A Pictorial Review of I-123 MIBG Imaging of Neuroblastoma Utilizing a State-of-the-Art CZT SPECT/CT System

The field of nuclear medicine is entering a new era of gamma-camera technology. Solid-state SPECT/CT systems will gradually replace the thallium-activated sodium-iodide NaI(Tl) systems. This digital technology allows drastic improvements in image quality, radiotracer dose reduction, and procedure efficiency. This pictorial review presents our initial experience on an NM/CT 870 CZT system (GE Healthcare), equipped with dual-head cadmium zinc telluride (CZT) detectors, for I-123 metaiodobenzylguanidine (MIBG) imaging in pediatric neuroblastoma. On planar imaging, CZT shows greater image quality than at conventional gamma-camera using the Infinia Hawkeye (GE Healthcare). Physiologic structures such as salivary glands and myocardium show sharper borders with a more notable signal-to-noise ratio at CZT than conventional gamma camera. On SPECT imaging, the CZT scanner, combined with resolution recovery, demonstrates either comparable or greater image quality at 80% of the conventional gamma camera’s acquisition time. Due to the 2.46-mm detector pixel with fully registered collimator holes matching each pixel and direct conversion of photons into electrical signals, the CZT gamma camera system provides significant advantages in photon localization and energy resolution.

Nasal epithelial cell culture fluorescence recovery after photobleaching predicts cystic fibrosis therapeutic response

Background

Human nasal epithelial (HNE) cells can be sampled noninvasively and cultured to provide a model of the airway epithelium that reflects cystic fibrosis (CF) pathophysiology. We hypothesised that in vitro measures of HNE cell physiology would correlate directly with in vivo measures of lung physiology and therapeutic response, providing a framework for using HNE cells for therapeutic development and precision medicine.

Methods

We sampled nasal cells from participants with CF (CF group, n=26), healthy controls (HC group, n=14) and single CF transmembrane conductance regulator (CFTR) mutation carrier parents of the CF group (CR group, n=16). Participants underwent lung physiology and sweat chloride testing, and nuclear imaging-based measurement of mucociliary clearance (MCC) and small-molecule absorption (ABS). CF participants completed a second imaging day that included hypertonic saline (HS) inhalation to assess therapeutic response in terms of MCC. HNE measurements included Ussing chamber electrophysiology, small-molecule and liquid absorption rates, and particle diffusion rates through the HNE airway surface liquid (ASL) measured using fluorescence recovery after photobleaching (FRAP).

Results

Long FRAP diffusion times were associated with increased MCC response to HS in CF. This implies a strong relationship between inherent factors affecting ASL mucin concentration and therapeutic response to a hydrating therapy. MCC decreased with age in the CR group, which had a larger range of ages than the other two groups. Likely this indicates a general age-related effect that may be accentuated in this group. Measures of lung ABS correlated with sweat chloride in both the HC and CF groups, indicating that CFTR function drives this measure of paracellular small-molecule probe absorption.

Conclusions

Our results demonstrate the utility of HNE cultures for assessing therapeutic response for hydrating therapies. In vitro measurements of FRAP were particularly useful for predicting response and for characterising important properties of ASL mucus that were ultimately reflected in lung physiology.

Coronary angiographic findings for out-of-hospital cardiac arrest survivors presenting with nonshockable rhythms and no ST elevation post resuscitation

BACKGROUND

Recent guidelines suggest that coronary angiography (CAG) should be considered for out-of-hospital cardiac arrest (OHCA) survivors, including those without ST elevation (STE) and without shockable rhythms. However, there is no prospective data to support CAG for survivors with nonshockable rhythms and no STE post resuscitation.

METHODS

This was a re-analysis of the PEARL study (randomized OHCA survivors without STE to early CAG versus not). Patients were subdivided by initial rhythm as nonshockable (Nsh) vs shockable (Sh). The primary outcome was coronary angiographic evidence of acute culprit lesion, with secondary outcomes being survival to hospital discharge and neurological recovery.

RESULTS

The PEARL study included 99 patients with OHCA from a presumed cardiac etiology, 24 with nonshockable and 75 with shockable rhythms. There was no difference in the frequency of CAG between the two groups [71% (Nsh) and 75% (Sh); p = 0.79], presence of CAD [81% (Nsh) and 68% (sh); p = 0.37, or culprit lesions identified in each group [50% (Nsh) and 45% (Sh); p = 0.78. Nonshockable patients had worse discharge survival [33% (Nsh) vs 57% (Sh); p = 0.04] and those survived, had worse neurological recovery [30% (Nsh) vs 54% (Sh); p = 0.02] compared to shockable patients.

