Auditory Cortical Plasticity in Patients with Single-Sided Deafness Before and After Cochlear Implantation.

PURPOSE: This study investigated neuroplastic changes induced by postlingual single-sided deafness (SSD) and the effects of a cochlear implantation for the deaf ear. Neural processing of acoustic signals from the normal hearing ear to the brain was studied before and after implantation using a positron emission tomography (PET)/CT scanner. METHODS: Eight patients with postlingual SSD received a cochlear implant (CI) in a prospective clinical trial. Dynamic imaging was performed in a PET/CT scanner using radioactively labeled water ([15O]H2O) to localize changes in the regional cerebral blood flow (rCBF) with and without an auditory task of logatomes containing speech-like elements without meaningful context. The normal hearing ear was stimulated before implantation and after the use of the cochlear implant for at least 8 months (mean 13.5, range 8.1-26.6). Eight age- and gender-matched subjects with normal hearing on both sides served as healthy control subjects (HCS). RESULTS: When the normal hearing ear of SSD patients was stimulated before CI implantation, the [15O]H2O-PET showed a more symmetrical rCBF in the auditory regions of both hemispheres in comparison to the HCS. The use of CI increased the asymmetry index (AI) in six of eight patients indicating an increase of activity of the contralateral hemisphere. Non-parametric statistics revealed a significant difference in the AI between patients before CI implantation and HCS (p < .01), which disappeared after CI implantation (p = .195). CONCLUSION: The functional neuroimaging data showed a tendency towards normalization of neuronal activity after CI implantation, which supports the effectiveness of CI in SSD patients. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT01749592, December 13, 2012.

The correlation between tinnitus-specific and quality of life questionnaires to assess the impact on the quality of life in tinnitus patients.

Introduction: Subjective tinnitus is often associated with a reduction in health-related quality of life (HRQoL). The HRQoL represents the impact of tinnitus on an individual's life by addressing the physical, social, and psychological domains of 1. A limited amount of studies has investigated the association between tinnitus and HRQoL questionnaires. The aim of this study was to examine the correlation between tinnitus-specific and HRQoL questionnaires in order to shorten fulfilling questionnaires, as it is often time-consuming. Material and method: Eighty-five patients with tinnitus as primary complaint completed five questionnaires, including one general, two tinnitus-specific, and two generic HRQoL questionnaires: Tinnitus Sample Case History Questionnaire (TSCHQ), Tinnitus Functional Index (TFI), Tinnitus Handicap Inventory (THI), short version of World Health Organization Quality of Life (WHOQOL-BREF), and the eight-item Short-Form (SF-8). Four simple linear regression models were used to analyze the relationship between the THI and TFI and the WHOQOL-BREF and SF-8. Results: A negative and strong correlation was found between the tinnitus questionnaires and the SF-8. More than half of the variability in the SF-8 scores could be explained by the TFI and THI, respectively 50.6 and 54.4% (all p < 0.001). A strong negative regression was also found between the WHOQOL-BREF and the THI and TFI with a decrease in the determination coefficient of approximately 10% compared with the SF-8. The weakest correlation (regression coefficient of 0.628, p < 0.001) was observed between the WHOQOL-BREF and the TFI, indicating that the WHOQOL-BREF mean score explained 39.4% of the TFI. When looking at the subdomain scores, a strong correlation was observed between the QoL subdomain of the TFI and a combination of the physical and psychological subdomain of the WHOQOL-BREF (r = -0.627, p < 0.001). Conclusion: The QoL subdomain of the TFI gives good information about the physical and psychological health. Thus, the TFI is suitable to assess both tinnitus severity and the HRQoL. The coefficients of determination of the WHOQOL-BREF were significantly lower compared to the SF-8, suggesting that the WHOQOL-BREF provides more specific information about HRQoL. If more specific information on HRQoL, such as "environment" and "social relationships", is required, it is recommended to use the WHOQOL-BREF.

Transcranial electric and acoustic stimulation for tinnitus: study protocol for a randomized double-blind controlled trial assessing the influence of combined transcranial random noise and acoustic stimulation on tinnitus loudness and distress.

