Thoracic aortic microcalcification activity in combined positron emission tomography and magnetic resonance imaging.

INTRODUCTION: Non-invasive detection of pathological changes in thoracic aortic disease remains an unmet clinical need particularly for patients with congenital heart disease. Positron emission tomography combined with magnetic resonance imaging (PET-MRI) could provide a valuable low-radiation method of aortic surveillance in high-risk groups. Quantification of aortic microcalcification activity using sodium [18F]fluoride holds promise in the assessment of thoracic aortopathies. We sought to evaluate aortic sodium [18F]fluoride uptake in PET-MRI using three methods of attenuation correction compared to positron emission tomography computed tomography (PET-CT) in patients with bicuspid aortic valve, METHODS: Thirty asymptomatic patients under surveillance for bicuspid aortic valve disease underwent sodium [18F]fluoride PET-CT and PET-MRI of the ascending thoracic aorta during a single visit. PET-MRI data were reconstructed using three iterations of attenuation correction (Dixon, radial gradient recalled echo with two [RadialVIBE-2] or four [RadialVIBE-4] tissue segmentation). Images were qualitatively and quantitatively analysed for aortic sodium [18F]fluoride uptake on PET-CT and PET-MRI. RESULTS: Aortic sodium [18F]fluoride uptake on PET-MRI was visually comparable with PET-CT using each reconstruction and total aortic standardised uptake values on PET-CT strongly correlated with each PET-MRI attenuation correction method (Dixon R = 0.70; RadialVIBE-2 R = 0.63; RadialVIBE-4 R = 0.64; p < 0.001 for all). Breathing related artefact between soft tissue and lung were detected using Dixon and RadialVIBE-4 but not RadialVIBE-2 reconstructions, with the presence of this artefact adjacent to the atria leading to variations in blood pool activity estimates. Consequently, quantitative agreements between radiotracer activity on PET-CT and PET-MRI were most consistent with RadialVIBE-2. CONCLUSION: Ascending aortic microcalcification analysis in PET-MRI is feasible with comparable findings to PET-CT. RadialVIBE-2 tissue attenuation correction correlates best with the reference standard of PET-CT and is less susceptible to artefact. There remain challenges in segmenting tissue types in PET-MRI reconstructions, and improved attenuation correction methods are required.

18F-Sodium Fluoride Positron Emission Tomography and Computed Tomography in Acute Aortic Syndrome.

BACKGROUND: Acute aortic syndrome is associated with aortic medial degeneration. 18F-sodium fluoride (18F-NaF) positron emission tomography (PET) detects microscopic tissue calcification as a marker of disease activity. OBJECTIVES: In a proof-of-concept study, this investigation aimed to establish whether 18F-NaF PET combined with computed tomography (CT) angiography could identify aortic medial disease activity in patients with acute aortic syndrome. METHODS: Patients with aortic dissection or intramural hematomas and control subjects underwent 18F-NaF PET/CT angiography of the aorta. Aortic 18F-NaF uptake was measured at the most diseased segment, and the maximum value was corrected for background blood pool activity (maximum tissue-to-background ratio [TBRmax]). Radiotracer uptake was compared with change in aortic size and major adverse aortic events (aortic rupture, aorta-related death, or aortic repair) over 45 ± 13 months. RESULTS: Aortic 18F-NaF uptake co-localized with histologically defined regions of microcalcification and elastin disruption. Compared with control subjects, patients with acute aortic syndrome had increased 18F-NaF uptake (TBRmax: 1.36 ± 0.39 [n = 20] vs 2.02 ± 0.42 [n = 47] respectively; P < 0.001) with enhanced uptake at the site of intimal disruption (+27.5%; P < 0.001). 18F-NaF uptake in the false lumen was associated with aortic growth (+7.1 mm/year; P = 0.011), and uptake in the outer aortic wall was associated with major adverse aortic events (HR: 8.5 [95% CI: 1.4-50.4]; P = 0.019). CONCLUSIONS: In patients with acute aortic syndrome, 18F-NaF uptake was enhanced at sites of disease activity and was associated with aortic growth and clinical events. 18F-NaF PET/CT holds promise as a noninvasive marker of disease severity and future risk in patients with acute aortic syndrome. (18F Sodium Fluoride PET/CT in Acute Aortic Syndrome [FAASt]; NCT03647566).

