Purpose of this presentation is to educate non radiologist about basic CT anatomy of abdominal viscera and basic interpretation of very common diseases
Purpose of this presentation is to educate non radiologist about basic CT anatomy of abdominal viscera and basic interpretation of very common diseases
Magnetic Resonance Angiography and VenographyAnjan Dangal
Introduction to MR Angiography and Venography Procedure of Brain . Includes Indication, MRI protocol, planning and anatomy as well as brief intoduction to physics behind MRA and MRV principle.
A triphasic, or triple-phase, CT scan is an enhanced CT technique mostly used to evaluate liver lesions. This technique acquires images at 3 different time points, or phases, following the administration of a contrast.
KEYWORDS
Liver Pancreas Spleen CT angiography Dual-energy CT
KEY POINTS
MDCTA allows acquisition of data with enhanced spatial and temporal resolution that can be reconstructed
for robust preoperative road mapping.
MDCTA can detect normal and variant vascular anatomy as well as allow accurate lesion characterization
within the liver and pancreas.
Using dual-energy CT, virtual unenhanced images can be generated, thereby reducing overall radiation
dose. In addition, material composition allows for robust delineation of enhancement.
Magnetic Resonance Angiography and VenographyAnjan Dangal
Introduction to MR Angiography and Venography Procedure of Brain . Includes Indication, MRI protocol, planning and anatomy as well as brief intoduction to physics behind MRA and MRV principle.
A triphasic, or triple-phase, CT scan is an enhanced CT technique mostly used to evaluate liver lesions. This technique acquires images at 3 different time points, or phases, following the administration of a contrast.
KEYWORDS
Liver Pancreas Spleen CT angiography Dual-energy CT
KEY POINTS
MDCTA allows acquisition of data with enhanced spatial and temporal resolution that can be reconstructed
for robust preoperative road mapping.
MDCTA can detect normal and variant vascular anatomy as well as allow accurate lesion characterization
within the liver and pancreas.
Using dual-energy CT, virtual unenhanced images can be generated, thereby reducing overall radiation
dose. In addition, material composition allows for robust delineation of enhancement.
This slide includes various CT protocol , liver ct triple phase protocol , with important findings, this power-point presentation help a lot for radiologist, radiology resident, radiographers, technician. Thanks.
Triphasic CT (TPCT) Scan of the liver is essential in view of the dual blood supply of the liver. TPCT allows characterisaiton of all liver lesions and close to pathological correlaiton by non invasive imaging alone. Additionally providing segmental vascular analysis as a surgicical guide.
Principle of Radiation Protection- Avinesh ShresthaAvinesh Shrestha
Radiation protection is the science whose aim is to minimize the risks generated by the use of ionizing radiation. Briefly discusses The ICRP System of Radiological Protection, STRUCTURAL SHIELDING OF
IMAGING FACILITIES, APPLICATION OF INDIVIDUAL DOSE LIMTS, RADIATION EXPOSURE IN PREGNANCY, Diagnostic reference level, Personnel Protection in
Medical X-ray Imaging, Dose Optimization in CT, Radiation Protection in Nuclear Medicine.
Brief discussion on the Quality Assurance and Quality Control in Magnetic Resonance Imaging department.
Quality assurance in MRI is a comprehensive concept that comprises all of the management practices developed by the MR imaging team.
Radiation Dose Units and Dose Limits- Avinesh ShresthaAvinesh Shrestha
Describes different units of radiation dose and the dose limits in diagnostic radiology imaging. Discuses different radiation units described by ICRU. Describes different radiation dose limits given by different organizations like ICRP, NCRP, AERB.
The history and fundamental of radiation biology us presented in this presentation. Topics including basic human biology and response to radiation, Law of Bergonie and Tribondeau,
Physical factors that affect radiation response,
Biologic factors that affect radiation response,
Radiation dose-response relationships and 6R's of radiobiology are discussed in this presentation. Topics like Linear energy transfer (LET),
Relative Biologic Effectiveness (RBE),
Protraction and fractionation, age, oxygen enhancement, hormesis, repair, repopulation, re-oxygenation, redistribution, remote (bystander) cellular effects
radio sensitivity etc. are included in concise and comprehensive manner.
Magnetic Resonance Elastography is an advanced imaging technique in MRI. This method is a method of "virtual palpation" of internal organs with the help of MRI.
Echo planar imaging (EPI) is the method of rapid magnetic resonance imaging (MRI), overcoming one of the significant disadvantage of MRI concerning with slow imaging time. However, EPI-MRI imaging comes with it's own unique imaging artifacts.
CT is one of the highest contributor for medical radiation exposure to patients. Some common CT dose descriptors and dose optimizations methods are briefly described in this presentation.
Image Quality, Artifacts and it's Remedies in CT-Avinesh ShresthaAvinesh Shrestha
CT is one of the frequently used diagnostic imaging modalities in Radiology. Knowledge about image quality and artifacts is essential when diagnosing a patient with the help of CT images. Moreover, Radiology Technologist's should be very well aware about the ways to identify and eliminate or minimize the artifacts in CT for better image quality.
Image reconstruction in CT is mostly a mathematical process however, this presentation tries to explain the complicated process of image reconstruction in a visual way, mainly focusing om Filtered back projection, Iterative Reconstruction and AI based image reconstruction.
