The Use of Virtual Tissue Constructs That Include Morphological Variability to Assess the Potential of Electrical Impedance Spectroscopy to Differentiate between Thyroid and Parathyroid Tissues during Surgery.

Electrical impedance spectroscopy (EIS) has been proposed as a promising noninvasive method to differentiate healthy thyroid from parathyroid tissues during thyroidectomy. However, previously reported similarities in the in vivo measured spectra of these tissues during a pilot study suggest that this separation may not be straightforward. We utilise computational modelling as a method to elucidate the distinguishing characteristics in the EIS signal and explore the features of the tissue that contribute to the observed electrical behaviour. Firstly, multiscale finite element models (or 'virtual tissue constructs') of thyroid and parathyroid tissues were developed and verified against in vivo tissue measurements. A global sensitivity analysis was performed to investigate the impact of physiological micro-, meso- and macroscale tissue morphological features of both tissue types on the computed macroscale EIS spectra and explore the separability of the two tissue types. Our results suggest that the presence of a surface fascia layer could obstruct tissue differentiation, but an analysis of the separability of simulated spectra without the surface fascia layer suggests that differentiation of the two tissue types should be possible if this layer is completely removed by the surgeon. Comprehensive in vivo measurements are required to fully determine the potential for EIS as a method in distinguishing between thyroid and parathyroid tissues.

Near-infrared fluorescent imaging for parathyroid identification and/or preservation in surgery for primary hyperparathyroidism.

Introduction: Near infrared autofluorescence (NIRAF) is a novel intraoperative technology that has shown promising results in the localisation of parathyroid glands (PGs) over the last decade. This study aimed to assess the potential utility of NIRAF in first time surgery for primary hyperparathyroidism (PHPT). Methods: An observational study over a period of 3 years in patients who underwent surgery for PHPT was designed. Data on the use of NIRAF and fluorescent patterns in different organs (thyroid and parathyroid) and parathyroid pathology (single versus multi-gland disease) were explored. In addition, cure rates and operating times were compared between the NIRAF and no-NIRAF groups to determine the potential value of NIRAF in this cohort. Results: In 230 patients undergoing first time surgery for PHPT, NIRAF was used in 50 patients. Of these 50 patients, NIRAF was considered to aid parathyroid identification in 9 patients (18%). The overall cure rate at 6 months of follow-up was 96.5% (98% in NIRAF and 96.1% without NIRAF; p=1.0). The median (interquartile range) operating time was longer in the NIRAF arm at 102 minutes (74-120 minutes) compared to the no-NIRAF arm at 75 minutes (75-109 minutes); however, this difference was not statistically significant (p=0.542). Although the median parathyroid to thyroid (P/T) auto-fluorescence (AF) ratio was similar between single gland and multi gland disease (2.5 vs to 2.76; p=1.0), the P/T AF ratio correlated negatively with increasing gland weight (p=0.038). Conclusion: The use of NIRAF resulted in some potential "surgeon-perceived" benefit but did not lead to improvements in cure rates. The negative correlation between fluorescent intensity and gland weight suggests loss of fluorescence with pathology, which needs further investigation. Further studies on larger cohorts of patients, in depth analysis of fluorescence patterns between normal, adenomatous, and hyperplastic glands and evaluation of user experience are needed. Primary hyperparathyroidism, hyperparathyroidism, autofluorescence, near-infrared fluorescence, parathyroid glands, endocrine, surgery.

Evaluating the performance of artificial intelligence software for lung nodule detection on chest radiographs in a retrospective real-world UK population.

OBJECTIVES: Early identification of lung cancer on chest radiographs improves patient outcomes. Artificial intelligence (AI) tools may increase diagnostic accuracy and streamline this pathway. This study evaluated the performance of commercially available AI-based software trained to identify cancerous lung nodules on chest radiographs. DESIGN: This retrospective study included primary care chest radiographs acquired in a UK centre. The software evaluated each radiograph independently and outputs were compared with two reference standards: (1) the radiologist report and (2) the diagnosis of cancer by multidisciplinary team decision. Failure analysis was performed by interrogating the software marker locations on radiographs. PARTICIPANTS: 5722 consecutive chest radiographs were included from 5592 patients (median age 59 years, 53.8% women, 1.6% prevalence of cancer). RESULTS: Compared with radiologist reports for nodule detection, the software demonstrated sensitivity 54.5% (95% CI 44.2% to 64.4%), specificity 83.2% (82.2% to 84.1%), positive predictive value (PPV) 5.5% (4.6% to 6.6%) and negative predictive value (NPV) 99.0% (98.8% to 99.2%). Compared with cancer diagnosis, the software demonstrated sensitivity 60.9% (50.1% to 70.9%), specificity 83.3% (82.3% to 84.2%), PPV 5.6% (4.8% to 6.6%) and NPV 99.2% (99.0% to 99.4%). Normal or variant anatomy was misidentified as an abnormality in 69.9% of the 943 false positive cases. CONCLUSIONS: The software demonstrated considerable underperformance in this real-world patient cohort. Failure analysis suggested a lack of generalisability in the training and testing datasets as a potential factor. The low PPV carries the risk of over-investigation and limits the translation of the software to clinical practice. Our findings highlight the importance of training and testing software in representative datasets, with broader implications for the implementation of AI tools in imaging.

