Prognostic impact of MRI-derived feature tracking myocardial strain in patients with non-ischaemic dilated cardiomyopathy: a systematic review and meta-analysis.

AIM: To evaluate the clinical utility of feature tracking (FT)-derived myocardial strain in patients with non-ischaemic dilated cardiomyopathy (NIDCM). MATERIALS AND METHODS: Electronic database searches of PubMed, Web of Science Core Collection, Cochrane advanced search, and EMBASE were performed. Studies on NIDCM were divided into categories according to left ventricular ejection fraction (LVEF; <30%, 30-40%, >40%), and correlations between strains and prevalence of late gadolinium enhancement (LGE) were evaluated by weighted correlation coefficients. Global longitudinal strain (GLS) hazard ratios were also integrated for prediction of future adverse events. RESULTS: The present meta-analysis analysed data from 5,767 patients with NIDCM from 30 eligible studies. GLS and global circumferential strain significantly differed across the three LVEF categories (all p<0.05); however, global radial strain did not. Only GLS showed a strong correlation with the prevalence of LGE (Spearman's correlation coefficient = 0.61). The pooled HR of GLS for predicting adverse events was 1.15 (95% confidence interval [CI]: 1.07-1.23, p<0.001). CONCLUSION: In this meta-analysis, FT-derived GLS was strongly correlated with myocardial fibrosis and was an important predictor of future adverse events. These results suggest that FT-derived GLS may be useful in the pathological evaluation and risk stratification of NIDCM.

Value of 100 kVp scan with sinogram-affirmed iterative reconstruction algorithm on a single-source CT system during whole-body CT for radiation and contrast medium dose reduction: an intra-individual feasibility study.

AIM: To perform an intra-individual investigation of the usefulness of a contrast medium (CM) and radiation dose-reduction protocol using single-source computed tomography (CT) combined with 100 kVp and sinogram-affirmed iterative reconstruction (SAFIRE) for whole-body CT (WBCT; chest-abdomen-pelvis CT) in oncology patients. MATERIALS AND METHODS: Forty-three oncology patients who had undergone WBCT under both 120 and 100 kVp protocols at different time points (mean interscan intervals: 98 days) were included retrospectively. The CM doses for the 120 and 100 kVp protocols were 600 and 480 mg iodine/kg, respectively; 120 kVp images were reconstructed with filtered back-projection (FBP), whereas 100 kVp images were reconstructed with FBP (100 kVp-F) and the SAFIRE (100 kVp-S). The size-specific dose estimate (SSDE), iodine load and image quality of each protocol were compared. RESULTS: The SSDE and iodine load of 100 kVp protocol were 34% and 21%, respectively, lower than of 120 kVp protocol (SSDE: 10.6±1.1 versus 16.1±1.8 mGy; iodine load: 24.8±4versus 31.5±5.5 g iodine, p<0.01). Contrast enhancement, objective image noise, contrast-to-noise-ratio, and visual score of 100 kVp-S were similar to or better than of 120 kVp protocol. CONCLUSION: Compared with the 120 kVp protocol, the combined use of 100 kVp and SAFIRE in WBCT for oncology assessment with an SSCT facilitated substantial reduction in the CM and radiation dose while maintaining image quality.

Dual-layer detector CT of chest, abdomen, and pelvis with a one-third iodine dose: image quality, radiation dose, and optimal monoenergetic settings.

AIM: To compare the image quality and radiation dose of reduced iodine dose dual-layer detector (DL) computed tomography (CT) with those of a conventional 120 kVp protocol for chest-abdomen-pelvis CT (CAP-CT). MATERIALS AND METHODS: Forty patients with renal dysfunction (estimated glomerular filtrating ratio <45 ml/min/1.73 m2) underwent reduced iodine dose CAP-CT (120 kVp, 200 mg iodine/kg) on DLCT. Virtual monochromatic images (VMI) at 40-70 keV (5 keV interval) were reconstructed retrospectively. Forty matched patients who underwent conventional CAP-CT (120 kVp, 600 mg iodine/kg, iterative reconstruction) were included as controls. The size-specific dose estimate (SSDE), image noise, CT attenuation, and contrast-to-noise ratio (CNR) were compared between the protocols. Two radiologists rated image contrast, image noise, streak artefact, and diagnostic confidence on a five-point scale. RESULTS: The SSDE of the DLCT group was approximately 20% lower than that of the 120 kVp group (15.4±1.9 versus 19.4±2.3 mGy, p<0.01). DLCT-VMI provided almost constant image noise throughout the range of energies (differences of ≤13%), with the noise being equivalent or lower than 120 kVp in the abdomen. CT attenuation and CNR gradually increased as the energy decreased, with values comparable to 120 kVp being attained at around 45-50 keV. Although streak artefact was accentuated at 40-50 keV (p<0.01), the highest scores for diagnostic confidence were assigned at 40 and 45 keV, both of which were equivalent to 120 kVp (p=1.0). CONCLUSION: For CAP-CT with a one-third iodine dose, DLCT-VMI at 40-45 keV allows for a 20% reduction in radiation dose, while preserving image quality comparable to that of conventional 120 kVp protocol.

