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Journal of Computer Assisted Tomography - Current Issue

Journal of Computer Assisted Tomography - Current Issue
  1. Patterns of Coronary Calcification and Their Impact on the Diagnostic Accuracy of Computed Tomography Coronary Angiography
    imageObjective Despite coronary calcifications being a major factor affecting the diagnostic accuracy of coronary computed tomography angiography (CTA), there is a lack of established criteria for categorizing calcifications. We aimed to evaluate patterns of coronary calcification based on quantitative radiodensity and size parameters to provide coronary calcium categories and assess their impact on the accuracy of coronary CTA. Methods and Results We analyzed length, maximum thickness, volume, mean density, and maximum density of coronary calcium and divided each of these parameters into tertiles. Subsequently, we summarized the tertiles for each individual calcification and divided them into 3 equal groups of: mild, moderate, and severe calcification. The accuracy of coronary CTA was defined as the difference between the measurements obtained on coronary CTA versus the reference of intravascular ultrasound (IVUS). We evaluated 252 coronary calcifications within 97 arteries of 60 patients. There was an expected increase in size and density values for mild versus moderate versus severe calcifications, but there was no difference in IVUS measured minimum lumen area among the 3 groups. Of note, coronary CTA significantly underestimated IVUS minimum lumen area measurement by 1.2 ± 1.6 mm2 (14.6 ± 23.1%, P < 0.001) for severe calcifications and by 0.5 ± 2.0 mm2 (3.7 ± 32.1%, P = 0.021) for moderate calcifications. Within mild calcifications, the difference was not significant. Conclusion Based on their dimensional and radiodensity characteristics, our analysis revealed patterns of individual coronary artery calcifications that affected the accuracy of coronary CTA measurements; coronary CTA inaccuracy was associated with the presence of moderate or severe calcifications, but not mild calcifications.



  2. Diffusion Tensor Imaging of Lumbar Vertebras in Female Adolescent Idiopathic Scoliosis: Initial Findings
    imageObjective The purpose of this study was to characterize diffusion tensor imaging (DTI) features of lumbar vertebras in adolescent idiopathic scoliosis (AIS) patients. Methods Fifty-two AIS patients and 20 healthy volunteers underwent 3-T magnetic resonance scanning including DTI sequence. The fractional anisotropy (FA) and apparent diffusion coefficient (ADC) values on the convex and concave sides of lumbar vertebras were obtained and compared. Results The FA and ADC values differed significantly between the convex and concave side of lumbar vertebras in AIS (P < 0.01). The ADC values in AIS differed significantly with healthy volunteers (P < 0.01). The FA values on the convex side of L1 to L2 were significantly lower than L4 to L5 in AIS. The difference of FA values between the concave and convex sides of the apex vertebra correlated significantly with Cobb angle (r = 0.436, P < 0.01). Conclusions The convex and concave sides of lumbar vertebras in AIS patients showed different DTI features.



  3. Petamenophis (Padiamenemipet), an Egyptian Child Mummy Protected for Eternity: Revelation by Multidetector Computed Tomography
    imageObjective The objective of our work was to report the most recent findings obtained with multidetector computed tomography of a child mummy from the Roman period (119–123 CE) housed at the Egyptian Museum in Turin, Italy. Methods Multidetector computed tomography and postprocessing were applied to understand the embalming techniques, the nature of a foreign object, and anthropometrical values. The information was compared with that from other mummies that were buried in the same tomb, but today housed in different museums. Results New information regarding the embalming technique was revealed. Multidetector computed tomography allowed the identification of a knife-like metallic object, probably an amulet for the child's protection in the afterlife. Conclusions Multidetector computed tomography and image postprocessing confirm their valuable role in noninvasive studies in ancient mummies and provided evidence of a unique cultural practice in the late history of Ancient Egypt such as placing a knife possibly as an amulet.



