There were 17 lesions that simulated restricted diffusion, known as T2 effect or shine through effect, identified with an apparent diffusion coefficient map, where the signal is increased, indicating that the diffusion is not real. This happened in 7 abscess cases, 3 cystic lesions, 4 hemangiomas, 2 regenerative nodules, and one case of liver polycystosis. Examples of the most representative lesions and their respec-tive findings are as follows Restricted diffusion is an ancillary feature favoring malignancy. Radiologists at their discretion may apply restricted diffusion to upgrade category (up to LR-4). If unsure about feature: Do not characterize as feature Both features indicate restricted diffusion. ADC maps (not shown) demonstrate a lower ADC value in the lesion compared with the liver (1.27 × 10 −3 mm 2 /sec and 1.34 × 10 −3 mm 2 /sec, respectively). The other liver lesions show the same characteristics. Figure 4a LIVER MRI IS increasingly used for detection and characterization of focal liver lesions and for the evaluation of diffuse liver disease (1 - 6). MRI has many advantages over computed tomography (CT), mainly lack of ionizing radiation and generally higher accuracy for lesion detection and characterization, especially for small lesions
Malignant lesions show restricted diffusion on DWI and appear brighter. However this finding lacks sufficient specificity to be the sole diagnostic criterion in routine clinical practice. Moreover, combining DWI with contrast enhanced MRI provides high accuracy for detection and characterization of HCCs 11 , 12 Fifty-two of the 230 patients had a total of 55 lesions (23.9%) with restricted diffusion. The mean ADC of all lesions was 809 mm 2 /s, the mean conspicuity score was 2.8. Forty-three of the 55 lesions (78.2%) in 40 patients with known malignant lesions were malignant The vast majority of focal liver lesions are hyperintense on T2-weighted magnetic resonance (MR) images. Rarely, however, hepatic nodules may appear totally or partially hypointense on those images. Causes for this uncommon appearance include deposition of iron, calcium, or copper and are related to Liver lesions are abnormal clumps of cells in your liver, and they are very common. They will be detected in as much as 30% of people over 40 who undergo imaging tests. 1 The majority of liver lesions are benign (not harmful) and don't require treatment. But in some cases, liver lesions are malignant (cancerous) and should be treated
Hepatic hemangioma. Hepatic hemangiomas or hepatic venous malformations are the most common benign vascular liver lesions . They are frequently diagnosed as an incidental finding on imaging, and most patients are asymptomatic. From a radiologic perspective, it is important to differentiate hemangiomas from hepatic malignancy On the post-contrast images, the lesions show heterogeneous enhancement with restricted diffusion in the majority of the lesion. The liver may be surrounded by ascites The theory is that malignant lesions have restricted diffusion while benign lesions do not. However, some of the prior studies were limited by a relatively small number of patients or analyzed only a few types of hepatic lesions The theory is that malignant lesions have restricted diffusion while benign lesions do not, thus the ADC value of benign lesions is significantly higher than that of malignant lesions (7). 1.1. Aim of the stud No restricted diffusion. Masses are almost isointense to liver on T1. The lesions are homogeneously hypervascular and are surrounded by a distinct thin rim of non-enhancement on arterial phase. Lesions demonstrate weaker than blood pool enhancement on the portal venous and equilibrium phase, but no washout
RESULTS: Seventeen patients had re-resected ring-enhancing lesions: 8 cases of radiation necrosis and 9 cases of tumor recurrence. There was significant association between centrally restricted diffusion by visual assessment and radiation necrosis (P = .015) with a sensitivity of 75% and a specificity of 88.9%, a positive predictive value 85.7%, and a negative predictive value of 80% for the. Strong diffusion restriction of the lesion. The lesion is hypervascular mass on arterial phase. On hepatobiliary phase strong hyperintense peripheral enhancement with a large central portion that is hypointense compared to hepatic parenchyma representing a large scar. Findings are typical for focal nodular hyperplasia (FNH)
