Current Medical Imaging - Volume 15, Issue 5, 2019

Background: Fat can be identified in numerous liver lesions, and usually is not a specific finding. Distinguishing between different kinds of fatty deposits is an important part of differential diagnosis. Magnetic Resonance Imaging (MRI) is superior to other imaging techniques because it allows distinguishing intracellular from macroscopic fat. Discussion: Intracellular lipid may be found in focal hepatic steatosis, hepatic adenoma, hepatocellular carcinoma and, less commonly, in focal nodular hyperplasia as well as regenerative and dysplastic nodules. Macroscopic fat is seen in angiomyolipoma, lipoma, metastases from fatcontaining neoplasms, primary or metastatic liposarcoma, hydatid cyst, pseudolipoma of the Glisson capsule, pericaval fat collection, lipopeliosis, hepatic teratoma, focal hepatic extramedullary haematopoiesis and adrenal rest tumour. Conclusion: Liver nodules should be characterised with regard to underlying liver condition, MRI characteristics and contrast enhancement pattern, including hepatobiliary phase. In many cases, identification of fatty content may help narrowing the differential diagnosis.

Background: This review aims to identify the development of the algorithms for brain tissue and structure segmentation in MRI images. Discussion: Starting from the results of the Grand Challenges on brain tissue and structure segmentation held in Medical Image Computing and Computer-Assisted Intervention (MICCAI), this review analyses the development of the algorithms and discusses the tendency from multi-atlas label fusion to deep learning. The intrinsic characteristics of the winners’ algorithms on the Grand Challenges from the year 2012 to 2018 are analyzed and the results are compared carefully. Conclusion: Although deep learning has got higher rankings in the challenge, it has not yet met the expectations in terms of accuracy. More effective and specialized work should be done in the future.

Background: The aim of this study is to perform a systematic review of the feasibility and clinical application of double low-dose CT pulmonary angiography (CTPA) in the diagnosis of patients with suspected pulmonary embolism. Discussion: A total of 13 studies were found to meet selection criteria reporting both low radiation dose (70 or 80 kVp versus 100 or 120 kVp) and low contrast medium dose CTPA protocols. Lowdose CTPA resulted in radiation dose reduction from 29.6% to 87.5% in 12 studies (range: 0.4 to 23.5 mSv), while in one study, radiation dose was increased in the dual-energy CT group when compared to the standard 120 kVp group. CTPA with use of low contrast medium volume (range: 20 to 75 ml) was compared to standard CTPA (range: 50 to 101 ml) in 12 studies with reduction between 25 and 67%, while in the remaining study, low iodine concentration was used with 23% dose reduction achieved. Quantitative assessment of image quality (in terms of signal-to-noise ratio and contrast-to-noise ratio) showed that low-dose CTPA was associated with higher, lower and no change in image quality in 3, 3 and 6 studies, respectively when compared to the standard CTPA protocol. The subjective assessment indicated similar image quality in 11 studies between low-dose and standard CTPA groups, and improved image quality in 1 study with low-dose CTPA. Conclusion: This review shows that double low-dose CTPA is feasible in the diagnosis of pulmonary embolism with significant reductions in both radiation and contrast medium doses, without compromising diagnostic image quality.

Background: Parkinson’s Disease (PD) is caused by the deficiency of dopamine, the neurotransmitter that has an effect on specific uptake region of the substantia nigra. Identification of PD is quite tough at an early stage. Objective: The present work proposes an expert system for three dimensional Single-Photon Emission Computed Tomography (SPECT) image to diagnose the early PD. Methods: The transaxial image slices are selected on the basis of their high specific uptake region. The processing techniques like preprocessing, segmentation and feature extraction are implemented to extract the quantification parameters like Intensity, correlation, entropy, skewness and kurtosis of the images. The Support Vector Machine (SVM) and Extreme Learning Machine (ELM) classifiers using Radial Basis Function kernel (RBF) are implemented and their results are compared in order to achieve better performance of the system. The performance of the system is evaluated in terms of sensitivity, specificity analysis, accuracy, Receiver Operating Curve (ROC) and Area Under the Curve (AUC). Results: It is found that RBF-ELM provides high accuracy of 98.2% in diagnosing early PD. In addition, the similarity among the features is found out using K-means clustering algorithm to compute the threshold level for early PD. The computed threshold level is validated using Analysis of Variance (ANOVA). Conclusion: The proposed system has a great potential to assist the clinicians in the early diagnosis process of PD.

Background: In past magnetic resonance imaging studies, normal participants and schizophrenia patients have usually been compared using imaging processing modes with only one parameter. A more extensive evaluation of significant differences between gray and white matter in Schizophrenic patents was necessary. Methods: Voxel based morphometry was used to separate brain images into gray matter and white matter. Then, the images were mapped to Montreal Neurological Institute space, and DARTEL analytic template was applied for image calibration with statistical parametric mapping. Finally, joint independent component analysis was employed to analyze the gray and white matter of brain images from Schizophrenic patients and normal controls. In this study, joint independent component analysis was used to discriminate clinical differences in magnetic resonance imaging signals between Schizophrenic patients and normal controls. Results: Region of interest analyses has repeatedly shown gray matter reduction in the superior temporal gyrus of Schizophrenic patients. Conclusion: These results strongly support previous studies regarding brain volume in schizophrenic patients. The connection networks in frontal and temporal lobes evidently did not differ between normal participants and schizophrenia patients.