  4. Monitoring Dynamic Morphological Changes With Electrocardiography-Gated Dynamic 4-Dimensional Computed Tomography Angiography to Predict Intraoperative Rupture of Intracranial Aneurysms
    imageObjective This study aims to evaluate dynamic morphological changes of intracranial aneurysms to predict intraoperative aneurysm rupture (IAR) during clipping. Methods Included in this study were 153 patients, who had ruptured and microsurgical-clipped aneurysms. All patients underwent dual-source computed tomography examination of electrocardiography-gated dynamic 4-dimensional computed tomography angiography before clipping. Original scanning data were reconstructed to produce 20 data sets of cardiac cycles with 5% time intervals. The aneurysm neck, transverse and longitudinal diameters, and volume from the 20 groups of images were measured to calculate their respective change rates. In addition, other data and clinical characteristics were recorded. Data were analyzed by logistic regression to identify factors associated with IAR. Results Of the 153 patients, 24 patients experienced IAR. Multivariable analysis revealed that the aneurysm neck change rate (P = 0.0001; odds ratio, 1.276) and aspect ratio (height/neck ratio, P = 0.025; odds ratio, 2.387) are predictors for IAR. When the change rate was greater than or equal to 60%, and the sensitivity and specificity were 91.7% and 76.7%, respectively. Conclusions Aneurysm neck change rate is independent predictor of IAR.



  5. Computed Tomography Image Quality Evaluation of a New Iterative Reconstruction Algorithm in the Abdomen (Adaptive Statistical Iterative Reconstruction–V) a Comparison With Model-Based Iterative Reconstruction, Adaptive Statistical Iterative Reconstruction, and Filtered Back Projection Reconstructions
    imageObjective The purpose of this study was to compare abdominopelvic computed tomography images reconstructed with adaptive statistical iterative reconstruction–V (ASIR-V) with model-based iterative reconstruction (Veo 3.0), ASIR, and filtered back projection (FBP). Methods and Materials Abdominopelvic computed tomography scans for 36 patients (26 males and 10 females) were reconstructed using FBP, ASIR (80%), Veo 3.0, and ASIR-V (30%, 60%, 90%). Mean ± SD patient age was 32 ± 10 years with mean ± SD body mass index of 26.9 ± 4.4 kg/m2. Images were reviewed by 2 independent readers in a blinded, randomized fashion. Hounsfield unit, noise, and contrast-to-noise ratio (CNR) values were calculated for each reconstruction algorithm for further comparison. Phantom evaluation of low-contrast detectability (LCD) and high-contrast resolution was performed. Results Adaptive statistical iterative reconstruction–V 30%, ASIR-V 60%, and ASIR 80% were generally superior qualitatively compared with ASIR-V 90%, Veo 3.0, and FBP (P < 0.05). Adaptive statistical iterative reconstruction–V 90% showed superior LCD and had the highest CNR in the liver, aorta, and, pancreas, measuring 7.32 ± 3.22, 11.60 ± 4.25, and 4.60 ± 2.31, respectively, compared with the next best series of ASIR-V 60% with respective CNR values of 5.54 ± 2.39, 8.78 ± 3.15, and 3.49 ± 1.77 (P <0.0001). Veo 3.0 and ASIR 80% had the best and worst spatial resolution, respectively. Conclusions Adaptive statistical iterative reconstruction–V 30% and ASIR-V 60% provided the best combination of qualitative and quantitative performance. Adaptive statistical iterative reconstruction 80% was equivalent qualitatively, but demonstrated inferior spatial resolution and LCD.


  6. High-Pitch Coronary Computed Tomographic Angiography Using the Third-Generation Dual-Source Computed Tomography: Initial Experience in Patients With High Heart Rate
    imageObjective This study aimed to evaluate the feasibility, image quality, and radiation dose of prospectively high-pitch coronary computed tomographic (CT) angiography in patients with high heart rates (HRs) using the third-generation dual-source CT. Methods One hundred consecutive patients with sinus rhythm and HR between 70 and 100 beats per minute were enrolled into this study. All patients were divided into 2 groups. Patients in group A (n = 46) were examined with prospectively high-pitch scan mode in which image acquisition was triggered at 30% of the R-R interval. Patients in group B (n = 54) were scanned with prospectively sequential mode, and the acquisition window was set at 30% to 50% of the R-R interval. Objective and subjective evaluations were performed. Diagnostic ratios and radiation dose were compared between the 2 groups. Results No statistical differences were found in objective parameters and subjective assessment of image quality between the 2 groups. Diagnostic ratios were as follows: 89.1% vs 94.4% (patient based), 95.1% vs 97.7% (vessel based), and 97.8% vs 98.8% (segment based) for group A and group B, respectively (all P > 0.05). Radiation dose was significantly lower in group A (0.53 ± 0.14 mSv) as compared with group B (1.33 ± 0.17 mSv; P < 0.01). Conclusions For patients with high HR and without cardiac arrhythmia, the prospectively high-pitch spiral acquisition using third-generation dual-source CT at systolic phase can provide images with comparatively high diagnostic ratio and significantly lower radiation dose as compared with prospectively sequential acquisition mode.



