Non-contrast free-breathing 2D CINE compressed SENSE T1-TFE cardiovascular MRI at 3T in sedated young children for assessment of congenital heart disease

Cardiac MRI is a crucial tool for assessing congenital heart disease (CHD). However, its application remains challenging in young children when performed at 3T. The aim of this retrospective single center study was to compare a non-contrast free-breathing 2D CINE T1-weighted TFE-sequence with compressed sensing (FB 2D CINE CS T1-TFE) with 3D imaging for diagnostic accuracy of CHD, image quality, and vessel diameter measurements in sedated young children. FB 2D CINE CS T1-TFE was compared with a 3D non-contrast whole-heart sequence (3D WH) and 3D contrast-enhanced MR angiography (3D CE-MRA) at 3T in 37 CHD patients (20♂, 1.5±1.4 years). Two radiologists independently assessed image quality, type of CHD, and diagnostic confidence. Diameters and measures of contrast and sharpness of the aorta and pulmonary vessels were determined. A non-parametric multi-factorial approach was used to estimate diagnostic accuracy for the diagnosis of CHD. Linear mixed models were calculated to compare contrast and vessel sharpness. Krippendorff's alpha was determined to quantify vessel diameter agreement. FB 2D CINE CS T1-TFE was rated superior regarding image quality, diagnostic confidence, and diagnostic sensitivity for both intra- and extracardiac pathologies compared to 3D WH and 3D CE-MRA (all p<0.05). FB 2D CINE CS T1-TFE showed superior contrast and vessel sharpness (p<0.001) resulting in the highest proportion of measurable vessels (740/740; 100%), compared to 3D WH (530/620; 85.5%) and 3D CE-MRA (540/560; 96.4%). Regarding vessel diameter measurements, FB 2D CINE CS T1-TFE revealed the closest inter-reader agreement (Krippendorff's alpha: 0.94-0.96; 3D WH: 0.78-0.94; 3D CE-MRA: 0.76-0.93). FB 2D CINE CS T1-TFE demonstrates robustness at 3T and delivers high-quality diagnostic results to assess CHD in sedated young children. Its ability to function without contrast injection and respiratory compensation enhances ease of use and could encourage widespread adoption in clinical practice.

Longitudinal follow-up by MR angiography reveals progressive dilatation of the distal aorta after aortic root replacement in Marfan syndrome

OBJECTIVES

To define and compare growth rates of the distal aorta in Marfan patients with and without aortic root replacement using serial MR angiography (MRA).

METHODS

We retrospectively included 136 Marfan patients with a total of 645 MRAs who underwent a median of five MRAs (range: 2-13) at 1.5 T and 3 T in annual intervals. Of these, 41 patients (34.8 ± 12 years) had undergone aortic root replacement. The remaining 95 patients (29.0 ± 17 years) still had a native aorta and served as the control group. Thoracic aortic diameters were independently measured at eleven predefined levels. Estimated growth rates were calculated using a mixed effects model adjusted for sex, age, BMI, and medication.

RESULTS

Marfan patients with aortic root replacement revealed the highest mean estimated growth rate in the proximal descending aorta (0.77 mm/year, CI: 0.31-1.21). Mean growth rates at all levels of the distal thoracic aorta were significantly higher in patients with aortic root replacement (0.28-0.77 mm/year) when compared to patients without aortic root replacement (0.03-0.07 mm/year) (all p < 0.001). Antihypertensive medication, gender, and BMI had no significant impact on the distal aortic growth rates.

CONCLUSION

Distal thoracic aortic diameters increase at a significantly higher rate in Marfan patients with aortic root replacement compared to Marfan patients without aortic root replacement. Further studies are warranted to investigate if the increased growth rate of the distal thoracic aorta after aortic root replacement is caused by altered hemodynamics due to the rigid aortic root graft or due to the general genetic disposition of post-operative Marfan patients.

CLINICAL RELEVANCE STATEMENT

High growth rates of the distal aorta after aortic root replacement underline the need for careful life-long aortic imaging of Marfan patients after aortic root replacement.

