Current Medical Imaging - Volume 18, Issue 13, 2022

Magnetic Resonance Imaging (MRI) is the most sensitive and advanced imaging technique in diagnosing breast cancer and is essential in improving cancer detection, lesion characterization, and determining therapy response. In addition to the dynamic contrast-enhanced (DCE) technique, functional techniques such as magnetic resonance spectroscopy (MRS), diffusion-weighted imaging (DWI), diffusion kurtosis imaging (DKI), and intravoxel incoherent motion (IVIM) further characterize and differentiate benign and malignant lesions thus, improving diagnostic accuracy. There is now an increasing clinical usage of MRI breast, including screening in high risk and supplementary screening tools in average-risk patients. MRI is becoming imperative in assisting breast surgeons in planning breast-conserving surgery for preoperative local staging and evaluation of neoadjuvant chemotherapy response. Other clinical applications for MRI breast include occult breast cancer detection, investigation of nipple discharge, and breast implant assessment. There is now an abundance of research publications on MRI Breast with several areas that still remain to be explored. This review gives a comprehensive overview of the clinical trends of MRI breast with emphasis on imaging features and interpretation using conventional and advanced techniques. In addition, future research areas in MRI breast include developing techniques to make MRI more accessible and costeffective for screening. The abbreviated MRI breast procedure and an area of focused research in the enhancement of radiologists' work with artificial intelligence have high impact for the future in MRI Breast.

Background: Advanced Modeling Iterative Reconstruction (ADMIRE) algorithm has five intensity levels; it is important to study which algorithm is better for brain CT scanning. Objective: The aim of the study is to compare the influence of different strength levels of ADMIRE and traditional Filtered Back Projection (FBP) on image quality in brain CT scanning. Methods: 60 patients were retrospectively selected, and the data from each of these patients’ brains were reconstructed by four different reconstruction methods (FBP, ADMIRE1, ADMIRE3, and ADMIRE5). A five-point Likert Scale was implemented to evaluate the subjective image quality. Image noise, CT value of brain tissue , signal-to-noise ratio (SNR) of gray white matter, contrast-to-noise ratio (CNR), and beam hardening artifact index (AI) of the posterior fossa, were measured for evaluating the objective image quality. Finally, the differences between the subjective and objective evaluations were compared. Results: There were no statistical differences observed in CT values of gray matter and white matter between the four groups (all P >0.05). The image noise gradually decreased with the increase of ADMIRE algorithm level. The AI exhibited no statistical difference between the four groups (F =0.793, P =0.499), but it tended to decrease slightly with the increase of ADMIRE algorithm level. Compared to other groups (all p <0.001), the ADMIRE5 group demonstrated the best objective image quality. Nevertheless, the highest subjective score was observed in the ADMIRE3 group, which exhibited significant differences with other images (all P <0.001). Conclusion: ADMIRE algorithm can clearly improve image quality, but it cannot significantly improve the linear sclerosis artifacts in the posterior cranial fossa. Based on the subjective evaluation of image quality, ADMIRE3 algorithm is recommended in brain CT scanning.

Aims: The purpose of this paper is to prospectively evaluate the performance of an artificial intelligence (AI) system in diagnosing thyroid nodules and to assess its potential value in comparison with the performance of radiologists with different levels of experience, as well as the factors affecting its diagnostic accuracy. Background: In recent years, medical imaging diagnosis using AI has become a popular topic in clinical application research. Objective: This study aimed to evaluate the performance of an AI system in diagnosing thyroid nodules and compare it with the performance levels of different radiologists. Methods: This study involved 426 patients screened for thyroid nodules at the First Affiliated Hospital of Guangzhou Medical University between July 2017 and March 2019. All of the nodules were evaluated by radiologists with various levels of experience and an AI system. The diagnostic performances of two junior and two senior radiologists, an AI system, and an AI-assisted junior radiologist were compared, as were their diagnostic results with respect to nodules of different sizes. Results: The senior radiologists, the AI system, and the AI-assisted junior radiologist performed better than the junior radiologist (p < 0.05). The area under the curves of the AI system and the AI-assisted junior radiologist were similar to the curve of the senior radiologists (p > 0.05). The diagnostic results concerning the two nodule sizes showed that the diagnostic error rates of the AI system, junior radiologists, and senior radiologists for nodules with a maximum diameter of ≤1 cm (Dmax ≤ 1 cm) were higher than those for nodules with a maximum diameter of 1 cm (Dmax > 1 cm) (23.4% vs. 12.1%, p = 0.002; 26.6% vs. 7.3%, p < 0.001; and 38.3% vs. 14.6%, p < 0.001). Conclusion: The AI system is a decision-making tool that could potentially improve the diagnostic efficiency of junior radiologists. Micronodules with Dmax ≤ 1cm were significantly correlated with diagnostic accuracy; accordingly, more micronodules of this size, in particular, should be added to the AI system as training samples. Other: The system could be a potential decision-making tool for effectively improving the diagnostic efficiency of junior radiologists in the community.

