Andrew Scarsbrook

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) (nu2009=u200994), CTPA (nu2009=u20099) or both (nu2009=u20092), 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

PET/CT in primary musculoskeletal tumours: a step forward.

Hybrid imaging with combined positron emission tomography/computed tomography (PET/CT) plays an important role in the staging and management of a wide variety of solid tumours. However, its use in the evaluation of musculoskeletal malignancy has not yet entered routine clinical practice. Cross-sectional imaging with magnetic resonance imaging (MR) and computed tomography have well-established roles but there is increasing evidence for the selective use of PET/CT in the management of these patients. The aims of this article are to review the current evidence and clinical applications of PET/CT in primary musculoskeletal tumours and discuss potential future developments using novel PET tracers and integrated PET/MR.

Clinical impact of FDG PET-CT on management decisions for patients with primary biliary tumours

ObjectivesTo assess the impact on clinical management of introducing 18F-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET)-computed tomography (CT) in to the work-up of patients with primary and recurrent biliary malignancy.MethodsConsecutive patients with primary biliary tumours undergoing FDG PET-CT at a single large tertiary referral centre between November 2007 and September 2010 were retrospectively analysed. Findings on FDG PET-CT compared with CT/magnetic resonance imaging (MRI) and impact on subsequent patient management were evaluated. Impact was divided into: (1) major—detection of occult disease or characterisation of indeterminate lesion(s) on CT/MRI; (2) minor—confirmation of suspected metastases seen on CT/MRI; (3) no impact.ResultsOne hundred and eleven patients underwent 118 FDG PET-CT scans, including 30 with suspected gallbladder carcinoma and 81 with cholangiocarcinoma. Eighty-nine scans were performed for initial staging, five for restaging following neoadjuvant chemotherapy and 24 for suspected disease recurrence. In 33 cases (28xa0%), FDG PET-CT had a major impact on subsequent patient management (39xa0% gallbladder carcinoma, 26xa0% intrahepatic cholangiocarcinoma and 21xa0% extrahepatic cholangiocarcinoma). FDG PET-CT had a minor impact in 20 cases (17xa0%) and no impact in 65 cases (55xa0%).ConclusionsBy detecting occult metastatic disease and characterising indeterminate lesions, FDG PET-CT can have a major influence on clinical decision-making in primary and recurrent biliary malignancy.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) masquerading as metastatic carcinoma with multiple pulmonary deposits

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is a rare pulmonary disorder presenting with multiple pulmonary nodules in association with a typical mosaic perfusion pattern on computed tomography. In this case, the absence of mosaic perfusion led to an erroneous initial diagnosis of pulmonary metastases from an unknown primary malignancy. This illustrates the importance of considering differential diagnoses when presented with imaging findings compatible with pulmonary metastases from an unknown primary, and highlights the importance of histopathologic confirmation in such cases.

The use of deformable image registration to integrate diagnostic MRI into the radiotherapy planning pathway for head and neck cancer

BACKGROUND AND PURPOSEnTo assess the accuracy of gross tumour volume (GTV) delineation for head and neck squamous cell carcinoma (HNSCC) using a diagnostic position MRI (MRI-D) deformably registered to the planning CT (pCT), by comparison with a dedicated planning position MRI (MRI-RT).nnnMATERIAL AND METHODSnFourteen patients with HNSCC underwent a T1-weighted MRI-D and MRI-RT. A reference GTV was defined as that delineated on MRI-RT rigidly registered to pCT. GTVs were delineated on: MRI-D and then registered to pCT by deformable image registration over the whole image (DIR-whole); MRI-D and then registered to pCT with rigid registration over a region of interest defined as GTV+3cm (Rigid-ROI); and on the pCT alone. These were compared using positional metrics to the reference.nnnRESULTSnGTVs delineated on MRI-D followed by DIR-whole were significantly more accurate than those delineated on CT alone. The mean Dice Similarity Coefficient was 0.6 and 0.72 for pCT and DIR-whole respectively. Use of MRI-D with Rigid-ROI provided no advantage over CT-only delineation.nnnCONCLUSIONSnContouring on MRI-RT rigidly registered to pCT should be considered as the gold standard for HNSCC. In radiotherapy centres lacking a dedicated MRI-RT, the use of an MRI-D with DIR-whole offers a significant advantage for the accuracy of GTV delineation over contouring on pCT alone.

Clinical impact of FDG PET-CT on the management of patients with locally advanced cervical carcinoma.

AIMnTo evaluate the impact of staging FDG PET-CT on the initial management of patients with locally advanced cervical carcinoma (LACC) and any prognostic variables predicting survival.nnnMATERIALS AND METHODSnRetrospective analysis of consecutive patients undergoing FDG PET-CT for staging of LACC in a single tertiary referral centre, between April 2008 and August 2011. Comparison was made between MRI and PET-CT findings and any subsequent impact on treatment intent or radiotherapy planning was evaluated.nnnRESULTSnSixty-three patients underwent FDG PET-CT for initial staging of LACC. Major impact on management was found in 20 patients (32%), a minor impact in five (8%), and no impact in 38 (60%). In those patients where PET-CT had a major impact, 12 had more extensive local nodal involvement, five had occult metastatic disease, two had synchronous tumours, and one patient had equivocal lymph nodes on MRI characterized as negative. PET-positive nodal status at diagnosis was found to be a statistically significant predictor of relapse-free survival (pxa0<xa00.05).nnnCONCLUSIONnStaging FDG PET-CT has a major impact on the initial management of approximately one-third of patients with LACC by altering treatment intent and/or radiotherapy planning. PET-defined nodal status is a poor prognostic indicator.

