The increasing burden of the 2-week wait colorectal cancer pathway in a single centre: the impact of faecal immunochemical tests

INTRODUCTION

Two-week wait (TWW) volume and colorectal cancer (CRC) detection pose an increasing challenge for NHS cancer services. Primary aims were to assess the introduction of faecal immunochemical tests (FIT) into clinical practice at our centre, the impact on TWW referral volume and CRC diagnoses, and to provide an update to previously published work. A secondary aim was to correlate FIT value and investigation.

METHODS

TWW CRC data following incorporation of FIT into clinical practice were analysed (1 June 2019-31 July 2021). Parameters assessed were monthly referral volume, CRC detection, primary care FIT volume and secondary care investigations. Referrals and CRC detection rates were compared with previously published data (2009-2019). Data relating to primary care FIT were collated from Berkshire and Surrey Pathology Services.

RESULTS

TWW referrals increased 360% (2009-2020). CRC incidence decreased from 8.87% to 3.24%. Following incorporation into clinical practice, primary care FIT requests have increased to >450/month and accompanied 1,722/4,796 referrals. CRC incidence is static (3-4%). Patients with FIT <10µg Hb/g faeces undergo radiological imaging more commonly, whereas FIT-positive patients are more likely to undergo endoscopy, although the difference is not statistically significant.

CONCLUSIONS

No significant change in CRC diagnosis was observed, despite increasing TWW referrals. Increasing utilisation of FIT in both primary and secondary care has helped maintain CRC detection while avoiding diagnostic delay. This study supports growing evidence highlighting the value of FIT in triage, referral and TWW investigation. FIT appears increasingly important for allocating secondary care resources (endoscopy), while guiding primary care referral. Additional low-cost strategies to determine prioritisation or reassurance (e.g. repeat FIT) require further evaluation.

Non-pain-related complaints of paediatric patients after dental treatment under general anaesthesia

AIM

To investigate the prevalence, duration, and severity of non-pain-related complaints after dental treatment under general anaesthesia (DTGA) and to identify correlating factors from patient's characteristics and treatment.

METHODS

Parents/caregivers of children treated under general anaesthesia were asked to fill in a dichotomous questionnaire during hospitalisation and the postoperative week. Several complaints were evaluated in relation to factors associated with dental treatment and general anaesthesia.

CONCLUSION

Postoperative morbidity after DTGA is common. Patients and their parents should be informed about the possibility of experiencing mild to moderate complaints, and adverse events that may last up to 7 days.

New method of remnant closure during distal pancreatectomy

PURPOSE

Pancreatic fistula following distal pancreatectomies still remains a relevant problem. The present study describes our first series with a new method of pancreatic remnant closure.

METHODS

A free fascia-peritoneum graft - harvested from the internal rectus sheet - was fixed onto the pancreatic stump by one circular stitch. The method was applied in 18 cases.

RESULTS

The postoperative hospital stay was 8 days in average. No clinically relevant postoperative pancreatic fistula (CR-POPF) developed. The morbidity rate was 39%, mostly Clavien-Dindo Grade II types. There was no reoperation or mortality.

CONCLUSION

The first series showed advantageous results with our method. Certainly, further studies are needed for the evaluation of this new and promising technique.

Patient-reported outcome measures show FIT as an acceptable investigation to rule out colorectal cancer in the two-week wait cohort

INTRODUCTION

Use of faecal immunochemical testing (FIT) for symptomatic patients is increasing. FIT is recommended as a triage tool from primary care to the two-week wait (TWW) suspected cancer pathway, but there is still little known about patient attitudes.

AIM

The aim of this study was to explore patient opinions of FIT and how it might be applied in the TWW pathway.

METHODS

A telephone survey was conducted for patients from the TWW pathway who had undergone both conventional colonic investigation and FIT. Five questions explored expectations, attitudes towards results and experience of the investigations using a Likert scale 1-5. Differences in opinion were compared using median and mode scores and visualised using bar charts.

RESULTS

One hundred and nine TWW patients agreed to answer the five questions. All had taken a stool sample for FIT, 50 underwent colonoscopy, 51 had a CT colonography and 8 underwent flexible sigmoidoscopy. Most patients (85%) scored 5 (completely satisfied) with these conventional colonic investigation methods they underwent for ruling out colorectal cancer (median 5). However, 30% of patients scored 5 (completely satisfied) if using a negative FIT to not require additional colonic investigation. The median score to perform FIT was 5 (very easy) compared with a median of 4 (easy) to undergo the other colonic investigations.