Background: We investigated thoracic masses with Computed Tomography (CT)- guided Percutaneous Co-Axial Trans-Thoracic Biopsy (PCTTB). Methods: The retrospective data of 86 patients to whom CT-guided PCTTB had been applied were obtained. Eighty-four cases and their pathologic results were included in the study. Localization and appearance of the lesions, pathologic results, and complications were evaluated. Results: Diagnostic sensitivity of CT-guided PCTTB was 97.6%. In 60.7% of the cases, malign lesions and, in 39.3% of the cases, benign lesions were diagnosed. The mass size was on average greater than 2 cm, and one mass was detected as being more than ≥2 masses. Mainly, irregular contours were observed. Most of the malign tumors were primary malign tumors on both sides (91.7% on the right side and 88.9% on the left side). Squamous Cell Carcinoma (SCC) was the most often detected malign tumor on the right side, and adenocarcinoma was the most often detected malign tumor on the left side. In masses localized on the left inferior lobe, metastasis was often detected. When the number of the mass was ≥2 and the mass had the appearance of consolidation, metastasis was usually detected. Small and large masses were mainly localized on right and left upper lobes. In the small mass group, 75.0% of the cases were benign, and, in the large mass group, 64.5% of the cases were malign (p=0.031, χ2=4.666). Pneumothorax was the most commonly occurring complication (23.8%). In masses localized on the right lower lobe, the pneumothorax ratio increased in benign masses compared to malign masses. The hemorrhage detection rate was 13.0%, and hemoptysis occurred in 14.2% of the cases. Hemorrhage was detected during 11.8% of the large mass biopsies. In females, hemorrhage occurred more often than in males (p=0.026, r= 0.244). Conclusion: CT-guided PCTTB is a safe method to utilize for lung biopsies. Co-axial method increased the diagnostic accuracy of CT-guided percutaneous trans-thoracic biopsies. A single cut also decreased the complication rates.

Background: To compare the abilities of ultrasonography (US) and Computed Tomography (CT) to identify calcifications and to predict probability of malignancy for Papillary Thyroid Carcinoma (PTC) and Papillary Thyroid Microcarcinoma (PTMC). Methods: We reviewed 1008 cases of PTC/PTMC with calcifications reported by pre-operative US, CT, or post-operative pathology. The size of the thyroid nodule was obtained from the US report and the maximum diameter (d) was documented. According to the nodule size (d), the PTC and PTMC groups were each divided into two subgroups, as follows: large PTC group (d ≥ 2 cm), small PTC group (1 cm < d < 2 cm), large PTMC group (0.6 cm ≤ d ≤ 1 cm), and small PTMC group (d < 0.6 cm). Results: In the 1008 patients, the ratio of females to males was 2.29 and the mean age was 40.9 years (standard deviation: 11.7 years). Of the 1008 records, 92.8% were found to have calcifications according to the US report, while 50.4% showed calcifications according to the CT report. This difference between US and CT reports was statistically significant (p < 0.0005). The percentages of US reports showing calcifications were similar for all four PTC and PTMC subgroups (93.7%, 94.3%, 92.1%, and 85.1%, respectively; p = 0.052), while the percentages of CT reports showing calcifications were significantly different among the PTC and PTMC subgroups (62.3%, 52.2%, 45.4%, and 31.3%, respectively; p < 0.0005). As for the prediction of malignancy, US was superior to CT in all four subgroups (large PTC group: 97.1% vs. 54.1%, small PTC group: 94.8% vs. 42.9%, large PTMC group: 97.2% vs. 32.0%, small PTMC group: 95.5% vs. 14.9%; p < 0.0005 for all pairwise comparisons). No significant difference was observed in terms of the ability of US to predict the malignancy of PTC versus PTMC (p = 0.31), while CT showed significant superiority in diagnosing PTC versus PTMC (p < 0.0005). The predictive value of CT for PTC declined as the nodule size decreased (p < 0.05 for all pairwise comparisons). Conclusion: Our results showed that US detected calcifications and predicted the malignancy of all nodule sizes of thyroid papillary carcinoma equally well, while the performance of CT declined with the reduction of nodule size.

