Corrigendum to "Improving contrast enhancement in pulmonary CTA: The value of breathing maneuvers" [Eur J Radiol Open 7 (2020) 100280].

[This corrects the article DOI: 10.1016/j.ejro.2020.100280.].

Improving Contrast Enhancement in Pulmonary CTA: The value of breathing maneuvers.

PURPOSE: To investigate contrast dynamics and artifacts associated with different breathing maneuvers during pulmonary computed tomography angiography (pCTA) in a prospective randomized clinical trial. METHOD: Three different breathing maneuvers (inspiration, expiration, Mueller) were randomly assigned to 146 patients receiving pCTA for suspected pulmonary embolism (PE). Contrast enhancement of central and peripheral arteries and imaging quality of lung parenchyma were compared and analyzed. Results were compared by using the analysis of variances (ANOVA) and Kruskal-Wallis-Test. RESULTS: Mean enhancement in the pulmonary trunk was highest during breath-hold in inspiration (293 HU, range 195-460 HU) compared to Mueller (259 HU, range 136-429 HU, p = 0022) and expiration (267 HU, range 115-376 HU). This was similar for the right pulmonary artery (inspiration 289 HU, range 173-454 HU; Mueller 250 HU, range 119-378 HU; p = 0.007; expiration 257 HU, range 114-366 HU; p = 0.032) and left pulmonary artery (inspiration 280.3 HU, range 170-462 HU; Mueller 245 HU, range 111-371 HU; p = 0.016; expiration 252 HU, range 110-371 HU).Delineation of peripheral arteries was significantly better in inspiration vs Mueller (p = 0.006) and expiration (p = 0.049). Assessment of the lung parenchyma was significantly better in inspiration vs Mueller (p = 0.013) or expiration (p < 0.001). CONCLUSIONS: Resting inspiratory position achieved the highest enhancement levels in central and peripheral pulmonary arteries and best image quality of the pulmonary parenchyma in comparison to other breathing maneuvers. It is necessary to train the maneuver prior to the examination in order to avoid deep inspiration with the risk of suboptimal opacification of the pulmonary arteries.

Selective Venous Blood Sampling for Hyperparathyroidism with unclear Localization of the Parathyroid Gland.

Purpose: Evaluation of the benefit of selective venous blood sampling (SVS) for the preoperative identification of parathyroid adenomas with unclear localization in non-invasive diagnostics. Materials and Methods: In a retrospective study, all patients (n = 23) with primary (n = 21) or tertiary (n = 2) hyperparathyroidism were evaluated from 2005 to 2016 at the Hospital Nuremberg-North. These patients all received one (n = 20) or more (n = 3) SVS. 15 patients had one or more previous unsuccessful surgeries (group A), 8 patients received the SVS primarily before the first surgery (group B). Results of SVS were compared with the results of surgery, non-invasive diagnostic procedures and clinical follow up. Results: In 24 out of 26 SVS a significant PTH peak was found. 19 patients underwent surgery after SVS. In 16 of these cases (84 %) the SVS peak was concordant with the intraoperative localization. Thus, SVS of all operated patients had a sensitivity of 94 %. Considering only patients with prior HPT surgery the sensitivity was 89 %. In none of the 26 examinations complications occurred. Conclusion: Our results demonstrate that selective venous blood sampling SVS in cases with unclear imaging of parathyroid adenomas is an effective and low-risk invasive diagnostic method to localize parathyroid adenomas and helps to improve surgical therapy. Key points: • low risk invasive diagnostic procedure to localize parathyroid adenomas• additional step if non-invasive diagnostics are negative or inconclusive• high sensitivity in the detection of parathyroid adenomas Citation Format: • Hader C, Uder M, Loose RWR et al. Selective Venous Blood Sampling for Hyperparathyroidism with unclear Localization of the Parathyroid Gland. Fortschr Röntgenstr 2016; 188: 1144 - 1150.

[Radiation protection in interventional radiology]. / Strahlenschutz in der interventionellen Radiologie.

