Spectral CT in clinical routine imaging of neuroendocrine neoplasms.

AIM: To evaluate the potential of new spectral computed tomography (SCT)-based tools in patients with neuroendocrine neoplasms (NEN). MATERIAL AND METHODS: Eighty-eight consecutive patients with NENs were included prospectively. The patients underwent multiphase CT with spectral and standard mode. The signal-to-noise ratio (SNR)/contrast-to-noise-ratio (CNR)tumour-to-liver, iodine concentrations (ICs, total tumour/hotspot) and attenuation slopes in virtual monochromatic images (VMIs) were used to assess NEN-specific SCT values in primary tumours and metastatic lesions and investigate a possible lesion contrast improvement as well as possible correlations of SCT parameters to primary tumour location and tumour grade. Furthermore, the usability of SCT parameters to differentiate between the primary tumour and metastatic lesions, and to predict tumour response after 6-months follow-up was analyzed. The applied dose of spectral and standard mode was compared intra-individually. RESULTS: SNR/CNRtumour-to-liver significantly increased in low-energy VMIs. NENs showed significant differences in ICs between primary and metastatic lesions for both absolute and normalised values (p<0.001) regardless of whether the total tumour or the hotspot was measured. There was also a significant difference in the attenuation slope (p<0.001). No significant correlations were found between SCT and tumour grade. A tumour response prediction by SCT parameters was not possible. The applied dose was comparable between the scan modes. CONCLUSION: SCT was comparable regarding applied dose, improved tumour contrast, and contributed to differentiation between primary NEN and metastasis.

Switching off for future-Cost estimate and a simple approach to improving the ecological footprint of radiological departments.

PURPOSE: Besides diagnostic imaging devices, in particular computed tomography (CT) and magnetic resonance imaging (MRI), numerous reading workstations contribute to the high energy consumption of radiological departments. It was investigated whether switching off workstations after core working hours can relevantly lower energy consumption considering both ecological and economical aspects. METHODS: Besides calculating different theoretical energy consumption scenarios, we measured power consumption of 3 workstations in our department over a 6-month period under routine working conditions and another 6-month period during which users were asked to switch off workstations after work. Staff costs arising from restarting workstations manually were calculated. RESULTS: Our approach to switching off workstations after core working hours reduced energy consumption by about 5.6 %, corresponding to an extrapolated saving of 3.2 tons in carbon dioxide (CO2) emissions and 2100.70 USD/year in electricity costs for 227 workstations. Theoretical calculations indicate that consistent automatic shutdown after core working hours could result in a potential total reduction of energy consumption of 38.6 %, equaling 22.2 tons of CO2 and 14,388.28 USD/year. However, staff costs resulting from waiting times after manually restarting workstations would amount to 36,280.02 USD/year. CONCLUSIONS: Switching off workstations after core working hours can considerably reduce energy consumption and costs, but varies with user adherence. Staff costs caused by waiting time after manually starting up workstations outweigh energy savings by far. Therefore, an energy-saving plan with automated shutdown/restart besides enabling an energy-saving mode would be the most effective way of saving both energy and costs.

Inter- and Intrareader Agreement of NI-RADS in the Interpretation of Surveillance Contrast-Enhanced CT after Treatment of Oral Cavity and Oropharyngeal Squamous Cell Carcinoma.

BACKGROUND AND PURPOSE: The Neck Imaging Reporting and Data System was introduced to assess the probability of recurrence in surveillance imaging after treatment of head and neck cancer. This study investigated inter- and intrareader agreement in interpreting contrast-enhanced CT after treatment of oral cavity and oropharyngeal squamous cell carcinoma. MATERIALS AND METHODS: This retrospective study analyzed CT datasets of 101 patients. Four radiologists provided the Neck Imaging Reporting and Data System reports for the primary site and neck (cervical lymph nodes). The Kendall's coefficient of concordance (W), Fleiss κ (κF), the Kendall's rank correlation coefficient (τB), and weighted κ statistics (κw) were calculated to assess inter- and intrareader agreement. RESULTS: Overall, interreader agreement was strong or moderate for both the primary site (W = 0.74, κF = 0.48) and the neck (W = 0.80, κF = 0.50), depending on the statistics applied. Interreader agreement was higher in patients with proved recurrence at the primary site (W = 0.96 versus 0.56, κF = 0.65 versus 0.30) or in the neck (W = 0.78 versus 0.56, κF = 0.41 versus 0.29). Intrareader agreement was moderate to strong or almost perfect at the primary site (range τB = 0.67-0.82, κw = 0.85-0.96) and strong or almost perfect in the neck (range τB = 0.76-0.86, κw = 0.89-0.95). CONCLUSIONS: The Neck Imaging Reporting and Data System used for surveillance contrast-enhanced CT after treatment of oral cavity and oropharyngeal squamous cell carcinoma provides acceptable score reproducibility with limitations in patients with posttherapeutic changes but no cancer recurrence.

