Introduction of a Team Based Approach to Radiation Dose Reduction in the Enhancement of the Overall Radiation Safety Profile of FEVAR.

OBJECTIVES: Fenestrated endovascular aneurysm repair (FEVAR) exposes operators and patients to considerable amounts of radiation. Introduction of fusion of three-dimensional (3D) computed tomography (CT) with intraoperative fluoroscopy puts new focus on advanced imaging techniques in the operating environment and has been found to reduce radiation and facilitate faster repair. The aim of this study is to evaluate the radiation dose effect of introducing a team-based approach to complex aortic repair. METHODS: Procedural details for a cohort of 21 patients undergoing FEVAR after fusion-guided (Modern Group) imaging was introduced are compared with 21 patients treated in the immediate 12 months prior to implementation (Historic Group) at a centre with expertise in FEVAR. Non-parametric tests were used to compare procedure time (PT), air kerma, dose-area product (DAP), fluoroscopy time (FT), estimated blood loss (EBL) and pre- and post-operative estimated glomerular filtration rate (eGFR) between the groups. RESULTS: Change in operative approach resulted in a significant reduction in PT for the Modern group (median 285 mins; interquartile range 268-322) compared with the Historic group (450 mins; IQR 360-540 p = <0.001). There were reductions in skin dose for the Modern group (1.6 Gy; IQR 1.09-2.1) compared with the Historic group (4.4 Gy; 3.2-7.05 p = <0.001), and DAP (Modern 159 Gy.cm2; IQR 123-226 vs 264.93 Gy.cm2; 173.3-366.8 for Historic (p = 0.006). There were no significant differences in FT, and pre- and post-operative eGFR between the two groups. Weight and height were distributed equally across both groups. Structured dose reports including the changes in frame rate were not available for analysis. CONCLUSIONS: Implementation of a team-based approach to radiation reduction significantly reduces radiation dose. These findings suggest that the radiation safety awareness that accompanies the introduction of fusion imaging may improve the overall radiation safety profile of FEVAR for patients and providers.

A Comparison of Accuracy of Image- versus Hardware-based Tracking Technologies in 3D Fusion in Aortic Endografting.

OBJECTIVES: Fusion of three-dimensional (3D) computed tomography and intraoperative two-dimensional imaging in endovascular surgery relies on manual rigid co-registration of bony landmarks and tracking of hardware to provide a 3D overlay (hardware-based tracking, HWT). An alternative technique (image-based tracking, IMT) uses image recognition to register and place the fusion mask. We present preliminary experience with an agnostic fusion technology that uses IMT, with the aim of comparing the accuracy of overlay for this technology with HWT. METHOD: Data were collected prospectively for 12 patients. All devices were deployed using both IMT and HWT fusion assistance concurrently. Postoperative analysis of both systems was performed by three blinded expert observers, from selected time-points during the procedures, using the displacement of fusion rings, the overlay of vascular markings and the true ostia of renal arteries. The Mean overlay error and the deviation from mean error was derived using image analysis software. Comparison of the mean overlay error was made between IMT and HWT. The validity of the point-picking technique was assessed. RESULTS: IMT was successful in all of the first 12 cases, whereas technical learning curve challenges thwarted HWT in four cases. When independent operators assessed the degree of accuracy of the overlay, the median error for IMT was 3.9 mm (IQR 2.89-6.24, max 9.5) versus 8.64 mm (IQR 6.1-16.8, max 24.5) for HWT (p = .001). Variance per observer was 0.69 mm(2) and 95% limit of agreement ±1.63. CONCLUSION: In this preliminary study, the error of magnitude of displacement from the "true anatomy" during image overlay in IMT was less than for HWT. This confirms that ongoing manual re-registration, as recommended by the manufacturer, should be performed for HWT systems to maintain accuracy. The error in position of the fusion markers for IMT was consistent, thus may be considered predictable.

Editor's Choice - Effect of Branch Stent Choice on Branch-related Outcomes in Complex Aortic Repair.