The application of ionizing radiation in medicine seems to be a safe procedure for patients as well as for occupational exposition to personnel. The developments in interventional radiology with fluoroscopy and dose-intensive interventions require intensified radiation protection. It is recommended that all available tools should be used for this purpose. Besides the options for instruments, x­ray protection at the intervention table must be intensively practiced with lead aprons and mounted lead glass. A special focus on eye protection to prevent cataracts is also recommended. The development of cataracts might no longer be deterministic, as confirmed by new data; therefore, the International Commission on Radiological Protection (ICRP) has lowered the threshold dose value for eyes from 150 mSv/year to 20 mSv/year. Measurements show that the new values can be achieved by applying all X­ray protection measures plus lead-containing eyeglasses.

[Image guiding techniques and navigation for TACE, SIRT and TIPS]. / Bildführungstechniken und Navigation bei TACE, SIRT und TIPS.

CLINICAL/METHODICAL ISSUE: To avoid non-targeted embolization in liver tumors, arteries important for embolization must be detected. In transarterial chemoembolization (TACE) arteries for particle embolization have to be detected and in selective internal radiotherapy (SIRT) extrahepatic arteries which must be protected from embolization have to be detected. In transjugular intrahepatic portosystemic shunt (TIPS) the problem is to achieve an exactly targeted puncture of the portal vein. STANDARD RADIOLOGICAL METHODS: In TACE and SIRT detection of the vessels is performed from various angles by digital subtraction angiography (DSA). In TIPS puncture is guided by ultrasound or performed blindly. METHODICAL INNOVATIONS: Using cone beam CT (CBCT) very small vessels in the liver can be visualized and 2D-3D back projection is able to detect the exact position of the portal vein in TIPS. ACHIEVEMENTS: The use of CBCT and 2D-3D back projection significantly enhances navigation of vessels. PRACTICAL RECOMMENDATIONS: If flat detector technique is available CBCT should be used in TACE and SIRT and 2D-3D navigation needs hardware and software updates.

[Exposition of the operator's eye lens and efficacy of radiation shielding in fluoroscopically guided interventions]. / Exposition der Augenlinse des Untersuchers und Effizienz der Strahlenschutzmittel bei fluoroskopischen Interventionen.

PURPOSE: Efficacy of radiation protection tools for the eye lens dose of the radiologist in fluoroscopic interventions. MATERIALS AND METHODS: A patient phantom was exposed using a fluoroscopic system. Dose measurements were made at the eye location of the radiologist using an ionization chamber. The setting followed typical fluoroscopic interventions. The reduction of scattered radiation by the equipment-mounted shielding (undercouch drapes and overcouch top) was evaluated. The ceiling-suspended lead acrylic glass screen was tested in scattered radiation generated by a slab phantom. The protective properties of different lead glass goggles and lead acrylic visors were evaluated by thermoluminescence measurements on a head phantom in the primary beam. RESULTS: The exposition of the lens of about 110 to 550 µSv during radiologic interventions is only slightly reduced by the undercouch drapes. Applying the top in addition to the drapes reduces the lens dose by a factor of 2 for PA projections. In 25°LAO the dose is reduced by a factor between 1.2 and 5. The highest doses were measured for AP angulations furthermore the efficacy of the equipment-mounted shielding is minimal. The ceiling-suspended lead screen reduced scatter by a factor of about 30. The lead glass goggles and visors reduced the lens dose up to a factor of 8 to 10. Depending on the specific design, the tested models are less effective especially for radiation from lateral with cranial angulation of the beam. Occasionally the visors even caused an increase of dose. CONCLUSION: The exposition of the eye lens can be kept below the new occupational limit recommended by the ICRP if the radiation shielding equipment is used consistently.

[Percutaneous arteriovenous shunting in patients with severe COPD: a new interventional radiological treatment]. / Perkutane arteriovenöse Shuntanlage bei Patienten mit schwerer COPD: eine neue interventionelle radiologische Technik.

