Radiation Induced DNA Double-Strand Breaks in Radiology.

UNLABELLED: Shortly after the discovery of X-rays, their damaging effect on biological tissues was observed. The determination of radiation exposure in diagnostic and interventional radiology is usually based on physical measurements or mathematical algorithms with standardized dose simulations. γ-H2AX immunofluorescence microscopy is a reliable and sensitive method for the quantification of radiation induced DNA double-strand breaks (DSB) in blood lymphocytes. The detectable amount of these DNA damages correlates well with the dose received. However, the biological radiation damage depends not only on dose but also on other individual factors like radiation sensitivity and DNA repair capacity. Iodinated contrast agents can enhance the x-ray induced DNA damage level. After their induction DSB are quickly repaired. A protective effect of antioxidants has been postulated in experimental studies. This review explains the prinicple of the γ-H2AX technique and provides an overview on studies evaluating DSB in radiologic examinations. KEY POINTS: Radiologic examinations including CT and angiography induce DNA double-strand breaks. Even after mammography a slight but significant increase is detectable in peripheral blood lymphocytes. The number of radiation induced double-strand breaks correlates well with the radiation dose. Individual factors including radiation sensitivity, DNA repair capacity and the application of iodinated contrast media has an influence on the DNA damage level.

iPads in Breast Imaging - A Phantom Study.

Introduction: Modern tablet PCs as the iPad are becoming more and more integrated into medicine. The aim of this study was to evaluate the display quality of iPads regarding digital mammography. Materials and Methods: Three experienced readers compared the display quality of the iPad 2 and 3 with a dedicated 10 megapixel (MP) mammography liquid crystal display (LCD) screen in consensus using the standardized Contrast Detail Mammography (CDMAM) phantom. Phantom fields without agreement between the readers were classified as "uncertain", correct 2 : 1 decisions were classified as "uncertain/readable". In a second step display quality of the three reading devices was judged subjectively in a side by side comparison. Results: The 10 MP screen was superior to both iPads in 4 (phantom-)fields and inferior in 2 fields. Comparing the iPads, version 3 was superior in 4 fields and version 2 was superior in 1 field. However these differences were not significant. Total number of "uncertain" fields did not show significant differences. The number of "uncertain" fields was 15 with the 10 MP screen, 16 with the iPad 2 and 17 with the iPad 3 (p > 0.05), the number of "uncertain/readable" fields was 4, 7 and 8, respectively. Subjective image quality of the iPad 3 and the 10 MP screen was rated superior to the iPad 2. Conclusion: The evaluated iPads, especially in version 3, seem to be adequate to display mammograms in a diagnostic quality and thus could be useful e.g. for patient consultation, clinical demonstration or educational and teaching purposes. However primary mammogram reading should still be performed on dedicated large sized reading screens.

Comparison of 128-section single-shot technique with conventional spiral multisection CT for imaging of the temporal bone.

BACKGROUND AND PURPOSE: Computed tomography is an essential modality for imaging of the temporal bone. Newest generation scanners allow the coverage of large examination volumes with a single gantry rotation. The objective of this study was to compare a 128-section SST (1 single rotation of the x-ray tube) with conventional spiral MSCT (ultra-high-resolution mode) for imaging of the temporal bone. MATERIALS AND METHODS: Fifty-four temporal bones in 27 patients were scanned with both a conventional MSCT and 128-section SST. After blinding and randomization of both examinations, 2 observers assessed the visualization of 38 anatomic structures (eg, various segments of the facial nerve canal, mallear ligaments) by using multiplanar reconstructions in the axial and coronal planes. The differences in evaluation scores obtained for the 2 techniques were analyzed by using a Wilcoxon signed rank test, with a P value of < .05 considered significant. For both methods, imaging time and radiation exposure were noted. RESULTS: Overall visualization of anatomic structures did not differ significantly between the 2 techniques (P > .05). When we compared the anatomic structures separately, there was better visualization of the lateral mallear ligament with MSCT, whereas the cochlear septa were ranked higher with SST (P < .05). Imaging time and average DLP for MSCT were 12.3 seconds and 306 mGy cm, respectively; for SST, values they were 1 second and 64 mGy cm, respectively (ie, a dose reduction of 79%). CONCLUSIONS: For imaging of the temporal bone with adequate diagnostic quality, 128-section SST can be used. The main advantages over MSCT are the dramatic reductions of imaging time and radiation exposure, which are particularly important when scanning uncooperative patients or children.

