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1.
Eur J Radiol ; 171: 111312, 2024 Feb.
Article in English | MEDLINE | ID: mdl-38237520

ABSTRACT

BACKGROUND: Contrast-enhanced breast MRI and recently also contrast-enhanced mammography (CEM) are available for breast imaging. The aim of the current overview is to explore existing evidence and ongoing challenges of contrast-enhanced breast imaging. METHODS: This narrative provides an introduction to the contrast-enhanced breast imaging modalities breast MRI and CEM. Underlying principle, techniques and BI-RADS reporting of both techniques are described and compared, and the following indications and ongoing challenges are discussed: problem-solving, high-risk screening, supplemental screening in women with extremely dense breast tissue, breast implants, neoadjuvant systemic therapy (NST) response monitoring, MRI-guided and CEM- guided biopsy. RESULTS: Technique and reporting for breast MRI are standardised, for the newer CEM standardisation is in progress. Similarly, compared to other modalities, breast MRI is well established as superior for problem-solving, screening women at high risk, screening women with extremely dense breast tissue or with implants; and for monitoring response to NST. Furthermore, MRI-guided biopsy is a reliable technique with low long-term false negative rates. For CEM, data is as yet either absent or limited, but existing results in these settings are promising. CONCLUSION: Contrast-enhanced breast imaging achieves highest diagnostic performance and should be considered essential. Of the two contrast-enhanced modalities, evidence of breast MRI superiority is ample, and preliminary results on CEM are promising, yet CEM warrants further study.


Subject(s)
Breast Neoplasms , Mammography , Female , Humans , Breast/diagnostic imaging , Breast Density , Breast Neoplasms/diagnostic imaging , Contrast Media , Magnetic Resonance Imaging/methods , Mammography/methods
2.
Cardiovasc Intervent Radiol ; 45(1): 21-28, 2022 Jan.
Article in English | MEDLINE | ID: mdl-34734334

ABSTRACT

PURPOSE: To investigate efficacy and patency status of stent graft implantation in the treatment of hepatic artery pseudoaneurysm. MATERIALS AND METHODS: A retrospective analysis of patients who had undergone endovascular treatment of hepatic artery pseudoaneurysms between 2011 and 2020 was performed. Medical records were examined to obtain patients' surgical histories and to screen for active bleeding. Angiographic data on vascular access, target vessel, material used and technical success, defined as the exclusion of the pseudoaneurysm by means of a stent graft with sufficient control of bleeding, were collected. Vessel patency at follow-up CT was analyzed and classified as short-term (< 6 weeks), mid-term (between 6 weeks and 1 year), and long-term patency (> 1 year). In case of stent occlusion, collateralization and signs of hepatic hypoperfusion were examined. RESULTS: In total, 30 patients were included and of these, 25 and 5 had undergone stent graft implantation and coiling, respectively. In patients with implanted stent grafts, technical success was achieved in 23/25 patients (92%). Follow-up CT scans were available in 16 patients, showing stent graft patency in 9/16 patients (56%). Short-term, mid-term, and long-term short-term stent patency was found in 81% (13/16), 40% (4/10), and 50% (2/4). In patients with stent graft occlusion, 86% (6/7) exhibited maintenance of arterial liver perfusion via collaterals and 14% (1/7) exhibited liver abscess during follow-up. CONCLUSION: Stent graft provides an effective treatment for hepatic artery pseudoaneurysms. Even though patency rates decreased as a function of time, stent occlusion was mainly asymptomatic due to sufficient collateralization.


Subject(s)
Aneurysm, False , Blood Vessel Prosthesis Implantation , Aneurysm, False/diagnostic imaging , Aneurysm, False/surgery , Blood Vessel Prosthesis , Follow-Up Studies , Hepatic Artery/diagnostic imaging , Hepatic Artery/surgery , Humans , Retrospective Studies , Stents , Treatment Outcome , Vascular Patency
3.
Cardiovasc Intervent Radiol ; 43(6): 875-881, 2020 Jun.
Article in English | MEDLINE | ID: mdl-31974746

ABSTRACT

PURPOSE: To investigate whether sarcopenia and myosteatosis correlate with the degree of hypertrophy (DH) and kinetic growth rate (KiGR) of the future liver remnant (FLR) in patients with colorectal liver metastases undergoing portal vein embolization (PVE) in preparation for right hepatectomy. MATERIALS AND METHODS: Forty-two patients were included. Total liver volume and FLR volume were measured before and 2-4 weeks after PVE. KiGR of the FLR was calculated. Sarcopenia was assessed using the total psoas muscle volume (PMV), the psoas muscle cross-sectional area (PMCS) and the total skeletal muscle index (L3SMI) at the level of 3rd lumbar vertebra. Degree of myosteatosis was assessed by mean muscle attenuation at L3 (L3MA). Correlations between muscle indices and DH and KiGR were assessed using simple linear regression analyses. RESULTS: Mean DH was 8.9 ± 5.7%, and mean KiGR was 3.6 ± 2.3. Mean PMV was 55.56 ± 14.19 cm3/m3, mean PMCS was 8.76 ± 2.3 cm2/m2, mean L3SMI was 45.6 ± 9.89 cm2/m2, and mean L3MA was 27.9 ± 18.6 HU. There was a strong positive correlation between PMV and DH (R = 0.503, p = 0.001) and PMV and KiGR (R = 0.545, p < 0.001). Furthermore, there was a moderate correlation between PMCS and KiGR (R = 0.389, p = 0.014). L3SMI and L3MA were neither associated with DH (p = 0.390 and p = 0.768, respectively) nor with KiGR (p = 0.188 and p = 0.929, respectively). CONCLUSION: We identified a positive correlation between PMV and PMCS, as markers for sarcopenia, and the KiGR of the FLR after PVE. PMV and PMCS might therefore aid to identify patients who are poor candidates for FLR augmentation using PVE alone.