CONCLUSIONS

Symptomatic patients can perform FIT with little difficulty, and often would have been happy to avoid conventional colonic investigations with a negative result. However, shared decision-making should be employed to identify those who would be dissatisfied with relying on FIT for further investigation decisions.

Pain-related complaints of paediatric patients after dental treatment under general anaesthesia

AIM

To identify factors related to postoperative pain and to recognise strategies to reduce this pain after dental treatment under general anaesthesia.

METHODS

Cross-sectional observational study. Children treated under general ansesthesia reported pain daily using the Wong Baker FACES® Pain Rating Scale. Their parents/caregivers filled in a related Yes/No questionnaire during hospitalisation and the first postoperative week. The duration and severity of pain were evaluated in relation to various factors.

CONCLUSION

A well-established protocol is indicated to reduce operation time. Patients and their parents should be informed about the possibility of constantly subsiding postoperative pain that may last for a week. As additional local anaesthesia during general anaesthesia (GA) does not provide postoperative pain reduction in deciduous tooth extraction cases, its administration could be omitted.

Gastric outlet obstruction secondary to a wandering spleen: systematic review and surgical management of a case

INTRODUCTION

A wandering spleen occurs when laxity or absence of the suspensory ligaments allows migration throughout the abdomen. Gastric outlet obstruction resulting from this abnormality is rare. We present a systematic literature search and a case that was managed successfully with surgical intervention at our centre.

METHODS

A systematic search of the PubMed, Embase™, Medline^® and Google Scholar™ databases was carried out employing the combined search terms "gastric outlet obstruction" AND "wandering spleen". Six results were included for final analysis.

RESULTS

All six search results described a single case each. Patients underwent surgical management (open or laparoscopic) after initial investigation utilising a range of modalities. There were no mortalities reported at 90 days. The single case we present was complicated by gastric perforation; the patient made a successful recovery following open splenopexy and stapled wedge resection of the stomach.

CONCLUSIONS

A wandering spleen is a rare diagnosis and there are only six reported cases of gastric outlet obstruction secondary to a wandering spleen in the literature. None report associated gastric perforation. There are a variety of presenting symptoms, intraoperative findings and operative techniques used to address the gastrosplenic abnormality. The case reported by our centre adds to this limited evidence base and demonstrates a successful outcome from definitive surgical management. We highlight the need to seek early gastro-oesophageal expertise if any gastric pathology is found together with anatomical abnormality of the spleen.

Increased arterial stiffness predict major adverse cardiovascular events in post-infarcted patients. Do parameters and methods matter?

Introduction

According to recent 2021 ESC prevention guidelines arterial stiffness (aortic pulse wave velocity – PWV, augmentation index - Aix) predicts future major adverse cardiovascular events (MACE). Both parameters have a prognostic relevance, however due to the various technical approaches the level of high stiffness values show significant differences and resulting an argue against widespread use.

Purpose

We evaluated the cut-off PWV and Aix values for MACE prediction using cardiac magnetic resonance imaging (CMR) and oscillometric methods for validating the prognostic value of high stiffness parameters in post-infarcted patients.

Methods

CMR phase contrast imaging (Siemens Avanto, 1,5 T CMR device) and an invasively validated oscillometric based Arteriograph (AG) method were compared in this 6 years follow-up study, including 49 patients suffered previous ST-elevation myocardial infarction (STEMI). Patients received follow-up for MACE comprising all-cause death, non-fatal MI, ischemic stroke, hospitalization for heart failure and coronary revascularization.

Results

49 patients (37 male, average age: 57±8 years) were investigated. An acceptable agreement and significant correlation (Spearman's rho: 0.332, p&lt;0,01) was found between AG and CMR derived PWV values. Bland Altman plot was created to test for methods' agreement. The bias showed that in general the mean difference between the two measures was 3.6 m/s (upper and lower limit of agreement: –0.2 and 7.5 m/s). The coefficient of variation was 43.9%. Totally 51 MACE events occurred during the 6 years follow-up period. Hospitalisation for coronary revascularisation (55%), all-cause death (15%), non-fatal MI (12%), heart failure (12%) exposed the majority of MACE events. Optimized PWV and Aix cut-off values for MACE prediction were calculated (PWVCMR: 6,47 m/s; PWVAG: 9,625 m/s; AixAG: 34,22%) by receiver operating characteristic analysis (Figure 1). Kaplan-Meier analysis in all parameters showed a significantly lower event-free survival in case of high PWV and Aix values (Figure 2). Multivariate Cox regression analysis revealed PWV and Aix as a predictor of MACE (PWVCMR hazard ratio (HR): 1.31 (CI: 1.1–1.7), PWVAG HR: 1.24 (CI: 1.0–1.5), AixAG HR: 1,043 (CI: 1,01–1,08), p&lt;0,05 respectively).