the lesions were compared with a complete liver MRI protocol. Hyperintensity or isointensity of a lesion in apparent diffusion coefficient map by visual assessment was accepted as unrestricted diffusion and benignity, while hypointensity in any part of a lesion was accepted as restricted diffusion and malignancy On the 1.5 hour delayed image, it is isointense to the remainder of the liver (image 3). On the T2 image, there is faint, low signal septa noted (image 4). On diffusion-weighted imaging (not shown), the lesion does not illustrate restricted diffusion The lesions show restricted diffusion by being bright on the h DWI and dark on the i ADC map: ADC mean = 0.507 × 10 −3 mm 2 /s and ADC min = 0.343 × 10 −3 mm 2 /s. Associated findings: left parasternal and left lateral lower chest wall soft tissue lesions (seen encasing the related ribs) The largest lesion is in the posterior right centrum semiovale measuring 10X6mm. It exhibits no enhancement or adjacent vasogenic edema, however, there is a uniform restricted diffusion of the lesion. So I am wondering what this means? If you can't tell me, than can you tell me what restricted diffusion means Characterisation of liver masses. From a practical point of view, the approach to characterizing a focal liver lesion seen on CT begins with the determination of its density. If the lesion is of near water density, homogeneous, has sharp margins and shows no enhancement, then it is a cyst
However, there are multiple reports of MS lesions with areas of restricted diffusion thought to be associated with active demyelination. 25. Neuromyelitis Optica. Neuromyelitis optica (NMO) is a demyelinating disease caused by an autoantibody to the aquaporin 4 (AQP 4) water channel When the DW MR criteria for benign and malignant liver tumors were applied, 44 of 90 (49%) lesions would have been considered malignant lesions, whereas the other lesions (46 of 90, 51%) would have been considered indeterminate. CONCLUSION: On DW MR images, benign hepatocellular lesions often show findings that suggest restricted diffusion facilitated, but the lesions that restrict diffusion lose less signal. Fig. 2representssignalloss in the gall bladderand liver metastasis in several DWI with different b-values, and in the signallossgraph,byincreasingb-values,thegallbladderloses Fig. 1 - Diffusion of water molecules. (A) Restricted diffusion in the extracellular space due to. Before intravenous contrast, the liver lesion appears hypointense on T1-weighted (a), conventional (b) and fat-suppressed T2-weighted (c) images, with lobulated contour, without restricted diffusion (d, b=600) in 69 lesions Liver Imaging: Lesion characterization Caro-Dominguez P, Gupta A, Chavhan G. Pediatric Radiology In press 35 Qualitative DWI assessment All malignant lesions showed qualitative diffusion restriction Except abscesses none of the benign lesions showed diffusion restriction Excluding abscesses, there was significant associatio
DWI is helpful in lesion characterization of a hepatic focal lesion (HFL) in a cirrhotic liver where a combination of restricted diffusion with arterial hyperenhancement is more likely to be HCC [66, 67]. Also, it is helpful in assessing tumoral versus bland thrombosis of the portal vein Minimal rim enhancement is seen on the arterial-phase and portal-venous-phase images. Profound hypointensity relative to the adjacent liver parenchyma is seen on the 20-minute delayed hepatobiliary-phase images. The lesions exhibit restricted diffusion on diffusion-weighted imaging. Other lesions were identified on other slices (not shown) However, lesions with a high liquid component (such as cysts or liquid in the gallbladder) which have a very long T2 relaxation time, may appear hyperintense in diffusion images, even at very high b-value sequences, simulating restricted diffusion. This is what is known as the T2 shine through effect hanced and contrast enhanced MRI . Most prior studies - have used DW imaging for focal liver l e-sion characterization by enabling measurement of lesion apparent diffusion coefficient (ADC). Sun et al., (2005) measured ADC in four sets (0, 100, 500, 1000) and stated that ADC values had ha- igher st bilization with higher b value
Schaefer et al measured the apparent diffusion coefficient values of these lesions and found the values to be similar to those of gray matter but lower than those of CSF. They postulated that a combination of T2 shine-through and restricted diffusion was responsible for the hyperintensity of these lesions on diffusion images - Main indication in cirrhotic liver is detection of HCC - Consider benign lesions as avoid a false positive - Should we really make a difference between lesion detection and characterization - If you detect a liver metastasis you are very likely to call it a metastasis b0 b100b0 b600 b1000 + * * * Bile viscous fluid
DWI enables the evaluation of restricted diffusion caused by collagen fibers accumulated in the ECM in cirrhotic liver[39-41]. In relation to this, it is important to distinguish METAVIR fibrosis stage 3 or 4 from stages 0 to 2 because patients in the F0-2 grades can be cured by treating the underlying liver disease[ 42 ] Gyriform restricted diffusion (GRD) refers to hyperintense signal involving the cerebral cortex on diffusion-weighted images (DWI) with corresponding hypointensity on apparent diffusion coefficient (ADC) images. These changes are commonly seen following a vascular occlusion, reflecting the limitation of water molecule movement across cell membranes (restricted diffusion) due to the failure of.