Objectives: To evaluate clinical data and Magnetic Resonance Venography (MRV) findings together in patients with idiopathic intracranial hypertension (IIH). Materials and Methods: In this retrospective study between January 2009 and February 2021, conventional MRI and MRV examinations were performed on 30 patients who were admitted to the neurology service of Erciyes University Medical Faculty with the pre-diagnosis of IIH, cerebrospinal fluid (CSF) pressure was measured in these patients to confirm the diagnosis of IIH. Transverse Sinus Stenosis Ratio (TS SR), Superior Sagittal Sinus (SSS) diameter, Sinus Rectus (SR) diameter, Stenosis Segment Length (SSL) were studied. Results: High CSF pressure was detected in 22 of 30 patients with IIH pre-diagnosis. CSF pressure was normal in 8 cases. TS SR was compared in all groups, right TS SR 0.63 ± 0.16, Left TS SR 0.55 ± 0.16 in the patient group with IIH, right TS SR 0.55 ±0.16 in the CSF pressure normal patient group, Right TS SR 0.28 ± 0.07 Left TS SR 0.31 ± 0.07 in the control group Right TS SR It was 0.28 ± 0.09, Sol TS SR was 0.30 ± 0.07. Conclusion: Before LP, the cranial venous system must be monitored. TS SR and CSF pressure are directly proportional. The stenosis rate is important for IIH rather than SSL.

Background: Sinus lift via the alveolar crest approach has been proven to solve inadequate alveolar bone height perfectly in the posterior region of the maxilla. Nevertheless, the surgical area cannot be directly observed, imaging methods are necessary to reveal whether the surgery has achieved the expected results. Cone-Beam Computed Tomography (CBCT) images are usually taken before surgery and at the completion of final pre-repair osseointegration and evaluate the effect of maxillary sinus lift by measuring the alveolar bone height in the bone graft area. However, there is no uniform and recognized method to accurately measure the alveolar bone height in the bone grafting area before and after maxillary sinus lift. Therefore, the authors propose a simple, accurate, and reproducible method for the measurement of alveolar bone height in maxillary sinus lift on CBCT, which will be an innovation. Methods: 30 implant cases (30 patients) were included in this study. The authors create a uniformed measurement surface in the CBCT axial interface to ensure consistency at the completion of final prerepair osseointegration and before surgery. Then changes in alveolar bone height in the bone grafting area before and after sinus lift were measured on CBCT coronal and arch planes. Finally, for the purpose of verification of repeatability, three dentists from our department were randomly selected to measure and record the above CBCT data at three different time points. Results: The data showed that in the CBCT measurements of the three dentists, neither the coronal plane nor the arch plane was statistically significant. (P > 0.05). Conclusion: This measurement method is simple, accurate and repeatable. It can be applied to measure alveolar bone height in the bone grafting area before and after maxillary sinus lift.

