Incidence of primary large vessel vasculitis in Norfolk, UK from 2011 to 2020

OBJECTIVES

To report the annual incidence of primary large vessel vasculitis (LVV) in the adult population of Norfolk County, UK, including giant cell arteritis (GCA) (in those ≥50 years) and Takayasu arteritis (TAK).

METHODS

Individuals diagnosed by histology or imaging who lived in NR1-NR30 postcode districts were included. Validated criteria from 1990 and 2022 were applied for final classification. Population data were available from the Office of National Statistics, UK.

RESULTS

270 individuals were diagnosed with primary LVV over 4.7 million person-years. The annual incidence (95% CI) of primary LVV was 57.5 (50.8, 64.7)/million person-years in the adult population. 227 and 244 individuals were diagnosed with GCA over ~2.5 million person-years using 1990 and 2022 criteria, respectively. The annual incidence (95% CI) of GCA was 91.6 (80.0, 104.3)/million person-years aged ≥50 years using 1990 criteria and 98.4 (86.4, 111.6)/million person-years aged ≥50 years using 2022 criteria. 13 and 2 individuals were diagnosed with TAK over 4.7 million person-years. The annual incidence (95% CI) of TAK was 2.8 (1.5, 4.7)/million person-years using 1990 criteria and 0.4 (0.0, 1.4)/million person-years using 2022 criteria, in the adult population. The incidence of GCA rose sharply in 2017 coincident with the introduction of a fast-track pathway and fell during the pandemic when the pathway was disrupted.

CONCLUSIONS

This is the first study that reports the incidence of objectively verified primary LVV in the adult population. The incidence of GCA may be affected by the availability of diagnostic pathways. The use of the 2022 classification criteria results in a rise in the classification of GCA and fall in that of TAK.

Effectiveness of SPECT/CT Imaging for Sentinel Node Biopsy Staging of Primary Cutaneous Melanoma and Patient Outcomes

Purpose

Coregistered SPECT/CT can improve accuracy of sentinel node biopsy (SNB) for staging melanoma. This benefit has implications for pathology services and surgical practice with increased diagnostic and surgical workload. The purpose of this study was to investigate the effectiveness of SPECT/CT imaging.

Methods

SNB data were collected over a 10-year period. Preoperative SLN mapping was performed by using planar lymphoscintigraphy (LSG) for all patients (n = 1522) and after October 2015, patients underwent a second co-registered SPECT/CT scan (n = 559). The patients were stratified according to the imaging protocol. The number of nodes and nodal basins were assessed. The reasons for cancellation also were assessed.

Results

A total of 95% (1446/1522) of patients underwent a successful SNB procedure. Significantly more sentinel nodes were identified by the SPECT/CT protocol (3 vs. 2; p < 0.0001). More patients were cancelled in the SPECT/CT cohort (9.3% vs. 2.5%; p < 0.0001). Head & neck, lower limb, and AJCC IB primaries were significantly less likely to proceed to SNB. SPECT/CT identified significantly more positive SNBs (20.9% vs. 16.5%; p = 0.038). SPECT/CT imaging was associated with improved disease-free (hazard ratio [HR] = 0.74; 95% confidence interval [CI]: 0.54–1.0); p = 0.048) and disease-specific survival (HR = 0.48; 95% CI: 0.3–0.78; p = 0.003). Patients who did not proceed to SNB had a significantly increased nodal relapse rate (23.5% vs. 6.8%; HR = 3.4; 95% CI: 1.9–6.2; p < 0.0001) compared with those who underwent SNB.

Conclusions

This large cohort study confirms the increased accuracy of SPECT/CT for identifying SLN metastases, which would appear to have a significant therapeutic benefit, although an increased risk of cancellation of the SNB procedure on the day of surgery.

Erdheim-Chester Disease: Two cases from an ophthalmic perspective

Purpose

We report two patients who presented initially to ophthalmology clinics with symptoms and signs of orbital inflammation that led to a diagnosis of Erdheim-Chester Disease (ECD).

Observations

ECD is a rare form of non-Langerhans cell histiocytosis (LCH) which is characterised by multi-system organ involvement and poor prognosis with standard therapies. Both patients were positive for the BRAF V600E mutation on genetic testing and were treated with the BRAF inhibitors Vemurafenib and Dabrafenib respectively. These cases highlight the variable clinical presentation and course of ECD, the classical radiological and histopathological findings, and the high degree of clinical suspicion necessary to reach this diagnosis.