Lesions in certain parts of the brain can be a sign of dementia, though this is most common in old age. Type II Diabetes and the Human Immunodeficiency Virus ( HIV ) and related Acquired Immunodeficiency Syndrome (AIDS) may cause spots on the liver, colon, and brain, among other places, and cancers of all forms may also be to blame demonstrated restricted diffusion on the DWI images. The first subject (with metastatic colon cancer) had two positive FDG/DWI liver lesions (Fig 1). One lesion was difficult to see on the PET/CT because of normal background liver uptake and the correlation with DWI improved the clinical confidence that this lesion was indeed hypermetabolic
These changes inhibit the movement of water molecules, with resultant restriction of diffusion and reduction of ADC values in the cancer tissue. In your case, the suspected lesion which shows up in the T2 image ( the area of T2 hypointensity) has no diffusion restriction. This implies that the lesion is benign rather than cancerous Focal Liver Lesion DetectionDWI has demonstrated similar to slightly lower performance for detecting liver metastases when compared with contrast-enhanced T1-weighted imaging (CE T1WI), with DWI being particularly helpful in the detection of lesions Ͻ10 mm (Fig 1). (white circle). (A) HCC is visible as an area of restricted diffusion on. Lesions that have very long T2-values may appear bright even though they do not restrict diffusion. This phenomenon, illustrated below, is known as T2 shine-through. Whenever a bright lesion is encountered on a Trace DW image, the ADC map should be inspected to look for a corresponding area of low signal (restricted diffusion)
To assess the inter/intraobserver variability of apparent diffusion coefficient (ADC) measurements in treated hepatic lesions and to compare ADC measurements in the whole lesion and in the area with the most restricted diffusion (MRDA). Materials and methods Twenty-five patients with treated malignant liver lesions were examined on a 3.0T machine More recently, diffusion-weighted imaging (DWI) has gained recognition for its potential to differentiate metastatic lesions, showing restricted diffusion, from benign lesions, demonstrating free diffusion. Although there are no published reports on DWI for VMC, our findings of free diffusion support a benign diagnosis After bolus injection of 8 mL Gd-EOB-DTPA the lesions displayed as a hypovascular lesions with only moderate contrast agent uptake in the porto-venous phase. In the hepatocyte phase no liver-specific uptake was seen in the lesion. The lesion showed restricted diffusion in the DWI sequence with an ADC value of 0.85 mm 2 /s. Compared to the print. Parikh T, Drew SJ, Lee VS, et al. Focal liver lesion detection and characterization with diffusion-weighted MR imaging: comparison with standard breath-hold T2-weighted imaging. Radiology. 2008;246(3):812-22. Article PubMed Google Scholar 49. Piana G, Trinquart L, Meskine N, Barrau V, Beers BV, Vilgrain V
The detection of incidental adrenal lesions has increased with the widespread use of cross-sectional imaging. 1,2 Incidental adrenal nodules are present in approximately 5% of all abdominal CT examinations in patients with no known malignancy or endocrine abnormality. 3,4 The incidence increases to between 9% and 13% in patients imaged for a. On T1-weighted MR images, the normal signal intensity of the spleen is lower than that of hepatic tissue. Conversely, on T2-weighted images, the spleen shows higher signal intensity, appearing brighter than the liver (Figure 1). The distinctive microscopic anatomy of the spleen may be reflected on diffusion-weighted images (DWI) and ADC maps
Diagnosis of liver metastases: value of diffusion-weighted MRI compared with gadolinium-enhanced MRI. Download. Related Papers. Liver lesion detection and characterization: Role of diffusion-weighted imaging. By Nicola Galea. Diagnosis of liver metastases: Can diffusion-weighted imaging (DWI) be used as a stand alone sequence?. The ADC values of normal liver and each category of liver lesions in the two sequences was compared for agreement using Pearson's coefficient and reliability analysis scale. RESULTS Lesions with restricted diffusion (malignant, abscess) had a higher CNR in RT-DWI than in BH-DWI (p value < 0.001) Detection of benign and malignant liver lesions is aided by the many types of images obtained during a routine hepatic magnetic resonance examination. By combining the information from T1-weighted, T2-weighted, diffusion-weighted, and contrast-enhanced images, MRI greatly increases the chances of detecting a focal liver lesion Both benign and malignant diseases may show restricted diffusion. The high signal intensity of hepatic and extrahepatic lesion on DW images increases lesion conspicuity. Breast Cancer with Hypovascular Liver Metastasis T1 and T2-weighted images (Top) show a 3 cm central liver mass. DW image (Middle Right) shows marked lesion conspicuity A cyst shows no restricted diffusion with high DWI (E) signal and low values on the ADC map (F). A lesion in segment I of the liver (arrow head A-H) is an HCC. Note that this tumor shows heterogeneous enhancement (D) with washout (not shown) and restricted diffusion (high DWI signal and low values on ADC map)