OBJECTIVES: The use of branched stent grafts for the treatment of thoracoabdominal aneurysms [TAAA] is increasing, but mating stent graft choice has not been studied. This study combined experience of five high volume centres to assess a preferred mating stent. METHODS: Data from five centres were retrospectively combined. Patients were included if they underwent stent graft for treatment of TAAA that used only branches to mate with visceral and renal vessels. All patients with fenestrations in their device were excluded. Perioperative details, reintervention, occlusion, and death were recorded. Outcome of occlusion or reintervention, as well as a composite outcome of any death, occlusion, or reintervention was planned using a per-patient, and per-branch analysis. RESULTS: In 235 included patients, there were 940 vessels available for placement of mating stent. The average age of included patients was 70 years (SD 7.9), and 179 of the 235 were male. Medical comorbidities included diabetes in 29/234 (12.4%), current smoker in 81/233 (34.8%), and COPD in 77/234 (32.9%). The primary stent deployed was self-expanding in 556 branches, balloon expandable in 231 branches, and was unknown in 92 branches. After a mean of 20.7 months (SD 25) follow-up, there have been 44 incidents of occlusion or reintervention, of which 40 culprit stents are known. Where the stent placed is known, the event rate in renal branches (35/437, 8%) is higher than that of visceral branches (8/443, 1.8%). There is no difference in occlusion or reintervention between self-expanding and balloon expandable stents (HR 0.95, p = .91) but there is a statistically significant difference between renal and visceral artery occlusions (HR 3.51, p = 0.001). CONCLUSION: There appears to be no difference in occlusion or reintervention rate for branch vessels mated with balloon expandable compared with self-expanding stents. Renal events appear to outnumber visceral events in this population.

Mid-term Outcomes of Renal Branches Versus Renal Fenestrations for Thoraco-abdominal Aneurysm Repair.

OBJECTIVE/BACKGROUND: The objective was to investigate renal outcomes following endovascular repair of thoraco-abdominal aortic aneurysms (TAAA) comparing fenestrations with branches for the renal arteries. METHODS: Renal outcomes following TAAA endovascular repair performed with renal branches were collected from five high volume European centers and compared with renal outcomes following TAAA endovascular repair performed with renal fenestrations at one center. Renal re-intervention and occlusion rates, and freedom from any renal outcome and death were analyzed by patient and target vessel. Estimated glomerular filtration rate (eGFR) was calculated and collected pre-operatively and at the last available follow up. RESULTS: In total, 449 patients were included in this retrospective study (235 treated with branched devices [BEVAR] and 214 with fenestrated devices [FEVAR]). Altogether, 856 renal vessels were analyzed (445 perfused by branches and 411 by fenestrations). Both groups were comparable except for sex and smoking habits. Technical success rates were 95% and 99%, respectively. Mean ± SD follow up was 19 ± 18 months after BEVAR and 24 ± 20 months after FEVAR. During follow up, renal re-intervention rates were similar in both groups (4.7% vs. 5.2%). The renal occlusion rate was significantly higher following BEVAR (9.6% vs. 2.3%; p < .01), and the 2 year freedom for renal occlusion rate was 90.4% (SE 85.8-95.3%) following BEVAR and 97.1% (SE 94.6-99.7%) following FEVAR (p < .01). During follow up, a 12% median decrease in eGFR was observed following BEVAR versus 9% following FEVAR (non-significant). The 2 year survival rates were 73.4% (SE 66.6-80.9%) and 81.8% (SE 76.1-87.9%) following BEVAR and FEVAR, respectively. CONCLUSION: Mid-term renal outcomes following endovascular repair of TAAA are satisfactory. Endograft designs incorporating renal fenestrations rather than renal branches are associated with significantly lower occlusion rates. A prospective trial is now required to confirm these results.

Editor's choice - A shaggy aorta is associated with mesenteric embolisation in patients undergoing fenestrated endografts to treat paravisceral aortic aneurysms.

