MRI targeted single fraction HDR Brachytherapy for localized Prostate Carcinoma: a feasibility study of focal radiation therapy (ProFocAL).

OBJECTIVES: The aim of the study was to establish the setup and workflow for delivering focal MRI-guided high-dose-rate (HDR) brachytherapy for prostate cancer (PCA) and to assess patient comfort and safety aspects of MRI-guided single-fraction HDR. METHODS: Patients with histologically proven focal low- to intermediate-risk PCA with a single PIRADS 4/5 lesion were treated with percutaneous interstitial HDR brachytherapy in a single fraction with a minimum dose for the gross tumor volume of 20 Gy while sparing the organ at risk (OAR). Using a 3T-MRI, brachytherapy catheters were placed transgluteal in freehand technique. No antibiotic therapy or general analgesics were administered. Patient data, procedure time, patient discomfort, and complications were recorded. Quarterly PSA controls, biannual follow-up imaging, and annual re-biopsy were planned. RESULTS: So far, 9 patients were successfully treated and followed for 6 months. Mean intervention time was 34 min. Using the VAS scale, the pain reported for the intervention ranged from 2 to 3. Short-term follow-up showed no acute genitourinary or gastrointestinal toxicity so far. None of the patients displayed signs of infection. PSA levels in all patients decreased significantly. On follow up no residual PCA was detected treated region so far. PSA levels in all patients decreased significantly. On follow-up, no residual PCA was detected so far. CONCLUSIONS: MR-guided single-fraction focal HDR brachytherapy for localized PCA is feasible as well as safe for the individual patient. Catheters can be placed accurately and maximum therapeutic dose distribution can be restricted to the tumor. Countersigning the minimally invasive character of the procedure, no general anesthesia or antibiosis is necessary. KEY POINTS: • MR-guided focal HDR brachytherapy allows an accurate placement of catheters with maximum therapeutic dose distribution restricted to the tumor. • No major anesthesia or antibiosis is necessary emphasizing the minimal invasive character of the procedure. • Patients with low- and intermediate-risk prostate carcinoma in particular may benefit to halt disease progression whereas treatment-related morbidity is reduced compared with radical therapy.

Transarterial embolisation for the treatment of acute gynecological cancer bleeding.

PURPOSE: Acute bleeding in patients with gynecological cancer may result in serious life-threatening complications. In these situations, immediate diagnostic and appropriate treatment is a challenge for attending physicians. Accordingly, transarterial embolisation (TAE) has been described as an increasing and effective treatment alternative to surgery and radiotherapy. METHODS: In the present retrospective study, 25 patients were included who underwent a TAE in the period from January 2006 to June 2013 due to acute gynecological cancer bleeding. The objective of this study was to assess the efficiency and outcome of TAE. RESULTS: The primary technical success rate was 92.0% (n = 23). 21 patients were analyzed in the 30-day follow-up. The clinical success rate was achieved in 90.5% (n = 19). A clinical failure due to rebleeding was observed in 9.5% (n = 2). No associations were revealed between rebleeding and technical/clinical factors. Within 30 days after the last TAE, the complication and mortality rates were 0.0% and 5.0% (n = 1), respectively. CONCLUSION: TAE was found as an effective and safe treatment in the clinical setting of acute gynecological cancer bleeding. An important component of efficient management is an early and interdisciplinary care. Optimal treatment can be achieved by close cooperation between gynecologists, radiotherapists and interventional radiologists.

Magnetic resonance-guided direct shoulder arthrography for the detection of superior labrum anterior-posterior lesions using an open 1.0-T MRI scanner.