Pulmonary embolism in pregnancy

1778 www.thelancet.com May 22, 2010 a unique means of collecting relevant maternal mortality data), the main contributor to maternal mortality is indirect causes in the UK, hypertensive disorders in the Netherlands, and haemorrhage in France. Although thromboembolism con stitutes an important issue in pregnancy, it is important to keep in mind the actual pattern of causes of maternal mortality, in order to prioritise prevention strategies.

Evaluation of clinical target volume expansion required for involved site neck radiotherapy for lymphoma to account for the absence of a pre-chemotherapy PET-CT in the radiotherapy treatment position

BACKGROUND AND PURPOSEnInvolved site radiotherapy clinical target volume (CTV) for lymphoma requires an expansion to account for the absence of radiotherapy treatment-position pre-chemotherapy imaging, which is not widely implemented. This prospective imaging study aims to quantify CTV expansion required for neck radiotherapy.nnnMATERIALS AND METHODSn10 patients from a prospective single centre imaging study underwent a pre-chemotherapy FDG-PET-CT in both the diagnostic and radiotherapy treatment position, and subsequently received neck radiotherapy post-chemotherapy. CTVINRT and CTVdiagPET were delineated on the planning CT, following co-registration of the radiotherapy position PET-CT and side-by-side assessment of diagnostic PET-CT respectively.nnnRESULTSnIntra-observer variability was limited, with delineation of CTVINRT highly reproducible and slightly lower for CTVdiagPET (mean DICE 0.88 and 0.8 respectively). Superiorly, CTVdiagPET varied by -10 to +15mm from CTVINRT. Inferiorly, CTVdiagPET varied by -18 to +6mm from CTVINRT. Comparing CTVINRT and CTVdiagPET in the axial plane, the mean DICE was 0.74. Mean sensitivity index was 0.75 (range 0.59-0.91), showing that on average 75% of the CTVINRT was encompassed by the CTVdiagPET.nnnCONCLUSIONSnIn the absence of treatment-position PET-CT, CTV expansion cranially and caudally by 10mm and 18mm respectively, along with generous contouring in the axial plane, was required to encompass pre-chemotherapy disease.

Incidental thyroid nodule.

Thyroid nodules may be coincidentally detected as a result of neck imaging, and most are benign; the authors discuss how best to decide which nodules are most likely to be malignant and require further evaluation

Comparative effectiveness of 18F-FDG PET-CT and contrast-enhanced CT in the diagnosis of suspected large-vessel vasculitis

OBJECTIVEnLarge-vessel vasculitis (LVV) is a serious illness with potentially life-threatening consequences.xa0(18Fluorine) fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) has emerged as a valuable diagnostic tool in suspected LVV, combining the strengths of functional and structural imaging. This study aimed to compare the accuracy of FDG PET-CT and contrast-enhanced CT (CECT) in the evaluation of patients with LVV.nnnMETHODSnA retrospective database review for LVV patients undergoing CECT and PET-CT between 2011 to 2016 yielded demographics, scan interval and vasculitis type. Qualitative and quantitative PET-CT analyses included aorta:liver FDG uptake, bespoke FDG uptake distribution scores and vascular maximum standardised uptake values (SUVmax). Quantitative CECT data were assessedxa0for wall thickness and mural-lumen ratio. Receiver operating characteristics (ROC) curves were constructed to evaluate comparative diagnostic accuracy and a correlational analysis was conducted between SUVmax and wallxa0thickness.nnnRESULTSn36 adults (17 LVV, 19 controls) with a mean age (range) 63 (38-89) years, of which 17 (47%) were males were included. Time interval between CT and PET was mean [standard deviation (SD)] 1.9 (1.2) months. Both SUVmax and wallxa0thickness demonstrated a significant difference between LVV and controls, with a mean difference [95%confidence interval (CI)] for SUVmax 1.6 (1.1, 2.0) and wall thickness 1.25 (0.68, 1.83) mm, respectively. These two parameters were significantly correlated (p < 0.0001, R = 0.62). The area under the curve (AUC) (95%u2009CI) for SUVmax was 0.95 (0.88-1.00), and for mural thickening was 0.83 (0.66-0.99).nnnCONCLUSIONnFDG PET-CT demonstrated excellent accuracy whilst CECT mural thickening showed good accuracy in the diagnosis of LVV. Both parameters showed a highly significant correlation. In hospitals without access to FDG PET-CT or in patients unsuitable for PET-CT (e.g. uncontrolled diabetes) CECT offers a viable alternative for the assessment ofxa0LVV. Advances in knowledge: FDG PET-CT is a highly accurate test for the diagnosis of LVV. Aorta:liver SUVmax ratio is the most specific parameter for LVV. In hospitals without PET-CT or in unsuitable patients e.g. diabetics, CECT is a viable alternative.