla, CA, USA). Comparisons between groups were performed with the Mann–Whitney U-test and Fisher exact, as appropriate. P-values < 0.05 were considered statistically significant. In total, 50 consecutive patients assessed by a single clinician via teledermatology were compared with 100 randomly selected patients assessed by the same clinician via face-to-face review. More than half of patients were female in both groups (52% teledermatology vs. 58% face-to-face). The teledermatology group was older ,with a mean age of 56.7 years (SD 18.5) vs. 40 years (SD 20.5), P < 0.001. The median waiting time for a clinical appointment was slightly longer in the teledermatology group [16.5 days (SD 8.5) vs. 14 days (SD 5.4) for face to face (P < 0.001)]. The median waiting time from receipt of referral to surgery was similar in both groups [38 days (SD 17.3) for teledermatology vs. 32 days (SD 12.5) for face to face (P = 0.4)]. The median waiting time from decision to treat to surgery was similar in both groups [21 days (SD 17.3) for teledermatology vs. 20 days (SD 11.7) for face to face (P = 0.9)]. There was no significant difference in the diagnostic biopsy/therapeutic excision rate (34% for teledermatology vs. 27% for face to face, P = 0.37), or in the proportion of benign, dysplastic and malignant lesions biopsied or excised (P = 0.75). Over one-third of patients reviewed by teledermatology were discharged without the need to attend hospital. In conclusion, this model of teledermatology offers a robust way to assess suspected cancer, with biopsy rates and eventual diagnoses comparable with conventional models. The use of professional medical photography may delay initial review, but higher-quality images are associated with improved diagnostic accuracy.
BT35 Quality improvement project: modernizing the inpatient dermatology handover
Authors: Shah Rishi , Whitehead Jenny , Ramoutar Amrika
Published: June 2024

Dermatology is unique in our region because it provides on-call services to multiple sites and different National Health Service (NHS) trusts locally. This presents a number of challenges as different NHS trusts utilize different information technology and procedural systems. This quality improvement project (QIP) aimed to find a solution to the problem of having an effective and efficient handover system for inpatients across different trusts. Prior to this QIP, the handover consisted of an email that was sent at the end of each day summarizing the inpatient cohort. This had several issues including missing details, delayed updates and not updating all of the relevant staff. The initial Plan Do Study Act (PDSA) cycle surveyed the clinical staff to assess whether there was a problem with the current handover and potential solutions that could be considered. The results showed that the team were dissatisfied with the current handover and the majority utilized the on-call service to find out about the inpatients. Of the available solutions, the majority of staff wanted to explore an online solution via Microsoft Teams. The main challenge with the proposed handover on Teams was maintaining patient confidentiality given the sensitivity of the data being held. This was reviewed with the clinical governance team and a data protection impact assessment was carried out and approved. A Teams group and handover file were then created. The feedback highlighted that the handover template needed optimization, resulting in a second PDSA cycle. Senior colleagues approved a suitable template that was then trialled on the Teams group for handover. The survey results showed a significant improvement in the content, accessibility, usability and means of handover. The main issue identified was that some staff did not know how to access the Teams group to view the handover. This was remedied with the creation of a standard operating procedure, which provided instructions on how to access and use the new handover. This QIP with two PDSA cycles provided a number of advantages such as the ability of the handover to be accessible to a predefined group of people from any site or trust, and that it can be updated in real time. It can also be utilized and updated during virtual board rounds. Most importantly, this change has created an effective and efficient means of handover, as is reflected in the results of the postintervention survey.
BT39 Teledermatology assessment of community skin lesion referrals: insights, challenges and recommendations
Authors: Nguyen Vivienne , Jones Ruth , Gupta Girish
Published: June 2024

