Characterising 18F-fluciclovine uptake in breast cancer through the use of dynamic PET/CT imaging

BACKGROUND

18F-fluciclovine is a synthetic amino acid positron emission tomography (PET) radiotracer that is approved for use in prostate cancer. In this clinical study, we characterised the kinetic model best describing the uptake of 18F-fluciclovine in breast cancer and assessed differences in tracer kinetics and static parameters for different breast cancer receptor subtypes and tumour grades.

METHODS

Thirty-nine patients with pathologically proven breast cancer underwent 20-min dynamic PET/computed tomography imaging following the administration of 18F-fluciclovine. Uptake into primary breast tumours was evaluated using one- and two-tissue reversible compartmental kinetic models and static parameters.

RESULTS

A reversible one-tissue compartment model was shown to best describe tracer uptake in breast cancer. No significant differences were seen in kinetic or static parameters for different tumour receptor subtypes or grades. Kinetic and static parameters showed a good correlation.

CONCLUSIONS

18F-fluciclovine has potential in the imaging of primary breast cancer, but kinetic analysis may not have additional value over static measures of tracer uptake.

CLINICAL TRIAL REGISTRATION

NCT03036943.

Comparative accuracy and cost-effectiveness of dynamic contrast-enhanced CT and positron emission tomography in the characterisation of solitary pulmonary nodules

INTRODUCTION

Dynamic contrast-enhanced CT (DCE-CT) and positron emission tomography/CT (PET/CT) have a high reported accuracy for the diagnosis of malignancy in solitary pulmonary nodules (SPNs). The aim of this study was to compare the accuracy and cost-effectiveness of these.

METHODS

In this prospective multicentre trial, 380 participants with an SPN (8-30 mm) and no recent history of malignancy underwent DCE-CT and PET/CT. All patients underwent either biopsy with histological diagnosis or completed CT follow-up. Primary outcome measures were sensitivity, specificity and overall diagnostic accuracy for PET/CT and DCE-CT. Costs and cost-effectiveness were estimated from a healthcare provider perspective using a decision-model.

RESULTS

312 participants (47% female, 68.1±9.0 years) completed the study, with 61% rate of malignancy at 2 years. The sensitivity, specificity, positive predictive value and negative predictive values for DCE-CT were 95.3% (95% CI 91.3 to 97.5), 29.8% (95% CI 22.3 to 38.4), 68.2% (95% CI 62.4% to 73.5%) and 80.0% (95% CI 66.2 to 89.1), respectively, and for PET/CT were 79.1% (95% CI 72.7 to 84.2), 81.8% (95% CI 74.0 to 87.7), 87.3% (95% CI 81.5 to 91.5) and 71.2% (95% CI 63.2 to 78.1). The area under the receiver operator characteristic curve (AUROC) for DCE-CT and PET/CT was 0.62 (95% CI 0.58 to 0.67) and 0.80 (95% CI 0.76 to 0.85), respectively (p<0.001). Combined results significantly increased diagnostic accuracy over PET/CT alone (AUROC=0.90 (95% CI 0.86 to 0.93), p<0.001). DCE-CT was preferred when the willingness to pay per incremental cost per correctly treated malignancy was below £9000. Above £15 500 a combined approach was preferred.

CONCLUSIONS

PET/CT has a superior diagnostic accuracy to DCE-CT for the diagnosis of SPNs. Combining both techniques improves the diagnostic accuracy over either test alone and could be cost-effective.

TRIAL REGISTRATION NUMBER

NCT02013063.

Chest CT screening for COVID-19 in elective and emergency surgical patients: experience from a UK tertiary centre

AIM

To determine the incidence of possible COVID-19-related lung changes on preoperative screening computed tomography (CT) for COVID-19 and how their findings influenced decision-making. To also to determine whether the patients were managed as COVID-19 patients after their imaging findings, and the proportion who had SARS-CoV2 reverse transcriptionpolymerase chain reaction (RT-PCR) testing.

MATERIALS AND METHODS

A retrospective study was undertaken of consecutive patients having imaging prior to urgent elective surgery (n=156) or acute abdominal imaging (n=283). Lung findings were categorised according to the British Society of Thoracic Imaging (BSTI) guidelines. RT-PCR testing, management, and outcomes were determined from the electronic patient records.

RESULTS

3% (13/439) of CT examinations demonstrated findings of classic/probable COVID-19 pneumonia, whilst 4% (19/439) had findings indeterminate for COVID-19. Of the total cohort, 1.6% (7/439) subsequently had confirmed RT-PCR-positive COVID-19. Importantly, all the patients with a normal chest or alternative diagnoses on CT who had PCR testing within the next 7 days, had a negative RT-PCR (92/407). There was a change in surgical outcome in 6% (10/156) of the elective surgical cohort with no change to surgical management was demonstrated in the acute abdominal emergency cohort requiring surgery (2/283).

