Photon-Counting Detector CT Angiography for Endoleak Detection After Endovascular Aortic Repair: Triphasic CT With True Noncontrast Versus Biphasic CT With Virtual Noniodine Imaging

OBJECTIVES

The aim of this study was to compare image quality and endoleak detection after endovascular abdominal aortic aneurysm repair between a triphasic computed tomography (CT) with true noncontrast (TNC) and a biphasic CT with virtual noniodine (VNI) images on photon-counting detector CT (PCD-CT).

MATERIALS AND METHODS

Adult patients after endovascular abdominal aortic aneurysm repair who received a triphasic examination (TNC, arterial, venous phase) on a PCD-CT between August 2021 and July 2022 were retrospectively included. Endoleak detection was evaluated by 2 blinded radiologists on 2 different readout sets (triphasic CT with TNC-arterial-venous vs biphasic CT with VNI-arterial-venous). Virtual noniodine images were reconstructed from the venous phase. The radiologic report with additional confirmation by an expert reader served as reference standard for endoleak presence. Sensitivity, specificity, and interreader agreement (Krippendorf α) were calculated. Image noise was assessed subjectively in patients using a 5-point scale and objectively calculating the noise power spectrum in a phantom.

RESULTS

One hundred ten patients (7 women; age, 76 ± 8 years) with 41 endoleaks were included. Endoleak detection was comparable between both readout sets with a sensitivity and specificity of 0.95/0.84 (TNC) versus 0.95/0.86 (VNI) for reader 1 and 0.88/0.98 (TNC) versus 0.88/0.94 (VNI) for reader 2. Interreader agreement for endoleak detection was substantial (TNC: 0.716, VNI: 0.756). Subjective image noise was comparable between TNC and VNI (4; IQR [4, 5] vs 4; IQR [4, 5], P = 0.44). In the phantom, noise power spectrum peak spatial frequency was similar between TNC and VNI (both f peak = 0.16 mm -1 ). Objective image noise was higher in TNC (12.7 HU) as compared with VNI (11.5 HU).

CONCLUSIONS

Endoleak detection and image quality were comparable using VNI images in biphasic CT as compared with TNC images in triphasic CT offering the possibility to reduce scan phases and radiation exposure.

Determinants of Advanced Liver Fibrosis in Adult Patients After Fontan Palliation: Usefulness of Ultrasound Transient Elastography

BACKGROUND

Fontan-associated liver disease is an increasing concern. Our aim was to assess prevalence and predictors of advanced liver fibrosis with a specific focus on utility of liver stiffness measurement by ultrasound transient elastography.

METHODS

A total of 97 adult Fontan patients (55% male, median age: 23.1 years, interquartile range [IQR]: 18.7-30.6); 92 (95%) were evaluated with transient elastography, and 50 (52%) underwent transjugular liver biopsy. Advanced liver fibrosis was defined as congestive hepatic fibrosis score 3 or 4.

RESULTS

Only 4 patients (4%) had liver stiffness values < 10 kilopascal (kPa). Liver-stiffness measurements correlated weakly with peak oxygen uptake on exercise testing and Fontan pressure but not with Model for End-Stage Liver Disease excluding INR (MELD-XI) score or spleen size. Serial follow-up liver stiffness measurements in 73 clinically stable patients showed large variability among individual patients. Advanced liver fibrosis was present in 35 of 50 (70%) patients on liver biopsy and was associated to MELD-XI-Score ≥ 11 and splenomegaly but not to liver-stiffness measurements. Advanced liver fibrosis was not associated with patient age or time since Fontan operation but with younger age at completion of Fontan (3.7 years, IQR: 2.3-6.3 vs 6.8 years; IQR: 3.5-12.1; P = 0.037).

CONCLUSIONS

In our cohort, advanced liver fibrosis was present in the majority of adult Fontan patients. Liver stiffness as measured by transient elastography was not associated with the degree of liver fibrosis. Because of its high variability on serial measurements, it seems not to be useful for clinical decision making. The unexpected finding that younger age at completion of Fontan was associated with advanced liver fibrosis merits further evaluation.

Long-term patency of arteriovenous fistulas for hemodialysis: A decade's experience in a transplant unit

BACKGROUND

The heterogeneous quality of studies on arteriovenous fistulas outcome, with variable clinical settings and large variations in definitions of patency and failure rates, leads to frequent misinterpretations and overestimation of arteriovenous fistula patency. Hence, this study aimed to provide realistic and clinically relevant long-term arteriovenous fistula outcomes.

METHODS

We retrospectively analyzed all autologous arteriovenous fistulas at our center over a 10-year period (2012-2022). Primary and secondary patency analysis was conducted using the Kaplan-Meier method; multivariate analysis of variance was used to detect outcome predictors. Vascular access-specific endpoints were defined according to the European guidelines on vascular access formation.

FINDINGS

Of 312 arteriovenous fistulas, 57.5% (n = 181) were radio-cephalic (RC_AVF), 35.2% (n = 111) brachio-cephalic (BC_AVF), and 6.3% (n = 20) brachio-basilic (BB_AVF). 6, 12, and 24 months follow-up was available in 290 (92.1%), 282 (89.5%), and 259 (82.2%) patients, respectively. Primary patency rates at 6, 12, and 24 months were 39.5%, 34.8%, and 27.2% for RC_AVF, 58.3%, 44.4%, and 27.8% for BC_AVF, and 40.0%, 42.1%, and 22.2% for BB_AVF (p = 0.15). Secondary patency rates at 6, 12, and 24 months were 65.7%, 63.8%, and 59.0% for RC_AVF, 77.7%, 72.0%, and 59.6% for BC_AVF, and 65.0%, 68.4%, and 61.1% for BB_AVF (p = 0.29). Factors associated with lower primary and secondary patency were hemodialysis at time of arteriovenous fistula formation (p = 0.037 and p = 0.024, respectively) and higher Charlson Comorbidity Index (p = 0.036 and p < 0.001, respectively). Previous kidney transplant showed inferior primary patency (p = 0.005); higher age inferior secondary patency (p < 0.001).

