Radiation protection in CT-guided interventions: does real-time dose visualisation lead to a reduction in radiation dose to participating radiologists? A single-centre evaluation.

AIM: To evaluate if real-time dose visualisation during computed tomography (CT)-guided interventions leads to a reduction in radiation dose to participating radiologists. MATERIALS AND METHODS: The individual radiation dose radiologists are exposed to during CT interventions was measured using dedicated dosimeters (RaySafe i2-system, Unfors RaySafe GmbH, Billdal, Sweden) worn over the usual radiation protective apron. Initially, only the total radiation dose was measured, without visualisation (control group). In the following study period, the radiation dose was shown to participants on a live screen in real-time (experimental group). In both groups, the dose was recorded in 1-second intervals. The results collected were evaluated by comparison using descriptive statistics and mixed-effect models. In particular, the variables experience, gender, role, and position during the intervention were analysed. RESULTS: In total, 517 measurements of 304 interventions (n=249 with and n=268 without live screen) performed by 29 radiologists acting as interventionalists or assistants were analysed. All CT-guided interventions were performed percutaneously, the majority of which (n=280) were microwave ablations (MWA). Radiation doses in the group without visualisation were comparable with usual dose rates for the corresponding intervention type. The mean total radiation dose was reduced by 58.1% (11.6 versus 4.86 µSv) in the experimental group (p=0.034). The highest reduction of 78.5% (15.55 versus 3.35 µSv) was observed in radiologists with the role of assistant (p=0.002). Sub-analysis showed significant dose reduction (p<0.0001) for the use of live screen in general; considering all variables, the role "assistant" alone had a statistically significant influence (p=0.002). CONCLUSION: The real-time visualisation of active radiation dose during CT interventions leads to a relevant reduction in radiation dose to participating radiologists.

Comparison of contrast-enhanced videofluoroscopy to unenhanced dynamic MRI in minor patients following surgical correction of velopharyngeal dysfunction.

OBJECTIVES: To compare dynamic magnetic resonance imaging (MRI) with videofluoroscopy (VFS) regarding image quality and assessment of gap size between soft palate (SP) and posterior pharyngeal wall (PPW) in children and adolescents following surgical correction of velopharyngeal dysfunction (VPD). METHODS: Twenty-one patients undergoing unenhanced 3-T MRI and contrast-enhanced VFS were included in this IRB-approved prospective study. The MRI scan protocol comprised refocused gradient-echo sequences in transverse and sagittal planes during speech, with TE 1.97 ms, TR 3.95 ms, flip angle 8°, matrix size 128 × 128, and 5-mm slice thickness. Radial k-space sampling and sliding window reconstruction were used to achieve an image acquisition rate of 28 frames per second (fps). VFS with 30 fps was similarly performed in both planes. Closure of the velopharyngeal port during phonation was evaluated by two experienced radiologists. RESULTS: Eleven (52.4%) patients displayed a complete closure, whereas ten (47.6%) patients showed a post-operative gap during speech. VFS and MRI equally identified the cases with persistent or recurrent VPD. Differences in SP-PPW distance between VFS (3.9 ± 1.6 mm) and MRI (4.1 ± 1.5 mm) were not statistically significant (p = 0.5). The subjective overall image quality of MRI was rated inferior (p < 0.001) compared with VFS, with almost perfect inter-rater agreement (κ = 0.90). The presence of susceptibility artifacts did not limit anatomical measurements. CONCLUSION: Dynamic MRI is equally reliable as VFS to assess persistent or recurrent inadequate velum closure in patients following surgical treatment of VPD. KEY POINTS: • Unenhanced 3-T dynamic MRI and contrast-enhanced videofluoroscopy are equally useful for the identification of patients with incomplete velopharyngeal closure during speech. • MRI using refocused gradient-echo acquisition with radial k-space sampling and sliding window reconstruction generates diagnostic images with 28 frames per second. • MRI can offer a radiation-free alternative to currently established videofluoroscopy for young patients.

CT-guided percutaneous biopsy of suspect pancreatic lesions: radiological and clinical outcome.

