Distal coronary artery abnormalities in Kawasaki disease: experience on CT coronary angiography in 176 children.

OBJECTIVE: Precise evaluation of coronary artery abnormalities (CAAs) in Kawasaki disease (KD) is essential. The aim of this study is to determine role of CT coronary angiography (CTCA) for detection of CAAs in distal segments of coronary arteries in patients with KD. METHODS: CTCA findings of KD patients with distal coronary artery involvement were compared with those on transthoracic echocardiography (TTE) during the period 2013-21. RESULTS: Among 176 patients with KD who underwent CTCA (128-Slice Dual Source scanner), 23 (13.06%) had distal CAAs (right coronary-15/23; left anterior descending-14/23; left circumflex-4/23 patients). CTCA identified 60 aneurysms-37 proximal (36 fusiform; 1 saccular) and 23 distal (17 fusiform; 6 saccular); 11 patients with proximal aneurysms had distal contiguous extension; 9 patients showed non-contiguous aneurysms in both proximal and distal segments; 4 patients showed distal segment aneurysms in absence of proximal involvement of same coronary artery; 4 patients had isolated distal CAAs. On TTE, only 40 aneurysms could be identified. Further, distal CAAs could not be identified on TTE. CTCA also identified complications (thrombosis, mural calcification and stenosis) that were missed on TTE. CONCLUSIONS: CAAs can, at times, occur in distal segments in isolation and also in association with, or extension of, proximal CAAs. CTCA demonstrates CAAs in distal segments of coronary arteries, including branches, in a significant number of children with KD-these cannot be detected on TTE. CTCA may therefore be considered as a complimentary imaging modality in children with KD who have CAAs on TTE.

Multiparametric MR imaging with diffusion-weighted, intravoxel incoherent motion, diffusion tensor, and dynamic contrast-enhanced perfusion sequences to assess gallbladder wall thickening: a prospective study based on surgical histopathology.

OBJECTIVE: To investigate the diagnostic performance of a multiparametric magnetic resonance imaging (MRI) protocol comprising quantitative MRI (diffusion-weighted imaging (DWI), intravoxel incoherent motion (IVIM), diffusion tensor imaging (DTI), and dynamic contrast-enhanced (DCE) perfusion MRI) and conventional MRI in the characterization of gallbladder wall thickening (GWT). METHODS: This prospective study comprised consecutive adults with GWT who underwent multiparametric MRI between July 2020 and April 2022. Two radiologists evaluated the MRI independently. The final diagnosis was based on surgical histopathology. The association of MRI parameters with malignant GWT was evaluated. The area under the curve (AUC) for the quantitative MRI parameters and diagnostic performance of conventional, and multiparametric MRI were compared. The interobserver agreement between two radiologists was calculated. RESULTS: Thirty-five patients (mean age, 56 years, 23 females) with GWT (25 benign and ten malignant) were evaluated. The quantitative MRI parameters significantly associated with malignant GWT were apparent diffusion coefficient on DWI (p = 0.007) and mean diffusivity (MD) on DTI (p = 0.013), perfusion fraction (f) on IVIM (p = 0.033), time to peak enhancement (TTP, p = 0.008), and wash in rate (p = 0.049) on DCE-MRI. TTP had the highest AUC of 0.790, followed by MD (0.782) and f (0.742) (p = 0.213) for predicting malignant GWT. Multiparametric MRI had significantly higher sensitivity (90% vs. 80%, p = 0.045) than conventional MRI for diagnosing malignant GWT. The two radiologists' reading had substantial to near-perfect agreement (kappa = 0.639-1) and moderate to strong correlation (interclass correlation coefficient = 0.5-0.88). CONCLUSION: Multiparametric protocol incorporating advanced sequences improved the diagnostic performance of MRI for differentiating benign and malignant GWT. KEY POINTS: • Multiparametric MRI had 90% sensitivity and 88% specificity for diagnosing malignant GWT, compared to 80% sensitivity and 88% specificity for conventional CE-MRI. • Among the quantitative MRI parameters, TTP (perfusion-MRI) had the highest AUC of 0.790, followed by MD (0.782) and IVIM-f (0.742). • For most quantitative MRI parameters, there was moderate to strong agreement (ICC = 0.5-0.88).

Two-dimensional Shear Wave Elastography: Utility in Differentiating Gallbladder Cancer From Chronic Cholecystitis.