DISCUSSION

Vascular access care remains challenging and salvage interventions are often needed to achieve maturation or maintain patency. Strict adherence to standardized outcome reporting in vascular access surgery paints a more realistic picture of arteriovenous fistula patency and enables reliable intercenter comparison.

Prediction of treatment response to transarterial radioembolization of liver metastases: Radiomics analysis of pre-treatment cone-beam CT: A proof of concept study

Purpose

To investigate the potential of texture analysis and machine learning to predict treatment response to transarterial radioembolization (TARE) on pre-interventional cone-beam computed tomography (CBCT) images in patients with liver metastases.

Materials and Methods

In this IRB-approved retrospective single-center study 36 patients with a total of 104 liver metastases (56 % male, mean age 61.1 ± 13 years) underwent CBCT prior to TARE and follow-up imaging 6 months after therapy. Treatment response was evaluated according to RECIST version 1.1 and dichotomized into disease control (partial response/stable disease) versus disease progression (progressive disease). After target lesion segmentation, 104 radiomics features corresponding to seven different feature classes were extracted with the pyRadiomics package. After dimension reduction machine learning classifications were performed on a custom artificial neural network (ANN). Ten-fold cross validation on a previously unseen test data set was performed.

Results

The average administered cumulative activity from TARE was 1.6 Gbq (± 0.5 Gbq). At a mean follow-up of 5.9 ± 0.8 months disease control was achieved in 82 % of metastases. After dimension reduction, 15 of 104 (15 %) texture analysis features remained for further analysis. On a previously unseen set of liver metastases the Multilayer Perceptron ANN yielded a sensitivity of 94.2 %, specificity of 67.7 % and an area-under-the receiver operating characteristics curve of 0.85.

Conclusion

Our study indicates that texture analysis-based machine learning may has potential to predict treatment response to TARE using pre-treatment CBCT images of patients with liver metastases with high accuracy.

Recanalization of Chronic Noncirrhotic, Nonmalignant Splanchnic Thromboses is Feasible: A Transsplenic Assisted Patient-Tailored Approach

The purpose of this study was to evaluate the feasibility of recanalization of chronic noncirrhotic, nonmalignant splanchnic thromboses with a transsplenic assisted patient-tailored approach with or without transjugular intrahepatic portosystemic shunt (TIPS) creation. In this retrospective study, 10 patients (median age, 48.4 years; interquartile range, 5.1 years) underwent revascularization between November 2016 and August 2020. Portal cavernoma was present in all patients, with complete splenic vein thrombosis in 70%. The technical success rate was 80%. Additional TIPS creation was performed in 5 (50%) patients. At a median follow-up of 19.3 months (interquartile range, 17.9 months), the primary and secondary patency rate was 70% and 100%, respectively. During follow-up, 1 patient died due to recurrent upper gastrointestinal variceal hemorrhage. In conclusion, percutaneous transsplenic assisted recanalization of chronic noncirrhotic, nonmalignant splanchnic thromboses is feasible. However, multiple access points may still be needed. Additional TIPS creation appears to be necessary only in case of insufficient portal venous flow into the liver.

Fusion of Preinterventional MR Imaging With Liver Perfusion CT After RFA of Hepatocellular Carcinoma: Early Quantitative Prediction of Local Recurrence

OBJECTIVES

The aim of this study was to evaluate the ability of fusion of pretreatment magnetic resonance (MR) imaging with posttreatment perfusion-CT (P-CT) after radiofrequency ablation (RFA) of hepatocellular carcinomas (HCCs) and to determine treatment success in an objective, quantitative way.

MATERIALS AND METHODS

In this institutional review board-approved study, 39 patients (78.4% male; mean age 68.2 ± 8.5 years) with a total of 43 HCCs, who underwent RFA at our institution and had diagnostic pre-RFA MR imaging and post-RFA P-CT, were included in the study. Post-RFA P-CT was performed within 24 hours after RFA. In a first step, the pre-RFA MR imaging, depicting the HCC, was registered onto the post-RFA P-CT using nonrigid image registration. After image registration, the MR data were reloaded jointly with the calculated perfusion parameter volumes into the perfusion application for quantitative analysis. A 3-dimensional volume of interest was drawn around the HCC and the ablation zone; both outlines were automatically projected onto all perfusion maps. Resulting perfusion values (normalized peak enhancement [NPE, %]; arterial liver perfusion [ALP, in mL/min/100 mL]; BF [blood flow, mL/100 mL/min]; and blood volume [BV, mL/100 mL]) and histogram data were recorded. Local tumor recurrence was defined in follow-up imaging according to the EASL guidelines.

RESULTS

Image registration of MR imaging and CT data was successful in 37 patients (94.9%). Local tumor recurrence was observed in 5 HCCs (12%). In the local tumor recurrence group (LTR-group), HCC size was significantly larger (22.7 ± 3.9 cm vs 17.8 ± 5.3 cm, P = 0.035) and the ablation zone was significantly smaller (29.8 ± 6.9 cm vs 39.3 ± 6.8 cm, P = 0.014) compared with the no-local tumor recurrence group (no-LTR group). The differences (ablation zone - tumor) of the perfusion parameters NPE, ALP, BF, and BV significantly differed between the 2 groups (all P's < 0.005). Especially, the difference (ablation zone - tumor) of NPE and ALP, with a cutoff value of zero, accurately differentiated between LTR or no-LTR in all cases. A negative difference of these perfusion parameters identified local tumor recurrence in all cases.