BACKGROUND: Tinnitus is the result of aberrant neuronal activity. As a novel treatment form, neuromodulation is used to modify neuronal activity of brain areas involved in tinnitus generation. Among the different forms of electric stimulation, transcranial random noise stimulation (tRNS) has been shown to be a promising treatment option for tinnitus. In addition, recent studies indicate that the reduction in tinnitus can be more pronounced when different modalities of stimulation techniques are combined ("bimodal stimulation"). TRNS can be used in combination with acoustic stimulation (AS), a further treatment option recognized in the literature. The aim of the proposed study is to investigate whether simultaneous tRNS and AS improve levels of tinnitus loudness and distress. METHODS: The intervention consists of bilateral high-definition tRNS (HD-tRNS) over the auditory cortex combined with the application of AS which is studied in a crossover design. The visits will be performed in 26 sessions. There will be 20 treatment sessions, divided into two blocks: active and sham HD-tRNS. Within the blocks, the interventions are divided into group A: HD-tRNS and AS, and group B: HD-tRNS alone. Furthermore, in addition to the assessments directly following the intervention sessions, there will be six extra sessions performed subsequently at the end of each block, after a period of some days (follow-ups 1 and 2) and a month after the last intervention (C). Primary outcome measures are analog scales for evaluation of subjective tinnitus loudness and distress, and the audiological measurement of minimum masking level (MML). Secondary outcome measures are brain activity as measured by electroencephalography and standardized questionnaires for evaluating tinnitus distress and severity. DISCUSSION: To the best of our knowledge, this is the first study which uses HD-tRNS combined with AS for tinnitus treatment. The crossover design permits the comparison between HD-tRNS active vs. sham and with vs. without AS. Thus, it will be possible to evaluate the efficacy of the combined approach to HD-tRNS alone. In addition, the use of different objective and subjective evaluations for tinnitus enable more reliable and valid results. TRIAL REGISTRATION: Swiss Ethics Committee (BASEC-Nr. 2020-02027); Swiss Federal Complementary Database (kofam.ch: SNCTP000004051 ); and ClinicalTrials.gov (clinicaltrials.gov: NCT04551404 ).

Retrospective Investigation of Contralateral Hearing Thresholds of Patients With Sporadic Vestibular Schwannoma.

OBJECTIVE: The aim of this study was to investigate the contralateral hearing of patients with sporadic vestibular schwannoma (VS). STUDY DESIGN: Retrospective cohort study. SETTING: Pure-tone audiograms of the contralateral ear from patients with a wait-and-scan strategy were compared to the ones who received therapy. Due to a possible bias caused by the therapy, hearing thresholds before and after radiotherapy or surgery were compared separately with the wait-and-scan group. METHODS: From 1979 to 2017, 508 patients with sporadic VS could be included in the study. Of these, 240 received regular controls in the sense of wait-and-scan, 72 underwent radiotherapy (63 audiograms before and 43 after radiotherapy), and 196 had a surgery (186 audiograms before and 146 after surgery). Age-normalized hearing thresholds of the contralateral ear from patients with a wait-and-scan strategy were compared to ones who received therapy. In addition, hearing thresholds were compared to norm values. RESULTS: There was no evidence for a difference in the contralateral hearing of patients with sporadic VS between the wait-and-scan and therapy groups. The mean difference of hearing thresholds in our sample to norm values was found to be larger for the high frequencies and more pronounced in male patients. CONCLUSION: There was no evidence for a difference in the contralateral hearing loss of patients with sporadic VS between the wait-and-scan and therapy groups. However, there was some indirect indication of poorer contralateral hearing in all patients with sporadic VS compared to normative values.

[German-language versions of the Tinnitus Functional Index : Comparison of the two validated German-language versions of the Tinnitus Functional Index for Switzerland and Germany]. / Deutschsprachige Versionen des Tinnitus Functional Index : Vergleich der beiden validierten deutschsprachigen Versionen des Tinnitus Functional Index für die Schweiz und für Deutschland.