Findings of pilot study following the implementation of point of care intraoperative PTH assay using whole blood during surgery for primary hyperparathyroidism.

Objective: To report findings of pilot study using a novel point of care (POC) intraoperative parathyroid hormone (IOPTH) assay for parathyroid hormone (PTH) using whole blood during surgery for primary hyperparathyroidism (PHPT). Methods: Patients undergoing surgery for primary hyperparathyroidism from March to November 2022 where intraoperative PTH assay was performed using the NBCL CONNECT IOPTH and the laboratory PTH assay were included (group 1). The biochemistry results were reviewed to determine concordance between NBCL and lab PTH values and diagnostic test parameters of the NBCL CONNECT assay. 'In-theatre' times were then compared with a historical cohort (group 2) where the lab-based IOPTH assay alone was used. Results: Of the 141 paired samples in group I, correlation between NBCL and the lab assay was high (rho=0.82; p<0.001). PTH levels using the NBCL assay dropped satisfactorily (>50% of the basal or 0 min sample; whichever was lower - i.e. positive test) in 23 patients; giving a positive predictive value of 100%. Of the 9 patients that did not demonstrate a drop, two were true negative (negative predictive value of 22%) leading to cure after excision of another gland. Group 1 (150 mins) had a significantly shorter 'in-theatre' time compared to group 2 (167 mins) (p=0.007); despite much higher use of near infra-red autofluorescence (NIRAF) (72% vs 11.6% in group I and 2 respectively). Conclusion: The NBCL CONNECT POC IOPTH assay gives comparable results to lab based PTH assays and can be performed without need for a centrifuge or qualified technicians. Surgeons, however, need to be aware of the potential for false-negative results.

Abnormal Calcium Levels are Associated With Worse Maternal and Fetal Outcomes; Results From an Exploratory Study.

CONTEXT: Precise estimates of the incidence of hyper- and hypocalcemia in pregnancy are unknown. Abnormal calcium levels have been associated with unfavorable pregnancy-related outcomes. OBJECTIVE: Determine frequency of hypercalcemia and hypocalcemia in pregnancy when tested and their associations with maternal and fetal outcomes. DESIGN: Exploratory retrospective cohort study. SETTING: Single tertiary care maternity unit. PATIENTS: Pregnant women with expected delivery date between 2017 and 2019 and a second additional cohort of pregnant women with hypercalcemia between 2014 and 2016 and 2020 and 2021. INTERVENTIONS: Observational. MAIN OUTCOMES MEASURED: (1) Incidence of hyper- and hypocalcemia when calcium tested; (2) maternal outcomes: incidence of preterm delivery, emergency cesarean section, and blood loss during delivery; and (3) fetal outcomes: fetal loss (miscarriage/stillbirth), neonatal intensive care unit admission, and fetal birth weight (for term deliveries). RESULTS: Total number of gestations and livebirths recorded were 33 118 and 20 969, respectively, with median [interquartile range] age of 30.1 [25.6-34.3] years. A total of 15.7% (n = 5197) of all gestations had albumin-adjusted calcium tested, and incidence of hypercalcemia and hypocalcemia when tested was 0.8% (n = 42) and 9.5% (n = 495), respectively. Both hypercalcemia (including additional cohort n = 89) and hypocalcemia were associated with increased incidence of preterm delivery (P < .001), emergency cesarean section (P < .001 and .019), blood loss (P < .001), and neonatal intensive care unit admission (P < .001). A total of 27% in the hypercalcemic group had an established diagnosis of primary hyperparathyroidism. CONCLUSIONS: Abnormal calcium levels during pregnancy are common and associated with worse pregnancy-related outcomes, which raises the possible need for routine calcium testing. Prospective studies to confirm the incidence, etiology, and effects of abnormal calcium in pregnancy are recommended.

Primary hyperparathyroidism in pregnancy: experience of a tertiary centre.