CONCLUSIONS

Image registration of pre-RFA MR imaging onto post-RFA P-CT is feasible and allows to predict local tumor recurrence within 24 hours after RFA in an objective, quantitative manner and with excellent accuracy.

Lymphovenous Anastomosis for the Treatment of Thoracic Duct Lesion: A Case Report and Systematic Review of Literature

BACKGROUND

Chylous leak is an uncommon complication after head and neck surgery and typically results from a lesion of the thoracic duct (TD). Beside conservative treatment, different minimally invasive and surgical procedures exist, of which almost all lead to a total closure of the TD.

METHODS

We report on a rare case of microsurgical lymphovenous anastomosis to treat a TD lesion. An additional systematic review on surgical procedures to treat TD lesions with special attention to lymphovenous anastomoses was performed according to the PRISMA guidelines.

RESULTS

A 52-year-old patient with a chylous fistula after modified radical neck dissection was successfully treated by a lymphovenous anastomosis of the TD and external jugular vein with additional coverage by sternocleidomastoid muscle flap. The patient showed a complete resolution of chylous leak with an uneventful postoperative course.The systematic search of literature yielded 684 articles with 4 case reports on lymphovenous anastomosis in chylous leak with a high success rate. Other surgical techniques include transcervical, thoracoscopic, or video-assisted thoracoscopic TD ligation, either alone or combined with a local muscle flap.

CONCLUSIONS

Lymphovenous anastomosis of the TD is a feasible and safe technique allowing for treatment of cervical TD lesions, especially if minimally invasive procedures fail. Compared with other techniques, lymphatic circulation can successfully be maintained.

Frequency and causes of delayed diagnosis of visceral artery pseudoaneurysms with CT: Lessons learned

Objective

Visceral artery pseudoaneurysms (VAPA) are associated with a high morbidity and mortality, but sometimes are missed in initial computed tomography (CT) examinations. The aims of this study were to determine the frequency and causes of misdiagnoses of VAPA with CT.

Materials and Methods

We retrospectively identified 77 patients with VAPA in our database who underwent contrast-enhanced CT. The frequency of delayed diagnosis was determined and the reasons were noted. We identified the etiology of VAPA, measured size, and noted the affected vessels.

Results

Forty-five of the 77 patients (58 %) had a delayed diagnosis of VAPA. There was no difference in the rate of missed VAPA in symptomatic compared to asymptomatic patients (p = 0.255). The majority of VAPA were associated with previous surgery or interventions (n = 48/62 %). The major affected vessel was the hepatic (n = 31) followed by the splenic artery (n = 17). The main reasons for misdiagnosis were a missed arterial phase in CT (n = 16/36 %), artifacts masking the aneurysm (n = 9/20 %), overlooked pseudoaneurysm (n = 19/42 %), and misinterpretation by attending radiologists (n = 1/2 %). Missed VAPA were smaller (median 8 mm) than those VAPA that were initially diagnosed (median 13 mm, p < 0.01), but occurred with a similar frequency in larger and smaller visceral arteries (p = 0.601).

Conclusions

Our study showed that 58 % of VAPA were diagnosed with delay, with the following four reasons for misdiagnosis: Lack of an arterial contrast phase in CT, no techniques for artifact reduction, and lack of awareness of the radiologists. Avoiding delayed diagnosis will most probably improve outcome of patients with VAPA.

Improved technique for sheath supported contralateral limb gate cannulation in endovascular abdominal aortic aneurysm repair

Background: To present a technique of sheath supported contralateral limb gate (CLG) cannulation of modular bifurcated stent-graft in endovascular abdominal aortic repair. Materials and methods: After totally percutaneous bilateral femoral access, the 9F introducer sheath is exchanged to a 30 cm 12 fr introducer sheath over a stiff wire contralateral to the intended main stent-graft insertion side and advanced into the aorta below the lowest renal artery. Parallel to the stiff wire within the sheath an additional standard J-tip guidewire with a 5 fr Pigtail angiographic catheter is advanced to the level of the renal arteries. After main body deployment, the 12 fr introducer sheath and J-tip wire with pigtail catheter are retracted until the CLG opening level, maintaining the stiff "buddy" wire in position to support the 12 fr sheath, maintaining its distal opening close to the contralateral gate opening to achieve easy cannulation. Results: Retrospective analysis of video archive from July 2016 to February 2018 evidenced 55 recorded EVAR cases. All CLG cannulations were obtained with Standard J-tip or Terumo Glidewire wires and with Pig-Tail or Berenstein catheters. Technical success was 100 %. Mean fluoroscopy time to accomplish CLG cannulation was 37.6 33 (range 1-105) seconds. The aortic carrefour angulation on coronal axis strongly correlates with cannulation time p = <.001, with longer cannulation time for higher carrefour angulations on coronal axis (Pearson correlation coefficient 0.47). Conclusions: The use of 12 fr sheath with parallel wire introduction technique, appears to be a safe and reliable tool to facilitate CLG cannulation during EVAR procedures.

Primary Endovascular Elective Repair and Repair of Ruptured Isolated Iliac Artery Aneurysms Is Durable-Results of 72 Consecutive Patients

PURPOSE

To evaluate outcome of endovascular elective repair and repair of ruptured isolated iliac artery aneurysms (IIAAs) as a primary treatment strategy.

