Search

PURPOSE: To determine the incidence and prognostic implications of non-enhancing cortical FLAIR (fluid attenuated inversion recovery) hyperintensity in histologically-proven glioblastomas. MATERIALS AND METHODS: Institutional Human Research Ethics Committee approval was obtained. Patients with a new diagnosis of glioblastoma between September 2007 and December 2010 were identified. Only patients with at least FLAIR and post-contrast T1-weighted sequences were included. Pre-operative Magnetic Resonance Imaging studies were reviewed together by two readers to determine whether there was evidence of non-enhancing cortical signal abnormality, based primarily on the FLAIR sequence. It was graded as either 'negative', 'minor' (a thin rim around enhancing tumour) or 'more extensive'. Patient survival was then compared between groups, correcting for age, sex, performance status, axial measurements of the largest enhancing lesion and location (deep, periventricular or peripheral). RESULT(S): 151 patients met the inclusion criteria. 77 patients (51%) had evidence of non-enhancing cortical signal abnormality - minor in 37 of these patients (median survival 220 days) and more extensive in 40 (median survival 310 days). The 74 patients without non-enhancing cortical signal abnormality had a median survival of 261 days. On multivariate analysis, there was no significant difference in survival between the three groups (p=0.109 comparing 'negative' and 'minor'; p=0.399 comparing 'negative' and 'more extensive'). The only significant differences in survival were when assessing only patients with peripherally-located enhancing lesions, when the presence of non-enhancing cortical signal abnormality was associated with worse survival (hazard ratio=3.4, p=0.003 for 'minor'; HR=2.3, p=0.038 for 'more extensive'). CONCLUSION(S): Non-enhancing cortical signal abnormality is common in glioblastoma, occurring in about half of cases. In general, its presence does not alter survival, and facto

PURPOSE: To determine the incidence and significance of multiple enhancing lesions in histologically-proven glioblastomas. MATERIALS AND METHODS: Institutional Human Research Ethics Committee approval was obtained. Patients with a new diagnosis of glioblastoma between September 2007 and December 2010 were identified. Pre-operative Magnetic Resonance Imaging (MRI) studies were reviewed to determine whether or not there was more than one enhancing lesion and, if present, whether there was evidence on imaging of a communication between lesions (multifocal) or not (multicentric). The presence of a communication was predominantly determined using the fluid attenuated inversion recovery (FLAIR) sequence. Patient survival was then compared between groups, correcting for age, sex, performance status, axial measurements of the largest enhancing lesion and location (deep, periventricular or peripheral). RESULT(S): 55 of 167 patients (33%) had more than one discrete enhancing lesion. In the majority (49 of 55, or 89%), there was evidence of a communication between all lesions, ie. a multifocal glioblastoma. The communication was parenchymal (along white and/or grey matter, including the corpus callosum) in 45 of these, subependymal in three cases and leptomeningeal in one case. There was no convincing imaging communication in six patients, consistent with a multicentric glioblastoma. Patients demonstrating multiple enhancing lesions had a median survival of 183 days, compared to 304 days for patients without multiple lesions. There was no difference in survival on multivariate analysis, however (p=0.747). A deep location was predictive of worse survival (p<0.001 compared to a peripheral location; p=0.008 compared to a periventricular location), and was more common in patients with multiple lesions (35 of 55, or 64%) compared to those without (38 of 112, or 34%). CONCLUSION(S): The presence of multiple enhancing lesions in glioblastoma is relatively common, occurring in about o

Purpose: The new Philips Allura Clarity upgrade allows Xray reduction during image acquisition by automatic motion compensation, temporal and spatial noise reduction and image enhancement. Our aim was to quantify the radiation dose reduction achieved after installation of the Philips Allura Clarity platform compared to the Philips Allura Xper platform. Method(s): Polymethylmethacrylate (PMMA) phantoms of 4 different thickness (15, 18, 20 and 23 cm) were used to simulate patient head attenuation. A direct dosimeter was used to measure Air Kerma rates (AKR) during fluoroscopy and cerebral digital subtraction angiography (DSA) on the Philips Allura Xper platform, and then again after the Philips Allura Clarity upgrade. The measurements conformed to the International Electrotechnical Commission (IEC) standards i.e. no table top, X-ray beam focus to PMMA entrance distance of 62.5 cm, source to image distance of 105 cm and dosimeter placement at the PMMA entrance. Result(s): The pre and post Philips Allura Clarity upgrade fluoroscopy AKRs for 15, 18, 20 and 23 cm phantoms were 0.09 to 0.08, 0.15 to 0.12, 0.20 to 0.19, 0.32 to 0.23 mGy/s respectively. Mean dose reduction was 17% (range 9-30%). In DSA the pre and post upgrade AKRs for 15, 18, 20 and 23 cm phantoms were 3.08 to 0.23, 6.04 to 0.58, 9.57 to 0.89, 14.68 to 1.74 mGy/frame respectively. Mean dose reduction was 90% (range 88-92%). Conclusion(s): This study confirms significant radiation dose reduction, particularly during DSA, after installation of the Philips AlluraClarity imaging platform.

