Current Medical Imaging - Volume 20, Issue 1, 2024

Millions of people have been infected with COVID-19, which has spread quickly worldwide since the start of 2020, resulting in numerous fatalities. Identification of infected individuals is essential to control the spread of the virus.

In this study, we propose a hybrid architecture that combines Convolutional Neural Networks (CNNs) with Recurrent Neural Networks (RNNs) and leverages transfer learning to enhance the accuracy of COVID-19 detection from X-ray images.

The proposed work utilizes 4 pre-trained CNN architectures, namely, InceptionnetV3, Densenet121, Inception-ResNet V2, and VGG19, to extract high-level features from the input X-ray images. These features are then fed into the second component, an RNN-based network, which captures the temporal dependencies within the extracted features. To evaluate the performance of the proposed architecture, a comprehensive dataset consisting of X-ray images from COVID-19 positive cases, non-COVID-19 pneumonia cases, and healthy individuals is used. Gradient class activation map (Grad-CAM) analysis has been applied to the obtained results to provide heat-map pictures specific to each class and coloured visualizations of the COVID-19-infected areas in CXR images.

: Experimental results demonstrate that the proposed hybrid CNN-RNN architecture achieves promising results in COVID-19 detection from X-ray images. The model exhibits high accuracy, precision, recall, area under the receiver operating characteristics (ROC) curve (AUC), and F1-score, outperforming other state-of-the-art methods.

The combination of CNNs and RNNs enables the model to effectively capture spatial and temporal information, leading to improved performance in COVID-19 detection. The proposed hybrid architecture with transfer learning from X-ray images provides a robust and efficient solution for COVID-19 detection. The model can potentially assist healthcare professionals in making accurate and timely diagnoses, thereby contributing to the global efforts to combat the COVID-19 pandemic. In the present work, VGG19-RNN architecture outperformed all other networks in terms of accuracy. The most effective training and validation accuracy for the VGG19-RNN architecture is 99% & 97.70%, respectively, and the loss was 0.02 & 0.09 at epoch 100.

Liesegang rings (LR) are concentric acellular lamellar structures, usually found in cystic and inflammatory tissues but can also be seen in neoplastic conditions. They have been mistakenly interpreted as various structures like psammomatous calcification, parasites, and algae. This study has aimed to systematically review and summarize the existence of LRs in both non-neoplastic and neoplastic conditions of the kidney. The systematic search in PUBMED, PUBMED CENTRAL, and EMBASE along with Google Scholar was performed by using Kidney, Liesegang Rings, or Liesegang structure or pseudo parasitic structure in combination with the Boolean operators ‘’and” as searching terms. Data was collected for demographic characteristics and histopathology diagnosis. The search function was limited to human subjects. Two reviewers independently performed the eligibility assessment and data extraction. Eligibility inclusion criteria were all publications in the English literature worldwide related to Liesegang rings in association with kidney’s non-neoplastic and neoplastic conditions, regardless of the years of publication. Also included were those cases whose full articles were unavailable, but the abstract was well-described, fulfilling our inclusive criteria. Eligibility exclusion criteria included LRs found elsewhere in the body organs apart from the kidney and availability of full text in a different language, non-human, and duplicate article/case.

After the exclusion of the articles as per the exclusion criteria, the total articles that fulfilled the inclusive criteria were reviewed. In addition, all the articles were further cross-referenced for additional articles. All published papers retrieved from this search were considered for this review. A total of 22 records (26 cases) were found with a diagnosis of LRs in the kidney to date. Some articles were published as case series. Accordingly, 26 patients were reported to have Liesegang rings associated with kidney neoplastic and non-neoplastic conditions, 12 were male and 14 were female. For one case the gender was not mentioned. LRs presented a higher frequency in individuals between 4^th and 5^th decades of life. No single case was reported in infants and younger children. Regarding predisposing factors for LRs, cystic fluid contents were the most common underlying condition.

In our practice, we encountered an unusual case of a 55-year-old female with a complaint of pain in the left upper quadrant of the abdomen. The ultrasound revealed nephrolithiasis and chronic kidney disease for which a nephrectomy was performed. On the histopathological examination, there was an incidental finding of Liesegang rings and a papillary adenoma along with features of chronic pyelonephritis. Our review will provide insight about LRs in different spectrums of kidney diseases.