MATERIALS AND METHODS

All patients with an IIAA undergoing endovascular treatment were included. Aneurysms were classified according to an anatomic classification and treated with coiling of the internal iliac artery, stent graft placement in the common to external iliac artery, or placement of a bifurcated aortoiliac stent graft. Between November 1996 and November 2015, 72 patients with 85 IIAAs underwent endovascular repair. Mean age was 73.9 years ± 9.2. Common iliac artery was involved in 63 patients (74.1%), internal iliac artery was involved in 21 patients (24.7%), and external iliac artery was involved in 1 patient (1.2%). Mean diameter was 5 cm (range, 2.5-11 cm). Emergency repair was performed in 19 patients owing to rupture (26.4%).

RESULTS

Overall primary technical success rate was 95.8% with conversion rate to open surgery of 4.2% (all in the emergency group) and in-hospital mortality rate of 1.4%. During mean follow-up of 4.3 years ± 3.3 (median 3.8 y; range, 0-14.2 y), 17 endoleaks were observed (6 type I, 10 type II, 1 type IIIa). Overall reintervention rate was 16.7%. Primary patency rate was 98.6%. During the follow-up period, 22 deaths occurred (30.6%), including 2 aneurysm-related deaths (2.8%).

CONCLUSIONS

Primary endovascular repair of IIAAs shows excellent results and should be considered as first-line therapy. Surgical backup should be available in emergency cases.

Early outcomes with a single-sided access endovascular stent

OBJECTIVE

The objective of this study was to report the 1-year follow-up study results of the new Horizon stent graft (Endospan, Herzliya, Israel) from two different prospective consecutive trials. The Horizon abdominal aortic aneurysm stent graft system is a 14F profile system requiring only a single access site. It consists of three modules, introduced separately: base limb (iliac to iliac limb); distal aortic limb; and proximal aortic limb with a bare suprarenal crown and active fixation.

METHODS

Data from the first in man (FIM) clinical study with 10 patients enrolled and the pivotal study with 30 patients were analyzed. Outcomes measured were freedom from major adverse events (MAEs) including all-cause mortality, myocardial infarction, renal failure, respiratory failure, paraplegia, stroke, bowel ischemia, and procedural blood loss ≥1000 mL. Performance end points included successful delivery and deployment of the device, freedom from aneurysm growth ≥5 mm, type I or type III endoleak, stent graft occlusion, conversion to open surgery, rupture, and stent graft migration.

RESULTS

In the FIM study, one conversion to open surgery with >1000 mL of blood loss was registered perioperatively. In the pivotal study, no perioperative MAE was registered. Overall, at 1-year follow-up, two deaths and one aneurysm growth unrelated to endoleak were registered.

CONCLUSIONS

The results of both the FIM and pivotal studies demonstrated that 39 of 40 procedures were successful for delivery and deployment of the Horizon stent graft. No MAE was registered during the follow-up. The primary safety and performance end points were met in both studies.

Ultrasound Needle Visibility in Contrast Mode Imaging: An In Vitro and Ex Vivo Study

Purpose To evaluate needle visibility in ultrasound under contrast mode conditions.

Materials and Methods Needle visibility was evaluated for bevel, EchoTip® and shaft of 18G Chiba biopsy needle with a 9 MHz linear probe (GE Logiq E9). Insertion angles varied between 30°(steep) and 90°(parallel to the probe surface). The acoustic output varied from 5–28%. 2 different contrast mode presets with either 'Amplitude Modulation' (Penetration) or 'Phase Inversion Harmonics' (High Resolution) were assessed. All other imaging parameters were kept constant. The visibility of bevel, EchoTip® and shaft was assessed for grayscale and color-coded images with a 3-point Likert-like scale (not, poorly, well visible) by 2 independent readers. The echogenicity of the needle bevel, EchoTip® and shaft was assessed in deciBel (dB) on the color-coded images.

Results With the parallel insertion angle, all needle areas were well visible. With steep insertion the EchoTip® was the only visible area. High Resolution was superior to Penetration (p<0.001). The visibility and echogenicity of the needle bevel (r grayscale=0.109, pgrayscale=0.178; r color-coded=0.236, pcolor-coded=0.266; r dB=0.956, pdB=0.001), EchoTip® (r grayscale+= 0.477, pgrayscale+= 0.018; r color-coded=0.540, pcolor-coded+= 0.006; r dB=0.911, pdB=0.001) and shaft (r grayscale=0.124, pgrayscale=0.563; r color-coded=0.061, pcolor-coded+= 0.775; r dB+= 0.926, pdB=0.001) increased with increasing acoustic output. Grayscale images were superior to color-coded images for needle visibility (p=0.004).

Conclusion Parallel needle insertion, use of an echogenic tip, adequate choice of presets, increased acoustic output, and dual view of grayscale and color-coded images improve needle visibility in ultrasound under contrast mode conditions.

Predilation technique with balloon angioplasty to facilitate percutaneous groin access of large size sheath through scar tissue

Purpose

Percutaneous remote access for endovascular aortic repair is an advantageous alternative to open access. Previous surgery in the femoral region and the presence of synthetic vascular grafts in the femoral/iliac arteries represent major limitations to percutaneous remote access. The aim of this study was to evaluate an original technique used for enabling percutaneous remote access for thoracic or abdominal endovascular aortic repair in patients with scar tissue and/or a vascular graft in the groin.

Methods

Twenty-five consecutive patients with a thoracic (11/25; 44%) or an aortic aneurysm (14/25; 66%) and with a synthetic vascular graft in the groin (16/25; 64%) or a redo groin access (9/25; 36%) were managed through the percutaneous remote access. In all patients, a percutaneous transluminal angioplasty balloon was used to predilate the scar tissue and the femoral artery or the synthetic vascular graft after preclosing (ProGlide®; Abbott Vascular, Santa Clara, CA, USA). In 10 patients, requiring a 20 Fr sheath, a 6 mm percutaneous transluminal angioplasty balloon was used; and in the remaining 15, requiring a 24 Fr sheath, an 8 mm percutaneous transluminal angioplasty balloon. Preclosing was exclusively performed using ProGlide®. Mean follow-up was 15 months.