Prostate Cancer Nodal Staging: Using Deep Learning to Predict 68Ga-PSMA-Positivity from CT Imaging Alone.

Lymphatic spread determines treatment decisions in prostate cancer (PCa) patients. 68Ga-PSMA-PET/CT can be performed, although cost remains high and availability is limited. Therefore, computed tomography (CT) continues to be the most used modality for PCa staging. We assessed if convolutional neural networks (CNNs) can be trained to determine 68Ga-PSMA-PET/CT-lymph node status from CT alone. In 549 patients with 68Ga-PSMA PET/CT imaging, 2616 lymph nodes were segmented. Using PET as a reference standard, three CNNs were trained. Training sets balanced for infiltration status, lymph node location and additionally, masked images, were used for training. CNNs were evaluated using a separate test set and performance was compared to radiologists' assessments and random forest classifiers. Heatmaps maps were used to identify the performance determining image regions. The CNNs performed with an Area-Under-the-Curve of 0.95 (status balanced) and 0.86 (location balanced, masked), compared to an AUC of 0.81 of experienced radiologists. Interestingly, CNNs used anatomical surroundings to increase their performance, "learning" the infiltration probabilities of anatomical locations. In conclusion, CNNs have the potential to build a well performing CT-based biomarker for lymph node metastases in PCa, with different types of class balancing strongly affecting CNN performance.

Improved Visualization of the Necrotic Zone after Microwave Ablation Using Computed Tomography Volume Perfusion in an In Vivo Porcine Model.

After hepatic microwave ablation, the differentiation between fully necrotic and persistent vital tissue through contrast enhanced CT remains a clinical challenge. Therefore, there is a need to evaluate new imaging modalities, such as CT perfusion (CTP) to improve the visualization of coagulation necrosis. MWA and CTP were prospectively performed in five healthy pigs. After the procedure, the pigs were euthanized, and the livers explanted. Orthogonal histological slices of the ablations were stained with a vital stain, digitalized and the necrotic core was segmented. CTP maps were calculated using a dual-input deconvolution algorithm. The segmented necrotic zones were overlaid on the DICOM images to calculate the accuracy of depiction by CECT/CTP compared to the histological reference standard. A receiver operating characteristic analysis was performed to determine the agreement/true positive rate and disagreement/false discovery rate between CECT/CTP and histology. Standard CECT showed a true positive rate of 81% and a false discovery rate of 52% for display of the coagulation necrosis. Using CTP, delineation of the coagulation necrosis could be improved significantly through the display of hepatic blood volume and hepatic arterial blood flow (p < 0.001). The ratios of true positive rate/false discovery rate were 89%/25% and 90%/50% respectively. Other parameter maps showed an inferior performance compared to CECT.

Comparison of different 4D CT-Perfusion algorithms to visualize lesions after microwave ablation in an in vivo porcine model.

Background: Accurate lesion visualization after microwave ablation (MWA) remains a challenge. Computed tomography perfusion (CTP) has been proposed to improve visualization, but it was shown that different perfusion-models delivered different results on the same data set.Purpose: Comparison of different perfusion algorithms and identification of the algorithm enables for the best imaging of lesion after hepatic MWA.Materials and methods: 10 MWA with consecutive CTP were performed in healthy pigs. Parameter-maps were generated using a single-input-dual-compartment-model with Patlak's algorithm (PM), a dual-input-maximum-slope-model (DIMS), a dual-input-one-compartment-model (DIOC), a single-(SIDC) and dual-input-deconvolution-model (DIDC). Parameter-maps for hepatic arterial (AF) and portal venous blood flow (PF), mean transit time, hepatic blood volume (HBV) and capillary permeability were compared regarding the values of the normal liver tissue (NLT), lesion, contrast- and signal-to-noise ratios (SNR, CNR) and inter- and intrarater-reliability using the intraclass correlation coefficient, Bland-Altman plots and linear regression.Results: Perfusion values differed between algorithms with especially large fluctuations for the DIOC. A reliable differentiation of lesion margin appears feasible with parameter-maps of PF and HBV for most algorithms, except for the DIOC due to large fluctuations in PF. All algorithms allowed for a demarcation of the central necrotic zone based on hepatic AF and HBV. The DIDC showed the highest CNR and the best inter- and intrarater reliability.Conclusion: The DIDC appears to be the most feasible model to visualize margins and necrosis zones after microwave ablation, but due to high computational demand, a single input deconvolution algorithm might be preferable in clinical practice.