CONCLUSIONS

OHCA survivors presenting with nonshockable rhythms and no STE post resuscitation had similar prevalence of culprit coronary lesions to those with shockable rhythms. CAG may be considered in patients with OHCA without STE regardless of initial presenting rhythm. There was no benefit of emergent CAG both in shockable and non-shockable rhythms.

Mucociliary Clearance Differs in Mild Asthma by Levels of Type 2 Inflammation

BACKGROUND

Although mucus plugging is a well-reported feature of asthma, whether asthma and type 2 inflammation affect mucociliary clearance (MCC) is unknown.

RESEARCH QUESTION

Does type 2 inflammation influence mucus clearance rates in patients with mild asthma who are not receiving corticosteroids?

STUDY DESIGN AND METHODS

The clearance rates of inhaled radiolabeled particles were compared between patients with mild asthma with low (n = 17) and high (n = 18) levels of T2 inflammation. Fraction exhaled nitric oxide (Feno) was used to prospectively segregate subjects into T2 Lo (Feno < 25 ppb) and T2 Hi (Feno > 35 ppb) cohorts. Bronchial brush samples were collected with fiber-optic bronchoscopy, and quantitative polymerase chain reaction was performed to measure expression of genes associated with T2 asthma. MCC rate comparisons were also made with a historical group of healthy control subjects (HCs, n = 12).

RESULTS

The T2 Lo cohort demonstrated increased MCC when compared with both T2 Hi and historic HCs. MCC within the T2 Hi group varied significantly, with some subjects having low or zero clearance. MCC decreased with increasing expression of several markers of T2 airway inflammation (CCL26, NOS2, and POSTN) and with Feno. MUC5AC and FOXJ1 expression was similar between the T2Lo and T2Hi cohorts.

INTERPRETATION

Increasing T2 inflammation was associated with decreasing MCC. High rates of MCC in T2 Lo subjects may indicate a compensatory mechanism present in mild disease but lost with high levels of inflammation. Future studies are required to better understand mechanisms and whether impairments in MCC in more severe asthma drive worse clinical outcomes.

Diagnostic Value of FDG PET/MRI in Females With Pelvic Malignancy-A Systematic Review of the Literature

Hybrid imaging with F-18 fludeoxyglucose positron emission tomography/magnetic resonance imaging (FDG PET/MRI) has increasing clinical applications supplementing conventional ultrasound, CT, and MRI imaging as well as hybrid PET/CT imaging in assessing cervical, endometrial, and ovarian cancer. This article summarizes the existing literature and discusses the emerging role of hybrid PET/MRI in gynecologic malignancies. Thus, far, the published literature on the applications of FDG PET/MRI shows that it can have a significant impact on patient management by improving the staging of the cancers compared with PET/CT, influencing clinical decision and treatment strategy. For disease restaging, current literature indicates that PET/MRI performs equivalently to PET/CT. There appears to be a mild-moderate inverse correlation between standard-uptake-value (SUV) and apparent-diffusion-coefficient (ADC) values, which could be used to predict tumor grading and risk stratification. It remains to be seen as to whether multi-parametric PET/MRI imaging could prove valuable for prognostication and outcome. PET/MRI provides the opportunity for reduced radiation exposure, which is particularly relevant for a young female in need of multiple scans for treatment monitoring and follow-up. Fast acquisition protocols and optimized methods for attenuation correction are still evolving. Major limitations of PET/MRI remains such as suboptimal detection of small pulmonary nodules and lack of utility for radiation treatment planning, which pose an impediment in making PET/MRI a viable one-stop-shop imaging option to compete with PET/CT.

68Ga-DOTATATE PET/MRI for Neuroendocrine Tumors: A Pictorial Review

Neuroendocrine tumors (NETs) constitute a variety of neoplastic entities and exhibit variable degrees of neuroendocrine differentiation and phenotypes, as well as genetic profiles. Ga-DOTATATE PET is a novel imaging technique for NET. Although PET/CT is commonly utilized for oncologic imaging, PET/MRI is particularly suited for NETs, as MRI provides greater soft tissue contrast than CT, allowing for improved detection and characterization of NETs, particularly when liver metastasis is suspected or needs to be ruled out. The current pictorial review aims to illustrate the complementary advantages, as well as pitfalls of Ga-DOTATATE PET/MRI in the evaluation of NETs.