Conclusions

Arterial stiffness, particularly elevated PWV predicts MACE in postinfarcted patients. Our study showed both CMR and oscillometric techniques are feasible for MACE prediction, however, adjusted cut-off values of PWV are recommended for different methods to improve individual risk stratification. All these findings emphasize the clinical relevance for the future measurement of arterial stiffness might contribute to improved risk stratification after MI, which is crucial for the assessment of prognosis and guidance of secondary prevention treatment.

Funding Acknowledgement

Type of funding sources: None.

O013 The increasing burden of the two-week wait colorectal cancer pathway within a single centre

Introduction

Increasing demand has placed colorectal cancer (CRC) two-week wait (TWW) pathways under pressure. The primary aims of this paper are to review TWW referral numbers and CRC diagnoses within our centre over the past 3 years (before, during and in recovery from the COVID-19 pandemic) and compare outcomes to our previously published data (2009–18). This incorporates the introduction of FIT into our clinical practice.

Methods

TWW CRC referral data from 1st July 2018–31st July 2021 was analysed. Parameters assessed; monthly TWW referrals, CRC detection, % of TWW referrals seen <14 days and investigations utilised. Data from January 2009 to 31 June 2018 was combined. Unpaired t-test was used to compare group means.

Results

TWW referrals have increased 360% from 2009 to 2020. The proportion of TWW referrals with CRC has decreased from 8.87% to 3.24% over this period, whilst the incidence of CRC remained static (mean 58.7 per annum). From 2009–18, TWW referrals=8921, CRC diagnoses=533, mean monthly CRC detection rate=4.7, ratio of referrals to CRC=16.7:1. From 2018–21, TWW referrals= 6523, CRC diagnoses=232, mean monthly CRC detection rate=6.3, ratio of referrals to CRC=28.4:1. There was a statistically significant difference in mean monthly referrals (p-value<0.00001) between the two periods.

Conclusion

Despite ever-increasing TWW referral numbers, no significant change in CRC diagnoses has occurred. We find our service under ever-increasing strain. Additional strategies and guidance are required to help address this. Further studies evaluating FIT and repeat FIT in the symptomatic TWW cohort may have a role in generating such a consensus.

Take-home message

Two week wait colorectal cancer referrals have increased 360% in 12 years. Colorectal cancer detection rate remains static over this timeframe.

A systematic review of symptomatic hamartomas of the jejunum and ileum

INTRODUCTION

Gastrointestinal hamartomas are rarely encountered benign growths made of an abnormal mixture of tissues normally found in the body where the growth occurs. Most hamartomas are asymptomatic and diagnosed incidentally. Evidence regarding symptomatic hamartomas of the jejunum and ileum is limited and restricted to anecdotal case reports. We aim to provide a contemporary overview to clarify various aspects linked to symptomatic hamartomas, helping aide management and clinical decision-making.

METHODS

The search terms 'small bowel', 'small intestine', 'jejunum' and 'ileum' were combined with 'hamartoma'. Embase, Medline, PubMed searches and Google Scholar hand-searches were conducted. All English language papers from 1 January 2000 to 1 June 2020 were included.

RESULTS

In total 39 cases were reviewed: 29 adults and 10 paediatric (0-16 years). Presenting symptoms included abdominal pain (87%), vomiting (56%), gastrointestinal bleeding (20.5%) and weight loss (5%); 36 of 39 cases (92%) presented as emergencies. Diagnostic investigations included: abdominal x-ray (49%), endoscopy (38%), computed tomography (56%), magnetic resonance imaging (5%), contrast study (15%) and video capsule endoscopy (5%). Initial management strategy was either open (30) or laparoscopic (7) surgery or endoscopy (2). All cases required surgery for definitive management. Twenty-five cases recorded hamartoma size, and mean maximum diameter was 3.56cm (1.2-8cm) with stricturing in seven cases. Nine of the 39 cases were associated with hamartomatous syndromes. Two mortalities were recorded.