BACKGROUND AND PURPOSE: The management of primary hyperparathyroidism (PHPT) during pregnancy is challenging and there is no clear consensus on whether it increases the risk of complications in pregnancy. We conducted this study to review the maternal and fetal outcomes of pregnant women treated for PHPT in a single centre. METHODS: Data on relevant clinical parameters, demographics, management strategies, maternal and fetal outcomes were collected from the medical records of pregnant patients with PHPT diagnosed between 2012 and 2019. RESULTS: Of 15 pregnant women with PHPT, 6 were managed medically and 9 underwent surgery. The median age at their index pregnancy was 28 years [range 19-42]. The median highest adjusted calcium level in the medical group was 2.90 [range 2.61-3.25] mmol/L vs. 3.11 [2.78-4.95] mmol/L in the surgical group. There was one miscarriage and the stillbirth of twins in the medical group, but no such outcomes in the surgical group. The median gestational ages were 39 + 3 weeks [range 24 + 2-41 + 2 weeks] and 39 + 4 weeks [range 37 + 1-39 + 5 weeks] in the medical and surgical groups, respectively. No birth was complicated by neonatal tetany or convulsions. CONCLUSION: More complications developed in the pregnant PHPT patients who were managed medically than in those who underwent surgery. Surgery performed during the second trimester resulted in good outcomes. Multi-centre prospective studies are required to ascertain the risk of various complications in women with PHPT during pregnancy.

Quality of Life in Post-Surgical Hypoparathyroidism (PoSH) in Thyroid and Parathyroid Surgery.

BACKGROUND: Post-surgical hypoparathyroidism (PoSH) is often long term, with significant associated morbidity and ongoing treatment. A recent systematic review found impaired quality of life (QoL) in patients with PoSH, despite stable treatment. Most studies did not include an appropriate control arm and further studies were recommended, taking into account underlying disease and comorbidities. This study aims to compare QoL in patients with PoSH with appropriate control groups. METHODS: This was a cross-sectional observational study using the general quality of life SF-36 tool and a hypocalcaemia symptom score (HcSS) to assess QoL in patients with PoSH and controls (who had similar surgery but without PoSH). Participants were identified from two patient groups (the Butterfly Thyroid Cancer Trust and the Association for Multiple Endocrine Neoplasia Disorders) and a single tertiary centre in the UK. RESULTS: Four hundred and thirty-nine responses (female n = 379, PoSH n = 89) were included with a median (range) age of 52 (19-92) years. Reported dates of surgery ranged from 1973 to 2019. HcSS scores showed significantly more associated symptoms in patients with PoSH than those without (p < 0.001). Although there was no overall difference in QoL between groups, patients with PoSH consistently had lower scores (p = 0.008) in the energy/fatigue subdomain of the SF-36. CONCLUSION: Patients with PoSH reported significantly more fatigue and loss of energy compared to appropriately matched controls, but overall QoL was not significantly different. Standardised QoL measures may not be sensitive enough to highlight the impact on QoL in these patients. A disease-specific tool may be required.

Parathyroid hormone of ≥1.6 pmol/L at 6 months is associated with recovery in 'long-term' post-surgical hypoparathyroidism.

Objective: Post-surgical hypoparathyroidism (PoSH) usually settles within few months after thyroid surgery, but several patients require long-term supplementation with calcium/activated vitamin D. When PoSH persists beyond 6 months, it is considered 'chronic' or 'permanent', however, late recovery has been reported. The aim of this study was to determine the frequency of late recovery and explore factors predicting late recovery of parathyroid function. Methods: Adult patients undergoing total/completion thyroidectomy between 2009 and 2018 were included in this retrospective cohort observational study. The records of patients with evidence of PoSH were reviewed to identify those with persisting PoSH at 6 months. Demographic, biochemical, surgical, pathological, and clinical follow-up data were collected and analysed. Results: Out of 911 patients undergoing thyroidectomy, 270 were identified with PoSH. Of these, 192 were started on supplements and 138 (71.9%) recovered within 6 months. Of the remaining 54 patients, 35 had ongoing PoSH with median (range) follow-up of 3.4 (0.5-11.1) years. Nineteen patients were weaned off supplements and achieved remission at median (range) follow-up of 1.3 (0.6-4.8) years. All of those who recovered had a PTH of ≥1.6 pmol/L at 6 months. There was no difference in age, gender, diagnosis, type, and extent of surgery between those who did and did not show late recovery. Conclusions: Recovery from PoSH is common beyond 6 months, raising the question whether a 6-month threshold to define 'long-term' PoSH is appropriate. The chances of recovery are high (~50%) in patients with PTH level ≥1.6 pmol/L at 6 months, where attempts at weaning may be focussed.