Multiprobe Nuclear Imaging of the Cystic Fibrosis Lung as a Biomarker of Therapeutic Effect

Background: Nuclear imaging biomarkers illustrate unique aspects of lung physiology and are useful for assessing therapeutic effects in cystic fibrosis (CF) lung disease. We have developed a multiprobe method to simultaneously measure mucociliary clearance (MCC) and paracellular absorption (ABS). MCC is a direct measure of mucus clearance. ABS has been related to airway surface liquid (ASL) absorption through previous in vitro studies. Methods: We describe baseline factors affecting MCC and ABS using data from a retrospective baseline group (n = 22) and the response of the measures to inhaled 7% hypertonic saline (HS) and dry powder mannitol using data from a prospective response group (n = 7). A retrospective healthy control group (n = 15) is also described. The baseline and control groups performed single measurements of MCC/ABS. The response group performed baseline measurements of MCC/ABS and measurements after each intervention. Results: ABS was correlated (Spearman's ρ = 0.51, p = 0.06) to sweat chloride, a systemic measure of cystic fibrosis transmembrane conductance regulator (CFTR) function, whereas MCC was not. Baseline MCC was depressed after Pseudomonas aeruginosa infection as we have previously described. MCC provided a more sensitive indication of therapeutic effect and indicated improved clearance with mannitol compared with HS. Conclusion: MCC provides a useful and well-established means of testing therapies directed at improving mucus clearance in the lung. ABS may provide a means of detecting local changes in ASL absorption and CFTR function in the lung. Both are useful tools for studying the key aspects of CF lung pathophysiology (ASL hyperabsorption and MCC depression) that link the basic genetic defects of CF to disease manifestations in the lung.

Overnight delivery of hypertonic saline by nasal cannula aerosol for cystic fibrosis

AIM

Inhaled hypertonic saline increases mucociliary clearance, improves pulmonary function, and decreases exacerbations in cystic fibrosis (CF) but contributes to the already significant treatment burden of CF. Overnight delivery of inhaled medications via a specially designed nasal cannula-aerosol device (Trans-nasal Pulmonary Aerosol Delivery [tPAD]) is an alternative approach. Here, we test whether overnight inhalation of hypertonic saline via tPAD improves mucociliary clearance and assess the tolerability of the device.

METHOD

In this study, 12 CF subjects inhaled 7% hypertonic saline (HS) for 8 h overnight using the tPAD system. Safety and tolerability were assessed and measurements of mucociliary and absorptive clearance (MCC/ABS) were performed after the treatment. Comparisons were made versus sham treatment where the same subjects wore the nasal cannula overnight but did not receive aerosol.

RESULTS

Both the HS and sham treatments were well-tolerated. Only one subject did not complete the overnight HS treatment. There were no significant differences in MCC associated with HS inhalation at any time point (90 min, 3 h, 6 h) in any lung zone. Changes in FEV₁ on both study days were similar. There were no differences in quality of sleep between HS and sham nights as assessed with the modified Leeds Sleep Evaluation Questionnaire (mLSEQ). Sino-Nasal Outcome Test (SNOT-14) questionnaires demonstrated significant increases (worsening) in 2/14 symptom categories with HS.

CONCLUSIONS

The most likely cause for the failure to accelerate MCC was under-dosing of HS relative to the active transport of salt from the airways.

Intracranial Perishunt Catheter Fluid Collections with Edema, a Sign of Shunt Malfunction: Correlation of CT/MRI and Nuclear Medicine Findings

Fluid collections with edema along the intracranial tract of ventriculoperitoneal shunt catheters in adults are rare and are more frequently seen in children. The imaging appearance of these fluid collections is frequently confusing and presents a diagnostic dilemma. We present 6 cases of adult patients noted to have collections with edema along the tract of ventriculoperitoneal shunt catheters. To our knowledge, there are no previous studies correlating the CT/MR imaging findings with nuclear medicine scans in this entity. We hypothesized that when seen in adults, the imaging findings of a CSF-like fluid collection around the intracranial ventriculoperitoneal shunt catheter on CT/MR imaging may suggest areas of CSF accumulation with interstitial edema. It is important to recognize this rare ventriculoperitoneal shunt complication in adults to prevent misdiagnosis of an abscess or cystic tumor.