Objectives: This study aimed to clarify features of giant cavernous hemangioma (GCH) and liver hemangiomatosis, existing simultaneously on gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid (Gd-EOB-DTPA)-enhanced magnetic resonance imaging (MRI). Method: A total of 17 patients with reported hepatic hemangiomatosis between 2015 and 2017 were identified retrospectively. All our patients underwent pre-contrast MRI, triphasic (atrial, portal, venous) Gd-EOB-DTPA dynamic enhancement and hepatobiliary phase (20 minutes delayed). The location, size, morphology and signal characteristics on T1-weighted (T1WI) and T2-weighted images (T2WI), and Gd-EOB-DTPA-enhanced MRI of liver hemangiomatosis were evaluated. Results: Hemangiomatosis involved the liver adjacent to the edge of the GCH with no normal liver tissue found in 13 cases; in the other 4 patients, a small area of normal liver tissue separated GCH from hemangiomatosis was seen. On non-contrast MRI images, hemangionmatosis presented as numerous microcystic lesions, with low signal intensity on T1WI and high signal intensity on T2WI, compared with unaffected liver. After administration of Gd-EOB-DTPA, heterogeneous enhancement was presented in the arterial phase, during portal and venous phase imaging, becoming more homogeneous. 11 cases showed hypointensity in the hepatobiliary phase (6 cases with intratumor necrosis), and 6 cases showed hyper-intensity in the hepatobiliary phase with a remaining unfilled portion. Conclusion: Hemangiomatosis is extremely rare in the liver adjacent to a GCH. MRI is of great diagnostic and clinical value for this kind of tumor according to the configuration, size, signal, and style of enhancement, but the final diagnosis depends on pathology. Gd-EOB-DTPA-enhanced MRI may help in diagnosing hemangiomatosis coexistent with GCH.

Background: Electrical impedance tomography (EIT) can be used for continuous monitoring of pulmonary ventilation. However, no proper method has been developed for the separation of pulmonary ventilation and perfusion signals and the measurement of the associated ventilation/ perfusion (V/Q) ratio. Previously, various methods have been used to extract these components; however, these have not been able to effectively separate and validate cardiac- and pulmonary- related images. Aims: This study aims at validating and developing a novel method to separate cardiac- and pulmonary- related components based on the EIT simulation field of view and to simultaneously reconstruct the individual images instantly. Methods: Our approach combines the advantages of the principal component analysis (PCA) and processes that originally measure EIT data instead of handling a series of EIT images, thus introducing the empirical mode decomposition (EMD). The PCA template functions for cardiacrelated imaging and intrinsic mode functions (IMFs) of EMD for lung-related imaging are then adapted to input signals. Results: The proposed method enables the separation of cardiac- and lung-related components by adjusting the proportion of the key components related to lung imaging, which are the fourth component (PC4) and the first component (IMF1) in PCA- and EMD-based methods, respectively. The preliminary results on the application of the method to real human EIT data revealed the consistently better performance and optimal computation compared with previous methods. Conclusion: This study proposes a novel method for applying EIT to evaluate the best time of V/Q matching on the cardiovascular and respiratory systems; this aspect can be investigated in future research.

Background: There are numerous difficulties in using deep learning to automatically locate and identify diseases in chest X-rays (CXR). The most prevailing two are the lack of labeled data of disease locations and poor model transferability between different datasets. This study aims to tackle these problems. Methods: We built a new form of bounding box dataset and developed a two-stage model for disease localization and identification of CXRs based on deep learning. The dataset marks anomalous regions in CXRs but not the corresponding diseases, different from all previous datasets. The advantages of this design are reduced labor of annotation and fewer possible errors associated with image labeling. The two-stage model combines the robustness of the region proposal network, feature pyramid network, and multi-instance learning techniques. We trained and validated our model with the new bounding box dataset and the CheXpert dataset. Then, we tested its classification and localization performance on an external dataset, which is the official split test set of ChestX-ray14. Results: For classification result, the mean area under the receiver operating characteristic curve (AUC) metrics of our model on the CheXpert validation dataset was 0.912, which was 0.021, superior to the baseline model. The mean AUC of our model on an external testing set was 0.784, whereas the state-of-the-art model got 0.773. The localization results showed comparable performance to the stateof- the-art models. Conclusion: Our model exhibits a good transferability between datasets. The new bounding box dataset is proven to be useful and shows an alternative technique for compiling disease localization datasets.