Results

In all cases, stent-graft deployment was successful. There was one surgical conversion (4%; 1/25) due to bleeding from a femoral anastomosis. Two cases required additional percutaneous maneuvers (postclosing with another system in one patient and endoluminal shielding with stent-graft in the other patient). No pseudoaneurysm or access complication occurred during the follow-up.

Conclusions

Percutaneous access in redo groins with scar tissue and/or synthetic vascular graft using ultrasound-guided punction, preclosing with ProGlide® system and predilation with percutaneous transluminal angioplasty balloon to introduce large size sheath as used for endovascular aortic repair showed to be feasible, safe and with few local complications.

CT Perfusion for Early Response Evaluation of Radiofrequency Ablation of Focal Liver Lesions: First Experience

PURPOSE

To investigate the value of perfusion CT (P-CT) for early assessment of treatment response in patients undergoing radiofrequency ablation (RFA) of focal liver lesions.

METHODS AND MATERIALS

20 consecutive patients (14 men; mean age 64 ± 14) undergoing P-CT within 24 h after RFA of liver metastases (n = 10) or HCC (n = 10) were retrospectively included. Two readers determined arterial liver perfusion (ALP, mL/min/100 mL), portal liver perfusion (PLP, mL/min/100 mL), and hepatic perfusion index (HPI, %) in all post-RFA lesions by placing a volume of interest in the necrotic central (CZ), the transition (TZ), and the surrounding parenchymal (PZ) zone. Patients were classified into complete responders (no residual tumor) and incomplete responders (residual/progressive tumor) using imaging follow-up with contrast-enhanced CT or MRI after a mean of 57 ± 30 days. Prediction of treatment response was evaluated using the area under the curve (AUC) from receiver operating characteristic analysis.

RESULTS

Mean ALP/PLP/HPI of both readers were 4.8/15.4/61.2 for the CZ, 9.9/16.8/66.3 for the TZ and 20.7/29.0/61.8 for the PZ. Interreader agreement of HPI was fair for the CZ (intraclass coefficient 0.713), good for the TZ (0.813), and excellent for the PZ (0.920). For both readers, there were significant differences in HPI of the CZ and TZ between responders and nonresponders (both, P < 0.05). HPI of the TZ showed the highest AUC (0.911) for prediction of residual tumor, suggesting a cut-off value of 76 %.

CONCLUSION

Increased HPI of the transition zone assessed with P-CT after RFA might serve as an early quantitative biomarker for residual tumor in patients with focal liver lesions.

Long-term results of simplified frozen elephant trunk technique in complicated acute type A aortic dissection: A case–control study

Aim

To describe the long-term experience of a simplified frozen elephant trunk technique (sFETT) used in complicated acute type A aortic dissection (AAAD) treatment.

Methods and results

Between January 2001 and December 2012, 34 patients (mean age 59.9 ± 11.0 years) with complicated AAAD (DeBakey I) underwent an emergency surgery including sFETT. sFETT consisted in gluing the dissected aortic arch wall layers with gelatine-resorcinol adhesive and video-assisted antegrade open arch aortic stent-graft deployment in the arch or proximal descending aorta. In addition to sFETT, the aortic root was addressed with standard techniques. A 30-day mortality was 14.7% (five patients) due to bleeding (1), multiple organ failure (2), and colon ischemia (2). Postoperative morbidity included neurological (2), renal (1) and cardio-pulmonary complications (4), as well as wound infection (1). Mean follow-up was 74.4 ± 45.0 months. Actual survival rates were 73.5% at 1 year, 70.2% at 5 years, and 58.5% at 13 years of follow-up. Six patients died during long-term follow-up from heart failure (1) and unknown reasons (5). Five patients required reoperation for aortic arch (3) or aorto-iliac (2) progression of aneurysm during the mid- and long-term follow-up. The remaining patients showed favorable evolution of the dissected aorta with false lumen occlusion in most cases and stable aortic diameters.

Conclusions

In AAAD patients, sFETT as used in our series is an easy and safe technique to repair the aortic arch. Long-term results after sFETT showed false lumen occlusion and stable aortic diameter in up to 13 years of follow-up.

Central venous catheter misplaced in the vertebral artery

KEY MESSAGE

Based on two cases presented and our recently published experience, we think that for the majority of patients with central venous catheters misplaced in the vertebral artery, stent graft placement is the best bailout option.

Arterial Therapies of Non-Colorectal Liver Metastases

BACKGROUND

The unique situation of the liver with arterial and venous blood supply and the dependency of the tumor on the arterial blood flow make this organ an ideal target for intrahepatic catheter-based therapies. Main forms of treatment are classical bland embolization (TAE) cutting the blood flow to the tumors, chemoembolization (TACE) inducing high chemotherapy concentration in tumors, and radioembolization (TARE) without embolizing effect but very high local radiation. These different forms of therapies are used in different centers with different protocols. This overview summarizes the different forms of treatment, their indications and protocols, possible side effects, and available data in patients with non-colorectal liver tumors.

METHODS

A research in PubMed was performed. Mainly clinical controlled trials were reviewed. The search terms were 'embolization liver', 'TAE', 'chemoembolization liver', 'TACE', 'radioembolization liver', and 'TARE' as well as 'chemosaturation' and 'TACP' in the indications 'breast cancer', 'neuroendocrine', and 'melanoma'. All reported studies were analyzed for impact and reported according to their clinical relevance.