AIM: To evaluate the clinical utility of computed tomography (CT)-guided percutaneous biopsies of suspect pancreatic lesions regarding safety, efficiency, radiation dose, intervention time, diagnostic yield, and complications. MATERIALS AND METHODS: Between 2015 and 2018, 48 patients (18 female, 30 male; mean age: 64.2 years) with suspect pancreatic lesions underwent CT-guided percutaneous biopsy. Ultrasound-guided biopsy of all lesions was not possible or without any result. CT-guided interventions were compared according to the following intervention parameters: radiation dose, procedure duration, number of needle correction scans. Evaluation criteria included technical success as well as major and minor complications according to the Society of Interventional Radiology. RESULTS: Biopsies were performed successfully in 100% of patients. No major side effects occurred during intervention. As a minor complication, 29.2% showed focal haemorrhage. Seventy-seven percent of lesions had a malignant appearance, and benign inflammatory lesions were found in 23%. The mean size of the target lesions was 2.9 cm (range: 0.7-2.3 cm). The mean target access path within the patient was 8 cm (range: 3-14 cm). The duration to completion was 12 minutes (range: 3 minutes 30 seconds to 30 minutes). The dose-length product of the intervention was 89.5 mGy·cm (range: 11-350 mGy·cm). The average number needle correction scans was 31.1 (range: 6-36). CONCLUSION: CT-guided biopsy of suspect pancreatic lesions is an efficient and safe method. It can be performed within short intervention times and low radiation exposure for differentiation of unclear lesions.

Minimally invasive screw fixation of fractures in the thoracic spine: CT-controlled pre-surgical guidewire implantation in routine clinical practice.

AIM: To evaluate the feasibility and accuracy of minimally invasive, transpedicular screw placement in cervicothoracic fractures with the help of computed tomography (CT)-controlled guidewires. MATERIALS AND METHODS: Two hundred and ninety-three guidewires were inserted in 35 patients (42.9±21.2 years) under CT fluoroscopy (286 thoracic, seven cervical). There were 28 traumatic cases, three pathological fractures, three fractures due to infectious infiltrations, and one osteoporotic fracture. In 151 pedicles, screw placement was performed in the CT room. CT images were reviewed regarding accuracy and cortical violations using the popular 2 mm increment deviation classification of Gertzbein and Robbins. RESULTS: Guidewire implantation resulted in only 28 cortical contacts. Minor encroachments of the pedicle wall by inserted screws occurred in 39.1% (59 of 151) and in 23.8% if taking unavoidable encroachments into account (30 of 59). Pedicular isthmus width correlated to cortical guidewire contacts (r=-0.449; p=0.077) and pedicle violations (all graded "A") by the inserted screws (r=-0.581; p=0.049). Total procedural duration was 138.6±44.2 minutes, representing 14.5±11.6 minutes for each pedicle, while showing a significant correlation against higher vertebral levels (r=-0.849; p=0.0002) and the occurrence of pedicle violations (r=-0.641; p=0.027). CONCLUSIONS: The treatment of vertebral fractures with a guidewire-based pedicle screw insertion technique under CT imaging results in very high accuracy and a low complication rate.

Radiation dose and quickness of needle CT-interventions using a laser navigation system (LNS) compared with conventional method.

PURPOSE: The aim of this study was to analyse the radiation dose and quickness of needle interventions using a Laser Navigation System (LNS-group) compared with conventional method (control-group). MATERIALS AND METHODS: In this prospective, randomized, comparative study 58 patients (19 females, 39 males; mean age, 62.9 years) were punctured either with LNS (n=29) or with conventional method with a skin mark of the puncture site (n=29). In the LNS method the puncture site was marked with laser without additional CT. Thoracic and abdominal intervention was performed in 30 and 28 patients, respectively. Radiation dose and time of the procedures were analysed. Statistical significance was calculated according to the Mann-Whitney-U-test. RESULTS: Mean target access path in the patients of the LNS group was 6.0 cm (range, 3.0-10.1cm) and in the control group 6.0 cm (range, 1.0-10.3 cm). Time duration of complete intervention in the LNS group was 20:25 min (range, 07:00-34:00 min) and in the control group 28:00 min (range, 13:00-51:00 min). The dose-length-product (DLP) of intervention scan of the LNS group was 42.3 mGy cm (range, 10-125 mGy cm), and of the control group 59.7 mGy cm (range, 25-176.42 mGy cm). CONCLUSION: Using the LNS for CT-guided interventions results in faster intervention time with a lower dose.