CONCLUSIONS

This is the first published review addressing symptomatic hamartomas of the jejunum and ileum. New data relating to demographic cohort, symptom profile, investigations, management strategies, and morbidity and mortality provide greater insight to those encountering this challenging clinical finding in the future.

Evaluation of pulse wave velocity for predicting major advanced cardiovascular events in patients with chronic myocardial infarction

Introduction

Increased aortic pulse wave velocity (PWV) as a strong predictor of major advanced cardiovascular events (MACE) has a prognostic relevance in patients after myocardial infarction (MI). Several non-invasive methods have been proposed for the assessment of arterial stiffness, but the PWV values show significant differences according to the applied techniques. Cardiac magnetic resonance imaging (CMR) provides an accurate method to measure PWV and infarct size in patients after MI.

Purpose

Calculated PWV values of CMR based phase-contrast (PC) and invasively validated oscillometric methods were compared in this prospective observational study. We aimed to evaluate the cut-off PWV values for each method, while MACE predicted and validated the prognostic value of high PWV in post-infarcted patients in a 6-year follow-up.

Methods

3D aortic angiography and PC velocity imaging was performed using a Siemens Avanto 1,5 T CMR device. Oscillometric based Arteriograph (AG) was used to assess PWV using direct body surface distance measurements. The comparison between the two techniques was tested. Patients received follow-up for MACE comprising all-cause death, non-fatal MI, ischemic stroke, hospitalization for heart failure and coronary revascularization. Event-free survival was analysed using Kaplan-Meier plots and log-rank tests. Univariable and multivariable Cox regression analysis was performed to identify outcome predictors.

Results

75 patients (56 male, 19 female, average age: 56±13 years) referred for CMR were investigated, of whom 50 had coronary artery disease (CAD) including 35 patients with previous MI developing ischaemic late gadolinium enhancement (LGE) pattern. AG and CMR derived PWV values were significantly correlated (rho: 0,343, p&lt;0,05), however absolute PWV values were significantly higher for AG (median (IQR): 10,4 (9,2–11,9) vs. 6,44 (5,64–7,5); p&lt;0,001). Bland Altman analysis showed an acceptable agreement with a mean difference of 3,7 m/s between the two measures. In patients with CAD significantly (p&lt;0,01) higher PWV values were measured by AG and CMR, respectively. During the median follow-up of 6 years, totally 69 MACE events occurred. Optimized PWV cut-off values for MACE prediction were calculated (CMR: 6,47 m/s; AG: 9,625 m/s) by receiver operating characteristic analysis. Kaplan-Meier analysis in both methods showed a significantly lower event-free survival in case of high PWV (p&lt;0,01, respectively). Cox regression analysis revealed PWV for both methods as a predictor of MACE (PWV CMR hazard ratio (HR): 2,6 (confidence interval (CI) 1,3–5,1), PWV AG HR: 3,1 (CI: 1,3–7,1), p&lt;0,005, respectively).

Conclusions

Our study showed good agreement between the AG and CMR methods for PWV calculation. Both techniques are feasible for MACE prediction in postinfarcted patients. However, different AG and CMR PWV cut-off values were calculated to improve risk stratification.

Funding Acknowledgement

Type of funding sources: None. Agreement between the two methodsKaplan-Meier event curves for MACE

343 A Systematic Review of Symptomatic Hamartomas of The Jejunum and Ileum

Introduction

Gastrointestinal hamartomas are rarely encountered benign growths made of an abnormal mixture of tissues normally found in the body where the growth occurs. Most hamartomas are asymptomatic and diagnosed incidentally. Evidence regarding symptomatic hamartomas of the jejunum and ileum is limited.

Method

The search terms ‘small bowel,’ ‘small intestine,’ ‘jejunum’ and ‘ileum’ were combined with ‘hamartoma.’ EMBASE, Medline, PubMed searches and Google Scholar hand searches were conducted. All English language papers from 01/01/2000-01/06/2020 were included.

Results

A total of 39 cases were reviewed, 29 adults and 10 paediatric (0-16 years). Presenting symptoms included: abdominal pain (87%), vomiting (56%), gastrointestinal bleeding (20.5%) and weight loss (5%). Stricturing was noted in 7 cases. 36/39 (92%) presented as emergencies. Diagnostic investigations included: Abdominal X-ray (49%), endoscopy (38%) and CT (56%). Initial management strategy was either open (30) or laparoscopic (7) surgery or endoscopy (2). All cases required surgery for definitive management. 9/39 cases were associated with hamartomatous syndromes. 2 mortalities were recorded.

