Patterns of Signal Intensity in CISS MRI of the Inner Ear and Eye.

BACKGROUND: Constructive interference in steady state (CISS) is a gradient echo magnetic resonance imaging (MRI) pulse sequence that provides excellent contrast between cerebrospinal fluid and adjacent structures but is prone to banding artifacts due to magnetic field inhomogeneities. We aimed to characterize artifacts in the inner ear and eye. METHODS: In 30 patients (60 ears/eyes) undergoing CISS sequence MRI, nine low-signal intensity regions were identified in the inner ear and compared to temporal bone histopathology. The number and angle of bands across the eye were examined. RESULTS: In the cochlea, all ears had regions of low signal corresponding to anatomy (modiolus (all), spiral lamina (n = 59, 98.3%), and interscalar septa (n = 50, 83.3%)). In the labyrinth, the lateral semicircular canal crista (n = 42, 70%) and utricular macula (n = 47, 78.3%) were seen. Areas of low signal in the vestibule seen in all ears may represent the walls of the membranous utricle. Zero to three banding artifacts were seen in both eyes (right: 96.7%, mean 1.5; left: 93.3%, mean 1.3). CONCLUSION: Low signal regions in the inner ear on CISS sequences are common and have consistent patterns; most in the inner ear represent anatomy, appearing blurred due to partial volume averaging. Banding artifacts in the eye are more variable.

Dual-Energy Computed Tomography-Based Quantitative Bone Marrow Imaging in Non-Hematooncological Subjects: Associations with Age, Gender and Other Variables.

Background: Our aim is to assess the utility and associations of quantitative bone marrow attenuation (BMA) values measured on clinical dual-energy computed tomography (DECT) exams in non-hematooncologic subjects with skeletal regions, patient age, gender, and other clinical variables. Methods: Our local ethics committee approved this retrospective image data analysis. Between July 2019 and July 2021, 332 eligible patients (mean age, 64 ± 18 years; female, 135) were identified. Inclusion criteria were the availability of a standardized abdominopelvic DECT data set acquired on the same scanner with identical protocol. Eleven regions-of-interest were placed in the T11-L5 vertebral bodies, dorsal iliac crests, and femur necks. Patient age, gender, weight, clinical, habitual variables, inflammation markers, and anemia were documented in all cases. Results: Multi-regression analyses (all, p < 0.05) identified age as the strongest predictor of lumbar BMA (standardized coefficient: ß = −0.74), followed by CRP (ß = 0.11), LDH (ß = 0.11), and gender (ß = −0.10). In the lower thoracic spine, age was the strongest predictor (ß = −0.58) of BMA, followed by gender (ß = −0.09) and LDH (ß = 0.12). In femoral bones, age was negatively predictive of BMA (ß = −0.12), whereas LDH and anemia were positively predictive (ß = 0.16 both). Heart insufficiency significantly decreased (ß = 0.12, p = 0.034) a BMA value gradient from higher to lower HU values along the vertebrae T11 and L5, whereas age significantly increased this gradient (ß = −0.2, p ≤ 0.001). Conclusions: DECT-based BMA measurements can be obtained from clinical CT exams. BMA values are negatively associated with patient age and influenced by gender, anemia, and inflammatory markers.

Is a single portal venous phase in contrast-enhanced CT sufficient to detect metastases or recurrence in clear cell renal cell carcinoma? - a single-center retrospective study.

BACKGROUND: This study aims at describing the imaging features of the metastatic presentation of clear cell renal cell carcinoma (ccRCC) in arterial (AP) and portal venous phase (PVP) of contrast-enhanced-computed-tomography (CECT) during clinical follow-up (FU) and to evaluate the necessity of a dual phase approach for metastasis detection. METHODS: We identified a total of 584 patients that were diagnosed with ccRCC between January 2016 and April 2020. Inclusion criteria were histologically proven ccRCC with metastatic spread, proven by histology or interim follow-up of at least 2 years and follow-up CT examination with AP and PVP CECT including thorax/abdomen and pelvis. Exclusion criteria were defined by missing or incomplete CT-scans or lack of sufficient follow-up. CT studies of 43 patients with histologically proven ccRCCs were analyzed in retrospect. AP and PVP images were analyzed by two radiologists for metastases, two additional independent radiologists analyzed PVP images only. A 5-point Likert scale was used to evaluate the likelihood off the presence of metastasis. Imaging patterns of the metastases were analyzed visually. RESULTS: 43 patients (16 female; mean age: 67±10 years) with recurrent ccRCC and metastatic disease were included. Three imaging patterns were observed (solid, heterogeneous or cystic metastases), which rarely exhibited calcifications (2%). All metastases showed hyperenhancement in AP and PVP. Inter-reader agreement was substantial (Fleiss' κ 0.6-0.8, p<0.001). No significant differences in sensitivity or specificity between readers (AP and PVP images vs. PVP images only) were present (79.4-85.2%, 97.1-99.6%, p ≥ 0.05). The area under the receiver-operating-characteristic (ROC) curve was between 0.901and 0.922 for all four radiologists. CONCLUSIONS: Similar rates for detection, sensitivity and specificity of metastasis and local recurrence in ccRCC were observed irrespective of using a dual-phase protocol with AP and PVP or a single PVP protocol only. Thus, a single-phase examination of PVP can be sufficient for experienced radiologists to detect metastatic disease in the follow-up of ccRCC patients.