The health technology assessment of the compulsory accident insurance scheme of hand transplantation in Switzerland.

UNLABELLED: Recently the decision-making committee of the compulsory Swiss accident insurance scheme needed to make a basic decision as to whether to fund hand transplantation under that scheme or not. A Health Technology Assessment was commissioned to inform decision-making and gain experience with applicability of the method. The following were main findings from various domains. Compared with prosthesis fitting, the outcome of hand transplantation is satisfactory for function and sensibility. Complications due to immunosuppression are frequent, sometimes severe and potentially life-shortening. The direct medical costs over the entire life span calculated for a 35-year-old unilaterally amputated base case patient were CHF 528,600 (EUR 438,500) higher than for a prosthesis. There are challenging ethical, legal and organizational issues. The committee decided not to reimburse hand transplantation for ethical reasons. The Health Technology Assessment has been shown to be a useful tool for decision-making in the context of Swiss accident insurance. LEVEL OF EVIDENCE: IV.

MR-guided laser-induced thermotherapy (LITT) in patients with liver metastases of uveal melanoma.

PURPOSE: Evaluation of the local tumour control rate and survival data for magnetic resonance (MR) imaging-guided laser ablation of uveal malignant melanoma liver metastases by using laser-induced interstitial thermotherapy (LITT). MATERIALS AND METHODS: The LITT was performed in 18 patients with liver metastases (n = 44) from uveal malignant melanoma. All patients tolerated this intervention well. With the Kaplan-Meier method, the survival rates were calculated. Indications for the procedure were defined for patients with no more than five metastases, none of which were larger than 5 cm in diameter: The Indication for LITT treatment were recurrent liver metastases after partial liver resection (22%), locally non-resectable tumours (17%) or metastases in both liver lobes (61%). RESULTS: The mean survival rate for all treated patients was 3.6 years (95% CI: 2.19, 5.06). We started the calculation on the date of diagnosis of the metastases treated with LITT. The median survival was 1.83 years; 1-year survival, 88%; 3-year survival 47%, 5-year survival 17%. Calculated after the first LITT treatment the median survival was 2.8 years (95% CI: 1.0, 5.0). 10 patients were treated by transarterial chemoembolization before LITT. CONCLUSION: MR-guided LITT treatment shows a high local tumour control and survival rates in patients with liver metastases of uveal malignant melanoma.

Hepatic arterial infusion with irinotecan in patients with liver metastases of colorectal cancer: results of an extended phase I study.

BACKGROUND: To define the maximum tolerated dose (MTD) tolerability and efficacy of intra-arterial chemotherapy with irinotecan in patients with liver metastases of colorectal carcinoma (CRC). METHODS: Superselective intra-arterial irinotecan was applied on days 1, 14, 28 and 42. The initial dose was 140 mg/m² with escalation in the subsequent patient group to 160 mg/m². The final protocol toxicity evaluation was 260 mg/m². Patients required histologically proven disease and adequate bone marrow, liver and renal function, no extrahepatic metastasis and a life expectancy >12 weeks. results: Thirty-three patients were enrolled (median age 65, range 49-78 years). On dose level VI (240 mg/m²), 1 case of dose-limiting toxicity (DLT) (granulocytopenia) was observed, leading to an enlarged cohort of 6 patients. As no additional DLT was detected on this level, an escalation to level VII was performed. On the dose level of 260 mg/m², irinotecan DLTs were observed, resulting in the termination of escalation and the declaration of dose level VI as MTD. Imaging follow-up with Response Evaluation Criteria in Solid Tumors (RECIST) criteria revealed a complete response in 1 patient, stable disease in 31 patients, and progressed disease in 1 patient. The median time to progression was 4.7 months, the median overall survival 15.6 months. CONCLUSION: The method of intra-arterial chemotherapy with irinotecan is well tolerated and shows promising local response rates in liver metastases of CRC.