PURPOSE: Direct magnetic resonance arthrography (MRA) offers increased diagnostic accuracy compared to conventional magnetic resonance imaging (MRI) in the detection of superior labrum anterior-posterior (SLAP) lesions. The aim of the present study was to present the technique of magnetic resonance-guided direct shoulder arthrography (MDSA), to evaluate the diagnostic value of this novel MRA procedure to detect SLAP lesions in comparison to the currently practiced MRI, and to correlate the radiological findings to the respective arthroscopic findings. MATERIAL AND METHODS: Fifty-six patients with clinical signs of a SLAP lesion underwent both MRI examination and MDSA prior to arthroscopic surgery. The MRI of both interventions were compared with the arthroscopic findings. Statistical analysis was performed using the McNemar test. RESULTS: Sensitivity, specificity, and accuracy for detecting SLAP lesions were 23%, 88%, and 54% on MRI and 80%, 81%, and 80% on MDSA, respectively. Sensitivity (p < 0.001) and accuracy (p = 0.001) in detection of SLAP lesions were significantly higher by MDSA whereas accuracy showed no significant differences (p = 0.625). CONCLUSIONS: The MDSA can be performed in an open 1.0-T MRI scanner with a high level of technical success and a reasonable methodical effort. The modification of MRA provides the requirements as a practicable routine shoulder magnetic resonance examination including arthrography to detect SLAP lesions. The diagnostic value is significantly better than MRI examinations without included arthrography, which currently predominates the clinical practice to investigate shoulder pathology.

Feasibility study of MR-guided transgluteal targeted in-bore biopsy for suspicious lesions of the prostate at 3 Tesla using a freehand approach.

OBJECTIVE: The aim of our study was (1) to establish an in-bore targeted biopsy of suspicious prostate lesions, avoiding bowel penetration using a transgluteal approach and (2) to assess operator setup, patient comfort and safety aspects in the clinical setting for freehand real-time MR-guidance established for percutaneous procedures in an open MR-scanner. MATERIAL AND METHODS: 30 patients with suspect prostate lesions were biopsied in a cylindrical 3T-MRI system using a transgluteal approach in freehand technique. One to three biopsies were sampled using continuous dynamic imaging. Size, location and visibility of the lesion, intervention time, needle artefact size, interventional complications and histopathological diagnosis were recorded. RESULTS: All biopsies were technically successful. Nineteen patients showed evidence of prostate carcinoma. Cancer detection rate was 50 % in patients with previously negative TRUS-biopsy. The average intervention time was 26 min including a learning curve as the time was 13 min by the end of the study. No antibiotic prophylaxis was performed as none of the patients showed signs of infection. CONCLUSIONS: MR-guided targeted freehand biopsies of prostate lesions using a transgluteal approach are both technically feasible and time efficient in a standard closed-bore 3T-MR scanner as well as safe for the individual patient. KEY POINTS: • Open-bore freehand interventional principles were adapted to closed-bore systems. • Prostate MR-guided freehand biopsies were feasible in a clinical setting. • A transgluteal approach provides a short and simplified work flow. • An inoculation of the prostate with bowel flora is avoided. • The intervention time is comparable to the stereotactic approach.

Freehand direct arthrography of the shoulder using near real-time guidance in an open 1.0-T MRI scanner.

OBJECTIVE: To assess the technical success and duration of magnetic resonance imaging (MRI)-guided freehand direct shoulder arthrography (FDSA) with near real-time imaging implemented in a routine shoulder MRI examination on an open 1.0-T MRI scanner, and to assess the learning curve of residents new to this technique. METHODS: An experienced MRI interventionalist (the expert) performed 125 MRI-guided FDSA procedures, and 75 patients were treated by one of three residents without previous experience in MRI-guided FDSA. Technical success rate and duration of MRI-guided FDSA of the expert and the residents were compared. The residents' learning curves were assessed. The occurrence of extra-articular deposition and leakage of contrast media from the puncture site and the subsequent impairment of image interpretation were retrospectively analyzed. RESULTS: Overall technical success was 97.5 %. The expert needed overall fewer puncture needle readjustments and was faster at puncture needle positioning (p < 0.01). The learning curve of the residents, however, was steep. They leveled with the performance of the expert after ≈ 15 interventions. With a minimal amount of training all steps of MRI-guided FDSA can be performed in ≤10 min. CONCLUSION: Magnetic resonance-guided FDSA in an open 1.0-T MRI scanner can be performed with high technical success in a reasonably short amount of time. Only a short learning curve is necessary to achieve expert level.