Pseudomonas infection and mucociliary and absorptive clearance in the cystic fibrosis lung

Airway surface liquid hyperabsorption and mucus accumulation are key elements of cystic fibrosis lung disease that can be assessed in vivo using functional imaging methods. In this study we evaluated experimental factors affecting measurements of mucociliary clearance (MCC) and small-molecule absorption (ABS) and patient factors associated with abnormal absorption and mucus clearance.Our imaging technique utilises two radiopharmaceutical probes delivered by inhalation. Measurement repeatability was assessed in 10 adult cystic fibrosis subjects. Experimental factors were assessed in 29 adult and paediatric cystic fibrosis subjects (51 scans). Patient factors were assessed in a subgroup with optimal aerosol deposition (37 scans; 24 subjects). Paediatric subjects (n=9) underwent initial and 2-year follow-up scans. Control subjects from a previously reported study are included for comparison.High rates of central aerosol deposition influenced measurements of ABS and, to a lesser extent, MCC. Depressed MCC in cystic fibrosis was only detectable in subjects with previous Pseudomonas aeruginosa infection. Cystic fibrosis subjects without P. aeruginosa had similar MCC to control subjects. Cystic fibrosis subjects had consistently higher ABS rates.We conclude that the primary experimental factor affecting MCC/ABS measurements is central deposition percentage. Depressed MCC in cystic fibrosis is associated with P. aeruginosa infection. ABS is consistently increased in cystic fibrosis.

Improved Benefit of SPECT/CT Compared to SPECT Alone for the Accurate Localization of Endocrine and Neuroendocrine Tumors

Objective: To assess the clinical utility of SPECT/ CT in subjects with endocrine and neuroendocrine tumors compared to SPECT alone.

Material and Methods: 48 subjects (31 women;17 men; mean age 54±11) with clinical suspicion or diagnosis of endocrine and neuroendocrine tumor had 50 SPECT/CT scans (32 Tc-99m MIBI, 5 post treatment I-131, 8 In-111 Pentetreotide, and 5 I-123 MIBG). SPECT alone findings were compared to SPECT/CT and to pathology or radiological follow up.

Results: From the 32 Tc-99m MIBI scans, SPECT accurately localized the lesion in 22 positive subjects while SPECT/CT did in 31 subjects. Parathyroid lesions not seen on SPECT alone were smaller than 10 mm. In five post treatment I-131 scans, SPECT alone neither characterized, nor localized any lesions accurately. SPECT/CT revealed 3 benign etiologies, a metastatic lymph node, and one equivocal lesion. In 8 In-111 Pentetreotide scans, SPECT alone could not localize primary or metastatic lesions in 6 subjects all of which were localized with SPECT/CT. In five I-123 MIBG scans, SPECT alone could not detect a 1.1 cm adrenal lesion or correctly characterize normal physiologic adrenal uptake in consecutive scans of the same patient with prior history of adrenelectomy, all of which were correctly localized and characterized with SPECT/CT.

Conclusion: SPECT/CT is superior to SPECT alone in the assessment of endocrine and neuroendocrine tumors. It is better in lesion localization and lesion characterization leading to a decrease in the number of equivocal findings. SPECT/CT should be included in the clinical work up of all patients with diagnosis or suspicion of endocrine and neuroendocrine tumors.

Conflict of interest:None declared.

Cecal volvulus associated with intestinal malrotation presenting as postoperative intestinal obstruction

OBJECTIVE

To report a case of intestinal malrotation predisposing to cecal volvulus following nonabdominal surgery in an adult.

PRESENTATION AND INTERVENTION

A 23-year-old male with known anorectal malformation developed a postoperative intestinal obstruction following percutaneous nephrolithotomy for left renal calculus. Computed tomography of the abdomen revealed a grossly dilated cecum (9 cm) with ileocecal junction on the left side and small bowel loops on the right side of the abdomen. The patient underwent emergency exploratory laparotomy and retroperitonealization cecopexy. Bowel functions were normal at the follow-ups.

CONCLUSION

This case highlights the importance of suspecting cecal volvulus even following nonabdominal surgery in the presence of predisposing factors.