RESULTS

The main search criteria revealed the following results: 'embolization liver + breast cancer', 122 results, subgroup clinical trials 16; 'chemoembolization liver + breast cancer', 62 results, subgroup clinical trials 11; 'radioembolization liver + breast cancer', 37 results, subgroup clinical trials 3; 'embolization liver + neuroendocrine', 283 results, subgroup clinical trials 20; 'chemoembolization liver + neuroendocrine', 202 results, subgroup clinical trials 9; 'radioembolization liver + neuroendocrine', 64 results, subgroup clinical trials 9; 'embolization liver + melanoma', 79 results, subgroup clinical trials 15; 'chemoembolization liver + melanoma', 60 results, subgroup clinical trials 14; 'radioembolization liver + melanoma', 18 results, subgroup clinical trials 3. The term 'chemosaturation liver' was tested without indication since only few publications exist and provided us with five results and only one clinical trial.

CONCLUSION

Despite many years of clinical use and documented efficacy on intra-arterial treatments of the liver, there are still only a few prospective multicenter trials with many different protocols. To guarantee the future use of these efficacious therapies, especially in the light of many systemic or surgical therapies in the treatment of non-colorectal liver metastases, further large randomized trials and transparent guidelines need to be established.

A 12-Year Experience With Chimney and Periscope Grafts for Treatment of Type I Endoleaks

Purpose: To evaluate the midterm outcomes of chimney and/or periscope grafts (CPGs) in patients presenting type I endoleak after a previous endovascular aneurysm repair (EVAR). Methods: Between June 2002 and April 2014, 24 consecutive patients (mean age 73.9±9.2 years; 23 men) presenting a type I endoleak were addressed with CPGs to extend the proximal and/or distal landing zone and to maintain side branch perfusion. Indication for treatment was a type Ia endoleak in 23 (96%) patients and a type Ib endoleak in one. Median interval from the previous EVAR to endoleak treatment with CPGs was 52.2±48.9 months (range 0.2–179). All patients had proximal/distal landing zones precluding any standard endovascular reintervention. Measured outcomes included technical success and perioperative mortality and morbidity. Technical success was defined as a procedure completed as intended, with no secondary procedures within 30 days. Midterm outcomes included survival, CPG patency, endoleaks, and freedom from reintervention. Results: Technical success was 96%; a single patient required an additional procedure to seal a recurrent type Ia endoleak. Intraoperative revascularization of all 55 target vessels (2.3/patient) with CPGs was successful. One (4%) patient died within 30 days. Estimated survival at 12, 24, and 36 months was 83%; estimated CPG patency at the same intervals was 94%. Over a mean follow-up of 23.4±29 months, 6 (25%) reinterventions were performed; of these, 4 were secondary to type I endoleak. Aneurysm diameters reduced from 88.3±26 to 85.5±33 mm (p=0.49) over the mean follow-up. Conclusion: The CPG technique is a safe and effective tool for treatment of type I endoleak after previous EVAR. The CPG technique is feasible even in nonelective patients, with excellent outcomes in terms of patency. Close imaging follow-up is warranted to rule out recurrent or de novo endoleaks.

Diagnostic performance of 18F-FDG-PET/CT in vascular graft infections

OBJECTIVE

The aim of this study was to evaluate the diagnostic accuracy of positron emission tomography/computed tomography with (18)F-fludeoxyglucose (FDG-PET/CT) in a population with suspected graft infection and to validate a new diagnostic imaging score for FDG-PET/CT.

METHODS

This was a prospective cohort study. FDG-PET/CT was performed prospectively in 34 patients with suspected graft infection, in 12 of them before the start of antimicrobial treatment. Diagnostic accuracy was assessed using a new five point visual grading score and by using a binary score. Maximum standardized uptake values (SUVmax) were calculated for quantitative measurements of metabolic activity, and cut off points were calculated using the receiver operator curve (ROC). The standard of reference was a microbiological culture, obtained after open biopsy or graft explantation.

RESULTS

Using the new scale, FDG-PET/CT correctly recognized 27 patients with graft infection, one patient was diagnosed as false positive, six patients were correctly classified as true negative, and no patients were rated false negative. Hence, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy of FDG-PET/CT for the diagnosis of graft infections were 100%, 86%, 96%, 100%, and 97%, respectively. Using a previously established binary score, sensitivity, specificity, PPV, NPV, and accuracy were 96%, 86%, 96%, 86%, and 94% respectively. ROC analysis suggested an SUVmax cut off value of ≥3.8 to differentiate between infected and non-infected grafts (p < .001). Additionally, FDG-PET/CT provided a conclusive clinical diagnosis in six of seven patients without graft infection (i.e., other sites of infections).

CONCLUSIONS

The diagnostic accuracy of FDG-PET/CT in the detection of aortic graft infection is high. A newly introduced five point visual grading score and early imaging prior to antimicrobial treatment may further improve the diagnostic accuracy.

Cardiac CT and echocardiographic evaluation of peri-device flow after percutaneous left atrial appendage closure using the AMPLATZER cardiac plug device

OBJECTIVES

The aim of the study was to examine frequency, size, and localization of peri-device leaks after percutaneous left atrial appendage (LAA)-closure with the AMPLATZER-Cardiac-Plug (ACP) by using a multimodal imaging approach, i.e. combined cardiac-CT and TEE follow-up.

BACKGROUND

Catheter-based LAA-occlusion using ACP aims to reduce the risk of stroke in patients with atrial fibrillation. Detection of peri-device leaks after ACP implantation by TEE is challenging, the few available data are inconsistent and the frequency of LAA leaks after ACP implantation remains therefore unclear.