BACKGROUND: Two validated German-language versions of the Tinnitus Functional Index (TFI) exist, one for Switzerland and one for Germany. The TFI is considered to be a possible new standard questionnaire for evaluation of tinnitus severity and tinnitus treatment. OBJECTIVE: Considering the standardization taking place in tinnitus evaluation, our aim was to compare the two German-language TFI versions and to recommend only one TFI version in the German-speaking area. MATERIALS AND METHODS: The two German-language TFI versions were compared in a multicenter and randomized online questionnaire study with a crossover design. RESULTS: The total score of the two TFI versions did not differ in the total population. However, when further divided in terms of population and order of presentation of the TFI versions, there were significant differences in some cases, albeit with only moderate effect sizes. This suggests that the two versions are slightly different but still comparable. In factor analysis for the TFI version for Germany, in the entire population as well as in the Swiss population, six factors could be extracted. In contrast, for the German and Swiss TFI versions, only five factors could be extracted in the German population, and for the Swiss TFI version, only five factors in the Swiss population. CONCLUSION: The two German-language versions of the TFI are well comparable with each other. However, the factor analysis rather argues for use of the TFI version for Germany in the entire German-speaking region.

Cochlear implants in single-sided deafness - clinical results of a Swiss multicentre study.

AIM OF THE STUDY: The aim of this multicentre, prospective, open, nonrandomised clinical trial was to demonstrate the clinical efficiency and outcomes of cochlear implants (CIs) in adult patients with post-lingual single-sided deafness (SSD). METHODS: A group of five left and five right SSD participants were investigated with various clinical tests and questionnaires before and 12 months after CI activation. Changes in hearing thresholds, speech understanding in noise, sound localisation, tinnitus (Tinnitus Handicap Inventory; THI), subjective hearing ability (Speech, Spatial and Qualities of Hearing Scale; SSQ), and quality of life (WHOQOL-BREF) were assessed. In addition, the pre- and postoperative results of the SSD patients were compared with an age- and gender-matched normal hearing control group. RESULTS: Surgery was uncomplicated in all patients. Two years after implantation, 9 of the 10 patients used their CI regularly for an average of more than 11 hours a day. A significant improvement in speech understanding in noise measured in the sound field using the Oldenburg sentence test could be demonstrated in the two situations in which patients with SSD experience the greatest difficulty: speech from the front and noise at the healthy ear, and speech to the implanted ear and noise from the front. The sound localisation test showed significant improvement of the mean localisation error and the root mean square error after CI activation. Furthermore, a significant reduction of the THI was measured, and the SSQ showed a significant improvement in the subscale speech comprehension and in the subscale spatial hearing. Also, quality of life measured with the WHOQOL-BREF showed a general improvement, which was significant in the global subscale. For this questionnaire, there was no significant difference between the normal-hearing control group and the patients after 12 months of CI use. CONCLUSION: This study confirmed the clinical benefit of cochlear implantation in patients with SSD. The significant improvement of speech understanding in noise, sound localisation, tinnitus perception, subjective hearing ability, and in particular the improved quality of life support the recommendation that patients with recently acquired SSD should be offered a CI. (Clinical trial registration number on clinicaltrial.gov: NCT01749592).

The Influence of Cochlear Implantation on Tinnitus in Patients with Single-Sided Deafness: A Systematic Review.

OBJECTIVES: This systematic review provides an overview of the available studies (published by January 29, 2018) with descriptive data analysis about the influence of cochlear implantation on tinnitus in patients with single-sided deafness (SSD). DATA SOURCES: PubMed, EMBASE, Web of Science, Cochrane Library, and Google Scholar. REVIEW METHODS: Original studies about the influence of cochlear implantation on tinnitus, measured with different tinnitus questionnaires or visual analog scale, in patients with SSD were included. The pre- and postimplantation tinnitus scores of the included studies were extracted for the further systematic review. RESULTS: The systematic search yielded 1028 studies. After evaluating titles, abstracts, and full texts, 1011 of these were dismissed. From the remaining 17 studies, 4 showed a low directness of evidence or high risk of bias and were therefore excluded. Due to the nature of cochlear implantation in SSD, only cohort studies and no randomized trials exist, which limits the evaluation in a systematic review. Generally, the mean tinnitus questionnaire scores decreased after cochlear implantation in these 13 studies with a total of 153 patients. The most widely used tinnitus questionnaire was the Tinnitus Handicap Inventory. In these studies, 34.2% of patients demonstrated complete suppression, 53.7% an improvement, 7.3% a stable value, and 4.9% an increase of tinnitus, and none of the patients reported an induction of tinnitus. CONCLUSION: This review shows a clear improvement of tinnitus complaints after cochlear implantation in patients with SSD. Therefore, tinnitus might be considered as an additional indication for cochlear implantation in SSD.