OBJECTIVE: To study the utility of 2D shear wave elastography (SWE) and ascertain cut-off values of shear wave elasticity (SWe) to differentiate benign and malignant thickening of the gallbladder wall. METHODS: This study was a prospective study of patients with symptomatic gallstone disease (GSD, n = 51) and gallbladder cancer (GBC, n = 46) and controls without any biliary disease (n = 46). All the participants underwent 2D USG and SWE of the gallbladder. Grey-scale ultrasound and SWE were done in the different regions in the gallbladder. RESULTS: The median age of the patients with GSD was 49 years (interquartile range [IQR]: 33-55), GBC was 55 years (IQR: 46-65), and controls was 37 years (IQR: 27-48.25). In patients with GBC, asymmetrical mural thickening was the predominant imaging pattern (n = 24, 52.2%). The mean SWe of the abnormal area in GBC (34.99 ± 17.77 kPa [n = 46]) was significantly higher than that of the uninvolved region (18.27 ± 8.12 kPa [n = 35]; P < .01). The mean SWe of the uninvolved region in GBC (18.27 ± 8.12 kPa [n = 35]) was also significantly higher (P < .01) than that of GSD (12.27 ± 4.13 kPa [n = 51]) and controls (10.52 ± 3.75 kPa [n = 46]). On ROC analysis, AUC of 0.927, at a cut-off of 20 kPa, sensitivity was 91.3%, specificity was 83.5%, positive likelihood ratio was 5.54, and negative likelihood ratio was 0.10 to diagnose GBC. CONCLUSION: The 2D SWE is a reliable adjunctive tool to grey-scale USG in differentiating the malignant from benign gallbladder wall and may help to pick up early malignancy in GSD.

MDCT evaluation of distal radius fractures and their association with carpal and distal ulnar fractures.

PURPOSE: The purpose of this study was to evaluate the characteristics of distal radius fractures (DRFs) in patients undergoing multi-detector computed tomography (MDCT) and their association with carpal and distal ulnar fractures. METHODS: This retrospective study analyzed 120 patients, who underwent MDCT for evaluation of DRFs. Two radiologists independently evaluated the data for various fracture characteristics and for associated carpal and distal ulnar fractures. RESULTS: Out of 120 DRFs, 74 were complete articular, 40 were partial articular and only 6 were extra-articular. Displacement was present in 99 fractures and intra-articular step off was present in 73 fractures. A total of 81 carpal bone fractures were identified in 46 (38.3%) patients, with more than one carpal bone fracture in 21 patients. Distal ulnar fractures were detected in 79 patients (65.8%), out of which 67 involved the ulnar styloid. DRFs with intra-articular step off were more frequently associated with carpal bone fracture (p value: 0.021), while displaced DRFs were more frequently associated with distal ulnar fracture (p value <0.001). Interobserver agreement for detection of carpal bone fractures (κ = 0.807) and distal ulnar fractures (κ = 0.923) was excellent. CONCLUSION: Majority of DRFs in patients referred for MDCT were complete articular with high incidence of displacement and intra-articular step off. Associated carpal bone and distal ulna fractures were not uncommon.

Contrast-enhanced ultrasound of solid pancreatic head lesions: a prospective study.

OBJECTIVE: To evaluate the role of contrast-enhanced ultrasound (CEUS) in the differential diagnosis of solid pancreatic head lesions (SPHL). METHODS: This prospective study comprised consecutive patients with SPHL who underwent CEUS evaluation of the pancreas. Findings recorded at CEUS were enhancement patterns (degree, completeness, centripetal enhancement, and percentage enhancement) and presence of central vessels. In addition, time to peak (TTP) and washout time (WT) were recorded. The final diagnosis was based on histopathology or cytology. Multivariate analysis was performed to identify parameters that were significantly associated with pancreatic ductal adenocarcinoma (PDAC). RESULTS: Ninety-eight patients (median age 53.8 years, 59 males) were evaluated. The final diagnosis was PDAC (n = 64, 65.3%), inflammatory mass (n = 16, 16.3%), neuroendocrine tumor (NET, n = 14, 14.3%), and other tumors (n = 4, 4.1%). Hypoenhancement, incomplete enhancement, and centripetal enhancement were significantly more common in PDAC than non-PDAC lesions (p = 0.001, p = 0.031, and p = 0.002, respectively). Central vessels were present in a significantly greater number of non-PDAC lesions (p = 0.0001). Hypoenhancement with < 30% enhancement at CEUS had sensitivity and specificity of 80.6% and 67.7%, respectively, for PDAC. There was no significant difference in the TTP and WT between PDAC and non - PDAC lesions. However, the WT was significantly shorter in PDAC compared to NET (p = 0.011). In multivariate analysis, lack of central vessels was significantly associated with a PDAC diagnosis. CONCLUSION: CEUS is a useful tool for the evaluation of SPHL. CEUS can be incorporated into the diagnostic algorithm to differentiate PDAC from non-PDAC lesions. KEY POINTS: • Hypoenhancement and incomplete enhancement at CEUS were significantly more common in PDAC than in non-PDAC. • Central vessels at CEUS were significantly associated with PDAC. • There was no difference in TTP and WT between PDAC and non-PDAC lesions.