CONCLUSION

There was a 7% (32/439) incidence of potential COVID-19-related lung changes in patients having preoperative CT. Although this altered surgical management in the elective surgical cohort, no change to surgical management was demonstrated in the acute abdominal emergency cohort requiring surgery.

Multi-observer concordance and accuracy of the British Thoracic Society scale and other visual assessment qualitative criteria for solid pulmonary nodule assessment using FDG PET-CT

AIM

To compare the interobserver reliability and diagnostic accuracy of the British Thoracic Society (BTS) scale and other visual assessment criteria in the context of 2-[¹⁸F]-fluoro-2-deoxy-d-glucose (FDG) positron-emission tomography (PET)-computed tomography (CT) evaluation of solid pulmonary nodules (SPNs).

MATERIALS AND METHODS

Fifty patients who underwent FDG PET-CT for assessment of a SPN were identified. Seven reporters with varied experience at four centres graded FDG uptake visually using the British Thoracic Society (BTS) four-point scale. Five reporters also scored SPNs according to three- and five-point visual assessment scales and using semi-quantitative assessment (maximum standardised uptake value [SUV_max]). Interobserver reliability was assessed with the intra-class correlation coefficient (ICC) and weighted Cohen's kappa (κ). Diagnostic performance was evaluated by receiver operator characteristic (ROC) analysis.

RESULTS

Good interobserver reliability was demonstrated with the BTS scale (ICC=0.78, 95% confidence interval [CI]: 0.69-0.85) and five-point scale (ICC=0.78, 95 CI 0.68-0.86), whilst the three-point scale demonstrated moderate reliability (ICC=0.70, 95% CI: 0.59-0.80). Almost perfect agreement was achieved between two consultants (κ=0.85), and substantial agreement between two other consultants (κ=0.78) using the BTS scale. ROC curves for the BTS and five-point scales demonstrated equivalent accuracy (BTS area under the ROC curve [AUC]=0.768; five-point AUC=0.768). SUV_max was no more accurate compared to the BTS scale (SUV_max AUC=0.794; BTS AUC=0.768, p=0.43).

CONCLUSIONS

The BTS scale can be applied reliably by reporters with varied levels of PET-CT reporting experience, across different centres and has a diagnostic performance that is not surpassed by alternative scales.

Is microwave ablation more effective than radiofrequency ablation in achieving local control for primary pulmonary malignancy?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was 'Is microwave ablation (MWA) more effective than radiofrequency ablation (RFA) in achieving local control for primary lung cancer?'. Altogether, 439 papers were found, of which 7 represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Both are thermal ablative techniques, with microwave ablation (MWA) the newer technique and radiofrequency ablation (RFA) with a longer track record. Lack of consensus with regard to definitions of technical success and efficacy and heterogeneity of study inclusions limits studies for both. The only direct comparison study does not demonstrate a difference with either technique in achieving local control. The quality of evidence for MWA is very limited by retrospective nature and heterogeneity in technique, power settings and tumour type. Tumour size and late-stage cancer were shown to be associated with higher rates of local recurrence in 1 MWA study. RFA studies were generally of a higher level of evidence comprising prospective trials, systematic review and meta-analysis. The recurrence rates for MWA and RFA overlapped, and for the included studies ranged between 16% and 44% for MWA and 9% and 58% for RFA. The current evidence, therefore, does not clearly demonstrate a benefit of MWA over RFA in achieving local control in primary lung cancer.

18Fluorocholine PET/CT scanning with arterial phase-enhanced CT is useful for persistent/recurrent primary hyperparathyroidism: first UK case series results

INTRODUCTION

Redo parathyroidectomy for persistent/recurrent primary hyperparathyroidism is associated with a higher risk of complications and should be planned only with convincing localisation. We assessed whether ¹⁸fluorocholine positron emission tomography/computed tomography could identify parathyroid adenoma(s) in patients with persistent/recurrent primary hyperparathyroidism and negative conventional scans.

MATERIALS AND METHODS

A departmental database was used to identify patients with failed localisation attempts (sestamibi single photon emission computed tomography/computed tomography and/or computed tomography/magnetic resonance imaging and/or selective parathyroid hormone sampling) after previous unsuccessful surgery for primary hyperparathyroidism. ¹⁸Fluorocholine positron emission tomography was performed in all patients and redo surgery offered to those with positive findings.

RESULTS

¹⁸Fluorocholine positron emission tomography incorporating arterial and portal phase enhanced computed tomography was performed in 12 patients with persistent/recurrent primary hyperparathyroidism (four men and eight women). Seven patients (58%) were cured after excision of adenomas located in ectopic positions (n = 3) or in anatomical position (n = 4). Five patients (42%) had persistent hypercalcaemia and repeat ¹⁸fluorocholine scan confirmed that the area highlighted on preoperative scans was excised. The arterial phase enhancement of the computed tomography was significantly different between cured and not-cured patients (P = 0.007). All seven cured patients had either a strong or weak enhancing pattern on computed tomography. Standardised uptake value at 60 minutes in patients with successful surgery (range 2.7-15.7, median 4.05) was higher than in patients with failed surgery (range 1.8-5.8, median 3.2) but was not statistically significant (P = 0.300).