Spectral CT and its specific values in the staging of patients with non-small cell lung cancer: technical possibilities and clinical impact.

AIM: To investigate how spectral computed tomography (SCT) values impact the staging of non-small cell lung cancer (NSCLC) patients. MATERIALS AND METHODS: One hundred and thirteen patients with confirmed NSCLC were included in a prospective cohort study. All patients underwent single-phase contrast-enhanced SCT (using the fast tube voltage switching technique, 80-140 kV). SCT values (iodine content [IC], spectral slope pitch, and radiodensity increase) of malignant tissue (primary and metastases) and lymph nodes (LNs) were measured. Adrenal masses were evaluated in a virtual non-contrast series (VNS). If pulmonary embolism was present, pulmonary perfusion was analysed as an additional finding. RESULTS: Fifty-two untreated primary NSCLC lesions were evaluable. Lung adenocarcinoma had significantly higher normalised IC (NIC: 19.37) than squamous cell carcinoma (NIC: 12.03; p=0.035). Pulmonary metastases were not significantly different from benign lung nodules. A total of 126 LNs were analysed and histologically proven metastatic LNs (2.08 mg/ml) had significantly lower IC than benign LNs (2.58 mg/ml; p=0.023). Among 34 adrenal masses, VNS identified adenomas with high sensitivity (91%) and specificity (100%). In two patients, a perfusion defect due to pulmonary embolism was detected in the iodine images. CONCLUSION: SCT may contribute to the differentiation of histological NSCLC subtypes and improve the identification of LN metastases. VNS differentiates adrenal adenoma from metastasis. In case of pulmonary embolism, iodine imaging can visualise associated pulmonary perfusion defects.

Multipolar RFA of the liver: Influence of intrahepatic vessels on ablation zones and appropriateness of CECT in detecting ablation dimensions - Results of an in-vivo porcine liver model.

BACKGROUND: Radiofrequency ablation (RFA) is an important treatment option for hepatic tumors and metastases. Post-ablation recurrence rates are reported up to 36.5 percent and seem to depend on tumor size, intrahepatic localization of tumors and adjacent hepatic vessels. Multipolar RFA has the potential to overcome/reduce these limitations. Experimental and standardized data on achievable lesion sizes, influence of hepatic vessels and non-invasive evaluation of complete ablation is still insufficient. OBJECTIVES: The aim of this study was to evaluate the influence of intrahepatic vessels on shape and size of multipolar RF-ablation zones in healthy porcine liver and to evaluate the appropriateness of immediate post-ablation contrast-enhanced computed tomography (CECT) in detecting RF-ablation dimensions. MATERIAL AND METHODS: We conducted multipolar RFAs in each of the livers of 10 healthy, narcotized and laparotomized domestic pigs by inserting three parallel probes with a constant probe distance and a constant energy supply. In 4 ablations we interrupted hepatic blood flow using Pringle's maneuver. Immediate post-ablation CECT scans were acquired. After euthanasia the livers were sliced perpendicularly to the probes at the probes' active centers. CECT scans were reconstructed equivalently in order to compare RF-lesion size and shape to the macroscopic sections. RESULTS: In total, 19 RF-lesions were analyzed. Every RF-lesion that was ablated during physiological liver perfusion showed an irregular and cloverleaf-like shape (n = 15). Interrupting the hepatic blood flow during RFA led to well-defined, round and homogeneous ablation zones which were 3.8 times larger compared to RF-lesions ablated during continuous hepatic perfusion (n = 4). We found an excellent correlation between immediate post-ablation CECT slices and macroscopic sections when comparing RF-lesion diameters and area, although CECT tended to overestimate ablation dimensions. CONCLUSIONS: The interruption of hepatic blood flow using Pringle's maneuver during multipolar RFA with three applicators significantly reduces heat sink effects of hepatic vessels and generates large and coherent ablation zones. This approach should be considered in each case of ablation planning adjacent to larger hepatic vessels or when ablating larger tumor volumes. Immediate post-ablation CECT has limited value in detecting incomplete RFA periprocedurally.