METHODS

Cardiac-CT using a multi-phase protocol and a second-generation dual-source-CT-system was performed in 24 patients with non-valvular atrial fibrillation starting 3 months after LAA-closure by ACP. Color Doppler multiplane TEE was used to evaluate peri-device flow.

RESULTS

Cardiac-CT follow-up detected any persistent LAA contrast filling in 62% of patients (n = 15), but leak-sizes were small (1.5 ± 1.4 mm). Peri-device leaks were almost exclusively localized at the posterior portion of the LAA-orifice (>90%). TEE follow-up revealed peri-device flow in 36% of patients (jet-sizes: ≤ 4 mm). ACP-lobe compression (>10%) and perpendicular ACP-lobe orientation to the LAA-neck axis, that was also dependent on LAA anatomy, were substantially more frequent in patients with complete LAA closure.

CONCLUSION

The present study evaluates for the first time peri-device flow after LAA closure by ACP using a combined cardiac-CT and TEE follow-up. Persistent LAA-perfusion was frequently detected, leak-sizes were small and were less frequent when lobe compression was >10% and lobe orientation was perpendicular to the LAA-neck axis, that was also related to the LAA anatomy. The clinical significance of these small leaks after LAA-closure using ACP needs to be further evaluated in future studies.

Correspondence of high-frequency ultrasound and histomorphometry of healing rabbit Achilles tendon tissue

OBJECTIVES

Static and dynamic high-frequency ultrasound of healing rabbit Achilles tendons were set in relationship to histomorphometric analyses at three and six weeks post-surgery.

MATERIALS AND METHODS

Twelve New Zealand White rabbits received a clean-cut Achilles tendon laceration (the medial and lateral Musculus gastrocnemius) and were repaired with a four-strand Becker suture. Six rabbits got additionally a tight polyester urethane tube at the repair site in order to vary the adhesion extent. Tendons were analysed by static and dynamic ultrasound (control: healthy contralateral legs). The ultrasound outcome was corresponded to the tendon shape, tenocyte and tenoblast density, tenocyte and tenoblast nuclei width, collagen fibre orientation and adhesion extent.

RESULTS

The spindle-like morphology of healing tendons (ultrasound) was confirmed by the swollen epitenon (histology). Prediction of adhesion formation by dynamic ultrasound assessment was confirmed by histology (contact region to surrounding tissue). Hyperechogenic areas corresponded to acellular zones with aligned fibres and hypoechogenic zones to not yet oriented fibres and to cell-rich areas.

CONCLUSIONS

These findings add new in-depth structural knowledge to the established non-invasive analytical tool, ultrasound.

Stent-graft repairs of visceral and renal artery aneurysms are effective and result in long-term patency

PURPOSE

To report on the long-term outcomes of endovascular exclusion of visceral and renal artery aneurysms with the use of stent-grafts.

MATERIALS AND METHODS

Nineteen consecutive patients (mean age, 59 y ± 16 [standard deviation]) with a total of 19 visceral artery aneurysms (VAAs; hepatic, n = 6; celiac, n = 4; renal, n = 4; splenic, n = 3; and superior mesenteric, n = 2) were electively (n = 9) or emergently (n = 10) treated with a variety of stent-grafts. The etiology of aneurysms was variable: postoperative (n = 9), infectious (n = 3), idiopathic (n = 4), Ehlers-Danlos syndrome (n = 2), and α1-antitrypsin deficiency (n = 1). The patients were followed up with clinical examinations and computed tomographic (CT) angiography.

RESULTS

No patient was lost to follow-up. The in-hospital mortality rate was 11% (n = 2). Three patients died of cancer after successful VAA treatment. At the last follow-up, the remaining 14 patients were alive and well. Three patients refused follow-up CT angiography. CT angiography demonstrated stent-graft patency at a mean follow-up of 28 months (range, 2-100 mo) in nine of 11 remaining patients (82%) and thrombosis in two patients (one with a splenic and one with a renal artery stent-graft). These events were asymptomatic. All aneurysms decreased in size. Late repeat intervention was performed to treat a celiac restenosis in a patient with a hepatic stent-graft.

CONCLUSIONS

Irrespective of their etiology and acuteness, VAAs can be treated with stent-grafts, with an excellent clinical long-term outcome and a high patency rate.

Safe, effective and durable epicardial left atrial appendage clip occlusion in patients with atrial fibrillation undergoing cardiac surgery: first long-term results from a prospective device trial

OBJECTIVES

Atrial fibrillation (AF) is a significant risk factor for embolic stroke originating from the left atrial appendage (LAA). This is the first report of long-term safety and efficacy data on LAA closure using a novel epicardial LAA clip device in patients undergoing cardiac surgery.

METHODS

Forty patients with AF were enrolled in this prospective 'first-in-man' trial. The inclusion criterion was elective cardiac surgery in adult patients with AF for which a concomitant ablation procedure was planned. Intraoperative transoesophageal echocardiography (TEE) was used to exclude LAA thrombus at baseline and evaluate LAA perfusion after the procedure, while computed tomography (CT) was used for serial imagery workup at baseline, 3-, 12-, 24- and 36-month follow-up.

RESULTS

Early mortality was 10% due to non-device-related reasons, and thus 36 patients were included in the follow-up consisting of 1285 patient-days and mean duration of 3.5 ± 0.5 years. On CT, clips were found to be stable, showing no secondary dislocation 36 months after surgery. No intracardial thrombi were seen, none of the LAA was reperfused and in regard to LAA stump, none of the patients demonstrated a residual neck >1 cm. Apart from one unrelated transient ischaemic attack (TIA) that occurred 2 years after surgery in a patient with carotid plaque, no other strokes and/or neurological events demonstrated in any of the studied patients during follow-up.