Radioablation of liver malignancies with interstitial high-dose-rate brachytherapy : Complications and risk factors.

BACKGROUND: To evaluate complications and identify risk factors for adverse events in patients undergoing high-dose-rate interstitial brachytherapy (iBT). MATERIAL AND METHODS: Data from 192 patients treated in 343 CT- or MRI-guided interventions from 2006-2009 at our institution were analyzed. In 41 %, the largest tumor treated was ≥ 5 cm, 6 % of the patients had tumors ≥ 10 cm. Prior to iBT, 60 % of the patients had chemotherapy, 22 % liver resection, 19 % thermoablation or transarterial chemoembolization (TACE). Safety was the primary endpoint; survival data were obtained as the secondary endpoints. During follow-up, MRI or CT imaging was performed and clinical and laboratory parameters were obtained. RESULTS: The rate of major complications was below 5 %. Five major bleedings (1.5 %) occurred. The frequency of severe bleeding was significantly higher in patients with advanced liver cirrhosis. One patient developed signs of a nonclassic radiation-induced liver disease. In 3 patients, symptomatic gastrointestinal (GI) ulcers were detected. A dose exposure to the GI wall above 14 Gy/ml was a reliable threshold to predict ulcer formation. A combination of C-reactive protein ≥ 165 mg/l and/or leukocyte count ≥ 12.7 Gpt/l on the second day after the intervention predicted infection (sensitivity 90.0 %; specificity 92.8 %.) Two patients (0.6 %) died within 30 days. Median overall survival after the first liver treatment was 20.1 months for all patients and the local recurrence-free surviving proportion was 89 % after 12 months. CONCLUSIONS: Image-guided iBT yields a low rate of major complications and is effective.

Irreversible Electroporation (IRE): Standardization of Terminology and Reporting Criteria for Analysis and Comparison.

BACKGROUND: Irreversible electroporation (IRE) as newer ablation modality has been introduced and its clinical niche is under investigation. At present just one IRE system has been approved for clinical use and is currently commercially available (NanoKnife® system). In 2014, the International Working Group on Image-Guided Tumor Ablation updated the recommendation about standardization of terms and reporting criteria for image-guided tumor ablation. The IRE method is not covered in detail. But the non-thermal IRE method and the NanoKnife System differ fundamentally from established ablations techniques, especially thermal approaches, e.g. radio frequency ablation (RFA). MATERIAL/METHODS: As numerous publications on IRE with varying terminology exist so far - with numbers continuously increasing - standardized terms and reporting criteria of IRE are needed urgently. The use of standardized terminology may then allow for a better inter-study comparison of the methodology applied as well as results achieved. RESULTS: Thus, the main objective of this document is to supplement the updated recommendation for image-guided tumor ablation by outlining a standardized set of terminology for the IRE procedure with the NanoKnife Sytem as well as address essential clinical and technical informations that should be provided when reporting on IRE tumor ablation. CONCLUSIONS: We emphasize that the usage of all above recommended reporting criteria and terms can make IRE ablation reports comparable and provide treatment transparency to assess the current value of IRE and provide further development.

Sensory perceptions of individuals exposed to the static field of a 7T MRI: A controlled blinded study.

