Vanessa Berger-Kulemann

Gadoxetic acid-enhanced 3.0 T MR imaging versus multidetector-row CT in the detection of colorectal metastases in fatty liver using intraoperative ultrasound and histopathology as a standard of reference.

OBJECTIVE To compare the diagnostic value of gadoxetic acid-enhanced MRI at 3.0 T with 64-row MDCT in the detection of colorectal liver metastases in diffuse fatty infiltration of the liver after neoadjuvant chemotherapy. METHODS Twenty-three patients with colorectal liver metastases and at moderate to severe steatosis (25-90%) underwent prospectively preoperative tri-phasic MDCT (Somatom Sensation 64, Siemens) and gadoxetic acid-enhanced MRI (3-T Magnetom Trio, Siemens). All patients underwent surgical resection of liver metastases. Intraoperative ultrasound (IOUS) was carried out, which served as the standard of reference, together with histopathology. RESULTS Overall, 68 metastases (range, 0.4-6 cm; 31/68 metastases [46%] ≤ 1 cm) were found at histology. MDCT detected 49/68 lesions (72%), and MRI 66/68 (97%, p < 0.001). For lesions ≤ 1 cm, MDCT detected only 13/31 (41.9%) and MRI 29/31 (93%, p < 0.001). Eight false-positive lesions were detected by MDCT, seven small lesions by MRI. There was no statistically significant difference between the two modalities in the detection of lesions > 1 cm (p = 0.250). IOUS detected all metastases and revealed two false-positive diagnoses. CONCLUSION Gadoxetic acid-enhanced 3.0 T MRI is superior to 64-row MDCT in detecting colorectal liver metastases ≤ 1 cm during preoperative staging in patients with liver steatosis. A combination of MRI and IOUS may further improve the outcome of surgical treatment.

Texture-based classification of focal liver lesions on MRI at 3.0 Tesla: a feasibility study in cysts and hemangiomas.

To determine the feasibility of texture analysis for the classification of liver cysts and hemangiomas, on nonenhanced, zero‐fill interpolated T1‐ and T2‐weighted MR images.

Potential of magnetic resonance for imaging the fetal heart.

Significant congenital heart disease (sCHD) affects 3.6 per 1000 births, and is often associated with extracardiac and chromosomal anomalies. Although early mortality has been substantially reduced and the rate of long-term survival has improved, sCHD is, after preterm birth, the second most frequent cause of neonatal infant death. The prenatal detection of cardiac and vascular abnormalities enables optimal parental counselling and perinatal management. Echocardiography (ECG) is the first-line examination and gold standard by which cardiac malformations are defined. However, adequate examination by an experienced healthcare provider with modern technical imaging equipment is required. In addition, maternal factors and the gestational age may lower the image quality. Fetal magnetic resonance imaging (MRI) has been implemented over the last several years and is already used in the clinical routine as a second-line approach to assess fetal abnormalities. MRI of the fetal heart is still not routinely performed. Nevertheless, fetal cardiac MRI has the potential to complement ultrasound in detecting cardiovascular malformations and extracardiac lesions. The present work reviews the potential of MRI to delineate the anatomy and pathologies of the fetal heart. This work also deals with the limitations and continuing developments designed to overcome the current problems in cardiac imaging, including fast fetal heart rates, the lack of ECG-gating, and the presence of fetal movements.

MR Spectroscopy of the Fetal Brain: Is It Possible without Sedation?

BACKGROUND AND PURPOSE: The quality of spectroscopic studies may be limited because of unrestricted fetal movement. Sedation is recommended to avoid motion artefacts. However, sedation involves side effects. The aim of this study was to assess the feasibility and quality of brain 1H-MR spectroscopy in unsedated fetuses and to evaluate whether quality is dependent on the type of spectra, fetal presentation, GA, and/or fetal pathology. MATERIALS AND METHODS: Seventy-five single-voxel spectroscopic studies of the fetal brain, performed at gestational weeks 19–38 at 1.5T, were evaluated retrospectively. A PRESS (TE = 144 or 35 ms) was used. Fetal presentation, GA, and kind of pathology were recorded. The quality of the spectra was assessed by reviewing the spectral appearance (line width, signal-to-noise) of the creatine resonance obtained relative to concentrations (ratios-to-creatine) of choline, myo-inositol, and NAA. RESULTS: Of 75 studies, 50 (66.6%) were rated as readable: short TE = 17/50 (34%), long TE = 33/50 (66%), cephalic presentation in 36/50 (72%) studies, breech in 10/50 (20%) studies, and “other” presentation in 4/50 (8%) studies (mean GA, 31.0 weeks). Twenty-eight of 50 fetuses (56%) showed normal development (short TE = 12/28, long TE = 16/28), and 22/50 (44%) showed pathology. Of the 75 studies, 25 (33.3%) were not readable: short TE = 14/25 (56%), long TE = 11/25 (44%), cephalic presentation in 20/25 (80%) studies, breech in 4/25 (16%) studies, and other presentation in 1 study (4%) (mean GA, 30.1 week). Thirteen of 25 fetuses (52%) showed normal development; 12/25 (48%) showed pathology. Statistical analysis revealed no impact of the different parameters on the quality of spectra. CONCLUSIONS: Single-voxel spectroscopy can be performed in approximately two-thirds of unsedated fetuses, regardless of the type of spectra, fetal presentation, GA, and pathology.

