Vascular 3D Printing with a Novel Biological Tissue Mimicking Resin for Patient-Specific Procedure Simulations in Interventional Radiology: a Feasibility Study.

Three-dimensional (3D) printing of vascular structures is of special interest for procedure simulations in Interventional Radiology, but remains due to the complexity of the vascular system and the lack of biological tissue mimicking 3D printing materials a technical challenge. In this study, the technical feasibility, accuracy, and usability of a recently introduced silicone-like resin were evaluated for endovascular procedure simulations and technically compared to a commonly used standard clear resin. Fifty-four vascular models based on twenty-seven consecutive embolization cases were fabricated from preinterventional CT scans and each model was checked for printing success and accuracy by CT-scanning and digital comparison to its original CT data. Median deltas (Δ) of luminal diameters were 0.35 mm for clear and 0.32 mm for flexible resin (216 measurements in total) with no significant differences (p > 0.05). Printing success was 85.2% for standard clear and 81.5% for the novel flexible resin. In conclusion, vascular 3D printing with silicone-like flexible resin was technically feasible and highly accurate. This is the first and largest consecutive case series of 3D-printed embolizations with a novel biological tissue mimicking material and is a promising next step in patient-specific procedure simulations in Interventional Radiology.

Surgical and radiological behavior of MRI-depictable mesh implants after TAPP repair: the IRONMAN study.

PURPOSE: Knowledge of postoperative behavior of mesh implants used for hernia repair is generally limited to cases of recurrence, local complications or return to the previous operative field in other pathological conditions. Previous studies with MRI-visible mesh implants in different parts of the abdominal wall have led to variable findings with regard to mesh properties and mostly described a reduction in size over time with subsequently limited mesh overlap over hernia defects which could contribute to recurrence. We aimed to evaluate implant properties in a mechanically stable anatomical region after TAPP repair of primary unilateral inguinal hernias in men with clinical and MRI examinations 4 weeks and 1 year after surgery. METHODS: From 11/2015 to 01/2019, 23 men with primary, unilateral, inguinal hernias underwent TAPP repair with iron particle-loaded, MRI-visible mesh implants in a prospective cohort study. In 16 patients the operative outcome could be evaluated 4 weeks and 12 months after surgery by clinical examination and MRI evaluation with regard to postoperative course, possible adverse outcomes and radiological findings related to implant behavior-namely MRI-identifiability, mesh dislocation or reduction in surface area. RESULTS: All included patients had an uneventful postoperative clinical course. MRI after 4 weeks revealed one postoperative seroma, which resolved spontaneously. No recurrence was detected. Mesh implants could be accurately delineated in DIXON-IN studies and showed neither clinically nor statistically significant changes in size or position. CONCLUSION: 4 weeks and 1 year after a standardized TAPP procedure the mesh implant used in this study showed no tendency towards dislocation or reduction in size in this anatomical position. Its MRI visibility allows accurate delineation during the postoperative course by experienced radiologists in appropriate MRI protocols. Larger patient series are desirable to further support these findings. Shrinkage of implants in the groin as a reason for early recurrence may be overestimated.

Comparison of tissue distribution, phrenic nerve involvement, and epidural spread in standard- vs low-volume ultrasound-guided interscalene plexus block using contrast magnetic resonance imaging: a randomized, controlled trial.

BACKGROUND: Ultrasound guidance allows for the use of much lower volumes of local anaesthetics for nerve blocks, which may be associated with less aberrant spread and fewer complications. This randomized, controlled study used contrast magnetic resonance imaging to view the differential-volume local anaesthetic distribution, and compared analgesic efficacy and respiratory impairment. METHODS: Thirty patients undergoing shoulder surgery were randomized to receive ultrasound-guided interscalene block by a single, blinded operator with injection of ropivacaine 0.75% (either 20 or 5 ml) plus the contrast dye gadopentetate dimeglumine, followed by magnetic resonance imaging. The primary outcome was epidural spread. Secondary outcomes were central non-epidural spread, contralateral epidural spread, spread to the phrenic nerve, spirometry, ultrasound investigation of the diaphragm, block duration, pain scores during the first 24 h, time to first analgesic consumption, and total analgesic consumption. RESULTS: All blocks provided fast onset and adequate intra- and postoperative analgesia, with no significant differences in pain scores at any time point. Epidural spread occurred in two subjects of each group (13.3%); however, spread to the intervertebral foramen and phrenic nerve and extensive i.m. local anaesthetic deposition were significantly more frequent in the 20 ml group. Diaphragmatic paralysis occurred twice as frequently (n=8 vs 4), and changes from baseline peak respiratory flow rate were larger [Δ=-2.66 (1.99 sd) vs -1.69 (2.0 sd) l min(-1)] in the 20 ml group. CONCLUSIONS: This study demonstrates that interscalene block is associated with epidural spread irrespective of injection volume; however, less central (foraminal) and aberrant spread after low-volume injection may be associated with a more favourable risk profile. CLINICAL TRIAL REGISTRATION: This study was registered with the European Medicines Agency (Eudra-CT number 2013-004219-36) and with the US National Institutes' of Health registry and results base, clinicaltrials.gov (identifier NCT02175069).

