Gadofosveset-enhanced thoracic MR venography: a comparative study evaluating steady state imaging versus conventional first-pass time-resolved dynamic imaging.

Background Dedicated blood-pool contrast agents combined with optimal angiographic protocols could improve the diagnostic accuracy of thoracic magnetic resonance angiography (MRA). Purpose To assess the clinical utility of Gadofesveset-enhanced imaging and compare an optimized steady-state (SS) sequence against conventional first-pass dynamic multi-phase (DMP) imaging. Material and Methods Twenty-nine patients (17 men, 12 women; mean age = 42.7, age range = 18-72 years) referred for MR thoracic venography were recruited. Imaging was performed on a 1.5T MRI system. A blood-pool contrast agent (Gadofesveset) was administered intravenously. Thirty temporal phases were acquired using DMP. This was immediately followed by a high-resolution SS sequence. Three radiologists in consensus reviewed seven thoracic vascular segments after randomizing the acquisition order. Image quality, stenoses, thromboses, and artifacts were graded using a categorical scoring system. The image quality for both approaches was compared using Wilcoxon's signed-rank test. McNemar's test was used to compare the proportions of stenosis grades, thrombus and artifacts. Results SS had significantly better image quality than DMP (3.14 ± 0.73 and 2.92 ± 0.60, respectively; P < 0.001). SS identified fewer stenoses (>50%) than DMP; the differences in stenosis categorizations was statistically significant ( P = 0.013). There was no significant difference in the proportions of vessels with thromboses ( P = 0.617). DMP produced more artifacts than SS (101 versus 85); however, the difference was not statistically significant ( P = 0.073). Conclusion Gadofesveset-enhanced thoracic angiography is clinically feasible. SS imaging produces better image quality and fewer artifacts than conventional DMP imaging.

Renal Autotransplantation for Uncontrolled Hypertension in Nonatherosclerotic Renal Artery Stenosis-2 Case Reports and a Brief Review of the Literature.

Fibromuscular dysplasia is the most common cause of renovascular hypertension in young adults under 40 years old. It is potentially amenable to renal artery angioplasty, which frequently normalizes blood pressure. However, limited options exist if angioplasty is not technically possible, or restenosis occurs. Here, we describe 2 patients who presented with hypertension secondary to renal artery stenosis. In the first case, a young adult with hypertension secondary to renal artery stenosis (fibromuscular dysplasia), developed restenosis 11 weeks after an initially successful renal artery angioplasty. In the second case, a patient with neurofibromatosis type 1 was diagnosed with hypertension secondary to renal artery stenosis. Angioplasty was not possible due to multiple branch occlusions. Both individuals went on to have successful renal autotransplantations, which ultimately cured their hypertension. In this article, we review the background, indications, and blood pressure outcomes in relation to renal autotransplantation in nonatherosclerotic renal artery stenosis.

Use of heparin coated vascular stents in femoropopliteal chronic total occlusions: Long term outcomes.

PURPOSE: To evaluate the long-term clinical efficacy of the Tigris © stent (Gore ©) in femoropopliteal chronic total occlusions (CTOs). MATERIAL AND METHODS: This single centre retrospective study included 29 patients treated with 47 Tigris© stents for CTOs. Lesion location, type, length, revascularisation method, smoking status and diabetes were reviewed. Clinical follow-up was performed. Primary safety points were complications and adverse events. Secondary efficacy points were symptom deterioration, freedom from target lesion revascularization (TLR) and amputation rate. Freedom from TLR was evaluated with Kaplan-Meier analysis; Cox multivariable logistic regression analysis of the factors associated with stent re-occlusion was also performed. RESULTS: All procedures were technically successful without any peri- or post-procedural complications and adverse events. Median follow-up was 48 months (range: 7-70). Lesions were located in the superficial femoral (19), popliteal (3) and femoropopliteal (7) arteries with mean lesion length 13.9 ±â€¯7.6 cm. In 12 patients subintimal recanalization was performed. Freedom from TLR rates at 6, 12, 18, 24 and 36 months were 96.6 %, 85.7 %, 81.9 %, 78.2 % and 74.3 % respectively. No stent fracture was observed and no amputation was performed in any of the patients. Smoking status, the presence of diabetes, lesion localization and recanalization type were not associated with stent re-occlusion. CONCLUSION: This study demonstrated that use of a heparin coated vascular stent for femoropopliteal CTOs appears to offer satisfactory long-term results.

Endovascular Repair of Superior Mesenteric Arteriovenous Fistula Causing Early Mesenteric Steal Syndrome Following Abdominal Gunshot Injury.