PURPOSE: To determine the subjective experience of subjects undergoing 7T magnetic resonance imaging (MRI) compared to a mock scanner with no magnetic field. METHODS AND MATERIALS: In all, 44 healthy subjects were exposed to both the B0 field of a 7T whole-body MRI and a realistic mock scanner with no magnetic field. Subjects were blinded to the actual field strength and no scanning was performed. After exposure, subjects rated their experience of potential sensory perceptions. RESULTS: The most frequently observed side effect was vertigo while entering the gantry, which was reported by 38.6% (n = 17). Other frequent side effects were the appearance of phosphenes (18.2%, n = 8), thermal heat sensation (15.9%), unsteady gait after exposure (13.6%, n = 6), and dizziness (13.6%). All side effects were reported significantly more often after 7T exposure. Nine subjects (20.5%) did not report any sensory perceptions at all, ie, neither in the 7T scanner nor in the mock scanner. CONCLUSION: Light, acute, and transient sensory perceptions can occur in subjects undergoing ultrahighfield MRI, of which vertigo seems to be the most frequently reported. Possible psychological effects might contribute to the emergence of such sensory perceptions, as some subjects also reported them to appear in a realistic mock scanner with no magnetic field.

Feasibility of MRI targeted single fraction HDR brachytherapy for localized prostate carcinoma: ProFocAL-study.

PURPOSE: A potential method for focal therapy in locally advanced prostate cancer is focal brachytherapy (F-BT). The purpose of this research was to evaluate midterm F-BT oncologic, functional, and toxicological results in men who had therapy for prostate cancer. MATERIALS AND METHODS: Between 2016 and 2020, F-BT was used to treat 37 patients with low- to intermediate-risk prostate cancer. The recommended dosage was 20 Gy. Failure was defined as the existence of any prostate cancer that has persisted in-field after treatment. The F-BT oncologic and functional outcomes served as the main and secondary objectives, respectively. RESULTS: A median 20-month follow-up (range 14-48 months). 37 patients received F-BT and enrolled in the study; no patient experienced a biochemical recurrence in the first 24 months, according to Phoenix criteria. In the control biopsies, only 6 patients showed in-field failure. The median initial IPSS was 6.5, at 6 months was 6.0, and at 24 months was 5.0. When the median ICIQ-SF score was 0 at the baseline, it remained 0 at 6-, 12-, and 24 months. Overall survival and biochemical disease-free survival after 3 years were all at 100% and 86.4%, respectively. There was no notable acute gastro-intestinal (GI) or genitourinary (GU) adverse effects. No intraoperative or perioperative complications occurred. CONCLUSIONS: For selected patients with low- or intermediate-risk localized prostate cancer, F-BT is a safe and effective therapy.

MR-guided freehand biopsy of breast lesions in a 1.0-T open MR imager with a near-real-time interactive platform: preliminary experience.

PURPOSE: To identify the most appropriate magnetic resonance (MR) sequence for breast biopsy with regard to lesion visibility and artifact size and to assess feasibility and safety of this approach in a clinical setting. MATERIALS AND METHODS: MR-guided interventions were performed in an open 1.0-T MR imager between November 2009 and January 2011. The prospective clinical study was approved by the institutional review board. Written informed consent was obtained. Four different fast dynamic sequences (balanced steady-state free precession, T1-weighted turbo gradient-echo, T1-weighted turbo spin-echo [SE], and T2-weighted single-shot SE sequences) were evaluated for artifact size of biopsy needle and in vivo for lesion visibility. In vivo breast biopsies were performed with the freehand technique and without immobilization or a positioning device by using an interactive MR mode that allowed continuous imaging in two orthogonal planes for guidance. RESULTS: On the basis of good lesion detection in combination with small artifact size, T1-weighted SE imaging was used for biopsy. A total of 75 biopsies were performed successfully in 69 patients (mean age, 53 years; age range, 35-78 years) (mean lesion size, 7.1 mm; range, 4-15 mm). The interactive MR platform enabled immediate localization and correction of intended needle trajectory. Average time for freehand biopsy was 12 minutes (range, 8-23 minutes). No major complications were recorded. CONCLUSION: MR-guided freehand biopsy of breast lesions with the near-real-time interactive MR platform in an open 1.0-T MR imager is safe and feasible in a clinical setting. The method simplifies work flow and intervention performance.

Estimation of return-to-sports-time for athletes with stress fracture - an approach combining risk level of fracture site with severity based on imaging.