Subject(s)
Colorectal Neoplasms/pathology , Embolization, Therapeutic/methods , Liver Neoplasms/secondary , Liver Neoplasms/therapy , Liver/anatomy & histology , Portal Vein/diagnostic imaging , Sarcopenia/physiopathology , Adult , Aged , Female , Humans , Liver/growth & development , Male , Middle Aged , Organ Size , Retrospective Studies , Sarcopenia/diagnostic imaging , Tomography, X-Ray Computed/methods , Ultrasonography, Interventional/methods
4.
Cardiovasc Intervent Radiol ; 42(10): 1494-1499, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31363899

ABSTRACT

INTRODUCTION: Significant intratumoral shunts between tumor-supplying arteries and portal or liver veins are a contraindication for transarterial therapy of HCC because interventional treatment of these shunts is frequently insufficient. Sorafenib has anti-angiogenic effects and is indicated for palliative treatment of patients with HCC. Here, we report our experience with the use of sorafenib for the closure of intratumoral shunts in patients scheduled for transarterial therapy of HCC. MATERIALS AND METHODS: Three patients with HCC, aged 65, 82 and 79 years, exhibited a significant intratumoral shunting from tumor artery to portal (n = 1) or liver veins (n = 2). In all cases, intratumoral shunting had already been suspected based on pre-interventional CT angiography, and DSA confirmed the shunt. Oral sorafenib (800 mg/day) was administered for at least four weeks, only and specifically to occlude the shunt. Hereafter, patients were re-evaluated by CT and DSA. RESULTS: All patients tolerated the full prescribed dose for at least 4 weeks. In one case, therapy was prolonged with an adapted dose (400 mg/day) due to sorafenib-related hand-foot syndrome. After sorafenib treatment, CT and DSA confirmed a complete closure of intratumoral shunts for all patients. No tumor progression was observed. All three patients hereafter underwent successful transarterial treatment by TACE (n = 2) or TARE (n = 1) without complications. Progression-free survival according to mRECIST was 501, 397 and 599 days, respectively. CONCLUSION: Even short-term oral sorafenib seems to effectively close intratumoral shunts in patients with HCC and thus might enable transarterial treatment of these patients.


Subject(s)
Antineoplastic Agents/therapeutic use , Carcinoma, Hepatocellular/blood supply , Liver Neoplasms/blood supply , Neovascularization, Pathologic/drug therapy , Sorafenib/therapeutic use , Aged , Aged, 80 and over , Angiography, Digital Subtraction , Antineoplastic Agents/administration & dosage , Carcinoma, Hepatocellular/complications , Carcinoma, Hepatocellular/diagnostic imaging , Chemoembolization, Therapeutic , Female , Humans , Infusions, Intra-Arterial , Liver/blood supply , Liver/diagnostic imaging , Liver Neoplasms/complications , Liver Neoplasms/diagnostic imaging , Male , Neovascularization, Pathologic/complications , Neovascularization, Pathologic/diagnostic imaging , Retrospective Studies , Sorafenib/administration & dosage , Time , Tomography, X-Ray Computed , Treatment Outcome
5.
Radiologe ; 59(6): 533-540, 2019 Jun.
Article in German | MEDLINE | ID: mdl-31069426

ABSTRACT

BACKGROUND: Carbon dioxide (CO2) is a very good and validated alternative to iodine-containing contrast media in diagnostic and interventional angiography. Nevertheless, its routinely use is still limited to specialized centers. OBJECTIVE: The presentation of the current role and limitations of CO2 in diagnostic and interventional angiography (venous and arterial). MATERIAL AND METHODS: A comprehensive review of the literature regarding CO2 angiography (physical features, indications, contraindications, applications) was carried out. RESULTS: The results show that CO2 can be used as a reliable alternative for diagnostic angiography and to support interventions in many arterial and venous vascular territories. An exception is the intra-arterial use of CO2 above the diaphragm due to the risk of severe myocardial and cerebral complications, which represents the most important contraindication. Moreover, due to its very low viscosity, CO2 is more effective than iodine-containing contrast media in detecting bleeding arising from small vessels. CONCLUSION: The CO2 angiography is a safe and effective technique and can be used as valid alternative. In several clinical cases it even offers some advantages compared to iodine-containing contrast media.