Consultations for skin lesions rank are a very common reason for general practitioner (GP) visits, with the urgent suspicion of cancer (USOC) referral pathway directing potentially cancerous lesions to dermatologists in our region. Despite the valuable role of clinical photographs alongside referrals, the variable quality poses a significant challenge. From March to April 2023, 100 GP referrals containing photos in our USOC pathway underwent analysis by two independent consultant dermatologists. They provided their top three diagnoses with free-text comments on image quality. Notably, prevalent image comments included ‘out of focus (60%)’ and ‘poor illumination’ (55%). Dermoscopy images were included in 15 community photos. Consultant 1 (G.G.) identified seborrhoeic keratosis as the primary diagnosis in 32%, while consultant 2 (R.J.) noted it as the top diagnosis in 34%. Consultant 1 included the GP’s diagnosis in their top three differentials 40% of the time, while consultant 2 did so 30% of the time. Existing guidance on teledermatology image quality is limited but emphasizes clear, well-lit photos with proper focus, taken from various angles and distances. Despite this, our data reveal a noticeable deviation from these practices. We propose that possible contributory factors leading to poor-quality images include time constraints during GP consultations, lack of awareness regarding guidance, and the use of devices with suboptimal image resolution. Notably, there are no local specific guidelines for community photos in our area. Based on our findings, we have created a local guideline, emphasizing the need for clear, focused images where the lesion is centrally framed, utilizing natural sunlight ideally at an angle to highlight skin texture. Additionally, an enlarged photo is recommended, balancing size with the maintenance of focus on the area of interest. Teledermatology provides broader access to expert advice, facilitates timely consultations, improves efficiency, and encourages global collaboration. However, the heterogeneity in photos can lead to misdiagnosis, inappropriate triage, and inefficient resource allocation. The implementation of guidance for referral photos can optimize resource use, enhance patient satisfaction, and streamline workflow.
Duty of candour and clinically significant accidental or unintended exposures: revisiting the definition of moderate harm for patient safety incidents involving ionizing radiation
Authors: Kotre C John
Published: June 2024

Objective

To explore a quantitative interpretation of the term ‘moderate harm’ as applied to the triggering of the duty of candour associated with clinically significant accidental and unintended exposures to ionizing radiation.

Methods

Current definitions of ‘moderate harm’ were matched to the lay descriptions of disease and injury states used in the calculation of detriment as disability-adjusted life years (DALY) by the World Health Organization, to obtain a value of detriment associated with ‘moderate harm’. Published conversion factors between effective dose and DALY were used to calculate the effective dose associated with the same detriment.

Results

The DALY loss associated with a moderate harm incident is estimated as 0.0216 years. This corresponds to the detriment resulting from exposure to ionizing radiation of 21 mSv. An effective dose of 21 mSv relates to a probability of induced cancer of 0.0012.

Conclusion

The results obtained closely match existing guidance although the method used is completely different. It is concluded that there is no evidence to change the existing guidance on the triggering of DoC in radiation incidents.

Advances in knowledge

An alternative approach to linking ‘moderate harm’ and radiation detriment has reinforced existing guidance.
Techno–economic analysis of green hydrogen production by a floating solar photovoltaic system for industrial decarbonization
Authors: Muthia Rahma , Pramudya Anastasia Segari Putri , Maulana Mochamad Rafly , Purwanto Widodo Wahyu
Published: June 2024

This study proposes a conceptual design of green hydrogen production via proton exchange membrane electrolysis powered by a floating solar photovoltaic system. The system contributes to industrial decarbonization in which hydrogen blending with natural gas is proposed as an approach to smooth the energy transition. The proposed design addresses the challenge of supplying a continuous flow-rate of green hydrogen, which is typically demanded by industrial end users. This study particularly considers a realistic area required for the installation of a floating solar photovoltaic system. To enable the green hydrogen production of 7.5 million standard cubic feet per day, the required structure includes the floating solar photovoltaic system and Li-ion batteries with the nominal capacities of 518.4 megawatts and 780.8 megawatt-hours. This is equivalent to the requirement for 1 524 765 photovoltaic modules and 3718 Li-ion batteries. The assessment confirms the technical viability of the proposed concept of green hydrogen production, transportation and blending. While the present commercialization is hindered by economics due to a high green hydrogen production cost of USD 26.95 per kg, this green hydrogen pathway is expected to be competitive with grey hydrogen produced via coal gasification and via natural gas steam reforming by 2043 and 2047, respectively.
Quantification of myocardial blood flow using dynamic myocardial perfusion computed tomography
Authors: Gutierrez Guadarrama D , Rangel Calzada A , Vallejo E
Published: June 2024

Background

Cardiac CT angiography (CCTA) remains a limited method for evaluating the physiologic significance of coronary stenosis. On the other hand, dynamic techniques for evaluating myocardial perfusion imaging (MPI) allow quantification of myocardial blood flow (MBF) which may improve identification of hemodynamically relevance of luminal stenosis.