MDCT Principles and Applications- Avinesh ShresthaAvinesh Shrestha
Multidetector CT (MDCT) is one of the most commonly used imaging modality in the field of Radiology. Development and advancement in MDCT has made it's application as a major component in diagnosis and treatment planning of multitude of disease across the planet. This presentation briefly describes its basic principle and it's wide variety of application in medical imaging.
Application of Perfusion imaging in radiology is increasing with advancement in technology. This presentation briefly describes different perfusion modalities including Computed Tomography, Magnetic Resonance Imaging and Nuclear Medicine. Some of the aspects of perfusion imaging are described in this presentation. This topic was Presented in Radiology department, Institute of Medicine, Maharajgunj.
Venography is a radiological procedure for the evaluation of the veins by the help of intravenous radiological contrast media. It is also known as phlebography. Contrast venography is the gold standard for judging diagnostic imaging methods for deep venous thrombosis; although, because of its cost, invasiveness, the increased sensitivity of sonography to demonstrate pathology and other limitations this test is rarely performed.
This presentation discusses briefly about the anatomy of neck and about different protocols used for CT examination of neck. Also, some pathology are shown in the presentation.
The presentation describes basic anatomy of shoulder and focuses on different radiographic projections used for the evaluation of shoulder. Also, it shows some problems that can be identified in the shoulder radiograph.
Ivu is a radiological investigation for visualization and assessment of the urinary tract.This presentation covers brief anatomy of urinary tract, indication and contraindication,contrast media dose and administration, routine and modified ivu procedure,its complication,ctivu and some abnormalities in the urinary tract.
Intensifying screens are major component of the image receptor used in conventional radiography.Its function is to convert the X-rays into visible light through the process of fluorescence.
Modern medical imaging has been digitized using various technologies which are described here in this presentation.Presented in Department of radiology, ,B.Sc Medical Imaging technology,Institute of Medicine, Nepal.
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
Ethanol (CH3CH2OH), or beverage alcohol, is a two-carbon alcohol
that is rapidly distributed in the body and brain. Ethanol alters many
neurochemical systems and has rewarding and addictive properties. It
is the oldest recreational drug and likely contributes to more morbidity,
mortality, and public health costs than all illicit drugs combined. The
5th edition of the Diagnostic and Statistical Manual of Mental Disorders
(DSM-5) integrates alcohol abuse and alcohol dependence into a single
disorder called alcohol use disorder (AUD), with mild, moderate,
and severe subclassifications (American Psychiatric Association, 2013).
In the DSM-5, all types of substance abuse and dependence have been
combined into a single substance use disorder (SUD) on a continuum
from mild to severe. A diagnosis of AUD requires that at least two of
the 11 DSM-5 behaviors be present within a 12-month period (mild
AUD: 2–3 criteria; moderate AUD: 4–5 criteria; severe AUD: 6–11 criteria).
The four main behavioral effects of AUD are impaired control over
drinking, negative social consequences, risky use, and altered physiological
effects (tolerance, withdrawal). This chapter presents an overview
of the prevalence and harmful consequences of AUD in the U.S.,
the systemic nature of the disease, neurocircuitry and stages of AUD,
comorbidities, fetal alcohol spectrum disorders, genetic risk factors, and
pharmacotherapies for AUD.
Recomendações da OMS sobre cuidados maternos e neonatais para uma experiência pós-natal positiva.
Em consonância com os ODS – Objetivos do Desenvolvimento Sustentável e a Estratégia Global para a Saúde das Mulheres, Crianças e Adolescentes, e aplicando uma abordagem baseada nos direitos humanos, os esforços de cuidados pós-natais devem expandir-se para além da cobertura e da simples sobrevivência, de modo a incluir cuidados de qualidade.
Estas diretrizes visam melhorar a qualidade dos cuidados pós-natais essenciais e de rotina prestados às mulheres e aos recém-nascidos, com o objetivo final de melhorar a saúde e o bem-estar materno e neonatal.
Uma “experiência pós-natal positiva” é um resultado importante para todas as mulheres que dão à luz e para os seus recém-nascidos, estabelecendo as bases para a melhoria da saúde e do bem-estar a curto e longo prazo. Uma experiência pós-natal positiva é definida como aquela em que as mulheres, pessoas que gestam, os recém-nascidos, os casais, os pais, os cuidadores e as famílias recebem informação consistente, garantia e apoio de profissionais de saúde motivados; e onde um sistema de saúde flexível e com recursos reconheça as necessidades das mulheres e dos bebês e respeite o seu contexto cultural.
Estas diretrizes consolidadas apresentam algumas recomendações novas e já bem fundamentadas sobre cuidados pós-natais de rotina para mulheres e neonatos que recebem cuidados no pós-parto em unidades de saúde ou na comunidade, independentemente dos recursos disponíveis.
É fornecido um conjunto abrangente de recomendações para cuidados durante o período puerperal, com ênfase nos cuidados essenciais que todas as mulheres e recém-nascidos devem receber, e com a devida atenção à qualidade dos cuidados; isto é, a entrega e a experiência do cuidado recebido. Estas diretrizes atualizam e ampliam as recomendações da OMS de 2014 sobre cuidados pós-natais da mãe e do recém-nascido e complementam as atuais diretrizes da OMS sobre a gestão de complicações pós-natais.