Subject(s)
Angiography, Digital Subtraction , Carbon Dioxide , Contrast Media , Arteries , Contraindications , Humans
6.
Cardiovasc Intervent Radiol ; 42(10): 1475-1482, 2019 Oct.
Article in English | MEDLINE | ID: mdl-31119355

ABSTRACT

PURPOSE: To investigate local and systemic effects of transpulmonary chemoembolization (TPCE) with degradable starch microspheres (DSM) and doxorubicin. The long-term goal is to establish DSM-TPCE as a treatment option for pulmonary malignancies. MATERIALS AND METHODS: Nine pigs underwent TPCE of either the right or left lower lobe pulmonary artery (LLPA) and bland embolization (TPE) of the contralateral LLPA. Before the procedures, macroaggregated albumin (MAA) particles were injected into both LLPAs, to exclude systemic shunting. Pulmonary arterial pressure, heart rate and oxygenation were recorded immediately before and at 1, 3, 5 and 10 min after treatment. To investigate possible nontarget embolization, animals underwent cerebral MRI (cMRI). We killed the animals after a contrast-enhanced chest computed tomography (CT) and performed a pathologic examination at 12 h (3), 24 h (3) and 72 h (3) after treatment. RESULTS: All experiments were technically successful. Mean injected DSM dose until stasis was similar in TPCE and TPE (4.3 ± 1.4 vs. 4.0 ± 1.4 mL). Pulmonary arterial pressure increased significantly 3 min after treatment (TPE: 17 ± 5 vs. 27 ± 7 mmHg; TPCE: 22 ± 6 vs. 36 ± 8 mmHg). No significant changes in heart rate or peripheral oxygenation levels occurred. We observed no evidence of structural lung damage or permanent perfusion disruption on CT. MAA test injection and cMRI revealed no shunting or nontarget embolization. The pathologic assessment revealed nonspecific local inflammation of the lung parenchyma. CONCLUSION: In this large-animal model, TPCE and TPE appear feasible and safe. We observed a mild increase in pulmonary arterial pressure. Nontarget embolization did not occur. TPCE, as well as TPE, did not cause structural damage to the normal lung parenchyma.


Subject(s)
Chemoembolization, Therapeutic/methods , Lung/drug effects , Starch/administration & dosage , Animals , Antibiotics, Antineoplastic/administration & dosage , Doxorubicin/administration & dosage , Female , Lung/diagnostic imaging , Models, Animal , Swine , Tomography, X-Ray Computed/methods
7.
J Orthop ; 14(1): 95-103, 2017 Mar.
Article in English | MEDLINE | ID: mdl-27829733

ABSTRACT

PURPOSE: The aim was to prove the possibility of creating an exact module of knee cartilage defects using 3D printing. METHODS: Defects were created in cadaver knees. CT-arthrography and 3-Tesla MRI were performed. Based on CTA images a model of the cartilage was created using 3D printing. Defect-sizes in the imaging modalities were compared. RESULTS: Estimated lesion area in 3D model differed approximately 5% comparing to the defect sizes in knees. MRI underestimated the defect on average of 12%, whereas the CTA overestimated the defect about 3%. CONCLUSIONS: We proved the feasibility of creating an accurate module of knee cartilage.

8.
Rofo ; 188(7): 676-83, 2016 Jul.
Article in English | MEDLINE | ID: mdl-27248649

ABSTRACT

PURPOSE: To evaluate transarterial alcohol-lipiodol therapy (TAL) with low concentrations of alcohol for the treatment of hepatocellular carcinoma (HCC). MATERIALS AND METHODS: 17 patients (69.3 ±â€Š10.7a, 13 male, 4 female) with previously untreated HCC (tumor diameter: 7.7 ±â€Š5.8 cm), who underwent 20 transarterial alcohol-lipiodol injections, were evaluated retrospectively. 14 patients had HCC with coexistent cirrhosis (Child-A n = 9, Child-B n = 4, Child-C n = 1). 9 patients presented an Okuda stage I, 7 patients an Okuda stage II and 1 patient an Okuda stage III. Infiltration of the portal vein was seen in 3 patients. RESULTS: 15 patients underwent TAL with an alcohol:lipiodol ratio of 1:2, another one with a ratio of 1:3 and yet another one with a ratio of 1:5. The median survival was 23 months, and the 1-year and 2-year survival rates were 62.7 % and 31.4 %, respectively. The median survival of patients with HCC < 7.5 cm (n = 10) was 25 months and significantly (p = 0.009) higher than for patients with HCC ≥ 7.5 cm (n = 7; 3 months). Tumor diameters ≥ 7.5 cm were associated with worse lipiodol-contrasting of HCC. Intrainterventional side effects were only feelings of slight abdominal pressure in 2 of 20 interventions. Postinterventional, mild side effects were observed after 3 interventions (abdominal pain n = 1, thoracic pain n = 1, fever n = 1). Serious complications were not observed, in particular there was no decompensation of liver cirrhosis. CONCLUSION: TAL with low concentrations of alcohol was a safe and effective treatment in our cohort in spite of extensive tumors and impaired liver function. TAL could be a treatment option for patients who cannot receive other therapies (e. g. TACE, RFA) because of their advanced tumor disease, liver cirrhosis or other contraindications. KEY POINTS: • TAL can be performed safely in advanced tumor disease and liver cirrhosis Citation Format: • Mohné F, Meyer C, Kuhl CK et al. Transarterial Alcohol-Lipiodol Therapy in Patients with Hepatocellular Carcinoma Using Low Alcohol Concentrations. Fortschr Röntgenstr 2016; 188: 676 - 683.