KEY POINTS

• Aortic growth rates in Marfan patients with aortic root replacement are highest in the mid-aortic arch, the proximal- and mid-descending aorta. • Growth rates of the distal thoracic aorta are significantly higher in Marfan patients with aortic root replacement compared to Marfan patients without aortic root replacement. • Antihypertensive medication, gender, and BMI have no significant impact on distal aortic growth rates in Marfan patients.

Comparison of cine cardiac magnetic resonance and echocardiography derived diameters of the aortic root in a large population-based cohort

Transthoracic echocardiography (TTE) and cine cardiac magnetic resonance imaging (CMR) are established imaging methods of the aortic root. We aimed to evaluate the comparability of measurements in TTE and standard cine CMR sequences of the aortic root. Our study included 741 subjects (mean age 63.5 ± 8 years, 43.7% female) from the Hamburg City Health Study (HCHS). Subjects underwent CMR and TTE. Aortic root measurements were performed at the level of the aortic annulus (AoAn), sinus of Valsalva (SoV), and sinotubular junction (STJ) by standard cine CMR in left ventricular long axis and left ventricular outflow tract view. Measurements were performed applying the leading-edge to leading-edge (LL) convention and inner-edge to inner-edge (II) convention in TTE and the II convention in CMR. Inter correlation coefficients (ICCs) demonstrated high inter- and intraobserver reproducibility for CMR and TTE measurements of SoV and STJ (ICCs 0.9–0.98) and moderate reproducibility for AoAn (ICCs 0.68–0.91). CMR measurements of SoV and STJ showed strong agreement with TTE: while correlations were comparable (r = 0.75–0.85) bias was lower with TTE II (bias − 0.1 to − 0.74) versus TTE LL measurements (mean bias − 1.49 to − 2.58 mm). The agreement for AoAn was fair (r = 0.51–0.57) with variable bias (mean bias 0.39–3.9). Standard cine CMR and TTE derived aortic root measurements are reproducible and comparable with higher agreement for TTE II instead of LL measurements. These results support an interchangeable application of TTE and standard CMR for screening of aortic root diseases thereby possibly reducing redundant multimodality imaging.

Magnetic resonance angiography derived predictors of progressive dilatation and surgery of the aortic root in Marfan syndrome

Background

To identify magnetic resonance (MR) angiography derived predictors of progressive dilatation and surgery of the aortic root in Marfan syndrome.

Material and methods

We retrospectively included 111 patients (32.7±16.5 years, range: 7–75 years) with a total of 446 MR angiographies. Aortic diameter growth rates of the entire thoracic aorta and Z-scores were estimated from annual diameter measurements. Aortic root shape was subdivided into three different types: (T0) normal; (T1) localized dilatation; (T2) generalized aortic root dilatation. Aortic diameter, Z-score, age, and aortic root shape at baseline were tested as predictors of aortic root dilatation using a multivariate logistic regression model.

Results

The highest aortic growth rate was observed at the level of the sinuses of Valsalva. Higher aortic root diameters and Z-scores at baseline predicted an increased growth of the aortic root (p = 0.003 and p<0.001). Young age (<30 years) was a predictor for the increase of Z-scores when compared to patients ≥30 years (p = 0.019). 25/111 patients (22.5%) had a T0 aortic root shape, 59/111 patients (53.2%) had a T1 aortic root shape, and 27/111 patients (24.3%) had a T2 aortic root shape. Aortic root shape did not predict further aortic growth (p>0.05). However, significantly more patients undergoing surgery had a generalized aortic dilatation (19/28, 76.9%) than a localized aortic root dilatation (9/28, 32.1%) (p = 0.001).

Conclusion

Larger baseline aortic root diameter and Z-score as well as young age predict solely progressive aortic root dilatation in Marfan patients. MR angiography derived type of aortic root shape does not predict aortic growth, but patients with generalized aortic root dilatation are referred more frequently for aortic surgery.