PURPOSE: The aim of this study was to evaluate the technical feasibility and safety of a new interventional radiological technique to create a shunt percutanously between the external iliac vein and artery in patients with severe COPD. MATERIALS AND METHODS: 40 patients were included in this multicenter trial. In 38 patients the artery was punctured from the vein using a novel crossing needle. A special delivery system was used to implant a novel nitinol device (ACS, ROX Medical) between the artery and the vein to maintain a 4 mm calibrated and structured fistula between the two vessels. RESULTS: Shunt implantation was successful in 38 patients. The perfused arteriovenous shunts could be well documented in DSA and the diameter was measured between 3 and 4 mm in all cases. Peri-interventional non-flow-limiting dissection of the iliac artery occurred in one patient. Post-interventional venous bleeding in two patients was treated successfully by local compression. In one patient a peripheral artery thrombembolism was successfully treated by thrombolysis. CONCLUSION: The new interventional radiological technique to create an arteriovenous shunt in the iliac vessels presented in this study has proven to be feasible and safe.

[Periinterventional cone-beam-CT: application at transarterial chemoembolization of liver tumors]. / Periinterventionelle Cone-Beam-CT: Anwendung bei transarterieller Chemoembolisation von Lebertumoren.

Periinterventional Cone-Beam CT (CBCT) today is a valuable tool in complex radiological interventions. Only little experience exists about CBCT in transarterial chemoembolisations (TACE) of liver tumors. 25 patients underwent periinterventional CBCT. We used a C-arc DSA with 30 × 40 cm flat panel detector. Image data with axial, coronal and 3D-reconstruction were acquired by 217° rotation in 8 seconds. In all 25 cases CBCT had an influence on the TACE regarding the decision which vessels to catheterize, the amount of retention of the embolisation agent or an abort because of insufficient vascularisation. In comparison with DSA alone, CBCT allows a better visualisation of tumour vessels, simplifies selective catheterisation, the decision whether an embolisation is possible and enables a good visualisation of Lipiodol retention. Hence, CBCT is a helpful periinterventional tool but cannot substitute CT and MRI in follow up.

[Medical radiation exposure and justification at a large teaching hospital: comparison of radiation-related and disease-related risks]. / Medizinische Strahlenexposition und ihre Rechtfertigung an einem Grossklinikum: Vergleich von strahlungs- und krankheitsbedingtem Risiko.

PURPOSE: The medical X-ray exposure was determined in a 2400-bed hospital. The radiation-related risk was compared with the severity of disease (ICD) to verify the justification for X-ray procedures. A model to estimate radiation and disease-related "loss of lifetime" was applied. MATERIALS AND METHODS: X-ray exposure from radiography, fluoroscopy and CT was determined for diagnostic and interventional procedures during one hospital stay of 403 patients (0.5 % of all 80 000 patients/year). CTDI and DLP in CT, DAP in fluoroscopy or SED in radiography were used to calculate the effective dose (ED). The disease and radiation-related risk were compared with a simple "loss of lifetime" model. RESULTS: The mean age of all patients was 60. Only a subgroup of 170 patients (42 %) with a mean age of 67.6 had one or more X-ray procedures. The average ED of these exposed patients was 5.12 mSv. 14.4 % CT examinations had a dose contribution of 52.5 % followed by 5.3 % radiology and cardiology procedures at 37.2 %. 90 % of ED was applied to only 44 patients (11 %) and 50 % of ED was applied to only 10 patients (2.5 %) with a mean age of 71.2. 4 of these 10 patients had malignant tumors, the other 6 suffered from pulmonary embolism, pneumonia, stent-graft infection, CAD, Crohn's disease and severe hypertension. The ratio of disease vs. radiation-related risk was between 2.1 : 1 and 1800 : 1. CONCLUSION: In this study referral for justified X-ray procedures in a large hospital with high level medical care offers a significant patient benefit.

[Clinical results with a detachable temporary vena cava filter]. / Erfahrungen mit einem abwerfbaren temporären Vena cava Filter.