Assessing venous thrombus in renal cell carcinoma: preliminary results for unenhanced 3D-SSFP MRI.

AIM: To test the potential of unenhanced cardiac- and respiratory-motion-corrected three-dimensional steady-state free precession (3D-SSFP) magnetic resonance imaging (MRI) for the assessment of inferior vena cava (IVC) thrombus in patients with clear-cell renal cell carcinoma (cRCC), compared to standard contrast-enhanced (CE)-MRI and CE-computed tomography (CT). MATERIALS AND METHODS: Eighteen patients with cRCC and IVC thrombus, who received CE-MRI and 3D-SSFP at 1.5 T between June 2015 and December 2017, were included. The diagnostic performance of 3D-SSFP in determining the level of thrombus extension, contrast-to-noise ratio (CNR), and image quality were compared with standard MRI/CT and validated against intraoperative and histopathology results. RESULTS: There was 100% agreement between 3D-SSFP, 83.3% agreement between CE-MRI, and 71.4% agreement between CE-CT and surgical findings regarding the level of IVC thrombus. In addition, 3D-SSFP showed a slightly superior estimate of pathological IVC volume. 3D-SSFP reached a significantly higher CNR in the supra- and infrarenal IVC compared to the morphological sequence T2-weighted half-Fourier axial single-shot fast spin-echo (T2-HASTE) and all phases of CE-MRI. More specifically, 3D-SSFP showed a significantly higher CNR in the infrarenal IVC (mean CNR of 10.09±5.74 versus 4.21±2.33 in the delayed phase, p≤0.001) and in the suprarenal IVC (mean CNR of 9.22±4.11 versus 4.84±5.74 in the late arterial phase, p=0.015). CE-CT also was significantly inferior to 3D-SSFP (p≤0.01) and slightly inferior to CE-MRI (p>0.05). The thrombus delineation score for 3D-SSFP (4.38±0.67) was higher compared to CE-MRI (3.76±0.56, p=0.005). CONCLUSION: This preliminary study indicates that 3D-SSFP can achieve an accurate assessment of IVC thrombus in cRCC patients without the need for contrast medium administration, being superior to standard MRI and CT.

Digital breast tomosynthesis versus full-field digital mammography-Which modality provides more accurate prediction of margin status in specimen radiography?

OBJECTIVES: To evaluate the reliability of tumor margin assessment in specimen radiography (SR) using digital breast tomosynthesis (DBT) and full-field digital mammography (FFDM) in comparison to postoperative histopathology margin status as the gold standard. METHODS: After ethics committee approval, 102 consecutive patients who underwent breast conservative surgery for nonpalpable proven breast cancer were prospectively included. All patients underwent ultrasound/mammography-guided wire localization of their lesions. After excision, each specimen was marked for orientation and imaged using FFDM and DBT. Two blinded radiologists (R1, R2) independently analyzed images acquired with both modalities. Readers identified in which direction the lesion was closest to the specimen margin and to measure the margin width. Their findings were compared with the final histopathological analysis. True positive margin status was defined as a margin measuring <1mm for invasive cancer and 5mm for ductal carcinoma in situ (DCIS) at imaging and pathology. RESULTS: For FFDM, correct margin direction was identified in 45 cases (44%) by R1 and in 37 cases (36%) by R2. For DBT, 69 cases (68%) were correctly identified by R1 and 70 cases (69%) by R2. Overall accuracy was 40% for FFDM and 69% for DBT; the difference was statistically significant (p<0.0001). Sensitivity in terms of correct assessment of margin status was significantly better for DBT than FFDM (77% versus 62%). CONCLUSION: SR using DBT is significantly superior to FFDM regarding identification of the closest margin and sensitivity in assessment of margin status.

Evaluation of bone viability in patients after girdlestone arthroplasty: comparison of bone SPECT/CT and MRI.