Conclusions

This is the first review addressing symptomatic hamartomas of the jejunum and ileum. New data relating to demographic cohort, symptom profile, investigations, management strategies and morbidity and mortality provide greater insight to those encountering this challenging clinical finding in the future.

Application of a fast and cost-effective 'three-in-one' MMR ELISA as a tool for surveying anti-MMR humoral immunity: the Hungarian experience

In Hungary, between February 2017 and July 2019, 70 confirmed measles cases were reported, raising questions about the adequacy of population-level immunity. Although the assumed vaccination coverage is ≥99%, in a recent study, we detected potential gaps in the anti-measles humoral immunity. In Hungary, according to a decree by the Ministry of Public Welfare, beginning from 2021, the healthcare provider should conduct a serosurvey of anti-measles protection levels of healthcare professionals. To facilitate the compliance with this requirement, we developed a quick 'three-in-one' or 'triple' MMR (measles, mumps and rubella) indirect ELISA (IgG); an assay format that is currently not available commercially. High throughput applicability of the 'three-in-one' ELISA was verified using 1736 sera from routine laboratory residual samples, using an automated platform (Siemens BEP 2000 Advance). Assay verification was performed by comparing the full antigen repertoire-based 'target' assay with in-house 'control' assays using recombinant viral antigen coatings, and by validated commercially available kits. Indirect immunofluorescence was used as an independent reference method. Data were analysed using OriginLab, IBM SPSS, RStudio and MedCalc. In case of measles, we combined our current results with previously published data (Ntotal measles = 3523). Evaluation of anti-mumps and anti-rubella humoral antibody levels was based on the measurement of 1736 samples. The lowest anti-measles seropositivity (79.3%) was detected in sera of individuals vaccinated between 1978 and 1987. Considering the antigen-specific seropositivity ratios of all samples measured, anti-measles, -mumps and -rubella IgG antibody titres were adequate in 89.84%, 91.82% and 92.28%, respectively. Based on the virus-specific herd immunity threshold (HIT) values (HITMeasles = 92-95%, HITMumps = 75-86%, HITRubella = 83-86), it can be stated that regarding anti-measles immunity, certain age clusters of the population may have inadequate levels of humoral immunity. Despite the potential gaps in herd immunity, the use of MMR vaccine remains an effective and low-cost approach for the prevention of measles, mumps and rubella infections.

Correlation of natural autoantibodies and cardiovascular disease-related anti-bacterial antibodies in pericardial fluid of cardiac surgery patients

Our previous studies showed that anti-citrate synthase (anti-CS) immunoglobulin (Ig)M natural autoantibodies are present in healthy individuals without previous antigen stimulation, but no studies have investigated their presence in the pericardial fluid (PF). Therefore, we detected the natural anti-CS IgG/M autoantibody levels in plasma and PF of cardiac surgery patients and investigated their relationship with cardiovascular disease-associated bacterial pathogens. PF and blood samples of 22 coronary artery bypass graft (CABG) and 10 aortic valve replacement (AVR) patients were tested for total Ig levels, natural autoantibodies and infection-related antibodies using enzyme-linked immunosorbent assay (ELISA) and Luminex methods. The B cell subsets were measured by flow cytometry. The total Ig subclass levels were four to eight times lower in PF than in plasma, but the natural anti-CS IgM autoantibodies showed a relative increase in PF. The frequency of CD19⁺ B lymphocytes was significantly lower in PF than in blood (P = 0·01), with a significant relative increase of B1 cells (P = 0·005). Mycoplasma pneumoniae antibody-positive patients had significantly higher anti-CS IgM levels. In CABG patients we found a correlation between anti-CS IgG levels and M. pneumoniae, Chlamydia pneumoniae and Borrelia burgdorferi antibody titres. Our results provide the first evidence that natural autoantibodies are present in the PF, and they show a significant correlation with certain anti-bacterial antibody titres in a disease-specific manner.

A three-year follow-up study of the development of joint contractures in 131 patients with systemic sclerosis

OBJECTIVES

To analyse the correlation between the number of joint-contractures and other major clinical findings in a follow-up study of 131 patients with systemic sclerosis (SSc).