Subject(s)
Ablation Techniques/methods , Chemoembolization, Therapeutic/methods , Ethanol/administration & dosage , Ethiodized Oil/administration & dosage , Liver Neoplasms/diagnostic imaging , Liver Neoplasms/therapy , Aged , Aged, 80 and over , Antineoplastic Agents/administration & dosage , Dose-Response Relationship, Drug , Drug Therapy, Combination/methods , Female , Humans , Injections, Intra-Arterial , Magnetic Resonance Imaging/methods , Male , Middle Aged , Retrospective Studies , Tomography, X-Ray Computed/methods , Treatment Outcome
9.
Cardiovasc Intervent Radiol ; 39(4): 575-81, 2016 Apr.
Article in English | MEDLINE | ID: mdl-26797022

ABSTRACT

PURPOSE: Hepatic artery pseudoaneurysms are a rare but potentially life-threatening complication of major pancreaticobiliary surgery. We evaluated the safety and efficacy of endovascular stentgraft implantation for the management of such vascular lesions. MATERIALS AND METHODS: Between May 2013 and October 2015, ten patients with postoperative hepatic artery pseudoaneurysm, of which eight presented with active hemorrhage, were treated with endovascular stentgraft implantation. All patients had undergone major pancreatic or hepatic surgery before (pylorus-preserving pancreaticoduodenectomy, pancreatectomy, hemihepatectomy, extended hemihepatectomy). The pseudoaneurysms were diagnosed 13-202 days after surgery and were associated with postsurgical complications (e.g., leakage of pancreaticojejunal anastomosis). RESULTS: In 9/10 patients, the pseudoaneurysm was completely excluded via stentgraft implantation. In 1/10 patient, the pseudoaneurysm ruptured during the procedure and was successfully treated by immediate open surgery. In 1/10 patient, a second intervention was performed after 6 days because of rebleeding; this was successfully treated by implantation of a second overlapping stentgraft. Mean follow-up time is 51 days. None of the patients died due to stentgraft- or aneurysm-related complications. Further episodes of hemorrhage were not observed. In one patient, clinically asymptomatic complete occlusion of the stentgraft was discovered at follow-up imaging. CONCLUSION: Stentgraft implantation is a safe and effective technique to treat hepatic artery pseudoaneurysms related to major pancreatic or hepatic surgery, especially in the setting of acute hemorrhage.


Subject(s)
Aneurysm, False/diagnostic imaging , Aneurysm, False/surgery , Hepatic Artery/diagnostic imaging , Hepatic Artery/surgery , Aged , Blood Vessel Prosthesis , Blood Vessel Prosthesis Implantation , Endovascular Procedures , Humans , Male , Middle Aged , Postoperative Care , Prosthesis Implantation , Stents
10.
Rofo ; 187(7): 584-8, 2015 Jul.
Article in English | MEDLINE | ID: mdl-26090651

ABSTRACT

PURPOSE: To determine effectiveness of lymphatic interventional procedures for treatment of chylothorax. MATERIAL AND METHODS: Analysis of interventions performed from 2001 to 2014. RESULTS: In 21 patients with therapy resistant chylothorax a lymphatic radiological intervention was attempted, which could be performed in 19 cases: 17 thoracic duct embolizations (15 transabdominal, one transzervical and one retrograde transvenous procedure), 2 percutaneous destructions of lymphatic vessels, one CT-guided injection of ethanol next to a duplicated thoracic duct. Fourteen of seventeen (82.3 %) of the technically successful embolizations lead to clinical cure. This encluded three patients with prior unsuccessful surgical thoracic duct ligation. Also the injection of ethanol was clinically effective. Complications were a bile peritonitis requiring operation, and one clinical deterioration of unknown cause. CONCLUSION: Interventional lymphatic procedures allow for effective treatment in many cases of chylothorax, and should be considered early during treatment. KEY POINTS: • Thoracic duct embolization is an effective treatment method for chylothorax. • If embolization is impossible, percutaneous lymphatic destruction or injection of sclerosants/tissue adhesive next to the thoracic duct may be tried.