Objective

the purpose of this study was to determine the feasibility of vasodilator-stress CT-based dynamic MPI (CT-dMPI) for regional and global quantitively measurements of MBF for the identification of hemodynamically significant coronary stenosis.

Materials and methods

CCTA and CT-dMPI of 43 patients with chest pain were evaluated for the presence of coronary stenosis associated with perfusion defects and abnormal values of MBF (34 men and nine women; mean age, 60.9±12.9 years). Global MBF was quantified according to CT-dMPI and MBF values of normal and abnormal per-vessel territory (LAD, LCx and RCA) were correlated to the presence or not of coronary artery stenosis at CCTA. The relative MBF (rMBF) was calculated per vessel territory as the maximum coronary MBF divided by the reference MBF.

Results

In subjects without coronary plaques (Group I) the mean value of global MBF was 117.7±19.4 mL/100 mL/ml; LAD maximum blood flow was 130.9±9.7 mL/100 mL/ml; LCx maximum blood flow was 123.1±10.7 mL/100 mL/ml; RCA maximum blood flow was 128.1±7.3 mL/100 mL/ml; In patients without anatomically significant coronary stenosis or perfusion defects (Group II, 1%-69%) the mean value of global MBF was 127.5±26.2 mL/100 mL/ml; LAD maximum blood flow was 145.7±8.27 mL/100 mL/ml; LCx maximum blood flow was 134.5±8.1 mL/100 mL/ml; RCA maximum blood flow was 144.8±78.9 mL/100 mL/ml; In patients with significant stenosis (>70%) the mean value of global MBF was 104.2±25.2 mL/100 mL/ml; LAD maximum blood flow was 110.4±7 mL/100 mL/ml; LCx maximum blood flow was 80.1±6.8 mL/100 mL/ml; RCA maximum blood flow was 92.7±5.9 mL/100 mL/ml; The median relative MBF was 0.73 for Group III and 0.93 for Group I and II. CT-dMPI demonstrated a sensitivity, specificity, PPV, NPV, and accuracy for the detection of significant stenosis of >70% (Group III) 82%, 100%, 100% and, 94%.

Conclusions

vasodilator-stress CT-based dynamic MPI (CT-dMPI) for regional and global quantitively measurements of MBF is feasible and the findings correlate with the visual assessment of the presence of coronary artery stenosis at CCTA. CT-dMPI might improve the diagnostic accuracy for identifying flow-obstructing stenosis compared with CCTA alone.
Calcium density of the aortic valve: a comparison of its measurement between echocardiography and computed tomography in a cohort of South American patients with severe aortic stenosis
Authors: Guaman-Valdivieso C G , Lluberas N , Aramburu J , Parma G , Lluberas S , Lluberas R
Published: June 2024

Background/Introduction

The baseline calcium load of the valve is indicative of aortic stenosis progression. While echocardiography remains the standard study for severity assessment, with acknowledged limitations, computed tomography excels in its remarkable reproducibility in measurements, particularly through the calculation of the valve calcium score. The indexing of valve calcium to the area of the aortic ring, termed the calcium density of the aortic valve, has been proposed as an additional diagnostic and prognostic variable. In Asian populations, the diagnostic precision of the calcium score threshold is lower, suggesting that valve area density might be a more suitable reference. Local-level research on this variable is warranted.

Purpose

Correlate the measurement of aortic valve area density performed by computed tomography with that calculated using echocardiographic variables. Analyse whether the density of the aortic valve area has prognostic value concerning the presence of paravalvular leak one month after transcatheter aortic valve implantation (TAVI).

Methods

Analytical retrospective cohort study with prospective follow-up aimed at correlating the measurement of aortic valve area density performed by computed tomography with that calculated using echocardiographic variables and assessing its prognostic value. The registry was conducted at two centres. All patients with symptomatic severe aortic stenosis who underwent TAVI from June 2021 to June 2023 were included. The ethical guidelines were followed, respecting the anonymity of the data and the Declaration of Helsinki. Statistical analyses were performed using SPSS V.25, with a P value less than 0.05 considered significant.