Predictors of malignancy in pancreatic head mass: a prospective study

Introduction

The objective of the study was to identify the predictive factors for malignancy in pancreatic head mass as a primary outcome and assess the value of CA 19-9 as a diagnostic tool for malignancy as a secondary outcome.

Methods

A prospective study of patients presented with pancreatic head mass was conducted in a tertiary care referral hospital, Manipal, India from May 2006 to November 2008. The study population was divided into malignant and benign groups based on the final histopathology report. A univariate and multivariate analysis of potential predictive factors for malignancy were conducted.

Results

A total of 102 patients with pancreatic head mass were included in the study after fulfilling the inclusion/exclusion criteria. 78 were malignant and 24 were benign. There was significant weight loss (p<0.001) and high mean bilirubin levels (p=0.002) in the malignant group. Mean CA 19-9 was significantly higher in the malignant group (290.7 vs. 30.3 U/ml; p<0.001). Sensitivity and specificity of CA 19-9 for detecting malignancy in pancreatic head mass at a cut off of 35U/ml was 86% and 79% respectively. CA 19-9 positivity rate was higher with increasing cut off values of 100, 200 and 300U/ml but such high levels occurred in fewer patients. All the non-jaundiced patients (100%) with raised CA 19-9 levels were found to be malignant compared to 86% malignancy in jaundiced patients. In multivariate analysis, a combination of weight loss>10% of body weight and bilirubin>3 mg/dl and CA 19-9>35U/ml had specificity and positive predictive value of 100% for predicting malignancy in pancreatic head mass.

Conclusion

The presence of weight loss and jaundice and raised CA 19-9 levels together in a patient with pancreatic head mass can be predictive of malignancy. A very high CA 19-9 level can be an indicator of malignancy in a pancreatic head mass. A raised CA 19-9 level may be more predictive of malignancy in non-jaundiced patients than in jaundiced patients.

Myelofibrosis on 18F-FDG-PET/CT in a case suspicious for post-transplant lymphoproliferative disorder

Recent studies have advocated the utility of fluorine-18 fluorodeoxyglucose-positron emission tomography (18)F-FDG-PET imaging in evaluation of various hematological disorders. We report a case of a 61-year-old man with clinical suspicion of post-transplant lymphoproliferative disorder (PTLD) where (18)F-FDG-PET/CT (computerized tomography) was helpful in identifying myelofibrosis. This paper aims to reveal the potential diagnostic value of PET/CT as an imaging modality in the evaluation of myelofibrosis.

Absorptive clearance of DTPA as an aerosol-based biomarker in the cystic fibrosis airway

Biomarkers providing in vivo quantification of the basic elements of cystic fibrosis (CF) lung disease are needed. A study was performed to determine whether the absorption of a small radiolabelled hydrophilic molecule (Indium-111 (In-)DTPA) would be increased in CF airways. DTPA clearance has been used previously to assess epithelial permeability and may also be useful for quantifying liquid absorption. The absorptive clearance rate of DTPA was quantified in 10 CF and 11 control subjects using a novel aerosol technique. Subjects inhaled an aerosol containing nonabsorbable technetium-99m sulfur colloid (Tc-SC) particles and In-DTPA. Tc-SC clearance from the lung is exclusively mucociliary, while In-DTPA is cleared by both absorption and mucociliary clearance. The difference between the In-DTPA and Tc-SC clearance rates estimates In-DTPA absorption. Tc-SC (mucociliary) clearance was similar in central and peripheral zones in CF and non-CF lungs. Total In-DTPA clearance was increased in both zones in CF lungs. The absorptive component of In-DTPA clearance was increased in the airway-dominated central lung zones in CF (42% x h( -1) versus 32% x h(-1), p = 0.03). The absorption of In-DTPA is increased in the CF airway. Further study is needed to understand the relative roles of fluid absorption, inflammation and other mechanisms potentially affecting epithelial permeability and DTPA absorption.

Intratumoral epidermal growth factor receptor antisense DNA therapy in head and neck cancer: first human application and potential antitumor mechanisms

PURPOSE

Squamous cell carcinoma of the head and neck (SCCHN) is characterized by upregulation of the epidermal growth factor receptor (EGFR). We developed a novel strategy to target EGFR by using a therapeutic gene that consisted of an EGFR antisense (AS) gene sequence under U6 promoter control. A phase I clinical trial was conducted to evaluate the safety and biologic effects of EGFR AS.