  7. Adaptive Statistical Iterative Reconstruction–V Versus Adaptive Statistical Iterative Reconstruction: Impact on Dose Reduction and Image Quality in Body Computed Tomography
    imageObjective The aim of this study was to evaluate the impact on dose reduction and image quality of the new iterative reconstruction technique: adaptive statistical iterative reconstruction (ASIR-V). Methods Fifty consecutive oncologic patients acted as case controls undergoing during their follow-up a computed tomography scan both with ASIR and ASIR-V. Each study was analyzed in a double-blinded fashion by 2 radiologists. Both quantitative and qualitative analyses of image quality were conducted. Results Computed tomography scanner radiation output was 38% (29%–45%) lower (P < 0.0001) for the ASIR-V examinations than for the ASIR ones. The quantitative image noise was significantly lower (P < 0.0001) for ASIR-V. Adaptive statistical iterative reconstruction–V had a higher performance for the subjective image noise (P = 0.01 for 5 mm and P = 0.009 for 1.25 mm), the other parameters (image sharpness, diagnostic acceptability, and overall image quality) being similar (P > 0.05). Conclusions Adaptive statistical iterative reconstruction–V is a new iterative reconstruction technique that has the potential to provide image quality equal to or greater than ASIR, with a dose reduction around 40%.



  8. A Preliminary Study of Computed Tomography Coronary Angiography Within a Single Cardiac Cycle in Patients With Atrial Fibrillation Using 256-Row Detector Computed Tomography
    imageObjective The purpose of this study was to evaluate the image quality and radiation dose of computed tomography (CT) coronary angiography using a 256-row detector CT scanner in a single cardiac cycle in patients with atrial fibrillation (AF). Methods Seventy consecutive patients (41 men and 29 women; age range was from 37 to 84 years, mean age was 61.7 ± 10.2 years; body mass index range was from 15.08 to 36.45 kg/m2, mean body mass index was 25.9 ± 3.5 kg/m2) with persistent or paroxysmal AF during acquisition, who were not receiving any medications for heart rate (HR) regulation, were imaged with a 256-row detector CT scanner (Revolution CT, GE healthcare). According to the HR or HR variability (HRV) the patients were divided into 4 groups: group A (HR, ≥75 bpm; n = 36), group B (HR, <75 bpm; n = 34), group C (HRV, ≥50 bpm; n = 26), and group D (HRV, <50 bpm; n = 44). The snapshot freeze algorithm reconstruction was used to reduce motion artifacts whenever necessary. Two experienced radiologists, who were blinded to the electrocardiograph and reconstruction information, independently graded the CT images in terms of visibility and artifacts with a 4-grade rating scale (1, excellent; 2, good; 3, poor; 4, insufficient) using the 18-segment model. Subjective image quality scores and effective dose (ED) were calculated and compared between these groups. Results The HR during acquisition ranged from 47 to 222 bpm (88.24 ± 36.80 bpm). A total of 917 in 936 coronary artery segments were rated as diagnostically evaluable (98.2 ± 0.04%). There was no significant linear correlation between mean image quality and HR or HRV (P > 0.05). Snapshot freeze reconstruction technique was applied in 28 patients to reduce motion artifacts and thus showed image quality was improved from 93.2% to 98.4%. The ED was 3.05 ± 2.23 mSv (0.49–11.86 mSv) for all patients, and 3.76 ± 2.22 mSv (0.92–11.17 mSv), 2.30 ± 2.02 mSv (0.49–11.86 mSv), 3.89 ± 2.35 mSv (1.18–11.86 mSv), and 2.56 ± 2.03 mSv (0.49–11.17 mSv) for groups A, B, C, and D, respectively. There were significant differences in mean ED between groups A and B, as well as C and D (P <0.05). Conclusions This study shows that CT coronary angiography with use of a new 256-row detector CT in single cardiac cycle achieves diagnostic image quality but with lower radiation dose in patients with AF. Heart rate or HRV has no significant effect on image quality.



