MRI enhances the understanding of critical anatomy during primary laparoscopic port placement.

Despite the majority of laparoscopic visceral injuries occurring with primary entry, high-fidelity training models are lacking. Three healthy volunteers underwent non-contrast 3T MRI at Edinburgh Imaging. A direct entry 12mm trocar was filled with water to improve MR visibility, placed on the skin at entry points, then images were acquired in the supine position. Composite images were created, and distances from the trocar tip to the viscera were measured, demonstrating anatomical relationships during laparoscopic entry. With a BMI of 21 kg/m2, gentle downward pressure during skin incision or trocar entry reduced the distance to the aorta to less than the length of a No. 11 Scalpel blade (22mm). The need for counter-traction and stabilisation of the abdominal wall during incision and entry is demonstrated. With a BMI of 38 kg/m2, deviating from the vertical angle for trocar insertion can result in the entire trocar shaft being placed within the abdominal wall without entering the peritoneum, creating a 'failed entry.' At Palmer's point distance between the skin and bowel is only 20mm. Ensuring the stomach is not distended will minimise gastric injury risk. The use of MRI to provide visualisation of the critical anatomy during primary port entry allows the surgeon to gain better understanding of textually described best practice techniques.

Repeatability and reproducibility of cardiac manganese-enhanced magnetic resonance imaging.

Manganese-enhanced magnetic resonance imaging can provide a surrogate measure of myocardial calcium handling. Its repeatability and reproducibility are currently unknown. Sixty-eight participants: 20 healthy volunteers, 20 with acute myocardial infarction, 18 with hypertrophic and 10 with non-ischemic dilated cardiomyopathy underwent manganese-enhanced magnetic resonance imaging. Ten healthy volunteers were re-scanned at 3 months. Native T1 values and myocardial manganese uptake were assessed for intra and inter-observer repeatability. Scan-rescan reproducibility was assessed in ten healthy volunteers. Intra-observer and inter-observer correlation was excellent in healthy volunteers for mean native T1 mapping [Lin's correlation coefficient (LCC) 0.97 and 0.97 respectively] and myocardial manganese uptake (LCC: 0.99 and 0.96 respectively). Scan-rescan correlation for native T1 and myocardial manganese uptake was also excellent. Similarly, intra-observer correlations for native T1 and myocardial manganese uptake in patients with acute myocardial infarction (LCC: 0.97 and 0.97 respectively), hypertrophic (LCC: 0.98 and 0.97 respectively) and dilated cardiomyopathy (LCC: 0.99 and 0.95 respectively) were excellent. Limits of agreement were broader in patients with dilated cardiomyopathy. Manganese-enhanced magnetic resonance imaging has high repeatability and reproducibility in healthy myocardium and high repeatability in diseased myocardium. However, further study is needed to establish robustness in pathologies with diffuse myocardial fibrosis.

Markers of human endometrial hypoxia can be detected in vivo and ex vivo during physiological menstruation.

STUDY QUESTION: Can markers of human endometrial hypoxia be detected at menstruation in vivo? SUMMARY ANSWER: Our in vivo data support the presence of hypoxia in menstrual endometrium of women during physiological menstruation. WHAT IS KNOWN ALREADY: Current evidence from animal models and human in vitro studies suggests endometrial hypoxia is present at menstruation and drives endometrial repair post menses. However, detection of human endometrial hypoxia in vivo remains elusive. STUDY DESIGN, SIZE, DURATION: We performed a prospective case study of 16 women with normal menstrual bleeding. PARTICIPANTS/MATERIALS, SETTING, METHODS: Reproductively aged female participants with a regular menstrual cycle underwent objective measurement of their menstrual blood loss using the alkaline haematin method to confirm a loss of <80 ml per cycle. Exclusion criteria were exogenous hormone use, an intrauterine device, endometriosis or fibroids >3 cm. Participants attended for two MRI scans; during days 1-3 of menstruation and the early/mid-secretory phase of their cycle. The MRI protocol included dynamic contrast-enhanced MRI and T2* quantification. At each visit, an endometrial sample was also collected and hypoxia-regulated repair factor mRNA levels (ADM, VEGFA, CXCR4) were quantified by RT-qPCR. MAIN RESULTS AND THE ROLE OF CHANCE: Women had reduced T2* during menstrual scans versus non-menstrual scans (P = 0.005), consistent with menstrual hypoxia. Plasma flow (Fp) was increased at menstruation compared to the non-menstrual phase (P = 0.0005). Laboratory findings revealed increased ADM, VEGF-A and CXCR4 at menstruation on examination of paired endometrial biopsies from the menstrual and non-menstrual phase (P = 0.008; P = 0.03; P = 0.009). There was a significant correlation between T2* and these ex vivo hypoxic markers (P < 0.05). LIMITATIONS, REASONS FOR CAUTION: This study examined the in vivo detection of endometrial hypoxic markers at specific timepoints in the menstrual cycle in women with a menstrual blood loss <80 ml/cycle and without significant uterine structural abnormalities. Further research is required to determine the presence of endometrial hypoxia in those experiencing abnormal uterine bleeding with and without fibroids/adenomyosis. WIDER IMPLICATIONS OF THE FINDINGS: Heavy menstrual bleeding (HMB) is a common, debilitating condition. Understanding menstrual physiology may improve therapeutics. To our knowledge, this is the first in vivo data supporting the presence of menstrual hypoxia in the endometrium of women with normal menstrual bleeding. If aberrant in those with HMB, these non-invasive tests may aid diagnosis and facilitate personalized treatments for HMB. STUDY FUNDING/COMPETING INTEREST(S): This work was funded by Wellbeing of Women grant RG1820, Wellcome Trust Fellowship 209589/Z/17/Z and undertaken in the MRC Centre for Reproductive Health, funded by grants G1002033 and MR/N022556/1. H.O.D.C. has clinical research support for laboratory consumables and staff from Bayer AG and provides consultancy advice (but with no personal remuneration) for Bayer AG, PregLem SA, Gedeon Richter, Vifor Pharma UK Ltd, AbbVie Inc; Myovant Sciences GmbH. H.O.D.C. receives royalties from UpToDate for articles on abnormal uterine bleeding. TRIAL REGISTRATION NUMBER: N/A.

