Gastrointestinal Imaging Findings in the Era of COVID-19: A Pictorial Review.

The potentially fatal COVID-19 pandemic has been associated with a largespectrum of clinical presentations. Beyond the classical pulmonary manifestations, gastrointestinal tract-related symptoms suchas nausea, diarrhea, abdominal distention and pain have been observed in patients, as a consequence of the binding of SARS-CoV-19 to Angiotensin-converting Enzyme 2 (ACE2) receptors in the gastrointestinal (GI) tract. The early recognition ofspecific imaging features, including hepatobiliary involvement, pancreatic involvement, development of solid organ infarcts, ischemic bowel changes and vascular occlusion, plays a key role through the course of the disease. Also, suspicious symptoms, especially in critically ill patients with clinical and biochemical markers of hypovolemia, necessitate timely imaging for bleeding complications. The aim of this pictorial review is to illustrate the spectrum of the GIimaging findings in patients with COVID-19. Awareness of diagnostic imaging hallmarks is crucial to optimize the management of these patients.

In vivo estimation of normal amygdala volume from structural MRI scans with anatomical-based segmentation.

PURPOSE: Literature includes a number of studies using structural MRI (sMRI) to determine the volume of the amygdala, which is modified in various pathologic conditions. The reported values vary widely mainly because of different anatomical approaches to the complex. This study aims at estimating of the normal amygdala volume from sMRI scans using a recent anatomical definition described in a study based on post-mortem material. METHODS: The amygdala volume has been calculated in 106 healthy subjects, using sMRI and anatomical-based segmentation. The resulting volumes have been analyzed for differences related to hemisphere, sex, and age. RESULTS: The mean amygdalar volume was estimated at 1.42 cm3. The mean right amygdala volume has been found larger than the left, but the difference for the raw values was within the limits of the method error. No intersexual differences or age-related alterations have been observed. CONCLUSION: The study provides a method for determining the boundaries of the amygdala in sMRI scans based on recent anatomical considerations and an estimation of the mean normal amygdala volume from a quite large number of scans for future use in comparative studies.

Treating peritoneal mesothelioma with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy. A case series and review of the literature.

BACKGROUND: Encouraging results on survival of patients with malignant peritoneal mesothelioma have been shown with the use of cytoreductive surgery and perioperative intraperitoneal chemotherapy. This study explores the impact of aggressive surgical treatment on overall survival of peritoneal mesothelioma. METHODS: This is a retrospective analysis of prospectively collected clinical data of all patients with diagnosis of malignant peritoneal mesothelioma treated in a designated referral centre in Greece. All patients were offered cytoreductive surgery and intraperitoneal chemotherapy. Patient's characteristics, operative reports, pathology reports, and discharge summaries were stored in an electronic database and later reviewed and analysed. RESULTS: Cytoreduction for peritoneal mesothelioma was performed on 20 patients (15 men and 5 women) with a mean age of 59.4 years (SD 16.1). Mean peritoneal cancer index was 16.1 (SD 10.4) and the median completeness of cytoreduction score was 2 (range 1-2). Mean overall survival was 46.8 months (SE 4.03) with a mean of 21.4 and median of 18 months of follow-up. Disease-specific survival was 100% for the observed period. Univariate analysis showed the completeness of cytoreduction as the only possible predictor of survival. A median of 10 (range 4-14) peritonectomy procedures were performed per patient. Median hospital stay was 14 (range 10-57 days). Grade III and IV complications occurred post-operatively in 5 patients (25%). Two patients died in the post-operative period of pulmonary embolism and myocardial infarction. CONCLUSION: Cytoreductive surgery with HIPEC has proved the most effective treatment even when taking account of the cost of significant morbidity.

CT-Enteroclysis in the preoperative assessment of the small-bowel involvement in patients with peritoneal carcinomatosis, candidates for cytoreductive surgery and hyperthermic intraperitoneal chemotherapy.

PURPOSE: To assess the performance of CT-Enteroclysis (CTE) in the preoperative evaluation of the small bowel (SB) involvement in patients with peritoneal carcinomatosis (PC), candidates for cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemotherapy (HIPEC). MATERIAL AND METHODS: In this prospective study, 48 consecutive patients (37 women, 11 men, mean age: 57.02 years) with PC of different primaries, eligible for cytoreductive surgery and HIPEC underwent CTE before surgery. Lesions were gathered according to their location (SB wall or mesentery), distribution (jejunum/ileum, proximal/distal) and lesion size (LS, where LS0 is the absence of disease, LS1 < 1 cm, LS < 1-5 cm, and LS3 > 5 cm in maximal diameter). The preoperative CTE classification was correlated with surgical scoring of PC in the SB. RESULTS: CTE was found to have sensitivity 92%, specificity 96%, PPV 97%, NPV 91%, in assessing PC in the SB/mesentery. CTE exhibited "excellent" agreement with surgical classification of disease extent (overall kappa-weighted coefficient of agreement (κ (w)) was 0.962). Patients (n = 6) found inoperable at surgery manifested extensive plaque-like cover of the SB wall/mesentery on CTE. CONCLUSIONS: CTE may be considered a reliable imaging technique for the preoperative evaluation of the extent and distribution of PC in the SB/mesentery in order to assist surgical planning or to prevent unnecessary surgery.