Conclusions and importance

The combination of xanthelasma and bilateral, diffuse intraconal orbital masses must suggest to the clinician the possibility of ECD; and consideration to arrange further investigation with a full body CT or FDG PET/CT scan should be given, even in the absence of wider systemic symptoms or signs. With the advent of targeted therapies such as BRAF inhibitors, it is of even more importance that a diagnosis of ECD is established in a timely manner in order to give these patients the best chance of reduced morbidity and increased survival.

MicroRNA expression in a phosphaturic mesenchymal tumour

Phosphaturic mesenchymal tumours are a heterogeneous set of bone and soft tissue neoplasms that can cause a number of paraneoplastic syndromes such as tumour induced osteomalacia. The term phosphaturic comes from the common finding that these tumours secrete high levels of fibroblast growth factor 23 which causes renal phosphate wasting leading to hypophosphatemia. Phosphaturic mesenchymal tumours are rare and diagnosis is difficult. A very active 68 year old male presented with bone pain and muscle weakness. He was hypophosphataemic and total alkaline phosphatase was markedly elevated. The patient was placed on vitamin D supplementation but his condition progressed. In the fifth year of presentation the patient required the use of a wheelchair and described “explosive” bone pain on physical contact. Serum 1,25 dihydroxyvitamin D was low and serum fibroblast growth factor 23 was significantly elevated, raising suspicion of a phosphaturic mesenchymal tumour. A lesion was detected in his left femoral head and the patient underwent a total hip replacement. The patient displayed a rapid improvement to his condition and during a three year follow up period he returned to an active lifestyle. As molecular testing may help provide a robust diagnosis and is particularly useful in rare diseases we took a next generation sequencing approach to identify a differential expression of small RNAs in the resected tumour. Small RNAs are non-coding RNA molecules that play a key role in regulation of gene expression and can be used as specific biomarkers. We found an upregulation of miR-197. We also found a downregulation of miR-20b, miR-144 and miR-335 which is a small RNA profile typical of osteosarcoma. MiR-21, the most frequently upregulated microRNA in cancer, was downregulated. We conclude that the specific small RNA profile is typical of osteosarcoma except for the downregulation of oncogenic miR-21. Transcriptional plasticity of miR-197, which is computationally predicted to target fibroblast growth factor 23 messenger RNA, may be upregulated in a cellular effort to correct the ectopic expression of the protein.

Technetium-99m Methylene Diphosphonate Single-photon Emission Computed Tomography/Computed Tomography of the Foot and Ankle

The complex anatomy and function of the foot and ankle can make it difficult to determine the cause of symptoms in patients with foot and ankle pathology. Following initial clinical and radiographic assessment, additional imaging with magnetic resonance imaging may be required, which is often seen as the modality of choice. Although sensitive to pathological changes in bone metabolism and vascularity, technetium-99m (Tc-99m) bone scintigraphy often lacks the specificity and resolution required to evaluate the structures of the foot and ankle. Tc-99m methylene diphosphonate single-photon emission computed tomography/computed tomography (SPECT/CT) combines this sensitivity with the superior anatomical detail of CT, enabling better localization of pathological uptake and evaluation of associated structural changes. As a result, SPECT/CT has been growing in popularity for the assessment of patients with foot and ankle pathology where it can provide additional information that may change the initial diagnosis and subsequent management plan. Studies have reported modification of the surgical approach and site of intra-articular local anesthetic injections following SPECT/CT with good results. Interpretation of SPECT/CT studies requires an understanding of the pathological changes that result in increased tracer accumulation in addition to the CT changes that may be seen. This review aims to highlight the advantages of SPECT/CT, potential applications and explain the imaging appearances of common pathologies that may be observed.

Positron Emission Tomography Computed Tomography: A Guide for the General Radiologist