BACKGROUND: The aim was to compare the return-to-sports-time (RTST) following stress fractures on the basis of site and severity of injury. This retrospective study was set up at a single institution. Diagnosis was confirmed by an interdisciplinary adjudication panel and images were rated in a blinded-read setting. METHODS: 52 athletes (female, n = 30; male, n = 22; mean age, 22.8 years) with stress fracture (SFX) who had undergone at least one examination, either MRI or bone scintigraphy, were included. Magnetic resonance images (MRI) and/or bone scintigraphy (BS) of SFX were classified as either low- or high-grade SFX, according to existing grading systems. For MRI, high-grade SFX was defined as visibility of a fracture line or bone marrow edema in T1-, T2-weighted and short tau inversion recovery (STIR) sequences, with low-grade SFX showing no fracture line and bone marrow edema only in STIR and/or T2-weighted sequences. In BS images, a mild and poorly defined focal tracer uptake represented a low-grade lesion, whereas an intense and sharply marginated uptake marked a high-grade SFX. In addition, all injuries were categorized by location as high- or low-risk stress fractures. RTST was obtained from the clinical records. All patients were treated according to a non-weight-bearing treatment plan and comprehensive follow-up data was complete until full recovery. Two-sided Wilcoxon's rank sum test was used for group comparisons. RESULTS: High-risk SFX had a mean RTST of 132 days (d) [IQR 64d - 132d] compared to 119d [IQR 50d - 110d] for low-risk sites (p = 0.19). RTST was significantly longer (p = 0.01) in high-grade lesions [mean, 143d; IQR 66d - 134d] than in low-grade [mean, 95d; IQR 42d - 94d]. Analysis of high-risk SFX showed no difference in RTST (p = 0.45) between high- and low-grade [mean, 131d; IQR 72d - 123d vs. mean, 135d; IQR 63d - 132d]. In contrast, the difference was significant for low-risk SFX (p = 0.005) [low-grade; mean, 61d; IQR 35d - 78d vs. high-grade; mean, 153d; IQR 64d - 164d]. CONCLUSION: For SFX at low-risk sites, the significant difference in RTST between low- and high-grade lesions allows more accurate estimation of RTST by this approach. Both location of the injury and severity determined by imaging should therefore be considered for prediction of RTST.

Assessment of fast dynamic imaging and the use of Gd-EOB-DTPA for MR-guided liver interventions.

PURPOSE: 1) To analyze and compare fast dynamic imaging sequences to biopsy suspect liver lesions. 2) To evaluate the additional use of hepatocyte-specific contrast agent compared to the nonenhanced fast dynamic scans and diagnostic liver imaging. MATERIALS AND METHODS: Image acquisition was performed using a 1T open-configured scanner suitable for interventional purposes. Transversal postcontrast T1-weighted (T1w) fat-saturated 3D high-resolution examination (THRIVE) images were acquired >20 minutes postintravenous application of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid (Gd-EOB-DTPA). A single slice, crossing the level of the lesion, was acquired using intermediate-weighted steady-state free-precession (bTFE), T1w-gradient echo and spin echo (T1FFE/TSE), T2w-spin echo (sshTSE) sequences. T1w imaging was acquired prior and after contrast media application. Diagnostic and fast dynamic images were compared based on a 10-point rating scale. In addition, the liver-to-lesion-contrast ratio was measured. RESULTS: A total of 39 malignant lesions with a mean diameter of 13 mm (5-30 mm) in 39 patients were included. Concerning a test of noninferiority, there was no significant difference between rating score values of fast dynamic imaging employing contrast-enhanced T1FFE-sequences compared to diagnostic THRIVE (P = 0.001). Calculated liver-to-lesion contrast also showed no difference for either imaging sequence (P = 1.0). All other sequences tested showed significant inferiority (P ≤ 0.001). CONCLUSION: T1w Gd-EOB-DTPA contrast-enhanced fast dynamic GRE imaging significantly improves the contrast behavior of malignant liver lesions comparable to diagnostic imaging and is best suited for liver intervention, especially at 1T open magnetic resonance imaging.