PATIENTS AND METHODS

Patients with advanced SCCHN who were refractory to standard therapies and who had at least one assessable and accessible lesion were enrolled. The EGFR AS dose was escalated in successive cohorts (six dose levels; 60 to 1,920 microg/injection). Patients received four weekly intratumoral EGFR AS injections. Tumor biopsies were performed before and after completion of therapy. Treatment response was assessed by tumor volume measurements (positron emission tomography/computed tomography), and levels of target proteins were assessed by immunohistochemistry.

RESULTS

Seventeen assessable patients were treated. No grades 3 to 4 or dose-limiting toxicities were noted, and a maximum-tolerated dose was not reached. Five patients (29%) achieved a clinical response, which included two complete responses (CRs) and three partial responses (PRs); two additional patients had stable disease (SD) as the best response. Patients with disease control (CR + PR + SD) had tumors with higher EGFR and lower STAT3 expression at baseline compared with patients who had progressive disease (P = .0312 and P = .095, respectively).

CONCLUSION

Intratumoral EGFR AS was safe and resulted in antitumor activity in patients with advanced SCCHN. Baseline levels of high EGFR and low STAT3 may be associated with antitumor effects.

Interpretability of PET/CT imaging in head and neck cancer patients following composite mandibular resection and osteocutaneous free flap reconstruction

BACKGROUND

We investigated positron emission tomography (PET)/CT scanning following segmental resections and osteocutaneous free-flap reconstruction. The interpretability of PET/CT imaging with healing osteotomies and reconstruction hardware was analyzed.

METHODS

Patient scans within 18 months of surgery were interpreted for malignancy. Interpretations were compared with clinical data to determine sensitivity/specificity. Standardized uptake values (SUVs) were determined for bony controls, osteotomies, and tumors and were analyzed using paired t test.

RESULTS

Fifteen scans were visually interpreted, 13 underwent SUV analysis. Reconstruction hardware did not interfere with interpretability. Sensitivity and specificity were 88% and 86%, respectively. Osteotomy sites averaged 25% higher SUVs compared with bony controls (vs sternum p = .003, vs mandible p = .008). Tumor SUVs were higher than osteotomies (p = .023) and controls (vs sternum p = .013, vs mandible p = .025).

CONCLUSION

Although osteotomies were characterized by an increased fluorodeoxyglucose signal, scan interpretability was unimpaired. Our study suggests that PET/CT imaging can be utilized to survey free-flap patients at acceptable levels of sensitivity/specificity.

Delayed development of radiation vasculopathy of the brain stem confirmed by F-18 FDG PET in a case of anaplastic astrocytoma

We present the imaging findings of a 38-year-old female patient who underwent resection and radiation therapy for an anaplastic astrocytoma in her left temporal lobe 12 years ago. She was symptom-free until 1 month before admission at which time she presented with symptoms of right hemiparesis, right facial droop, and slurred speech. Magnetic resonance imaging (MRI) of the brain showed a new mass lesion in the left pontine region of the brain stem. Magnetic resonance spectroscopy imaging of the lesion demonstrated an increase in choline (Ch)/N-acetyl aspartate (NAA) metabolite values which were nondiagnostic. Since viable tumor recurrence was strongly suspected, a biopsy was planned, although this posed significant risk. Therefore, an F-18 FDG brain PET scan was performed, which demonstrated no metabolic activity in the pontine lesion leading to the less common diagnosis of long-term postradiation vasculopathy. Over the next 6 months, the patient's symptoms slowly improved and a follow-up MRI scan showed a decrease in the size of the lesion, consistent with postradiation vasculopathy and infarction. This case illustrates the importance of considering the rare diagnosis of radiation-induced vasculopathy in the differential diagnosis when symptoms of recurrent brain tumor occur.

Evaluation of a system for grading the complexity of root canal treatment

AIM

To evaluate the reproducibility of the Restorative Index of Treatment Need (RIOTN) system for grading the complexity of root canal treatment.

METHODOLOGY

The RIOTN system of grading the complexity of root canal treatment was applied to all endodontic referrals to a department of restorative dentistry in a district general hospital within a period of one year. Grading was repeated in 60 randomly selected teeth and weighted kappa analysis was used to test for intra-observer as well as inter-observer agreement with a consultant in restorative dentistry and a vocational trainee (VT).