PURPOSE: To determine the incidence of additional lesions consistent with low grade glioma in patients with a new diagnosis of glioblastoma, with subsequent imaging follow-up. MATERIALS AND METHODS: Institutional Human Research Ethics Committee approval was obtained. Patients with a new diagnosis of glioblastoma between September 2007 and December 2010 were identified. Only patients with at least FLAIR (fluid attenuated inversion recovery) and post-contrast sequences were included. Pre-operative Magnetic Resonance Imaging (MRI) studies were reviewed together by two readers to determine whether there were lesions with imaging appearances consisting with a low grade glioma separate from the dominant tumour (ie. multicentric lesions on imaging). This was based primarily on the FLAIR sequence, with the diagnosis being made on the presence of cortical signal hyperintensity and mass effect, without post-contrast enhancement. RESULT(S): 9 of 151 patients (6%) had lesions consistent on imaging with a low grade glioma separate from the dominant tumour. Their median survival was 183 days, compared to 264 days for patients without this feature. This worse survival was statistically significant on multivariate analysis (p=0.024). There was a high incidence of multiple enhancing lesions separate from the focus of low grade tumour, occurring in 5 of these 9 patients. Excluding studies performed immediately post-operatively, follow-up MRIs were performed in three patients. In all three, these additional areas of tumour developed enhancement and evidence of necrosis within one year, and became confluent on FLAIR with the dominant lesion. In a fourth patient, a further separate lesion had developed evidence of necrosis in the 22-day interval between the full diagnostic study and the limited postcontrast study performed for stereotaxis. CONCLUSION(S): The presence of a low grade glioma separate from the dominant lesion is an uncommon finding in glioblastoma, but likely to be useful i

Background: It has been described that lacunar infarct is characterized by its smallish size (15-20 mm) in the axial plane. However, the size of the basal ganglia artery responsible for this type of infarct is uncertain. Detection of small arterial occlusion is not possible with current angiography, hindering correlation of arterial occlusion with subcortical infarct size. Recently, investigators have published microangiographic templates of arteries supplying the basal ganglia. These templates display first-order (proximal) to third-order (distal) branching of these arteries and can help with estimating the likely site of arterial disease in subcortical infarcts. We correlated the dimensions of subcortical infarcts with the order of arterial branching described in a microangiographic template. Such data may provide further clues about the type of arteries associated with subcortical infarcts and assist in refining the concept of lacunar infarction. Method(s): Patients with subcortical infarcts on MR imaging (MRI) admitted to our institution between 2009 and 2011 were included in the study. Infarcts were manually segmented and registered to a standard brain template. These segmented infarcts were scaled and overlapped with published microangiographic templates, and used by 6 raters who independently estimated the branching order of arterial disease that might result in these infarcts. We used regression analysis to relate these ratings to infarct dimensions. Result(s): Among 777 patients, there were 33 (58% male) patients with subcortical infarcts. The mean age was 63.1 +/- 15.1 years. Infarct dimensions for the groups were as follows: group 1 (first-order branch): height 37.6 +/- 7.4 mm, horizontal width 21.2 +/- 11.6 mm, anterior-posterior length 36.8 +/- 20.1 mm; group 2 (second-order branch): height 25.2 +/- 7.9 mm, horizontal width 16.6 +/- 22.8 mm, anterior-posterior length 16.1 +/- 8.0 mm; group 3 (third-order branch): height 11.6 +/- 5.7 mm, axial width 5.3