Neuromodulation for tinnitus treatment: an overview of invasive and non-invasive techniques.

Tinnitus is defined as a perception of sound without any external sound source. Chronic tinnitus is a frequent condition that can affect the quality of life. So far, no causal cure for tinnitus has been documented, and most pharmacologic and psychosomatic treatment modalities aim to diminish tinnitus' impact on the quality of life. Neuromodulation, a novel therapeutic modality, which aims at alternating nerve activity through a targeted delivery of a stimulus, has emerged as a potential option in tinnitus treatment. This review provides a brief overview of the current neuromodulation techniques as tinnitus treatment options. The main intention is to provide updated knowledge especially for medical professionals counselling tinnitus patients in this emerging field of medicine. Non-invasive methods such as repetitive transcranial magnetic stimulation, transcranial electrical stimulation, neurofeedback, and transcutaneous vagus nerve stimulation were included, as well as invasive methods such as implanted vagus nerve stimulation and invasive brain stimulation. Some of these neuromodulation techniques revealed promising results; nevertheless, further research is needed, especially regarding the pathophysiological principle as to how these neuromodulation techniques work and what neuronal change they induce. Various studies suggest that individually different brain states and networks are involved in the generation and perception of tinnitus. Therefore, in the future, individually tailored neuromodulation strategies could be a promising approach in tinnitus treatment for achieving a more substantial and longer lasting improvement of complaints.

Modulation of K+ channel N-type inactivation by sulfhydration through hydrogen sulfide and polysulfides.

Fast N-type inactivation of voltage-gated K+ (Kv) channels is important in fine-tuning of cellular excitability. To serve diverse cellular needs, N-type inactivation is regulated by numerous mechanisms. Here, we address how reactive sulfur species-the gaseous messenger H2S and polysulfides-affect N-type inactivation of the mammalian Kv channels Kv1.4 and Kv3.4. In both channels, the H2S donor NaHS slowed down inactivation with varying potency depending on the "aging" of NaHS solution. Polysulfides were > 1000 times more effective than NaHS with the potency increasing with the number of sulfur atoms (Na2S2 < Na2S3 < Na2S4). In Kv1.4, C13 in the N-terminal ball domain mediates the slowing of inactivation. In recombinant protein exposed to NaHS or Na2S4, a sulfur atom is incorporated at C13 in the protein. In Kv3.4, the N terminus harbors two cysteine residues (C6, C24), and C6 is of primary importance for channel regulation by H2S and polysulfides, with a minor contribution from C24. To fully eliminate the dependence of N-type inactivation on sulfhydration, both cysteine residues must be removed (C6S:C24S). Sulfhydration of a single cysteine residue in the ball-and-chain domain modulates the speed of inactivation but does not remove it entirely. In both Kv1.4 and Kv3.4, polysulfides affected the N-terminal cysteine residues when assayed in the whole-cell configuration; on-cell recordings confirmed that polysulfides also modulate K+ channel inactivation with undisturbed cytosol. These findings have collectively identified reactive sulfur species as potent modulators of N-type inactivation in mammalian Kv channels.

Alexithymia Is Associated with Tinnitus Severity.

OBJECTIVE: Alexithymia is considered to be a personality trait with a tendency to express psychological distress in somatic rather than emotional form and, therefore, may play a vital role in somatization. Although, such a propensity can be found in patients suffering from tinnitus, the relationship between alexithymic characteristics and the subjective experience of tinnitus severity remains yet unclear. Our aim was to evaluate which alexithymic characteristics are linked to the subjective experience of tinnitus symptomatology. METHODS: We evaluated tinnitus severity (Tinnitus Handicap Inventory, THI), alexithymia (20-item Toronto Alexithymia Scale, TAS-20), and depression (Beck Depression Inventory, BDI) in 207 outpatients with tinnitus. Correlation analyses and multiple regression analyses were calculated in order to investigate the relationship between alexithymic characteristics, tinnitus severity, and depression. RESULTS: Highly significant positive correlations were found between THI total score and TAS-20 total score as well as BDI score. Regarding the TAS-20 subscales, multiple regression analyses showed that only the TAS-20 subscale "difficulty in identifying feelings" (DIF) and the BDI significantly predicted the subjective experience of tinnitus severity. Regarding the THI subscales, only higher scores of the THI subscale "functional" demonstrated an independent moderate association with higher scores for DIF. CONCLUSION: We found an independent association between the subjective experience of tinnitus severity and alexithymic characteristics, particularly with regard to limitations in the fields of mental, social, and physical functioning because of tinnitus and the difficulty of identifying feelings facet of alexithymia. These findings are conducive to a better understanding of affect regulation that may be important for the psychological adaptation of patients suffering from tinnitus.