RESULTS

In all, 152 patients were referred for root canal treatment of 186 teeth within the period of study. Weighted kappa for intra-observer agreement when categorising complexity was 0.636. Weighted kappa for inter-observer agreement with the consultant was 0.570 and that for agreement with the VT was 0.223.

CONCLUSION

The RIOTN system of grading the complexity of root canal treatment was incomplete; with moderate to poor reproducibility.

Quantum lithography with classical light

We show how to achieve subwavelength diffraction and imaging with classical light, previously thought to require quantum fields. By correlating wave vector and frequency in a narrow band, multiphoton detection process that uses Doppleron-type resonances, we show how to achieve arbitrary focal and image plane patterning with classical laser light at submultiples of the Rayleigh limit, with high efficiency, visibility, and spatial coherence. A frequency-selective measurement process thus allows one to simulate, semiclassically, the path-number correlations that distinguish a quantum entangled field.

Differential capacitance of liquid/liquid interfaces--a lattice gas model approach

A lattice gas model formalism under mean field approximation is developed for the analysis of differential capacitance pertaining to liquid/liquid interfaces. The interfacial profiles for the two solvent mole fractions are chosen and ionic charge densities are estimated by minimizing the Helmholtz free energy. The dependence of the differential capacitance on various interaction energies, electrolyte concentrations and dielectric constants is indicated. The influence of the solvent density profile is analyzed and deviations from the predictions of Gouy-Chapman theory are pointed out.

Inducing disallowed two-atom transitions with temporally entangled photons

Two uncoupled two-level atoms cannot be jointly excited by classical light under general circumstances, due to destructive interference of excitation pathways in two-photon absorption. However, with temporally entangled light, two-atom excitation is shown possible. Photons arising from three-level cascade decay are intrinsically ordered in time of emission. This field correlation induces a joint resonance in the two-atom excitation probability via suppression of one of the time-ordered excitation pathways. The relative gain in two-photon absorption increases with the time-frequency entanglement.

An assessment of the management of patients on warfarin by general dental practitioners in South West Wales

For anticoagulation therapy, warfarin is used to reduce the risk of thrombo-embolic events in patients with mechanical prosthetic heart valves, certain cardiovascular conditions, deep vein thrombosis (DVT) and hypercoagulable states.(1). The International Normalised Ratio (INR) is used as a measure of anticoagulation and is expressed as a ratio of the patient's prothrombin time (PT) to control prothrombin time. In a person with a normal PT, the INR is approximately 1. The therapeutic range is the value of INR or degree of anticoagulation required to prevent the development of serious thrombo-embolism and is normally maintained between 2.0 and 4.5. It is important to recognize that the INR is only valid for patients on well controlled anticoagulant therapy, ie where the level of anticoagulation is reasonably stable over a moderate length of time.(2).

Afferent loop syndrome: the role of Tc-99m mebrofenin hepatobiliary scintigraphy

Afferent loop syndrome is caused by intermittent mechanical obstruction of the afferent loop of a gastrojejunostomy and may present early as an acute type or late as a chronic type. The authors describe two patients who were examined for a history of bilious vomiting after gastrojejunostomy, and who were thought to have afferent loop syndrome (chronic type) based on clinical findings. Results of routine investigations, such as upper gastrointestinal endoscopy, and ultrasonography were inconclusive. Findings from the barium meal follow-through studies were normal in the first patient and revealed a dilated duodenum in the second patient. Tc-99m bromotriethyl-iminodiacetic acid has been used to identify afferent loop obstruction as represented in these studies.

An audit of antibiotic prescribing by general practitioners in the initial management of acute dental infection

A sub-regional audit showed a high rate of referral of acute dentoalveolar infections as emergencies. In Torbay Hospital alone, 21 patients required admission following such referrals in a period of 3 months. A questionnaire was therefore sent out to all general medical and general dental practitioners in the area covered by Torbay Hospital in order to survey their choice of antibiotics in the initial management of acute dentoalveolar infections. The results showed that the prescribing patterns of general medical practitioners differed significantly from those of general dental practitioners and that practitioners were reluctant to prescribe metronidazole as a first choice, even in patients allergic to penicillin. The authors conclude that awareness about the use of antibiotics, particularly among general dental practitioners, needs to be increased.