O estabelecimento da amamentação e o manejo das principais intercorrências é contemplada.
Recomendamos muito.
Vamos discutir essas recomendações no nosso curso de pós-graduação em Aleitamento no Instituto Ciclos.
Esta publicação só está disponível em inglês até o momento.
Prof. Marcus Renato de Carvalho
www.agostodourado.com
ARTIFICIAL INTELLIGENCE IN HEALTHCARE.pdfAnujkumaranit
Artificial intelligence (AI) refers to the simulation of human intelligence processes by machines, especially computer systems. It encompasses tasks such as learning, reasoning, problem-solving, perception, and language understanding. AI technologies are revolutionizing various fields, from healthcare to finance, by enabling machines to perform tasks that typically require human intelligence.
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
Couples presenting to the infertility clinic- Do they really have infertility...Sujoy Dasgupta
Dr Sujoy Dasgupta presented the study on "Couples presenting to the infertility clinic- Do they really have infertility? – The unexplored stories of non-consummation" in the 13th Congress of the Asia Pacific Initiative on Reproduction (ASPIRE 2024) at Manila on 24 May, 2024.
New Directions in Targeted Therapeutic Approaches for Older Adults With Mantl...i3 Health
i3 Health is pleased to make the speaker slides from this activity available for use as a non-accredited self-study or teaching resource.
This slide deck presented by Dr. Kami Maddocks, Professor-Clinical in the Division of Hematology and
Associate Division Director for Ambulatory Operations
The Ohio State University Comprehensive Cancer Center, will provide insight into new directions in targeted therapeutic approaches for older adults with mantle cell lymphoma.
STATEMENT OF NEED
Mantle cell lymphoma (MCL) is a rare, aggressive B-cell non-Hodgkin lymphoma (NHL) accounting for 5% to 7% of all lymphomas. Its prognosis ranges from indolent disease that does not require treatment for years to very aggressive disease, which is associated with poor survival (Silkenstedt et al, 2021). Typically, MCL is diagnosed at advanced stage and in older patients who cannot tolerate intensive therapy (NCCN, 2022). Although recent advances have slightly increased remission rates, recurrence and relapse remain very common, leading to a median overall survival between 3 and 6 years (LLS, 2021). Though there are several effective options, progress is still needed towards establishing an accepted frontline approach for MCL (Castellino et al, 2022). Treatment selection and management of MCL are complicated by the heterogeneity of prognosis, advanced age and comorbidities of patients, and lack of an established standard approach for treatment, making it vital that clinicians be familiar with the latest research and advances in this area. In this activity chaired by Michael Wang, MD, Professor in the Department of Lymphoma & Myeloma at MD Anderson Cancer Center, expert faculty will discuss prognostic factors informing treatment, the promising results of recent trials in new therapeutic approaches, and the implications of treatment resistance in therapeutic selection for MCL.
Target Audience
Hematology/oncology fellows, attending faculty, and other health care professionals involved in the treatment of patients with mantle cell lymphoma (MCL).
Learning Objectives
1.) Identify clinical and biological prognostic factors that can guide treatment decision making for older adults with MCL
2.) Evaluate emerging data on targeted therapeutic approaches for treatment-naive and relapsed/refractory MCL and their applicability to older adults
3.) Assess mechanisms of resistance to targeted therapies for MCL and their implications for treatment selection
- Video recording of this lecture in English language: https://youtu.be/lK81BzxMqdo
- Video recording of this lecture in Arabic language: https://youtu.be/Ve4P0COk9OI
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
3. Introduction
With MDCT multiphasic examinations of the liver and pancreas can be performed without
compromises with regard to spatial or temporal resolution.
However, an adequate examination technique is still critical for sensitive detection and specific
characterization of lesions.
The criteria for the characterization of lesions are derived from their behavior and degree of
contrast agent enhancement in the different vascular phases of CT.
For a valid characterization usually at least two different phases are mandatory, so that changes of
enhancement over time (e.g., wash-in and wash-out of contrast agent) can be appreciated.
4. Basic Concepts for Liver Imaging
The conspicuity of a liver lesion depends on the attenuation difference between the lesion and the
normal liver.
On a non enhanced CT-scan (NECT) liver tumors usually are not visible, because the inherent contrast
between tumor tissue and the surrounding liver parenchyma is too low.
Only a minority of tumors contain calcifications, cystic components, fat or hemorrage and will be
detected on a NECT.
So i.v. contrast is needed to increase the conspicuity of lesions.
5. Basic Concepts for Liver Imaging
When we give i.v. contrast, it is important to
understand, that there is a dual blood supply to
the liver.
Normal parenchyma is supplied for 80% by the
portal vein and only for 20% by the hepatic artery,
so it will enhance in the portal venous phase.
This difference in blood supply results in different
enhancement patterns between liver tumors and
normal liver parenchyma in the various phases of
contrast enhancement
6. Small Hepatocellular carcinoma in
cirrhotic liver not visible on NECT
(left), clearly visible in arterial phase
(middle) and not visible in portal
venous phase (right)
7. Arterial Vs Parenchymal Enhancement
Enhancement of the arterial phase is dependent on the:
contrast medium injection rate,
injection duration, and
the time of the scan performed relative to the contrast bolus.