Purpose: Current MRI guidelines from the Consortium of Multiple Sclerosis Centers recommend the use of both T2 and proton density (PD) weighted sequences in the assessment of multiple sclerosis (MS) spinal cord lesions. However, there is a paucity of literature comparing the utility of these two sequences for spinal cord lesion detection. We sought to compare cervical cord MS lesion detection and conspicuity on sagittal 1.5T PD and T2 weighted MRI. Methods and Materials: Nineteen patients with MS or clinically isolated syndromes were included in this retrospective analysis. All patients were examined with sagittal PD and T2 cervical cord imaging on a 1.5T Siemens Magnetom Avanto MRI scanner with a 4-channel neck matrix coil. Two neuroradiologists identified MS lesions, with consensus agreement for single viewer lesions. Regions of interest were obtained within lesions using the software program, Osirix v3.0.2. Quantitative analysis comparing the normalised lesion-to-cord contrast ratio (LCCR) and the signal-to-noise ratio (SNR) for each sequence was performed using the Wilcoxon rank-sum test, where P < 0.05 was considered statistically significant. Result(s): Fifteen patients were found to have cervical cord lesions - 20 lesions were identified on T2 and 34 lesions on PD weighted imaging. Twenty-two lesions seen on PD imaging were not seen on T2 imaging, and eight lesions seen on T2 imaging were not seen on PD imaging. PD and T2 weighted imaging were comparable for both the LCCR (PD 0.25 +/- 0.02 vs. T2 0.30 +/- 0.03, P = 0.24) and SNR (PD 50.87 +/- 3.80 vs. T2 50.82 +/- 4.50, P = 0.85). Conclusion(s): Although MS lesion conspicuity is similar with both T2 and PD weighted cervical cord MRI, several MS lesions detected on PD weighted imaging were not seen on T2 imaging. For cervical cord MS lesion detection, PD weighted imaging may be superior than T2 weighted imaging.

Background The ischemic penumbra defines the cerebral tissue which can be salvaged with prompt reperfusion. This is defined by thresholded volumes of perfusion defect based on magnetic resonance image (MRI) or computer tomography (CT) perfusion. This volume based approach excludes consideration of regional difference such as variation in vascular supply relating to the degree of leptomeningeal anastomoses. Hence a voxel based method may help to clarify tissue fate in different brain regions. We hypothesis that the likelihood of tissue infarction differs depend on the brain region. Method Ischemic stroke patients presented within 4.5 hours of onset, received tissue plasminogen activator (tpa) with middle cerebral artery (MCA) occlusion on CT angiography and had CT perfusion (64 multirow scan) were recruited. Ischemic penumbra was defined as region of perfusion defect (Tmax > 2 seconds) not overlapped by the infarct core (cerebral blood volume > 2.5 seconds). Final infarct was assessed by MRI beyond 3 months from onset. Positive likelihood ratio for infarction (PLR) was generated at a voxel level, taking into account the relationship between the finding of penumbra and infarct at a given voxel. We defined voxels with PLR between 5-10 as providing useful clinical information with regards to risk of infarction; and voxels PLR > 10 as highly likely to progress to infarction. Result 19 patients were studied with median age of 66 years (10 males). The regions within the penumbra supplied by the deep MCA compartment (striatocapsular and internal watershed regions) had PLR values > 10 while the more superficial compartment has PLR range of 1.3-5.0. The posterior temporoparietal region had PLR < 2. Conclusion The deep compartment of the MCA territory has very high PLR and is most likely to progress to infarction despite receiving tpa. A likelihood ratio approach may help to refine the zone least likely to infarct, the penumbra and the infarct core on CT perfusion imaging.

PURPOSE Double inversion recovery (DIR) has been shown to be more sensitive than T2 turbo spin echo (TSE) and FLAIR for detection of multiple sclerosis (MS) lesions in the brain. However DIR sensitivity in the cervical cord remains unexplored. The cervical cord to C6 is routinely included as part of brain DIR imaging. We hypothesised that detection of cervical cord lesions on brain DIR may mitigate the need for dedicated cervical cord T2/PD imaging. The aim of the study was to compare cervical cord MS lesion detection and conspicuity on sagittal 1.5 T DIR brain to PD TSE and T2 TSE cervical cord imaging. METHODS 40 patients being treated or investigated for MS over a six-month period with brain and cervical cord MRI were included in this retrospective analysis. Sagittal DIR, PD TSE and T2 TSE images were acquired on a 1.5 T Siemens Magnetom Avanto MRI scanner. A head and neck matrix coil combination was utilised for brain DIR, which included the cervical cord to C6. A 4-channel neck matrix coil was employed for PD TSE and T2 TSE sequences. Two neuroradiologists identified MS lesions, with consensus agreement for single viewer lesions. Regions of interest were obtained within lesions using Osirix v3.0.2. Quantitative analysis comparing the normalised lesion-to-cord contrast ratio (LCCR) and the signal-to-noise ratio (SNR) for each sequence was performed using sample T-tests, where P>0.05 was considered statistically significant. RESULTS 81 cervical cord lesions were detected in 19 patients - 25 on DIR, 25 on T2 TSE and 31 on PD TSE. Five patients with positive T2 TSE scans had negative DIR imaging. Compared to PD and T2, DIR had greater LCCR (DIR 1.51+/-0.09 vs. PD TSE 0.26+/-0.02, P<0.0001; DIR vs. T2 TSE 0.30+/-0.03, P<0.0001), and higher SNR (DIR 126.90+/-5.94 vs. PD TSE 52.63+/-4.00, P<0.0001; DIR vs. T2 TSE 53.02+/-4.99, P<0.0001). CONCLUSIONS DIR detected lesions demonstrate superior contrast resolution and SNR compared to T2 TSE and PD TSE imaging. However mul