OBJECTIVES: Bowel ischaemia is a life-threatening complication of endovascular aneurysm repair. This study aims to evaluate the factors associated with mesenteric ischaemia in patients undergoing fenestrated aortic endografts to treat paravisceral aneurysms. METHODS: Consecutive patients undergoing double or triple fenestrated stent graft insertion were retrospectively analysed. No patients were declined surgery based on anatomic complexity. Preoperative demographics, procedure-related variables, and anatomical factors were examined. Using 3D software, the aortic thrombus volume from the coeliac axis to the lowest renal, aortoiliac tortuosity, and aortic irregularity index (as graded by 3 independent assessors, graded 0-3 based on severity) were compared. Univariate analysis was performed to identify risk factors for the development of bowel ischaemia. RESULTS: Ninety-nine patients underwent elective aneurysm repair (64 triple fenestrations and 35 double fenestrations), 5% of which developed bowel ischaemia, and of these 80% (4/5) died. Mesenteric ischaemia was significantly associated with increased aortic irregularity (median [range], 2 [1-3] vs. 1 [0-2], p = .005, ischaemia vs. no ischaemia) and increased thrombus volume (37 ± 8 vs. 21 ± 12, p = .007) but not aortoiliac tortuosity (1.4 [1.2-1.5] vs. 1.30 [1.2-1.7], p = .3), inferior mesenteric or internal iliac artery patency. Mesenteric ischaemia was also associated with a significantly higher preoperative creatinine (mean ± SD: 183 ± 74 vs. 111 ± 43, p = .007). CONCLUSIONS: The presence of aortic irregularity and increased thrombus volume in the paravisceral segment predicts the occurrence of mesenteric and renal ischaemia in patients treated with fenestrated endografts. This is likely to be related to graft manipulation and catheterisation of visceral vessels.

External iliac vein aneurysm: a case report and review of the literature.

Iliac vein aneurysms are extremely rare, even amongst vein aneurysms. We discuss the case of a 26-year-old man with an external iliac vein aneurysm, likely secondary to iatrogenic vascular trauma in the neonatal period. It is the first reported case of an iliac vein aneurysm presenting with lower urinary tract symptoms. Attempts at endovenous management were unsuccessful and therefore the patient underwent open aneurysmectomy. A PubMed literature search revealed a total of nine case reports of iliac vein aneurysms published in English since 2011. We discuss the aetiology, presentation, investigation and management of iliac vein aneurysms and compare to our own case.

Movement, imaging and neurobehavioral assessment as predictors of cerebral palsy in preterm infants.

OBJECTIVE: To study the relative efficacy of three early predictors of cerebral palsy. METHOD: One Hundred and thirty infants with birth weight <1500 g were recruited. Video recordings of spontaneous general movements were made at 36 and 52 weeks postconceptional age. Magnetic resonance imaging and the neurobehavioral assessment of the preterm infant were done at 36 weeks postconceptional age. Follow-up neurological examination and Bayley assessments were made at 18 months corrected age to make early identification of cerebral palsy. RESULTS: Magnetic resonance imaging gave the best specificity and accuracy of 91 and 84% respectively. General movements at 52 weeks showed an improved specificity and accuracy over performance at 36 weeks postconceptional age. The negative predictive value for all methods tested was between 90 and 97%. Combining the results of magnetic resonance imaging and the neurobehavioral assessment improved the sensitivity of prediction to 80%, suggesting that a holistic approach to early detection of cerebral lesions is preferable to a single test. CONCLUSIONS: The majority of infants who appeared to behave within normal limits and exhibit normal brain structure in the newborn period were classified as neurologically intact at follow-up.

PSA testing: an evolving relationship with prostate cancer screening.

PSA testing has made prostate cancer screening a reality for men in many parts of the world, but its benefit for men's health continues to be debated. In men exposed to PSA testing, there has been a well-documented change in the presentation of prostate cancer with a shift towards earlier pathological stage, not without justifiable concern about over-diagnosis by prostate biopsy. Increasingly, men now diagnosed with early stage cancer have previous PSA exposure and are selected for biopsy based on PSA change in relation to cutoff values. Some recent observations suggest that PSA may no longer be an effective marker for early stage tumours, with PSA elevation failing to discriminate tumour-specific characteristics from benign gland enlargement. Traditionally, variation in pathological stage of clinically localised prostate cancer at diagnosis has related to clinical stage, PSA and biopsy Gleason grade, but with distinctions based upon these three assessments declining and an increasing proportion of organ-confined tumours at presentation, new methods of cancer detection and prognostic assessment are now required. Molecular technologies hold great promise in this respect, and in the future biomarker signatures are likely to overshadow total PSA for guiding early diagnosis and prognostic assessment. While arguments about prostate screening will continue, owing not least to its feasibility, future debate is likely to focus increasingly on technological advances and molecular profiling of these notoriously heterogeneous tumours.