INTRODUCTION: Superior mesenteric arteriovenous fistulae (SMAVF) are rare, usually secondary to trauma or iatrogenic injury and typically present sometime after the initial insult. REPORT: A 30 year old male underwent immediate laparotomy for abdominal gunshot injury. The small bowel mesentery contained a large haematoma and a palpable thrill. CT demonstrated a large SMAVF. At re-look laparotomy, small bowel ischaemia was noted and following this endovascular SMA stent graft insertion was performed, with excellent angiographic and clinical results. CONCLUSION: The first report of immediate traumatic SMAVF leading to acute mesenteric steal syndrome and successful management with endovascular stent insertion is presented.

Ultrasound-assisted thrombolysis of an occluded transjugular portosystemic shunt.

Transjugular intrahepatic portosystemic shunt (TIPS) insertion is commonly performed for refractory ascites or variceal bleeding. However, TIPS dysfunction can be seen in both early and late settings, with shunt thrombosis a particular problem. Treatment of shunt dysfunction commonly involves angioplasty and re-lining, with or without embolectomy, mechanical thrombectomy, or thrombolysis. Ultrasound-assisted thrombolysis has been shown to be successful for treatment of pulmonary embolism, deep vein thrombosis, and peripheral arterial thromboembolism, but has not been described before for TIPS occlusion. Ultrasound is theorized to lead to a shortened duration of thrombolysis due to thinning of the fibrin clot and exposing plasminogen receptor sites. In this technical report, we describe the first published use of ultrasound-assisted thrombolysis in the declotting of an occluded TIPS. We found that the use of ultrasound-assisted thrombolysis allowed a relatively short duration of thrombolytic therapy, with removal of thrombus extending into the portal vein, facilitating stent re-lining. No complications were observed, in particular no bleeding complications. The TIPS remains patent at 8 months postprocedure.

Intraprocedural Distal Embolization After Femoropopliteal Angioplasty: Is There a Role for Below-the-Knee Stents?

PURPOSE: Intraprocedural distal embolization is an accepted complication of femoropopliteal angioplasty. The purpose of this study is to assess the use of below-the-knee stents in the "bail-out" of conventional methods. MATERIALS AND METHODS: We retrospectively reviewed 1485 of femoropopliteal angioplasties that were performed in our centre in a 4-year period and analysed 12 cases (<1%) where distal embolization that required further intervention occurred. In all cases lesions were chronic and 75% suffered from critical limb ischaemia. The target vessel was the SFA in all of the cases with a long (>10 cm) occlusion in 50%. A three-vessel run-off was present in only 25%. Patients that received a stent as a limb salvage attempt were analysed. Outcome measures were technical success, clinical success and procedure-related complications. Multivariate regression analysis of the factors related to stenting was also performed. RESULTS: In 41% of the cases with distal embolization, recanalization with aspiration, thrombolysis or angioplasty offered a satisfactory result. In 59%, conventional methods were ineffective; a stent was deployed in 85%, whereas in 15% surgical embolectomy was required. Technical and clinical success of the stent cases was 100% without any procedure-related complications. There was significance (p < 0.05) between critical limb ischaemia and stenting; single-vessel run-off has also shown a positive trend (p = 0.88). CONCLUSION: Stents appear as a valid salvage option for infragenicular distal embolization when conventional methods fail; the likelihood of having to use a stent is higher for patients with critical limb ischaemia and a single-vessel run-off.

A semi-automatic method for the extraction of the portal venous input function in quantitative dynamic contrast-enhanced CT of the liver.

OBJECTIVE: To aid the extraction of the portal venous input function (PVIF) from axial dynamic contrast-enhanced CT images of the liver, eliminating the need for full manual outlining of the vessel across time points. METHODS: A cohort of 20 patients undergoing perfusion CT imaging of the liver was examined. Dynamic images of the liver were reformatted into contiguous thin slices. A region of interest was defined within a transverse section of the portal vein on a single contrast-enhanced image. This region of interest was then computationally projected across all thin slices for all time points to yield a semi-automated PVIF curve. This was compared against the "gold-standard" PVIF curve obtained by conventional manual outlining. RESULTS: Bland-Altman plots of curve characteristics indicated no substantial difference between automated and manual PVIF curves [concordance correlation coefficient in the range (0.66, 0.98)]. No substantial differences were shown by Bland-Altman plots of derived pharmacokinetic parameters when a suitable kinetic model was applied in each case [concordance correlation coefficient in range (0.92, 0.95)]. CONCLUSION: This semi-automated method of extracting the PVIF performed equivalently to a "gold-standard" manual method for assessing liver function. Advances in knowledge: This technique provides a quick, simple and effective solution to the problems incurred by respiration motion and partial volume factors in the determination of the PVIF in liver dynamic contrast-enhanced CT.