[Gynecological tumors of the true pelvis: Radiological diagnosis for pelvic tumors made simple]. / Gynäkologische Tumoren im kleinen Becken: Radiologische Diagnostik bei Beckentumoren leicht gemacht.

Tumors of the reproductive organs are among the most common female tumors. Computed tomography (CT) and magnetic resonance imaging (MRI) are used for establishing the differential diagnosis, for staging and increasingly for treatment stratification. Sonography is the first line imaging modality for assessing benign and malignant tumors of the uterus as well as ovarian and adnexal lesions. In sonographically indeterminate masses MRI is used for clarification as it allows not only a prediction of the dignity but also in most cases a specific diagnosis. The MRI examination is also superior to CT in the assessment of tumors resembling benign pelvic lesions. Whereas MRI has become established as the modality of choice for local staging and treatment planning in cancers of the uterine cervix and endometrial cancer, CT is used for staging of ovarian cancer due to the propensity for peritoneal spread outside the pelvis at the time of initial diagnosis.

Added value of semi-quantitative breast-specific gamma imaging in the work-up of suspicious breast lesions compared to mammography, ultrasound and 3-T MRI.

OBJECTIVE: To prospectively analyse the diagnostic value of semi-quantitative breast-specific gamma imaging (BSGI) in the work-up of suspicious breast lesions compared with that of mammography (MG), breast ultrasound and MRI of the breast. METHODS: Within a 15-month period, 67 patients with 92 breast lesions rated as Category IV or V according to the breast imaging reporting and data system detected with MG and/or ultrasound were included into the study. After the injection of 740-1110 MBq of Technetium-99m ((99m)Tc) SestaMIBI intravenously, scintigrams were obtained in two projections comparable to MG. The BSGI was analysed visually and semi-quantitatively by calculating a relative uptake factor (X). With the exception of two patients with cardiac pacemakers, all patients underwent 3-T breast MRI. Biopsy results were obtained as the reference standard in all patients. Sensitivity, specificity, positive- and negative-predictive values, accuracy and area under the curve were calculated for each modality. RESULTS: Among the 92 lesions, 67 (72.8%) were malignant. 60 of the 67 cancers of any size were detected by BSGI with an overall sensitivity of 90%, only exceeded by ultrasound with a sensitivity of 99%. The sensitivity of BSGI for lesions <1 cm declined significantly to 60%. Overall specificity of ultrasound was only 20%. Specificity, accuracy and positive-predictive value were the highest for BSGI (56%, 80% and 85%, respectively). X was significantly higher for malignant lesions (mean, 4.27) and differed significantly between ductal types (mean, 4.53) and the other histopathological entities (mean, 3.12). CONCLUSION: Semi-quantitative BSGI with calculation of the relative uptake factor (X) can help to characterize breast lesions. BSGI negativity may obviate the need for biopsy of breast lesions >1 cm with low or intermediate prevalence for malignancy. ADVANCES IN KNOWLEDGE: Compared with morphological imaging modalities, specificity, positive-predictive value for malignancy and accuracy were the highest for BSGI in our study. BSGI negativity may support the decision not to biopsy in selected lesions with a low or low-to-moderate pre-test probability for malignancy.

[Imaging of transmesocolic internal hernias following retrocolic Roux-Y reconstruction: tips and tricks for radiologists]. / Bildgebung transmesokolischer innerer Hernien nach retrokolischer Roux-Y-Rekonstruktion: Tipps und Tricks für Radiologen.

Among all entities causing intestinal obstruction, internal hernias are rare. However, after retrocolic laparoscopic Roux-Y reconstruction, transmesocolic internal hernias may occur. The loss of mesenteric fat favors the formation of transmesocolic internal hernias, which are the most common type of acquired internal hernias. CT findings of segmental intestinal obstruction are similar in all underlying diseases including peritoneal adhesions, which are the most important differential diagnosis to postoperative internal hernias. Since internal hernias typically alter spatial relationships within the peritoneal cavity, precise analysis of intraperitoneal topography is the most important clue to differentiate internal hernias from peritoneal adhesions. Based on readily identifiable anatomic reference points and structures, so-called landmarks, specific features of internal hernias in CT imaging are outlined. Particular attention is paid to mesenteries, because they define compartments within the peritoneal cavity. Focusing on transmesocolic internal hernias, the anatomy of the mesocolon transversum is described in detail. Finally, we present a checklist facilitating the diagnosis of internal hernias in everyday practice.

[Radiological diagnostics of ovarian cancer]. / Radiologische Diagnostik des Ovarialkarzinoms.

Ovarian cancer is diagnosed in stages FIGO III/IV in up to 75% of cases. Despite medical advances the 5-year survival rate has only been moderately increased to 44% during recent years. The initial evaluation is performed using transvaginal ultrasound (US) (sensitivity 90-96%, specificity 98-99% for detection of ovarian lesions). Probably benign findings will be followed-up sonographically or will be laparoscopically excised. Magnetic resonance imaging (MRI) allows a definitive diagnosis in more than 90% of sonographically indeterminate lesions. Malignant lesions require computer tomography (CT) staging and treatment in gynecology centers in a multidisciplinary setting. Peritoneal implants larger than 1 cm are detected equally by CT and MRI. Detection of ascites which is associated with peritoneal carcinomatosis in up to 80% of cases is equally feasible by US, CT and MRI.