Correlation between liver volume and liver weight in a cohort with chronic liver disease: a semiautomated CT-volumetry study.

BACKGROUND: To estimate the optimal density coefficient for conversion of liver volume into liver weight in patients with chronic liver disease based on semiautomated CT-liver volumetry data and the histologic Ishak score of explanted liver. METHODS: A total of 114 patients (39 female; age, 46±20 years) with chronic liver diseases who underwent liver transplantation between January 2010 and September 2020 were identified over a patient chart search at our institution and subsequently analyzed in retrospect. All patients had contrast-enhanced CT-examinations (mean, 24 days) to liver transplantation. Liver volume was calculated by a semiautomated software and results compared with the liver weight registered by the pathologist. Each explanted liver was histologically scored into six classes according to the Ishak classification where the categories were subgrouped based on recommendation of the pathologists into the following categories 0-3, 4-5 and 6. RESULTS: Mean liver volume was 1,870±1,195, 1,162±679 and 1,278±510 mL for the categories 0-3, 4-5 and 6, respectively. Mean liver weight was 1,624±999, 1,082±669 and 1,346±559 g for the categories 0-3, 4-5 and 6, respectively. A coefficient of 0.92±0.22, 0.98±0.28 and 1.06±0.20 g/mL was found at best for conversion of liver volume into liver weight in these subgroups. Differences between Ishak-subgroups proved significant (0.002). In 4 patients with cystic liver disease, density coefficients varied significantly and were found generally lower compared to the other liver disorders. CONCLUSIONS: Our results yielded significant differences between the density coefficients calculated along with the Ishak score and also for the subgroup with cystic liver disease.

Three-Dimensional High-Resolution Temporal Bone Histopathology Identifies Areas of Vascular Vulnerability in the Inner Ear.

OBJECTIVES: Hypothesized causes of vestibular neuritis/labyrinthitis include neuroinflammatory or vascular disorders, yet vascular disorders of the inner ear are poorly understood. Guided by known microvascular diseases of the retina, we developed 2 hypotheses: (1) there exist vascular vulnerabilities of artery channels in cases of hypothetical nerve swelling for the superior, inferior, and vestibulocochlear artery and (2) there are arteriovenous crossings that could compromise vascular flow in disease states. METHODS: Two fully mounted and stained temporal bones were used to render three-dimensional reconstructions of the labyrinth blood supply. Using these maps, areas of potential vascular compression were quantified in 50 human temporal bones. RESULTS: Although inner ear arteries and veins mostly travel within their own bony channels, they may be exposed (1) at the entrance into the otic capsule, and (2) where the superior vestibular vein crosses the inferior vestibular artery. At the entry into the otic capsule, the ratio of the soft tissue to total space for the superior vestibular artery was significantly greater than the inferior vestibular artery/cochleovestibular artery (median 44, interquartile range 34-55 vs. 14 [9-17], p < 0.0001). CONCLUSIONS: Three-dimensional reconstruction of human temporal bone histopathology can guide vascular studies of the human inner ear. Studies of retinal microvascular disease helped identify areas of vascular vulnerability in cases of hypothetical nerve swelling at the entrance into the otic capsule and at an arteriovenous crossing near the saccular macula. These data may help explain patterns of clinical findings in peripheral vestibular lesions.

Diagnostic benefit of multiparametric MRI over contrast-enhanced CT in patients with bladder cancer: A single-center 1-year experience.