Fetal magnetic resonance imaging of lymphangiomas.

Abstract Objectives: To evaluate the fetal magnetic resonance imaging findings of lymphangiomas. Methods: The magnetic resonance scans of eight fetuses with lymphangiomas were evaluated. Magnetic resonance evaluation included: number; size; signal intensities of the lesions; thickness of the septae; configuration of the margins; presence of blood breakdown products; change in size or signal intensity (in four patients with multiple examinations); exact expansion of the lesions to the adjacent anatomical structures; and concomitant pathological findings. Results were compared with postpartum clinical assessment and imaging in seven patients and with autopsy in one patient. Results: Two retroperitoneal, three thoracic, and three cervical lymphangiomas (diameters between 3.3 and 15.6 cm) were included. All lesions consisted of macrocysts, and additional microcystic parts were found in three lymphangiomas. Blood breakdown products were found in one lesion. Agreement with postpartum imaging was excellent. One patient received intrauterine drainage for chylothorax, and one pregnancy was terminated. Conclusions: Fetal lymphangiomas display the same magnetic resonance imaging features as postnatal lymphangiomas. Intrauterine magnetic resonance characterization of lymphangiomas provides the exact delineation, detection of associated and/or concomitant pathologies, and differential diagnosis among other cystic pathologies. Patient management may be altered with respect to the type and/or time of treatment, and with regard to the continuation or termination of pregnancy.

Hepatic steatosis assessment with 1H-spectroscopy and chemical shift imaging at 3.0 T before hepatic surgery: Reliable enough for making clinical decisions?

PURPOSE To compare the accuracy of liver fat quantification using chemical shift imaging (CSI) and H1 MR-spectroscopy (MRS) at 3.0 T in patients undergoing liver resection. METHODS Totally 35 patients were included in this prospective IRB approved study. The histopathologically assessed liver fat was compared to the hepatic fat fractions calculated with CSI (with and without spleen correction) and MRS. Spearmans rank correlation and Fisher z-test were used for correlation analysis. Sensitivity and specificity regarding the detection of marked steatosis were calculated for the different modalities and compared using the McNemar test. RESULTS MRS (r=.85) and CSI with spleen correction (r=.85) showed a significantly better correlation (p=.03) with histology compared to CSI without spleen correction (r=.67). Sensitivity and specificity for the detection of marked steatosis was 100% (12/12) and 87% (20/23) for MRS and 92% (11/12) and 83% (19/23) for CSI with spleen correction (p>.12). CONCLUSION For the assessment of hepatic steatosis both CSI with spleen correction and MRS at 3.0 T, show a good correlation with histology. CSI without spleen correction should not be used. Sensitivity and specificity for the detection of marked steatosis are high with both modalities. However, results that are scattered around the cut-off values are not reliable enough for clinical decisions.

Risk of inferior vena cava compression syndrome during fetal MRI in the supine position – a retrospective analysis

Abstract Objectives: Inferior vena cava compression syndrome (VCCS) is a serious complication of supine fetal magnetic resonance imaging (MRI) examinations, particularly during late gestation. This morphologic study correlated the occurrence of VCCS with the grade of inferior vena cava (IVC) compression. Materials and methods: There were 56 fetal MRI in the supine position [median gestational weeks (GW) 27+4] and 16 fetal MRI in the lateral position (median GW 30+6) retrospectively analyzed. The grade of maternal IVC compression was determined by the maximal anterior-posterior diameter (DAP) at the level of L4/L5. Fetal head position and right-sided uterus volume were analyzed. Clinical VCCS-related symptoms during fetal MRI were assessed. Results: A noncompressed IVC was present in 1.8% (n=1) and a DAP of 5 to <10 mm in 33.3% (n=19) and 1 to <5 mm in 64.9% (n=36). The DAP was independent of fetal head position (P=0.99) and showed no significant correlation with gestational age (r=0.33). IVC compression increased with right-sided uterus volume (r=–0.328; P=0.014). There was a significant difference in DAP in the lateral position compared with the supine position (P<0.001). Clinical assessment revealed no symptoms of VCCS in any woman. Conclusions: The presented data support the concept of physiologic compensation for significantly reduced venous backflow in the supine position during the second and third trimesters of pregnancy.