Using three-dimensional visualization as an optimal tool to plan and validate an aortopexy in a congenital heart disease patient with severe tracheal stenosis

We present a patient with severe tracheal stenosis resulting from a compression by the innominate artery 6 months after an arterial switch operation in a dextro-transposition of the great arteries. Segmentation and three-dimensional (3D) visualization were derived from a contrast-enhanced dual-source computed tomography and post-processing was performed using a dedicated open-source platform (3D Slicer). Post-processing allowed a comprehensible visualization of the relationship of the innominate artery to the trachea when compared to standard computer tomography reformations. Finally, the surgical approach to move the innominate artery anteriorly in order to relieve the tracheal obstruction was emphasized based on the improved 3D visualization of the actual pathology. An effective aortopexy could be performed and the postoperative result was confirmed by a second 3D visualization. About 3 months of follow-up, the patient is completely asymptomatic. Three-dimensional visualization offers excellent opportunities for diagnosis, treatment planning and follow-up in patients with a vascular-related tracheal stenosis in the context of congenital heart disease.

Accuracy of preoperative CT staging of acute colonic diverticulitis using the classification of diverticular disease (CDD) - Is there a beneficial impact of water enema and visceral obesity?

PURPOSE

We evaluated the accuracy of preoperative CT in staging colonic diverticulitis (ACD) by using the classification of diverticular disease (CDD) and investigated the diagnostic impact of water enema (WE) and visceral obesity.

METHODS

In this retrospective study, the radiological and hospital information system was searched for patients who underwent CT for clinically suspected ACD prior to surgery between 2009 and 2019. From the initial population (n = 164), we included 155 patients (94.5 %) (85 women; mean age: 58 ± 13 years) matching the following inclusion criteria: i.) clinically suspected ACD, ii.) i.v. contrast-enhanced CT, iii.) surgery for ACD within 1 week after CT, iv.) histopathological report that proved ACD. The remaining 9 patients (5.5 %) were excluded because histopathological reports were lacking (n = 3) or CT was performed without intravenous contrast agent (n = 6). WE (+ butylscopolamine i.v.) was performed in 93 patients (group A, 60 %). 62 patients (group B, 40 %) had no WE. Visceral-to-subcutaneous fat ratio (V/S) was determined for each patient. Two radiologists blinded for final diagnosis independently staged ACD according to CDD and assessed prevalence and confidence ratings of ACD-related CT-findings: pericolonic fat stranding, covered- and free-perforation, local and generalized peritonitis, abscess. Interobserver-agreement of CT-findings were assessed and effects of WE and V/S ratio on the diagnostic accuracy of CT with surgical and histopathological findings as reference were determined by calculating a logistic regression model.

RESULTS

CT-staging showed high accuracy (94 %) and excellent interrater-correlation (ICC 0.96) for staging ACD. WE had no positive impact neither on diagnostic accuracy of staging, nor on confidence ratings of ACD-related CT-findings (all p > 0.5). Confidence ratings were significantly higher in examinations without WE for perforation, peritonitis as well as abscesses (all p < 0.5). Confidence ratings for the assessment of local peritonitis improved significantly with higher V/S (p = 0.049). The increase of V/S significantly correlated with the probability for correct CDD staging of ACD in CT (p = 0.023).

CONCLUSION

Increase of visceral obesity significantly improves accuracy of CT in preoperative staging acute colonic diverticulitis. However, independently of the degree of visceral obesity, water enema has no diagnostic benefit and may therefore be omitted. Overall, CT proves high accuracy in preoperative staging ACD using the classification of diverticular disease.

LEVEL OF EVIDENCE

Retrospective study, observational study.

Intraindividual comparison of 1.5 T and 3 T non-contrast MR angiography for monitoring of aortic root diameters in Marfan patients

BACKGROUND

Reproducible aortic diameter measurements are crucial for assessment of aortic growth and aneurysm formation in patients with Marfan syndrome. The objective of this study was to perform an intraindividual comparison of aortic measurements at 1.5 T and 3 T using non-contrast magnetic resonance angiography (MRA) in pre-surgical and post-surgical Marfan patients.

METHODS

Forty consecutive Marfan patients were retrospectively evaluated by ECG-gated 2D balanced steady-state free precession (bSSFP) MRA at 1.5 T and 3 T after 363 ± 58 days. 24 patients were before and 16 patients after aortic root surgery. Two readers independently measured aortic diameters at seven aortic levels and rated the image quality/image artifacts (1 = poor/severe, 4 = excellent/none). Contrast-to-noise ratio (CNR) and signal intensity slopes between aortic lumen and vessel walls were semiautomatically determined.