Calcification of a Synthetic Renovascular Graft in a Child.

INTRODUCTION: Vascular grafts, especially in paediatric cases, need to be durable. Common failures such as thrombosis are well documented with research efforts directed towards them. However, there are lesser known causes of graft failure, such as graft calcification, and these also require further research focus. REPORT: A paediatric case is described in which a synthetic renovascular graft, implanted for mid-aortic syndrome, became calcified, necessitating surgical intervention to resolve graft malfunction. Significant calcification in the limb of a bifurcated polyethylene terephthalate graft was found to be the cause of resistant stenosis and refractory hypertension. Histology conducted on the explanted limb showed the presence of multinuclear giant cells, indicating a chronic foreign body response. DISCUSSION: Calcification of vascular grafts is probably more common than previously recognised. Stenosis typically resistant to angioplasty may result in the long term and thus leading to surgical intervention. In young children, this is suboptimal as these grafts need to last throughout adulthood. Explanted prosthetic grafts should be sent to specialist registries such as that in Strasbourg to be optimally assessed so that contributory factors can be identified.

Quality of life perception in patients with intractable epilepsy or pseudoseizures.

OBJECTIVES: To contrast and compare self-reported quality of life in patients with intractable epilepsy and pseudoseizures and to examine the relationship between self-reports and objective measures of cognitive functioning in both of these groups. DESIGN: Case series using profile analysis and analysis of covariance. SETTING: University epilepsy surgery program. PARTICIPANTS: Forty-three patients with intractable complex partial seizures of unilateral temporal lobe origin and 25 patients with pseudoseizures. MEASURES: Quality of Life in Epilepsy Inventory-89; neuropsychological tests assessing verbal memory, nonverbal memory, naming, and attention; and the Depression Scale (2) of the MMPI-2 (Minnesota Multiphasic Personality Inventory). RESULTS: Patients with pseudoseizures described themselves as more limited in the physical health domain than patients with complex partial seizures. Self-perceptions of cognitive functioning were similar between groups, despite the superior performance of patients with pseudoseizures on objective measures. Self-perception of cognitive dysfunction was related to mood disorder in the pseudoseizure group only, and there were no relationships between subjective and objective measurements of cognitive status within this group independent of mood disorder. For the complex partial seizures group, relationships between subjective and objective measures of cognitive function were dependent on the side of seizure onset. CONCLUSIONS: Results are consistent with hypotheses that suggest that patients with pseudoseizures focus on physical rather than psychological explanations for stress, and that this focus is related, at least in a subgroup of patients, to mood disorder. Results also provide support for the validity of the Quality of Life in Epilepsy Inventory-89 in populations with intractable seizure disorder, although there is evidence for a possible floor effect on some of the subscales.

Language dominance determined by magnetic source imaging: a comparison with the Wada procedure.

OBJECTIVE: To evaluate the validity of data derived from magnetic source imaging (MSI) regarding cerebral dominance for language in patients with intractable seizure disorder. METHOD: The authors performed functional imaging of the receptive language cortex using a whole-head neuromagnetometer in 26 consecutive epilepsy patients who also underwent the intracarotid amobarbital (Wada) procedure. During MSI recordings, patients engaged in a word recognition task. This task was shown previously to activate language areas in normal adults as well as in patients who undergo intraoperative language mapping, allowing confirmation of MSI findings. Language laterality indices were formed for both the Wada and the MSI procedures. In addition, clinical judgments regarding cerebral dominance for language were made using the two methods by independent raters. RESULTS: Cluster analysis indicated excellent agreement between the quantitative MSI and Wada indices. Rater judgments showed almost complete agreement as well. CONCLUSION: MSI is a promising method for determining cerebral dominance for language.

Skeletal abnormalities in Rett syndrome: increasing evidence for dysmorphogenetic defects.