PURPOSE: Evaluation of the feasibility of implantation and explantation and evaluation of the efficacy of a detachable and retrievable temporary vena cava filter. MATERIALS AND METHOD: The temporary vena cava filter "OptEase" (Cordis) is a nitinol filter derived from the "TrapEase" (Cordis) permanent filter, which is implantable transjugularly or transfemorally. In contrast to other temporary filters, this type can be detached and is not fixed on a catheter during implantation. Therefore, it is usable as a temporary as well as a permanent filter which can be retrieved up to 12 days after detachment with a special catheter using the loop technique. The "OptEase" filter was implanted in 11 patients ranging in age from 19 to 82 (mean age 30 years). In 10 patients the filter was transfemorally implanted and explanted. In 1 patient implantation was performed transjugularly prior to surgery and explantation was performed transfemorally after surgery. All patients had a deep vein thrombosis or iliac vein thrombosis. In 3 patients the filter was implanted prior to surgery. In 2 patients pulmonary embolism was identified. In 5 patients the filter was implanted prophylactically because of deep vein thrombosis according to interdisciplinary diagnosis. RESULTS: No pulmonary embolism occurred during implantation. All filters were able to be retrieved without complications using the loop technique on the 6th, 8th, 12th and 13th day. No captured thrombus material was in the filter. CONCLUSIONS: This new vena cava filter type is an easily implantable and retrievable system. Since this filter type is detachable without a need for venous access during implantation, there are no sterility problems. The filter can be left in the vena cava as a permanent system if explantation is not indicated.

[Ultrasound-guided puncture of the subclavian vein to implant central venous ports]. / Sonographisch gesteuerte Punktion der Vena subclavia vor radiologischer Portimplantation.

PURPOSE: To assess the safety and efficacy of ultrasound guided puncture of the subclavian vein instead of blind puncture or surgical procedure. The advantages compared with implantation of brachial ports are demonstrated. PATIENTS AND METHODS: In 41 oncologic patients the subclavian vein was punctured by ultrasound guidance in order to implant a port (34 left side, 7 right side). The study included 21 women and 20 men (range 34 - 79, mean 61 years). Imaging of the subclavian vein was performed with a 7,5 MHz linear ultrasound probe in B-mode and in colour doppler mode. Puncture was performed under ultrasound control (18 G, 45 mm needle when skin-vessel distance was < 3 cm, 19 G, 75 mm needle when skin-vessel distance was > 3 cm). In 27 patients a Bardport was implanted, in 14 patients a Vitalport (Cook). In three patients surgical port implantation failed. One of these patients had a partial thrombosis of the subclavian vein. RESULTS: Technical success was 100 %. In one patient we first punctured the subclavian artery at the beginning of our series without any complication. All port systems could be implanted. There was one haematoma in the port pocket without any effect to the port function. In the three surgical patients subclavian vein puncture and portimplantation was successful. CONCLUSION: Ultrasound guided puncture of the subclavian vein and port implantation by radiologists is a save procedure. A low risk approach to the subclavian vein is possible at any location. The long approach through the cubital vein with brachial port implantation is not necessary.

[Portal vein resection in the framework of surgical therapy of pancreatic head carcinoma: clarification of indication by improved preoperative diagnostic procedures?]. / Pfortaderresektion im Rahmen der chirurgischen Therapie von Pankreaskopfcarcinomen--verbesserte präoperative Diagnostik als Entscheidungshilfe bei der Indikationsstellung?

Tumor invasion of the portal vein by ductal adenocarcinoma of the pancreatic head is classically known as a criterion for inoperability. Despite improvement in operation techniques for portal vein resection during Whipple's procedure and acceptable mortality and morbidity, in the case of uncertain tumor infiltration vascular resection cannot be recommended in general. The problem is the preoperative detection of tumor infiltration of the portal vein. Often the surgeon is confronted with unsuspected macroscopic portal vein infiltration or tumor adhesion during the operation. Between 1986 and 1995 105 patients underwent Whipple's procedure for ductal adenocarcinoma of the pancreatic head in our department. In eight of these cases partial portal vein resection was performed because of macroscopic tumor infiltration or tumor adhesion. In all eight cases the preoperative diagnostic procedures with CT and portography did not show any suspicion of tumor infiltration. In four of the eight cases histological tumor infiltration of all vascular layers was found. In the others we found no or only adventitial tumor invasion. The patients without tumor infiltration of the portal vein showed a survival time after surgery of 27.78 months in contrast to 6.67 months in the group with histologically proven tumor infiltration. Endovascular, intraportal ultrasound (IPEUS), a new diagnostic procedure, can give helpful information regarding portal vein involvement. Although the IPEUS is not a standard diagnostic procedure it was shown to detect portal vein infiltration with high sensitivity and specificity. Our results indicate that in such cases where portal vein infiltration has been excluded by IPEUS, patients with macroscopic tumor adhesion do benefit from partial portal vein resection.