  9. Clinically Acceptable Optimized Dose Reduction in Computed Tomographic Imaging of Necrotizing Pancreatitis Using a Noise Addition Software Tool
    imageObjective This study aimed to determine potential radiation dose reduction of contrast-enhanced computed tomography (CECT) for imaging necrotizing pancreatitis (NP) using a noise addition tool. Methods Eighty-four patients were identified with at least 1 abdominopelvic CECT for NP within a 2-year period. Sixty consecutive scans were selected as reference radiation dose data sets. A noise addition software was used to simulate 4 data sets of increased noise. Readers rated confidence for identifying (i) anatomic structures, (ii) complications of NP, and (iii) diagnostic acceptability. Noise and dose levels were identified at acceptability threshold where observer scores were statistically indistinguishable from full-dose computed tomographies. Results Observers' perception of image tasks decreased progressively with increasing noise (P < 0.05). Acceptability and statistical analysis indicated that noise can be increased from 10 to 25 HU corresponding to an 84% reduction in dose without change in observer perception (P < 0.05). Conclusions Higher image noise levels may be tolerated in CECT in patients with NP.



  10. Computed Tomography-Based Texture Analysis to Determine Human Papillomavirus Status of Oropharyngeal Squamous Cell Carcinoma
    imageObjective To determine whether machine learning can accurately classify human papillomavirus (HPV) status of oropharyngeal squamous cell carcinoma (OPSCC) using computed tomography (CT)-based texture analysis. Methods Texture analyses were retrospectively applied to regions of interest from OPSCC primary tumors on contrast-enhanced neck CT, and machine learning was used to create a model that classified HPV status with the highest accuracy. Results were compared against the blinded review of 2 neuroradiologists. Results The HPV-positive (n = 92) and -negative (n = 15) cohorts were well matched clinically. Neuroradiologist classification accuracies for HPV status (44.9%, 55.1%) were not significantly different (P = 0.13), and there was a lack of agreement between the 2 neuroradiologists (κ = −0.145). The best machine learning model had an accuracy of 75.7%, which was greater than either neuroradiologist (P < 0.001, P = 0.002). Conclusions Useful diagnostic information regarding HPV infection can be extracted from the CT appearance of OPSCC beyond what is apparent to the trained human eye.


  11. Diagnostic Accuracy of Qualitative and Quantitative Computed Tomography Analysis for Diagnosis of Pathological Grade and Stage in Upper Tract Urothelial Cell Carcinoma
    imageObjective The aim of this study was to compare grade and stage of upper tract urothelial cell carcinoma (UCC) using computed tomography. Materials and Methods With institutional review board approval, 48 patients with 49 UCC (44 high grade and 5 low grade, 26 ≤ T1 and 23 ≥ T2) underwent nephroureterectomy and preoperative computed tomography between 2013 and 2015. Two blinded radiologists assessed for tumor appearance (filling defect/mass or wall thickening/stricture), margin (smooth or spiculated/irregular), texture (homogeneous, heterogeneous), hydronephrosis, and calcification. A third blinded radiologist established consensus. A fourth blinded radiologist measured size and first-order histogram texture features. Comparisons were performed using χ2 test, multivariable logistic regression, and receiver operator characteristic analysis. Results There was no difference in size of tumors compared by grade or stage (P = 0.80 and 0.13, respectively). Among subjective variables, only tumor texture was significantly different between low- and high-grade UCC (P = 0.03; κ = 0.45). Tumors characterized as spiculated/irregular margin (P = 0.003; 0.30) and heterogeneous (P < 0.001; κ = 0.45) were associated with T2 disease or higher. Entropy was greater in higher grade (6.23 ± 0.46 vs 5.72 ± 0.28) and T2 disease or higher (6.40 ± 0.33 vs 5.95 ± 0.48), (P = 0.03 and 0.02, respectively) with no differences in Kurtosis or Skewness (P > 0.05). Area under the receiver operator characteristic curve for entropy to diagnose high-grade and T2 tumors or higher was 0.83 (confidence interval, 0.64–1.0) and 0.79 (confidence interval 0.59–0.98), respectively. Conclusions Heterogeneity, assessed qualitatively and quantitatively, is accurate for diagnosis of higher grade and stage of disease in upper tract UCC. Spiculated/irregular margins are also associated with T2 disease or higher.