This study represents the first available systematic review of the literature demonstrating LRs in the kidney. Although Liesegang rings have no great clinical significance, these, presence in both tissue and cytological specimens should be kept in mind while dealing with different lesions of the kidney as these are good mimickers of many organic and inorganic substances, parasites, and malignancies.

In some hospitals in remote areas, due to the lack of MRI scanners with high magnetic field intensity, only low-resolution MRI images can be obtained, hindering doctors from making correct diagnoses. In our study, high-resolution images can be obtained through low-resolution MRI images. Moreover, as our algorithm is a lightweight algorithm with a small number of parameters, it can be carried out in remote areas under the condition of the lack of computing resources. Moreover, our algorithm is of great clinical significance in providing references for doctors' diagnoses and treatment in remote areas.

We compared different super-resolution algorithms to obtain high-resolution MRI images, including SRGAN, SPSR, and LESRCNN. A global skip connection was applied to the original network of LESRCNN to use global semantic information to get better performance.

Experiments reported that our network improved SSMI by 0.8% and also achieved an obvious increase in PSNR, PI, and LPIPS compared to LESRCNN in our dataset. Similar to LESRCNN, our network has a very short running time, the small number of parameters, low time complexity, and low space complexity while ensuring high performance compared to SRGAN and SPSR. Five MRI doctors were invited for a subjective evaluation of our algorithm. All agreed on significant improvements and that our algorithm could be used clinically in remote areas and has great value.

The experimental results demonstrated the performance of our algorithm in super-resolution MRI image reconstruction. It allows us to obtain high-resolution images in the absence of high-field intensity MRI scanners, which has great clinical significance. The short running time, a small number of parameters, low time complexity, and low space complexity ensure that our network can be used in grassroots hospitals in remote areas that lack computing resources. We can reconstruct high-resolution MRI images in a short time, thus saving time for patients. Our algorithm is biased towards clinical and practical applications, and doctors have affirmed the clinical value of our algorithm.

The lack of knowledge of the relation of the maxillary sinus with the apexes of maxillary posterior teeth can lead to important complications during common dental procedures. This can be avoided using different imaging techniques, such as orthopantomography (OPG) and cone beam computed tomography (CBCT). The present study aims to compare the performance of OPG with CBCT in measuring the vertical distance of the apexes of posterior-superior teeth to the maxillary sinus.

This study corresponded to a cross-sectional study. OPGs and CBCT scans were obtained from the same individuals, and the qualitative and quantitative vertical distance of the apexes in relation to the maxillary sinus was categorized and measured in mm.

A total of 28 pairs of OPGs and CBCT scans from the same patients were obtained. About 381 roots were analysed, which included 89 upper first premolars, 51 upper second premolars, 115 upper first molars, and 126 upper second molars. Projection/protrusion was observed with more frequency in molars, specially 1º molars in both OPG (n= 75, 65.2%) and CBCT (n= 31, 27%); however, 106 more cases (27.9%) were classified as projected in the OPG compared to CBCT (p < 0.05). When comparing the performance of the OPG and CBTC for analysing all roots qualitatively, there was a 57.8% agreement between both techniques. This difference was statistically significant (p <0.0001). Statistically significant differences were also observed when comparing the millimetric differences.

This study showed that OPG is not an accurate technique to observe the relationship between the maxillary sinus and the apexes of the upper posterior teeth. In those cases where precision is required when performing dental procedures in this area, CBCT should be used. When not available, the clinicians should be aware of the limitations of the OPG and add other complementary techniques.

Gastric teratoma (GT) occurs as a rule in infancy and is an extremely unusual gastric tumor in adult patients.

In this paper, we present the clinical and imaging findings of a 56-year-old female patient with a GT. The patient's main symptoms were increasing abdominal discomfort and pain. After the physical examination, she underwent ultrasound (US) and computed tomography (CT), which showed a large mass at the posterior wall of the stomach, and a teratoma was initially considered. After surgery, pathology confirmed the diagnosis of GT. The patient recovered after surgery and was discharged in good health. To the best of our knowledge, this study is the first reported case of gastric teratoma in an adult woman in the literature.

Gastric teratoma of the adult period is a rare benign neoplasm that may have several complications; therefore, imaging is crucial for diagnosis and accurate treatment management. The aim of this study is to emphasize the value of US and CT in the diagnosis and treatment monitoring of mature gastric teratomas.