Manganese-enhanced magnetic resonance imaging in dilated cardiomyopathy and hypertrophic cardiomyopathy.

AIMS: The aim of this study is to quantify altered myocardial calcium handling in non-ischaemic cardiomyopathy using magnetic resonance imaging. METHODS AND RESULTS: Patients with dilated cardiomyopathy (n = 10) or hypertrophic cardiomyopathy (n = 17) underwent both gadolinium and manganese contrast-enhanced magnetic resonance imaging and were compared with healthy volunteers (n = 20). Differential manganese uptake (Ki) was assessed using a two-compartment Patlak model. Compared with healthy volunteers, reduction in T1 with manganese-enhanced magnetic resonance imaging was lower in patients with dilated cardiomyopathy [mean reduction 257 ± 45 (21%) vs. 288 ± 34 (26%) ms, P < 0.001], with higher T1 at 40 min (948 ± 57 vs. 834 ± 28 ms, P < 0.0001). In patients with hypertrophic cardiomyopathy, reductions in T1 were less than healthy volunteers [mean reduction 251 ± 86 (18%) and 277 ± 34 (23%) vs. 288 ± 34 (26%) ms, with and without fibrosis respectively, P < 0.001]. Myocardial manganese uptake was modelled, rate of uptake was reduced in both dilated and hypertrophic cardiomyopathy in comparison with healthy volunteers (mean Ki 19 ± 4, 19 ± 3, and 23 ± 4 mL/100 g/min, respectively; P = 0.0068). In patients with dilated cardiomyopathy, manganese uptake rate correlated with left ventricular ejection fraction (r2 = 0.61, P = 0.009). Rate of myocardial manganese uptake demonstrated stepwise reductions across healthy myocardium, hypertrophic cardiomyopathy without fibrosis and hypertrophic cardiomyopathy with fibrosis providing absolute discrimination between the healthy myocardium and fibrosed myocardium (mean Ki 23 ± 4, 19 ± 3, and 13 ± 4 mL/100 g/min, respectively; P < 0.0001). CONCLUSION: The rate of manganese uptake in both dilated and hypertrophic cardiomyopathy provides a measure of altered myocardial calcium handling. This holds major promise for the detection and monitoring of dysfunctional myocardium, with the potential for early intervention and prognostication.

MRI-guided prostate adaptive radiotherapy - A systematic review.

Dose escalated radiotherapy improves outcomes for men with prostate cancer. A plateau for benefit from dose escalation using EBRT may not have been reached for some patients with higher risk disease. The use of increasingly conformal techniques, such as step and shoot IMRT or more recently VMAT, has allowed treatment intensification to be achieved whilst minimising associated increases in toxicity to surrounding normal structures. To support further safe dose escalation, the uncertainties in the treatment target position will need be minimised using optimal planning and image-guided radiotherapy (IGRT). In particular the increasing usage of profoundly hypo-fractionated stereotactic therapy is predicated on the ability to confidently direct treatment precisely to the intended target for the duration of each treatment. This article reviews published studies on the influences of varies types of motion on daily prostate position and how these may be mitigated to improve IGRT in future. In particular the role that MRI has played in the generation of data is discussed and the potential role of the MR-Linac in next-generation IGRT is discussed.