Intra-arterial Doppler flowmetry in the superficial femoral artery following angioplasty.

The aim of the study was to assess the diagnostic value of an intravascular Doppler guidewire in patients with peripheral percutaneous angioplasty (PTA). The prognostic value was also evaluated. Measurements were done prior and following angioplasty in 22 patients with peripheral arterial occlusive disease. As additional therapy, stent insertion and peripheral (Aa. poplitea Tll/tibial) angioplasty was performed (4 patients per group). For stress testing, adenosinetriphosphate (ATP) was given intra-arterially. Follow-up was performed by angiography, colour-coded duplex ultrasound or judged by unequivocal clinical stage at follow-up to 13 months. Average (APV) and maximal peak velocity (MPV) increased following PTA, after additional treatment (peripheral PTA or stent), and after intra-arterial application of a vasodilator. Patients with peripheral lesions had markedly lower velocities prior treatment and following PTA after vasodilatation. Following peripheral PTA, the values were similar to the patients with PTA alone. Velocities after stenting were markedly increased in the stress condition. Of the 22 patients, 7 had a recurrent disease. The latter patients had higher velocities at rest prior to and following PTA. In stented lesions higher velocities seem to be linked with a worse outcome. The ratio between velocity prior to and after the application of the vasodilator seems to be of diagnostic importance. A ratio of 1.9 or more was of positive prognostic value. The Doppler guidewire is a practical and valuable tool in assessing technical success after angioplasty of peripheral lesions, critical or morphologically worse lesions. In our study the decision for stent application was made on the morphological image; however, increased velocity and changes in phasicity substantiated our decisions. Increased ratios prior to and after vasodilation (flow reserve) are of prognostic value and therefore suitable as indication for stent placement or tibial angioplasty.

Therapy for biliary stenoses and occlusions with use of three different metallic stents: single-center experience.

PURPOSE: The authors report their experience with three different metallic stents for the treatment of biliary obstructions during a 6.5-year period (between February 1989 and June 1995). MATERIALS AND METHODS: In an uncontrolled, nonrandomized, and prospective study, 168 patients with obstructive jaundice underwent transhepatic placement of metallic stents. Patients were excluded if they were deemed too ill for intervention or had incorrectable coagulopathy. Those patients undergoing external and/or intraluminal radiation therapy, and patients in whom an internal-external catheter was kept in place after insertion of a stent were not included. Inoperable malignant disease was diagnosed in 157 patients (93.5%). Eleven patients presented with a benign biliary stricture that could not be managed by means of angioplasty. One hundred fifty-five Wallstents were placed in 122 patients, 65 tantalum Strecker stents were placed in 30 patients, and 18 Memotherm stents were placed in 16 patients. The patients were followed until September 1996 or until death. RESULTS: Regarding malignant obstruction, the 30-day mortality rate was 10.7% without any procedure-related death, and overall survival rates after 100 and 200 days were 63% and 22%, respectively. Regarding benign stricture, eight of 11 patients were alive after a median follow-up of 50.6 months without any 30-day mortality. Major complications occurred in 16 patients (10.2%) who had malignancy, and in two patients (18.2%) with benign biliary disease. The cumulative patency rate in malignant obstructions was significantly higher for the Wallstent than for the Memotherm stent (P < .05) and nonsignificantly higher for the Wallstent than for the tantalum Strecker stent (P > .05). Reintervention due to recurrent obstructive jaundice was necessary in 28 patients (17.8%) with malignancy, and in six patients (54.5%) with benign stricture. CONCLUSIONS: The Wallstent is the most effective in achieving long-term palliation in patients with malignant obstructive jaundice. The treatment of benign biliary strictures with metallic stents is associated with a low long-term patency rate.