RESULTS

In pre-surgical Marfan patients, interobserver agreement of aortic root diameter measurements was significantly higher at 3 T compared to 1.5 T (p < 0.05). In post-surgical Marfan patients, image quality and artifacts were significantly worse at 3 T compared to 1.5 T (p < 0.05). CNR was higher at 3 T compared to 1.5 T at all aortic levels. Significantly steeper slopes of signal intensity curves were observed at 3 T at all aortic levels (p < 0.001).

CONCLUSIONS

In pre-surgical Marfan patients, non-contrast MRA provides higher reproducibility of aortic diameter measurements at 3 T compared to 1.5 T. In post-surgical Marfan patients, metallic implants result in significantly worse imaging artifacts and reduced image quality at 3 T compared to 1.5 T. Therefore, we propose to monitor the thoracic aorta with non-contrast MRA at 3 T in pre-surgical Marfan patients and at 1.5 T in post-surgical Marfan patients.

Sensitivity of High-Pitch Dual-Source Computed Tomography for the Detection of Anomalous Pulmonary Venous Connection in Infants

PURPOSE

 To evaluate the sensitivity, specificity, and interobserver reliability of high-pitch dual-source computed tomography angiography (CTA) in the detection of anomalous pulmonary venous connection (APVC) in infants with congenital heart defects and to assess the associated radiation exposure.

MATERIALS AND METHODS

 78 pulmonary veins in 17 consecutively enrolled patients with congenital heart defects (6 females; 11 males; median age: 6 days; range: 1-299 days) were retrospectively included in this study. All patients underwent high-pitch dual-source CTA of the chest at low tube voltages (70 kV). APVC was evaluated independently by two radiologists. Sensitivity, specificity, positive (PPV) and negative predictive values (NPV), and interobserver agreement were determined. For standard of reference, one additional observer reviewed CT scans, echocardiography reports, clinical reports as well as surgical reports. In cases of disagreement the additional observer made the final decision based on all available information.

RESULTS

 Detection of APVC with high-pitch dual-source CTA revealed a good sensitivity (91 %) and specificity (99 %), with PPV and NPV of 98 % and 97 %. Interobserver agreement was almost perfect (Kappa = 0.84). The median DLP was 3.8 mGy*cm (IQR 3.3-4.7 mGy*cm) and the median radiation dose was 0.33 mSv (IQR 0.26-0.39 mSv).

CONCLUSION

 High-pitch dual-source CTA in infants with congenital heart defects allows for accurate and reliable assessment of APVC at a low radiation dose.

KEY POINTS

  · High-pitch dual-source CTA enables detection of anomalous pulmonary vein connection with high sensitivity in infants.. · Interrater reliability in the detection of anomalous pulmonary vein connection with high-pitch dual-source CTA is almost perfect.. · Radiation dose of high-pitch dual-source CTA in the cardiac examination of infants is low..

CITATION FORMAT

· Well L, Weinrich JM, Meyer M et al. Sensitivity of High-Pitch Dual-Source Computed Tomography for the Detection of Anomalous Pulmonary Venous Connection in Infants. Fortschr Röntgenstr 2021; 193: 551 - 558.

Feasibility of extremely reduced-dose CT of the thoracic spine in human cadavers

BACKGROUND

According to the as low as reasonably achievable (ALARA) principle, radiation exposure in computed tomography (CT) should be minimized while maintaining adequate image quality. Dedicated CT protocols combined with iterative reconstruction (IR) can reduce radiation dose and/or improve image quality.

PURPOSE

To investigate the feasibility of extremely reduced-dose (RD) CT of the thoracic spine in human cadavers using a standard-dose (SD) and three different RDCT protocols reconstructed with filtered back projection (FBP) and IR.

MATERIAL AND METHODS

The thoracic spines of 11 cadavers were examined using different RDCT protocols with decreasing reference tube currents (RDCT-1: 50 mAs; RDCT-2: 30 mAs; RDCT-3: 10 mAs) at 140 kV. A clinical SDCT (70 mAs, 140 kV) served as reference. Raw data were reconstructed using FBP and two increasing levels of IR (IRL4 and IRL6). Images were evaluated for image quality, diagnostic acceptability, and visibility of anatomical structures according to a 5-point-scale.