18F-NaF PET/MRI for Detection of Carotid Atheroma in Acute Neurovascular Syndrome.

Background MRI and fluorine 18-labeled sodium fluoride (18F-NaF) PET can be used to identify features of plaque instability, rupture, and disease activity, but large studies have not been performed. Purpose To evaluate the association between 18F-NaF activity and culprit carotid plaque in acute neurovascular syndrome. Materials and Methods In this prospective observational cohort study (October 2017 to January 2020), participants underwent 18F-NaF PET/MRI. An experienced clinician determined the culprit carotid artery based on symptoms and record review. 18F-NaF uptake was quantified using standardized uptake values and tissue-to-background ratios. Statistical significance was assessed with the Welch, χ2, Wilcoxon, or Fisher test. Multivariable models were used to evaluate the relationship between the imaging markers and the culprit versus nonculprit vessel. Results A total of 110 participants were evaluated (mean age, 68 years ± 10 [SD]; 70 men and 40 women). Of the 110, 34 (32%) had prior cerebrovascular disease, and 26 (24%) presented with amaurosis fugax, 54 (49%) with transient ischemic attack, and 30 (27%) with stroke. Compared with nonculprit carotids, culprit carotids had greater stenoses (≥50% stenosis: 30% vs 15% [P = .02]; ≥70% stenosis: 25% vs 4.5% [P < .001]) and had increased prevalence of MRI-derived adverse plaque features, including intraplaque hemorrhage (42% vs 23%; P = .004), necrotic core (36% vs 18%; P = .004), thrombus (7.3% vs 0%; P = .01), ulceration (18% vs 3.6%; P = .001), and higher 18F-NaF uptake (maximum tissue-to-background ratio, 1.38 [IQR, 1.12-1.82] vs 1.26 [IQR, 0.99-1.66], respectively; P = .04). Higher 18F-NaF uptake was positively associated with necrosis, intraplaque hemorrhage, ulceration, and calcification and inversely associated with fibrosis (P = .04 to P < .001). In multivariable analysis, carotid stenosis at or over 70% (odds ratio, 5.72 [95% CI: 2.2, 18]) and MRI-derived adverse plaque characteristics (odds ratio, 2.16 [95% CI: 1.2, 3.9]) were both associated with the culprit versus nonculprit carotid vessel. Conclusion Fluorine 18-labeled sodium fluoride PET/MRI characteristics were associated with the culprit carotid vessel in study participants with acute neurovascular syndrome. Clinical trial registration no. NCT03215550 and NCT03215563 © RSNA, 2022 Online supplemental material is available for this article.

Thoracic Aortic 18F-Sodium Fluoride Activity and Ischemic Stroke in Patients With Established Cardiovascular Disease.