Subject(s)
Chylothorax/therapy , Embolization, Therapeutic/methods , Hemostatics/administration & dosage , Lymph Node Excision/methods , Radiography, Interventional/methods , Surgery, Computer-Assisted/methods , Adult , Aged , Chylothorax/diagnostic imaging , Female , Humans , Male , Middle Aged , Tomography, X-Ray Computed/methods , Treatment Outcome
11.
ScientificWorldJournal ; 2014: 514942, 2014.
Article in English | MEDLINE | ID: mdl-24737976

ABSTRACT

PURPOSE: To investigate the safety and feasibility of the use of a vascular closure device (VCD) after endovascular procedures in swine. MATERIAL AND METHODS: In a study on endovascular therapy, VCD (StarClose, Abbott Vascular, Il, USA) was used in 20 female swines to achieve immediate hemostasis after percutaneous right femoral artery (FA) access. 10 animals were sacrificed immediately after the study and 10 animals were sacrificed 28 days after the initial study. To ensure complete hemostasis and patency of the femoral artery, a CT-angiography of the puncture site was performed on day 1 (acute and chronic group) and day 28 (chronic group). After the sacrifice, the femoral artery was explanted and examined macroscopically for signs of VCD dysfunction. RESULTS: Technical success rate was 100% with immediate hemostasis being achieved in all animals. No animals showed evidence of hematoma. During explantation, only small traces of coagulated blood were found in the acute group, while there were no signs of hematoma in the chronic group. CT-angiography immediately after VCD application as well as before sacrifice (chronic group) showed patency of the FA in all cases. CONCLUSION: The use of VCD to achieve hemostasis after endovascular studies in swine is feasible and safe.


Subject(s)
Endovascular Procedures/methods , Vascular Closure Devices , Animals , Female , Femoral Artery/surgery , Hematoma/prevention & control , Swine
12.
Cardiovasc Intervent Radiol ; 37(4): 1053-61, 2014 Aug.
Article in English | MEDLINE | ID: mdl-24390361

ABSTRACT

PURPOSE: To evaluate heating efficacy of superparamagnetic iron oxide nanoparticles (SPIO) for electromagnetic ablation (EMA) of osteoid osteoma (OO) using an ex vivo model compared to radiofrequency ablation (RFA) and microwave ablation (MWA). METHODS: A model for OO using sliced bovine tibia and sliced muscle tissue was developed. A bone cavity filled with either a mixture of SPIO and agarose or pure agarose (control group) was established. EMA was performed using an experimental system, RFA and MWA using clinically approved systems, and the ablation protocols recommended by the vendor. For temperature measurements, fiberoptic temperature probes were inserted inside the cavity, on the outside of the periosteum, and at a 5 mm distance to the periosteum. RESULTS: Maximum temperatures with or without SPIO in the nidus were as follows: EMA: 79.9 ± 2.5/22.3 ± 0.7 °C; RFA: 95.1 ± 1.8/98.6 ± 0.9 °C; MWA: 85.1 ± 10.8/83.4 ± 9.62 °C. In RFA with or without SPIO significantly higher temperatures were achieved in the nidus compared to all other groups (p < 0.05). In MWA significantly higher temperatures were observed in the 5 mm distance to the periosteum compared to EMA and RFA with or without SPIO (p < 0.05). In MWA temperature decrease between nidus and the 5 mm distance to the periosteum was significantly lower than in RFA with or without SPIO (p < 0.0001). In MWA without SPIO temperature decrease was significantly lower than in the EMA group (p < 0.05). CONCLUSION: In the experimental setting, ablation of OO is safe and effective using EMA. It is less invasive than RFA and MWA, and it theoretically allows repeated treatments without repeated punctures. In comparison, the highest temperatures in the nidus are reached using RFA.


Subject(s)
Catheter Ablation/methods , Dextrans/pharmacology , Microwaves/therapeutic use , Osteoma, Osteoid/surgery , Animals , Cattle , Disease Models, Animal , Electromagnetic Fields , Equipment Design , Magnetite Nanoparticles , Temperature , Tibia
13.
Rofo ; 185(2): 128-35, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23196833