PURPOSE: To test the diagnostic performance of bone SPECT/CT and MRI for the evaluation of bone viability in patients after girdlestone-arthroplasty with histopathology used as gold standard. MATERIALS AND METHODS: In this cross-sectional study, patients after girdlestone-arthroplasty were imaged with single-photon-emission-computed-tomography/computed-tomography (SPECT/CT) bone-scans using 99mTc-DPD. Additionally, 1.5 T MRI was performed with turbo-inversion-recovery-magnitude (TIRM), contrast-enhanced T1-fat sat (FS) and T1-mapping. All imaging was performed within 24 h prior to revision total-hip-arthroplasty in patients with a girdlestone-arthroplasty. In each patient, four standardized bone-tissue-biopsies (14 patients) were taken intraoperatively at the remaining acetabulum superior/inferior and trochanter major/minor. Histopathological evaluation of bone samples regarding bone viability was used as gold standard. RESULTS: A total of 56 bone-segments were analysed and classified as vital (n = 39) or nonvital (n = 17) by histopathology. Mineral/late-phase SPECT/CT showed a high sensitivity (90%) and specificity (94%) to distinguish viable and nonviable bone tissue. TIRM (sensitivity 87%, specificity 88%) and contrast-enhanced T1-FS (sensitivity 90%, specificity 88%) also achieved a high sensitivity and specificity. T1-mapping achieved the lowest values (sensitivity 82%, specificity 82%). False positive results in SPECT/CT and MRI resulted from small bone fragments close to metal artefacts. CONCLUSIONS: Both bone SPECT/CT and MRI allow a reliable differentiation between viable and nonviable bone tissue in patients after girdlestone arthroplasty. The findings of this study could also be relevant for the evaluation of bone viability in the context of avascular bone necrosis.

MRI of cystic fibrosis lung manifestations: sequence evaluation and clinical outcome analysis.

AIM: To evaluate different magnetic resonance imaging (MRI) sequences for diagnosis of pulmonary manifestations of cystic fibrosis (CF) in comparison to chest computed tomography (CT), including an extended outcome analysis. MATERIALS AND METHODS: Twenty-eight patients with CF (15 male, 13 female, mean age 30.5±9.4 years) underwent CT and MRI of the lung. MRI (1.5 T) included different T2- and T1-weighted sequences: breath-hold HASTE (half Fourier acquisition single shot turbo spin echo) and VIBE (volumetric interpolated breath-hold examination, before and after contrast medium administration) sequences and respiratory-triggered PROPELLER (periodically rotated overlapping parallel lines with enhanced reconstruction) sequences with and without fat signal suppression, and perfusion imaging. CT and MRI images were evaluated by the modified Helbich and the Eichinger scoring systems. The clinical follow-up analysis assessed pulmonary exacerbations within 24 months. RESULTS: The highest concordance to CT was achieved for the PROPELLER sequences without fat signal suppression (concordance correlation coefficient CCC of the overall modified Helbich score 0.93 and of the overall Eichinger score 0.93). The other sequences had the following concordance: PROPELLER with fat signal suppression (CCCs 0.91 and 0.92), HASTE (CCCs 0.87 and 0.89), VIBE (CCCs 0.84 and 0.85) sequences. In the outcome analysis, the combined MRI analysis of all five sequences and a specific MRI protocol (PROPELLER without fast signal suppression, VIBE sequences, perfusion imaging) reached similar correlations to the number of pulmonary exacerbations as the CT examinations. CONCLUSION: An optimum lung MRI protocol in patients with CF consists of PROPELLER sequences without fat signal suppression, VIBE sequences, and lung perfusion analysis to enable high diagnostic efficacy and outcome prediction.

MRI for the detection of calcific features of vertebral haemangioma.

AIM: To evaluate the diagnostic performance of susceptibility-weighted-magnetic-resonance imaging (SW-MRI) for the detection of vertebral haemangiomas (VHs) compared to T1/T2-weighted MRI sequences, radiographs, and computed tomography (CT). MATERIALS AND METHODS: The study was approved by the local ethics review board. An SW-MRI sequence was added to the clinical spine imaging protocol. The image-based diagnosis of 56 VHs in 46 patients was established using T1/T2 MRI in combination with radiography/CT as the reference standard. VHs were assessed based on T1/T2-weighted MRI images alone and in combination with SW-MRI, while radiographs/CT images were excluded from the analysis. RESULTS: Fifty-one of 56 VHs could be identified on T1/T2 MRI images alone, if radiographs/CT images were excluded from analysis. In five cases (9.1%), additional radiographs/CT images were required for the imaging-based diagnosis. If T1/T2 and SW-MRI images were used in combination, all VHs could be diagnosed, without the need for radiography/CT. Size measurements revealed a close correlation between CT and SW-MRI (R2=0.94; p<0.05). CONCLUSIONS: This study demonstrates that SW-MRI enables reliable detection of the typical calcified features of VHs. This is of importance for routine MRI of the spine, as the use of additional CT/radiography can be minimized.