Background: CT Coronary Angiography provides accurate noninvasive evaluation of coronary arteries but also images lung parenchyma and other mediastinal structures. Little is known about the range and incidence of non-cardiac findings in the Australian population and while CT screening has been shown to reduce mortality in high risk individuals the significance of identified pulmonary nodules in this mixed risk population is unknown. A lack of data regarding the malignant potential of these incidentally identified nodules makes evaluation of the relative risk/benefit of both initial imaging of the lung and subsequent surveillance scanning is difficult. Method(s): A retrospective analysis was performed on reports of all cardiac CT scans done in the calendar year 2012. Descriptive data was collected including baseline patient characteristics, type of nodule and smoking history, as well as whether a full field or restricted field view was performed. Surveillance radiological data and pathology was collected on a sub-group of the population. Result(s): 2500 Cardiac CT scans analysed with 48% females. Reports analysed for presence of lung nodules and type of nodule with most common nodule granuloma. Total lung nodules 14% (355) with follow up recommended by specialist radiologists; significant variation from recommendation in practice was noted. 39% of population positive for smoking exposure placing them in high risk population. No episodes of malignancy within follow up CT scans with the majority of nodules being stable over the follow up period. Majority of nodules were <4mm making up 60% of the total nodules described, 4-8mm 20% nodules of described nodules, >8mm making up 12% of nodules. Pulmonary Cysts represented 4% of nodules. Subpleural nodules described separately and making up a minority of nodules. Conclusion(s): Cardiac CTs are an increasingly common modality used to evaluate coronary artery disease. Pulmonary nodules are a common finding with a prevalence in

Background Therapeutic neurointerventional (NI) procedures have become a significant source of radiation exposure during the treatment of cerebrovascular disease. While there are well-established radiation dose reference levels (DRLs) for diagnostic imaging, no similar NI DRLs are available. We analyzed the patient radiation dose for therapeutic NI procedures at a tertiary teaching hospital, with an aim to develop local DRLs that could form the foundation for developing national NI radiation safety guidelines. Method Retrospective analysis of radiation dose area product (DAP) in Gy. Cm2 for consecutive patients undergoing therapeutic NI procedures between July 2011 and April 2014 was performed. NI procedures were categorized into arteriovenous malformation (AVM) embolization, cerebral aneurysm embolization (primarily coiling vs balloon/stent assisted) and cerebral vasospasm procedures. Median and inter-quartile radiation dose levels were calculated for each NI category. The 75th percentile was deemed to be the local DRL. Wilcoxon signed-rank test was performed for statistical correlation. Results A total of 303 NI procedures were included. Patients undergoing AVM embolization received a significantly higher radiation dose (n = 44; median 338 Gy. Cm2 [IQR 225-528 Gy. Cm2]) than patients undergoing cerebral aneurysm embolization (n = 188; median 211 Gy. Cm2 [IQR 130-328 Gy. Cm2]; p = 0.003). Patients treated with primary coiling received a significantly lower radiation dose (n = 96; median 170 Gy. Cm2 [IQR 125-282 Gy. Cm2]) than patients undergoing stent/balloon assisted aneurysm embolization (n = 92; median 241 Gy. Cm2 [IQR 145-369 Gy. Cm2]); p = 0.0002). Patients undergoing cerebral vasospasm procedures (n = 71) received median 161 Gy. Cm2 [IQR 106-219 Gy. Cm2] of radiation. Conclusion Therapeutic NI procedures are a significant source of radiation exposure, particularly for AVM embolization. Proposed NI radiation DRLs based on the 75th percentile for DAP were 528 G

A 40-year-old male patient had his right femoral vein catheterised following admission with altered conscious state from polypharmacy overdose. The procedure was documented as successful and uncomplicated. A postprocedural chest radiograph demonstrated a linear metallic opacity projecting over the superior vena cava and inferior vena cava (SVC and IVC, respectively), with superior and inferior ends not visualised. This did not alert the attending radiologist and intensivist who might have assumed such a metallic object to be external to the patient. Only the central line was removed prior to patient discharge 2 days later. The patient died 2 years later from unrelated streptococcal pneumonia complicated by septicaemia and multiorgan failure. The postmortem discovered a central venous guidewire in the IVC across the right atrium into SVC. Copyright 2014 BMJ Publishing Group. All rights reserved.