DISCUSSION

¹⁸fluorocholine scanning can identify elusive parathyroid adenomas, including those that are ectopic, and is useful in the management of patients with persistent/recurrent primary hyperparathyroidism when first-line scans are negative. The grading of the arterial phase of computed tomography can help to differentiate between true adenomas and false positive targets (lymph nodes).

Metabolic nodal response as a prognostic marker after neoadjuvant therapy for oesophageal cancer

BACKGROUND

The ability to predict recurrence and survival after neoadjuvant chemotherapy (NAC) and surgery for oesophageal cancer remains elusive. This study evaluated the role of [18 F]fluorodeoxyglucose (FDG) PET-CT in assessing tumour and nodal response as a prognostic marker.

METHODS

This was a single-centre UK cohort study. From 2006 to 2014, patients with oesophageal cancer staged with PET-CT before NAC, and restaged by CT or PET-CT before resection, were included. Pathological tumour response was evaluated using Mandard regression grades. Metabolic tumour and nodal responses (mTR and mNR respectively) were quantified using absolute and threshold reductions.

RESULTS

Among 294 included patients, mTR and mNR independently predicted prognosis before surgery. After surgery, mNR (but not mTR), pathological tumour response, resection margin status and pathological node category predicted prognosis. Patients with FDG-avid nodal disease after NAC were at high risk of recurrence/death at 1 and 2 years (43 and 71 per cent respectively; P = 0·030 and P = 0·025 versus patients without avid nodes), and had a worse prognosis than patients with non-avid nodal metastases: hazard ratio 4·19 (95 per cent c.i. 1·87 to 9·40) and 2·11 (1·12 to 3·97) respectively versus patients without nodal metastases. Considering mTR and mNR response separately improved prognostication.

CONCLUSION

mNR is a novel prognostic factor, independent of conventional N status. Primary and nodal tumours may respond discordantly and patients with FDG-avid nodes after NAC have a poor prognosis.

State-of-the-art: Radiological investigation of pleural disease

Pleural disease is common. Radiological investigation of pleural effusion, thickening, masses, and pneumothorax is key in diagnosing and determining management. Conventional chest radiograph (CXR) remains as the initial investigation of choice for patients with suspected pleural disease. When abnormalities are detected, thoracic ultrasound (US), computed tomography (CT), magnetic resonance imaging (MRI) and positron emission tomography (PET) can each play important roles in further investigation, but appropriate modality selection is critical. US adds significant value in the identification of pleural fluid and pleural nodularity, guiding pleural procedures and, increasingly, as "point of care" assessment for pneumothorax, but is highly operator dependent. CT scan is the modality of choice for further assessment of pleural disease: Characterising pleural thickening, some pleural effusions and demonstration of homogeneity of pleural masses and areas of fatty attenuation or calcification. MRI has specific utility for soft tissue abnormalities and may have a role for younger patients requiring follow-up serial imaging. MRI and PET/CT may provide additional information in malignant pleural disease regarding prognosis and response to therapy. This article summarises existing techniques, highlighting the benefits and applications of these different imaging modalities and provides an up to date review of the evidence.

Does perfusion CT play a role in the evaluation of percutaneous microwave-ablated lung tumours?

AIM

To assess the clinical utility of perfusion computed tomography (pCT) parameters in microwave ablation (MWA) of lung tumours.

MATERIALS AND METHODS

Patients were included who had primary or metastatic lung tumours and underwent pCT studies immediately pre- and post-MWA. Perfusion maps of the tumours were constructed using CT perfusion software (GE, Milwaukee, WI, USA). Regions of interest were drawn on sequential axial sections to extract the pCT parameters, blood volume (BV), average blood flow (BF), and mean transit time (MTT) from the entire tumour volume. Direct visualisation of perfusion maps were performed by two experienced readers blinded to outcome. Data were analysed using the Mann-Whitney test.

RESULTS

Thirty-one patients with 34 lung tumours had follow-up data at 12 months. The median tumour diameter was 19 mm (10-52 mm). Seven patients developed local tumour progression (LTP) at 12 months. There was no statistical difference between patients with LTP and complete treatment based on quantitative pCT parameters. Using radiologist visualisation of perfusion maps, there was moderate agreement between the two readers (kappa coefficient 0.53) with a combined 96% sensitivity, 62% specificity, 91% positive predictive value, and 80% negative predictive value.

CONCLUSION

Quantitative pCT parameters do not help differentiate between LTP and complete treatment, but subjective analysis of perfusion maps may be a useful assessment tool for identifying treatment adequacy potentially enabling identification of areas requiring further treatment at the time of the procedure.