High-resolution magnetic resonance cholangiography (MRC) with adaptive averaging: diagnostic performance evaluation.

AIM: To evaluate the diagnostic performance of an interactive, adaptively averaged (AA) two-dimensional (2D) magnetic resonance cholangiography (MRC) technique in patients with suspected biliary disease by comparison to the standard MRC technique. MATERIALS AND METHODS: The AA 2D MRC method registers the images after acquisition, allowing summation of multiple images to improve the signal:noise ratio (SNR) and thereby potentially improve the visualization of bile ducts. One hundred and twenty-eight patients underwent both 2D conventional and AA magnetic resonance cholangiopancreatography (MRCP). Twenty-seven patients were excluded from the analysis as AA images could not be properly obtained due to technical failures. All examinations were performed using a 1.5 T whole-body MR system and a four-channel torso phased array coil. Images of 101 patients were adaptively averaged using an in-house developed program written in IDL. Two readers qualitatively evaluated the studies in consensus, blinded to acquisition details and without knowledge of clinical information. RESULTS: The AA technique was significantly better than the conventional 2D MRC for the visualization of the second-order branch intrahepatic ducts (p<00001). Overall, there was no significant difference in the diagnostic confidence between two techniques (p=0.12). However, the AA technique showed a trend towards more confident diagnosis of biliary strictures (p=0.055), likely due to better diagnostic confidence in identifying second order branch intrahepatic duct strictures (p=0.054). CONCLUSION: Excluding those patients those patients in whom either satisfactory respiratory gating or a suitable kernel placement was not achieved, AA 2D MRC demonstrated a significant improvement in visualization of intrahepatic duct branches compared to standard MRC.

Ultrasound diagnosis of lower limb deep venous thrombosis.

Venous ultrasound imaging was compared with ascending contrast venography for the diagnosis of suspected deep vein thrombosis (DVT) in the femoral, popliteal and calf vein segments of 44 limbs in 44 patients. One femoral and one calf vein segment could not be imaged (1.5% of the segments examined), but during the same period venography failed in six patients because of an inability to cannulate a swollen limb. Ultrasound imaging compared with venography as a means of diagnosing DVT showed an overall sensitivity of 95% and a specificity of 92%. The sensitivity and specificity of ultrasound imaging for the diagnosis of both femoral and popliteal vein thromboses were 100% and 97%, respectively, and for calf vein thrombosis were 85% and 83%, respectively. This study supports the recommendation that ultrasound imaging is now the investigation of choice for the diagnosis of DVT provided that the scan is performed by an experienced vascular technologist. Ultrasound imaging may also define other pathological conditions presenting in the differential diagnosis of DVT, such as superficial thrombophlebitis and Baker's cyst.

Noninvasive imaging of the superficial femoral artery using ultrasound Duplex scanning.

A total of 56 lower extremities in 28 patients were evaluated by both conventional arteriography and ultrasound duplex scanning. Overall sensitivity for duplex scanning compared to arteriography in detecting stenotic or occlusive disease was 91%, specificity was 94%, positive predictive value 85% and negative predictive value 97%. Results for Duplex scanning were better in the proximal and middle segment compared to the distal third of the superficial femoral artery. The sensitivity of segmental lower extremity pressures and pulse volume recordings for predicting proximal superficial femoral artery disease compared to arteriography was 82%; specificity was 79% and accuracy 80%, all inferior to that of Duplex scanning. Duplex scanning is a promising technique suitable for noninvasive assessment of patients presenting with suspected superficial femoral artery disease. It should readily identify candidates for percutaneous interventional techniques in which a patent segment of proximal superficial femoral artery is required for access. It will also be useful in follow-up studies of patency of the superficial femoral artery following interventional procedures such as balloon dilatation and laser angioplasty.

Risk of aortic aneurysm surgery as assessed by preoperative gated heart pool scan.

Gated heart pool scan measuring left ventricular ejection fraction (LVEF) was performed preoperatively in 72 patients presenting for elective repair of abdominal aortic aneurysm. Patients with a positive cardiac history were more likely to have a LVEF of less than or equal to 45 per cent (P less than 0.001). The operative mortality rate was 4 per cent. Each of three patients who died had a LVEF less than or equal to 35 per cent and developed cardiac failure which led to renal failure. Five other patients developed cardiac failure manifested by acute pulmonary oedema during the early postoperative period. There was no statistically significant association between a positive cardiac history and the occurrence of postoperative cardiac failure or death. However, patients with a LVEF of less than or equal to 45 per cent were more likely to develop postoperative cardiac failure (P = 0.004) while patients with a LVEF of less than or equal to 35 per cent had a greater chance of dying (P less than 0.001). No patient died with a LVEF greater than 35 per cent. Preoperative evaluation of LVEF can select patients at high risk of cardiac death from repair of abdominal aortic aneurysm. Such patients could be followed conservatively if they remain asymptomatic and the aneurysm does not enlarge. If operation is considered mandatory, patients with a low LVEF should receive intensive perioperative monitoring with enhancement of ventricular performance.