CONCLUSION

This is the first prospective trial in which concomitant epicardial LAA occlusion using this novel epicardial LAA clip device is 100% effective, safe and durable in the long term. Closure of the LAA by epicardial clipping is applicable to all-comers regardless of LAA morphology. Minimal access epicardial LAA clip closure may become an interesting therapeutic option for patients in AF who are not amenable to anticoagulation and/or catheter closure. Further data are necessary to establish LAA occlusion as a true and viable therapy for stroke prevention.

CLINICAL TRIAL REGISTRATION

The trial is registered at www.ClinicalTrials.gov, reference: NCT00567515.

Diagnostic performance of a non-contrast-enhanced magnetic resonance imaging protocol for potential living related kidney donors

RATIONALE AND OBJECTIVES

The objective of the study was to evaluate the performance of a non-contrast-enhanced magnetic resonance (MR) imaging protocol for preoperative screening of living related kidney donors.

MATERIALS AND METHODS

Forty consecutive subjects (mean age 52.2 ± 11.3 years, range 29-73 years) underwent MR imaging with T2-weighted sequences (coronal and axial plane), with a non-contrast-enhanced respiratory-gated three-dimensional steady state free precession MR angiography (NCE-MRA) sequence and with contrast-enhanced magnetic resonance MR angiography (CE-MRA) sequences in the arterial and venous phases. Two blinded readers independently assessed arterial and venous anatomy and potential kidney lesions. Results of non-contrast-enhanced images were compared to CE-MRA and in a subgroup of 21 subjects to surgery as standard of reference.

RESULTS

Regarding arterial anatomy, NCE-MRA yielded sensitivity, specificity, and accuracy of 100%, 89%, and 91% compared to CE-MRA. Three kidneys were found to have more accessory renal arteries at NCE-MRA than at CE-MRA. In the subgroup of 21 subjects, 1 surgically proven accessory artery was depicted with NCE-MRA but not with CE-MRA. Accuracy of T2-weighted images regarding accessory veins or variant venous course was 99%, with one missed circumaortic vein on T2-weighted images. Two simple cysts were missed on T2-weighted and NCE-MRA but not on CE-MRA images.

CONCLUSION

A non-contrast-enhanced MR imaging protocol including NCE-MRA and T2-weighted images allows for the accurate screening of living related kidney donors and may serve as an alternative to CE-MRA.

Table-mounted ring retractor for consistent visualization in endoscopy-assisted anterior reconstruction of burst fractures of the thoracolumbar junction

The authors tested an autoclavable external ring retractor, fixed to the operation table, for the endoscopic reconstruction of anterior column injuries of the thoracolumbar junction. It served as a retractor for the diaphragm, and offered a stable support for the scope and other instruments, making an assistant superfluous. Moreover, it allowed bimanual manipulation. Of course, the two-dimensional image, provided by the scope, necessitated proper eye-hand coordination. Twenty-eight consecutive patients underwent either a monosegmental (n = 10) or a bisegmental (n = 18) anterior stabilization in the area Th11L1. Three portals were necessary, but an assistant was not needed. The overall (mean +/- SD) operating time was 196 +/- 56 min, the blood loss was 804 +/- 719 mL. Intraoperatively, one epidural bleeding and a single screw cut-out occurred. All complications were managed endoscopically. Postoperatively, evacuation of a haemothorax (n = 1) was necessary. In all patients, wounds and fractures healed uneventfully. The combination of the endoscopic technique and the retractor system was feasible, successful, safe, and time efficient. Moreover, it allowed for anterior instrumentation of thoracolumbar fractures by a single surgeon. It became the standard approach in the authors' department.

Raw data-based iterative reconstruction in body CTA: evaluation of radiation dose saving potential

OBJECTIVE

To evaluate prospectively, in patients undergoing body CTA, the radiation dose saving potential of raw data-based iterative reconstruction as compared to filtered back projection (FBP).

METHODS

Twenty-five patients underwent thoraco-abdominal CTA with 128-slice dual-source CT, operating both tubes at 120 kV. Full-dose (FD) images were reconstructed with FBP and were compared to half-dose (HD) images with FBP and HD-images with sinogram-affirmed iterative reconstruction (SAFIRE), both reconstructed using data from only one tube-detector-system. Image quality and sharpness of the aortic contour were assessed. Vessel attenuation and noise were measured, contrast-to-noise-ratio was calculated.

RESULTS

Noise as image quality deteriorating artefact occurred in 24/25 (96%) HD-FBP but not in FD-FBP and HD-raw data-based iterative reconstruction datasets (p < 0.001). Other artefacts occurred with similar prevalence among the datasets. Sharpness of the aortic contour was higher for FD-FBP and HD-raw data-based iterative reconstruction as compared to HD-FBP (p < 0.001). Aortoiliac attenuation was similar among all datasets (p > 0.05). Lowest noise was found for HD-raw data-based iterative reconstruction (7.23HU), being 9.4% lower than that in FD-FBP (7.98HU, p < 0.05) and 30.8% lower than in HD-FBP images (10.44HU, p < 0.001). Contrast-to-noise-ratio was lower in HD-FBP (p < 0.001) and higher in HD-raw data-based iterative reconstruction (p < 0.001) as compared to FD-FBP.

CONCLUSION

Intra-individual comparisons of image quality of body CTA suggest that raw data-based iterative reconstruction allows for dose reduction >50% while maintaining image quality. Key Points • Raw data-based iterative reconstruction reduces image noise and improves image quality as compared to filtered back projection • At a similar radiation dose, raw data-based iterative reconstruction improves the sharpness of vessel contours • In body CTA a dose reduction of >50% might be possible when using raw data-based iterative reconstructions, while image quality can be maintained.