Results

Sixty-three patients were included, 47.61% of whom were female, with a mean age of 82 years (Q1-Q3: 79; 86 years). A statistically significant correlation was found when assessing the density of the aortic ring area estimated from echocardiography compared to that estimated from computed tomography (Figure 1). In the examination of the ROC curves for the calcium score and the aortic valve calcium density, they were identified as poor predictors for paravalvular leak outcomes (Figure 2).

Conclusions

A correlation is observed between the density of the aortic valve area measured by computed tomography and that calculated with echocardiographic variables. However, they do not appear to hold prognostic value regarding the presence of a paravalvular leak one month after the TAVI procedure.
Improvement of myocardial perfusion SPECT studies with a cardio-dedicated CZT gamma camera. Comparison with an analogical SPECT/CT gamma camera
Authors: Aguade-Bruix S , Cardozo-Saavedra A , Palomar Munoz A , Aguirre E , Romero-Farina G , Cuellar-Calabria H , Pizzi M N , Roque A
Published: June 2024

Aim

To show the improvement in myocardial perfusion SPECT studies achieved in the year 2023 using a cardio-dedicated CZT gamma camera, compared to year 2021 when using an analogical SPECT/CT gamma camera.

Methods

We have collected data on nuclear cardiology care activity for the years 2021, 2022 and 2023, including patients treated in our institution. In 2021 myocardial perfusion imaging (MPI) studies were performed primarily on an analogical SPECT/CT gamma camera, which was replaced by a cardio-dedicated CZT in 2022. In 2023 MPI was carried out mainly in the new CZT gamma camera. For comparison we have selected the SPECT MPI studies performed in 2021 (one day protocol mainly with 18 + 12 minutes acquisition plus 10 minutes for in-out patient), and 2023 MPI studies (one day protocol mainly with 6 + 4 minutes acquisition plus 10 minutes for in-out patient).

Results

(Results Table) With the new CZT cardio-dedicated gamma camera, the number of stress SPECT increased by 442 (31%) and rest SPECT by 341 (23%), with a total annual increase of 783 SPECT studies (27%) in 2023 compared to 2021. Furthermore, the complexity of SPECT studies has increased in 2023, since part of the studies carried out (68) correspond to SPECT studies of myocardial blood flow, which are obtained in the same gamma camera simultaneously. In addition, the gamma camera acquisition time has reduced by 66% (from 30 to 10 minutes), and the patient total time has reduced by half (from 40 to 20 minutes). Counts in the cardiac area have increased on average more than 1000 times (14 million counts for a low dose study and 32 million for a high dose study).

Conclusions

The improvement achieved in SPECT studies for myocardial perfusion after upgrading to a cardio-dedicated CZT gamma camera has been an annual increase of 27% in number of SPECT studies, and a decrease in patient total time by half, which has allowed implementing more complex studies, such as evaluation of myocardial blood flow.
Cut-off values of myocardial blood flow using cardiac-dedicated CZT SPECT
Authors: Aguade-Bruix S , Cardozo Saavedra A , Aguirre E , Palomar Munoz A , Gamez Cenzano C , Ferreira Gonzalez I , Escobar Amores M , Herance Camacho R , Cuellar-Calabria H , Pizzi M N , Roque A , Romero-Farina G
Published: June 2024

Background

While not the primary mechanism or hallmark for the pathogenesis of all myocardial disease, coronary microvascular disease is acknowledged to play a crucial role in the diagnostic and prognosis of different diseases. PET is considered the non-invasive gold standard for evaluating myocardial blood flow, but SPECT-CZT cameras have become a promising and comparable tool for this purpose, more widespread in some countries. However, each SPECT-CZT trademark possesses different characteristics and each service adopts different protocols. This requires establishing specific cut-off values for our recently installed CZT SPECT camera.

Purpose

The aim of this study is to determine cut-off values of myocardial blood flow (MBF) using a cardiac-dedicated CZT SPECT in our population.