RESULTS

Regardless of the reconstruction technique, image quality was rated as diagnostically acceptable for all cadavers in SDCT and RDCT-1. Image quality of reconstructions with FBP were generally rated lower. Application of IR improved image quality ratings in SDCT and RDCT. RDCT-2 with IR was the most reduced-dose CT protocol which enabled diagnostically acceptable image quality in all cadavers. Compared to SDCT, RDCT protocols resulted in significantly reduced effective radiation doses (SDCT: 4.1 ± 1.5 mSv; RDCT-1: 2.9 ± 1.1 mSv; 2:1.7 ± 0.6 mSv; 3:0.6 ± 0.1 mSv; P = 0.001).

CONCLUSION

Diagnostically acceptable RDCT of the thoracic spine with 1.7 mSv is feasible using IR.

Reliability of non-contrast magnetic resonance angiography-derived aortic diameters in Marfan patients: comparison of inner vs. outer vessel wall measurements

Aortic diameter measurements play a crucial role for the indication of aortic root surgery in Marfan patients. However, for magnetic resonance angiography (MRA)-derived measurements, there is no consensus on whether the aortic wall should be included or excluded in the aortic diameter. The purpose of this retrospective study was to compare the reliability of non-contrast bright blood MRA aortic inner-to-inner and outer-to-outer edge measurements in patients with Marfan syndrome. Forty Marfan patients underwent ECG-gated balanced steady-state free-precession MRA of the aorta at 1.5 T. Two readers independently performed inner and outer measurements at different aortic levels. They rated the image quality of the delineation of both inner and outer vessel wall edges on a four-point scale. MRA-derived diameters of the sinuses of Valsalva were compared with echocardiography-derived diameters. Aortic vessel wall delineation score was rated higher at all levels for inner than for outer vessel walls (p < 0.001). Inter- and intraobserver variances of aortic measurements were smaller for inner-to-inner measurements at the sinuses of Valsalva, sinotubular junction and ascending aorta (p < 0.03). There was a difference of 1.1 ± 2.3 mm for inner MRA measurements (p = 0.014) and 6.9 ± 3.1 mm for outer MRA measurements (p < 0.001) when compared to echocardiographic leading-edge measurements. Inner-to-inner vessel wall diameter measurements in non-contrast bright blood MRA provide more reliable diameters when compared to outer-to-outer vessel wall measurements of the aortic root. Therefore, we propose to rely on inner rather than outer aortic wall measurements in non-contrast-MRA when monitoring aortic diameters in patients with Marfan syndrome.

Comparison of different iterative CT reconstruction techniques and filtered back projection for assessment of the medial clavicular epiphysis in forensic age estimation

PURPOSE

To assess the impact of iterative reconstruction and filtered back projection (FBP) on image quality in computed tomography (CT)-based forensic age estimation of the medial clavicular epiphysis.

METHODS AND MATERIALS

CT of the clavicle was performed in 19 patients due to forensic reasons (70 mAs/140 kVp). Raw data were reconstructed with FBP and with an iterative algorithm at level 4 and 6. Clavicular ossification stage was determined by two radiologists in consensus, firstly on FBP reconstructed images and secondly after reviewing all reconstructions including iDose 4 and 6. In addition, the 3 reconstructions were compared regarding artefacts and delineation of the meta-/epiphyseal interface. Quantitative image noise was measured.

RESULTS

Quantitative noise was lower in iDose 6 reconstructed images than in FBP (P < 0.042), but not significantly lower between iDose 4 and FBP (P = 0.127). Side by side comparison revealed lesser qualitative image noise on both iDose reconstructed images than for FBP. The meta-/epiphyseal interface delineation was rated better on both iDose levels than with FBP. In 3 of 19 patients, the clavicular ossification stage was reclassified after iterative reconstructions had been additionally reviewed.

CONCLUSION

Using iterative CT reconstruction algorithms, a reduction of image noise and an enhancement of image quality regarding the meta-/epiphyseal clavicular interface can be achieved. The study highlights the importance of image standardization as variation of reconstruction technique has impact on forensic age estimation.