Pulmonary Artery Pseudoaneurysm in COVID-19-Associated Pulmonary Mucormycosis: Case Series and Systematic Review of the Literature.

Literature on COVID-19-associated pulmonary mucormycosis (CAPM) is sparse. Pulmonary artery pseudoaneurysm (PAP) is an uncommon complication of pulmonary mucormycosis (PM), and rarely reported in CAPM. Herein, we report five cases of CAPM with PAP managed at our center and perform a systematic review of the literature. We diagnosed PM in those with clinico-radiological suspicion and confirmed it by microbiology or histopathology. We encountered five cases of CAPM with PAP (size ranged from 1 × 0.8 cm to ~ 4.9 × 4.8 cm). All subjects had diabetes and were aged 55-62 years (75% men). In two cases, COVID-19 and mucormycosis were diagnosed simultaneously, while in three others, COVID-19 preceded PM. One subject who underwent surgery survived, while all others died (80% mortality). From our systematic review, we identified one additional case of CAPM with PAP in a transplant recipient. CAPM with PAP is rare with high mortality. Early diagnosis and multimodality management are imperative to improve outcomes.

Role of Shear Wave Elastography of Synovium to Differentiate Rheumatoid and Tubercular Arthritis.

Background: Synovitis is the underlying pathology in various arthritis, and sometimes, it is difficult to differentiate various arthritis clinically or even by imaging. The purpose of our study was to use shear wave elastography (SWE) to evaluate rheumatoid arthritis (RA) and tubercular (TB) arthritis and to differentiate them using synovial stiffness. Methods: The prospective study was performed on Supersonic Imagine Aixplorer Ultrasound (USG) machine using a linear array probe SL10-2 (2-10 MHz). A total of 29 participants, 15 of RA (ACR/EULAR criteria) and 14 of proven TB arthritis were included. Region of interest of 1 mm was applied on the hypertrophied synovium and quantitative SWE data in form of elasticity (kPa) and velocity (m/s) were measured. Discrete categorical data were presented as n (%). Mean values were recorded along with standard deviation and the range of values. To find a maximal cutoff value of elasticity and velocity - receiver operating characteristic curve were plotted. Results: The mean elasticity and velocity values were 54.81 ± 10.6 kPa and 4.2 m/s ± 0.42 for RA and 37 ± 10 kPa and 3.4 ± 0.47 m/s for TB group. Significant difference (P < 0.001) was seen in elastic modulus values between rheumatoid and TB group with cutoff of 43.6 kPa to differentiate the two groups (sensitivity - 86.7% and specificity - 80%). Similar significant (P < 0.001) results were seen with velocity values, with cutoff of 3.76 m/s (sensitivity - 86.7% and specificity - 80%). Conclusion: SWE shows the potential to be a useful adjunct to gray scale and color Doppler USG in differentiating various arthritis on the basis of elastic properties of the synovium. Elastic modulus and velocity are useful SWE quantitative parameters for synovial evaluation and can differentiate RA and TB arthritis.

The role of diffusion-weighted imaging and dynamic contrast-enhanced magnetic resonance imaging for the diagnosis of diabetic foot osteomyelitis: a preliminary report.

Purpose: To assess the role of dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusionweighted imaging (DWI) in diagnosing diabetic foot osteomyelitis (DFO). Material and methods: Twenty-five participants with suspected osteomyelitis were included, who underwent MRI including DCE-MRI and DWI sequences. It was subsequently followed by bone biopsy and microbiological analysis (gold standard). The participants were divided into 2 groups based on biopsy results: DFO-positive or DFO-negative. The semi-quantitative DCE-MRI parameters (SI0, SImax, SIrel, wash-in rate [WIR], and type of curve) and apparent diffusion coefficient (ADC) values were subsequently compared between the 2 groups. Results: Out of the 25 cases, 19 were DFO-positive and 6 were DFO-negative on bone biopsy. The SI0, SImax, and WIR were significantly higher in DFO-positive cases (p-value 0.050, 0.023, and 0.004, respectively). No difference was seen in SIrel. 100% negative cases revealed type-I curve, and 94% of positive cases showed type-II curve. SI0 > 143.4 revealed a sensitivity of 94.7% and specificity of 83.3%. SImax had a sensitivity of 89.5% but lower specificity of 67.7% at a cut-off value of 408.35. The most significant difference was seen with WIR; p-value ~0.004. At the cut-off value of > 1.280, it had a specificity and sensitivity of 100% and 76%, respectively. Also, ADC values below 1.57 × 10-3 had a sensitivity of 88.2% and specificity of 80% for diagnosing DFO. Conclusions: DWI and DCE-MRI provide non-invasive sequences, which can help to increase the overall specificity and sensitivity of conventional MRI for the diagnosis of osteomyelitis, differentiating it from acute Charcot's arthropathy.