Low-dose abdominal CT: comparison of low tube voltage with moderate-level iterative reconstruction and standard tube voltage, low tube current with high-level iterative reconstruction.

AIM: To evaluate the quality of 100 kVp images with a hybrid iterative reconstruction algorithm level of 40% and 120 kVp (low-tube-current) images with a hybrid iterative reconstruction algorithm level of 60% in low-dose abdominal computed tomography (CT) using almost the same radiation dose. MATERIALS AND METHODS: This prospective study received institutional review board approval and written informed consent was obtained. One hundred and ten patients undergoing abdominal dynamic CT were randomly assigned to one of two protocols (100 and 120 kVp protocols). Radiation doses of the two protocols were almost identical. The 120 kVp images were post-processed with a hybrid iterative reconstruction algorithm level of 60% (i-120 kVp). The 100 kVp images were post-processed with a hybrid iterative reconstruction algorithm level of 40% (i-100 kVp). The effective dose (ED), image noise, CT attenuation, and signal-to-noise ratio (SNR) of the subcutaneous fat, muscle, liver, pancreas, and kidneys were compared between the protocols using Student's t-test. Qualitative analysis was also performed between the protocols. RESULTS: There were no significant differences in ED and SNR of any of the regions of interest (ROIs) between the protocols (p > 0.05). However, in the qualitative analysis, unnatural texture was significantly greater in the i-120 kVp than in the i-100 kVp protocol (p < 0.01). There were no other significant differences in the image quality between the protocols (p > 0.05). CONCLUSION: The combined use of low tube voltage and moderate-level iterative reconstruction techniques can be a more effective strategy for reducing patient radiation dose while attaining acceptable image quality than the use of standard tube voltage, low tube current with high-level iterative reconstruction.

Reduction in radiation and contrast medium dose via optimization of low-kilovoltage CT protocols using a hybrid iterative reconstruction algorithm at 256-slice body CT: phantom study and clinical correlation.

AIM: To optimize low-kilovoltage (kV) computed tomography (CT) protocols using a hybrid iterative reconstruction (HIR) algorithm at 256-detector-row body CT. MATERIALS AND METHODS: Based on preliminary phantom studies, three different tube voltage protocols with an equal contrast-to-noise ratio (CNR) were developed. They were a conventional 120 kV protocol with filtered back-projection (FBP), an 80 kV protocol with HIR (a 160% increase in the tube current-time product and a 40% reduction in the contrast medium dose), and a 100 kV protocol with HIR (a 20% reduction in the tube current-time product and the contrast medium dose). The clinical study included 70 patients (34 women, 36 men; mean age 70.5 ± 9.1 years, range 44-92 years) who had undergone CT at 120 kV a mean of 148 ± 137 days before undergoing low kV contrast-enhanced body CT (80 kV with HIR, n = 35; 100 kV with HIR, n = 35). The estimated effective radiation dose (ED), image noise, and CNR were calculated and the visual image quality was scored on a four-point scale. RESULTS: Mean ED was 12.3, 8.4, and 15.4 mSv for the 80, 100, and 120 kV protocol, respectively, and significantly lower using the low kV protocols. There was no significant difference in the image noise and CNR between the low kV protocols with HIR and the 120 kV protocol with FBP, or in the visual scores among the three protocols. CONCLUSION: Without ensuing image-quality degradation, the radiation and contrast medium dose can be reduced with optimal contrast-enhanced CT protocols using a low kV technique and an HIR algorithm.

Detection of small pulmonary nodules on chest radiographs: efficacy of dual-energy subtraction technique using flat-panel detector chest radiography.

AIM: To investigate the effect of a double-exposure dual-energy subtraction (DES) technique on the diagnostic performance of radiologists detecting small pulmonary nodules on flat-panel detector (FPD) chest radiographs. MATERIALS AND METHODS: Using FPD radiography 41 sets of chest radiographs were obtained from 26 patients with pulmonary nodules measuring

Diagnostic Significance of Cortical Superficial Siderosis for Alzheimer Disease in Patients with Cognitive Impairment.

