| 1. |
|
|
| 2. |
|
|
| 3. |
- Shimwell, T. W., et al.
(författare)
-
The LOFAR Two-metre Sky Survey: V. Second data release
- 2022
-
Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 659
-
Tidskriftsartikel (refereegranskat)abstract
- In this data release from the ongoing LOw-Frequency ARray (LOFAR) Two-metre Sky Survey we present 120a 168 MHz images covering 27% of the northern sky. Our coverage is split into two regions centred at approximately 12h45m +44 30a and 1h00m +28 00a and spanning 4178 and 1457 square degrees respectively. The images were derived from 3451 h (7.6 PB) of LOFAR High Band Antenna data which were corrected for the direction-independent instrumental properties as well as direction-dependent ionospheric distortions during extensive, but fully automated, data processing. A catalogue of 4 396 228 radio sources is derived from our total intensity (Stokes I) maps, where the majority of these have never been detected at radio wavelengths before. At 6a resolution, our full bandwidth Stokes I continuum maps with a central frequency of 144 MHz have: a median rms sensitivity of 83 μJy beama 1; a flux density scale accuracy of approximately 10%; an astrometric accuracy of 0.2a; and we estimate the point-source completeness to be 90% at a peak brightness of 0.8 mJy beama 1. By creating three 16 MHz bandwidth images across the band we are able to measure the in-band spectral index of many sources, albeit with an error on the derived spectral index of > a ±a 0.2 which is a consequence of our flux-density scale accuracy and small fractional bandwidth. Our circular polarisation (Stokes V) 20a resolution 120a168 MHz continuum images have a median rms sensitivity of 95 μJy beama 1, and we estimate a Stokes I to Stokes V leakage of 0.056%. Our linear polarisation (Stokes Q and Stokes U) image cubes consist of 480a A a 97.6 kHz wide planes and have a median rms sensitivity per plane of 10.8 mJy beama 1 at 4a and 2.2 mJy beama 1 at 20a; we estimate the Stokes I to Stokes Q/U leakage to be approximately 0.2%. Here we characterise and publicly release our Stokes I, Q, U and V images in addition to the calibrated uv-data to facilitate the thorough scientific exploitation of this unique dataset.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Di Legge, A., et al.
(författare)
-
Lesion size affects diagnostic performance of IOTA logistic regression models, IOTA simple rules and risk of malignancy index in discriminating between benign and malignant adnexal masses
- 2012
-
Ingår i: Ultrasound in Obstetrics & Gynecology. - : Wiley. - 1469-0705 .- 0960-7692. ; 40:3, s. 345-354
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives To estimate the ability to discriminate between benign and malignant adnexal masses of different size using: subjective assessment, two International Ovarian Tumor Analysis (IOTA) logistic regression models (LR1 and LR2), the IOTA simple rules and the risk of malignancy index (RMI). Methods We used a multicenter IOTA database of 2445 patients with at least one adnexal mass, i.e. the database previously used to prospectively validate the diagnostic performance of LR1 and LR2. The masses were categorized into three subgroups according to their largest diameter: small tumors (diameter < 4 cm; n = 396), medium-sized tumors (diameter, 49.9 cm; n = 1457) and large tumors (diameter = 10 cm, n = 592). Subjective assessment, LR1 and LR2, IOTA simple rules and the RMI were applied to each of the three groups. Sensitivity, specificity, positive and negative likelihood ratio (LR+, LR-), diagnostic odds ratio (DOR) and area under the receiveroperating characteristics curve (AUC) were used to describe diagnostic performance. A moving window technique was applied to estimate the effect of tumor size as a continuous variable on the AUC. The reference standard was the histological diagnosis of the surgically removed adnexal mass. Results The frequency of invasive malignancy was 10% in small tumors, 19% in medium-sized tumors and 40% in large tumors; 11% of the large tumors were borderline tumors vs 3% and 4%, respectively, of the small and medium-sized tumors. The type of benign histology also differed among the three subgroups. For all methods, sensitivity with regard to malignancy was lowest in small tumors (5684% vs 6793% in medium-sized tumors and 7495% in large tumors) while specificity was lowest in large tumors (6087%vs 8395% in medium-sized tumors and 8396% in small tumors ). The DOR and the AUC value were highest in medium-sized tumors and the AUC was largest in tumors with a largest diameter of 711 cm. Conclusion Tumor size affects the performance of subjective assessment, LR1 and LR2, the IOTA simple rules and the RMI in discriminating correctly between benign and malignant adnexal masses. The likely explanation, at least in part, is the difference in histology among tumors of different size. Copyright (C) 2012 ISUOG. Published by John Wiley & Sons, Ltd.
|
|
| 7. |
- Dierickx, I., et al.