Percutaneous transthoracic embolisation for massive haemoptysis secondary to peripheral pulmonary artery pseudoaneurysms.

OBJECTIVE: Pulmonary artery pseudoaneurysms (PAPs) are rare, but important and treatable cause of massive haemoptysis. Minimal data exists on their interventional radiology management due to their rarity, especially direct percutaneous injection. Here, we report our experience of direct percutaneous management of such pseudoaneurysms. METHODS: Data of patients presenting to our department from January 2014 to November 2019 was retrospectively analysed, who presented with massive haemoptysis, and CT angiography positive for pulmonary artery pseudoaneurysms. Only patients treated with direct percutaneous intervention were included. Twelve patients who were managed endovascularly were excluded from the study. Observations were tabulated under age, sex, underlying pathology, lobe involved, number and size of the pseudoaneurysm, imaging guidance and embolising agent. Technical and clinical success and complications were then analysed. RESULTS: Twenty-nine pseudoaneurysms were treated in 27 patients with a mean age of 41.4 years. The most common underlying aetiology was tuberculosis (85.1%), with the most common location being bilateral upper lobes (31% each). CT guidance was the most frequently used imaging guidance (26/29). N-butyl cyanoacrylate (NBCA) glue mixture was used in 79.3% and reconstituted thrombin in the remaining 20.7% pseudoaneurysms. Complete technical and clinical success rates were 93.1% and 88.9% respectively. No major complications were seen except for development of significant pneumothorax in one patient. CONCLUSION: Pulmonary pseudoaneurysms are rare but fatal cause for massive haemoptysis. Interventional radiology management via direct percutaneous embolisation is a safe and minimally invasive treatment measure in selective patients, with successful outcomes and minimal complication and recurrence rates. KEY POINTS: • Pulmonary artery pseudoaneurysms are rare but important and treatable cause of massive haemoptysis. • This study shows the advantages of percutaneous management of these pseudoaneurysms as an alternate to endovascular embolisation, in case endovascular embolisation is not feasible or practical. • It is a safe and minimally invasive treatment, with technical success of 93.1% and clinical success of 88.9% in this study.

Larger bore percutaneous catheter in necrotic pancreatic fluid collection is associated with better outcomes.

OBJECTIVE: To evaluate the impact of initial catheter size on the clinical outcomes in acute pancreatitis (AP). METHODS: This retrospective study comprised consecutive patients with AP who underwent percutaneous catheter drainage (PCD) between January 2018 and May 2019. Three hundred fifteen consecutive patients underwent PCD during the study period. Based on the initial catheter size, patients were divided into group I (≤ 12 F) and group II (> 12 F). The differences in the clinical outcomes between the two groups, as well as multiple subgroups (based on the severity, timing of drainage, and presence of organ failure (OF)), were evaluated. RESULTS: One hundred forty-six patients (mean age, 41.2 years, 114 males) fulfilled the inclusion criteria. Ninety-nine (67.8%) patients had severe AP based on revised Atlanta classification. The mean pain to PCD was 22 days (range, 3-267 days). Mean length of hospitalization (LOH) was 27.9 ± 15.8 days. Necrosectomy was performed in 20.5% of patients, and mortality was 16.4%. Group I and II comprised 74 and 72 patients, respectively. There was no significant difference in baseline characteristics, except for a greater number of patients with OF in group II (p = 0.048). The intensive care unit stay was significantly shorter, and multiple readmissions were less frequent in group II (p = 0.037 and 0.013, respectively). Patients with severe AP and moderately severe AP in group II had significantly reduced rates of readmissions (p = 0.035) and significantly shorter LOH (p = 0.041), respectively. CONCLUSION: Large-sized catheters were associated with better clinical outcomes regardless of disease severity and other baseline disease characteristics. KEY POINTS: • Larger catheter size for initial PCD was associated with better clinical outcomes in AP. • The benefits were independent of the severity of AP, timing of PCD (ANC vs. WON) and presence of organ failure.

Overall survival and local recurrence following RFA, MWA, and cryoablation of very early and early HCC: a systematic review and Bayesian network meta-analysis.