BACKGROUND: Aortic atherosclerosis represents an important contributor to ischemic stroke risk. Identifying patients with high-risk aortic atheroma could improve preventative treatment strategies for future ischemic stroke. OBJECTIVES: The purpose of this study was to investigate whether thoracic 18F-sodium fluoride positron emission tomography (PET) could improve the identification of patients at the highest risk of ischemic stroke. METHODS: In a post hoc observational cohort study, we quantified thoracic aortic and coronary 18F-sodium fluoride activity in 461 patients with stable cardiovascular disease undergoing PET combined with computed tomography (CT). Progression of atherosclerosis was assessed by change in aortic and coronary CT calcium volume. Clinical outcomes were determined by the occurrence of ischemic stroke and myocardial infarction. We compared the prognostic utility of 18F-sodium fluoride activity for predicting stroke to clinical risk scores and CT calcium quantification using survival analysis and multivariable Cox regression. RESULTS: After 12.7 ± 2.7 months, progression of thoracic aortic calcium volume correlated with baseline thoracic aortic 18F-sodium fluoride activity (n = 140; r = 0.31; P = 0.00016). In 461 patients, 23 (5%) patients experienced an ischemic stroke and 32 (7%) a myocardial infarction after 6.1 ± 2.3 years of follow-up. High thoracic aortic 18F-sodium fluoride activity was strongly associated with ischemic stroke (HR: 10.3 [95% CI: 3.1-34.8]; P = 0.00017), but not myocardial infarction (P = 0.40). Conversely, high coronary 18F-sodium fluoride activity was associated with myocardial infarction (HR: 4.8 [95% CI: 1.9-12.2]; P = 0.00095) but not ischemic stroke (P = 0.39). In a multivariable Cox regression model including imaging and clinical risk factors, thoracic aortic 18F-sodium fluoride activity was the only variable associated with ischemic stroke (HR: 8.19 [95% CI: 2.33-28.7], P = 0.0010). CONCLUSIONS: In patients with established cardiovascular disease, thoracic aortic 18F-sodium fluoride activity is associated with the progression of atherosclerosis and future ischemic stroke. Arterial 18F-sodium fluoride activity identifies localized areas of atherosclerotic disease activity that are directly linked to disease progression and downstream regional clinical atherothrombotic events. (DIAMOND-Dual Antiplatelet Therapy to Reduce Myocardial Injury [DIAMOND], NCT02110303; Study Investigating the Effect of Drugs Used to Treat Osteoporosis on the Progression of Calcific Aortic Stenosis [SALTIRE II], NCT02132026; Novel Imaging Approaches To Identify Unstable Coronary Plaques, NCT01749254; and Role of Active Valvular Calcification and Inflammation in Patients With Aortic Stenosis, NCT01358513).

Osteocalcin Regulates Arterial Calcification Via Altered Wnt Signaling and Glucose Metabolism.

Arterial calcification is an important hallmark of cardiovascular disease and shares many similarities with skeletal mineralization. The bone-specific protein osteocalcin (OCN) is an established marker of vascular smooth muscle cell (VSMC) osteochondrogenic transdifferentiation and a known regulator of glucose metabolism. However, the role of OCN in controlling arterial calcification is unclear. We hypothesized that OCN regulates calcification in VSMCs and sought to identify the underpinning signaling pathways. Immunohistochemistry revealed OCN co-localization with VSMC calcification in human calcified carotid artery plaques. Additionally, 3 mM phosphate treatment stimulated OCN mRNA expression in cultured VSMCs (1.72-fold, p < 0.001). Phosphate-induced calcification was blunted in VSMCs derived from OCN null mice (Ocn -/- ) compared with cells derived from wild-type (WT) mice (0.37-fold, p < 0.001). Ocn -/- VSMCs showed reduced mRNA expression of the osteogenic marker Runx2 (0.51-fold, p < 0.01) and the sodium-dependent phosphate transporter, PiT1 (0.70-fold, p < 0.001), with an increase in the calcification inhibitor Mgp (1.42-fold, p < 0.05) compared with WT. Ocn -/- VSMCs also showed reduced mRNA expression of Axin2 (0.13-fold, p < 0.001) and Cyclin D (0.71 fold, p < 0.01), markers of Wnt signaling. CHIR99021 (GSK3ß inhibitor) treatment increased calcium deposition in WT and Ocn -/- VSMCs (1 µM, p < 0.001). Ocn -/- VSMCs, however, calcified less than WT cells (1 µM; 0.27-fold, p < 0.001). Ocn -/- VSMCs showed reduced mRNA expression of Glut1 (0.78-fold, p < 0.001), Hex1 (0.77-fold, p < 0.01), and Pdk4 (0.47-fold, p < 0.001). This was accompanied by reduced glucose uptake (0.38-fold, p < 0.05). Subsequent mitochondrial function assessment revealed increased ATP-linked respiration (1.29-fold, p < 0.05), spare respiratory capacity (1.59-fold, p < 0.01), and maximal respiration (1.52-fold, p < 0.001) in Ocn -/- versus WT VSMCs. Together these data suggest that OCN plays a crucial role in arterial calcification mediated by Wnt/ß-catenin signaling through reduced maximal respiration. Mitochondrial dynamics may therefore represent a novel therapeutic target for clinical intervention. © 2019 American Society for Bone and Mineral Research.