Summary Retroperitoneal sarcomas are a rare disease. The overall 5-year survival rate for these lesions remains low, and surgical management offers the only option for effective treatment and potential for cure. Radiotherapy is increasingly being employed in addition to standard surgical treatment. Improvements in cross-sectional imaging have also facilitated better characterisation of lesions, preoperative planning and long-term follow-up. This article reviews the current literature and documents the various types of retroperitoneal sarcomas with a particular approach to their imaging features. We also highlight the pathology, diagnostic methods and most current management of these tumours. © 2013 The Royal Australian and New Zealand College of Radiologists.

Background & Aim: Due to the small size of the arteries (third order branch occlusion and beyond) involved in lacunar stroke, documenting occlusion on angiogiography is rare in vivo. Recently, investigators have published microangiographic templates of arteries supplying the basal ganglia (lenticulostriate artery [LA] and recurrent artery of Heubner [RAH]). These templates display first (proximal) to third (distal) order branching of these arteries of the basal ganglia and can help with estimating the likely site of of arterial occlusion and dimensions of third order occlusion. Method(s): Cases were chosen from patients admitted to our institution from 2009 to 2011 with MRI. Scans were reviewed for the presence subcortical infarcts in the LA and RAH territories. These infarcts were manually segmented and linearly registered to a standard template using an affine transformation. These segmented infarcts were scaled and overlapped with published microangiographic templates. Five raters independently estimated the branching order of arterial oclusion using these templates. Result(s): in 777 patients, there were 33 (58% male) patients with subcortical infarcts. The mean age was 63.1 +/- 15.1 years. The regression model showed that infarct volume was associated with the branching order of these arteries (beta = -11.5 mm3 per change in branching order occlusion, 95% CI -18.9- -4.0). The regression model showed that infarct volume was associated with the branching order of the small penetrating artery (beta = -9.1 ml per change in branching order occlusion, 95% CI -15.3- -2.9, P < 0.01). For infarct height, the relationship with branching order of occlusion was beta = -14.6 mm per change in branching order occlusion, 95% CI -18.8- -10.3, P < 0.01). Third order branch occlusion was associated with height 8.7 +/- 4.1 mm, horizontal width 4.7 +/- 3.7 mm, anterior to posterior length 3.2 +/- 2.2 mm. Discussion(s): This study has provided a method for estimating of the type of

Purpose: To compare the extent and intensity of FLAIR CSF flow related artefacts with and without BLADE (motion correction with multiple radial blade acquisition). Methods and materials: Retrospective review of 22 patients who received FLAIR with and without BLADE. Patients were scanned on three different scanners, two of which are 1.5T, the remainder being 3T. The CSF spaces in the pre-pontine cistern were evaluated for presence of flow related artefact. The cases were blindly assessed by an experienced neuroradiologist (SS) and an MRI fellow (CF). Extent/ Intensity of artefact was assessed on a four point scale (ranked 0-3). Result(s): Flow related artefact was identified on 17 of 22 BLADE studies and 16 of 22 rectilinear FLAIR. The average score based on the four point scale was 1.67 for BLADE and 0.81 for rectilinear FLAIR. The effect was much more pronounced at 3T. Average scores for 3T BLADE was 2.13 compared to 1.00 on rectilinear FLAIR. At 1.5T average scores were 0.43 for BLADE and 0.29 for FLAIR. Conclusion(s): Despite being widely regarded as having less pulsation, ghosting and movement artefacts when compared to conventional FLAIR sequences; BLADE FLAIR images demonstrate increased CSF flow related artefact extent and intensity in the prepontine cistern. The FLAIR with BLADE appearances may mimic the appearance of subarachnoid haemorrhage whereas conventional FLAIR on modern MRI equipment is less likely to result in this appearance. This effect is more pronounced on 3T field strengths when compared to 1.5T. Awareness of this difference may assist in avoiding a false positive subarachnoid haemorrhage diagnosis when FLAIR has been acquired with the BLADE technique.