Multiparametric ultrasound for upper extremity dialysis access evaluation.

The evolution of ultrasound (US) techniques has greatly improved the evaluation of many parameters in dialysis vascular access, which is typically achieved through an arteriovenous fistula (AVF) or graft (AVG). These techniques include grayscale B-mode, color Doppler, power Doppler, spectral Doppler, non-Doppler US flow imaging techniques, contrast-enhanced US, and elastography. In conjunction with a patient's medical history and physical examination, US provides crucial information about the native vascular bed prior to the surgical creation of an arteriovenous anastomosis. It also tracks the maturation progress of the newly created AVF or AVG and aids in diagnosing potential complications of the vascular access. These complications include thrombosis, steal syndrome, aneurysms, pseudoaneurysms, hematomas, infection, ischemic neuropathy, exacerbation of preexisting congestive heart failure, and stenosis.

Perfusion parameters analysis of the vertebral bone marrow in patients with Ph¹â» chronic myeloproliferative neoplasms (Ph(neg) MPN): a dynamic contrast-enhanced MRI (DCE-MRI) study.

PURPOSE: To evaluate perfusion parameters of the vertebral bone marrow in patients with Philadelphia negative chronic myeloproliferative neoplasms (Ph(neg) MPN) using dynamic contrast-enhanced MRI (DCE-MRI). MATERIALS AND METHODS: The study enrolled 24 patients with Ph(neg) MPN: 12 patients with myelofibrosis (Group A), 6 with essential thrombocythemia (ET), and 6 with polycythemia vera (PV) (Group B) who underwent DCE-MRI of the lumbosacral spine. Twelve normal individuals served as control group (Group C). Wash-in (WIN), wash-out (WOUT), maximum contrast-enhancement (CE max), time-to-peak (TTPK), time-to-maximum slope (TMSP), and the WIN/TMSP ratio (WTSP) were calculated. RESULTS: WIN, CE(max) , and WTSP parameters were higher in Group A than in Group C (P < 0.05). These parameters were significant (P < 0.0001) in discriminating patients with myelofibrosis from normal individuals with sensitivities 74.14%, 87.93%, 74.14%, and specificities 91.07%, 83.93%, 91.07%, respectively. WIN, WOUT, CE(max) , and WTSP parameters were higher in Group A than in Group B (P < 0.05). Group B exhibited no differences in perfusion parameters as compared with Group C with the exception of WOUT. CONCLUSION: Patients with myelofibrosis exhibited increased perfusion parameters in vertebral bone marrow, which could be consisted with increased vascularity, probably related to neoangiogenesis as opposed to ET or PV patients showing no increased perfusion. DCE-MRI may be of value in discriminating subgroups of Ph(neg) MPN patients and in indicating those progressing to myelofibrosis.

Basal ganglia hyperintensity on T1-weighted MRI in Rendu-Osler-Weber disease.

The purpose of this study was to evaluate possible central nervous system (CNS) involvement in Rendu-Osler-Weber (ROW) disease in magnetic resonance imaging (MRI). Three patients with symptomatic ROW disease underwent brain MRI. Brain MRI depicted in all three of them increased signal intensity on T1-weighted images involving the globus pallidus and cerebral crura bilaterally. Laboratory studies of the two men showed iron deficiency anemia, while all three of them had normal liver function tests and increased manganese blood concentration. Gastroscopy and colonoscopy revealed a gastric and a cecal arteriovenous malformation (AVM) in the first one, while pulmonary and hepatic computed tomography (CT) angiography did not detect any intrahepatic shunts. Liver ultrasound in the second one revealed dilatation of intrahepatic artery branches consistent with intrahepatic shunts, while it was normal in the third patient. Chest radiographs were normal in all three patients. Pallidal T1 hyperintensity on T1-weighted imaging may be a biomarker of manganese overload in ROW disease.

Ultrasound Elastography: another piece in the puzzle of carotid plaque vulnerability?