Tinnitus functional index: validation of the German version for Switzerland.

BACKGROUND: Different standardized questionnaires are used to assess tinnitus severity, making comparisons across studies difficult. These questionnaires are also used to measure treatment-related changes in tinnitus although they were not designed for this purpose. To solve these problems, a new questionnaire - the Tinnitus Functional Index (TFI) - has been established. The TFI is highly responsive to treatment-related change and promises to be the new gold standard in tinnitus evaluation. The aim of the current study was to validate a German version of the TFI for a German-speaking population in Switzerland. METHODS: At the ENT department of the University Hospital Zurich, 264 subjects completed an online survey including the German version for Switzerland of TFI, Tinnitus Handicap Inventory (THI), Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI) and sociodemographic variables. Internal consistency of the TFI was calculated with Cronbach's alpha coefficient. Pearson correlation coefficients were used for the test-retest reliability of the TFI and to investigate convergent and discriminant validity between the THI and the BDI and BAI, respectively. Factor analysis was assessed using a principal component analysis with oblique rotation. The different factors extracted were then compared with the original questionnaire. RESULTS: The German version of the TFI for Switzerland showed an excellent internal consistency (Cronbach's alpha of 0.97) and an excellent test-retest reliability of 0.91. The convergent validity with THI was high (r = 0.86). The discriminant validity with BAI and BDI showed moderate results (BAI: r = 0.60 and BDI: r = 0.65). In the factor analysis only five factors with one main factor could be extracted instead of eight factors as described in the original version. Nevertheless, relations to the original eight subscales could be demonstrated. CONCLUSION: The German version of the TFI for Switzerland is a suitable instrument for measuring the impact of tinnitus. The reliability and validity of this version are comparable with the original version of the TFI. Although this study showed only five factors in the factor analysis, relations to the original eight subscales were identified. Therefore, the German version of the TFI for Switzerland can deliver relevant information regarding the different tinnitus domains. TRIAL REGISTRATION: Clinical trial registration number on clinicaltrial.gov: NCT01837368 .

Validation of PRISM (Pictorial Representation of Illness and Self Measure) as a novel visual assessment tool for the burden of suffering in tinnitus patients.

BACKGROUND: Chronic subjective tinnitus is a frequent condition that affects the subject's quality of life. The lack of objective measures of tinnitus necessitates the use of self-reporting and often time-consuming questionnaires for evaluating tinnitus severity. The Pictorial Representation of Illness and Self Measure (PRISM) is a two dimensional pictorial method to assess the burden of suffering. Patients illustrate their burden of suffering by the distance from a "self" to an illness circle, whereby a shorter distance indicates a higher burden of suffering. The aim of this prospective observational study was to validate the burden of suffering measured with PRISM in tinnitus patients by comparing it with different standardized questionnaires currently used in tinnitus evaluation. METHODS: A total of 188 patients filled out an online-based survey including sociodemographic variables and the following questionnaires: Tinnitus Handicap Inventory (THI), Tinnitus Questionnaire (TQ), WHO Quality of Life-Questionnaire (WHOQOL-BREF), and the Beck Depression Inventory (BDI). The subtle differences in the burden of suffering were accessed by using PRISM as an iPad version. Based on PRISM performance patients could easily be assigned in three groups, these being mildly, moderately, or severely affected akin to the standard questionnaires. RESULTS: The burden of suffering measured with PRISM correlated with the tinnitus severity (THI and TQ), depressive symptoms (BDI), and health related quality of life (WHOQOL-BREF) (all p ≤ 0.001). In the three PRISM groups tinnitus severity (THI and TQ), and depressive symptoms (BDI) differed significantly (all p ≤ 0.01). CONCLUSION: PRISM is an easily understood and time saving method for the assessment of burden of suffering in tinnitus patients. In daily clinical practice PRISM can help to identify patients with decompensated tinnitus that require more intensive treatment.