Novel Plaque Enriched Long Noncoding RNA in Atherosclerotic Macrophage Regulation (PELATON).

OBJECTIVE: Long noncoding RNAs (lncRNAs) are an emergent class of molecules with diverse functional roles, widely expressed in human physiology and disease. Although some lncRNAs have been identified in cardiovascular disease, their potential as novel targets in the prevention of atherosclerosis is unknown. We set out to discover important lncRNAs in unstable plaque and gain insight into their functional relevance. Approach and Results: Analysis of RNA sequencing previously performed on stable and unstable atherosclerotic plaque identified a panel of 47 differentially regulated lncRNAs. We focused on LINC01272, a lncRNA upregulated in unstable plaque previously detected in inflammatory bowel disease, which we termed PELATON (plaque enriched lncRNA in atherosclerotic and inflammatory bowel macrophage regulation). Here, we demonstrate that PELATON is highly monocyte- and macrophage-specific across vascular cell types, and almost entirely nuclear by cellular fractionation (90%-98%). In situ hybridization confirmed enrichment of PELATON in areas of plaque inflammation, colocalizing with macrophages around the shoulders and necrotic core of human plaque sections. Consistent with its nuclear localization, and despite containing a predicted open reading frame, PELATON did not demonstrate any protein-coding potential in vitro. Functionally, knockdown of PELATON significantly reduced phagocytosis, lipid uptake and reactive oxygen species production in high-content analysis, with a significant reduction in phagocytosis independently validated. Furthermore, CD36, a key mediator of phagocytic oxLDL (oxidized low-density lipoprotein) uptake was significantly reduced with PELATON knockdown. CONCLUSIONS: PELATON is a nuclear expressed, monocyte- and macrophage-specific lncRNA, upregulated in unstable atherosclerotic plaque. Knockdown of PELATON affects cellular functions associated with plaque progression.

Emerging techniques in atherosclerosis imaging.

Atherosclerosis is a chronic immunomodulated disease that affects multiple vascular beds and results in a significant worldwide disease burden. Conventional imaging modalities focus on the morphological features of atherosclerotic disease such as the degree of stenosis caused by a lesion. Modern CT, MR and positron emission tomography scanners have seen significant improvements in the rapidity of image acquisition and spatial resolution. This has increased the scope for the clinical application of these modalities. Multimodality imaging can improve cardiovascular risk prediction by informing on the constituency and metabolic processes within the vessel wall. Specific disease processes can be targeted using novel biological tracers and "smart" contrast agents. These approaches have the potential to inform clinicians of the metabolic state of atherosclerotic plaque. This review will provide an overview of current imaging techniques for the imaging of atherosclerosis and how various modalities can provide information that enhances the depiction of basic morphology.

The Human-Specific and Smooth Muscle Cell-Enriched LncRNA SMILR Promotes Proliferation by Regulating Mitotic CENPF mRNA and Drives Cell-Cycle Progression Which Can Be Targeted to Limit Vascular Remodeling.