ABSTRACT

PURPOSE: To systematically investigate the impact of image acquisition and contrast injection parameters for CO2-enhanced CT angiography (CTA) of the aorto-iliac and peripheral arteries in a pig model using commercially available equipment. The aim was to establish an imaging protocol that is ready for use in human subjects. MATERIALS AND METHODS: Three domestic swine underwent CO2-CTA with varying injection parameters: pitch (1.0, 3.0), injection pressure (0.7 bar, 1.0 bar, 1.3 bar) and scan delay (2 s, 4 s, 6 s). Objective (vessel diameter) and subjective (image quality) parameters and applied radiation doses were systematically evaluated. To ensure clinical applicability of the setting, only approved catheters/injectors and standard injection parameters were evaluated. RESULTS: The image quality scores were superior and the vessel diameter was larger with high pitch in comparison to standard pitch (diameters: 4.7 ± 2.0 mm vs. 3.6 ± 2.1 mm, p = 0.0040, scores: 2.6 ± 1.1 vs. 2.0 ± 1.1, p = 0.0038). High injection pressure (1.3 bar) improved the image quality as assessed by subjective and objective ratings (diameters: 3.6 ± 2.0 mm, 4.0 ± 2.1 mm and 4.6 ± 2.1 mm, for 0.7, 1.0 and 1.3 bar, p-values ≤ 0.0052, scores: 1.9 ± 1.1, 2.3 ± 1.1 and 2.7 ± 1.2, p-values ≤ 0.0017), the same was observed for a shorter injection delay (diameters: 3.5 ± 2.0 mm, 4.2 ± 2.1 mm and 4.8 ± 2.1 mm, for 6 s, 4 s, and 2 s, p ≤ 0.0022, scores: 1.9 ± 1.1, 2.3 ± 1.1 and 2.7 ± 1.1, p-values ≤ 0.0013). The dose length products were 239 ± 47 mGycm (high pitch) and 565 ± 63 mGycm (standard pitch, p-values < 0.0001). CONCLUSION: A higher pitch, shorter delay and higher injection pressure improve image quality in CO2-enhanced CTA. Since commercially available, clinically approved equipment was used. The protocol is now ready for use in human subjects.


Subject(s)
Angiography/methods , Carbon Dioxide/administration & dosage , Contrast Media/administration & dosage , Radiographic Image Enhancement/methods , Tomography, X-Ray Computed/methods , Animals , Dose-Response Relationship, Drug , Models, Animal , Pressure , Reproducibility of Results , Sensitivity and Specificity , Swine
14.
Eur Radiol ; 22(12): 2670-8, 2012 Dec.
Article in English | MEDLINE | ID: mdl-22752407

ABSTRACT

OBJECTIVES: To compare image quality in coronary artery computed tomography angiography (cCTA) using reconstructions with automated phase detection and Reconstructions computed with Identical Filling of the heart (RIF). METHODS: Seventy-four patients underwent ECG-gated dual source CT (DSCT) between November 2009 and July 2010 for suspected coronary heart disease (n = 35), planning of transcatheter aortic valve replacement (n = 34) or evaluation of ventricular function (n = 5). Image data sets by the RIF formula and automated phase detection were computed and evaluated with the AHA 15-segment model and a 5-grade Likert scale (1: poor, 5: excellent quality). Subgroups regarding rhythm (sinus rhythm = SR; arrhythmia = ARR) and potential premedication were evaluated by a per-segment, per-vessel and per-patient analysis. RESULTS: RIF significantly improved image quality in 10 of 15 coronary segments (P < 0.05). More diagnostic segments were provided by RIF regarding the entire cohort (n = 693 vs. 590, P < 0.001) and all of the subgroups (e.g. ARR: n = 143 vs. 72, P < 0.001). In arrhythmic patients (n = 19), more diagnostic vessels (e.g. LAD: n = 10 vs. 3; P < 0.014) and complete data sets (n = 7 vs. 1; P < 0.001) were produced. CONCLUSIONS: RIF reconstruction is superior to automatic diastolic non-edited reconstructions, especially in arrhythmic patients. RIF theory provides a physiological approach for determining the optimal image reconstruction point in ECG-gated CT angiography. KEY POINTS: Conventional CT coronary angiography suffers from numerous artefacts in patients with irregular rhythms. Coronary computed tomography angiograms (cCTA) were reconstructed with identical cardiac filling (RIF). RIF reconstructions provide improved image quality compared to non-edited standard reconstructions. RIF theory links physiology with cardiac CT.


Subject(s)
Coronary Angiography/methods , Coronary Artery Disease/diagnostic imaging , Coronary Artery Disease/physiopathology , Radiographic Image Interpretation, Computer-Assisted/methods , Tomography, X-Ray Computed/methods , Aged , Algorithms , Cardiac-Gated Imaging Techniques , Chi-Square Distribution , Contrast Media , Female , Humans , Iohexol/analogs & derivatives , Male , Radiation Dosage , Reproducibility of Results , Retrospective Studies , Statistics, Nonparametric
15.
Rofo ; 184(6): 542-7, 2012 Jun.
Article in English | MEDLINE | ID: mdl-22516963