OBJECTIVE: To compare overall survival (OS) and local recurrence (LR) following radiofrequency ablation (RFA), microwave ablation (MWA), and cryoablation (CA) for very early and early hepatocellular carcinoma (HCC). METHODS: This systematic review was performed according to the PRISMA guidelines. MEDLINE, Embase, and Cochrane databases were searched. Randomized controlled trials (RCTs) and observational studies were included. OS and LR at 1 year and 3 years were assessed. OS was reported as hazard ratio (HR) with 95% credible intervals (CrI) and LR as relative risk (RR) with 95% CrI, to summarize effect of each comparison. RESULTS: Nineteen studies (3043 patients), including six RCTs and 13 observational studies, met inclusion criteria. For OS at 1 year, as compared to RFA, CA had HR of 0.81 (95% CrI: 0.43-1.51), and MWA had HR of 1.01 (95% CrI: 0.71-1.43). For OS at 3 years, as compared to RFA, CA had HR of 0.90 (95% CrI: 0.48-1.64) and MWA had HR of 1.07 (95% CrI: 0.73-1.50). For LR at 1 year, CA and MWA had RR of 0.75 (95% CrI: 0.45-1.24) and 0.93 (95% CrI: 0.78-1.14), respectively, as compared to RFA. For LR at 3 years, CA and MWA had RR of 0.96 (0.74-1.23) and 0.98 (0.87-1.09), respectively, as compared to RFA. Overall, none of the comparisons was statistically significant. Age of patients and tumor size did not influence treatment effect. CONCLUSIONS: RFA, MWA, and CA are equally effective for locoregional treatment of very early and early HCC. KEY POINTS: • There is no significant difference in the OS and LR (at 1 year and 3 years) following ablation of very early and early HCC with RFA, MWA, and CA. • There was no effect of tumor size on the treatment efficacy. • More RCTs comparing CA with RFA and MWA should be performed.

Comparison of virtual computed tomography enteroscopy using carbon dioxide with small-bowel enteroclysis and capsule endoscopy in patients with small-bowel tuberculosis.

OBJECTIVE: Comparison of virtual CT enteroscopy (VCTE) using carbon dioxide with small-bowel enteroclysis (SBE) and capsule endoscopy (CE) in small-bowel tuberculosis (SBTB). METHODS: This prospective study comprised consecutive patients suspected to have SBTB. VCTE and SBE were performed on the same day and evaluated by independent radiologists. CE was performed within 2 weeks. VCTE was performed following insufflation of carbon dioxide via catheters in the jejunum and anorectum. A contrast-enhanced CT was followed by a delayed non-contrast CT. Image processing was done using virtual colonoscopy software. Findings on VCTE, SBE, and CE were compared. The final diagnosis of SBTB was based on either histopathological or cytological findings, response to antitubercular treatment, or a combination of these. RESULTS: Of the 55 patients in whom VCTE was performed, complete data was available in 52 patients. A final diagnosis of SBTB was established in 37 patients. All patients had VCTE and SBE. CE was performed in 34 patients. Adequate luminal distension was achieved in all patients with SBE and 35 patients with VCTE. SBE showed more strictures in jejunum (10.8%) and ileum (75.7%) compared with VCTE (jejunum, 8.1%, and ileum, 64.9%) and CE (jejunum, 5.9%, and ileum, 61.8%). However, difference was not statistically significant. VCTE revealed a greater length of strictures in both the jejunum and ileum compared with SBE and CE. CONCLUSION: VCTE allows adequate evaluation of the bowel in most patients with SBTB. It allows detection of greater length of abnormality in jejunum and ileum compared with SBE and CE. KEY POINTS: • The use of VCTE using CO2 bowel insufflation in patients with SBTB should be considered. • VCTE allows detection of a greater length of abnormality in the jejunum and ileum.

Computed tomography chest in COVID-19: When & why?

Computed tomography (CT) of the chest plays an important role in the diagnosis and management of coronavirus disease 2019 (COVID-19), but it should not be used indiscriminately. This review provides indications of CT chest in COVID-19 suspect, positive and recovered patients based on the current scientific evidence and our personal experience. CT chest is not indicated as a routine screening modality due to its poor sensitivity and specificity. However, it is useful in a small subset of COVID-19 suspects who test negative on reverse transcription-polymerase chain reaction (RT-PCR) with normal/indeterminate chest X-ray (CXR) but have moderate-to-severe respiratory symptoms and high index of clinical suspicion. CT chest is not indicated in every RT-PCR-positive patient and should be done only in specific clinical scenarios, where it is expected to significantly contribute in the clinical management such as COVID-19 patients showing unexplained clinical deterioration and/or where other concurrent lung pathology or pulmonary thromboembolism needs exclusion. Serial CXR and point-of-care ultrasound are usually sufficient to evaluate the progression of COVID-19 pneumonia. CT chest is also indicated in COVID-19-positive patients with associated co-morbidities (age >65 yr, diabetes, hypertension, obesity, cardiovascular disease, chronic respiratory disease, immune-compromise, etc.) who, despite having mild symptoms and normal/indeterminate CXR, record oxygen saturation of <93 per cent at rest while breathing room air or de-saturate on six-minute walk test. Finally, CT chest plays a crucial role to rule out lung fibrosis in patients recovered from COVID-19 infection who present with hypoxia/impaired lung function on follow up. In conclusion, though CT chest is an indispensable diagnostic tool in COVID-19, it should be used judiciously and only when specifically indicated.