RATIONALE: In response to blood vessel wall injury, aberrant proliferation of vascular smooth muscle cells (SMCs) causes pathological remodeling. However, the controlling mechanisms are not completely understood. OBJECTIVE: We recently showed that the human long noncoding RNA, SMILR, promotes vascular SMCs proliferation by a hitherto unknown mechanism. Here, we assess the therapeutic potential of SMILR inhibition and detail the molecular mechanism of action. METHODS AND RESULTS: We used deep RNA-sequencing of human saphenous vein SMCs stimulated with IL (interleukin)-1α and PDGF (platelet-derived growth factor)-BB with SMILR knockdown (siRNA) or overexpression (lentivirus), to identify SMILR-regulated genes. This revealed a SMILR-dependent network essential for cell cycle progression. In particular, we found using the fluorescent ubiquitination-based cell cycle indicator viral system that SMILR regulates the late mitotic phase of the cell cycle and cytokinesis with SMILR knockdown resulting in ≈10% increase in binucleated cells. SMILR pulldowns further revealed its potential molecular mechanism, which involves an interaction with the mRNA of the late mitotic protein CENPF (centromere protein F) and the regulatory Staufen1 RNA-binding protein. SMILR and this downstream axis were also found to be activated in the human ex vivo vein graft pathological model and in primary human coronary artery SMCs and atherosclerotic plaques obtained at carotid endarterectomy. Finally, to assess the therapeutic potential of SMILR, we used a novel siRNA approach in the ex vivo vein graft model (within the 30 minutes clinical time frame that would occur between harvest and implant) to assess the reduction of proliferation by EdU incorporation. SMILR knockdown led to a marked decrease in proliferation from ≈29% in controls to ≈5% with SMILR depletion. CONCLUSIONS: Collectively, we demonstrate that SMILR is a critical mediator of vascular SMC proliferation via direct regulation of mitotic progression. Our data further reveal a potential SMILR-targeting intervention to limit atherogenesis and adverse vascular remodeling.

Reproducibility of Transcranial Doppler ultrasound in the middle cerebral artery.

BACKGROUND: Transcranial Doppler ultrasound remains the only imaging modality that is capable of real-time measurements of blood flow velocity and microembolic signals in the cerebral circulation. We here assessed the repeatability and reproducibility of transcranial Doppler ultrasound in healthy volunteers and patients with symptomatic carotid artery stenosis. METHODS: Between March and August 2017, we recruited 20 healthy volunteers and 20 patients with symptomatic carotid artery stenosis. In a quiet temperature-controlled room, two 1-h transcranial Doppler measurements of blood flow velocities and microembolic signals were performed sequentially on the same day (within-day repeatability) and a third 7-14 days later (between-day reproducibility). Levels of agreement were assessed by interclass correlation co-efficient. RESULTS: In healthy volunteers (31±9 years, 11 male), within-day repeatability of Doppler measurements were 0.880 (95% CI 0.726-0.950) for peak velocity, 0.867 (95% CI 0.700-0.945) for mean velocity, and 0.887 (95% CI 0.741-0.953) for end-diastolic velocity. Between-day reproducibility was similar but lower: 0.777 (95% CI 0.526-0.905), 0.795 (95% CI 0.558-0.913), and 0.674 (95% CI 0.349-0.856) respectively. In patients (72±11 years, 11 male), within-day repeatability of Doppler measurements were higher: 0.926 (95% CI 0.826-0.970) for peak velocity, 0.922 (95% CI 0.817-0.968) for mean velocity, and 0.868 (95% CI 0.701-0.945) for end-diastolic velocity. Similarly, between-day reproducibility revealed lower values: 0.800 (95% CI 0.567-0.915), 0.786 (95% CI 0.542-0.909), and 0.778 (95% CI 0.527-0.905) respectively. In both cohorts, the intra-observer Bland Altman analysis demonstrated acceptable mean measurement differences and limits of agreement between series of middle cerebral artery velocity measurements with very few outliers. In patients, the carotid stenoses were 30-40% (n = 9), 40-50% (n = 6), 50-70% (n = 3) and > 70% (n = 2). No spontaneous embolisation was detected in either of the groups. CONCLUSIONS: Transcranial Doppler generates reproducible data regarding the middle cerebral artery velocities. However, larger studies are needed to validate its clinical applicability. TRIAL REGISTRATION: ClinicalTrial.gov (ID NCT 03050567), retrospectively registered on 15/05/2017.

18F-Sodium Fluoride Uptake in Abdominal Aortic Aneurysms: The SoFIA3 Study.