The presence of metatarsal and metacarpal abnormalities in some individuals has raised the possibility that Rett syndrome is, in fact, a multiple congenital abnormalities/mental retardation (MCA/MR) syndrome. We have conducted radiological examination of 17 cases of Rett syndrome in Western Australia. Short fourth and/or fifth metatarsals were identified in 65% of cases and short fourth and/or fifth metacarpals in 57%. Metatarsal (P = 0.045) and metacarpal (P = 0.006) shortness were significantly more common in girls 14 years or older. Negative ulnar variance (found in 79% of cases) appeared to be independent of age. Reduced bone density in the hands was found in 86% of cases. A nationwide study using the Australian Rett Syndrome Database is planned to follow up these findings and compare them with findings from a control group. The confirmation of these abnormalities in a high proportion of cases may provide morphologic markers to assist in the diagnosis of Rett syndrome and perhaps provide a further avenue of research into the pathogenesis of this disorder.

Nerve growth factor levels in developing rat skin: upregulation following skin wounding.

Levels of nerve growth factor (NGF) in rat hindpaw skin, measured with a sensitive two-site enzyme-linked immunosorbent assay, show two peaks during normal development. The first (57 +/- 5 pg mg-1) occurs at embryonic days (E) 18-20 and coincides with the arrival of axon terminals into the hindpaw skin. The second, larger peak (132 +/- 10 pg mg-1), occurs later, around postnatal day (P) 21 and may be involved in maintenance of neuronal phenotype. Levels outside the two peaks stay relatively constant throughout development (30 pg mg-1). Skin wounding at birth produces a marked increase in NGF levels (149 +/- 25 pg mg-1) which declines after 4 days. This large increase is not observed if wounding is performed at older ages and may underlie the sensory hyperinnervation that accompanies neonatal wounds.

Atypical temporal lobe language representation: MEG and intraoperative stimulation mapping correlation.

Functional brain imaging techniques hold many promises as the methods of choice for identifying areas involved in the execution of language functions. The success of any of these techniques in fulfilling this goal depends upon their ability to produce maps of activated areas that overlap with those obtained through standard invasive procedures such as electrocortical stimulation. This need is particularly acute in cases where active areas are found outside of traditionally defined language areas. In the present report we present two patients who underwent mapping of receptive language areas preoperatively through magnetoencephalography (MEG) and intraoperatively through electrocortical stimulation. Language areas identified by both methods were located in temporoparietal regions as well as in less traditional regions (anterior portion of the superior temporal gyrus and basal temporal cortex). Importantly there was a perfect overlap between the two sets of maps. This clearly demonstrates the validity of MEG-derived maps for identifying cortical areas critically involved in receptive language functions.

Insights into brain function and neural plasticity using magnetic source imaging.

This review outlines the rationale for the use of magnetoencephalography (MEG) or magnetic source imaging (MSI), a noninvasive functional imaging technique, and the features that any imaging method should display to make a substantial contribution to cognitive neuroscience. After a brief discussion of the basic experimental approach used in the authors' studies, the use of early sensory components of brain magnetic responses is reviewed to address issues of the functional organization of the primary sensory cortices, followed by a comment on the clinical use of these components. Second, normative studies focusing on the late components of magnetic responses for establishing the validity and reliability of MSI maps of the language-specific cortex in normal subjects are reviewed. Third, the authors' investigations of fine spatiotemporal features of brain activation maps, specific to receptive language and to reading, are reviewed. Fourth, experience with presurgical mapping of the language-specific cortex in neurosurgery candidates and in patients undergoing the "Wada" procedure is summarized followed by a comment on the perfect agreement of the MSI maps with those derived by more direct invasive brain mapping procedures. Fifth. MSI-derived evidence of often dramatic, functional reorganization of brain areas subserving both simple sensory and linguistic functions is summarized along with comments on the use of MSI as a means for investigating brain plasticity. Finally, in the sixth section of this review, the authors relate their experience with the use of MSI in deriving brain activation profiles during silent reading of real words and pseudowords that are specific to dyslexic children. The review concludes with a discussion on the further use of MSI in assessing, among other issues, the effectiveness of intervention strategies designed to improve reading fluency in dyslexic children.