BACKGROUND AND PURPOSE: Because the diagnostic significance of cortical superficial siderosis for Alzheimer disease and the association between cortical superficial siderosis and the topographic distribution of cerebral microbleeds have been unclear, we investigated the association between cortical superficial siderosis and clinicoradiologic characteristics of patients with cognitive impairment. MATERIALS AND METHODS: We studied 347 patients (217 women, 130 men; mean age, 74 ± 9 years) who visited our memory clinic and underwent MR imaging (3T SWI). We analyzed the association between cortical superficial siderosis and the topographic distribution of cerebral microbleeds plus clinical characteristics including types of dementia. We used multivariate logistic regression analysis to determine the diagnostic significance of cortical superficial siderosis for Alzheimer disease. RESULTS: Twelve patients (3.5%) manifested cortical superficial siderosis. They were older (P = .026) and had strictly lobar cerebral microbleeds significantly more often than did patients without cortical superficial siderosis (50.0% versus 19.4%, P = .02); the occurrence of strictly deep and mixed cerebral microbleeds, however, did not differ in the 2 groups. Alzheimer disease was diagnosed in 162 (46.7%) patients. Of these, 8 patients (4.9%) had cortical superficial siderosis. In the multivariate logistic regression analysis for the diagnosis of Alzheimer disease, lacunar infarcts were negatively and independently associated with Alzheimer disease (P = .007). CONCLUSIONS: Although cortical superficial siderosis was associated with a strictly lobar cerebral microbleed location, it was not independently associated with Alzheimer disease in a memory clinic setting. Additional studies are required to investigate the temporal changes of these cerebral amyloid angiopathy-related MR imaging findings.

MR of denervated tongue: temporal changes after radical neck dissection.

PURPOSE: The purpose of this study was to evaluate the temporal changes of MR imaging in the denervated tongue after a radical neck dissection. METHODS: One hundred seventy-four consecutive MR studies in 116 patients with radical neck dissections for malignant tumors of the head and neck were evaluated retrospectively. Patients with tumors involving the tongue or hypoglossal nerve were not included in this study. RESULTS: Abnormal signal intensity and/or hemiatrophy on the side of the tongue operated on was seen in 22 patients who had hypoglossal paralysis after radical neck dissection. The denervated side of the tongue appeared hypointense to hyperintense relative to the normal side on T1-weighted images and hyperintense on T2-weighted images. Signal intensity ratios of the abnormal to normal muscles were 0.9-1.6 on T1-weighted images and 1.3-2.8 on T2-weighted images. High signal intensity on T1-weighted images appeared 5 months or more after the dissection, whereas on T2-weighted images, the most prominent increases in signal intensity appeared in the first several months after denervation. Hemiatrophy of the tongue was observed on MR images obtained more than 6 months after surgery. CONCLUSION: MR findings in the denervated tongue are compatible with histologic changes and are characterized by an enlarged extracellular fluid space or fatty infiltration. The pattern of signal intensity and the degree of hemiatrophy suggest the duration of denervation.

Comparison of dynamic contrast-enhanced 3T MR and 64-row multidetector CT angiography for the localization of spinal dural arteriovenous fistulas.

BACKGROUND AND PURPOSE: For the localization of spinal dural arteriovenous fistulas, it is not determined whether dynamic contrast-enhanced MRA is more reliable than multidetector CTA. The aim of this study was to compare the agreement between intra-arterial DSA, dynamic contrast-enhanced MRA at 3T, and 64-row multidetector CTA for the localization of spinal dural arteriovenous fistulas. MATERIALS AND METHODS: We enrolled 12 consecutive patients (11 men, 1 woman; age range, 46-83 years; mean, 65 years) who underwent preoperative dynamic contrast-enhanced MRA at 3T and 64-row multidetector CTA. The spinal dural arteriovenous fistula location was confirmed by intra-arterial DSA as the reference standard. Two reviewers independently evaluated the level of the artery feeding the spinal dural arteriovenous fistula on the basis of continuity between the feeder and abnormal spinal vessels on 3T dynamic contrast-enhanced MRA and 64-row multidetector CTA images. Interobserver and intermodality agreement was determined by calculation of the κ coefficient. RESULTS: On DSA, the vessel feeding the spinal dural arteriovenous fistula was the intercostal artery (7 cases), the lumbar artery (3 cases), and the internal iliac artery or the ascending pharyngeal artery (1 case each). For the fistula level, interobserver agreement was excellent for 3T dynamic contrast-enhanced MRA (κ = 0.97; 95% CI, 0.92-1.00) and very good for 64-row multidetector CTA (κ = 0.84; 95% CI, 0.72-0.96). Intermodality agreement with DSA was good for 3T dynamic contrast-enhanced MRA (κ = 0.78; 95% CI, 0.49-1.00) and moderate for 64-row multidetector CTA (κ = 0.41; 95% CI, 0.020-0.84). CONCLUSIONS: For the localization of spinal dural arteriovenous fistulas, 3T dynamic contrast-enhanced MRA may be more reliable than 64-row multidetector CTA.