MRI-based fat quantification of the liver: Is it time for commercially available products?

PURPOSE: (1) To assess the clinical applicability of commercially available solutions for MR-based quantification of the hepatic fat fraction (HFF) and (2) to compare their results with clinically established in-phase/oppose-phase (IP/OP) imaging as proposed by Dixon. METHODS: Twenty-eight patients underwent MRI examinations using multigradient-echo sequences including multi-peak modeling and T2∗ correction, IP/OP imaging and multi-echo spectroscopy with successive HFF evaluation. Histopathological examination yielded the fraction of adipose hepatocytes (fAH) and the presence of increased liver iron concentration (LIC). We correlated HFF with fAH, and assessed concordance correlations among the MR-based methods with the presence of increased LIC as a control parameter. We investigated the liver segmentation quality and overall workflow of the postprocessing solutions (Philips LiverHealth and Siemens LiverLab). RESULTS: IP/OP imaging yielded a very strong correlation (r=0.88) with fAH when excluding three cases with increased LIC. Multigradient echo imaging and multiecho spectroscopy quantifications yielded similar correlations (r=0.87…0.93) as IP/OP imaging but were insensitive to increased LIC. Visceral fat, kidney tissue and major vessels were included regularly in the segmentation. Spectroscopic fat quantification was sensitive to the inclusion of visceral fat. CONCLUSIONS: IP/OP imaging allows HFF quantification when ruling out hepatic siderosis, whereas dedicated multi-echo imaging sequences and spectroscopy show no bias for increased iron concentration. The segmentation quality and workflow of both postprocessing solutions need to be improved. Nevertheless, all solutions are able to bring MRI-based hepatic fat quantification into the clinical application. We therefore recommend commercial hepatic fat quantification tools for institutions specialised to abdominal imaging.

Diffusion-Weighted Imaging Reflects Tumor Grading and Microvascular Invasion in Hepatocellular Carcinoma.

BACKGROUND: To date, there are inconsistent data about relationships between diffusion-weighted imaging (DWI) and tumor grading/microvascular invasion (MVI) in hepatocellular carcinoma (HCC). Our purpose was to systematize the reported results regarding the role of DWI in prediction of tumor grading/MVI in HCC. METHOD: MEDLINE library, Scopus, and Embase data bases were screened up to December 2019. Overall, 29 studies with 2,715 tumors were included into the analysis. There were 20 studies regarding DWI and tumor grading, 8 studies about DWI and MVI, and 1 study investigated DWI, tumor grading, and MVI in HCC. RESULTS: In 21 studies (1,799 tumors), mean apparent diffusion coefficient (ADC) values (ADCmean) were used for distinguishing HCCs. ADCmean of G1-3 lesions overlapped significantly. In 4 studies (461 lesions), minimum ADC (ADCmin) was used. ADCmin values in G1/2 lesions were over 0.80 × 10-3 mm2/s and in G3 tumors below 0.80 × 10-3 mm2/s. In 4 studies (241 tumors), true diffusion (D) was reported. A significant overlapping of D values between G1, G2, and G3 groups was found. ADCmean and MVI were analyzed in 9 studies (1,059 HCCs). ADCmean values of MIV+/MVI- lesions overlapped significantly. ADCmin was used in 4 studies (672 lesions). ADCmin values of MVI+ tumors were in the area under 1.00 × 10-3 mm2/s. In 3 studies (227 tumors), D was used. Also, D values of MVI+ lesions were predominantly in the area under 1.00 × 10-3 mm2/s. CONCLUSION: ADCmin reflects tumor grading, and ADCmin and D predict MVI in HCC. Therefore, these DWI parameters should be estimated for every HCC lesion for pretreatment tumor stratification. ADCmean cannot predict tumor grading/MVI in HCC.

MR-guided liver tumor ablation employing open high-field 1.0T MRI for image-guided brachytherapy.