Methods

We prospectively analyzed 109 patients who underwent gated-SPECT using a cardiac-dedicated CZT SPECT. Of these, 43 (39.4%) subjects correspond to a control group (with normal myocardial perfusion in rest and stress, normal gated, normal coronary CT, without myocardial hypertrophy, diabetes or valvular heart disease, all subjects asymptomatic and in sinus rhythm) and 66 (60.6%) patients correspond to a pathological group (angina:10, diabetes: 23, dyspnea: 7, heart failure: 3, non-fatal myocardial infarction: 14, left ventricular ejection fraction <50%: 9, coronary artery disease: 14, coronary revascularization: 9, valvular heart disease: 8). The cut-off values for MBF at rest (MBF-rest), MBF during stress or hyperemic phase (MBF-stress), MBF reserve (MBF-reserve: defined as MBF-stress/MBF-rest), and MBF differences (MBF-differences: MBF-stress - MBF-rest) were investigated. Statistical analyses were performed with Receiver Operating Characteristics (ROC) curve analysis using STATA 18. StataCorp, College Station, TX, USA.

Results

In order to differentiate control group and pathological group, cut-off values were (Results Table):

Conclusions

Different cut-off values of MBF were observed between subjects and patients using a cardiac-dedicated CZT SPECT camera.Results Table
Comparison between myocardial perfusion SPECT and cardiac magnetic resonance findings in non-ischemic dilated cardiomyopathy
Authors: Nunes R , Martins E , Dias P
Published: June 2024

Background

Dilated cardiomyopathy (DCM) is defined as the presence of left ventricular or biventricular dilatation and systolic dysfunction in the absence of abnormal loading conditions or significant coronary heart disease. The diagnostic work-up for patients with DCM includes cardiac imaging and cardiac magnetic resonance (CMR) is the gold-standard method for detailed morphological caracterization. Although there is a limited diagnostic role for radionuclide imaging in DCM, myocardial perfusion single-photon emission computed tomography (SPECT) is commonly performed to exclude ischemic etiology.

Purpose

The aim of this study was to compare the findings of myocardial perfusion SPECT (MPS) and CMR in non-ischemic DCM.

Methods

We included 35 patients that had been diagnosed with DCM and underwent MPS and CMR for etiological diagnosis in our institution between January 2020 and December 2023. We evaluated left ventricular motility, thickening and perfusion defects in MPS, the presence of late gadolinium enhancement (LGE) in CMR and the values of left ventricular ejection fraction (LVEF), end-systolic and end-diastolic volumes in both exams.

Results

24 patients were male (69%), with a median age of 65,9 ± 11,8 years. Ischemic etiology for DCM was excluded based on CMR in 25 patients, 6 patients were diagnosed with alcoholic DCM, 3 patients with familial DCM and 1 with chemotherapy-induced cardiotoxicity. In 23 patients (66%), MPS showed diffuse motility and thickening abnormalities. In MPS, 34 patients (97%) had perfusion defects and 17 (50%) had reversible defects. 14 patients (41%) had only one perfusion defect while 20 (59%) patients had 2 or more. The septal wall was the most affected (24 patients - 69%). In 24 patients (69%), CMR showed LGE suggestive of fibrosis and in 88% of these patients the fibrosis was seen in the septal wall. A moderate correlation (0,508) was found between LVEF in MPS and CMR. 8 patients (33%) presented LGE in CMR and had non-reversible perfusion defects in the same myocardial wall in MPS while 12 patients (50%) presented with reversible perfusion defects in the same LGE location. Of the 12 patients that presented with LGE in CMR and reversible defects in MPS, 7 (58%) had total or parcial but significant reversibility and 5 (42%) had partial but non-significant reversibility.

Conclusions

The presence of perfusion defects is common in non-ischemic DCM. In most patients the perfusion defects (MPS) and fibrosis (CMR) were seen in the septal wall. Reversible defects may be explained by microvascular dysfunction known to play a role in DCM pathogenesis. These findings should be taken into account in the interpretation of MPS results in the etiological diagnosis of DCM.
CZT SPECT regional myocardial flow reserve: can it enhance risk stratification?
Authors: Mesquita C , Palazzo I , Pacheco J , Ker W , Sabra M M M , Correa N L , Chambi A
Published: June 2024

Background

Numerous studies indicate that patients with diminished capacity for maximal hyperemia face an unfavorable cardiovascular prognosis. The presence of compromised coronary flow reserve is linked to a higher incidence of adverse cardiovascular outcomes (1). SPECT equipment featuring high-performance CZT detectors has been utilized for the quantitative evaluation of coronary flow at rest and during maximal hyperemia. Incorporating Myocardial Flow Reserve (MFR) into SPECT MPI for CAD screening using CZT SPECT may aid in identifying high-risk patients. In one study utilizing CZT SPECT, all regions with a regional CZT MFR ≤ 1.8 exhibited an invasive CFR < 2 (2). The clinical utility of regional CZT-derived MFR data is still under evaluation but could assist in risk stratification.