Intraoperative PEEP-ventilation during PMMA-injection for augmented pedicle screws: improvement of leakage rate in spinal surgery.

BACKGROUND: Within the last two decades the use of polymethylmethacrylate (PMMA) in the treatment of osteoporotic vertebral fractures has been established widely. Several techniques of cement application in spinal surgery have been described. Besides classical vertebroplasty, kyphoplasty and related techniques that reinforce stability of the fractured vertebral body itself, augmentation of pedicle screws became an issue in the past 10 years. Aim of this technique is strengthening of the implant-bone-interface and the prevention of loosening and failure of posterior instrumentation in limited bone quality due to osteoporosis. PMMA use in spinal surgery always bears the risk of cement leakage and cement embolism. There are only few publications dealing with cement leakage in pedicle screw augmentation. We examined our cohort concerning incidence and type of leakage in comparison to the literature. In particular, we evaluated a possible role of intrathoracic pressure during cementation procedure. PATIENTS AND METHODS: In this retrospective study 42 patients were included. Mean age was 74 (57-89) years. 311 fenestrated, augmented screws were analyzed postoperatively concerning leakage and subsequent pulmonary embolism of cement particles. Overall, there was a leakage rate of 38.3 %, and 28.6 % of patients showed pulmonary embolism of PMMA. During surgery, patients were in part ventilated with a positive end-expiratory pressure (PEEP) of 15 cmH2O during cement injection. These individuals showed significantly less leakage locally as well as less PMMA-emboli in the pulmonary circulation in contrast to patients ventilated without increased PEEP. CONCLUSION: PEEP elevation during administration of PMMA via fenestrated pedicle screws is reducing the leakage rate in spinal surgery. These beneficial effects warrant further evaluation in prospective studies.

First human study in treatment of unresectable liver metastases from colorectal cancer with irinotecan-loaded beads (DEBIRI).

The objective of this pilot clinical study was to assess the safety, technical feasibility, pharmacokinetic (PK) profile and tumour response of DC Bead™ with irinotecan (DEBIRI™) delivered by intra-arterial embolisation for the treatment of metastatic colorectal cancer. Eleven patients with unresectable liver metastases from CRC, tumour burden <30% of liver volume, adequate haematological, liver and renal function, performance status of <2 were included in this study. Patients received up to 4 sessions of TACE with DEBIRI at 3-week intervals. Feasibility of the procedure, safety and tumour response were assessed after each cycle. PK was measured after the first cycle. Patients were followed up to 24 weeks. Only mild to moderate adverse events were observed. DEBIRI is a technically feasibile procedure; no technical complications were observed. Average Cmax for irinotecan and SN-38 was 194 ng/ml and 16.7 ng/ml, respectively, with average t½ of 4.6 h and 12.4 h following administration of DEBIRI. Best overall response during the study showed disease control in 9 patients (2 patients with partial response and 7 with stable disease, overall response rate of 18%). Our study shows that transarterial chemoembolisation with irinotecan-loaded DC beads (DEBIRI) is safe, technically feasible and effective with a good PK profile.

[Radiological diagnosis and intervention of cholangiocarcinomas (CC)]. / Radiologische Diagnostik und Intervention von Cholangiokarzinomen (CC).

To present current data on diagnosis, indication and different therapy options in patients with cholangiocarcinoma (CC) based on an analysis of the current literature and clinical experience. The diagnostic routine includes laboratory investigations with parameters of cholestasis and also serum tumor markers CA19 - 9 and CEA. After ultrasound for clarifying a tumor and/or dilated bile ducts, contrast-enhanced magnetic resonance imaging (MRI) should be performed with magnetic resonance cholangiography (MRCP). The accuracy (positive predictive value) for diagnosing a CC is 37-84% (depending on the location) for ultrasound, 79-94% for computed tomography (CT), and 95% for MRI and MRCP. An endoscopic retrograde cholangiography (ERCP) can then be planned, especially if biliary drainage or cytological or histological specimen sampling is intended. A curative approach can be achieved by surgical resection, rarely by liver transplantation. However, many patients are not eligible for surgery. In addition to systemic chemotherapy, locoregional therapies such as transarterial chemoembolization (TACE), hepatic arterial infusion (HAI)--also known as chemoperfusion--, drug eluting beads-therapy (DEB) as well as thermoablative procedures, such as laser-induced thermotherapy (LITT), microwave ablation (MWA) and radiofrequency ablation (RFA) can be provided with a palliative intention.