OBJECTIVE: To determine the feasibility and safety of image-guided brachytherapy employing a modified open high-field MR system. METHODS: This is a follow-up study of a development project enabling technologies for interventional use of 1.0T open MRI. Modifications included coils and in-bore visualization, fluoroscopic sequences and user interfaces. We recruited 104 patients with 224 liver malignancies to receive MR-guided brachytherapy. Interventions were performed >20 min after Gd-EOB-DTPA. We recorded interventional parameters including the intervention time (from acquisition of the first scout until the final sequence for brachytherapy treatment planning). Two reviewers assessed MR-fluoroscopic images in comparison to plain CT as used in CT intervention, applying a rating scale of 1-10. Statistical analysis included Friedman and Kendall's W tests. RESULTS: We employed freehand puncture with interactive dynamic imaging for navigation. Technical success rate was 218 complete ablations in 224 tumours (97%). The median intervention time was 61 min. We recorded no adverse events related to the use of MRI. No major complications occurred. The rate of minor complications was 4%. Local control at 3 months was 96%. Superiority of MR-fluoroscopic, Gd-EOB-DTPA-enhanced images over plain CT was highly significant (P < 0.001). CONCLUSION: MR-guided brachytherapy employing open high-field MRI is feasible and safe.

Early prediction of anticancer effects with diffusion-weighted MR imaging in patients with colorectal liver metastases following selective internal radiotherapy.

OBJECTIVE: To prospectively evaluate diffusion-weighted imaging (DWI) for early prediction of tumour response in patients with colorectal liver metastases following selective internal radiotherapy (SIRT). METHODS: We evaluated 41 metastases in 21 patients, age 62.9 ± 9.9 years. All patients underwent magnetic resonance imaging (MRI) including breath-hold echoplanar DWI sequences. Imaging was performed before therapy (baseline MRI), 2 days after SIRT (early MRI) as well as 6 weeks later (follow-up MRI). Tumour volume (TV) and intratumoural apparent diffusion coefficient (ADC) were measured independently by two radiologists at all time points. RESULTS: Metastases were categorised as responding lesions (RL; n = 33) or non-responding lesions (NRL; n = 8) according to changes in TV after 6 weeks. We found an inverse correlation of changes in TV and ADC at follow-up MRI with a Pearson's correlation coefficient of r = -0.66 (p < 0.0001). On early MRI, no significant changes in TV were found for either RL or NRL. Conversely, ADC decreased significantly in RL by 10.7 ± 8.4% (p < 0.0001). ADC increased in NRL by 9.6 ± 20.8%, which was not statistically significant (p = 0.40). CONCLUSION: DWI was capable of predicting therapy effects of SIRT in patients with colorectal hepatic metastases as early as 2 days following treatment.

Transarterial embolization of acute iatrogenic hemorrhages: predictive factors for mortality and outcome.

OBJECTIVE: Iatrogenic hemorrhages occur in 0.5-16% of medical procedures. A retrospective study was conducted to analyze technical and clinical outcome of transarterial embolization (TAE) used for acute iatrogenic hemorrhage and to identify factors predicting outcome. METHODS: All patients undergoing TAE for acute iatrogenic bleeding from 2006 to 2013 were retrospectively analyzed. Primary end points were technical and clinical success or failure and 30 day mortality. RESULTS: A total of 153 patients underwent 182 TAEs. Factors associated with clinical failure were lower blood hemoglobin concentration, use of higher number of units of red blood cell concentrate, TAE performed at night or weekend, embolization of more than one vessel, shock state before digital subtraction angiography (DSA), and intensive care before TAE. In multivariate analysis, independent factors for clinical success were hemoglobin concentration, number of units of red blood cell concentrate, and TAE of more than one vessel. Technical failure was associated with female gender, failure to detect signs of bleeding in DSA, TAE of more than one vessel, and shock state before DSA. Bleeding related to anticoagulation medication resulted in a significantly higher mortality rate compared with bleeding due to the remaining causes (30% vs 15%, p < 0.05). CONCLUSION: Despite excellent technical success, the mortality rate was significant. The only factors affecting clinical success were bleeding intensity and extent of injury. Bleeding attributed to anticoagulation is related to high mortality and therefore requires special attention. ADVANCES IN KNOWLEDGE: This study gives insights into morbidity and mortality of iatrogenic bleedings and the technical and clinical success rates of TAE in a large study population.