  12. Magnetic Resonance Imaging of the Soft Tissue Vascular Anomalies in Torso and Extremities in Children: An Update With 2014 International Society for the Study of Vascular Anomalies Classification
    imageVascular anomalies can occur anywhere in the body, and the majority present in the pediatric population. Accurate classification is essential for proper clinical evaluation, particularly because multidisciplinary care is often required. The International Society for the Study of Vascular Anomalies classification offers a comprehensive classification for all subspecialties. In this review article, we present a magnetic resonance imaging protocol with exemplary cases of the most common types of vascular anomalies in the pediatric trunk and extremities using the current International Society for the Study of Vascular Anomalies classification.



  13. Performance of Magnetic Resonance Susceptibility-Weighted Imaging for Detection of Calcifications in Patients With Hepatic Echinococcosis
    imageObjective We evaluated the performance of susceptibility-weighted imaging (SWI) for identification of hepatic calcifications in alveolar echinococcosis and cystic echinococcosis. Methods The SWI images of 58 lesions in 40 patients (age, 49 ± 14 y) with alveolar echinococcosis (n = 22) or cystic echinococcosis (n = 18) were reviewed for calcifications. First, calcifications were suggested by visual assessment. Second, ratios of minimum intralesional intensity and mean lumbar muscle intensity were recorded. Computed tomography (CT) served as the criterion standard. Results Thirty-seven lesions showed calcifications on CT. Susceptibility-weighted imaging provided a sensitivity of 89.2% (95% confidence interval [CI], 50.1–75.7) and a specificity of 57.1% (95% CI, 34.4–77.4) for calcifications detected by visual assessment. Receiver operating characteristic curves demonstrated a sensitivity of 67.6% and a specificity of 85.0% for an intensity ratio of 0.61. A specificity of 100% (95% CI, 80.8–100) and a sensitivity of 84.5% (95% CI, 67.3–93.2) were achieved by SWI for calcifications with a density greater than 184 HU in CT. Conclusions Identification of hepatic calcifications is possible with SWI. Susceptibility-weighted imaging offers the potential to reduce the need for of CT imaging for evaluation of echinococcosis.



  14. Noninvasive Computed Tomography–Derived Fractional Flow Reserve Based on Structural and Fluid Analysis: Reproducibility of On-site Determination by Unexperienced Observers
    imageObjective The aim of this study was to evaluate the reproducibility of computed tomography (CT)–derived fractional flow reserve (FFR) determined on site by inexperienced observers using a postprocessing software based on structural and fluid analysis. Methods Using 21 coronary vessels in 7 patients who underwent 320-row coronary CT angiography and catheter-FFR, 2 independent inexperienced observers (A: a student radiation technologist; B: a nonmedical staff) determined the CT-FFR using a postprocessing software. After a 20-minute training session, both observers postprocessed all vessels and readjusted their settings after another training/feedback. These CT-FFRs were compared with values determined by an expert analyst. Results The mean processing times were 23 ± 4 minutes (automatic), 71 ± 5 minutes (observer A), and 57 ± 7 minutes (observer B) per patient. The initial correlations with expert data were r = 0.92 (observer A) and 0.73 (observer B) and increased to 0.83 for observer B after additional training. The final absolute difference with the expert data was 0.000 to 0.020. The correlation between catheter-FFR and expert CT-FFR was r = 0.76. Conclusions The CT-derived FFR on-site postprocessing software showed good reproducibility for measurements by inexperienced observers.