[Robot-assisted biopsies in a high-field MRI system - first clinical results]. / Roboterunterstützte Punktion in einem Hochfeld-Kernspintomografen - erste klinische Ergebnisse.

PURPOSE: The purpose of this study was to examine the clinical use of MR-guided biopsies in patients with suspicious lesions using a new MR-compatible assistance system in a high-field MR system. MATERIALS AND METHODS: Six patients with suspicious focal lesions in various anatomic regions underwent percutanous biopsy in a high-field MR system (1.5 T, Magnetom Espree, Siemens) using a new MR-compatible assistance system (Innomotion). The procedures were planned and guided using T 1-weighted FLASH and TrueFISP sequences. A servopneumatic drive then moved the guiding arm automatically to the insertion point. An MRI compatible 15G biopsy system (Somatex) was introduced by a physician guided by the needle holder and multiple biopsies were performed using the coaxial technique. The feasibility, duration of the intervention and biopsy findings were analyzed. RESULTS: The proposed new system allows accurate punctures in a high-field MR system. The assistance device did not interfere with the image quality, and guided the needle virtually exactly as planned. Histological examination could be conducted on every patient. The lesion was malignant in four cases, and an infectious etiology was diagnosed for the two remaining lesions. Regarding the differentiation of anatomical and pathological structures and position monitoring of the insertion needle, TrueFISP images are to be given preference. The average intervention time was 41 minutes. Lesions up to 15.4 cm beneath the skin surface were punctured. CONCLUSION: The proposed MR-guided assistance system can be successfully utilized in a high-field MR system for accurate punctures of even deep lesions in various anatomic regions.

Differentiation between benign and malignant adrenal mass using contrast-enhanced ultrasound.

PURPOSE: Adrenal masses can be detected by ultrasound with high sensitivity and specificity. The aim of the present study was to evaluate CEUS in a large patient population using CEUS patterns identified in a previous pilot study. MATERIALS AND METHODS: 116 adrenal masses were evaluated by ultrasound, including CEUS with the contrast agent Sonovue®. The dynamic of contrast enhancement (CE) was analyzed using time-intensity curves. The time of the first CE in the adrenal mass was used to define four CEUS patterns: pattern I = early arterial CE, pattern II = arterial CE, pattern III = late CE, pattern IV = no CE. In addition, all patients received CT/MRI and hormonal testing. In suspicious cases biopsy or adrenalectomy was performed. RESULTS: CEUS patterns I&II were seen in all patients with primary or secondary malignant lesions of the adrenal gland (n = 16). The sensitivity and specificity of CEUS for the diagnosis of malignant adrenal mass were 100 % (CI [75;100]) and 67 % (CI [56;75]), respectively. Overall histology was available as a reference method for 40 adrenal masses. In 68 % of histologically diagnosed adrenal masses, MRI/CT and CEUS were congruent concerning the characterization of malignant versus benign adrenal mass. CONCLUSION: Contrast-enhanced ultrasound may be a useful method in the diagnostic work-up of adrenal mass with excellent sensitivity for the diagnosis of malignancy.

[Chemoperfusion and embolization in the treatment of liver metastases]. / Chemoperfusion und -embolisation von Lebermetastasen.

Presentation of techniques and procedures for regional chemotherapy in the treatment of unresectable liver metastases from different primary tumors as a modality of interdisciplinary therapy management. Such transarterial therapy methods include hepatic arterial infusion (HAI), transarterial chemoembolization (TACE), chemoembolization with cytostatic-loaded microspheres (DEBs), transarterial embolization (TAE) and selective internal radiation therapy (SIRT). Regional chemotherapy procedures in the treatment of liver metastases represent a minimally invasive treatment option that can be successfully combined with surgical resection and/or radiofrequency (RFA), laser-induced thermotherapy (LITT), microwave ablation (MWA). These procedures allow optimization of the local control rate with strictly intrahepatic processes and lead to increased survival rates without any quality of life restriction.