Accuracy and cost-effectiveness of dynamic contrast-enhanced CT in the characterisation of solitary pulmonary nodules-the SPUtNIk study

INTRODUCTION

Solitary pulmonary nodules (SPNs) are common on CT. The most cost-effective investigation algorithm is still to be determined. Dynamic contrast-enhanced CT (DCE-CT) is an established diagnostic test not widely available in the UK currently.

METHODS AND ANALYSIS

The SPUtNIk study will assess the diagnostic accuracy, clinical utility and cost-effectiveness of DCE-CT, alongside the current CT and 18-flurodeoxyglucose-positron emission tomography) (18FDG-PET)-CT nodule characterisation strategies in the National Health Service (NHS). Image acquisition and data analysis for 18FDG-PET-CT and DCE-CT will follow a standardised protocol with central review of 10% to ensure quality assurance. Decision analytic modelling will assess the likely costs and health outcomes resulting from incorporation of DCE-CT into management strategies for patients with SPNs.

ETHICS AND DISSEMINATION

Approval has been granted by the South West Research Ethics Committee. Ethics reference number 12/SW/0206. The results of the trial will be presented at national and international meetings and published in an Health Technology Assessment (HTA) Monograph and in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ISRCTN30784948; Pre-results.

High-frequency jet ventilation under general anesthesia facilitates CT-guided lung tumor thermal ablation compared with normal respiration under conscious analgesic sedation

PURPOSE

To determine whether technical difficulty of computed tomography (CT)-guided percutaneous lung tumor thermal ablations is altered with the use of high-frequency jet ventilation (HFJV) under general anesthesia (GA) compared with procedures performed with normal respiration (NR) under conscious sedation (CS).

MATERIALS AND METHODS

Thermal ablation treatment sessions performed with NR under CS or HFJV under GA with available anesthesia records and CT fluoroscopic images were retrospectively reviewed; 13 and 33 treatment sessions, respectively, were identified. One anesthesiologist determined the choice of anesthesiologic technique independently. Surrogate measures of procedure technical difficulty--time duration, number of CT fluoroscopic acquisitions, and radiation dose required for applicator placement for each tumor--were compared between anesthesiologic techniques. The anesthesiologist time and complications were also compared. Parametric and nonparametric data were compared by Student independent-samples t test and χ(2) test, respectively.

RESULTS

Patients treated with HFJV under GA had higher American Society of Anesthesiologists classifications (mean, 2.66 vs 2.23; P = .009) and smaller lung tumors (16.09 mm vs 27.38 mm; P = .001). The time duration (220.30 s vs 393.94 s; P = .008), number of CT fluoroscopic acquisitions (10.31 vs 19.13; P = .023), and radiation dose (60.22 mGy·cm vs 127.68 mGy·cm; P = .012) required for applicator placement were significantly lower in treatment sessions performed with HFJV under GA. There was no significant differences in anesthesiologist time (P = .20), rate of pneumothorax (P = .62), or number of pneumothoraces requiring active treatment (P = .19).

CONCLUSIONS

HFJV under GA appears to reduce technical difficulty of CT-guided percutaneous applicator placement for lung tumor thermal ablations, with similar complication rates compared with treatment sessions performed with NR under CS. The technique is safe and may facilitate treatment of technically challenging tumors.

A computer-aided algorithm to quantitatively predict lymph node status on MRI in rectal cancer

OBJECTIVE

The aim of this study was to demonstrate the principle of supporting radiologists by using a computer algorithm to quantitatively analyse MRI morphological features used by radiologists to predict the presence or absence of metastatic disease in local lymph nodes in rectal cancer.

METHODS

A computer algorithm was developed to extract and quantify the following morphological features from MR images: chemical shift artefact; relative mean signal intensity; signal heterogeneity; and nodal size (volume or maximum diameter). Computed predictions on nodal involvement were generated using quantified features in isolation or in combinations. Accuracies of the predictions were assessed against a set of 43 lymph nodes, determined by radiologists as benign (20 nodes) or malignant (23 nodes).

RESULTS

Predictions using combinations of quantified features were more accurate than predictions using individual features (0.67-0.86 vs 0.58-0.77, respectively). The algorithm was more accurate when three-dimensional images were used (0.58-0.86) than when only middle image slices (two-dimensional) were used (0.47-0.72). Maximum node diameter was more accurate than node volume in representing the nodal size feature; combinations including maximum node diameter gave accuracies up to 0.91.

CONCLUSION

We have developed a computer algorithm that can support radiologists by quantitatively analysing morphological features of lymph nodes on MRI in the context of rectal cancer nodal staging. We have shown that this algorithm can combine these quantitative indices to generate computed predictions of nodal status which closely match radiological assessment. This study provides support for the feasibility of computer-assisted reading in nodal staging, but requires further refinement and validation with larger data sets.

Role of positron emission tomography-computed tomography in predicting survival after neoadjuvant chemotherapy and surgery for oesophageal adenocarcinoma

BACKGROUND

Positron emission tomography combined with computed tomography (PET-CT) is increasingly being used in the staging of oesophageal cancer. Some recent reports suggest it may be used to predict survival. None of these studies, however, reported on the prognostic value of PET-CT performed before neoadjuvant chemotherapy and surgery. The aim of this study was to determine whether pretreatment PET-CT could predict survival.