Brain tumors are predicted from Magnetic Resonance Imaging (MRI) and Computed Tomography (CT) scan images. In recent years, image processing-based automated tools are developed to predict tumor areas with less human interference. However, such automated tools are suffering from computational complexity and reduced accuracy in certain critical images. In the proposed work, an Ideal Shallow Neural Network (ISNN) is utilized to improve the prediction accuracy, and the computational complexity is reduced by implementing an Artificial Jellyfish Optimization (AJO) algorithm for minimizing the feature dimensionality.

The proposed method utilizes MRI images for the verification process as they are more informative than the CT scan image. The BRATS and the Kaggle datasets are used in this work and a Gabor filtering technique is used for noise reduction and a histogram equalization is used for enhancing the tumor boundary regions. The classification results observed from the AJO-ISNN are further forwarded towards the segmentation process and which uses the Centroid Weighted Segmentation (WCS) along with a Grasshopper Optimization Algorithm (GOA) for improving the segmentation over the boundary regions of the brain tumor.

The experimental result indicates a classification accuracy of 95.14% on the proposed AJO-ISNN model and AJO-ISNN is comparatively better than the Convolutional Neural Network (CNN) model accuracy of 85.41% and VGG 19 model accuracy of 93.75% while implemented with the AJO optimization model. Similarly, the Dice Similarity Coefficient of the proposed CWS-GOA also reaches 93.15% when performed with both BRATS and Kaggle datasets.

Apart from the accuracy attainments the proposed work classifies and segments the tumor region in around 65 seconds on average of 200 image verifications and that is comparatively better than the previous multi-cascaded CNN and the InceptionV3 models.

Hepatocellular carcinoma (HCC) is the leading type of liver cancer in adults, often resulting in fatal outcomes for those with cirrhosis. Dysplastic nodule (DN) is a liver nodule that is substantial in size, ranging from 1-2 cm. However, accurately distinguishing between DN and HCC on imaging has posed a challenge.

The aim of this study is to assess the usefulness of Gd-EOB-DTPA-enhanced MRI T1 mapping in distinguishing between DN and HCC.

This study analyzed 66 patients with confirmed HCC or DN who underwent Gd-EOB-DTPA-enhanced MRI T1 mapping before surgery or puncture at the Army Medical Center in China. The T1 values of each lesion were measured before and after Gd-EOB-DTPA administration, and various calculations were made, including absolute and percentage reduction in T1 value and coefficient of variation. The t-test was used to compare these values between the two groups, and the efficacy of T1 mapping values for differential diagnosis of HCC and DN was evaluated using the receiver operating characteristic curve (ROC).

The study found that T1pre, T1hp, ΔT1, ΔT1%, and CV in the HCC group were significantly higher than in the DN group (p < 0.01). The accuracy of T1hp, ΔT1, and CVT1-hp in identifying HCC from DN was high, with AUCs of 0.955, 0.910, and 0.932, respectively. ΔT1% also had some accuracy, with an AUC of 0.818.

Our results provide preliminary evidence that Gd-EOB-DTPA-enhanced MRI T1 mapping, can be a valuable tool in diagnosing and differentiating between HCC and DN.

Spectral-Domain Optical Coherence Tomography (SD-OCT) provides non-invasive, high-speed, high-resolution, three-dimensional cross-section imaging of the macula.

This study aimed to investigate the diagnostic value of the multimodal imaging technique of three-dimension (3D) optical coherence tomography (OCT) (3D-OCT) for the diagnosis and characterization of acute central serous chorioretinopathy (CSC).

In this prospective clinical study 3D-OCT examinations of 82 cases with acute CSC were performed on the macular area, and the image characteristics were analyzed. Our study included a total of 87 eyes from 82 cases of CSC patients, 67 males and 15 females (mean age ± standard deviation (SD): 42.89 ±7.80 years old; age range: 27 to 56 years old. The 3D-OCT images were evaluated for the presence of subretinal fluid, subretinal space, fluctuation of the internal limiting membrane (ILM), folds of retinal pigment epithelial (RPE), retinal pigment epithelium detachment (PED), and flat irregular PED. The foveal thickness was measured using the manual caliper of OCT software.