Interventional radiology management of extremity pseudoaneurysms: a pictorial essay.

Pseudoaneurysms are vascular abnormalities caused by a damaging force on an arterial wall, resulting in a persistent extravasation of blood into the surrounding tissue, which can be the result of infection, inflammation, trauma or any iatrogenic procedure. The incidence of extremity artery pseudoaneurysms is rising because of increased number of endovascular procedures. As a number of complications are associated with these false aneurysms, it is important to know the treatment modalities available. Ultrasound is the most common method of diagnosing extremity pseudoaneurysm because of their superficial location. Computed tomographic angiography is the next investigation of choice as it has three-dimensional capability and can help evaluate the vascular bed. Digital subtraction angiography is rarely used for diagnosis alone, and is used only when a therapeutic procedure is planned. Treatment of these pseudoaneurysms has shifted from open surgical procedures to minimally invasive treatment in recent years. The different techniques for tackling these lesions include ultrasound-guided compression, percutaneous thrombin or glue embolisation and endovascular coil or stent graft placement. In this pictorial essay, we review the different treatment modalities so that an interventional radiologist is aware of all the treatments he can offer when confronted with these lesions.

Evaluating Lung Changes in Long COVID: Ultra-Low-Dose vs. Standard-Dose CT Chest.

Background: Frequent chest CTs within a short period during follow-up of long COVID patients may increase the risk of radiation-related health effects in the exposed individuals. We aimed to assess the image quality and diagnostic accuracy of ultra-low-dose CT (ULDCT) chest compared to standard-dose CT (SDCT) in detecting lung abnormalities associated with long COVID. Methods: In this prospective study, 100 long COVID patients with respiratory dysfunction underwent SDCT and ULDCT chest that were compared in terms of objective (signal-to-noise ratio, SNR) and subjective image quality (image graininess, sharpness, artifacts, and diagnostic accuracy along with the European guidelines on image quality criteria for CT chest), detection of imaging patterns of long COVID, CT severity score, and effective radiation dose. Additionally, the diagnostic performance of ULDCT was compared among obese (BMI≥30 kg/m2) and non-obese (BMI<30 kg/m2) subjects. Results: The mean age of study participants was 53 ± 12.9 years, and 68% were male. The mean SNR was 31.4 ± 5.5 and 11.3 ± 4.6 for SDCT and ULDCT respectively (p< 0.0001). Common findings seen on SDCT included ground-glass opacities (GGOs, 77%), septal thickening/reticulations (67%), atelectatic/parenchymal bands (63%) and nodules (26%). ULDCT provided sharp images, with no/minimal graininess, and high diagnostic confidence in 81%, 82% and 80% of the cases respectively. The sensitivity of ULDCT for various patterns of long COVID was 72.7% (GGOs), 71.6% (interlobular septal thickening/reticulations), 100% (consolidation), 81% (atelectatic/parenchymal bands) and 76.9% (nodules). ULDCT scans in non-obese subjects exhibited a significantly higher sensitivity (88% vs. 60.3%, p < 0.0001) and diagnostic accuracy (97.7% vs. 84.9%, p < 0.0001) compared to obese subjects. ULDCT showed very strong correlation with SDCT in terms of CT severity score (r = 0.996, p < 0.0001). The mean effective radiation dose with ULDCT was 0.25 ± 0.02 mSv with net radiation dose reduction of 94.8% ± 1.7% (p < 0.0001) when compared to SDCT (5.5 ± 1.96 mSv). Conclusion: ULDCT scans achieved comparable diagnostic accuracy to SDCT for detecting long COVID lung abnormalities in non-obese patients, while significantly reducing radiation exposure.

Chest CT Findings at Six Months Following COVID-19 ARDS - Correlation With the mMRC Dyspnea Scale and Pulmonary Function Tests.