METHODS

Consecutive patients with oesophageal adenocarcinoma who underwent PET-CT before neoadjuvant chemotherapy and resection were included. Maximum standardized uptake value (SUV(max)), fluorodeoxyglucose (FDG)-avid tumour length and the presence of FDG-avid local lymph nodes were determined for all patients. Kaplan-Meier survival analysis was performed and multivariable analysis used to identify independent prognostic factors.

RESULTS

A total of 121 patients were included (mean age 63 years, 97 men) of whom 103 underwent surgical resection. On an intention-to-treat basis, overall survival was significantly worse in patients with FDG-avid local lymph nodes (P < 0·001). SUV(max) and FDG-avid tumour length did not predict survival (P = 0·276 and P = 0·713 respectively). The presence of FDG-avid local lymph nodes was an independent predictor of poor overall survival (hazard ratio (HR) 4·75, 95 per cent confidence interval 2·14 to 10·54; P < 0·001) and disease-free survival (HR 2·97, 1·40 to 6·30; P = 0·004).

CONCLUSION

The presence of FDG-avid lymph nodes, but not SUV(max) or FDG-avid tumour length, was an independent adverse prognostic factor.

MRI features of the complete histopathological response of locally advanced rectal cancer to neoadjuvant chemoradiotherapy

AIM

To describe the post-chemoradiotherapy magnetic resonance imaging (MRI) features of locally advanced rectal carcinoma (LARC) in which there has been a complete histopathological response to neoadjuvant chemoradiotherapy (CRT).

MATERIALS AND METHODS

This retrospective cohort study was performed between January 2005 and November 2009 at a regional cancer centre. Consecutive patients with LARC and a histopathological complete response to long-course CRT were identified. Pre- and post-treatment MRI images were reviewed using a proforma for predefined features and response criteria. ymrT0 was defined as the absence of residual abnormality on MRI.

RESULTS

Twenty patients were included in the study. Seven (35%) ypT0 tumours were ymrT0. All 13 ypT0 tumours not achieving ymrT0 appearances had a good radiological response, with at least 65% tumour reduction. The appearances were heterogeneous: in 11/13 patients the tumour was replaced by a region of at least 50% low signal on MRI, with 8/13 having ≥80% low signal, and 3/13 with 100% low signal.

CONCLUSION

MRI may be useful in identifying a complete histopathological response. However, the MRI appearances of ypT0 tumours are heterogeneous and conventional MRI complete response criteria will not detect the majority of patients with a complete histopathological response.

Thoracic ultrasound in the diagnosis of malignant pleural effusion

BACKGROUND

Malignant pleural effusion (MPE) is a common clinical problem with described investigation pathways. While thoracic ultrasound (TUS) has been shown to be accurate in pleural fluid detection, its use in the diagnosis of malignant pleural disease has not been assessed. A study was undertaken to assess the diagnostic accuracy of TUS in differentiating malignant and benign pleural disease.

METHODS

52 consecutive patients with suspected MPE underwent TUS and contrast-enhanced CT (CECT). TUS was used to assess pleural surfaces using previously published CT imaging criteria for malignancy, diaphragmatic thickness/nodularity, effusion size/nature and presence of hepatic metastasis (in right-sided effusions). A TUS diagnosis of malignant or benign disease was made blind to clinical data/other investigations by a second blinded operator using anonymised TUS video clips. The TUS diagnosis was compared with the definitive clinical diagnosis and in addition to the diagnosis found at CECT.

RESULTS

A definitive malignant diagnosis was based on histocytology (30/33; 91%) and clinical/CT follow-up (3/33; 9%). Benign diagnoses were based on negative histocytology and follow-up over 12 months in 19/19 patients. TUS correctly diagnosed malignancy in 26/33 patients (sensitivity 73%, specificity 100%, positive predictive value 100%, negative predictive value 79%) and benign disease in 19/19. Pleural thickening >1 cm, pleural nodularity and diaphragmatic thickening >7 mm were highly suggestive of malignant disease.

CONCLUSION

TUS is useful in differentiating malignant from benign pleural disease in patients presenting with suspected MPE and may become an important adjunct in the diagnostic pathway.

The diagnosis and management of pleural empyema

The diagnosis and management of pleural infection continues to improve steadily. Recent advances include: newer, smaller, and more comfortable chest drainage catheters; improved pleural pus drainage with the aid of intrapleural fibrinolytics; and improved surgical procedures including thoracoscopic surgery. The optimal size of chest drainage tube remains a matter of debate, with no large data sets available to clarify the optimal tube size. In contrast, there are now small controlled trials of sound basic methodology which suggest a therapeutic role for both fibrinolytics and thoracoscopy. Studies large enough to establish clearly the efficacy and safety of these approaches are now at the planning and recruitment stage.