Influence of pelvic volume on surgical outcome after low anterior resection for rectal cancer.

BACKGROUND: Low anterior resection (LAR) for rectal cancer is a potentially challenging operation due to limited space in the pelvis. CT pelvimetry allows to quantify pelvic space, so that its relationship with outcome after LAR may be assessed. Studies investigating this, however, yielded conflicting results. We hypothesized that a small pelvis is associated with a higher rate of incomplete mesorectal excision, anastomotic leakages, and increased rate of urinary dysfunction in patients operated for rectal cancer. METHODS: In a single-center retrospective analysis, we studied 74 patients that underwent LAR for rectal cancer with primary anastomosis. Thin-layered multi-slice CT datasets were used for slice by slice depiction of the inner pelvic surface, and the inner pelvic volume was automatically compounded. The primary outcome was quality of total mesorectal excision (TME; Mercury grading); secondary outcomes were anastomotic leakage and urinary dysfunction with regard to pelvic dimensions. Univariate analyses and multiple logistic regression analyses were performed for the primary and the secondary outcomes. RESULTS: Shorter obstetric conjugate diameters were associated with a higher probability of a worse TME quality (110.8 ± 10.2 vs. 105.0 ± 8.6 mm; OR 0.85; 95% CI 0.73-0.99; p = 0.038). Short interspinous distance showed a trend towards an increased risk for deteriorated TME quality (OR 0.88; 95% CI 0.76-1.0; p = 0.06). Anastomotic leakage was associated with anemia (OR 2.77; 95% CI 1.0-7.7; p = 0.047). Association between pelvic diameters or pelvic volume and anastomotic leakage or urinary dysfunction was not observed. Perioperative blood transfusions were administered more often in patients with postoperative urinary dysfunction (OR 17.67; 95% CI 2.44-127.7; p = 0.004). CONCLUSION: Shorter obstetric conjugate diameter might be a risk factor for incompleteness of total mesorectal excision. Anastomotic leakage seems to be influenced more by clinical factors such as anemia rather than pelvic dimensions. Further studies have to prove the influence of pelvic diameter on local recurrence of rectal cancer after LAR.

Dual-energy CT virtual non-calcium technique for detection of bone marrow edema in patients with vertebral fractures: A prospective feasibility study on a single- source volume CT scanner.

OBJECTIVES: Dual-energy computed tomography (DECT) is a recent development for detecting bone marrow edema (BME) in patients with vertebral compression fractures. The aim of this pilot study was to determine the reliability of single-source DECT in detecting vertebral BME using magnetic resonance imaging (MRI) as standard of reference. MATERIALS AND METHODS: Nine patients with radiographic thoracic or lumbar vertebral compression fractures underwent both, DECT on a 320-row single-source scanner and 1.5T MRI. Virtual non-calcium (VNC) images were reconstructed from the DECT volume datasets. Three blinded readers independently scored images for the presence of BME. Only vertebrae with loss of height in radiography (target vertebrae) were included in the analysis. A vertebra was counted as positive if two readers agreed on the presence of BME. Cohen's kappa was calculated for interrater comparison. Intervertebral ratios of target and the reference vertebra were compared for CT attenuation and MR signal intensity in a reference vertebra using Spearman correlation. Signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) were calculated. RESULTS: Fourteen target vertebrae with a radiographic height loss were identified; eight of them showed BME on MRI, while DECT identified BME in 7 instances. There were no false positive virtual non-calcium images, resulting in a sensitivity of 0.88 (0.75-1.0 among all readers) and specificity of 1.0 (0.81-1.0). Interrater agreement was inferior for DECT (κ=0.63-0.89) compared to MRI (κ=0.9-1.0). Intervertebral ratio in VNC images strongly correlated with short-tau inversion recovery (r=0.87) and inversely with T1 (-0.89). SNR (0.2+/- 0.2 in VNC and 16.7+/- 7.3 in STIR) and CNR (0.2+/- 0.3 and 7.1+/- 6.3) values were inferior in VNC. CONCLUSIONS: Detecting BME with single-source DECT is feasible and allows detection of vertebral compression fractures with reasonably high sensitivity and specificity. However, image quality of VNC reconstructions has to be improved to achieve better interrater agreement. Nonetheless, DECT might accelerate the diagnostic work-flow in patients with vertebral compression fractures in the future and reduce the number of additional MRI examinations.