Which tinnitus-related characteristics affect current health-related quality of life and depression? A cross-sectional cohort study.

Tinnitus is sometimes associated with lower health-related quality of life (HRQoL) and depressive symptoms. However, only limited evidence exists identifying which tinnitus characteristics are responsible for these associations. The aim of this cross-sectional study was to assess associations between tinnitus, HRQoL, depressive symptoms, subjective tinnitus loudness and audiometrically assessed tinnitus characteristics (e.g., hearing threshold). Two hundred and eight outpatients reporting tinnitus completed questionnaires on tinnitus (Tinnitus Handicap Inventory, THI), HRQoL (World-Health-Organisation Quality of Life Short Form Survey, WHOQOL-BREF), and depressive symptoms (Beck Depression Inventory, BDI), and underwent audiometry. Patients with higher THI scores exhibited significantly lower HRQoL, and higher depression scores. THI total-score, THI subscales, and subjective tinnitus loudness explained significant variance of WHOQOL-BREF and BDI. Audiometrically measured features were not associated with WHOQOL-BREF or BDI. Overall, we confirmed findings that different features of tinnitus are associated with HRQoL and depressive symptoms but not with audiometrically assessed tinnitus characteristics. Consequently, physicians should evaluate THI total score, its sub-scores, and subjective tinnitus loudness to reliably and quickly identify patients who potentially suffer from depressive symptoms or significantly lower HRQoL. Supporting these patients early might help to prevent the development of reactive depressive symptoms and impairment of HRQoL.

Adhesion molecules close homolog of L1 and tenascin-C affect blood-spinal cord barrier repair.

Mice deficient in the recognition molecules, close homolog of L1 (CHL1) and tenascin-C, show improved and reduced functional recovery, respectively, after spinal cord injury compared with wild-type littermates. In this study, we addressed the question whether the differential functional outcome was paralleled by differences in blood-spinal cord barrier (BSCB) repair in the two mouse strains. We conducted spinal cord compression injuries in knock-out and wild-type mice. BSCB permeability was assessed by measuring the Evans blue spread within the spinal cord tissue at 14-21 days after injury. Results show that CHL1 reduces and tenascin-C enhances BSCB permeability, suggesting a correlation between functional outcome and BSCB repair.

Endoleaks after endovascular abdominal aortic aneurysm repair: detection with dual-energy dual-source CT.

PURPOSE: To assess the diagnostic performance of dual-energy dual-source computed tomography (CT) in the detection of endoleaks after endovascular abdominal aortic aneurysm (AAA) repair. MATERIALS AND METHODS: This study was local ethics board approved, and written informed consent was obtained from all patients. One hundred eighteen patients (21 women, 97 men; mean age, 74 years +/- 8 [standard deviation]) underwent follow-up dual-energy dual-source CT during the nonenhanced, arterial, and delayed phases after AAA repair. Delayed phase CT images were acquired in the dual-energy mode for reconstruction of virtual nonenhanced images. Two blinded and independent readers evaluated the data for the presence or absence of endoleaks during three reading sessions: Standard nonenhanced, arterial phase, and delayed phase images were read during session A; virtual nonenhanced, arterial phase, and delayed phase images, during session B; and virtual nonenhanced and delayed phase images, during session C. Sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) were calculated, with the session A image data set as the reference standard. Radiation dose parameters were estimated. RESULTS: Reading session A revealed that 52 (44%) of 118 patients had endoleaks. Overall sensitivity, specificity, NPV, and PPV for CT endoleak detection during sessions B and C were identical: 100%, 97%, 100%, and 96%, respectively. The accuracy of the session B and session C readings was not significantly different from that of the session A reading (P = .50). The effective radiation dose in the image acquisition protocol involving one dual-energy scan was significantly (P < .001) lower than the effective doses in the protocols involving standard triple-phase scanning (mean difference, 61%) and standard nonenhanced and delayed phase scanning (mean difference, 41%). CONCLUSION: Compared with standard protocols, one dual-energy dual-source CT scan performed during the delayed phase with reconstruction of virtual nonenhanced images enables detection of endoleaks after endovascular AAA repair with high accuracy and a considerably lower radiation dose.