Perfusion scintigraphy: diagnostic utility in pregnant women with suspected pulmonary embolic disease

Pulmonary embolism (PE) is a major preventable cause of maternal mortality during pregnancy and accurate diagnosis is essential. Computed tomography pulmonary angiography (CTPA) is a robust diagnostic test in non-pregnant patients with suspected PE. The potential latent carcinogenic effects of CTPA-related breast irradiation mandates careful use of this technique in young women. The aim of this study was to determine the efficacy of perfusion scintigraphy as the first line investigation in pregnant women with suspected PE. All pregnant women referred for radiological investigation of suspected PE in a 5-year period from January 2001 to December 2005 were included. Demographic data and imaging studies were reviewed. Subsequent pregnancy outcome was determined by case note review. One hundred and five consecutive patients had either perfusion scintigraphy (Q scan) (n = 94), CTPA (n = 9) or both (n = 2), one patient presented twice. Q scans were the first line investigation in 96 (91%) patients. Eighty-nine (92%) scans were normal, seven (7%) were non-diagnostic and one (1%) was high probability. One patient had a thromboembolic event 3 weeks post partum. No adverse events were reported during the follow-up period. Pulmonary embolic disease is uncommon in pregnancy. Perfusion scintigraphy in pregnant patients has an excellent diagnostic yield. The percentage of non-diagnostic scans is much lower than in other patient groups. Scintigraphy imparts a significantly lower breast dose than CTPA and should be used as the first-line investigation in most pregnant patients with suspected PE.

Minimally invasive parathyroidectomy without intraoperative parathyroid hormone monitoring in patients with primary hyperparathyroidism

BACKGROUND

Minimally invasive parathyroidectomy (MIP) is the preferred operation for patients with primary hyperparathyroidism (HPT) and positive preoperative imaging. This non-randomized case series assessed the long-term results of MIP performed without the use of intraoperative parathyroid hormone (ioPTH) monitoring.

METHODS

The study involved prospective collection of demographic, biochemical and operative details on a consecutive, unselected cohort of 298 patients who underwent surgery for non-familial primary HPT during a 5-year interval. The mean preoperative serum calcium level was 3.00 mmol/l with a mean parathyroid hormone concentration of 25.8 pmol/l. (99m)Tc-labelled sestamibi scanning and neck ultrasonography were performed in 262 patients.

RESULTS

Sestamibi scan showed unilateral uptake in 182 patients and a single parathyroid adenoma was confirmed on ultrasonography in 161 patients. MIP was performed in 150 patients. The mean duration of operation was 25 (range 8-65) min. Four patients needed conversion to conventional neck exploration. There was one postoperative haematoma and three cases of temporary recurrent laryngeal nerve neuropraxia. All but four patients were normocalcaemic after MIP. All the parathyroid tumours removed were adenomas, with a mean weight of 1.3 (range 0.1-17.4) g. No patient developed recurrent HPT after a median follow-up of 16 (range 3-48) months.

CONCLUSION

The outcome of MIP without ioPTH monitoring was comparable to that reported in series that used ioPTH monitoring.

Improving the diagnostic performance of lung scintigraphy in suspected pulmonary embolic disease

AIM

to determine the effectiveness of a new imaging algorithm in the investigation of suspected pulmonary embolism (PE).

MATERIALS AND METHODS

A new imaging algorithm for suspected PE was introduced following the installation of a multisection computed tomography (CT) machine at our institution. Before its installation, patients with suspected PE were evaluated with ventilation/perfusion (V/Q) scintigraphy. Subsequently, patients were triaged according to chest radiography (CR) and respiratory history to either lung scintigraphy or CT pulmonary angiography (CTPA). Patients with a normal CR and no history of lung disease were evaluated using perfusion (Q) scintigraphy [ventilation (V) scintigraphy was no longer performed]. Patients with an abnormal CR, asthma or chronic lung disease were evaluated using CTPA. All V/Q images in a continuous 3-year period before the introduction of the new imaging algorithm and all Q images performed in a 3-year period after its introduction were retrospectively reviewed. Imaging reports were categorized into normal, non-diagnostic (low or intermediate probability) or high probability for PE. Patients in the later group who subsequently underwent CTPA, were also reviewed.

RESULTS

After the policy change the percentage of normal scintigrams significantly increased (39 to 60%; p<0.001). There was a non-significant increase in the percentage of high probability scintigrams (15 to 18%; p=0.716). Overall the diagnostic yield of lung scintigraphy improved significantly (54 to 78%; p<0.001).

CONCLUSION

the diagnostic performance of lung scintigraphy can be improved by careful triage of patients to either Q scintigraphy or CTPA based on clinical history and CR findings. Q scintigraphy remains a valuable diagnostic test in the investigation of suspected PE in carefully selected patients.

New directions in the treatment of infected pleural effusion

The optimum management of patients with parapneumonic effusion and empyema remains uncertain. This article will review the evidence and current opinion on the pathophysiology of this disease, the role of fibrinolytic therapy, and the use of modern surgical techniques.