PURPOSE: To assess the clinical applicability of local tumor staging in urinary bladder cancer (BC) with preoperative multiparametric MRI (mpMRI) using the five-point Vesical Imaging-Reporting and Data System (VI-RADS) scoring system and to compare it to dual-phase contrast-enhanced computed tomography (CECT). METHODS: 33 patients with primary untreated bladder cancer underwent CECT followed by preoperative multiparametric 3.0 T MRI between July 2019 and August 2020 and were enrolled in this retrospective study. Two radiologists initially performed staging on the CECT image data sets and - blinded to CT results - on subsequent mpMRI. BCs were staged according to the VI-RADS scoring system. Postoperative pathology was correlated to the VI-RADS score and the CECT results. The performance of VI-RADS in determining detrusor muscle invasion was analyzed using a receiver operating characteristic curve. Based on the histopathology, sensitivity, specificity and accuracy for muscle invasiveness between both image modalities were compared using the Chi square test. RESULTS: A total of 33 patients (29 male, median age 70 years, IQR: 59-81 years) were included. 10 tumors were categorized as non-muscle invasive (30%) and 23 as muscle invasive BC (70%) in final histology. Tumor stages were correctly assigned as being either muscle invasive or non-muscle invasive on both CECT and mpMRI with regard to both early and late stages of BC (Ta-Tis and T3a-T4b). T-stages bordering the histopathologic limits of muscle invasiveness (T1-T2a-b) resulted in overestimation of muscle invasion in 43% of cases (VI-RADS 3-4) for the mpMRI image data sets and in an underestimation of muscle invasion in up to 55.5% of cases analysing the CECT data. Sensitivity and specificity for the determination of muscle invasion in CECT and mpMRI were 80%/80% and 74%/61% for Radiologist#1 and 70%/90% and 83%/70% for Radiologist#2, respectively. CONCLUSIONS: There are advantages and disadvantages of both CECT and mpMRI when used in the clinical assessment of BC muscular tumor invasion. In borderline cases, only the combination of cross-sectional imaging and histopathological staging may help in making the optimal treatment decisions.

Fully automated whole-liver volume quantification on CT-image data: Comparison with manual volumetry using enhanced and unenhanced images as well as two different radiation dose levels and two reconstruction kernels.

OBJECTIVES: To evaluate the accuracy of fully automated liver volume quantification vs. manual quantification using unenhanced as well as enhanced CT-image data as well as two different radiation dose levels and also two image reconstruction kernels. MATERIAL AND METHODS: The local ethics board gave its approval for retrospective data analysis. Automated liver volume quantification in 300 consecutive livers in 164 male and 103 female oncologic patients (64±12y) performed at our institution (between January 2020 and May 2020) using two different dual-energy helicals: portal-venous phase enhanced, ref. tube current 300mAs (CARE Dose4D) for tube A (100 kV) and ref. 232mAs tube current for tube B (Sn140kV), slice collimation 0.6mm, reconstruction kernel I30f/1, recon. thickness of 0.6mm and 5mm, 80-100 mL iodine contrast agent 350 mg/mL, (flow 2mL/s) and unenhanced ref. tube current 100mAs (CARE Dose4D) for tube A (100 kV) and ref. 77mAs tube current for tube B (Sn140kV), slice collimation 0.6mm (kernel Q40f) were analyzed. The post-processing tool (syngo.CT Liver Analysis) is already FDA-approved. Two resident radiologists with no and 1-year CT-experience performed both the automated measurements independently from each other. Results were compared with those of manual liver volume quantification using the same software which was supervised by a senior radiologist with 30-year CT-experience (ground truth). RESULTS: In total, a correlation of 98% was obtained for liver volumetry based on enhanced and unenhanced data sets compared to the manual liver quantification. Radiologist #1 and #2 achieved an inter-reader agreement of 99.8% for manual liver segmentation (p<0.0001). Automated liver volumetry resulted in an overestimation (>5% deviation) of 3.7% for unenhanced CT-image data and 4.0% for contrast-enhanced CT-images. Underestimation (<5%) of liver volume was 2.0% for unenhanced CT-image data and 1.3% for enhanced images after automated liver volumetry. Number and distribution of erroneous volume measurements using either thin or thick slice reconstructions was exactly the same, both for the enhanced as well for the unenhanced image data sets (p> 0.05). CONCLUSION: Results of fully automated liver volume quantification are accurate and comparable with those of manual liver volume quantification and the technique seems to be confident even if unenhanced lower-dose CT image data is used.