Dipyridamole-thallium scan for screening of coronary artery disease prior to vascular surgery.

Patients with extracranial cerebrovascular disease and peripheral vascular disease are at increased risk of ischaemic heart disease with resulting increased risk of early and late mortality following vascular reconstruction. Over a two year period, 67 patients undergoing carotid or aortic surgery were investigated preoperatively with dipyridamole-thallium scan. There were three positive scans in the first 17 patients; two of these patients suffered a postoperative myocardial infarction (one fatal), compared to none of 14 who had a negative scan (p = 0.02). There were seven positive scans in the next 50 patients. Patients with left main trunk or triple vessel disease were recommended to have coronary artery bypass prior to or combined with the vascular reconstruction. There were no deaths or postoperative myocardial infarction in this group, this improvement in morbidity being statistically significant (p = 0.01). Dipyridamole-thallium scanning is an effective screening procedure for coronary artery disease. Patients with a positive scan are at increased risk of postoperative myocardial infarction following vascular reconstruction. Further investigation with coronary arteriography prior to vascular reconstruction is recommended in patients with positive scans. Coronary artery bypass should be performed prior to or combined with the vascular reconstruction in patients with left main trunk or triple vessel disease.

Outcome in patients with failed percutaneous transluminal angioplasty for peripheral vascular disease.

The outcome in 299 patients having 321 percutaneous transluminal angioplasty (PTA) procedures for peripheral vascular disease was analysed. Technical failure occurred in 21 patients (7%) but in none was the limb ischemia made worse by the failed PTA attempt; nine of these (3%) had been considered unsuitable for arterial reconstruction and proceeded to primary amputation, while 12 (4%) did not have subsequent management compromised by the failed PTA attempt. Complications occurred in seven patients (2.3%); four of these (1.3%) had worsening ischemia but were able to be satisfactorily managed by surgical intervention. There were 71 patients (23.7%) who had an initially successful PTA procedure which subsequently failed; 20 of these (6.7%) had been considered unsuitable for arterial reconstruction and proceeded to amputation, while five patients suitable for arterial reconstruction (1.7%) came to amputation, four following failed bypass surgery and one following multiple trauma from a motor vehicle accident. The remaining 46 patients (15.3%) did not have subsequent management compromised by the late failure of PTA. Early and late failure of PTA in patients presenting with peripheral vascular disease does not compromise subsequent management.

EEG monitoring during carotid endarterectomy.

One hundred and thirty-one patients undergoing 142 carotid endarterectomy procedures were randomized to have their operation performed either with or without intra-operative electroencephalographic (EEG) monitoring. Patients with EEG monitoring were shunted if both the internal carotid back pressure (ICBP) was less than 50 mmHg and ipsilateral change was evident on the EEG after clamping. Patients without EEG monitoring were shunted if ICBP was less than 50 mmHg. There one postoperative death (0.7%) with neurological deficits occurring in five patients (3.5%). There were significantly fewer neurological deficits (P = 0.02) in patients with no EEG change (one of 59) compared with those with EEG change (two of 13). There was a highly significant increase (P = 0.005) in incidence of neurological deficit (two of five patients) when ICBP was considered 'adequate' at 50 mmHg or greater but EEG change occurred. No neurological deficit occurred in 14 patients who were not shunted with ICBP less than 50 mmHg but with no EEG change. There was no difference in the incidence of neurological deficit in patients with low and high ICBP when both 50 and 55 mmHg were used as the cut-off points. It is concluded that EEG monitoring is useful in identifying patients requiring shunting during carotid endarterectomy. Use of a shunt is recommended if there is EEG change regardless of ICBP; conversely, if ICBP is low but there is no EEG change it would appear safe to proceed without shunting.

The changing pattern of vascular surgery: the effect of percutaneous transluminal angioplasty.

The pattern of vascular surgery at Westmead Hospital from 1979 to 1985 has been reviewed. There has been an upward trend in the number of patients having repair of abdominal aortic aneurysm and carotid endarterectomy. However, the number of operations for peripheral vascular disease has not increased. This may be due to the increasing use of percutaneous transluminal angioplasty (PTA), but it may also be associated with the increasing difficulty in obtaining hospital admission for patients with conditions not immediately life or limb threatening.