Arterial opacification can primarily be controlled by the:
iodine administration rate, which is further dependent on the flow rate and the
concentration of medium administered.
It is important that the injection duration be longer than the scanning time to ensure strong
vascular enhancement by the recirculation of contrast.
8. Arterial Vs Parenchymal Enhancement
On the other hand, the parenchymal enhancement is
independent of the injection flow rate and
depends on the total volume (dose) of contrast administered.
Thus, to obtain optimal liver parenchymal enhancement, a sufficient volume of contrast medium is
required approximately 120–150 cc of 370 mgI contrast agent.
The iodine dose is directly proportional to the
contrast volume administered and/or
the iodine concentration of the contrast medium.
11. Different Phases of Hepatic Vascular and Parenchymal
Enhancement
According to the different enhancement curves of the hepatic artery, portal vein, and hepatic
parenchyma, four phases can be distinguished:
1. Early arterial phase (EAP)
2. Late arterial phase (LAP)
3. Portal venous phase (PVP)
4. Equilibrium phase (EQP)
12. Different Phases of Hepatic Vascular and Parenchymal
Enhancement
Early arterial phase (EAP)
appears 20–25 s after administration of contrast material when there is conspicuous enhancement
in the hepatic arteries compared with almost no enhancement of liver parenchyma or
hypervascular lesions.
typically provides the least information for imaging the liver, since the contrast media at that time
has accumulated neither in hypervascular liver lesions nor in liver parenchyma.
this phase is well suited for CT angiography when used to evaluate the anatomical configuration of
hepatic arteries prior to liver transplantation, hepatic tumor resection, or arterial
chemoembolization.
13. Different Phases of Hepatic Vascular and Parenchymal
Enhancement
Early arterial phase (EAP)
For optimum timing for EAP scanning, an automated triggering system can be used.
The scanner is typically set at the top of the liver with the trigger placed in the descending
thoracic aorta.
When the trigger, reaches a predefined attenuation (typically 90–100 HU), the scan begins for the
EAP.
15. Different Phases of Hepatic Vascular and Parenchymal
Enhancement
Late arterial phase (LAP)
appears at about 30–35 s following initiation of contrast material administration.
using the automated triggering technique, to avoid the EAP, an additional 8- to 10-s delay is
required.
The LAP is also referred to as the portal vein inflow phase, since the portal vein is already starting
to enhance during this phase.
The hepatic arterial systems as well as prominent neovasculature of hypervascular hepatic
neoplasms continue to enhance during the LAP, while there is only minimal enhancement of hepatic
parenchyma.
16. Different Phases of Hepatic Vascular and Parenchymal
Enhancement
Late arterial phase (LAP)/ portal vein inflow phase
At this point, there is a maximum attenuation difference between hypervascular liver lesions and
the surrounding liver parenchyma.
Thus, LAP is the optimal phase for detecting hypervascular neoplasms of the liver.
acquisition of the LAP together with the PVP is considered sufficient for detection of HCC with
MDCT.
18. Different Phases of Hepatic Vascular and Parenchymal
Enhancement
Portal venous phase (PVP) or hepatic venous phase
appears at about 60–70 s following initiation of a contrast media bolus, when the enhancement of liver
parenchyma reaches its peak and the portal vein and hepatic veins are well enhanced.
For accurate timing of the PVP in a single-phase exam, automated scanning technology instead of a
fixed time delay is preferred.
The trigger is placed in liver parenchyma, and when attenuation reaches a predefined threshold (50–70
HU), the table is moved to the top of the liver and the diagnostic scan initiated.
For a dual-phase exam, there is a fixed time delay of 40 s following the end of the LAP.
19. Different Phases of Hepatic Vascular and Parenchymal
Enhancement
Portal venous phase (PVP) or hepatic venous phase
Hypovascular tumors are optimally detected during the PVP when enhancement of liver parenchyma is
maximal and there is the greatest liver-to-lesion attenuation difference.
For detection of these tumors, a single scan during the PVP is sufficient, since there is no further
advantage performing unenhanced or arterial-phase imaging.
The PVP is also the appropriate phase for visualization and evaluation of intrahepatic bile ducts, when
there is the greatest difference of attenuation between the maximally enhanced liver parenchyma and
the hypoattenuating intraductal bile
20. shows enhancement of main portal vein
and its branches in hepatic parenchyma
and enhancement of hepatic veins (arrows)
21.
22. Different Phases of Hepatic Vascular and Parenchymal
Enhancement
Equilibrium phase (EQP), or interstitial phase
appears at approximately 3 min postinjection, when there is an increased diffusion of contrast
media into liver parenchyma and attenuation difference between parenchyma and vessels is
minimal.
Washout of the contrast material in different liver lesions may vary vastly depending on their
histological nature.
23. Different Phases of Hepatic Vascular and Parenchymal
Enhancement
Equilibrium phase (EQP), or interstitial phase
One clear indication for acquiring images during the EQP includes intrahepatic cholangiocarcinoma.
This tumor may accumulate the contrast agent and show a delayed washout compared with
surrounding liver parenchyma. This delay causes hyperattenuating lesions.
By comparison, HCC may show a faster washout during the EQP relative to the surrounding liver
parenchyma, representing a hypoattenuating mass.