Purpose: The petromastoid canal is a normal structure which is particularly prominent in young children and for this reason can be misinterpreted as pathological. The purpose of this study was to establish the normal size and development of the petromastoid canal at various ages in young children. Method(s): A retrospective study of CT scans of the petrous temporal bone, performed between 2007 and 2011 at a tertiary centre, in children <7 years of age who were identified in a search of the Radiology Information System. Eighty patients were identified (age range: 4 months to 6 years 10 months, median age 3 years 2 months, 56% male). All studies were performed for assessment of hearing loss. The width, length and shape of the petromastoid canal were recorded and categorised by age. The shape of the petromastoid canal was divided into 4 subtypes: small curvilinear, small with a steep angle, large bulky with 'finger like' extensions, small and short ending in pneumatised subarcuate cells. Result(s): The petromastoid canal was uniformly large and usually readily visible in the first year of life. It reduces in size to be a relatively subtle finding by the age of 3 years. When the canal is prominent in the first year of life, the temporal bones generally show no pneumatised cells in the subarcuate region and less ossification of the otic capsule. Conclusion(s): The petromastoid canal is large in the newborn and progressively narrows in association with progressive pneumatisation of the temporal bone and ossification of the otic capsule. Understanding the normal variation, development and imaging appearances of this structure as detailed will reduce the risk of imaging misinterpretation.

Purpose: To compare the conspicuity of subarachnoid blood on CT with MRI FLAIR and susceptibility weighted imaging (SWI) sequences in the setting of acute subarachnoid haemorrahge. Methods and materials: Retrospective, blinded review of 20 patients presenting with aneurysmal subarachnoid haemorrhage has been performed by two experienced neuroradiologists (WC and MH). Patients who presented with aneurysmal subarachnoid haemorrhage and underwent CT and MRI prior to undergoing craniotomy were included. Each modality/sequence was evaluated independently at two week intervals. The subarachnoid space was divided into 7 sections: interhemispheric, frontoparietal, occipitotemporal, sylvian fissure, perimesencephalic, posterior fossa, intra-ventricular. Result(s): When the subarachnoid space was considered in its seven sections blood was detected in 358 instances on either CT, SWI or FLAIR - 97 for CT, 115 for FLAIR and 146 for SWI. Haemorrhage was seen on all three on 57 occasions. It was detected on only one on 73 occasions - 18 for CT, 19 for FLAIR and 36 for SWI. Blood was detected only on MRI on 88 occasions - 19 FLAIR exclusively, 36 SWI exclusively, 33 both FLAIR and SWI. In addition there were 6 instances where blood was identified on CT and FLAIR only and 19 instances of blood on CT and SWI only. Overall blood was detected the most on SWI, followed by FLAIR and then CT. When considering individual patients blood was identified in all modalities in 17 cases. Of the remaining patients one had blood only on CT, one only on FLAIR and one on both CT and SWI. In the interhemispheric region, cerebral convexity sulci and intraventricular locations SWI and FLAIR appeared to outperform CT. Conclusion(s): There are instances where aneurysmal subarachnoid haemorrage may be detected on MRI, but not CT. This was seen more frequently with SWI than FLAIR. SWI and FLAIR appear more sensitive in the interhemispheric region, cerebral convexity sulci and intraventricular locations. Thi

Objectives: 320-slice computed tomography (CT) provides 3-dimensional and dynamic imaging, resulting in the ability to assess motion analysis between two adjacent structures (the 4th dimension). Differential movements between two adjacent structures would indicate there is no fixation between the two structures. Method(s): Eight patients with non-small-cell lung cancers located adjacent to vital structures (e.g. the great vessels, n=4) or chest wall (n=4) where conventional CT was unable to exclude local invasion, underwent dynamic 4-dimensional CT assessment. In four patients, the lung tumour was abutting the chest wall. The remaining patients included a patient with a large 14 cm left lower lobe cancer abutting the descending thoracic aorta who had previous pleurodesis; a patient with an apical right upper lobe 6 cm cancer with static imaging appearances suggestive of tumour invasion into the apex and mediastinal surface (superior vena cava) of the thorax; a patient with a 3.5 cm cancer which had a broad 2.5 cm base abutting the distal aortic arch; and a patient with a 14 cm left upper lobe cancer abutting the aortic arch, descending thoracic aorta and chest wall. Differential movements between the tumour and adjacent structure on 4-D CT was considered indicative of the absence of frank invasion. Result(s): Dynamic 4-D imaging revealed differential movements between the tumour and the adjacent structures in all cases suggesting the absence of overt malignant invasion. Intraoperative assessment confirmed resectability of the cancers in all eight patients. Conclusion(s): Dynamic 4-dimensional 320-slice CT is useful in the preoperative assessment of lung cancer direct invasion into adjacent structures and hence resectability.