Prevalence and topography of small hypointense foci suggesting microbleeds on 3T susceptibility-weighted imaging in various types of dementia.

BACKGROUND AND PURPOSE: The prevalence and topography of small hypointense foci suggesting microbleeds on 3T SWI in various types of dementia have not been systematically investigated. The purpose of this study was to determine the prevalence and topography of SHF on 3T SWI in patients with different dementia subtypes. MATERIALS AND METHODS: We included 347 consecutive patients (217 women, 130 men; age range, 42-93 years; mean age, 74 years) who attended our memory clinic and underwent 3T SWI. They were divided into 6 groups: subjective complaints, MCI, AD, DLB, VaD, and FTLD. Two neuroradiologists evaluated the number and location of SHF on SWIs. Statistical analyses were performed to evaluate inter- and intragroup differences. RESULTS: Of the 347 patients, 160 (46.1%) exhibited at least 1 small hypointense focus. This was true in 86% with VaD, 54% with DLB, 48% with AD, 41% with MCI, 27% with FTLD, and 22% with subjective complaints. With the subjective complaints group as a reference, the odds ratio adjusted by age, sex, and arterial hypertension was 9.2 (95% CI, 2.0-43.6) for VaD; 5.4 (95% CI, 1.2-24.3) for AD; 3.1 for DLB (95% CI, 1.1-8.8); 2.0 for MCI (95% CI, 0.5-8.1); and 1.5 for FTLD (95% CI, 0.4-5.4). There was a significant lobar predilection for AD, DLB, and FTLD groups (P < .05). CONCLUSIONS: On 3T SWI, patients with VaD, AD, and DLB manifested a high SHF prevalence. In patients with AD, DLB, and FTLD, the SHF exhibited a lobar predilection.

Quantitative blood flow measurements in gliomas using arterial spin-labeling at 3T: intermodality agreement and inter- and intraobserver reproducibility study.

BACKGROUND AND PURPOSE: QUASAR is a particular application of the ASL method and facilitates the user-independent quantification of brain perfusion. The purpose of this study was to assess the intermodality agreement of TBF measurements obtained with ASL and DSC MR imaging and the inter- and intraobserver reproducibility of glioma TBF measurements acquired by ASL at 3T. MATERIALS AND METHODS: Two observers independently measured TBF in 24 patients with histologically proved glioma. ASL MR imaging with QUASAR and DSC MR imaging were performed on 3T scanners. The observers placed 5 regions of interest in the solid tumor on rCBF maps derived from ASL and DSC MR images and 1 region of interest in the contralateral brain and recorded the measured values. Maximum and average sTBF values were calculated. Intermodality and intra- and interobsever agreement were determined by using 95% Bland-Altman limits of agreement and ICCs. RESULTS: The intermodality agreement for maximum sTBF was good to excellent on DSC and ASL images; ICCs ranged from 0.718 to 0.884. The 95% limits of agreement ranged from 59.2% to 65.4% of the mean. ICCs for intra- and interobserver agreement for maximum sTBF ranged from 0.843 to 0.850 and from 0.626 to 0.665, respectively. The reproducibility of maximum sTBF measurements obtained by methods was similar. CONCLUSIONS: In the evaluation of sTBF in gliomas, ASL with QUASAR at 3T yielded measurements and reproducibility similar to those of DSC perfusion MR imaging.

Popliteal artery entrapment syndrome: non-invasive diagnosis by MDCT and MRI.

We present a case of a 19-year-old male patient complaining of right leg pain, which appeared after exercise and abated with rest. Computed tomography (CT) and magnetic resonance angiography (MRA) showed occlusion of right popliteal artery. Volume rendering CT image showed not only occlusion of right popliteal artery but also abnormal course of the medial head of the gastrocnemius muscle (MHG). CT and MR images of right popliteal fossa showed the abnormal anatomy that MHG coursed between popliteal artery with thrombus and popliteal vein. Popliteal artery entrapment syndrome was diagnosed non-invasively by multidetector CT and MRI. Sectional radiological and three-dimensional images are useful for not only depiction of the arterial changes but also identification of the abnormal anatomic structures responsible for the entrapment.

Balloon-occluded retrograde transvenous embolization of a pelvic arteriovenous malformation.

We successfully performed embolization therapy for a pelvic arteriovenous malformation by the retrograde transvenous approach using a liquid embolic material. This malformation was unique in that it had a single draining vein, which allowed this technique employing an occlusion balloon.