ABSTRACT

PURPOSE: Evaluation of the maximum temperatures and ablation volumes in microwave ablation (MWA) after injection of different concentrations of silicon carbide (SiC) particles in an ex-vivo bovine liver model. MATERIALS AND METHODS: 15 ml of different concentrations of SiC particles (20 vol% SiC; 50 vol% SiC) mixed with 2 % gelatin were injected into an ex-vivo bovine liver. As a reference group, 2 % gelatin without SiC was injected. MWA was performed using a clinical MWA system with different generator settings (10 - 45 W/10 minutes). The temperature was measured at a distance of 5 mm and 10 mm from the applicator. Afterwards the liver tissue was sliced along the short and long axis, the ablation zones were measured on the x, y and z-axis and the ablation volume was calculated. All experiments were performed 5 times (total: 40 experiments). RESULTS: The average maximum temperatures measured at a generator setting of 45 W at a distance of 5 mm from the applicator were 103.4 ± 4.6 °C (20 vol% SiC), 103.3 ± 6.5 °C (50 vol% SiC) and 96.0 ± 4.2 °C in the control group (0 vol% SiC). At 45 W, injection of 20 vol% SIC caused a significantly higher maximum temperature than that achieved in the control group (p = 0.016). No significant temperature increase compared to the control group could be measured using 50 vol% SiC. The mean ablation volumes at 45 W and 20 vol% SiC and 50 vol% SiC were significantly larger (172.7 ± 31.5 ml and 171.0 ± 34.7 ml, respectively) than those achieved in the control group (111.2 ± 23.8 ml) (p = 0.027 and p = 0.045). CONCLUSION: In an ex-vivo bovine liver model, the SiC particles demonstrated an enhancing effect of MWA with respect to maximum temperatures and ablation volume. Therefore, SiC is a promising candidate for enhancing MWA in vivo.


Subject(s)
Biocompatible Materials , Carbon Compounds, Inorganic/administration & dosage , Catheter Ablation/instrumentation , Catheter Ablation/methods , Disease Models, Animal , Liver/surgery , Silicon Compounds/administration & dosage , Animals , Cattle , Dose-Response Relationship, Drug , In Vitro Techniques , Injections , Microwaves , Particle Size , Temperature
16.
Eur J Med Res ; 13(6): 287-91, 2008 Jun 24.
Article in English | MEDLINE | ID: mdl-18558555

ABSTRACT

INTRODUCTION: Among all imaging modalities, MRI of the prostate has the highest sensitivity to predict extracapsular tumor spread, seems to have added value for the preoperative treatment planning. It is an adjunct tool in patients with high suspicion of prostate cancer and so far negative TRUS-guided biopsies. Due to the higher intrinsic signal, it is expected that 3.0T enables to image the prostate without endorectal coil. Aim of this study was to evaluate the diagnostic accuracy of phased array coil 3.0T MRI in patients with suspicion of prostate cancer. MATERIAL AND METHODS: A high spatial resolution T2-w 3.0T pulse sequence (0.47 x 0.47 x 3mm voxel size) was performed in 26 patients prior to US-guided biopsy. Qualitative analysis comprised visual signal to noise, tissue contrasts and motion artifacts. MR diagnoses were correlated with histology. Diagnostic indices for the detection of prostate cancer in the peripheral zone were calculated. RESULTS: Histopathologic examination revealed pro?state cancer in 12 and benign prostate disorders in 14 patients. Motion artifacts due to peristalsis were rated moderate. Mean visual signal to noise was high. Contrast between peripheral and central zone of the prostate was excellent. MRI had 4 false negative and 2 false positive diagnoses (sensitivity 66.7 %, specificity 86.7 % diagnostic accuracy 76.9%). CONCLUSION: At 3.0T, diagnostic indices for cancer detection seem to be comparable to data reported about endorectal 1.5T MRI. Thus 3.0 T offers new options for MR imaging of the prostate in selected patients who cannot or are not willing to be examined with the endorectal coil.


Subject(s)
Magnetic Resonance Imaging/methods , Prostate/pathology , Prostatic Neoplasms/diagnosis , Prostatic Neoplasms/pathology , Aged , Biopsy , False Positive Reactions , Humans , Image Processing, Computer-Assisted , Magnetic Resonance Spectroscopy/methods , Male , Middle Aged , Radiology/methods
18.
Radiologe ; 48(4): 358-66, 2008 Apr.
Article in German | MEDLINE | ID: mdl-18369582

ABSTRACT

In oncologic patients, staging of the disease extent is of paramount importance. Imaging studies are used to decide whether the patient is a surgical candidate; if this is the case, imaging is used for detailed planning of the surgical procedure itself. Even in patients with limited prognosis, the first priority is always to achieve clear margins. Due to the widespread use of screening mammography, breast cancers are among the few cancers that are almost always diagnosed in an operable stage and are operated on with curative intention. It is well established that magnetic resonance imaging (MRI) is far superior to mammography (with and without concomitant ultrasound) for mapping the local extent of breast cancer. Accordingly, there is good reason to suggest that a pre-operative breast MRI should be considered an integral part of breast conserving treatment. Still, it is only rarely used in clinical practice. Arguments against its use are: Its high costs, allegedly high number of false positive findings, lack of MR-guided breast biopsy facilities, lack of evidence from randomized prospective trials and, notably, fear of "overtreatment". This paper discusses the reservations against staging MRI and weighs them against its clinical advantages. The point is made that radiologists as well as breast surgeons should be aware of the possibility of overtreatment, i.e. unnecessary mastectomy for very small, "MRI-only" multicentric cancer foci that would indeed be sufficiently treated by radiation therapy. There is a clear need to adapt the guidelines established for treatment of mammography-diagnosed multicentric breast cancer to account for the additional use of MRI for staging. Until these guidelines are available, the management of additional, "MRI-only" diagnosed small multicentric cancer manifestations must be decided on wisely and with caution. MRI for staging may only be done in institutions that can also offer an MR-guided tissue sampling, preferably by MR-guided vacuum assisted biopsy, to provide pre-operative histological proof of lesions visible by breast MRI alone.