The OCT B-scan images showed 87 (100%) eyes had exudative retinal detachment (ERD), 38 (44%) had flat irregular PED, 36 (41%) had PED, 8 (9%) had subretinal turbidity structure, 2 (2%) had subretinal dot-like precipitates, 1 (1%) had focal choroidal excavation (FCE), and 1 (1%) eye had fluctuation of internal limiting membrane (FI). In the ILM-RPE thickness map, all eyes had a round or round like regular uniform domes. Fifty-seven (66%) domes were limited in the examination area and 30 (44%) domes were beyond the scope of this examination and only a partial section of the dome could be observed. In the en-face image, all eyes had a round or round-like black figure that corresponded with domes in the ILM-RPE thickness map. In RPE surface, 76 (87%) eyes had a shallow plate depression, 71(82%) had small focal uplift, and 1 (1%) eye had a focal concave feature.

In the OCT ILM-RPE thickness, en-face image, and RPE surface maps, acute CSC exhibited specific imaging characteristics that can be helpful for reliable diagnosis and differential diagnosis of CSC.

The characteristic imaging findings of breast cancer in young women are not yet fully understood. It causes a delay in diagnosis by mixing with benign findings.

To evaluate the relationship between the imaging and histopathological features of breast cancer in women aged under 40 years.

In our center, 537 suspicious lesions were detected in a total of 15,223 adult female patients under 40 years who were evaluated by breast ultrasonography (US). As a result of the mammographic, histopathological, and immunohistochemical analysis, 101 lesions meeting the study criteria were included in the sample.

The luminal subtypes of breast cancer mostly visualized as irregularly shaped spiculated lesions with calcification and architectural distortion mammography and presented as masses that were sometimes accompanied by increased echogenicity in the surrounding tissue on US. The human epidermal growth factor receptor 2 (HER2) enriched subtypes mostly had microlobulated or indistinct margins with heterogeneous echoes accompanied by high calcification on mammography. The triple-negative (TN) subtypes generally appeared as microlobulated lesions with angular or indistinct margins, hypo echogenicity, posterior enhancement or shadowing, and vascularization.

Some radiological features of breast cancer in young women were found to be associated with molecular subtypes similar to other age groups in the literature. However, unlike other age groups, the incidences of the HER2-enriched subtype presenting with only calcification, TN subtypes presenting with circumscribed masses, and calcification were found to be low among the young women in our study.

A large jejunal diverticulum has been reported as a possible cause of volvulus and acute mesenteric ischemia (AMI) in adults. A large diverticulum of the small bowel complicated with volvulus has been reported before in literature. However, imaging findings of a large diverticulum of the small bowel complicated with both volvulus and AMI on MDCT are rarely described and reported. In this study, we reported a case with a large diverticulum, volvulus, and AMI concurrently; these three imaging findings were reviewed and described on MDCT, and the relevant literature was briefly introduced.

We reported the case of a 69-year-old man who presented to our hospital with acute abdominal pain and vomiting. An emergent abdominal enhanced MDCT imaging was performed and demonstrated the volvulus secondary to a large diverticulum of the jejunum complicated with AMI. Here, a case was presented that highlighted unique imaging findings on MDCT, as well as a literature review.

A review of the literature revealed that a single jejunal diverticulum causing both volvulus and AMI is rare in adults. To our knowledge, a systemic description of their signs on MDCT in a case has not been reported yet.

Agenesis of the corpus callosum (ACC) is a rare hereditary nervous system defect present at birth. ACC is an uncommon condition that is unrepresentative in the general population because some cases do not present with any identifiable symptoms in the early stage.

We present a case of ACC in a two-month-old male patient who was diagnosed after birth. Although the initial brain ultrasound (US) showed dilation of the lateral ventricles and the absence of the corpus callosum, these findings were not fully confirmed. Therefore, magnetic resonance imaging (MRI) of the brain was conducted to confirm the complex diagnosis, and the examination revealed complete ACC. Diagnosing ACC in a neonate demonstrates the complexity of diagnosis through the clinical presentation, especially at an early age.

The clinical utility of neonatal US and MRI highlights the importance of an early diagnosis of ACC. MRI is more effective than the US in detecting this condition, and these imaging modalities provide the patient with an early diagnosis, which helps in treatment management.

We aimed to examine all-cause mortality risk in relation to the extent of non-obstructive coronary artery disease (CAD) by coronary computed tomography angiography (CTA) in Chinese middle-aged and older patients in a multicenter study with nine-year follow-up.