BACKGROUND: Fluorine-18-sodium fluoride (18F-NaF) uptake is a marker of active vascular calcification associated with high-risk atherosclerotic plaque. OBJECTIVES: In patients with abdominal aortic aneurysm (AAA), the authors assessed whether 18F-NaF positron emission tomography (PET) and computed tomography (CT) predicts AAA growth and clinical outcomes. METHODS: In prospective case-control (n = 20 per group) and longitudinal cohort (n = 72) studies, patients with AAA (aortic diameter >40 mm) and control subjects (aortic diameter <30 mm) underwent abdominal ultrasound, 18F-NaF PET-CT, CT angiography, and calcium scoring. Clinical endpoints were aneurysm expansion and the composite of AAA repair or rupture. RESULTS: Fluorine-18-NaF uptake was increased in AAA compared with nonaneurysmal regions within the same aorta (p = 0.004) and aortas of control subjects (p = 0.023). Histology and micro-PET-CT demonstrated that 18F-NaF uptake localized to areas of aneurysm disease and active calcification. In 72 patients within the longitudinal cohort study (mean age 73 ± 7 years, 85% men, baseline aneurysm diameter 48.8 ± 7.7 mm), there were 19 aneurysm repairs (26.4%) and 3 ruptures (4.2%) after 510 ± 196 days. Aneurysms in the highest tertile of 18F-NaF uptake expanded 2.5× more rapidly than those in the lowest tertile (3.10 [interquartile range (IQR): 2.34 to 5.92 mm/year] vs. 1.24 [IQR: 0.52 to 2.92 mm/year]; p = 0.008) and were nearly 3× as likely to experience AAA repair or rupture (15.3% vs. 5.6%; log-rank p = 0.043). CONCLUSIONS: Fluorine-18-NaF PET-CT is a novel and promising approach to the identification of disease activity in patients with AAA and is an additive predictor of aneurysm growth and future clinical events. (Sodium Fluoride Imaging of Abdominal Aortic Aneurysms [SoFIA3]; NCT02229006; Magnetic Resonance Imaging [MRI] for Abdominal Aortic Aneurysms to Predict Rupture or Surgery: The MA3RS Trial; ISRCTN76413758).

Paget-Schroetter syndrome complicated by an incidental pulmonary embolism.

A young man presented with the severe right upper limb swelling following a heavy weight lifting that was thought to be caused by a biceps tendon rupture. However, subsequent investigations confirmed the diagnosis of Paget-Schroetter syndrome that was associated with an incidental pulmonary embolism. The patient underwent a successful thrombolysis followed by a surgical thoracic outlet decompression. Overall, the patient has made a good recovery.

An Investigation Into the Effects of In Vitro Dilution With Different Colloid Resuscitation Fluids on Clot Microstructure Formation.

BACKGROUND: Balancing the beneficial effects of resuscitation fluids against their detrimental effect on hemostasis is an important clinical issue. We aim to compare the in vitro effects of 3 different colloid resuscitation fluids (4.5% albumin, hydroxyethyl starch [Voluven 6%], and gelatin [Geloplasma]) on clot microstructure formation using a novel viscoelastic technique, the gel point. This novel hemorheologic technique measures the biophysical properties of the clot and provides an assessment of clot microstructure from its viscoelastic properties. Importantly, in contrast to many assays in routine clinical use, the measurement is performed using unadulterated whole blood in a near-patient setting and provides rapid assessment of coagulation. We hypothesized that different colloids will have a lesser or greater detrimental effect on clot microstructure formation when compared against each other. METHODS: Healthy volunteers were recruited into the study (n = 104), and a 20-mL sample of whole blood was obtained. Each volunteer was assigned to 1 of the 3 fluids, and the sample was diluted to 1 of 5 different dilutions (baseline, 10%, 20%, 40%, and 60%). The blood was tested using the gel point technique, which measures clot mechanical strength and quantifies clot microstructure (df) at the incipient stages of fibrin formation. RESULTS: df and clot mechanical strength decrease with progressive dilution for all 3 fluids. A significant reduction in df from baseline was recorded at dilutions of 20% for albumin (P < .0001), 40% for starch (P < .0001), and 60% for gelatin (P < .0001). We also observed significant differences, in terms of df, when comparing the different types of colloid (P < .0001). We found that albumin dilution produced the largest changes in clot microstructure, providing the lowest values of df (= 1.41 ± 0.061 at 60% dilution) compared with starch (1.52 ± 0.081) and gelatin (1.58 ± 0.063). CONCLUSIONS: We show that dilution with all 3 fluids has a significant effect on coagulation at even relatively low dilution volumes (20% and 40%). Furthermore, we quantify, using a novel viscoelastic technique, how the physiochemical properties of the 3 colloids exert individual changes on clot microstructure.