24. Following an intravenous bolus of contrast
material, the hepatic artery enhances first at
approximately 15 s and reaches peak
attenuation at approximately 30 s. After the
contrast medium returns from the splanchnic
system, the portal vein starts to enhance at
around 30 s. Enhancement of liver
parenchyma begins later, reaching a plateau
at 60–70 s. The plateau may last up to 20–30
s. Finally, there is the equilibrium phase
(EQP) (3 min and later), which occurs when
the amount of contrast material in the intra-
and extravascular extracellular space is
essentially the same.
25. Multiphase Imaging of Liver
In the arterial phase hypervascular tumors will enhance via the hepatic artery, when normal
liver parenchyma does not yet enhances, because contrast is not yet in the portal venous
system. These hypervascular tumors will be visible as hyperdense lesions in a relatively
hypodense liver. However when the surrounding liver parenchyma starts to enhance in the
portal venous phase, these hypervascular lesion may become obscured.
In the portal venous phase hypovascular tumors are detected, when the normal liver
parenchyma enhances maximally. These hypovascular tumors will be visible as hypodense
lesions in a relatively hyperdense liver.
In the equilibrium phase, tumors become visible, that either loose their contrast slower than
normal liver, or wash out their contrast faster than normal liver parenchyma. These lesions will
become either relatively hyperdense or hypodense to the normal liver.
26.
27. Detection of a lesion depends on difference in attenuation between liver and lesion.
LEFT: Arterial phase showing hypervascular FNH MIDDLE: Portal venous phase
showing hypovascular metastasis RIGHT: equilibrium phase showing relatively dense
cholangiocarcinoma
28. Unenhanced Phase
There are selected cases in which an unenhanced CT scan of the liver is helpful and recommended.
Reasonable clinical indications for a non-contrast hepatic CT include:
Depiction of acute hemorrhage of the liver
Delineation of siderotic nodules
Detection and characterization of hepatic calcification (e.g., calcified metastases,, hydatid cysts)
Evaluation of parenchymal liver diseases (e.g., fatty infiltration, hepatic cirrhosis,
hemochromatosis)
Follow-up CT scan after embolization of hypervascular liver lesions.
29. Arterial phase imaging
Optimal timing and speed of contrast injection are very important for good arterial phase imaging.
Hypervascular tumors will enhance optimally at 35 sec after contrast injection (late arterial
phase).
This time is needed for the contrast to get from the peripheral vein to the hepatic artery and to
diffuse into the liver tumor.
30. two phases of arterial imaging
at 18 and 35 seconds. In the
early arterial phase we nicely
see the arteries, but we only
see some irregular
enhancement within the liver.
In the late arterial phase we
can clearly identify multiple
tumor masses.
Arterial phase imaging
31. Timing of scanning is important, but almost as important is speed of contrast injection.
For arterial phase imaging the best results are with an injection rate of 5ml/sec.
There are two reasons for this better enhancement:
at 5ml/sec there will be more contrast delivered to the liver when you start scanning and
this contrast arrives in a higher concentration.
Arterial phase imaging
32. Arterial phase imaging
patient with cirrhosis examined
after contrast injection at
2.5ml/sec and at 5ml/sec.
At 5ml/sec there is far better
contrast enhancement and better
tumor detection.
33.
34.
35.
36.
37. Portal Venous phase
Portal venous phase imaging works on the opposite idea.
We image the liver when it is loaded with contrast through the portal vein to detect
hypovascular tumors
The best moment to start scanning is at about 75 seconds, so this is a late portal venous phase,
because enhancement of the portal vein already starts at 35 sec in the late arterial phase.
This late portal venous phase is also called the hepatic phase because there already must be
enhancement of the hepatic veins. If we do not seen enhancement of the hepatic veins, it’s too
early.
If we only do portal venous imaging, for instance if we are only looking for hypovascular
metastases in colorectal cancer, fast contrast injection is not needed, because in this phase the
total amount of contrast is more important and 3ml/sec will be sufficient.
38. Portal Venous phase
Hypovascular metastases
seen as hypodense lesions
in the late portal venous
phase.
39.
40.
41. Equilibrium Phase
The equilibrium phase is when contrast is moving away from the liver and the liver starts to
decrease in density.
This phase begins at about 3-4 minutes after contrast injection and imaging is best done at 10
minutes after contrast injection.
This phase can be valuable if you're looking for:
fast tumor washout in hypervascular tumors like HCC or retention of contrast in the blood pool
as in hemangiomas, or
the retention of contrast in fibrous tissue in capsules (HCC) or scar tissue (FNH,
Cholangiocarcinoma).
43. Equilibrium Phase
Relative hyperdense lesions in the delayed phase
Fibrous tissue that's well organized and dense is
very slow to let iodine in.
Once contrast gets in however, it is equally slow
to get back out in the equilibrium phase.
So when the normal liver parenchyma washes
out, the fibrous components of a tumor will look
brighter than the background liver tissue.
Cholangiocarcinoma may have a fibrous stroma
and in the delayed phase it may be the only time
when you see the tumor (figure).
Small cholangiocarcinoma not visible in
portal venous phase (left), but seen as
relative hyperdense lesion in the delayed
phase (right).