Background: CT Angiography (CTA) of aortoiliac and lower extremity arteries is a relatively recent innovation of CT imaging that has changed after the introduction of multi-detector row scanners. Objective: The study aimed to evaluate the diagnostic accuracy of Multidetector Computed Tomographic Angiography (MDCTA) in the assessment of arterial tree in patients with Peripheral Arterial Occlusive Disease (PAOD), as compared to Digital Subtraction Angiography (DSA). Methods: A single-center nonrandomized prospective study was conducted on 50 patients complaining of peripheral arterial disease (chronic stage) from February 2017 to October 2017. All the patients were exposed to DSA and CTA prior to definitive treatment. The images were then analyzed using maximum intensity projection, volume-rendered, and curved multiplane reformation techniques. Results: All the patients involved in this study were susceptible according to their clinical presentation. The statistical analysis exposed a highly significant difference between CTA and DSA in the assessment of stenosis at the level of Femoropopliteal segment (P<0.01), while for infrapopliteal segment, there was no statistically significant difference between CTA and DSA having 8% versus 14% insignificant stenosis and 62% versus 47% significant stenosis in CTA and DSA, respectively. The overall accuracy of CT angiography in the femoropopliteal segments was 95.20% while in the infrapopliteal segment it was 94.5%. Conclusion: Multidetector CT angiography was found to be a reliable alternative mean for pathoanatomical description of the arterial lesions in critical lower limb ischemia and its subsequent management in comparison to digital subtraction angiography.

Background: Intraductal papillary mucinous neoplasms (IPMNs) are among the important premalignant lesions. Early detection and intervention are critical to positive patient outcomes. Magnetic resonance imaging (MRI) can be used to evaluate the malignancy of IPMNs, and magnetic resonance cholangiopancreatography (MRCP) is recommended for follow-up of pancreatic cystic lesions. Objective: To evaluate the diagnostic performance of MRI combined with MRCP in determining the malignant potential of pancreas IPMN. Methods: This is a retrospective study of 55 patients with 58 pancreatic lesions confirmed after surgery, which were analyzed and divided into two groups, a benign IPMN group (n = 27) and a malignant IPMN group (n = 31). Two radiologists analyzed the high-risk stigmata and worrisome features of pancreas IPMN to evaluate the malignant potential. Score all the lesions as proposed by the international consensus guidelines 2012, and calculate the sensitivity, specificity and accuracy. Results: There were significant differences of size, enhancement of solid components, and degree of dilation of the main pancreatic duct between benign and malignant IPMN (P < 0.05). However, differences in gender, age and location of disease between the two groups were not statistically significant (P > 0.05). The sensitivity, specificity and accuracy of MRI combined with MRCP in preoperative diagnosis of malignant IPMNs were 90.3% (28/31), 70.4% (19/27) and 81.0% (47/58) respectively, when at least one worrisome feature was present. Conclusion: MRI combined with MRCP is useful in the evaluation of the benign and malignant pancreas IPMN.

Background: In the present study, we investigated the relationship between caroticovertebral Doppler USG measurement results and Vertigo Symptom Scale-Short Form (VSS-SF) in patients with idiopathic vertigo. Methods: Fifty patients with idiopathic vertigo and 30 healthy subjects were included into the study. Ear, Nose & Throat (ENT) examination, audiological examination, routine hemogram, biochemichal tests and temporal magnetic resonance imaging were performed to diagnose “idiopathic vertigo”. By carotico-vertebral Doppler ultrasonography (USG), common carotid artery (CCA) area, intima media thickness; and vertebral artery dimension were measured on the right and left side of the study and control groups. Results: CCA area values were not different between the study and control groups; and between the right and left sides of the each group. On the left side, intima media thickness and vertebral artery dimension values of the vertigo group were significantly higher than those of the control group. Correlation tests showed that CCA area and intima media thickness values on the right and left side were positively correlated with each other. Moreover, in patients with higher right; or left intima media thickness values, left vertebral artery dimensions decreased. Older age was associated with higher intima media thickness in right and left sides. When CCA values decreased on the right side, VSS-SF values increased; and patients’ complaints for vertigo got higher. Linear regression analysis (Backward LR) results also showed that the significant compounding factor on VSS-SF was right CCA area. As right CCA area decreased, VSS-SF increased with more vertigo complaints. Whereas, vertigo complaints and VSS-SF decreased when right CCA increased. Conclusion: We concluded that a decrease in the right CCA were linked with higher VSS-SF scores and increasing vertigo symptoms. Whereas, a decrease in the left CCA area and left crabial blood supply are more important related to the left hemispheric dominance in right-handed people. Moreover, an increase in the intima media thickness was also detected in the vertigo patients and it probably causes a decrease in the central blood flow.

Background: Tuberculous tenosynovitis of the wrist is rare among cases of musculoskeletal tuberculosis. It is a slow, progressive disease with silent symptoms, leading to a late diagnosis. Also, it can be misdiagnosed as inflammatory arthritis, pyogenic infections, and inflammatory tenosynovitis. Thus, patients present with destructive changes of the bone and joint, as well as abscesses, often receive incorrect or unnecessary medical and surgical treatment. Discussion: Well-documented anamneses along with physical examinations and radiologic imaging methods, such as computed tomography (CT) and magnetic resonance imaging (MRI), can be useful in the diagnosis of tuberculous tenosynovitis. All chronic synovitis of the wrist with longstanding pain should be considered as mycobacterial infection and an important differential diagnosis. Early diagnosis followed by extensive debridement and antituberculous chemotherapy provides good functional results. Conclusion: This article presents the cases of two patients with wrist tuberculous tenosynovitis and the respective MRI findings. It also includes a literature review.