  15. Augmented Quadruple-Phase Contrast Media Administration and Triphasic Scan Protocol Increases Image Quality at Reduced Radiation Dose During Computed Tomography Urography
    imagePurpose The aim of this article was to investigate the opacification of the renal vasculature and the urogenital system during computed tomography urography by using a quadruple-phase contrast media in a triphasic scan protocol. Materials and Methods A total of 200 patients with possible urinary tract abnormalities were equally divided between 2 protocols. Protocol A used the conventional single bolus and quadruple-phase scan protocol (pre, arterial, venous, and delayed), retrospectively. Protocol B included a quadruple-phase contrast media injection with a triphasic scan protocol (pre, arterial and combined venous, and delayed), prospectively. Each protocol used 100 mL contrast and saline at a flow rate of 4.5 mL. Attenuation profiles and contrast-to-noise ratio of the renal arteries, veins, and urogenital tract were measured. Effective radiation dose calculation, data analysis by independent sample t test, receiver operating characteristic, and visual grading characteristic analyses were performed. Results In arterial circulation, only the inferior interlobular arteries in both protocols showed a statistical significance (P < 0.05). Venously, the inferior vena cava, proximal and distal renal veins demonstrated a significant opacification reduction in protocol B than in protocol A (P < 0.001). Protocol B showed a significantly higher mean contrast-to-noise ratio than protocol A (protocol B: 22.68 ± 13.72; protocol A: 14.75 ± 5.76; P < 0.001). Radiation dose was significantly reduced in protocol B (7.38 ± 2.22 mSv) than in protocol A (12.28 ± 2.72 mSv) (P < 0.001). Visual grading characteristic (P < 0.027) and receiver operating characteristic (P < 0.0001) analyses demonstrated a significant preference for protocol B. Conclusions In computed tomography urography, augmented quadruple-phase contrast media and triphasic scan protocol usage increases the image quality at a reduced radiation dose.


  16. Iterative Metallic Artifact Reduction for In-Plane Gonadal Shielding During Computed Tomographic Venography of Young Males
    imageObjective The purpose of this study was to evaluate a gonadal shield (GS) and iterative metallic artifact reduction (IMAR) during computed tomography scans, regarding the image quality and radiation dose. Methods A phantom was imaged with and without a GS. Prospectively enrolled, young male patients underwent lower extremity computed tomography venography (precontrast imaging without the GS and postcontrast imaging with the GS). Radiation dose was measured each time, and the GS-applied images were reconstructed by weighted filtered back projection and IMAR. Results In the phantom study, image artifacts were significantly reduced by using IMAR (P = 0.031), whereas the GS reduced the radiation dose by 61.3%. In the clinical study (n = 29), IMAR mitigated artifacts from the GS, thus 96.6% of the IMAR image sets were clinically usable. Gonadal shielding reduced the radiation dose to the testes by 69.0%. Conclusions The GS in conjunction with IMAR significantly reduced the radiation dose to the testes while maintaining the image quality.



  17. Quantification of Iodine Concentration Using Single-Source Dual-Energy Computed Tomography in a Calf Liver
    imageObjective To evaluate the accuracy of single-source dual-energy computed tomography (ssDECT) in iodine quantification using various segmentation methods in an ex vivo model. Methods Ten sausages, injected with variable quantities of iodinated contrast, were inserted into 2 livers and scanned with ssDECT. Material density iodine images were reconstructed. Three radiologists segmented each sausage. Iodine concentration, volume, and absolute quantity were measured. Agreement between the measured and injected iodine was assessed with the concordance correlation coefficient (CCC). Intrareader agreement was assessed using the intraclass correlation coefficient (ICC). Results Air bubbles were observed in sausage (IX). Sausage (X) was within the same view as hyper-attenuating markers used for localization. With IX and X excluded, CCC and ICC were greater than 0.98 and greater than 0.88. When included, CCC and ICC were greater than 0.94 and greater than 0.79. Conclusions Iodine quantification was reproducible and precise. However, accuracy reduced in sausages consisting of air filled cavities and within the same view as hyperattenuating markers.