(författare)
-
Imaging in gynecological disease (7): clinical and ultrasound features of Brenner tumors of the ovary
- 2012
-
Ingår i: Ultrasound in Obstetrics & Gynecology. - : Wiley. - 1469-0705 .- 0960-7692. ; 40:6, s. 706-713
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives To describe clinical and ultrasound features of Brenner tumors of the ovary. Methods In this retrospective study, the databases of the International Ovarian Tumor Analysis (IOTA) studies and one tertiary center were searched to identify patients who had undergone an ultrasound scan before surgery for an adnexal mass that proved to be a Brenner tumor. Twenty-eight patients with 29 Brenner tumors were included, most of which had been collected within the framework of the IOTA studies. An experienced ultrasound examiner reviewed available ultrasound images (available for 14 tumors), searching for a pattern specific to Brenner tumors. Results Most patients were postmenopausal and asymptomatic. Twenty-four (83%) tumors were benign, two (7%) were borderline and three (10%) were malignant. Most benign tumors (17/24, 71%) contained solid components and manifested no or minimal blood flow on Doppler examination (19/24, 79%). Information about calcifications was available for 15 benign tumors, and in 13 (87%) calcifications were present. The five borderline and invasively malignant tumors contained solid components less often than did the benign ones (3/5, 60%) and were more richly vascularized on Doppler examination. Information about calcifications was available for four borderline or invasively malignant tumors, and in three (75%) calcifications were present. Conclusion We failed to demonstrate ultrasound features specific to Brenner tumors. A prospective study is needed to determine if ultrasound features of calcifications can discriminate between Brenner tumors and other types of ovarian tumor. Copyright (c) 2012 ISUOG. Published by John Wiley & Sons, Ltd.
|
|
| 8. |
- Jordans, I. P.M., et al.
(författare)
-
Definition and sonographic reporting system for Cesarean scar pregnancy in early gestation : modified Delphi method
- 2022
-
Ingår i: Ultrasound in Obstetrics and Gynecology. - : Wiley. - 0960-7692 .- 1469-0705. ; 59:4, s. 437-449
-
Tidskriftsartikel (refereegranskat)abstract
- Objective: To develop a standardized sonographic evaluation and reporting system for Cesarean scar pregnancy (CSP) in the first trimester, for use by both general gynecology and expert clinics. Methods: A modified Delphi procedure was carried out, in which 28 international experts in obstetric and gynecological ultrasonography were invited to participate. Extensive experience in the use of ultrasound to evaluate Cesarean section (CS) scars in early pregnancy and/or publications concerning CSP or niche evaluation was required to participate. Relevant items for the detection and evaluation of CSP were determined based on the results of a literature search. Consensus was predefined as a level of agreement of at least 70% for each item, and a minimum of three Delphi rounds were planned (two online questionnaires and one group meeting). Results: Sixteen experts participated in the Delphi study and four Delphi rounds were performed. In total, 58 items were determined to be relevant. We differentiated between basic measurements to be performed in general practice and advanced measurements for expert centers or for research purposes. The panel also formulated advice on indications for referral to an expert clinic. Consensus was reached for all 58 items on the definition, terminology, relevant items for evaluation and reporting of CSP. It was recommended that the first CS scar evaluation to determine the location of the pregnancy should be performed at 6–7 weeks' gestation using transvaginal ultrasound. The use of magnetic resonance imaging was not considered to add value in the diagnosis of CSP. A CSP was defined as a pregnancy with implantation in, or in close contact with, the niche. The experts agreed that a CSP can occur only when a niche is present and not in relation to a healed CS scar. Relevant sonographic items to record included gestational sac (GS) size, vascularity, location in relation to the uterine vessels, thickness of the residual myometrium and location of the pregnancy in relation to the uterine cavity and serosa. According to its location, a CSP can be classified as: (1) CSP in which the largest part of the GS protrudes towards the uterine cavity; (2) CSP in which the largest part of the GS is embedded in the myometrium but does not cross the serosal contour; and (3) CSP in which the GS is partially located beyond the outer contour of the cervix or uterus. The type of CSP may change with advancing gestation. Future studies are needed to validate this reporting system and the value of the different CSP types. Conclusion: Consensus was achieved among experts regarding the sonographic evaluation and reporting of CSP in the first trimester.
|
|
| 9. |
- Ludovisi, M., et al.