Background: Many survivors of severe COVID-19 pneumonia experience lingering respiratory issues. There is limited research on follow-up chest imaging findings in patients with COVID-19 ARDS, particularly in relation to their mMRC dyspnea scores and pulmonary function tests (PFTs). This study addresses this gap by investigating the clinical characteristics, mMRC dyspnea scores, PFTs, and chest CT findings of COVID-19 ARDS patients at the 6 months post-recovery. By analyzing these variables together, we aim to gain a better understanding of the long-term health consequences of COVID-19 ARDS. Methods: This prospective observational study included 56 subjects with COVID-19 ARDS with dyspnea at the six-month follow-up visits. These patients were evaluated by chest CT, mMRC dyspnea scale, and PFT. The CT severity score was calculated individually for each of the four major imaging findings - ground glass opacities (GGOs), parenchymal/atelectatic bands, reticulations/septal thickening, and consolidation - using a modified CT severity scoring system. Statistics were carried out to find any association between individual CT chest findings and the mMRC dyspnea scale and forced vital capacity (FVC). p values < 0.05 were considered statistically significant. Results: Our study population had a mean age of 55.86 ± 9.60 years, with 44 (78.6%) being men. Grades 1, 2, 3, and 4 on the mMRC dyspnea scale were seen in 57.1%, 30.4%, 10.7%, and 1.8% of patients respectively. Common CT findings observed were GGOs (94.6%), reticulations/septal thickening (96.4%), parenchymal/atelectatic bands (92.8%), and consolidation (14.3%). The mean modified CT severity scores for GGOs, reticulations/septal thickening, parenchymal/atelectatic bands, and consolidation were 10.32 ± 5.51 (range: 0-21), 7.66 ± 4.33 (range: 0-19), 4.77 ± 3.03 (range: 0-14) and 0.29 ± 0.91 (range 0-5) respectively. Reticulations/septal thickening (p = 0.0129) and parenchymal/atelectatic bands (p = 0.0453) were associated with an increased mMRC dyspnea scale. Parenchymal/atelectatic bands were also associated with abnormal FVC (<80%) (p = 0.0233). Conclusion: Six-month follow-up chest CTs of COVID-19 ARDS survivors with persistent respiratory problems showed a statistically significant relationship between increased mMRC dyspnea score and imaging patterns of reticulations/septal thickening and parenchymal/atelectatic bands; while parenchymal/atelectatic bands also showed a statistically significant correlation with reduced FVC.

Role of Computed Tomography Perfusion in Patients with Liver Cirrhosis and Hepatocellular Carcinoma.

Background: There is a lack of data on computed tomography (CT) perfusion parameters in patients with cirrhosis and the vascular changes that occur with increasing severity of cirrhosis, as well as changes that can occur in the remote/background liver parenchyma when hepatocellular carcinoma (HCC) develops. This study aimed to evaluate the association between CT perfusion parameters in the background liver parenchyma in cirrhotic patients with and without HCC. Methods: This prospective study comprised consecutive patients with cirrhosis with or without HCC. A CT perfusion scan of the whole liver was done on a 128-detector row CT scanner in the four-dimensional spiral mode. Arterial liver perfusion (ALP), portal venous perfusion (PVP), hepatic perfusion index (HPI), blood flow (BF), blood volume (BV), and time to peak (TTP) were assessed. The perfusion parameters of the background liver parenchyma (bALP, bPVP, bHPI, bBF, bBV, and bTTP) were compared between the patients with cirrhosis (group I) and cirrhosis with HCC (group II). Perfusion parameters were also compared between the background liver parenchyma and the HCC in group II. Results: Of the 93 patients evaluated during the study period, 60 patients (30 in group I and 30 in group II, mean age, 54.5 years, 53 men) were included in the analysis. Among the perfusion parameters in the background parenchyma, bPVP was lower and bHPI was higher in group II, suggesting increased hepatic arterial perfusion of even the remote background liver parenchyma in patients with HCC (P = 0.001 and P = 0.01, respectively). Perfusion parameters were significantly altered with increasing severity of cirrhosis (based on Child-Pugh class) both within and between groups. Additionally, there were significant differences in all the perfusion parameters between HCC and the background cirrhotic liver. Conclusion: HPI and PVP of background liver parenchyma were significantly different in cirrhosis with and without HCC and also showed a worsening trend with increasing grades of cirrhosis.

Proposal for a new morphological "combined type" of gallbladder cancer: description of radiopathological characteristics and comparison with other morphological types.