Objective

To describe the frequency of abnormal MFR in patients referred for CZT SPECT and determine if regional MFR data could contribute to risk stratification in this context.

Methodology: One hundred consecutive patients with suspected CAD or known CAD were referred for CZT SPECT between October 7th, 2021, and December 30th, 2022. Patients underwent pharmacological stress myocardial perfusion scintigraphy and rest imaging using a D-SPECT device (Spectrum Dynamics) with dynamic tomographic image acquisition (dynamic SPECT) following administration of 99mTc-sestamibi via an injection pump (Bracco) at a flow rate of 1 ml/second. The dynamic tomographic images were analyzed using Cedars Sinai's QPS kinetic ® software to calculate MFR. MFR values < 2, either regional or global, were considered abnormal. Statistical analysis employed a significance level of 5% and included the Chi-square and Fisher exact test.

Results

We evaluated 100 patients (15 men) with a mean age of 71.4 years. Of these 100 exams: 13 exhibited MFR < 2.0 (Group A); 51 had MFR between 2.0 and 3.0 (Group B); and 36 had MFR > 3.0 (Group C). In Group B, 14 patients displayed MFR in any of the 3 coronary territories below 2.0 (27%). Group C had no patients with reduced regional MFR. Myocardial ischemia was more prevalent in patients in Group A compared to Group B (54% vs. 19%; p = 0.01) and in Group B compared to Group C (19% vs. 3%; p = 0.02). Patients with regional MFR < 2.0 in Group B exhibited a higher incidence of myocardial ischemia compared to patients in Group B with normal regional MFR (35% vs. 10%; p = 0.02).

Conclusion

A decreased regional MFR as measured by CZT SPECT is observed in one out of four patients with MFR between 2.0 and 3.0; and is associated with an increased prevalence of myocardial ischemia. These findings suggest a potential additional benefit in risk stratification that may be derived from regional quantitative blood flow assessment with CZT SPECT.
Regional left ventricle involvement in cardiac transthyretin amyloidosis in SPECT/CT with [99mTc]Tc-DPD
Authors: Holcman K , Rubis P , Stepien A , Graczyk K , Mroz K , Szot W , Dziewicka E , Podolec P , Kostkiewicz M
Published: June 2024

Background

Transthyretin amyloid (ATTR) cardiomyopathy is now more frequently diagnosed, partly due to advances in scintigraphic imaging and introduction of non-invasive diagnostic algorithms. Application of hybrid technique single-photon emission computed tomography and computed tomography (SPECT/CT) provides greater anatomic resolution, enabling the assessment of regional cardiac involvement.

Purpose

The aim of this prospective study was assessment of left ventricle involvement in patients with ATTR in SPECT/CT with [99mTc]Tc 3,3-disphono-1,2-propanodicarboxylic acid (DPD).

Methods

We present data based on evaluation of 100 patients, index patients with ATTR (group 1) and first-degree relatives (group 2) who were studied between June 2020 and December 2023. Study protocol included clinical data, free light chain blood immunoglobulins and urine immunofixation, transthoracic echocardiography (TTE) with global longitudinal strain (GLS) analysis, planar whole body acquisition and SPECT/CT with [99mTc]Tc-DPD, genetic testing by an amplicon-based next-generation TTR sequencing approach, and in selected cases cardiac or soft tissue biopsy.

Results

Study was conducted as multimodality and genetic cascade screening for relatives of individuals with ATTR. The population included hereditary ATTR (ATTRm) and ATTR wild type (ATTRwt). There were detected following types of TTR variants - Phe53Leu, Ala101Val, Glu112Lys, Glu109Lys, Glu122Lys, Glu82Lys. Overall, none of ATTRwt relatives expressed increased tracer uptake in scintigraphy. Overall, 26% first-degree relatives were diagnosed with pathogenic TTR variant and 7% had positive SPECT/CT with [99mTc]Tc-DPD. Importantly, among patients with positive SPECT/CT with [99mTc]Tc-DPD 58% presented asymmetrical left ventricle uptake. Overall, there were no differences in terms of radiotracer distribution between ATTRwt and ATTRm groups (p=0.85).