44. Equilibrium Phase
Relative hypodense lesions in the delayed phase
the importance of the delayed phase in a cirrhotic
patient with an HCC is demonstrated.
Notice that you do not see the tumor on the
nonenhanced scan and also not in the portal venous
phase. This is often the case and demonstrates the
importance of the arterial phase.
Now the issue at hand is in small enhancing lesions in a
cirrhotic liver whether it is a benign lesion like a
regenerating nodule or a HCC.
In the delayed phase we see that the tumor is washed
out more than the surrounding liver parenchyma.
HCC in a cirrhotic liver. Notice fast wash out in
equilibrium phase compared to surrounding liver
parenchyma.
45. Equilibrium Phase
Relative hypodense lesions in the delayed phase
Benign lesions typically will not show this kind of wash
out.
For instance a FNH or adenoma will show fast
enhancement in the arterial phase, become isodense in
the portal venous phase, but it will stay isodense with
liver in the equilibrium phase.
These benign tumors do not have enough neoplastic
neovascularity to have a fast wash out.
Especially in cirrhotic patients you have to rely heavily
on this delayed phase to differentiate benign little
enhancing lesions from small HCC's.
HCC in a cirrhotic liver. Notice fast wash out in
equilibrium phase compared to surrounding liver
parenchyma.
46.
47.
48.
49.
50.
51. Tailored CT protocol
We have to adapt our protocol to the type of scanner, the speed of contrast injection and to the
kind of patient that we are examining.
If we have a single slice scanner, it will take about 20 seconds to scan the liver.
For late arterial phase imaging 35 sec is the optimal time, so we start at about 25 seconds and
end at about 45 seconds.
However if we have a 64-slice scanner, it’s possible able to examine the whole liver in 4 seconds.
So we start scanning at about 33 seconds, which is much later.
In aterial phase imaging the time window is narrow, since we have only limited time before the
surrounding liver will start to enhance and obscure a hypervascular lesion.
52. Tailored CT protocol
For portal venous phase imaging it is different
Here we don't want to be too early, because we want to load the liver with contrast and it takes time
for contrast to get from the portal vein into the liver parenchyma.
Besides we have more time, because the delayed or equilibrium phase starts at about 3-4 minutes.
So we start at 75 seconds with whatever scanner we have.
Only when we inject with high speed at 5ml/sec we may start earlier at about 65-70 seconds.
54. Contrast Volume
Reduced volumes of contrast injection are not favored for liver imaging due to concerns about image
quality.
Also, the volume of contrast to be injected varies depending on the iodine concentration in the contrast
medium.
Usually in cases of MDCT liver imaging, 120–150 cc of 300 mgI/ml of nonionic contrast is injected at a
rate of 4 cc/s.
On the other hand, if 370 mgI/ml is used, only 80–100 cc would be required, but this needs to be
balanced with a slightly higher injection rate of 4–5 cc/s.
55. Contrast Volume
Thus, with use of higher or lower iodine concentration contrast media, appropriate adjustments in
injection rate and contrast volume are needed
For most applications, 38–44 g of iodine is recommended
Total iodine doses less than 30 g are also not recommended, as the duration and magnitude of hepatic
enhancement will decrease, resulting in a lower detection rate of focal liver lesions.
56. Rationale for High-Concentration Contrast Medium
The use of high iodine concentration contrast medium has gained importance in patients with
decreased cardiac output, obesity, in conditions such as cirrhosis of the liver or portal vein
thrombosis,
maximum hepatic enhancement in obese patients is significantly lower than in those who are
lighter in weight.
This could be attributed to the decreased level of perfusion of the liver in obese patients
57. Rationale for High-Concentration Contrast Medium
in cases of liver cirrhosis, due to decreased portal perfusion, the peak contrast enhancement
in liver is late, and usually, the plateau of contrast enhancement occurs in the late portal
phase.
The injection of contrast medium with standard iodine concentration could increase the
possibility of missing hypovascular metastases in heavy patients or in patients with cirrhosis
or chronic hepatitis.
the lesion-to-liver contrast can be improved when high iodine concentration contrast medium
is used
58.
59. Liver MDCT: Siemens Definition Edge 128 CT scanner (Siemens Medical Solutions, Malvern, PA, USA).
Intravenous (IV) contrast: 370 mg/mL.
Weight-based dose: <60kg: 80 mL, 60-90kg: 90 mL, >90kg: 120 mL.
IV gauge: 18 gauge.
IV contrast rate: 4 mL/s.
Oral contrast: water.
Bolus tracking: 150 HU of abdominal aorta measured at the level of the mid liver, monitored delay of 10 seconds and scan delay
of 15 seconds for arterial phase.
60.
61. Dual-Energy Computed Tomography
Imaging at a lower energy of 80 kVp can improve hypervascular lesion conspicuity as well
as reduce the effective radiation dose, and the amount of iodinated contrast required
for an examination.
The disadvantage of using a lower kVp is that image noise increases due to attenuation
of the x-ray beam by the patient, which is exacerbated in larger patients.
62. Hepatocellular carcinoma (A, B, arrow) shown during
the late arterial phase during dual-energy acquisition
is more conspicuous on the output of the 80-kV
image (A) compared with 140-kV image (B). Both the
portal phase image at 120 kV (C) and the prior late
arterial phase at a single-energy 120-kV examination
(D) show the tumor, but with decreased conspicuity
compared with the 80-kV image. Note increased
noise in the 80-kV examination (A).