Diagnosis of suspected venous thromboembolic disease in pregnancy

Venous thromboembolic disease is a leading cause of maternal mortality during pregnancy. Early and accurate radiological diagnosis is essential as anticoagulation is not without risk and clinical diagnosis is unreliable. Although the disorder is potentially treatable, unnecessary treatment should be avoided. Most of the diagnostic imaging techniques involve ionizing radiation which exposes both the mother and fetus to finite radiation risks. There is a relative lack of evidence in the literature to guide clinicians and radiologists on the most appropriate method of assessing this group of patients. This article will review the role of imaging of suspected venous thromboembolic disease in pregnant patients, highlight contentious issues such as radiation risk, intravenous contrast use in pregnancy and discuss the published guidelines, as well as suggesting an appropriate imaging algorithm based on the available evidence.

The safety and feasibility of extracorporeal high-intensity focused ultrasound (HIFU) for the treatment of liver and kidney tumours in a Western population

High-intensity focused ultrasound (HIFU) provides a potential noninvasive alternative to conventional therapies. We report our preliminary experience from clinical trials designed to evaluate the safety and feasibility of a novel, extracorporeal HIFU device for the treatment of liver and kidney tumours in a Western population. The extracorporeal, ultrasound-guided Model-JC Tumor Therapy System (HAIFU Technology Company, China) has been used to treat 30 patients according to four trial protocols. Patients with hepatic or renal tumours underwent a single therapeutic HIFU session under general anaesthesia. Magnetic resonance imaging 12 days after treatment provided assessment of response. The patients were subdivided into those followed up with further imaging alone or those undergoing surgical resection of their tumours, which enabled both radiological and histological assessment. HIFU exposure resulted in discrete zones of ablation in 25 of 27 evaluable patients (93%). Ablation of liver tumours was achieved more consistently than for kidney tumours (100 vs 67%, assessed radiologically). The adverse event profile was favourable when compared to more invasive techniques. HIFU treatment of liver and kidney tumours in a Western population is both safe and feasible. These findings have significant implications for future noninvasive image-guided tumour ablation.

HRCT diagnosis of diffuse parenchymal lung disease: inter-observer variation

BACKGROUND

This study was designed to measure inter-observer variation between thoracic radiologists in the diagnosis of diffuse parenchymal lung disease (DPLD) using high resolution computed tomography (HRCT) and to identify areas of difficulty where expertise, in the form of national panels, would be of particular value.

METHODS

HRCT images of 131 patients with DPLD (from a tertiary referral hospital (n = 66) and regional teaching centres (n = 65)) were reviewed by 11 thoracic radiologists. Inter-observer variation for the first choice diagnosis was quantified using the unadjusted kappa coefficient of agreement. Observers stated differential diagnoses and assigned a percentage likelihood to each. A weighted kappa was calculated for the likelihood of each of the six most frequently diagnosed disease entities.

RESULTS

Observer agreement on the first choice diagnosis was moderate for the entire cohort (kappa = 0.48) and was higher for cases from regional centres (kappa = 0.60) than for cases from the tertiary referral centre (kappa = 0.34). 62% of cases from regional teaching centres were diagnosed with high confidence and good observer agreement (kappa = 0.77). Non-specific interstitial pneumonia (NSIP) was in the differential diagnosis in most disagreements (55%). Weighted kappa values quantifying the likelihood of specific diseases were moderate to good (mean 0.57, range 0.49-0.70).

CONCLUSION

There is good agreement between thoracic radiologists for the HRCT diagnosis of DPLD encountered in regional teaching centres. However, cases diagnosed with low confidence, particularly where NSIP is considered as a differential diagnosis, may benefit from the expertise of a reference panel.

High-intensity focused ultrasound for the treatment of liver tumours

High-intensity focused ultrasound (HIFU) has been investigated as a tool for the treatment of cancer for many decades, but is only now beginning to emerge as a potential alternative to conventional therapies. In recent years, clinical trials have evaluated the clinical efficacy of a number of devices worldwide. In Oxford, UK, we have been using the JC HIFU system (HAIFU Technology Company, Chongqing, PR China) in clinical trials since November 2002. This is the first report of its clinical use outside mainland China. The device is non-invasive, and employs an extracorporeal transducer operating at 0.8-1.6 MHz (aperture 12-15 cm, focal length 9-15 cm), operating clinically at Isp (free field) of 5-15 KWcm(-2). The aims of the trials are to evaluate the safety and performance of the device. Performance is being evaluated through two parallel protocols. One employs radiological assessment of response with the use of follow-up magnetic resonance imaging and microbubble-contrast ultrasound. In the other, histological assessment will be made following elective surgical resection of the HIFU treated tumours. Eleven patients with liver tumours have been treated with HIFU to date. Adverse events include transient pain and minor skin burns. Observed response from the various assessment modalities is discussed.

