Multi-institutional validation of a novel textural analysis tool for preoperative stratification of suspected thyroid tumors on diffusion-weighted MRI.

PURPOSE: Ultrasound-guided fine needle aspirate cytology fails to diagnose many malignant thyroid nodules; consequently, patients may undergo diagnostic lobectomy. This study assessed whether textural analysis (TA) could noninvasively stratify thyroid nodules accurately using diffusion-weighted MRI (DW-MRI). METHODS: This multi-institutional study examined 3T DW-MRI images obtained with spin echo echo planar imaging sequences. The training data set included 26 patients from Cambridge, United Kingdom, and the test data set included 18 thyroid cancer patients from Memorial Sloan Kettering Cancer Center (New York, New York, USA). Apparent diffusion coefficients (ADCs) were compared over regions of interest (ROIs) defined on thyroid nodules. TA, linear discriminant analysis (LDA), and feature reduction were performed using the 21 MaZda-generated texture parameters that best distinguished benign and malignant ROIs. RESULTS: Training data set mean ADC values were significantly different for benign and malignant nodules (P = 0.02) with a sensitivity and specificity of 70% and 63%, respectively, and a receiver operator characteristic (ROC) area under the curve (AUC) of 0.73. The LDA model of the top 21 textural features correctly classified 89/94 DW-MRI ROIs with 92% sensitivity, 96% specificity, and an AUC of 0.97. This algorithm correctly classified 16/18 (89%) patients in the independently obtained test set of thyroid DW-MRI scans. CONCLUSION: TA classifies thyroid nodules with high sensitivity and specificity on multi-institutional DW-MRI data sets. This method requires further validation in a larger prospective study. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance.Grant sponsor: Cancer Research UK Cambridge Institute; Grant number: C14303/A17197; Grant sponsor: Addenbrooke’s Charitable Trust; Grant sponsor: University of Cambridge; Grant sponsor: Cambridge Experimental Cancer Medicine Centre; Grant sponsor: National Institute for Health Research Cambridge Biomedical Research Centre; Grant sponsor: National Cancer Institute/National Institutes of Health; Grant numbers: 1R21CA176660-01A1 and P50 CA172012-01A1.This is the final version. It was first published by Wiley at http://onlinelibrary.wiley.com/doi/10.1002/mrm.25743/abstract;jsessionid=0FB537018C6841C60A3A7244C3702BC2.f03t02

The Image Quality and Radiation Dose of 100-kVp versus 120-kVp ECG-Gated 16-Slice CT Coronary Angiography

Objective: This study was conducted to assess the feasibility of performing 100-kVp electrocardiogram (ECG)-gated coronary CT angiography, as compared to 120-kVp ECG-gated coronary CT angiography. Materials and Methods: We retrospectively evaluated one hundred eighty five gencler- and body mass index-matched 16-slice coronary CT sets of data, which were obtained using either 100 kVp and 620 effective mAs or 120 kVp and 500 effective mAs. The density measurements (image noise, vessel density, signal-to-noise ratio [SNR] and contrast-to-noise ratio [CNR]) and the estimated radiation dose were calculated. As a preference test, two image readers were independently asked to choose one image from each pair of images. The results of both protocols were compared using the paired t-test or the Wilcoxon signed rank test. Results: The 100-kVp images showed significantly more noise and a significantly higher vessel density than did the 120-kVp images. There were no significant differences in the SNR and CNR. The estimated reduction of the radiation dose for the 100-kVp protocol was 24%; 7.8 +/- 0.4 mSV for 1 00-kVp and 10.1 +/- 1.0 mSV for 120-kVp (p < 0.001). The readers preferred the 1 00-kVp images for reading (reader 1, p = 0.01; reader 2, p = 0.06), with their preferences being stronger when the subject`s body mass index was less than 25. Conclusion: Reducing the tube kilovoltage from 120 to 100 kVp allows a significant reduction of the radiation dose without a significant change in the SNR and the CNR.Stolzmann P, 2008, RADIOLOGY, V249, P71, DOI 10.1148/radiol.2483072032Earls JP, 2008, RADIOLOGY, V246, P742, DOI 10.1148/radiol.2463070989Stolzmann P, 2008, EUR RADIOL, V18, P592, DOI 10.1007/s00330-007-0786-8Schoenhagen P, 2008, EUR HEART J, V29, P153, DOI 10.1093/eurheartj/ehm614Heyer CM, 2007, RADIOLOGY, V245, P577, DOI 10.1148/radiol.2452061919Paul JF, 2007, EUR RADIOL, V17, P2028, DOI 10.1007/s00330-007-0584-3McCollough CH, 2007, RADIOLOGY, V243, P775, DOI 10.1148/radiol.2433061165Schueller-Weidekamm C, 2006, RADIOLOGY, V241, P899, DOI 10.1148/radiol.2413040128Hsieh J, 2006, MED PHYS, V33, P4236, DOI 10.1118/1.2361078d`Agostino AG, 2006, EUR RADIOL, V16, P2137, DOI 10.1007/s00330-006-0218-1Hohl C, 2006, EUR RADIOL, V16, P1841, DOI 10.1007/s00330-005-0124-yJohnson TRC, 2006, EUR RADIOL, V16, P1409, DOI 10.1007/s00330-006-0298-yAbada HT, 2006, AM J ROENTGENOL, V186, pS387, DOI 10.2214/AJR.05.0216Hausleiter J, 2006, CIRCULATION, V113, P1305, DOI 10.1161/CIRCULATIONAHA.105.602490NAKAYAMA Y, 2006, AM J ROENTGENOL, V187, pW490Ghersin E, 2006, AM J ROENTGENOL, V186, P177, DOI 10.2214/AJR.04.1232Haberl R, 2005, AM HEART J, V149, P1112, DOI 10.1016/j.ahj.2005.02.048Wintersperger B, 2005, EUR RADIOL, V15, P334, DOI 10.1007/s00330-004-2575-ySigal-Cinqualbre AB, 2004, RADIOLOGY, V231, P169, DOI 10.1148/radiol.2311030191Kalra MK, 2004, RADIOLOGY, V230, P619, DOI 10.1148/radiol.2303021726Jung B, 2003, EUR RADIOL, V13, P2560, DOI 10.1007/s00330-003-2111-5Jakobs TF, 2002, EUR RADIOL, V12, P1081, DOI 10.1007/s00330-001-1278-xHuda W, 2000, RADIOLOGY, V217, P430Kalender WA, 1999, EUR RADIOL, V9, P3231