63. Radiation protection/dose
Dose reduction techniques: automatic exposure control (mA) and iterative slice reconstruction.
Expected DRL:
CTDIvol per sequence (mGy) – 14
DLP per complete examination (mGy cm) – 910
64.
65. The Biliary System
MDCT is not generally considered to be a first-line imaging technique for patients with suspected
biliary pathology
The intrahepatic bile ducts, which are linear structures accompanying the portal vein and hepatic
arterial branches, can be best visualized during the PVP when there is an optimal attenuation
difference between hypodense bile ducts and the adjacent enhanced vessels and parenchyma
role of MDCT in the evaluation of different biliary pathologies includes:
Cholangiocarcinoma
Primary Sclerosing Cholangitis
Acute and Chronic Cholecystitis
Gallbladder Carcinoma
66. Early primary sclerosing cholangitis during the unenhanced state (a), LAP (b), PVP (c). Note the scattered
intrahepatic ductal dilatation
69. Concepts in Pancreatic Imaging
Detection of lesions within the pancreas on CT depends largely on the enhancement pattern of
the lesion and the alteration in contour of the normal pancreas.
Before initiation of contrast-enhanced MDCT of the pancreas, administration of negative oral
contrast medium is performed to distend the stomach and duodenum, which facilitates detection
of abnormalities in the pancreatic bed.
The use of negative oral contrast medium has an added advantage in that it does not mask
radiopaque stones in the common bile duct, and it may aid in the evaluation of gastric and
duodenal wall lesions
The administration of oral contrast material is necessary to improve delineation of the pancreatic
head against the duodenum.
70. Concepts in Pancreatic Imaging
Administration of a positive oral contrast material may sometime impair the delineation of the
pancreatic head if dilution of the ingested contrast material by retained fluid in the stomach yields
the same CT density as the pancreatic head enhanced by intravenous contrast material.
Thus, Richter et al. (1998) developed the concept of hydro-CT of the pancreas: Patients are to drink
at least 1,000 ml of water prior to the examination.
Filling of the stomach and duodenum with water, which acts as a negative contrast agent, allows
excellent delineation of the pancreatic head, which improves detection of pancreatic tumors
adjacent to the duodenum
When initial scans fail to differentiate the margins of the pancreas from the duodenum, the patient
is often given additional oral contrast material and additional slices are obtained with the patient
lying in a right decubitus positions
71. Indications
Typical indications include an evaluation of the following:
jaundice
evaluation of pancreatic tumors and/or cystic lesions
acute or chronic pancreatitis
complications of pancreatic diseases
unclear findings on ultrasound or CT abdomen
pancreatic interventions (e.g. CT-guided biopsy, drainage)
72.
73. Standard CT for Pancreatic Tumor Evaluation
A pancreas-specific protocol for pancreatic cancer typically utilizes a thin-section, multiphase
technique, with either two phase or four phase scans.
Two phase scan protocol is more commonly used than four phase protocols, and include pancreatic
phase (also known as the late arterial phase, 35–50 s after the start of contrast injection) and portal
venous phase images (55– 70 s after the start of contrast injection).
Pancreatic phase images show peak pancreatic parenchymal enhancement, and therefore provide the
best lesion to pancreas contrast, and can be useful in identifying vascular involvement by pancreatic
cancer.
Portal phase images are helpful to assess the extent of the venous involvement as the portomesenteric
venous system is well opacified and to identify possible liver metastases.
74. Standard CT for Pancreatic Tumor Evaluation
Four phase scans include precontrast images and early arterial phase (CT angiography phase, 17–25 s
after the start of contrast injection) in addition to pancreatic phase and portal venous phase images.
Noncontrast images can be helpful in identifying pancreatic calcifications, ductoliths, and biliary
stones, and therefore, generally, there is no diagnostic need for noncontrast scans in patients with
suspected pancreatic tumors unless there is coexistent chronic pancreatitis.
In addition, early arterial phase imaging is good for evaluation of vascular anatomy
77. SPLIT BOLUS
Recently, utilization of split-bolus injection in conjunction with spectral CT has been shown to
improve pancreatic tumor conspicuity and reduce radiation dose by combing the pancreatic and
portal venous phases into one scan.
This is done by initially administering 100 mL iodinated intravenous contrast before the CT for the
portal venous phase and then injecting an additional 40 mL of contrast 35 seconds later to enhance
the pancreatic phase.
Bolus tracking initiates scanning 15 seconds after the abdominal aorta reaches an attenuation of 280
HU. Images are then reconstructed at 60 and 77 keV. This scanning protocol offers marked reduction
in radiation dose and higher tumor conspicuity with the 60 keV compared with a standard pancreatic
protocol CT.