[Implications of PI-RADS Version 1 and Updated Version 2 on the Scoring of Prostatic Lesions in Multiparametric MRI]. / Prostataläsionen im multiparametrischen MRT: Vergleich der Einflüsse von PI-RADS Version 1 und 2 auf das Scoring.

BACKGROUND: A revised version of the PI-RADS scoring system has been introduced and score-related variability between version 1 and 2 may be suspected. This study aimed to assess the PI-RADS scores derived from version 1 (v1) and the updated version 2 (v2). MATERIAL AND METHODS: 61 patients with biopsy-proven prostate cancer (PCa) and 90 lesions detected on pre-biopsy 3-Tesla multiparametric MRI were included in this retrospective analysis. 2 experienced radiologists scored all lesions in consensus. Lesion scores differing between PI-RADS v1 and v2 were further analyzed. Histology data from radical prostatectomy (RP) were included when available. RESULTS: The PI-RADS v1 and v2 score differed in 52% of patients (32/61) and in 39% of lesions (35/90). On a lesion basis, the reason for the differences were related to sum score in v1 vs. categorical system in v2 in 51% (18/35) of lesions, cutoff between PI-RADS 4 and 5 based on lesion size in v2 as opposed to the sum score in v1 in 31% (11/35) and were inconclusive in 17% (6/35). The RP subgroup indicates enhanced detection of PCas with GS 3+3 and GS 3+4 in v2. CONCLUSION: PI-RADS scores of prostatic lesions frequently differed between v1 and v2, the major reasons for these differences being score-related. In men undergoing RP, PI-RADS v2 improved detection of low risk PCa, but did not increase accuracy for discrimination of GS 3+4 vs. GS≥4+3 compared to v1. Urologists should be aware of the system-related differences when interpreting PI-RADS scores.

Irreversible Electroporation in Interventional Oncology: Where We Stand and Where We Go.

UNLABELLED: Irreversible electroporation (IRE) is the latest in the series of image-guided locoregional tumor ablation therapies. IRE is performed in a nearly non-thermal fashion that circumvents the "heat sink effect" and allows for IRE application in proximity to critical structures such as bile ducts or neurovascular bundles, where other techniques are unsuitable. IRE appears generally feasible and initial reported results for tumor ablation in the liver, pancreas and prostate are promising. Additionally, IRE demonstrates a favorable safety profile. However, site-specific complications include bile leaking or vein thrombosis and may be more severe after pancreatic IRE compared to liver or prostate ablation. There is limited clinical evidence in support of the use of IRE in the kidney. In contrast, pulmonary IRE has so far failed to demonstrate efficacy due to practicability limitations. Hence, this review will provide a state-of-the-art update on available clinical evidence of IRE regarding feasibility, safety and oncologic efficacy. The future role of IRE in the minimally invasive treatment of solid tumors will be discussed. KEY POINTS: • Preclinical findings of IRE have been successfully translated into clinical settings.• Non-thermal ablation is able to prevent the "heat sink effect" and collateral damage.• IRE should primarily be applied to tumors adjacent to sensitive structures (e. g. bile ducts).IRE efficacy appears promising in the liver, pancreas and prostate with tolerable morbidity.• In contrast, there are no evidential benefits of IRE in the lung parenchyma. Citation Format: • Savic LJ, Chapiro J, Hamm B et al. Irreversible Electroporation in Interventional Oncology: Where We Stand and Where We Go. Fortschr Röntgenstr 2016; 188: 735 - 745.

Radiation dose reduction in CT with adaptive statistical iterative reconstruction (ASIR) for patients with bronchial carcinoma and intrapulmonary metastases.

AIM: To compare the radiation dose and image quality of 64-row chest computed tomography (CT) in patients with bronchial carcinoma or intrapulmonary metastases using full-dose CT reconstructed with filtered back projection (FBP) at baseline and reduced dose with 40% adaptive statistical iterative reconstruction (ASIR) at follow-up. MATERIALS AND METHODS: The chest CT images of patients who underwent FBP and ASIR studies were reviewed. Dose-length products (DLP), effective dose, and size-specific dose estimates (SSDEs) were obtained. Image quality was analysed quantitatively by signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) measurement. In addition, image quality was assessed by two blinded radiologists evaluating images for noise, contrast, artefacts, visibility of small structures, and diagnostic acceptability using a five-point scale. RESULTS: The ASIR studies showed 36% reduction in effective dose compared with the FBP studies. The qualitative and quantitative image quality was good to excellent in both protocols, without significant differences. There were also no significant differences for SNR except for the SNR of lung surrounding the tumour (FBP: 35±17, ASIR: 39±22). DISCUSSION: A protocol with 40% ASIR can provide approximately 36% dose reduction in chest CT of patients with bronchial carcinoma or intrapulmonary metastases while maintaining excellent image quality.