The pitfalls of lung cancer screening

Lung cancer screening has received extensive attention for a number of years. As yet the goal of such a screening programme, a reduction in lung cancer mortality proven by a large randomised controlled trial, has not been achieved. Instead we are left with a number of unanswered questions and practical problems. In addition to the basic requirements for an effective screening programme, this review will identify the main pitfalls in lung cancer screening, with particular reference to multislice computed tomography. The specific difficulties relating to the identification of unimportant disease, the failure to identify important disease successfully, the consequences of investigating and treating identified disease and the financial costs will all be discussed.

Trainee reporting of computed tomography examinations: do they make mistakes and does it matter?

AIM

To determine the accuracy of trainees reporting computed tomography (CT) examinations.

MATERIAL AND METHODS

Over a 6-month period a single consultant reviewed all the CT examinations reported by registrars in one radiology department. After recording a provisional registrar report each examination was jointly reviewed by the consultant and registrar. The consultant's opinion was regarded as the gold standard. Data collected included: the error rate, whether an error was significant, leading to a change in patient management, and whether the mistake was a false-negative or positive.

RESULTS

Three hundred and thirty-one patients were included in the study. There was an overall error rate of 21.5%. A significant error leading to a change in management was made in 10% of reports, and a significant error that did not lead to a change in management was made in 9.3%; 2.1% of reports had insignificant errors; and 69% of errors were false-negatives.

CONCLUSION

Registrars make a significant number of errors affecting patient management when reporting CT and ideally all examinations should be reviewed by a consultant.

Bronchoscopy and surgical staging procedures and their correlation with imaging

Bronchoscopy, computed tomography (CT) and surgical staging procedures are complimentary methods of investigating patients with lung cancer. CT has been shown to be of value prior to bronchoscopy in the investigation of haemoptysis and malignancy, with excellent correlation between the detection of disease within the large airways on CT and direct visualisation at bronchoscopy. The utility of CT has been further increased by the development of multislice scanners with the generation of volumetric data enabling multiplanar image acquisition. Additionally the advent of CT co-registered with positron emission tomography will play an important role in guiding the choice of surgical staging procedures The increasing use of multidisciplinary medical care requires radiologists to have a greater understanding of the abilities and limitations of both bronchoscopy and surgical staging procedures in evaluating disease demonstrated on imaging.

Steroids, radiotherapy, chemotherapy and stents for superior vena caval obstruction in carcinoma of the bronchus: a systematic review

OBJECTIVE

To conduct a systematic review to determine the relative effectiveness of treatments currently employed in the management of superior vena caval obstruction (SVCO).

SEARCH STRATEGY

Electronic searching of the Cochrane Clinical Trials Register, Medline and Embase with identification of further studies from references cited in trials identified by electronic searching.

SELECTION CRITERIA

Both randomized and non-randomized controlled trials in which patients with carcinoma of the bronchus and SVCO had been treated with any combination of steroids, chemotherapy, radiotherapy or insertion of an expandable metal stent.

DATA COLLECTION AND ANALYSIS

There were three randomized and 98 non-randomized studies of which two and 44 respectively met the inclusion criteria.

MAIN RESULTS

Superior vena caval obstruction was present at diagnosis in 10.0% of patients with small cell lung cancer (SCLC) and 1.7% of patients with non-small cell lung cancer (NSCLC). In one small randomized trial in SCLC, the rate of SVCO relapse was not significantly reduced by giving radiotherapy on completion of chemotherapy. In another, in NSCLC, the addition of induction chemotherapy to a course of synchronous chemo-radiotherapy did not provide greater relief of SVCO. In SCLC chemotherapy and/or radiotherapy relieved SVCO in 77%; 17% of those treated had a recurrence of SVCO. In NSCLC, 60% had relief of SVCO following chemotherapy and/or radiotherapy; 19% of those treated had a recurrence of SVCO. Insertion of an SVC stent relieved SVCO in 95%; 11% of those treated had further SVCO but recanalization was possible in the majority resulting in a long-term patency rate of 92%. Morbidity following stent insertion was greater if thrombolytics were administered.

REVIEWERS' CONCLUSIONS

Chemotherapy and radiotherapy are effective in relieving SVCO in a proportion of patients whilst stent insertion may provide relief in a higher proportion and more rapidly. The effectiveness of steroids and the optimal timing of stent insertion (whether at diagnosis or following failure of other modalities) remain uncertain.

Non-traumatic thoracic emergencies: imaging and treatment of thoracic fluid collections (including pneumothorax)

Cross-sectional imaging has revolutionised the radiological diagnosis of pleural collections. Not only can the precise location and volume of a pleural effusion be established, but also features specific for the aetiology of the effusion can be demonstrated. Increasingly, radiologists are called upon to perform image-guided biopsies, aspirations and small bore chest drain placement, all of which have been shown to be safe and efficacious. Pneumothoraces occurring due to acute trauma and in an intensive care setting can also benefit from radiological input, both in terms of diagnosis and image-guided treatment.