CT perfusion (CTP) has an important role in the acute management of stroke by confirming the diagnosis and providing quantification of infarct core and salvageable penumbra. The main limitation has been a limited scan volume. The newer multidetector 320 slice (MD320) scanners have a scan volume of 16 cm with the ability to cover the whole brain. It also has the ability to provide a dynamic CT angiogram (CTA) of the brain in the same acquisition. The aim of the study was to compare 4 cm vs 16 cm z-axis in the assessment of CTP. Retrospective non-randomised review of CTP carried out on MD320 scanner between 09/2008 and 01/2009 was undertaken. Two experienced readers reviewed the studies along with the 4 and 16 cm Z-axis CTP image data set. The outcome parameters assessed were extent of the original finding, additional findings and change to diagnosis. A total of 27 patients were reviewed, 14 patients were found to have abnormal CTP (mean age 58.1 years, 9 males and 5 females). The 16 cm z-axis increased the accuracy of infarct core in 78% and ischaemic penumbra quantification in 100% of the cases. It also diagnosed additional infarcts in the same vascular territory in 28% of cases and in a different vascular territory in 14%. The increased field of view with MD320 better defines the true extent of the infarct core and ischaemic penumbra. It also identified other areas of infarction that were not identified on the 4 cm Z-axis.

Purpose: CT brain is an important part of the investigation of first seizures. The use of intravenous contrast may be of benefit particularly in diagnosing brain tumours, abscess and vascular malformation. This increases the patient radiation exposure by two-fold and there is currently no supportive literature for this practice. We aim to assess the role of intravenous contrast in increasing the sensitivity in the initial diagnosis and workup of seizure disorders. Methods and materials: 144 patient files and images over a 12-month period (March 2009-March 2010) were retrospectively reviewed using the centre's PACS Database. Pre-contrast studies were initially assessed and the findings were documented. At the same setting, the post contrast CT brain images on the same patients were reviewed and any additional findings documented. The results were then analysed for statistical significance, in particular the additional diagnostic benefit of intravenous contrast. Result(s): In the pre-contrast group 50 patients had a CT abnormality in the brain. The addition of intravenous contrast demonstrated a new abnormality in only 1 further patient but this was not deemed a likely cause of seizure (venous angioma). In those patients where the addition of a contrast study was not deemed necessary by virtue of noncontrast imaging findings there was no additional diagnostic benefit Conclusion(s): The use of intravenous contrast does not appear to increase the diagnostic sensitivity of non-contrast CT brain in the initial workup of seizure disorders. Our study suggests that the current use of non-contrast CT brain is adequate for the assessment of these patients.

This study aimed to define cortical laminar necrosis and pseudolaminar necrosis and the macroscopic, microscopic and radiological appearances. Cortical laminar necrosis is a particular sub-type of cerebral infarction where there is selective necrosis of a lamina (layer) or a few laminae of the cerebral cortex (layers 3, 5 and 6 in decreasing frequency), because of 'selective vulnerability'. Biopsy proven cases have shown that there is often no haemorrhage or calcification in the cortex to account for the pre contrast T1 hyperintensity. Proposed causes of this signal change include fat laden macrophages, mineralisation and denatured proteins and cellular components. Cortical laminar necrosis and pseudolaminar necrosis are used interchangeably in the published work on radiology. The term pseudolaminar necrosis appears to have arisen as the necrosis may not be strictly laminar. A wide range of aetiologies have been described. Gyriform cortical hyperintensity on pre contrast T1 weighted images and gyriform enhancement are the hallmarks of cortical laminar necrosis. These signal characteristics will most frequently appear in the subacute phase approximately 2 weeks post event, being most prominent at 1-3 months. T2, fluid attenuated inversion recovery (FLAIR) and susceptibility-weighted imaging (SWI) signal intensity is variable. While gyriform cortical hyperdensity and enhancement on computed tomography (CT) have been associated with cortical laminar necrosis they are not specific and have not been proven histologically. Cortical laminar necrosis and pseudolaminar necrosis are used interchangeably in the published work on radiology. Both terms appear acceptable and the terms are synonymous for describing cortical necrosis with a dominant laminar distribution. The cortical precontrast T1 hyperintensity is characteristic and should allow a confident diagnosis.