Brain parenchymal damage in neuromyelitis optica spectrum disorder - A multimodal MRI study.

OBJECTIVE: To investigate different brain regions for grey (GM) and white matter (WM) damage in a well-defined cohort of neuromyelitis optica spectrum disorder (NMOSD) patients and compare advanced MRI techniques (VBM, Subcortical and cortical analyses (Freesurfer), and DTI) for their ability to detect damage in NMOSD. METHODS: We analyzed 21 NMOSD patients and 21 age and gender matched control subjects. VBM (GW/WM) and DTI whole brain (TBSS) analyses were performed at different statistical thresholds to reflect different statistical approaches in previous studies. In an automated atlas-based approach, Freesurfer and DTI results were compared between NMOSD and controls. RESULTS: DTI TBSS and DTI atlas based analysis demonstrated microstructural impairment only within the optic radiation or in regions associated with the optic radiation (posterior thalamic radiation p < 0.001, 6.9 % reduction of fractional anisotropy). VBM demonstrated widespread brain GM and WM reduction, but only at exploratory statistical thresholds, with no differences remaining after correction for multiple comparisons. Freesurfer analysis demonstrated no group differences. CONCLUSION: NMOSD specific parenchymal brain damage is predominantly located in the optic radiation, likely due to a secondary degeneration caused by ON. In comparison, DTI appears to be the most reliable and sensitive technique for brain damage detection in NMOSD. KEY POINTS: • The hypothesis of a widespread brain damage in NMOSD is challenged. • The optic radiation (OR) is the most severely affected region. • OR-affection is likely due to secondary degeneration following optic neuritis. • DTI is currently the most sensitive technique for NMOSD-related brain-damage detection. • DTI is currently the most reliable technique for NMOSD-related brain-damage detection.

Use of Paclitaxel-Coated Balloon Catheter Dilation to Reduce In-Stent Restenosis in Transjugular Intrahepatic Portosystemic Shunt (TIPS).

PURPOSE: Paclitaxel-coated balloons (PCB) inhibit neointimal proliferation in arteries. The purpose of this retrospective analysis was to investigate the effect of PCB in in-stent restenosis after transjugular intrahepatic portosystemic shunt (TIPS) in patients with cirrhotic liver disease. MATERIALS AND METHODS: Six patients (mean age: 65 ±â€Š10 years) with recurrent in-stent restenoses in TIPS (5 bare stents, 1 covered stent) underwent a single percutaneous transluminal angioplasty (PTA) with PCB (3 µg paclitaxel/mm(2)). Post-interventional outcome and patency were compared with those of prior plain optimal balloon angioplasty (POBA) in the same patients. During a two-year follow-up period, all patients underwent angiographic examinations at 6-month intervals. In-stent minimal lumen diameter (MLD) and late lumen loss (LLL) were assessed. Paclitaxel residues on balloon and sheath surfaces as well as venous plasma concentrations (0 - 24 hours) were analyzed. RESULTS: PCB decreased the need for clinically driven repeat PTA (POBA: 53 % of angiographic examinations; paclitaxel PTA: 19 %; P = 0.014). LLL/diameter stenosis was higher after POBA (2.4 ±â€Š1.5 mm/28 ±â€Š18 %) than after PCB (0.5 ±â€Š0.8 mm/7 ±â€Š11 %, P = 0.029). Residual paclitaxel on balloons was 28 ±â€Š9 % of dose and 0.2 ±â€Š0.1 % on sheath surfaces. Paclitaxel plasma concentrations were below detectable levels throughout the first 24 hours after the interventions in all patients. The procedure was well tolerated and no clinical side effects attributable to paclitaxel were observed. CONCLUSION: In patients with recurrent in-stent stenoses, a single PTA with PCB resulted in a prolonged secondary patency due to pseudointimahyperplasia without a systemic effect of paclitaxel. KEY POINTS: •Intimahyperplasia is a common reason for long-time TIPS dysfunction. •First-in-man local paclitaxel application in TIPS patients with recurrent in-stent stenoses. •PTA with PCB resulted in a prolonged secondary patency compared to POBA. •No systemic effects of Paclitaxel were detected.