Subject(s)
Breast Neoplasms/pathology , Breast Neoplasms/surgery , Magnetic Resonance Imaging/methods , Neoplasm Staging/methods , Patient Selection , Preoperative Care/methods , Female , Humans
19.
AJNR Am J Neuroradiol ; 27(8): 1794-8, 2006 Sep.
Article in English | MEDLINE | ID: mdl-16971638

ABSTRACT

BACKGROUND AND PURPOSE: Current MR imaging criteria for multiple sclerosis (MS) do not specify the magnetic field strength. The aim of this study was to investigate whether different MR imaging field strengths, specifically high-field MR imaging, have an impact on the classification of patients with clinically isolated syndromes suggestive of MS, according to MR imaging and diagnostic criteria. METHODS: In a prospective intraindividual comparative study, we examined 40 patients with clinically isolated syndromes (CIS) consecutively with a 1.5 T and 3T MR imaging system, including axial sections of T2 turbo spin-echo, fluid-attenuated inversion recovery, and T1 spin-echo, before and after injection of gadolinium-diethylene-triaminepentaacetic acid. Constant resolution parameters were used for both field strengths. High-signal-intensity white matter lesions with a size of >3 mm were counted and categorized according to their anatomic location in infratentorial, callosal, juxtacortical, periventricular, and other white matter areas. Assessment of the fulfilled Barkhof MR imaging and McDonald diagnostic criteria was made separately for both field strengths in every patient. RESULTS: Eleven patients fulfilled more MR imaging criteria at 3T. Two of these patients fulfilled the criterion of dissemination in space (DIS) according to the first definition of McDonald criteria, which is based on imaging criteria alone. Another patient had DIS only at 3T, according to the second definition of the McDonald criteria including CSF parameters. CONCLUSION: MR field strength, specifically high-field MR imaging, has a substantial influence on the classification of patients with CIS according to imaging and a mild influence on the classification according diagnostic criteria for MS, leading to consequences for prognostic classification, imaging guidelines, and clinical trials.


Subject(s)
Image Enhancement , Image Processing, Computer-Assisted , Magnetic Resonance Imaging , Multiple Sclerosis/classification , Adolescent , Adult , Artifacts , Brain/pathology , Brain Stem/pathology , Diagnosis, Differential , Female , Humans , Male , Middle Aged , Multiple Sclerosis/diagnosis , Optic Neuritis/classification , Optic Neuritis/diagnosis , Prospective Studies , Reference Values , Sensitivity and Specificity , Spinal Cord/pathology
20.
Rofo ; 178(7): 680-7, 2006 Jul.
Article in German | MEDLINE | ID: mdl-16817122

ABSTRACT

About 10 % of breast cancers are "hereditary", i. e. caused by a pathogenic mutation in one of the "breast and ovarian cancer susceptibility genes" (BRCA). The BRCA genes 1 and 2 identified to date follow an autosomal dominant inheritance pattern. A clustering of breast cancer in a family without a documented mutation and without a recognizable inheritance pattern is usually referred to as "familial cancer". A distinction between hereditary and familial is difficult in the individual case because not all of the genetic mutations that cause breast cancer susceptibility are known and thus amenable to genetic testing. Women who are suspected of or documented as carrying a breast cancer susceptibility gene face a substantially increased lifetime risk of breast (and ovarian) cancer ranging from 60-80 % for breast and up to 40 % for ovarian cancer. In addition, the disease develops at a young age (the personal risk starts increasing at age 25; average age of diagnosis is 40). BRCA-associated breast cancers tend to exhibit histologic and histochemical evidence of aggressive biologic behavior (usually grade 3, receptor negative) with very fast growth rates. In particular BRCA1-associated breast cancer may be indistinguishable from fibroadenomas: they appear as well-defined, roundish, hypoechoic masses with smooth borders, without posterior acoustic shadowing on ultrasound, without associated microcalcifications on mammography, and with strong wash-out phenomenon on breast MRI. This article reviews the different options that exist for the prevention of familial or hereditary breast cancer and the specific difficulties that are associated with the radiological diagnosis of these cancers. Lastly, an overview is given of the current evidence regarding the effectiveness of the different imaging modalities for early diagnosis of familial and hereditary breast cancer.


Subject(s)
Breast Neoplasms/diagnosis , Breast Neoplasms/genetics , Diagnostic Imaging/methods , Mass Screening/methods , Radiology/methods , Risk Assessment/methods , Breast Neoplasms/congenital , Breast Neoplasms/prevention & control , Female , Genetic Predisposition to Disease/genetics , Genetic Predisposition to Disease/prevention & control , Genetic Testing/methods , Humans , Practice Guidelines as Topic , Practice Patterns, Physicians' , Prognosis , Risk Factors
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