Intermittent foot claudication caused by a dynamic compression of the posterior tibial artery.

A young adult presented with an atypical intermittent foot claudication caused by a dynamic compression of the posterior tibial artery by a ganglion. This case highlights the diagnostic challenges when dealing with an entrapment syndrome. Subsequent open surgical treatment was successful, and the patient has made a good recovery.

Iatrogenic pseudoaneurysm of the peroneal artery.

An elderly patient who presented with an acute lower limb ischaemia was managed by thromboembolectomy: this led to revascularisation of the lower limb but resulted in an iatrogenic pseudoaneurysm of the peroneal artery. Subsequent endovascular treatment was successful, and the patient has made a good recovery.

An unusual radiological presentation of mucinous adenocarcinoma of the colon.

We report a case of an elderly patient presenting with the left iliac fossa mass. The provisional diagnosis included an inflammatory diverticular mass or sigmoid colon cancer. Interestingly, computed tomography (CT) of the abdomen and pelvis demonstrated the left incarcerated Spigelian hernia containing an inflamed loop of the colon with signs of an early strangulation. However, at operation, a mucinous tumor was found involving the descending and upper sigmoid colon. The tumor eroded through the anterior abdominal wall, which was excised "en bloc." In the presented case, CT findings suggestive of a benign etiology were misleading. This potentially could have had significant consequences if the patient was treated conservatively. This case highlights that clinical history and examination remain the core components of a safe surgical practice. Clinical judgment cannot be substituted even by the best quality imaging. Therefore, we feel that it is important to share our experience of the successful management of the presented case.

A gallbladder with the "hidden cystic duct": A brief overview of various surgical techniques of the Calot's triangle dissection.

We present a case of a middle-aged female who attended for a routine laparoscopic cholecystectomy as a day case surgery. At operation, she was found to have a distended gallbladder with an unusually prominent distal portion. This has made the dissection of the Calot's triangle challenging. As a result, the "critical view of safety" technique was applied. This allowed for the clear Calot's triangle visualization and identification of the cystic duct and artery. This case highlights that the knowledge of various ways of the cystic duct dissection is essential to every surgeon. Furthermore, this helps to adjust the dissection approach on an individual case bases ensuring avoidance of the common bile duct injuries.

Reverse intestinal rotation: a rare case of volvulus around a vitelline duct remnant.

We present a rare case of reverse intestinal rotation with volvulus around a Meckel's diverticulum attached to a vitelline duct remnant. The diagnosis was established by CT. The patient was treated with exploratory laparotomy and small bowel resection. The patient made a full recovery and was discharged home on the seventh postoperative day.

Successful reimplantation of the hypertrophied inferior mesenteric artery during an open abdominal aortic aneurysm repair.

Ischemic colitis is the most common form of an iatrogenic intestinal ischemia following an aortic surgery. It can be transient and self-limiting but, when severe, is associated with mortality even as high as 80%. Careful preoperative assessment can help to anticipate the need for the inferior mesenteric artery (IMA) reimplantation. Some patients lack the sufficient collateral blood supply to the colon and can benefit from the IMA reimplantation, which not only reduces the risk of postoperative colonic necrosis but also can be lifesaving. We report a case of a successful reimplantation of the IMA based on the careful preoperative planning. If unrecognized, this undoubtedly would lead to postoperative colonic ischemia. Therefore, we feel it is important to share our experience regarding the successful management of the presented case.

Rupture of the infrarenal abdominal aortic aneurysm (AAA) following an endovascular aneurysm repair (EVAR) due to an isolated type II endoleak.

We present a case of an elderly man with the persisting type II endoleak following endovascular aneurysm repair. In a view of the multiple comorbidities, the patient was denied an open elective repair. However, when presented with a ruptured aneurismal sac, he underwent an emergency open abdominal aortic aneurysm repair. Overall, the patient has made a good postoperative recovery.