  18. The Significance of Arachnoid Granulation in Patients With Idiopathic Intracranial Hypertension
    imagePurpose The aim of this article was to study the significance of arachnoid granulations (AGs) in patients with idiopathic intracranial hypertension (IIH). Methods In an institutional review board–approved retrospective chart review study, 79 patients with clinical diagnosis of idiopathic increased intracranial pressure were compared with 63 patients with a diagnosis of multiple sclerosis. Inclusion criteria also included available magnetic resonance imaging (MRI) of the brain, older than 18 years, and female sex. Patients with elevated intracranial pressure due to other causes were excluded. The electronic medical records were mined for presence of the following: body mass index, age, headache, vision changes, tinnitus, and vertigo. The MRI of the brain was reviewed for the presence of the following features: empty sella, prominent cerebrospinal fluid space in the optic sheaths, tortuosity of the optic nerves and enlarged Meckel cave. In addition, the number, size, and location of AGs associated with major venous drainage sinuses were documented in all patients. Using statistical analysis, association between various imaging and clinical signs were evaluated. Results The association between AG and various imaging and clinical signs were evaluated. The percentage of patients with AG were significantly higher in patients with IIH. Patients with IIH tended to have 0 to 3 AG. The most common imaging findings observed in MRI of the brain of patients with IIH were empty sella and prominent cerebrospinal fluid space in the optic sheaths. The prevalence of these MRI findings in patients with IIH was inversely proportional to the number of AG. A similar inverse trend was also noted with the opening pressure of patients with IIH and number of AG. Conclusions The study establishes that there is a relationship between presence of AG and IIH. Arachnoid granulation seems to act in a compensatory mechanism in patients with IIH.



  19. Focal Hepatic Glycogenosis in a Patient With Uncontrolled Diabetes Mellitus Type 1
    imageHepatomegaly and elevated liver enzymes in patients with diabetes are commonly associated with fatty liver disease. However, physicians often forget about another intrinsic substance that can cause a similar clinical picture—glycogen. Liver stores approximately one third of the total body glycogen and is responsible for blood glucose homeostasis. Excessive hepatocellular glycogen accumulation occurs not only in congenital glycogen storage diseases, but also in acquired conditions associated with hyperglycemic-hyperinsulinemic states such as uncontrolled diabetes mellitus, high-dose corticosteroid use, and dumping syndrome. All reported cases of acquired abnormal glycogen deposition described a diffuse form of hepatic glycogenosis with the entire liver involved in the accumulating process. To our knowledge, this is the first reported case of abnormal focal glycogen deposition in a patient with diabetes mellitus type 1 with imaging and pathologic correlation. Awareness of the imaging appearance of focal glycogen deposition can help to distinguish it from other pathologic conditions.



  20. Characterizing Intraorbital Optic Nerve Changes on Diffusion Tensor Imaging in Thyroid Eye Disease Before Dysthyroid Optic Neuropathy
    imageObjective The aim of this study was to determine whether the optic nerve is affected by thyroid eye disease (TED) before the development of dysthyroid optic neuropathy with diffusion-tensor imaging (DTI). Methods Twenty TED patients and 20 controls were included. The mean, axial, and radial diffusivities and fractional anisotropy (FA) value were measured at the optic nerves in DTI. Extraocular muscle diameters were measured on computed tomography. The diffusivities and FA of the optic nerves were compared between TED and controls and between active and inactive stages of TED. The correlations between these DTI parameters and the clinical features were determined. Results The mean, axial, and radial diffusivities were lower in TED compared with the controls (P < 0.05). In contrast, FA was higher in TED (P = 0.001). Radial diffusivity was lower in the active stage of TED than the inactive stage (P = 0.035). The FA was higher in the TED group than in the control group (P = 0.021) and was positively correlated with clinical activity score (r = 0.364, P = 0.021), modified NOSPECS score (r = 0.469, P = 0.002), and extraocular muscle thickness (r = 0.325, P = 0.041) in the TED group. Radial diffusivity was negatively correlated with modified NOSPECS score (r = −0.384, P = 0.014), and axial diffusivity was positively correlated with exophthalmos degree (r = 0.363, P = 0.025). Conclusions The diffusivities and FA reflected changes in the optic nerve before dysthyroid optic neuropathy in TED. The FA, in particular, reflected TED activity and severity.


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