METHODS

The range of motion of joints (ROM), HAQ-DI, and the major clinical characteristics were assessed.

RESULTS

A high frequency of contractures (ROM<75% of the normal) were present at baseline in small joints of the hand (82%), wrists (75%), and shoulders (50%). ROM of the dominant side hand was significantly more decreased compared to the non-dominant side. The number of the upper extremity contractures correlated positively with ESR (p<0.01), CRP (p<0.01), HAQ-DI (p<0.01), and negatively with forced vital capacity (FVC) (p<0.05). The number of contractures was not significantly different in cases with early (≤ 4 years) and late disease duration in both the limited and diffuse subgroups. During the three-year follow-up period, an increase in the number of joint contractures (ROM<75%) was associated with an increase of ESR, modified Rodnan's skin score, and the European Scleroderma Study Group Activity Index by multiple linear regression analysis. Univariate analysis over a six-year period demonstrated poor outcome in patients with more than ten contractures, or more than four contractures of unilateral hand-joints.

CONCLUSIONS

Contractures predominantly develop during the early years following disease onset in both SSc subgroups. Inflammation and skin-involvement are significant contributing factors for the development of contractures. The dominant hand may be more pronouncedly impaired compared to the non-dominant side. A high number of joint-contractures might be an unfavourable prognostic factor in SSc.

High-voltage nanoimprint lithography of refractory metal films

Local oxidation of metal, semiconductor, and polymer surfaces has provided a common basis from which to explore fundamental principles of nanolithography and prototype functional nanostructures for many years now. This article summarizes an investigation of local oxidation for iron and Group IV metal thin films using both scanning probe microscopy and high-voltage nanoimprinting methods. We illustrate how the underlying kinetics of metal oxidation in the presence of nitrogen, which is incorporated into the metal film during the growth process, is dramatically enhanced compared with that of single-crystal silicon. We then go on to demonstrate subsequent selective etching of latent features and a potential magnetic application.

Physical characterization methods for iron oxide contrast agents encapsulated within a targeted liposome-based delivery system

Intact liposome-based targeted nanoparticle delivery systems (NDS) are immobilized by non-selective binding and characterized by scanning probe microscopy (SPM) in a fluid imaging environment. The size, size distribution, functionality, and stability of an NDS with a payload consisting of a super-paramagnetic iron oxide contrast agent for magnetic resonance imaging are determined. SPM results are combined with information obtained by more familiar techniques such as superconducting quantum interference device (SQUID) magnetometry, dynamic light scattering, and electron microscopy. By integrating the methods presented in this work into the NDS formulation and manufacturing process, size-dependent statistical properties of the complex can be obtained and the structure-function relationship of individual, multi-component nanoscale entities can be assessed in a reliable and reproducible manner.

High-voltage SPM oxidation of ZrN: materials for multiscale applications

Scanning probe microscope (SPM) oxidation was used to form zirconium oxide features on 200 nm thick ZrN films. The features exhibit rapid yet controlled growth kinetics, even in contact mode with 70 V dc applied between the probe tip and substrate. The features grown for times longer than 10 s are higher than 200 nm, and reach more than 1000 nm in height after 300 s. Long-time oxidation experiments and selective etching of the oxides and nitrides lead us to propose that as the oxidation reaches the silicon substrate, delamination occurs with the simultaneous formation of a thin layer of new material at the ZrN/Si interface. High-voltage oxide growth on ZrN is fast and sustainable, and the robust oxide features are promising candidates for multiscale (nanometre-to-micrometre) applications.

Body surface potential field representation fidelity: analysis of map estimation procedures

The first part of this study analyzed the spatial-temporal error distribution of the Lux-type limited lead system. Quantitative new evidence is reported that the 32-lead anterior subset estimates the further 160 leads with an average amplitude error less than 38.5 microV. The spatial error distribution revealed 8 sites where the error is the highest, primarily on the anterior side, independent of the clinical classification. The second part of the study examined inter-lead-system conversion strategies for interpolating the Lux-192 lead maps from the Montreal-63 data. The methodology based on the Laplacian interpolation yielded an average amplitude error of 143.7 microV and an average correlation of 0.87 for pattern fidelity. In this specific case a modified linear interpolation surpassed the Laplacian method. A presented example illustrates that even in cases when the fidelity of the signal information is heavily compromised the diagnostic information may remain less influenced.