Accuracy of radiological tumour size assessment and the risk for re-excision in a cohort of primary breast cancer patients.

BACKGROUND: Re-operations after breast conserving surgery (BCS) are necessary, when specimen margins are not free of breast cancer cells. This study explored the accuracy of preoperative tumour size assessment and its influence on the rate of re-excisions and mastectomies. METHODS: The study included 1591 patients with invasive breast cancer, who were planned for BCS. Patient, staging and tumor characteristics were evaluated concerning their influence on re-excision and mastectomy rates. Patient and tumor characteristics comprised histopathological tumour size, HER2 status, multifocality, in situ component, grading (G), nodal status and hormone receptor (HR) status. Staging characteristics included deviation from pathological tumour size as measured by clinical examination, sonography and mammography. RESULTS: In 1316 patients (83%) sufficient treatment was possible with one operation. 275 patients (17%) had to undergo at least one further surgery as a result of positive specimen margins. In 138 patients (9%) mastectomy was ultimately necessary. In patients with a positive HER2 status, a larger tumour size, underestimation by ultrasound, an in situ component and multifocality, the risk for a re-operation was about doubled. Tumour size deviation in the mammogram or the clinical tumour size assessment did not have significant influence to the re-excision rates. CONCLUSION: Tumour size and accurate presurgical assessment of the tumour size itself are independent predictors for the need of a second surgery or even a mastectomy in patients for whom a primary BCS was planned.

[A useful tool for routine radiological examinations : the iPhone application "KM Helper"]. / Sinnvoller Einsatz neuer elektronischer Medien bei radiologischen Untersuchungen : Die iPhone-Applikation "KM Helper"

Since Apple's iPhone revolutionized the smartphone market, numerous software application features (apps) for portable devices have been developed. Amongst many others, a broad range of medical assistance software, such as anatomic books or medical encyclopedias is now available. We developed an app which helps to identify patients who need medical treatment before intravenous or intra-arterial administration of iodinated contrast media. The purpose of this article is to show that novel techniques such as smartphone applications can be a useful tool in medicine.

New diagnostic criteria in real-time elastography for the assessment of breast lesions.

PURPOSE: Elastography is a new ultrasonographic method that has been examined as a diagnostic tool for breast lesions. This study was intended to create and define new elastographic criteria allowing assessment of whether breast lesions are malignant or benign. MATERIALS AND METHODS: 217 patients with a total of 245 breast lesions of unknown malignancy underwent ultrasound examination. The new eSie Touch Elasticity Imaging technology (Siemens, Erlangen, Germany) was used with a 10-MHz linear transducer (Acuson Antares). Lesions were examined using B-mode and real-time elastography (RTE). Each lesion was histologically assessed by core biopsy. Five RTE characteristics were examined: elasticity proportion (EP), different location on RTE in comparison with B-mode (MV), different contrast patterns (SOS), dorsal lesion limitation visibility and different size on RTE in comparison with B-mode. RESULTS: 54 malignant lesions (54 %) appeared inelastic, in contrast to the benign control group (34.5 %; P = 0.001). A completely elastic pattern was visible in 10 malignant (10 %) and 39 benign lesions (26.9 %). MV was identified in 23 cases, with 22 of the lesions being malignant and one benign. The SOS was negative in 89 malignant lesions (89 %) and positive in 100 benign lesions. The dorsal lesion limitation was visible on RTE without B-mode in 88 malignant lesions (88 %) and 27 benign lesions (18.6 %). The size was assessed as larger in 45 malignant lesions (45 %) and seven benign lesions (4.8 %). CONCLUSION: SOS and a larger tumor size on RTE are specific characteristics of malignant breast lesions. EP, MV and distal mass border are further helpful signs to assess the malignancy of tumors.

Effect of CT scan protocols on x-ray-induced DNA double-strand breaks in blood lymphocytes of patients undergoing coronary CT angiography.