Feasibility of sub-milliSievert CT of the cervical spine: Initial results in fresh human cadavers

PURPOSE

To investigate the feasibility of sub-milliSievert CT of the cervical spine in fresh human cadavers using a standard-dose (SD) and four different reduced-dose (RD) protocols reconstructed with filtered back projection (FBP) and iterative reconstruction (IR).

METHODS

The cervical spine of 29 cadavers was examined using different RDCT protocols with decreasing reference tube currents (RDCT-1:70 mAs; RDCT-2:50 mAs; RDCT-3:30 mAs; RDCT-4:10 mAs) at 140 kV. A clinical SDCT (160 mAs, 120 kV) served as reference. Raw data were reconstructed using FBP and two increasing levels of IR (IRL4&6). Images of the upper (C1-4) and lower (C5-7) cervical spine were evaluated for image quality, diagnostic acceptability and visibility of anatomical structures according to a 5-point-scale.

RESULTS

Image quality of the upper cervical spine was diagnostically acceptable for all protocols using FBP and IR except for RDCT-4 with FBP. Image quality of the lower cervical spine was rated as non-diagnostic in RDCT-3 with FBP and RDCT-4 with FBP and IR. RDCT-3 with IR was the most reduced dose CT protocol allowing diagnostically acceptable image quality for both upper and lower cervical spine in all cadavers. RDCT protocols achieved significantly reduced effective radiation doses (SDCT: 1.5 ± 0.7 mSv; RDCT-1:1 ± 0.6 mSv; RDCT-2:0.7 ± 0.4 mSv; RDCT-3:0.4 ± 0.2 mSv; RDCT-4:0.2 ± 0.1 mSv; p < 0.001).

CONCLUSION

Diagnostically acceptable sub-milliSievert CT of the cervical spine is feasible with a low reference tube current at 140 kV using iterative reconstruction and could be suitable for isolated cervical trauma in cooperative patients.

Current and Emerging Imaging Techniques in Patients with Genetic Aortic Syndromes

Background Patients with genetic aortic syndromes such as Marfan or Loeys-Dietz syndrome have a decreased life expectancy due to the risk of aortic dissection and rupture. Imaging plays an important role in the acute setting but also in the initial diagnosis and image-based monitoring. In this article, we provide an overview of the most common genetic aortic syndromes and recommended imaging strategies. Furthermore, we highlight modern imaging methods allowing for the quantification of hemodynamic changes in aortic disease.

Method This is a narrative review article on genetic aortic syndromes and recommended imaging strategies, where we take into account expert opinions and standard-of-care practices from our own center.

Results and Conclusion Radiological imaging plays a key role in the initial diagnosis and surveillance of patients with genetic aortic syndromes. Radiologists contribute significantly to the multi-disciplinary setting of genetic aortic syndromes with knowledge of special features and recommended imaging methods. Accurate measurement of the aorta is crucial, particularly in terms of diameter-based surgical treatment algorithms. Modern imaging methods like 4D-flow MRI and pulse wave velocity have a potential to further improve individualized risk stratification in patients with genetic aortic syndromes.

Key points: 

Citation Format

Impact of Myocardial Fibrosis on Left Ventricular Function Evaluated by Feature-Tracking Myocardial Strain Cardiac Magnetic Resonance in Competitive Male Triathletes With Normal Ejection Fraction

BACKGROUND

To analyze the effect of myocardial fibrosis on left ventricular (LV) function evaluated by feature-tracking strain analysis by cine cardiac magnetic resonance (CMR) in competitive male triathletes with normal ejection fraction (EF).Methods and Results:78 asymptomatic male triathletes with >10 weekly training hours (43±11 years) and 28 male age-matched controls were studied by late gadolinium enhancement (LGE) and cine CMR. Global and segmental radial, longitudinal and circumferential strains were analyzed using feature-tracking cine CMR. Focal non-ischemic LGE was observed in 15 of 78 triathletes (19%, LGE+) with predominance in the basal inferolateral segments. LVEF was normal in LGE+ (62±6%) and LGE- triathletes (62±5%, P=0.958). In contrast, global radial strain was lower in LGE+ triathletes at 40±7% compared with LGE- triathletes (45±7%, P<0.05). Reduced segmental radial strain occurred either in LGE+ segments or in directly adjacent segments. Strain analysis revealed regional differences in controls, with the highest radial and longitudinal strain in the inferolateral segments, which were typically affected by fibrosis in LGE+ triathletes.