This was a retrospective, observational, multicentre study. The study population consisted of 3,240 consecutive middle-aged and older patients (age ≥ 40 years) with suspected CAD who underwent coronary CTA between June 2011 and December 2013 at three hospitals in Wuhan, China. Patients were grouped according to CAD extent for the final analysis: no CAD, 1-vessel non-obstructive CAD, 2-vessels non-obstructive CAD, and 3-vessels non-obstructive CAD. The primary endpoint was all-cause mortality. Kaplan-Meier method and Cox proportional hazards regression models were used for analysis.

A total of 2,522 patients were included in the present analysis. Of these, 188 (7.5%) deaths occurred during the median 9.0 years (interquartile range 8.6–9.4) of study follow-up. The annualized all-cause mortality rate was 0.54 (95% CI: 0.44–0.68), 0.91 (95% CI: 0.68–1.21), 1.44 (95% CI: 1.01–1.93), and 2.00 (95% CI: 1.46–2.69) for the no CAD, 1-vessel non-obstructive CAD, 2-vessels non-obstructive CAD, and 3-vessels non-obstructive CAD group, respectively. Kaplan–Meier survival curves showed a significant increase in the cumulative events associated with the extent of non-obstructive CAD (P < 0.001). In multivariate Cox regression, after adjustment for age and sex, the presence of 3-vessels non-obstructive CAD was a significant predictor of all-cause mortality (HR 1.60, 95% CI: 1.04–2.45, P = 0.032).

In this cohort of Chinese middle-aged and older patients undergoing coronary CTA, the presence and extent of non-obstructive CAD, compared to no CAD, were associated with a significantly greater nine-year risk of all-cause mortality. The present findings suggest the clinical importance of the stage of non-obstructive CAD and warrant investigation of the optimal risk stratification to improve outcomes among these patients.

The aims were to assess different branching patterns of segmental bronchi in the right superior lobe (RSL), as well as to investigate the anatomical diversity and sex-related variations of these branches in a large sample of the research population.

10,000 participants (5428 males, and 4,572 females, mean age 50+/-13.5 years [SD] years; age range: 3-91 years) who underwent multi-slice CT (MSCT) scans from September 2019 to December 2021 were retrospectively included. The data were applied to generate three-dimensional (3D) and virtual bronchoscopy (VB) simulations of a bronchial tree using the syngo.via post-processing workstation. Following that, the reconstructed images were interpreted to identify and categorize various bronchial patterns in the RSL. Cross-tabulation analysis and the Pearson chi-square test (χ2) were used to calculate the component ratios of bronchial branch types and determine their relevance between male and female groups.

Our results revealed mainly six types for the RSL bronchial tree, i.e., (B1, B2, B3, 60.70%); (B1+2, B3, 18.72%); (B2+3, B1, 6.68%); (B1+3, B2, 7.57%); (B1, B2, B3, B*, 3.19%); (B1a+B3, B1b+B2, 3.14%). There were significant sex-related differences in the proportion of bronchial branches in the RSL (P< 0.05).

The current study has validated the presence of segmental bronchial variations in the RSL. These findings may have significant implications for diagnosing symptomatic patients and performing particular procedures, including bronchoscopy, endotracheal intubation, and lung resection.

This study aimed to investigate the diagnosis of the external jugular venous aneurysm on color Doppler ultrasound and its relationship with pathological characteristics.

A retrospective analysis of 17 patients with external jugular venous aneurysm admitted to the Provincial Hospital Affiliated with Shandong First Medical University from May, 2010, to June, 2020, was performed. The color Doppler ultrasound characteristics of 17 patients with external jugular vein aneurysms were analyzed and summarized, which were then compared with postoperative pathological outcomes.

All 17 patients with external jugular venous aneurysms were presented with cystic structures adjacent to and communicated with the external jugular vein. Color Doppler flow imaging showed a bidirectional venous flow signal in the communication between the cystic structure and the external jugular vein. Among the 17 patients, ultrasound diagnosis showed true venous aneurysm due to degenerative changes in the venous wall in 8 cases, venous pseudoaneurysm in 4 cases, and external jugular venous aneurysm in 5 cases, and postoperative pathology indicated degenerative changes in the venous wall in all 17 patients.

Bidirectional blood flow at the communication between the cystic lesion and the external jugular vein on color Doppler ultrasound should not be the criterion for the diagnosis of external jugular venous pseudoaneurysm, which requires pathological support.