AIMS: To compare in vivo DNA lesions induced during helical and sequential coronary computed tomography angiography (CTA) and to evaluate the effect of CT parameters on double-strand break (DSB) levels. METHODS: Thirty-six patients were examined with various CT protocols and modes (helical scan, n = 27; sequential scan, n = 9) either using a 64-slice dual-source or a 128-slice CT system. Blood samples were obtained before and 30 min after CT. Lymphocytes were isolated, stained against the phosphorylated histone variant γ-H2AX, and DSBs were visualised by using fluorescence microscopy. RESULTS: DSB yields 30 min after CTA ranged from 0.04 to 0.71 per cell and showed a significant correlation to DLP (ρ = 0.81, p < 0.00001). Median DSB yield and median DLP were significantly lower after sequential compared to helical CT examinations (0.11 vs. 0.37 DSBs/cell and 249 vs. 958 mGy cm, p < 0.00001). Additional calcium scoring led to an increase in DLP (p = 0.15) and DSB levels (p = 0.04). DSB levels normalised to the DLP showed a significant correlation to the attenuation of the blood (ρ = 0.53, p = 0.01) and a negative correlation to the body mass index of the patients (ρ = -0.37, p = 0.06). CONCLUSION: γ-H2AX immunofluorescence microscopy allows one to determine dose-related effects on x-ray-induced DSB levels and to consider individual factors which cannot be monitored by physical dose measurements.

Peripheral intravenous power injection of iodinated contrast media through 22G and 20G cannulas: can high flow rates be achieved safely? A clinical feasibility study.

PURPOSE: Modern examination protocols for computed tomography (CT) often require high injection rates of iodinated contrast media (CM). The purpose of this study was to evaluate the maximum achievable flow rates and stability of different peripheral intravenous catheters (IVC) in vitro and to assess the feasibility of higher injection rates through small IVC in vivo. MATERIALS AND METHODS: For in vitro experiments flow measurements followed by high pressure testing of different types of IVC (22, 20, and 18 gauge [G]) were performed. For the in vitro study 91 patients with already inserted 22 or 20G IVC who had been referred for CT received Iopamidol (300 mg iodine/ml) at flow rates between 2 and 5 ml/sec. Complications were documented. RESULTS: The maximal achievable flow rate of the tested IVC in vitro ranged from 5 to 8 ml/sec. No damage was observed during in vitro testing. The initially targeted in vivo flow rate was dropped in 33 of 91 (36 %) patients because the IVC could not be flushed adequately with saline before CM injection. Extravasation of CM occurred in 2 cases. In the remaining 58 patients the standard CT protocol was performed with flow rates of 3 ml/sec through 22G IVC and 5 ml/sec through 20G IVC, respectively. In this group, the extravasation of CM was observed twice (p > 0.05). CONCLUSION: Even with highly viscous CM, high flow rates can be applied in vitro in 22, 20, and 18G IVC without risking material damage. In vivo power injection of iodinated CM through 22G and 20G IVC seems to be safely achievable in the majority of patients with flow rates of up to 3 ml/sec and 5 ml/sec. Extravasation rates do not differ significantly between patients with high-flow or low-flow injections.

[X-ray-induced DNA double-strand breaks after angiographic examinations of different anatomic regions]. / Strahleninduzierte DNA-Doppelstrangbrüche nach Angiografien verschiedener Körperregionen.

PURPOSE: The aim of this study was to investigate DNA double-strand breaks (DSBs) in blood lymphocytes as markers of the biological radiation effects in angiography patients. MATERIALS AND METHODS: The method is based on the phosphorylation of the histone variant H 2AX (gamma-H2AX) after formation of DSBs. Blood samples were collected before and up to 24 hours after exposure of 31 patients undergoing angiographies of different body regions. Blood lymphocytes were isolated, fixed, and stained with a specific gamma-H2AX antibody. Distinct foci representing DSBs were enumerated using fluorescence microscopy. Additional in-vitro experiments (10 - 100 mGy) were performed for evaluation of DBS repair. RESULTS: 15 minutes after the end of fluoroscopy values between 0.01 and 1.50 DSBs per cell were obtained. The DNA damage level normalized to the dose area product was 0.099 (cardiac angiographies), 0.053 (abdominal angiographies), 0.023 (pelvic/leg angiographies) and 0.004 excess foci/cell/mGym (2) (cerebrovascular angiographies). A linear correlation was found between gamma-H2AX foci levels and the dose area product (abdomen: R (2) = 0.96; pelvis/legs: R 2 = 0.71). In-vivo on average 46 % of DSBs disappeared within 1 hour and 70 % within 2.5 hours. CONCLUSION: gamma-H2AX immunofluorescence microscopy is a sensitive and reliable method for the determination of X-ray-induced DSBs during angiography. The DNA damage level depends on the dose, the exposed anatomic region, and the duration/fractionation of the X-ray exposure.