(författare)
-
Imaging in gynecological disease (9): clinical and ultrasound characteristics of tubal cancer
- 2014
-
Ingår i: Ultrasound in Obstetrics & Gynecology. - : Wiley. - 1469-0705 .- 0960-7692. ; 43:3, s. 328-335
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives To describe clinical history and ultrasound findings in patients with tubal carcinoma. Methods Patients with a histological diagnosis of tubal cancer who had undergone preoperative ultrasound examination were identified from the databases of 13 ultrasound centers. The tumors were described by the principal investigator at each contributing center on the basis of ultrasound images, ultrasound reports and research protocols (when applicable) using the terms and definitions of the International Ovarian Tumor Analysis (IOTA) group. In addition, three authors reviewed together all available digital ultrasound images and described them using subjective evaluation of gray-scale and color Doppler ultrasound findings. Results We identified 79 women with a histological diagnosis of primary tubal cancer, 70 of whom (89%) had serous carcinomas and 46 (58%) of whom presented at FIGO stage III. Forty-nine (62%) women were asymptomatic (incidental finding), whilst the remaining 30 complained of abdominal bloating or pain. Fifty-three (67%) tumors were described as solid at ultrasound examination, 14 (18%) as multilocular solid, 10 (13%) as unilocular solid and two (3%) as unilocular. No tumor was described as a multilocular mass. Most tumors (70/79, 89%) were moderately or very well vascularized on color or power Doppler ultrasound. Normal ovarian tissue was identified adjacent to the tumor in 51% (39/77) of cases. Three types of ultrasound appearance were identified as being typical of tubal carcinoma using pattern recognition: a sausage-shaped cystic structure with solid tissue protruding into it like a papillary projection (11/62, 18%); a sausage-shaped cystic structure with a large solid component filling part of the cyst cavity (13/62, 21%); an ovoid or oblong completely solid mass (36/62, 58%). Conclusions A well vascularized ovoid or sausage-shaped structure, either completely solid or with large solid component(s) in the pelvis, should raise the suspicion of tubal cancer, especially if normal ovarian tissue is seen adjacent to it. Copyright (C) 2013 ISUOG. Published by John Wiley & Sons Ltd.
|
|
| 10. |
- Sokalska, A., et al.
(författare)
-
Diagnostic accuracy of transvaginal ultrasound examination for assigning a specific diagnosis to adnexal masses
- 2009
-
Ingår i: Ultrasound in Obstetrics & Gynecology. - : Wiley. - 1469-0705 .- 0960-7692. ; 34:4, s. 462-470
-
Tidskriftsartikel (refereegranskat)abstract
- Objectives To determine the sensitivity and specificity of subjective evaluation of gray-scale and Doppler ultrasound findings (here called pattern recognition) when used by experienced ultrasound examiners with regard to making a specific diagnosis of adnexal masses. Methods Within the framework of a European multi-center study, the International Ovarian Tumor Analysis study, comprising nine ultrasound centers, women with at least one adnexal mass were examined with gray-scale and color Doppler ultrasonography by experienced ultrasound examiners. A standardized examination technique, and standardized terms and definitions were used. Using pattern recognition the examiners classified each mass as benign or malignant and suggested a specific diagnosis (e.g. dermoid cyst or endometrioma). The reference standard was the histology of the surgically removed adnexal tumors. Results A total of 1066 women were included, of whom 800 bad a benign mass and 266 a malignant mass. A specific diagnosis based on ultrasound findings was suggested in 899 (84%) tumors. The specificity was high for all diagnoses (range, 94-100%). The sensitivity was highest for benign teratoma/dermoid cysts (86%, 100/116), hydrosalpinges (86%, 18/21), peritoneal pseudocysts (80%, 4/5) and endometriomas (77%, 1531199), and lowest for functional cysts (17%, 4124), paraovarian/parasalpingeal cysts (14%, 3121), benign rare tumors (11%, 119), adenofibromas (8%, 3/39), simple cysts (6%, 1/18) and struma ovarii (0%, 0/5). The positive and negative likelihood ratios of pattern recognition with regard to dermoid cysts, hydrosalpinges and endometriomas were 68.2 and 0.14, 38.9 and 0.15, and 33.3 and 0.24, respectively. Dermoid cysts, hydrosalpinges, functional cysts, paraovarian cysts, peritoneal pseudocysts, fibromas/fibrothecomas and simple cysts were never misdiagnosed as malignancies by the ultrasound examiner, whereas more than 10% of inflammatory processes, adenofibromas and rare benign tumors including struma ovarii were misdiagnosed as malignancies. Conclusions Using subjective evaluation of gray-scale and Doppler ultrasound findings it is possible to make an almost conclusive diagnosis of a dermoid cyst, endometrioma and hydrosalpinx. Many other adnexal pathologies can be recognized but not confidently confirmed or excluded. Copyright (C) 2009 ISUOG. Published by John Wiley & Sons, Ltd.
|
|