Localization of language-specific cortex by using magnetic source imaging and electrical stimulation mapping.

OBJECT: In this paper the authors demonstrate the concordance between magnetic source (MS) imaging and direct cortical stimulation for mapping receptive language cortex. METHODS: In 13 consecutive surgical patients, cortex specialized for receptive language functions was identified noninvasively by obtaining activation maps aided by MS imaging in the context of visual and auditory word-recognition tasks. Surgery was then performed for treatment of medically intractable seizure disorder (eight patients), and for resection of tumor (four), or angioma (one). Mapping of language areas with cortical stimulation was performed intraoperatively in 10 patients and extraoperatively in three. Cortical stimulation mapping verified the accuracy of the MS imaging-based localization in all cases. CONCLUSIONS: Information provided by MS imaging can be especially helpful in cases of atypical language representation, including bihemispheric representation, and location of language in areas other than those expected within the dominant hemisphere, such as the anterior portion of the superior temporal gyrus, the posteroinferior portion of the middle temporal gyrus, the basal temporal cortex, and the lateral temporooccipital cortex.

Magnetoencephalographic mapping of the language-specific cortex.

OBJECT: In this paper the authors introduce a novel use of magnetoencephalography (MEG) for noninvasive mapping of language-specific cortex in individual patients and in healthy volunteers. METHODS: The authors describe a series of six experiments in which normative MEG data were collected and the reliability, validity, and topographical accuracy of the data were assessed in patients who had also undergone the Wada procedure or language mapping through intraoperative cortical stimulation. CONCLUSIONS: Findings include: 1) receptive language-specific areas can be reliably activated by simple language tasks and this activation can be readily recorded in short MEG sessions; 2) MEG-derived maps of each individual are reliable because they remain stable over time and are independent of whether auditory or visual stimuli are used to activate the brain; and 3) these maps are also valid because they concur with results of the Wada procedure in assessing hemispheric dominance for language and with the results of cortical stimulation in identifying the precise topography of receptive language regions within the dominant hemisphere. Although the MEG mapping technique should be further refined, it has been shown to be efficacious by correctly identifying the language-dominant hemisphere and specific language-related regions within this hemisphere. Further development of the technique may render it a valuable adjunct for routine presurgical planning in many patients who harbor tumors or have epilepsy.

Language dominance in children as determined by magnetic source imaging and the intracarotid amobarbital procedure: a comparison.

This study evaluated the validity of data derived from magnetic source imaging regarding hemispheric dominance for language in children and adolescents with intractable seizure disorder by comparison with results of the intracarotid amobarbital procedure. Functional imaging of the receptive language cortex using a whole-head neuromagnetometer was performed in 19 consecutive epilepsy patients, ages 8 to 18 years, who also underwent the intracarotid amobarbital procedure. During magnetic source imaging recordings, patients engaged in a continuous recognition memory task for words in visual and auditory modalities. This task has previously been shown to be valid for the purpose of lateralization and localization of language cortex in adult epilepsy patients who undergo the intracarotid amobarbital procedure and intraoperative language mapping allowing confirmation of magnetic source imaging findings. Results indicated that language laterality indices formed for the intracarotid amobarbital procedure and magnetic source imaging procedures were highly correlated (R = .87). In addition, clinical judgments regarding cerebral dominance for language made by independent raters using the two methods were in excellent agreement. We conclude that magnetic source imaging is a promising method for determination of cerebral dominance for language in children and adults.

Brain plasticity for sensory and linguistic functions: a functional imaging study using magnetoencephalography with children and young adults.

In this report, the newest of the functional imaging methods, magnetoencephalography, is described, and its use in addressing the issue of brain reorganization for basic sensory and linguistic functions is documented in a series of 10 children and young adults. These patients presented with a wide variety of conditions, ranging from tumors and focal epilepsy to reading disability. In all cases, clear evidence of reorganization of the brain mechanisms of either somatosensory or linguistic functions or both was obtained, demonstrating the utility of magnetoencephalography in studying, completely noninvasively, the issue of plasticity in the developing brain.