This study aimed to provide a pictorial illustration of time resolved (4D) CTA appearances as carried out with 320 slice CT with whole brain coverage in a range of intracranial pathologies. All brain CT examinations carried out on a recently installed 320 slice CT were reviewed. Cases where time-resolved (4D) CTA was carried out were extracted and a subselection used to illustrate the variety of time-resolved (4D) CTA appearances across a range of intracerebral pathologies. Whole brain time-resolved (4D) CTA technique and normal appearances are illustrated and discussed. A range of neurovascular and non-neurovascular pathologies are showed. Whole brain 320 slice time-resolved (4D) CTA shows significant potential, particularly in neurovascular pathologies where it may, with further study, replace current more invasive investigations. This exhibit reflects our initial experience with this technique.

This study aimed to provide a pictorial illustration of the CT perfusion appearances as carried out with 320 slice CT with whole brain coverage in a range of intracranial pathologies. All brain CT examinations carried out on a recently installed 320-slice CT were reviewed. Cases where CT perfusion was carried out were extracted, and a subselection used to illustrate the variety of CT perfusion appearances across a range of intracerebral pathologies. Whole brain CT perfusion technique, normal appearances and parametric maps are illustrated and discussed. A range of neurovascular and non-neurovascular pathologies are showed. Whole-brain 320-slice CT perfusion shows significant potential in particularly neurovascular pathologies where it may, with further study, replace current invasive investigations. This exhibit refects our initial experience with this technique.

Introduction: Magnetic resonance imaging (MRI) is increasingly used to examine joints for research purposes. It may detect both suspected and unsuspected abnormalities. This raises both clinical and ethical issues, especially when incidental abnormalities are detected. The prevalence of incidental, potentially clinically significant abnormalities identified by MRI and their clinical significance in a population undergoing knee MRI in research studies are unknown. Method(s): We examined the prevalence of such lesions in healthy asymptomatic adults and those with symptomatic knee osteoarthritis (OA) undergoing knee MRI with limited sequences for the purpose of research. The MRI findings in 601 asymptomatic subjects and 132 with knee OA who underwent at least one limited knee MRI scan for cartilage volume measurement were examined by an MRI radiologist for the presence of potentially clinically significant abnormalities. Result(s): These were present in 2.3% of healthy and 2.3% of OA subjects. All required further investigation to exclude non-benign disease, including four with bone marrow expansion (0.7%), requiring further investigation and management. A single potentially life-threatening lesion, a myeloma lesion, was identified in a subject with symptomatic knee OA on their second MRI scan in a longitudinal study. Conclusion(s): As musculoskeletal MRI is increasingly used clinically and for research purposes, the potential for detecting unsuspected abnormalities that require further investigation should be recognized. Incorporating a system to detect these, to characterize unexpected findings, and to facilitate appropriate medical follow-up when designing studies using this technology should be considered ethical research practice. © 2008 Grainger et al.; licensee BioMed Central Ltd.

INTRODUCTION: Magnetic resonance imaging (MRI) is increasingly used to examine joints for research purposes. It may detect both suspected and unsuspected abnormalities. This raises both clinical and ethical issues, especially when incidental abnormalities are detected. The prevalence of incidental, potentially clinically significant abnormalities identified by MRI and their clinical significance in a population undergoing knee MRI in research studies are unknown. METHODS: We examined the prevalence of such lesions in healthy asymptomatic adults and those with symptomatic knee osteoarthritis (OA) undergoing knee MRI with limited sequences for the purpose of research. The MRI findings in 601 asymptomatic subjects and 132 with knee OA who underwent at least one limited knee MRI scan for cartilage volume measurement were examined by an MRI radiologist for the presence of potentially clinically significant abnormalities. RESULTS: These were present in 2.3% of healthy and 2.3% of OA subjects. All required further investigation to exclude non-benign disease, including four with bone marrow expansion (0.7%), requiring further investigation and management. A single potentially life-threatening lesion, a myeloma lesion, was identified in a subject with symptomatic knee OA on their second MRI scan in a longitudinal study. CONCLUSION: As musculoskeletal MRI is increasingly used clinically and for research purposes, the potential for detecting unsuspected abnormalities that require further investigation should be recognized. Incorporating a system to detect these, to characterize unexpected findings, and to facilitate appropriate medical follow-up when designing studies using this technology should be considered ethical research practice.