Cancer remains a leading cause of death in Canada and worldwide. Whilst advances in anatomical imaging to detect and monitor malignant disease have continued over the last few decades, limitations remain. Functional imaging, such as positron emission tomography (PET), has improved the sensitivity and specificity in detecting malignant disease. In combination with computed tomography (CT), PET is now commonly used in the oncology setting and is an integral part of many cancer patients' pathways. Although initially the CT component of the study was purely for attenuation of the PET imaging and to provide anatomical coregistration, many centers now combine the PET study with a diagnostic quality contrast enhanced CT to provide one stop staging, thus refining the patient's pathway. The commonest tracer used in everyday practice is FDG (F18-fluorodeoxyglucose). There are many more tracers in routine clinical practice and those with emerging roles, such as 11C-choline, useful in the imaging of prostate cancer; 11C-methionine, useful in imaging brain tumours; C11-acetate, used in imaging hepatocellular carcinomas; 18F-FLT, which can be used as a marker of cellular proliferation in various malignancies; and F18-DOPA and various 68Ga-somatostatin analogues, used in patients with neuroendocrine tumours. In this article we concentrate on FDG PETCT as this is the most commonly available and widely utilised tracer now used to routinely stage a number of cancers. PETCT alters the stage in approximately one-third of patients compared to anatomical imaging alone. Increasingly, PETCT is being used to assess early metabolic response to treatment. Metabolic response can be seen much earlier than a change in the size/volume of the disease which is measured by standard CT imaging. This can aid treatment decisions in both in terms of modifying therapy and in addition to providing important prognostic information. Furthermore, it is helpful in patients with distorted anatomy from surgery or radiotherapy when there is suspicion of recurrent or residual disease. FDG PETCT is not specific for malignancy and can also be used for diagnosing and monitoring a number of inflammatory and infectious conditions that can be difficult to diagnose on anatomical imaging, some of which carry significant morbidity. FDG PETCT is increasingly used in patients with pyrexia of unknown origin and in patients with metastatic malignancies of unidentified primary on conventional imaging. This article reviews the uses of PETCT including an overview of the more common incidental lesions and conditions. It also provides guidance of how to approach a PETCT as a nonradionuclide radiologist and how to interpret a study in the multidisciplinary team setting.

Does 99mTc-MDP bone scintigraphy add to the investigation of patients with symptomatic unicompartmental knee replacement?

AIM

The purpose of this study was to determine whether nuclear medicine (99m)Tc-Methyl diphosphonate bone scintigraphy ((99m)Tc-MDP bone scintigraphy) added information over plain radiographs loosening infection in symptomatic unicompartmental knee replacements (UKRs).

METHODS AND MATERIALS

A cohort of 39 patients who presented with knee pain following UKR was retrospectively reviewed. All had undergone nuclear medicine bone scans for possible loosening or infection of the prosthesis. The findings of the bone scintigraphy were compared to subsequent operative findings during diagnostic arthroscopic investigation or revision surgery for those patients who had undergone these procedures.

RESULTS

Of the 39 patients with painful knees following UKR, surgical findings confirmed that 11 had either loose (n=9) or infected (n=2) implants. Logistic regression analysis demonstrated no statistically significant combination of features on nuclear medicine or radiographs associated with failure of the prosthesis due to infection or loosening (p>0.05). Classification of a satisfactory position of the UKR on plain radiography exhibited a high negative predictive value (96% for infections, and 80% for loosening). However, plain radiograph was not sensitive for loosening (50%) or infection (37%) of the UKR with very low positive predictive values (9.1% for infection and 27.3% for loosening).

CONCLUSION

This study provides no evidence to support the routine use of (99m)Tc-MDP bone scintigraphy in the clinical decision-making for patients with a painful UKR.

LEVEL OF EVIDENCE

level 4.

Neck dissection can be avoided after sequential chemoradiotherapy and negative post-treatment positron emission tomography-computed tomography in N2 head and neck squamous cell carcinoma

AIMS

This study assessed neck control in patients with N2 head and neck squamous cell carcinoma (HNSCC) treated with sequential chemoradiotherapy (SCRT) and the incidence of neck recurrence when neck dissection was withheld in those with negative post-treatment fluorine-18 fluorodeoxyglucose positron emission tomography (FDG PET).

MATERIALS AND METHODS

Thirty-four consecutive patients with N2 HNSCC who were treated with radical intent using SCRT were included. Twenty-seven patients received concomitant platinum-based chemotherapy with their radiotherapy. Nineteen patients were treated with intensity-modulated radiotherapy. PET-computed tomography (PET-CT) was obtained 3 months after the completion of radical radiotherapy. Neck dissection was carried out only in those with increased FDG uptake in the neck.

RESULTS

The median follow-up was 39.1 months. One patient had increased FDG uptake in the neck post-treatment, which was false positive for malignancy. The remaining 33 patients were observed without neck dissection. No regional recurrence occurred. The negative predictive value (NPV) of post-treatment PET-CT was 100%.

CONCLUSIONS

Good disease control in the neck can be achieved in patients with N2 HNSCC with SCRT. Post-treatment PET-CT has a high NPV. Neck dissection can be avoided if post-treatment PET-CT is negative.

Unexpected changes in clinical diagnosis: early abdomino-pelvic computed tomography compared with clinical evaluation

BACKGROUND

To evaluate the value of early computed tomography (CT) on identifying clinically "unexpected" diagnosis in patients presenting with "non specific" acute abdominal pain.