Respiratory motion artefacts in Gd-EOB-DTPA (Primovist/Eovist) and Gd-DOTA (Dotarem)-enhanced dynamic phase liver MRI after intensified and standard pre-scan patient preparation: A bi-institutional analysis.

OBJECTIVE: The objective of this study is to evaluate if intensified pre-scan patient preparation (IPPP) that comprises custom-made educational material on dynamic phase imaging and supervised pre-imaging breath-hold training in addition to standard informative conversation with verbal explanation of breath-hold commands (standard pre-scan patient preparation-SPPP) might reduce the incidence of gadoxetate disodium (Gd-EOB-DTPA)-related transient severe respiratory motion (TSM) and severity of respiratory motion (RM) during dynamic phase liver MRI. MATERIAL AND METHODS: In this bi-institutional study 100 and 110 patients who received Gd-EOB-DTPA for dynamic phase liver MRI were allocated to either IPPP or SPPP at site A and B. The control group comprised 202 patients who received gadoterate meglumine (Gd-DOTA) of which each 101 patients were allocated to IPPP or SPPP at site B. RM artefacts were scored retrospectively in dynamic phase images (1: none- 5: extensive) by five and two blinded readers at site A and B, respectively, and in the hepatobiliary phase of the Gd-EOB-DTPA-enhanced scans by two blinded readers at either site. RESULTS: The incidence of TSM was 15% at site A and 22.7% at site B (p = 0.157). IPPP did not reduce the incidence of TSM in comparison to SPPP: 16.7% vs. 21.6% (p = 0.366). This finding was consistent at site A: 12% vs. 18% (p = 0.401) and site B: 20.6% vs. 25% (p = 0.590). The TSM incidence in patients with IPPP and SPPP did not differ significantly between both sites (p = 0.227; p = 0.390). IPPP did not significantly mitigate RM in comparison to SPPP in any of the Gd-EOB-DTPA-enhanced dynamic phases and the hepatobiliary phase in patients without TSM (all p≥0.072). In the Gd-DOTA control group on the other hand, IPPP significantly mitigated RM in all dynamic phases in comparison to SPPP (all p≤0.031). CONCLUSIONS: We conclude that Gd-EOB-DTPA-related TSM cannot be mitigated by education and training and that Gd-EOB-DTPA-related breath-hold difficulty does not only affect the subgroup of patients with TSM or exclusively the arterial phase as previously proposed.

Assessment of in vivo 1H magnetic resonance spectroscopy in the liver: a review.

With increased availability of magnetic resonance (MR) systems at ultra-high field strength for clinical studies, other organs besides the brain have received renewed consideration for MR spectroscopy (MRS). Because signal-to-noise ratio and chemical shift increase proportional to the static magnetic field, a concomitant increase in signal intensity and spectral resolution of metabolite resonances can be exploited. Improved resolution of adjacent metabolite peaks would not only provide for more accuracy of metabolite identification but also metabolite quantification. While the superiority of high-field imaging and spectroscopy has already been demonstrated clearly in the brain, this article reviewed issues around 1H MRS of the liver. These include optimization strategies such as coil technology, minimizing of motion artefacts using breath-holding and postprocessing of the spectra. Moreover, we reviewed the pertinent experience hitherto reported in the literature on potential clinical issues where liver MRS may be useful. These included determination and characterization of liver fat content, liver tumours and focal lesions. While these applications have been used experimentally, liver MRS does not yet have a clearly defined role in the clinical management of any disease state. Accordingly, it remains primarily a research modality to date.