Meniscal T1rho and T2 measured with 3.0T MRI increases directly after running a marathon

PURPOSE: To prospectively evaluate changes in T1rho and T2 relaxation time in the meniscus using 3.0 T MRI in asymptomatic knees of marathon runners and to compare these findings with those of age-matched healthy subjects. MATERIAL AND METHODS: Thirteen marathon runners underwent 3.0 T MRI including T1rho and T2 mapping sequences before, 48-72 h after, and 3 months after competition. Ten controls were examined at baseline and after 3 months. All images were analyzed by two musculoskeletal radiologists identifying and grading cartilage, meniscal, ligamentous. and other knee abnormalities with WORMS scores. Meniscal segmentation was performed to generate T1rho and T2 maps in six compartments. RESULTS: No differences in morphological knee abnormalities were found before and after the marathon. However, all marathon runners showed a significant increase in T1rho and T2 values after competition in all meniscus compartments (p &lt; 0.0001), which may indicate changes in the biochemical composition of meniscal tissue. While T2 values decreased after 3 months T1rho values remained at a high level, indicating persisting changes in the meniscal matrix composition after a marathon. CONCLUSION: T2 values in menisci have the potential to be used as biomarkers for identifying reversible meniscus matrix changes indicating potential tissue damage. T1rho values need further study, but may be a valuable marker for diagnosing early, degenerative changes in the menisci following exercise

Impingement-Syndrom des oberen Sprunggelenks

Das Impingement-Syndrom des oberen Sprunggelenks (OSG) ist eine klinische Diagnose und entsteht posttraumatisch, überlastungsbedingt durch wiederholte mechanische Belastungen oder durch anatomische Varianten. Es zeichnet sich durch chronisch-rezidivierende Schmerzen und/oder einen eingeschränkten Bewegungsumfang aus. Aufgrund eines pathologischen Engpasses werden Knochen- und/oder Weichteilgewebe zwischen dem Knochen und weiteren Gelenkstrukturen, meist erst bei Bewegung, eingeklemmt. Das Impingement-Syndrom wird in Bezug auf das tibiotalare Gelenk in anterior, anterolateral, anteromedial, posterior und posteromedial eingeteilt. Die radiologische Bildgebung ist von großer Bedeutung, um das morphologische Substrat der Diagnose sichern zu können. Die Projektionsradiographie und die Computertomographie können ossäre Anbauten und freie Gelenkkörper nachweisen. Die Magnetresonanztomographie ist die Modalität der Wahl zum Nachweis pathologischer Veränderungen der Weichteile, des Knochenmarks oder osteochondraler Läsionen. Der dynamische Ultraschall kann die anatomischen Strukturen, die zum Impingement führen, in Bewegung zeigen.(VLID)353207

Intra-operative ultrasound facilitates the localization of the calcific deposit during arthroscopic treatment of calcifying tendinitis

Purpose Calcifying tendinitis is a common condition of the shoulder. In many cases, arthroscopic reduction in the deposit is indicated. The localization of the deposit is sometimes challenging and time-consuming. Pre-operative ultrasound (US)-guided needle placement in the deposit and pre-operative US marking of the deposit at the skin with a ballpoint are described and recommended methods to alleviate the procedure without using ionizing radiation by fluoroscopy. Methods Intra-operative sonography of the shoulder is introduced as a new method to localize the calcific deposit with high accuracy. After standard arthroscopic buresectomy, the surgeon performs an ultrasound examination under sterile conditions to localize the deposits. A ventral longitudinal US section is recommended, and the upper arm is rotated until the deposit is visible. Subsequently, perpendicular to the skin at the position of the transducer, a needle is introduced under arthroscopic and ultrasound visualization to puncture the deposit. Results The presence of snow-white crystals at the tip of the needle proves the exact localization. Consecutively, the curettage can be accomplished. Another intra-operative sonography evaluates possible calcific remnants and the tendon structure. Conclusion This new technique may alleviate arthroscopic calcific deposit curettage by visualizing the deposit without using ionizing radiation. Additionally, soft tissue damage due to decreased number of punctures to detect the deposit may be achieved. Both factors may contribute to reduced operation time