that liver lesions increased in size after 4 months, with the segment VII mass measuring at 40 × 31 mm (white arrow) and the lesion in segment IV clearly visible and 15 × 23 mm in size (white arrowhead). Figure 5 Second abdominal MRI images, two lesions (white arrow and white arrowhead) showed restricted diffusion. (A) Lesions were. They concluded that DWI can be useful in the differentiation of benign and malignant liver lesions. There are many studies related to diagnostic utility of DWI in the renal tumors. Malignant tumors have lower ADC values than benign ones . Restricted diffusion in renal neoplasms is probably multifactorial Purpose: The aim of this project is to investigate the usefulness of the absolute liver lesion ADC value and ratio of Apparent diffusion coefficient (ADC) values of a liver lesion and liver parenchyma to discriminate between a benign and malignant lesion.Methods: Liver MRI scans performed between January 2009 and June 2015 were retrospectively analysed. Scans were performed on either a 1.5 T.
The peribiliary metastasis (arrow) appears hyperintense in T2-W (a and b; see also the biliary tree dilatation due to the lesion), hypointense in T1-W (c and d: T1-W out-in phase sequences) with restricted diffusion for all b values in DWI (e: b50 s/mm 2; f: b600 s/mm 2, g: b800 s/mm 2; h: ADC map) • Diffusion-weighted magnetic resonance imaging is increasingly used for liver lesions. • But ADC values demonstrated only moderate accuracy for differentiation of liver lesions. • T2 relaxation times yielded higher accuracy in diagnosing malignant liver tumours. • Both ADC and T2 values overlapped between focal nodular hyperplasia and malignant lesions. • Nevertheless T2 liver.
Among the solid lesions, in two patients these were intrahepatic (lesions to oxaliplatin and biliary adenoma), with signal hypointense on T 1 W flash in-out phase images and in pre-contrast VIBE T 1 W images, hyperintense on T 2 W imaging; diffusion was restricted from b0 s mm -2 to b800 s mm -2 and a mean ADC value of 1.93 × 10 -3 mm 2. liver imaging as an excellent tool for detection and characterization of focal liver lesions, increasing clinical confidence and decreasing false positives [11-14]. Oncol-ogy is a major field of application of DWI. The analysis of DW images can be done qualitatively and quantitatively, through the apparent diffusion coefficient (ADC) map lesion, this has two major features and therefore is also a LR5 lesion. LR5 lesion: MRI demonstrates a 3.2cm lesion within segment 8 of the liver with hyperenhancement on arterial phase with washout. There is associated mild T2 hyperintensity, mild restricted diffusion with a distinctive rim. This is consistent with a LR5 lesion Background: Diffusion weighted Imaging (DWI) is a useful noninvasive tool in MRI as it can be performed quickly and does not require contrast injection. In addition to it, DWI imaging and apparent diffusion coefficient (ADC) quantification not only can add additional anatomical data about the lesion but can also help in characterization of focal liver lesions into malignant or benign
Lesions that have very long T2-values may appear bright even though they do not restrict diffusion. This phenomenon, illustrated below, is known as T2 shine-through. Whenever a bright lesion is encountered on a Trace DW image, the ADC map should be inspected to look for a corresponding area of low signal (restricted diffusion) Conclusion: Quantitative imaging can substantially benefit from a semi-automated segmentation scheme. Quantitative diffusion MRI results can be predictive of therapeutic outcome in selected patients with liver metastases, but not for all liver metastases, and therefore should be considered to be a restricted biomarker Lesions > 1.5 cm can be routinely characterized on a MDCT Teaching Affiliates of Small Lesion Detection: CT vs. MR CT MR MRI can detect lesions < 1 cm 87-92% In fatty liver, hypovascular lesions are less conspicuous on CT Teaching Affiliates of MR Advantages • Very sensitive for liver lesion detection • Better lesion detection if hepatic. However, apart from tissue cellularity, histological background of the lesion can significantly influence the diffusion characteristics of the lesion. Consequently, even benign lesions with atypical histology can show restricted diffusion leading to potential errors in diagnosis