Conclusions

Regional left ventricle involvement in cardiac transthyretin amyloidosis can be assessed in SPECT/CT with [99mTc]Tc-DPD. The majority of patients present asymmetric cardiac uptake of radiotracer, both in the ATTRm and ATTRwt groups. Assessment of regional left ventricle involvement in cardiac transthyretin amyloidosis in SPECT/CT may in future translate into further enhancement of disease evaluation and improving prognosis in the group of patients.
Myocardial flow reserve recovery in patients with Takotsubo syndrome: insights from positron emission tomography
Authors: Kadoya Y , Chong A , Small G , Chow B , Dekemp R , Ruddy T , Beanlands R , Crean A
Published: June 2024

Background

Coronary microvascular dysfunction (CMD) has been implicated in the pathogenesis of Takotsubo syndrome (TTS). Positron emission tomography (PET) plays a key role in the assessment of CMD through myocardial flow reserve (MFR). However, there is limited information on the temporal progression of MFR and its relationship to coronary artery disease (CAD) in TTS patients.

Methods

This study evaluated patients with TTS who underwent cardiac catheterization and PET within one year of hospitalization. Patients were categorized into acute (≤10 days), subacute (11-30 days), and chronic (≥31 days) stages based on post-onset time of PET assessment. MFR comparisons between stages, prevalence of abnormal MFR (<2.0), and MFR changes with or without obstructive CAD (≥70% stenosis as per coronary angiography) were analyzed.

Results

Of the 88 patients studied (mean age 70; 96% female), 52 (59%) were in the acute, 17 (19%) in the subacute, and 19 (22%) in the chronic stage. Median MFR in the acute stage was 2.0 (1.5-2.3), with 58% of patients showing abnormal MFR. A significant time-dependent improvement in MFR was observed (p=0.002) (Figure A), accompanied by a decreased prevalence of abnormal MFR. Patients with obstructive CAD in the acute stage had a significantly lower MFR compared to patients without CAD (1.81 vs. 2.15, p=0.027), while no MFR improvement was observed in the subacute and chronic stages (p=0.346) (Figure B).

Conclusions

PET-derived MFR was impaired in TTS patients during the acute phase, with improvement suggesting potential recovery from CMD over time. The concurrent presence of obstructive CAD might impede this recovery process.  Figure B
Prognostic value of motion corrected cardiac PET images with normal interpretation
Authors: Oldfield C , Armstrong I , Arumugam P
Published: June 2024

Background

Patient motion during rest-stress vasodilator rubidium-82 myocardial perfusion PET remains a challenge and can affect relative images interpretation when severe. Current commercial solutions are limited to frame-by-frame correction of dynamic images for blood flow assessment. The correction of time-averaged static images remains a challenge. Our department has previously published work on the severity and prevalence of motion degradation of static relative perfusion images and demonstrated the usefulness of a prototype Data-Driven Motion Correction (DDMC) algorithm. We are evaluating this software in patients with evidence of motion on dynamic images and there is artefact suggestive of motion affecting relative perfusion images.

Purpose

The purpose of this work was to look at clinical follow up (hospital admission due to chest pain, MI or all cause death) of cases where DDMC static images were interpreted as normal.

Method

We retrospectively identified all patient between April 2018 and December 2020 that were referred for clinically indicated myocardial perfusion using rubidium-82. All patients’ images were acquired on a Siemens Biograph Vision 600 following administration of 20 mCi of Rb-82. A three-year follow-up of MACE and admission records for all patients.

Results

We identified 128 patients (54F: 57.5±9.3yr; 74M: 62.1±9.0yr) where DDMC was used to correct for significant motion blurring of the static relative perfusion images. Of these, 87 patients (46F,41M) were reported as normal. Follow-up showed no MACE, admission or all-cause death in all female patients. In the male patients, two were admitted for troponin-negative chest pain and there were five deaths, but none were cardiac-related.

Conclusion

This work demonstrates the usefulness of the DDMC for static motion correction in salvaging and improving image quality while continuing to provide reliable prognostic information for images interpreted as normal.