CONCLUSIONS

Reduced global and regional radial strain suggests a negative effect of myocardial fibrosis on LV function in LGE+ triathletes with normal EF. The observed regional differences in controls with the highest radial and longitudinal strain in the inferolateral segments may explain the typical occurrence of fibrosis in this myocardial region in triathletes.

Assessment of Congenital Vascular and Organ Anomalies in Subjects With Thalidomide Embryopathy Using Non-Contrast Magnetic Resonance Angiography

BACKGROUND

To determine the type and frequency of vascular and organ malformations in adults with thalidomide embryopathy (TE) using non-contrast magnetic resonance angiography (MRA) and to assess the effect of the observed malformations on renal function. Methods and Results: The institutional ethics committee approved this prospective study and written informed consent was given by all 78 subjects (50 females) with TE (mean age: 55±1.1 years), who were examined by non-contrast MRA at 3T. ECG-triggered balanced turbo field echo images of the chest, abdomen and pelvis were obtained in coronal and sagittal orientations. Two observers assessed the frequency of vascular and organ malformations. Serum creatinine and estimated glomerular filtration rate (eGFR) were obtained to assess renal function. In 58 subjects, 99 vascular anomalies were observed, including 68 arterial (69%) and 31 venous anomalies (31%); 15 patients had 16 abdominal organ malformations including 12 kidney anomalies and 4 cases of gallbladder agenesis. Most vascular anomalies affected the renal vessels (n=66, 67%) or supraaortic arteries (n=28, 28%). Serum creatinine and eGFR revealed normal renal function in all subjects.

CONCLUSIONS

Vascular and organ anomalies occurred in a high number of subjects with TE without evidence of renal dysfunction. Information about the presence of malformations may be important for future surgical interventions in subjects with TE.

MDCT in suspected lumbar spine fracture: comparison of standard and reduced dose settings using iterative reconstruction

AIM

To compare standard (SD-) and reduced-dose computed tomography (RD-CT) in combination with iterative reconstruction (IR) in emergency patients with suspected lumbar spine fracture.

MATERIAL AND METHODS

Forty emergency patients with suspected lumbar spinal disorder who underwent RD-CT and 40 body mass index-matched patients undergoing SD-CT were enrolled in this retrospective study. Raw data for RD-CT were reconstructed using two increasing IR levels (IRL) 4 and 6, while SD-CT was reconstructed with IRL3. Two radiologists assessed image quality, image noise, and reader confidence in interpreting findings of spinal fractures in a blinded manner.

RESULTS

Effective radiation dose was reduced by 50% using RD-CT. Overall subjective image quality (SIQ) was high for both protocols and slightly superior in the RD-CT protocol for both IRL compared to SD-CT. The detection rate of spinal disorders was high for both protocols with a high interobserver agreement.

CONCLUSION

RD-CT with higher levels of IR results in substantial dose reduction of 50% in lumbar spine CT while maintaining an excellent subjective image quality resulting in a high diagnostic confidence.

Gadolinium-based relative contrast enhancement in primary sclerosing cholangitis: additional benefit for clinicians?

AIM

To evaluate the benefit of extracellular gadolinium-based contrast agent (GBCA) enhanced magnetic resonance imaging (MRI) in addition to conventional non-enhanced T2-weighted imaging (WI) for quantification of inflammatory or fibrotic alterations in the liver parenchyma of patients with primary sclerosing cholangitis (PSC).

MATERIAL AND METHODS

MRI (3 T) examinations were reviewed retrospectively by two radiologists in 27 PSC patients (age 42.9±15.6 years), and 19 controls. Regions of interest (ROIs) were drawn onto T2 hyperintense and T2 isointense areas and copied to section position matched non-enhanced and delayed-phase contrast-enhanced T1WI. Signal intensities (SI) obtained from ROIs of the multiphase T1WI were used to calculate relative liver enhancement (RLE). The interobserver agreement of RLE and quantified T2 signal was calculated using Bland-Altman analysis. RLE assessed for both T2 hyperintense (RLE_hyper) and T2 isointense (RLE_iso) areas were compared in patients and controls (RLE_healthy).