[Abnormal x-ray finding after central venous catheterization]. / Radiologisch auffälliger Befund nach Anlage eines zentralen Venenkatheters.

Central venous catheter placement can cause a variety of complications, such as catheter fracture, loss of the guide wire and embolization. In the case reported a large bore central venous catheter was used in a 32-year-old patient undergoing surgery for vertebral body fracture of the thoracic spine. After a complication-free surgical procedure the post-operative x-ray showed an abnormal finding. A piece of the guide wire was suspected to have been left in the patient. However, this possibility could be ruled out by the anesthesiologist who inserted the catheter. With an additional x-ray and CT scan of an identical catheter it could then be demonstrated that the abnormal finding was caused by polyurethane pins which are integrated in the catheter.

[MR-guided interventions of the prostate gland: a literature review]. / Aktueller Stand der MR-gesteuerten Prostata-Interventionen.

In recent years MR imaging has played an increasingly important role in the diagnosis and treatment of prostate cancer. MR imaging of the prostate allows clear delineation of the anatomic structures and prostate tumors using T 2-weighted images combined with spectroscopy and dynamic examinations. The advantages of MRI make it possible to perform interventions, like biopsies, brachytherapy or different local therapies of the prostate gland. MRI robotic assistance will improve the accuracy of the interventions. Due to the advantages of MR imaging, MR-guided prostate interventions will play a greater role in the future.

[Retrospective 5-year analysis of MR-guided biopsies in a low-field MR system]. / Retrospektive Analyse der 5-Jahres-Ergebnisse von MRT-gesteuerten Biopsien im Niederfeldsystem.

PURPOSE: The purpose of this study was to evaluate the safety and clinical value of MR-guided biopsies in an open 0.2 T low-field system. MATERIALS AND METHODS: A total of 322 patients with suspicious lesions of different body regions were biopsied in a low-field MRI system (0.2 T, Concerto, Siemens). The procedures were guided using T 1-weighted Flash sequences (TR/TE = 100/9; 70 degrees). The lesions were repeatedly biopsied using the coaxial technique with a 15-gauge (diameter 2 mm) puncture needle. Complications and biopsy findings were analyzed retrospectively. RESULTS: In all cases the biopsy procedures were successfully performed with MR guidance. In 298 patients diagnosis was able to be confirmed on the basis of the probes. The clinical follow-up showed that in 24 patients the lesions were missed by MR-guided biopsy. From this a sensitivity of 86%, a specificity of 87% and an accuracy of 93% were calculated. In two patients major complications were observed (morbidity rate 0.6 %). CONCLUSION: MR-guided biopsy can be performed safely and precisely in a low-field MR system and are a supplement to US or CT-guided biopsies.

[Transarterial chemoembolization (TACE) in hepatocellular carcinoma: technique, indication and results]. / Transarterielle Chemoembolisation (TACE) des hepatozellulären Karzinoms: Technik, Indikationsstellung und Ergebnisse.

UNLABELLED: To present current data on technique, indications and results of transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC). The principle of TACE is the intra-arterial injection of chemotherapeutic drug combinations like doxorubicin, cisplatin and mitomycin into the hepatic artery, followed by lipiodol injection, Gelfoam for vessel occlusion and degradable microspheres. The side effects and complications after TACE range from fever, upper abdominal pain and vomiting to acute or chronic liver cell failure. The palliative effect in unresectable HCC using TACE allows local tumor control in 15 to 60% of cases and 5-year survival rates ranging from 8-43%. The potentially curative treatment option allows local tumor control from 18-63%. The neoadjuvant treatment option of TACE in combination with other treatment options like percutaneous ethanol injection (PEI) or radiofrequency ablation (RFA) reach local tumor control rates between 80-96%. The bridging effect of TACE before liver transplantation reaches 5-year survival rates from 59-93%. The symptomatic therapy option of TACE is used to counteract pain directly caused by HCC and acute/subacute bleeding in the HCC. The local tumor response reaches up to 88% and the bleeding control is from 83 to 100%. CONCLUSION: TACE is a potentially curative, palliative, neoadjuvant, bridging and symptomatic therapy option for local and diffuse HCC.