Automated breast ultrasound: lesion detection and BI-RADS classification--a pilot study.

PURPOSE: Evaluation of an automated breast ultrasound system (ABUS) regarding the detection and classification of breast lesions according to BI-RADS. MATERIALS AND METHODS: Women were selected for the study who had unclear findings in breast diagnosis performed elsewhere (palpation, sonography or mammography) and who were referred for further work-up. All patients received a hand-held ultrasonography (HHUS) with a 13 MHz transducer, clinical examination and mammography of both breasts. Additionally, the affected breast received the ABUS (SomoVuTM, U-Systems, Inc., San Jose, CA, USA; EC Representative: Siemens, Erlangen, Germany) which was performed with an 8 MHz transducer. Five radiologists independently evaluated the ABUS images regarding lesion detectability. All detected lesions were classified according to BI-RADS assessment. The examiners had no knowledge of the patients' clinical examination or of the result of the mammography or the HHUS. Results of the ABUS were compared to HHUS. RESULTS: 35 women were included in the study. 25 BI-RADS 4 or 5 lesions had further histological (n = 23) or cytological (n = 2) work-up which revealed 13 malignant and 12 benign findings. The size of all lesions ranged from 6 to 32 mm (median 14 mm). With the ABUS all examiners detected 29 to 30 lesions while HHUS revealed 30 lesions. One suspicious area in HHUS was not reported by any of the five examiners with the ABUS. Histology of this area revealed mastopathic disease. No benign lesion was classified as BI-RADS 5 with the ABUS or HHUS. All breast cancers were found with the ABUS by all examiners and correctly classified as BI-RADS 4 or 5. There was good agreement regarding BI-RADS classification of HHUS and ABUS for the five different examiners with Kappa values between 0.83 and 0.87. CONCLUSION: These preliminary results show that the ABUS allows detection of solid and cystic lesions and their BI-RADS classification with a high reliability in a selected patient group.

Cutaneous application of local anaesthetic--a useful help in galactography.

Galactography is an important step in the diagnostic workup of abnormal nipple discharge. At times it is impossible to insert the cannula in the secreting duct and galactography cannot be performed. In such cases we tried applying local anaesthetic spray (LA) cutaneously to the nipple followed by a further insertion attempt. LA has enabled us to insert the galactography cannula in all patients so far. We concluded that after previous unsuccessful attempts, the presented technique may relax the duct orifice and therefore permit insertion of the galactography cannula into the secreting duct.

Epiphyseal injuries in the growing athlete.

The epiphyses and epiphyseal plates are vital structures in the bone development of the growing athlete. The epiphyseal plate is two to five times weaker than the surrounding fibrous tissue in children and adolescents; consequently a force causing a ligamentous tear in adults is likely to cause an epiphyseal plate injury in growing children. Two types of epiphyseal injury that are common in the growing athlete are (a) separation across the epiphyseal plate, which is usually produced by a direct blow to the joint area or by a strong muscular contraction, and (b) traumatic epiphysitis, the more common of the two, which is usually caused by strong, repetitive contraction of a muscle attached to a traction epiphysis. Each epiphyseal site has specific anatomic features and the forces causing injury differ slightly at each site. An improperly treated separation of an intra-articular pressure epiphysis can have a disastrous effect on the proper functioning of the normally well-fitted articulation of bone ends in the joint. Consequently, proper diagnosis and treatment are essential. Traumatic epiphysitis can result in chronic inflammation or fragmentation, or both, if the condition is not arrested. Therefore the athlete must discontinue the activities that are causing the trauma until the inflammation is completely arrested. Absolute rest may even be required.