MATERIALS AND METHODS

All patients presenting to on-call surgeons with acute abdominal pain were eligible study participants. Patients were randomised to CT within one hour of admission or supine abdominal and erect chest radiography. Ninety-nine patients randomized to CT arm were reviewed for the purpose of this study. The number and severity of unexpected and/or incidental diagnoses detected on the CT were assessed.

RESULTS

In 20 of the 99 patients CT revealed primary or secondary diagnoses, which were unexpected following the initial clinical examination and led to completely different therapeutic options. In 15 of those 20 patients CT revealed clinically unexpected conditions, whereas in two patients severe complications of the clinically suspected diagnosis were detected on CT. Five patients had significant incidental findings in addition to their primary diagnosis on CT. In two of these patient CT also revealed clinically unexpected diagnoses.

CONCLUSION

Early CT has the advantage of detecting unexpected clinically significant primary and secondary diagnoses in patients presenting with acute abdominal pain and best guides the surgeon to the appropriate patient management.

A randomized, controlled trial of routine early abdominal computed tomography in patients presenting with non-specific acute abdominal pain

AIM

To compare the effect of an initial early computed tomography (CT) examination versus standard practice (SP) on the length of hospital stay, diagnostic accuracy, and mortality of adults presenting with acute abdominal pain.

MATERIALS AND METHODS

Two hundred and five adults presenting with acute abdominal pain were randomized to undergo an early CT examination or current SP, which comprised supine abdominal and erect chest radiography. One hundred and ninety-eight patients (99 in each arm) were included in the analysis. The primary endpoint was the duration of inpatient stay; secondary endpoints were diagnostic certainty and mortality.

RESULTS

There was no significant difference in the length of hospital stay between the two arms (p=0.20). At randomization 36% (35 of 96) of CT patients and 49% (48 of 98) of SP patients were correctly diagnosed; 24h after randomization the correct diagnosis had been established in 84% of CT patients and 73% of SP patients. This refinement in diagnostic certainty was significantly better in the CT group (p<0.001). There was no difference in mortality between the two trial arms (p=0.31).

CONCLUSION

Early abdominal CT in patients with acute abdominal pain improves diagnostic certainty, but does not reduce the length of hospital stay and 6 month mortality.

Healthy passive cigarette smokers have increased pulmonary alveolar permeability

QUESTION

Does passive smoking have a measurable effect on lung function in otherwise healthy subjects? There is current interest concerning passive smoking but no objective evidence showing that it has any impact on lung function.

METHODS

The pulmonary clearance rate of (99m)Tc-DTPA was measured in 21 healthy volunteers after inhalation as a radio-aerosol and compared between healthy cigarette smokers, passive smokers and non-smokers. All volunteers had normal lung function.

RESULTS

Clearance half-times in healthy passive smokers (n=5) were longer than in healthy smokers (n=6) but clearly shorter compared with healthy non-smokers (n=10) with respective mean values of 45.2 (SD 8.3), 24.3 (8.6) and 80.3 (20) min.

CONCLUSION

Passive smoking has a functional impact on the lung blood/gas barrier.

A simple processing method allowing comparison of renal enhancing volumes derived from standard portal venous phase contrast-enhanced multidetector CT images to derive a CT estimate of differential renal function with equivalent results to nuclear medicine quantification

As iodinated contrast medium is cleared by glomerular filtration, it should be possible to apply the same principles utilized in radionuclide studies to derive differential renal function by comparison of enhancing renal volumes derived from contrast enhanced multidetector CT (CEMDCT). Having established a technique iteratively which appeared successful, a retrospective study was performed using 25 consecutive patients with a wide range of urological conditions who had undergone both CEMDCT, including the renal area in the portal venous phase, and nuclear medicine (NM) assessment of renal function with no urological intervention between the studies. Proprietary volume software was used to quantify the volume and attenuation of each kidney, the products of which (after subtraction of soft tissue attenuation derived from a region of interest over psoas) gave right and left enhancing renal volumes. The contribution by each kidney as a percentage of total renal enhancing tissue was derived. Comparison with NM studies resulted in excellent correlation of relative renal function by CEMDCT and NM assessments having a regression of near unity and a Pearson's correlation coefficient of 0.96. Bland Altman and Passing Bablock tests confirmed good agreement between the two methods with no bias. This is a simple, practicable processing technique using standard portal venous phase CEMDCT images to quantify differential function. This technique may allow a one-stop CT assessment of both anatomy and function.