78. Post-process of MDCT for pancreatic
neck cancer. (a) Axial CT scan that
obtained during pancreatic phase
shows a 2.5 cm, ill-defined
hypovascular mass (arrow) in the
pancreas neck. (b) Curved
multiplanar reconstruction (MPR)
image along the pancreatic duct
demonstrates dilatation of the
upstream pancreatic duct
(arrowheads), and decreased
enhancement of parenchymal due to
associated pancreatitis. (c) Oblique
coronal MPR image, mass encases
the gastroduodenal artery (arrow)
while preserving fat plane between
CHA (open arrow) and mass. (d) On
coronal maximum intensity projection
(MIP) image, the main portal vein
and proximal superior mesenteric
vein show a long luminal narrowing
(arrow) over 2.5 cm due to tumor
involvement
79. Pancreas cancer on dual-energy CT.
(a–c) Dual-energy CT examination
composed of (a) virtual noncontrast,
(b) virtual monoenergetic spectral
image (VMS, reconstruction on 50
KeV monoenergy level), (c) iodine
map images. Compare to (d)
conventional 120 kVp pancreatic
phase image, an ill-defined
hypovascular mass (arrow) in
pancreas body is more clearly
delineated on (b) VMS and (c) iodine
map image
80.
81.
82.
83.
84.
85.
86. Pancreatic carcinoma is best imaged at 35 sec p.i.
Liver metastases are best imaged at 70 sec p.i.
87. Reference
Hammerstingl R, Vogl T. Abdominal MDCT: protocols and contrast considerations. European
Radiology Supplements. 2005;15(S5):e78-e90.
Price M, Patino M, Sahani D. Computed Tomography Angiography of the Hepatic, Pancreatic,
and Splenic Circulation. Radiologic Clinics of North America. 2016;54(1):55-70.
Ji H, McTavish J, Mortele K, Wiesner W, Ros P. Hepatic Imaging with Multidetector CT.
RadioGraphics. 2001;21(suppl_1):S71-S80.
https://radiologyassistant.nl/abdomen/liver/characterisation-of-liver-masses
https://radiologyassistant.nl/more/ct-protocols/ct-contrast-injection-and-protocols
https://www.youtube.com/watch?v=z_M3oQytmGY
The patient is given 600 ml of water 30 minutes prior to the scan. The water acts as an upper GI contrast medium and facilitates vascular/3D reformatting with reduced artefact from a contrast-enhanced intestine.
scan reference point is at the level of the mid-sternum.
the fast and reliable approach of MDCT makes it an indispensable modality for imaging of liver pathologies.
The main area of improvisation by MDCT for liver imaging appears to be in detection and characterization of small liver malignancies with better characterization of benign pathologies and vascular flow details
Liver tumors however get 100% of their blood supply from the hepatic artery, so when they enhance it will be in the arterial phase.
For example, for vascular mapping of the liver(CTA), arterial phase imaging is of paramount importance, and administration of smaller volume of high-concentration contrast medium at a higher rate would suffice. Contrast material later enters the extracellular space by diffusion, and this reduces the conspicuity of the liver lesion and its contrast with the surrounding parenchyma, later causing obscuration of the lesion. This is called the equilibrium phase, and it is important that the scan be completed well before this stage sets in.
For example, for vascular mapping of the liver(CTA), arterial phase imaging is of paramount importance, and administration of smaller volume of high-concentration contrast medium at a higher rate would suffice. Contrast material later enters the extracellular space by diffusion, and this reduces the conspicuity of the liver lesion and its contrast with the surrounding parenchyma, later causing obscuration of the lesion. This is called the equilibrium phase, and it is important that the scan be completed well before this stage sets in.
For example, for vascular mapping of the liver(CTA), arterial phase imaging is of paramount importance, and administration of smaller volume of high-concentration contrast medium at a higher rate would suffice. Contrast material later enters the extracellular space by diffusion, and this reduces the conspicuity of the liver lesion and its contrast with the surrounding parenchyma, later causing obscuration of the lesion. This is called the equilibrium phase, and it is important that the scan be completed well before this stage sets in.
Following a 15-s delay after initiation of contrast material administration, a low-dose image is acquired every 3 s.
Following a 15-s delay after initiation of contrast material administration, a low-dose image is acquired every 3 s.
when desmoplastic
A hamartoma is a noncancerous tumor made of an abnormal mixture of normal tissues and cells from the area in which it grows.
Siderotic:Pigmented by iron. Containing an excess of iron.
Hepatic siderotic nodules are a type of regenerative nodule formed in a cirrhotic liver. They occur in hepatic hemosiderosis.
epithelioid hemangioendothelioma
Notice that in the late arterial phase there has to be some enhancement of the portal vein.The only time that an early arterial phase is needed is when you need an arteriogram, for instance as a roadmap for chemoembolization of a liver tumor.
To impair peristaltic contractions of the stomach and duodenum during the helical CT acquisition, intravenous administration of Buscopan ® is recommended.
. With the evolution of MDCT and the dramatic shortening of acquisition times, the administration of scopolamine (e.g., Buscopan®) to paralyze the stomach is not necessary anymore.
Infiltration is the movement of cancer cells from their normal location into the surrounding non-cancerous tissue. Another word for infiltration is invasion. Infiltration is an important feature that pathologists look for when trying to decide if a tumour is benign (non-cancerous) or malignant (cancerous).
In brevity, split-bolus CT technique combines pancreatic phase and portal venous phase in a single scan: 70 s before CT, 100 mL of contrast material is injected for the portal venous phase followed approximately 35 s later by injection of 40 mL of contrast material to boost the pancreatic phase It may provide optimal synchronous arterial and mesenteric venous opacification evaluating potential tumor resectability and reduce radiation dose