Background: Isolated pituitary gland metastasis is an extremely rare event in renal cell carcinoma. We present a unique case of isolated pituitary metastasis of renal cell carcinoma and a systematic review of literature on it. Case Report: In this case, an abdominal ultrasound in an asymptomatic 51-year-old female patient showed a mass in her left kidney. Radical nephrectomy was performed and the tumor was diagnosed as a stage 1 clear cell carcinoma. Throughout the 3 months of the follow-up period, the patient started complaining of visual disturbances and headaches. A pituitary mass was found on brain magnetic resonance imaging and was suspected to be a macroadenoma. Surgical resection of the tumor was performed and the final pathological diagnosis was made as a pituitary metastasis of the renal cell carcinoma. After surgery, radiotherapy with sunitinib, a receptor tyrosine inhibitor, was performed. Conclusion: The clinical symptoms are usually related to the mass effect of the tumor and anterior pituitary involvement. Most of the cases mimic pituitary macroadenoma on MRI. The most preferred treatment combination is surgery and radiotherapy. We recommend adding sunitinib to this combination. This illustrative case and those found in a systematic review of the literature highlight the importance of histopathologic diagnosis and appropriate management since isolated pituitary metastasis is challenging to preoperative diagnosis.

Background: Optical coherence tomography (OCT) is a real-time three-dimensional tomography optical imaging technology that uses near-infrared waves to take cross-sectional pictures of the retina and other tissues. A few studies have reported the use of intraoperative OCT navigation for the removal of foreign bodies from the eyeball during surgery. The objective is to present a single case with a small foreign body (not embedded in the retina) treated with intraoperative OCT guided 25G micro-amount trajectory vitrectomy. Case Presentation: The examination of a 25-year-old man, who suffered from right eye pain, suggested the following: the visual acuity was 20/250, the intraocular pressure was 8 mmHg, a scleral penetrating wound was visible at 3 mm behind the limbus at 7 o' clock, and Tyn (+). The vitreous showed some flocculent turbidity, the retina was flat, and the foreign body was visible at 10 o' clock. On the day of admission, the patient underwent a micro-amount vitrectomy with the removal of the foreign body. The vitreous body affected by the foreign body was then removed through the original wound track by using intraoperative OCT navigation. Conclusion: The final follow-up showed the best-corrected vision of the right eye as 20/25 andno occurrence of complications. The intraoperative OCT-guided 25G micro-amount trajectory vitrectomy could be used as an accurate, useful, and safe method for foreign body extraction.

Introduction: Paragangliomas are tumors of neuroendocrine origin, may appear in different localizations, and are related to the autonomic nervous system. Paragangliomas are generally asymptomatic and may rarely appear with adrenergic symptoms, and clinical findings depend on the catecholamines they secrete. Extra-adrenal paragangliomas are mostly benign, like all paragangliomas. Malignancy criteria consist of local recurrence, metastasis after total resection, and presence of distant metastasis during primary diagnosis. Case Presentation: This report presents the case of a 31-year-old man with jugular paraganglioma, multiple skeletal metastases, and a long-segment tumor thrombus. Imaging procedures showed a continuous tumor thrombus extending from the posterior fossa to the right atrium and metastases in C2, T1, T6, T8, L5, and right humerus. Histopathological assessment of the metastasis in C2 identified malignant paraganglioma. Curative surgery was not an option for this patient, hence combined chemotherapy was given. Conclusion: In cases of malignant paraganglioma with multiple distant metastases, chemotherapy and radiotherapy are feasible treatment methods.

Background: Fabry disease (FD) is a rare X-linked multisystem lysosomal storage disease caused by partial or total deficiency of a-galactosidase A (GLA). A progressive involvement of the kidneys, heart, and brain arteries has been reported. Using the transcranial color-coded duplex Doppler (TCCD), we report the case of a Fabry disease (FD) patient with a reduction in the cerebrovascular reactivity of the basilar artery (BA). Methods: A 46-year-old male asymptomatic FD patient underwent ultrasound intracranial investigation. Case Presentation: We report the case of a 46-year-old man affected by asymptomatic FD, who presented to our observation for episodes of vertigo. Cerebral MRI and AngioMRI were found to be normal. There was no postural hypotension observed. Otolaryngology and cardiac examinations revealed no pathological condition. A TCCD showed normal cerebral vascular reactivity (CVR) in the bilateral middle cerebral arteries (MCA), breath-holding index (BHI) was 1.3 in the right MCA (RMCA) and 1.4 in left MCA (LMCA), and BHI in the basilar artery (BA) was reduced (BHI: 0,56). Conclusion: This case suggests an earlier alteration of CVR in the posterior cerebral circulation than in the anterior cerebral circulation in an asymptomatic FD patient. This alteration of CVR may be an earlier marker of FD diagnosis.