Recent literature has shown that various carotid plaque features, other than stenosis, contribute to plaque vulnerability. Features such as surface morphology and plaque composition with distinct components (e.g. intraplaque hemorrhage, lipid core) have been associated with the increased risk of future cerebrovascular events. Ultrasonography constitutes the first line modality for the assessment of carotid disease and has traditionally been used to grade stenosis with high accuracy. Recenttechnological advances such as contrast-enhanced ultrasound and elastography increased the diagnostic yield of ultrasound in assessing the morphology of carotid plaques. The purpose of this review is to present the available literature on ultrasound elastography of the atherosclerotic carotid. Strain and shear wave elastography allow for the characterization of plaque components, thus indicating its nature and importantly, the plaque's vulnerability. Shear wave elastography indices appear morerobust than Strain indices. Overall, elastography is a feasible method to distinguish vulnerable carotid plaques. There is, however, a need for larger and longer prospective controlled clinical studies in order to validate elastography as an imaging modality used for the detection of unstable carotid plaques.

"Pseudowashout" artifact on liver haemangioma on CEUS: what to expect and how to avoid!

Not applicable.

Current Imaging Diagnosis of Hepatocellular Carcinoma.

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer related death worldwide. Radiology has traditionally played a central role in HCC management, ranging from screening of high-risk patients to non-invasive diagnosis, as well as the evaluation of treatment response and post-treatment follow-up. From liver ultrasonography with or without contrast to dynamic multiple phased CT and dynamic MRI with diffusion protocols, great progress has been achieved in the last decade. Throughout the last few years, pathological, biological, genetic, and immune-chemical analyses have revealed several tumoral subtypes with diverse biological behavior, highlighting the need for the re-evaluation of established radiological methods. Considering these changes, novel methods that provide functional and quantitative parameters in addition to morphological information are increasingly incorporated into modern diagnostic protocols for HCC. In this way, differential diagnosis became even more challenging throughout the last few years. Use of liver specific contrast agents, as well as CT/MRI perfusion techniques, seem to not only allow earlier detection and more accurate characterization of HCC lesions, but also make it possible to predict response to treatment and survival. Nevertheless, several limitations and technical considerations still exist. This review will describe and discuss all these imaging modalities and their advances in the imaging of HCC lesions in cirrhotic and non-cirrhotic livers. Sensitivity and specificity rates, method limitations, and technical considerations will be discussed.

Advances in Noninvasive Carotid Wall Imaging with Ultrasound: A Narrative Review.

Carotid atherosclerosis is a major cause for stroke, with significant associated disease burden morbidity and mortality in Western societies. Diagnosis, grading and follow-up of carotid atherosclerotic disease relies on imaging, specifically ultrasound (US) as the initial modality of choice. Traditionally, the degree of carotid lumen stenosis was considered the sole risk factor to predict brain ischemia. However, modern research has shown that a variety of other imaging biomarkers, such as plaque echogenicity, surface morphology, intraplaque neovascularization and vasa vasorum contribute to the risk for rupture of carotid atheromas with subsequent cerebrovascular events. Furthermore, the majority of embolic strokes of undetermined origin are probably arteriogenic and are associated with nonstenosing atheromas. Therefore, a state-of-the-art US scan of the carotid arteries should take advantage of recent technical developments and should provide detailed information about potential thrombogenic (/) and emboligenic arterial wall features. This manuscript reviews recent advances in ultrasonographic assessment of vulnerable carotid atherosclerotic plaques and highlights the fields of future development in multiparametric arterial wall imaging, in an attempt to convey the most important take-home messages for clinicians performing carotid ultrasound.

CT imaging of peritoneal carcinomatosis with surgical correlation: a pictorial review.

Cytoreductive surgery in combination with hyperthermic intraperitoneal chemotherapy has revolutionized the survival and the quality of life in selected patients with peritoneal carcinomatosis. Preoperative CT is important for the selection of patients that may benefit from cytoreductive surgery and is useful for surgical planning. There are several tasks for the radiologist during CT interpretation: to describe cancerous implants on a "site-by-site" basis in the peritoneum, ligaments, mesenteries and visceral surfaces, to analyze patterns of involvement and to estimate the disease burden. Knowledge of the correlation between the CT and the surgical findings enhances the understanding of the disease and facilitates the communication between radiologists and surgeons.

Institutional Diagnostic Reference Levels and Peak Skin Doses in selected diagnostic and therapeutic interventional radiology procedures.