RESULTS

The interobserver agreement of RLE in affected hyperintense areas (bias -0.77, limits of agreement -51.7 to 50.1) was superior to the quantification of T2 signal only in these areas (bias -3.35, limits of agreement -162.4 to 155.7). The RLE_hyper (86.2±9.7%) was higher than the RLE_iso (59.8±6.2%, p=0.03) and the RLE_healthy (53.2±2.7%, p=0.002). The mean RLE_iso was not significantly different from the RLE_healthy (p=0.3).

CONCLUSION

The extracellular gadolinium-based RLE of T2 hyperintense areas could be a useful add-on for routine follow up MRI in the detection of early inflammatory changes, possibly preceding formation of fibrotic scarring in PSC patients, if validated in larger cohorts.

Case report of a novel nonsyndromic unilateral syndactyly of the hand

Syndactyly is a cutaneous and/or bony digital malformation with possible webbing of adjacent fingers or toes and uni- or bilateral occurrence. We report an 84-year old woman with a novel non-syndromic congenital malformation of her left hand. Clinical examination showed that she only had four digits. Radiograph of the hand revealed synostosis of the second and third proximal phalanx, resulting in a triangular shaped bone with relatively normal articulations at both ends. The phalangeal base of the fused finger tapers distally and is broader than the middle phalangeal bases of the ring and little finger. This malformation does not fit in any of the known types of syndromic or non-syndromic syndactylies. Our case report highlights that radiological imaging is crucial for identification of bony syndactyly and correct classification of a given syndactyly. Knowledge of the different types of syndactylies is important because certain malformations may occur as a defining part of a syndromic disease.

Transient Severe Respiratory Motion Artifacts After Application of Gadoxetate Disodium: What We Currently Know

BACKGROUND

Gadoxetate disodium is an intracellular contrast agent for magnetic resonance imaging (MRI) of the liver. Recent publications revealed that injection of gadoxetate disodium can lead to imaging artifacts due to transient severe motion (TSM) in the arterial phase of contrast-enhanced liver MRI. In this review we present and discuss published frequencies of TSM, contrast injection and image acquisition protocols, potential risk factors, and proposed strategies to avoid or minimize the effects of TSM.

METHOD

Two reviewers independently searched the PubMed search engine for "transient severe motion artifact" and related terms. Reference lists of retrieved articles were also searched. The two reviewers selected in consensus nine studies that reported both frequencies of TSM and potential risk factors. Study data were extracted by both reviewers, and disagreement was resolved by consensus.

RESULTS AND CONCLUSION

TSM is caused by impaired breath-hold ability after gadoxetate disodium injection and occurs in 5 - 22 % of patients. The dose of applied contrast agent, repeated exposure to gadoxetate disodium, high BMI and pulmonary disease have been described as potential risk factors for TSM. However, there are only few concordant results on this topic and the pathophysiology of TSM has not been identified. Proposed strategies for the prevention of TSM are slow injection rates and low doses of diluted gadoxetate disodium. Accelerated and free-breathing MRI sequence protocols and breath-hold training may minimize the effects of TSM. Further prospective studies are needed to confirm these strategies and to identify the underlying mechanism of TSM.

KEY POINTS

· TSM occurs in 5 - 22 % of patients after gadoxetate disodium injection.. · Potential risk factors of TSM are dose, repeated exposure, BMI, pulmonary disease.. · The underlying mechanism for TSM has not been identified.. · Slow injection rates and diluted gadoxetate disodium may prevent TSM.. · Accelerated image acquisition or free-breathing sequences may mitigate the effects of TSM..

CITATION FORMAT

· Well L, Weinrich JM, Adam G et al. Transient Severe Respiratory Motion Artifacts After Application of Gadoxetate Disodium: What We Currently Know. Fortschr Röntgenstr 2018; 190: 20 - 30.