Quantification of the subcutaneous fat layer with MRI in fetuses of healthy mothers with no underlying metabolic disease vs. fetuses of diabetic and obese mothers.

Abstract Objective: To assess the age-dependent fetal subcutaneous fat layer (SCFL) of non-diabetic, normal-weight mothers and fetuses of mothers with gestational diabetes (GDM) and normal body weight or obesity. Methods: In a prospective study, we evaluated 115 MRI examinations of fetuses with no history of (maternal) metabolic disease [gestational week (GW) 29 to 39/40] and 50 examinations of mothers with GDM and normal body weight or obesity. The SCFL was measured at predetermined anatomical landmarks. Measurements were correlated with the maternal body mass index (BMI) and glycated hemoglobin A1c (HbA1c)-values in diabetic mothers. Results: In fetuses of non-diabetic, normal-weight mothers, measurements showed high consistency within the respective GW and ranged from 2 mm at GW 29 at all measured points, up to 4.5 mm at the trunk and 6.0 mm at the extremities at GW 39/40. In 47/50 fetuses of mothers with GDM, the SCFL was within the range of fetuses of mothers with no metabolic disease. In three patients with GDM and BMI<30, the SCFL-thickness was decreased. No fetuses showed an increased SCFL-thickness. Conclusion: The SCFL of normally developed fetuses is easily detectable from GW 29 on T1-weighted images (T1-W), and increases with gestational age. The presented data provide physiological benchmarks to evaluate developmental status and may help in the prenatal diagnosis of abnormal growth and macrosomia. In pregnant women with well-controlled GDM, an increase of the SCFL is not expected.

Needle image plates compared to conventional CR in chest radiography: is dose reduction possible?

PURPOSE To compare image quality of standard-dose computed radiography and dose reduced needle-technology CR for supine CXR in a clinical setting. MATERIALS AND METHODS We prospectively evaluated 128 radiographs of 32 immunocompromised patients. For each patient four clinical CXR were performed within one week, two with powder image plates (PIP; Fuji ST-V) and two with needle image plates (NIP; Agfa DXS) at standard and half dose, respectively. One experienced radiologist and two residents blinded to dose level and kind of imaging system rated different anatomical structures, image noise, tubes/lines and abnormalities on a image quality scale from 1 to 10 (1=poor, 10=excellent). The rating scores were tested for statistical differences using analysis of variance with repeated measures. RESULTS A statistical difference (p<0.05) was found for the two systems as well as for the two dose levels. Overall rating scores were 6.5 for PIP with full dose, 6.2 for PIP with half dose, 7.6 for NIP with full dose and 7.4 for NIP with half dose. There was a significant difference in favour of the NIP system at the same dose level. Also the NIP images obtained at half dose were ranked significantly better compared to the PIP images at standard dose. The differences in ranking of anatomical structures and abnormalities were more pronounced in low absorption areas (pulmonary vessels, parenchyma) than in high absorption areas (mediastinum, spine). CONCLUSION For supine chest radiograms the NIP technology allows for a dose reduction of 50% while providing higher image quality.

Magnetic Field Interactions of Copper-Containing Intrauterine Devices in 3.0-Tesla Magnetic Resonance Imaging: In Vivo Study

Objective An ex vivo study found a copper-containing intrauterine device (IUD) to be safe for women undergoing an MRI examination at a 3.0-T field. No significant artifacts caused by the metallic implant were detected. However, there are still no in vivo data about these concerns. The aim of this study was to evaluate 3.0-T magnetic field interactions of copper-containing IUDs in vivo. Materials and Methods Magnetic field interactions and potential adverse events were evaluated in 33 women using a questionnaire-based telephone survey. Two experienced radiologists performed artifact evaluation on MR images of the pelvis. Results Eighteen patients were eligible for the survey. One patient reported a dislocation of the IUD after the MR examination. All other patients had no signs of field interactions. No IUD-related artifacts were found. Conclusion MRI at 3.0-T is possible for women with copper-containing IUDs. However, consulting a gynecologist to check the correct position of the IUD and exclude complications after an MR examination is highly recommended. High-quality clinical imaging of the female pelvis can be performed without a loss in image quality.