PURPOSE: Institutional (local) Diagnostic Reference Levels for Cerebral Angiography (CA), Percutaneous Transhepatic Cholangiography (PTC), Transarterial Chemoembolization (TACE) and Percutaneous Transhepatic Biliary Drainage (PTBD) are reported in this study. MATERIALS AND METHODS: Data for air kerma-area product (PKA), air kerma at the patient entrance reference point (Ka,r), fluoroscopy time (FT) and number of images (NI) as well as estimates of Peak Skin Dose (PSD) were collected for 142 patients. Therapeutic procedure complexity was also evaluated, in an attempt to incorporate it into the DRL analysis. RESULTS: Local PKA DRL values were 70, 34, 189 and 54 Gy.cm2 for CA, PTC, TACE and PTBD respectively. The corresponding DRL values for Ka,r were 494, 194, 1186 and 400 mGy, for FT they were 9.2, 14.2, 27.5 and 22.9 min, for the NI they were 844, 32, 602 and 13 and for PSD they were 254, 256, 1598 and 540 mGy respectively. PKA for medium complexity PTBD procedures was 2.5 times higher than for simple procedures. For TACE, the corresponding ratio was 1.6. PSD was estimated to be roughly 50% of recorded Ka,r for procedures in the head/neck region and 10% higher than recorded Ka,r for procedures in the body region. In only 5 cases the 2 Gy dose alarm threshold for skin deterministic effects was exceeded. CONCLUSION: Procedure complexity can differentiate DRLs in Interventional Radiology procedures. PSD could be deduced with reasonable accuracy from values of Ka,r that are reported in every angiography system.

Magnetic Resonance Imaging patterns in central nervous system lymphomas: A pictorial review.

Five distinctive Magnetic Resonance Imaging (MRI) patterns of Central Nervous System Lymphomas (CNSL) are introduced in this pictorial essay - in an attempt to differentiate lymphoma from other abnormalities with similar MRI appearance, - namely a. solitary supratentorial, b. multiple supratentorial, c. infratentorial, d. intravascular, and e. extraparencymal. Recognition of a specific imaging pattern on brain MR imaging, may facilitate the early diagnosis and prompt treatment initiation, thus improving prognosis of brain lymphoma.

Treatment response classification of liver metastatic disease evaluated on imaging. Are RECIST unidimensional measurements accurate?

The purpose of this study was to evaluate the accuracy of unidimensional measurements (response evaluation criteria in solid tumors, RECIST) compared with volumetric measurements in patients with liver metastases undergoing chemotherapy. Forty-four patients with newly diagnosed liver lesions underwent three MRI examinations at treatment initiation, during chemotherapy, and immediately post-treatment. Measurements based on RECIST guidelines and volume calculations were performed on the "target" lesions (TLs). The two methods were in agreement in 64/77 of patients and 253/301 of individual lesions classification in response categories ("good" agreement, Cohen kappa = 0.735 and 0.741, respectively). In 16.88% of the comparisons the two methods stratified patients to a different response category; 27.6% of TLs did not follow the response category of the patient in whom lesions were located. The actual volume of TLs differs from the calculated volume of a sphere with the same diameter. Our study supports the use of volumetric techniques that may overcome certain disadvantages of unidimensional measurements.

External re-programmation by a new radionuclidic technique of electronic cerebrospinal fluid valve in case of hydrocephalus.

Hydrocephalus is defined as an abnormal enlargement of the ventricles of the brain due to an excessive accumulation of cerebrospinal fluid (CSF) because of a disturbance of its flow, absorption and/or secretion. The usual method of CSF diversion is a ventriculo-peritoneal shunt. Complications of implanted shunt systems include mechanical failure, shunt pathway obstruction, infection, foreign body (allergic) reaction to implants and CSF leakage along the implanted shunt pathway. These problems are solved with the use of programmable ventricular-peritoneal CSF valves. In this case, we describe a radionuclidic method for the control of successful reprogramming of the CSF valve. Furthermore, we analyze some technical data of such a valve-type are essential for the application of the above technique by nuclear medicine physicians. Scintigraphic evaluation of the electronic V-P drainage valve regulation is a noninvasive, not expensive, rapid and safe method with no complications for the patient and provides a reliable proof of the patency of the V-P shunt.

Hepatobiliary scan in Alagille syndrome; arteriohepatic dysplasia.

Arteriohepatic dysplasia or congenital paucity of interlobular bile ducts - Alagille Syndrome, is a well defined syndrome characterized by five major features, including chronic cholestasis, posterior embryotoxon, butterfly-like vertebral arch defects, peripheral pulmonary artery hypoplasia or stenosis and facial dysmorphy. The disease is very rare. Only three cases have been reported in Greece and none with renal involvement. Hepatobiliary scan was a fundamental tool in the patients diagnosis and therefore we present the following case.