Transjugular intrahepatic portosystemic shunting (TIPS) with balloon-expandable and self-expanding stents: technical and clinical aspects after 3 1/2 years' experience.

PURPOSE: To evaluate prospectively our experience with transjugular intrahepatic portosystemic shunt (TIPS) using four different metallic stents. METHODS: Between November 1991 and April 1995, 57 patients (41 men and 16 women; age 35-72 years, mean 54 years) underwent the TIPS procedure. Techniques for portal vein localization before and during TIPS were fluoroscopy, computed tomography (CT) studies, wedged hepatic venography, arterial portography, and ultrasound. After predilation we deployed balloon-expandable (n = 48) and self-expanding (n = 45) metallic stents. Fifteen patients underwent variceal embolization. Initial follow-up angiograms (mean 6.9 months, range 3-24 months) were obtained in 39 of these patients. RESULTS: Fifty-three patients (93%) had successful TIPS placement. The mean decrease in portal pressure was 42.7%. Besides fluoroscopy, the most helpful techniques for portal vein localization were venography and CT. Residual stenosis (n = 1) and late shortening (n = 4) of Wallstents resulted in shunt dysfunction. The technical problems encountered with the Palmaz stent resulted from its lack of flexibility. We combined balloon-expandable and self-expanding stents in 12 patients. The 30-day and late follow-up (mean 11.9 months) percutaneous reintervention rates were 11.3% and 64.2%, respectively. There were no clinically significant complications related to the TIPS insertions. CONCLUSION: An ideal stent does not exist for TIPS, and the authors recommend combining a Palmaz stent with a flexible self-expanding stent.

[Indications and outcome effectiveness of transpopliteal angioplasty]. / Indikation und Erfolg der retrograden transpoplitealen Angioplastie.

PURPOSE: In this retrospective study, the results following angioplasty by the retrograde transpopliteal approach were evaluated to confirm the indications of this technique. PATIENTS AND METHODS: 34 patients were evaluated. Of these 28 were male and 6 were female. Differences to a normal group of patients planned to have angioplasty are the different location of the puncture and on extremely negative selection. RESULTS: Technical success was observed in 84%. A long-term patency ratio of 0.53 was achieved after 30 month. No complications relevant to the therapy were observed. CONCLUSIONS: The transpopliteal approach is a safe and efficient alternative to femoral puncture if the latter is impossible. Compared to the crossover-technique, mechanical considerations favor this technique.

[Transjugular intrahepatic portasystemic shunt. A new therapeutic method in portal hypertension]. / Transjugulaer intrahepatisk portosystemisk shunt. En ny behandlingsmetode ved portal hypertensjon.

Over the last three years, 53 patients underwent transjugular portosystemic shunting (TIPS). 49 patients were treated successfully (92.5%). Procedure-related morbidity (intention to treat) was seen in 11 patients (20.8%): encephalopathy (n = 5), sepsis (n = 3), right heart failure (n = 2) and progressive liver failure (n = 1). 30-day mortality rate was 13.2% (7/53); five of these patients were in stage Child-Pugh C, one patient in stage B, and one patient had a known coronary heart disease. 30-day rebleeding rate was 6.1% (3/49), but all these patients could be retreated successfully by radiological methods (PTA, embolisation, thrombolysis). Angiographic follow-up (mean six months) of 35 patients detected 30 (85.7%) haemodynamic relevant obstructions (stenosis of stent: n = 4, stenosis of hepatic vein: n = 15, stenosis of stent and hepatic vein: n = 5, occlusion of TIPS-shunt: n = 6). Secondary patency rate following percutaneous reintervention was 91.3%. All rebleedings in the follow-up (n = 7) were treated successfully by TIPS-revision. Five out of 12 patients (41.7%) with refractory ascites were treated successfully by TIPS (complete resolution of ascites after three months: n = 4, significant reduction of ascites: n = 1). We conclude that transjugular portosystemic shunt is an effective way of treating portal hypertension, but there is a need to develop methods to prevent the high incidence of shunt stenosis.