OBJECTIVE: To describe the radiopathological characteristics of a new morphological "combined type" of gallbladder cancer (GBC) and compare it with the mass replacing gallbladder and thickening types of GBC. MATERIALS AND METHODS: The imaging and pathological details of consecutive patients with GBC between August 2020 and December 2022 were retrospectively reviewed. Two radiologists reviewed computed tomography/magnetic resonance imaging in consensus for the morphological type of GBC. The radiologists classified GBC as mass replacing gallbladder, wall thickening, and combined type. The combined type was defined as a mass arising from the thickened wall of an adequately distended gallbladder that extended exophytically into the adjacent liver parenchyma. The presence of calculi, site, and size of lesion, biliary/portal vein involvement, liver, lymph node, and omental metastases was compared among the various types. The pathological characteristics were also compared. RESULTS: Of the 481 patients (median age 55 years, 63.2% females) included in the study, mass replacing gallbladder, wall thickening, and combined-type GBC were seen in 42.8% (206/481), 40.5% (195/481), and 16.6% (80/481) of patients, respectively. In the combined type of GBC, biliary/portal vein involvement was seen in 63.7% (51/80) and 7.5% (6/80) of patients. Liver, lymph node, and omental metastases were seen in 67.5% (54/80), 40% (32/80), and 41.2% (33/80) patients, respectively. Liver metastases were significantly more common in the combined type (p = 0.002). There were no significant differences in pathological characteristics among the various types. CONCLUSION: Combined-type GBC is less common than the mass replacing gallbladder and thickening types and is associated with a higher risk of liver metastases.

Contrast Enhanced CT Versus MRI for Accurate Diagnosis of Wall-thickening Type Gallbladder Cancer.

Introduction: Diagnosis of wall-thickening type gallbladder cancer (GBC) is challenging. Computed tomography (CT) and magnetic resonance imaging (MRI) are commonly utilized to evaluate gallbladder wall thickening. However, there is a lack of data comparing the performance of CT and MRI for the detection of wall-thickening type GBC. Aim: We aim to compare the diagnostic accuracy of CT and MRI in diagnosis of wall-thickening type GBC. Materials and methods: This prospective study comprised consecutive patients suspected of wall-thickening type GBC who underwent preoperative contrast-enhanced CT and MRI. The final diagnosis was based on the histopathology of the resected gallbladder lesion. Two radiologists independently reviewed the characteristics of gallbladder wall thickening at CT and MRI. The association of CT and MRI findings with histological diagnosis and the interobserver agreement of CT and MRI findings were assessed. Results: Thirty-three patients (malignancy, 13 and benign, 20) were included. None of the CT findings were significantly associated with GBC. However, at MRI, heterogeneous enhancement, indistinct interface with the liver, and diffusion restriction were significantly associated with malignancy (P = 0.006, <0.001, and 0.005, respectively), and intramural cysts were significantly associated with benign lesions (P = 0.012). For all MRI findings, the interobserver agreement was substantial to perfect (kappa = 0.697-1.000). At CT, the interobserver agreement was substantial to perfect (k = 0.631-1.000). Conclusion: These findings suggest that MRI may be preferred over CT in patients with suspected wall thickening type GBC. However, larger multicenter studies must confirm our findings.

Deep-learning enabled ultrasound based detection of gallbladder cancer in northern India: a prospective diagnostic study.

Background: Gallbladder cancer (GBC) is highly aggressive. Diagnosis of GBC is challenging as benign gallbladder lesions can have similar imaging features. We aim to develop and validate a deep learning (DL) model for the automatic detection of GBC at abdominal ultrasound (US) and compare its diagnostic performance with that of radiologists. Methods: In this prospective study, a multiscale, second-order pooling-based DL classifier model was trained (training and validation cohorts) using the US data of patients with gallbladder lesions acquired between August 2019 and June 2021 at the Postgraduate Institute of Medical Education and research, a tertiary care hospital in North India. The performance of the DL model to detect GBC was evaluated in a temporally independent test cohort (July 2021-September 2022) and was compared with that of two radiologists. Findings: The study included 233 patients in the training set (mean age, 48 ± (2SD) 23 years; 142 women), 59 patients in the validation set (mean age, 51.4 ± 19.2 years; 38 women), and 273 patients in the test set (mean age, 50.4 ± 22.1 years; 177 women). In the test set, the DL model had sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) of 92.3% (95% CI, 88.1-95.6), 74.4% (95% CI, 65.3-79.9), and 0.887 (95% CI, 0.844-0.930), respectively for detecting GBC which was comparable to both the radiologists. The DL-based approach showed high sensitivity (89.8-93%) and AUC (0.810-0.890) for detecting GBC in the presence of stones, contracted gallbladders, lesion size <10 mm, and neck lesions, which was comparable to both the radiologists (p = 0.052-0.738 for sensitivity and p = 0.061-0.745 for AUC). The sensitivity for DL-based detection of mural thickening type of GBC was significantly greater than one of the radiologists (87.8% vs. 72.8%, p = 0.012), despite a reduced specificity. Interpretation: The DL-based approach demonstrated diagnostic performance comparable to experienced radiologists in detecting GBC using US. However, multicentre studies are warranted to explore the potential of DL-based diagnosis of GBC fully. Funding: None.