الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Triphasic MRI of the liver is a relatively recent diagnostictool after the new sequences which have been used as well as the new generation of MRI machines. MRI can be a valuable addition to the work-up of hepatic lesions in conjunction with ultrasound and triphasic CT.
The aim of this study was:
1- To standardize the MRI sequences used to perform the study and so we can tailor the sequences used in order to get benefit from the study and try to reach a final diagnosis
2- To describe the role of MRI using the new pulse sequences and triphasic study in characterization and diagnosis of different types of focal hepatic lesions.
3- To study the role of MRI in combination with triphasic CT in order to reach the final diagnosis of hepatic lesions or at least narrow the list of differential diagnosis and hence decrease the rate of biopsy from the hepatic lesions.
4- To highlight the MRI as a problem solving technique in difficult cases.
5- To evaluate the role of MRI in follow up of post management cases either post TACE or RFA and monitoring the response to treatment.
Our study was performed on patients who presented to our Radio-diagnosis department and underwent ultrasonographic and /or triphasic CT examination and consequently, were scheduled for further assessment by MRI in orderto confirm the CT diagnosis or in a trial to reach the final diagnosis in a time interval from December 2009 till December 2011 with a total number of patients of 128.
Our patients were classified into: group A with cirrhotic liver included 66 patient(52%) and group B with non cirrhotic liver included 62 patients (48%).
All patients underwent:
1- Thorough history taking including: the main patient complain, presence of hepatitis viral infection (which is confirmed by laboratory investigation), complain of liver insufficiency (jaundice, hematemsis and encephalopathy) and history of previously diagnosed primary tumors and if present what was the management.
2- Laboratory investigation including the liver functions, tumor marker (AFP). As well as renal function (creatinine) to asses creatinine clearance before contrast administration in triphasic study.
3- Pre MRI examinations:
a- U/S of the abdomen mainly for assessment of the liver (presence of cirrhosis, focal hepatic lesion and its nature), presence of any mass elsewhere in the abdomen, enlarged lymph nodes.
b- Triphasic CT of the liver to asses:
i- The liver condition as regard presence or absence of cirrhosis, hepatic lesion as regard the number, size , density and enhancement dynamics in triphaisc study.
ii- General examination of the abdomen and pelvis; the whole organs, +/- (ascites, enlarged LNs, metastases elsewhere e.g lung, bone, peritoneum)which help in diagnosis and staging of tumor if present.
- MRI examination
i- MRI of the liver entailing various sequences with T2-fat suppressed, IP/OP, SSFP,and DWI with variable b values (50-1000 s/mm2) followed by triphasic 3-D spoiled gradient-echo pre-and post-contrast.
ii- Image post-processing either automatically generated by the MRI machine or manual by the radiologists was performed to prepare for lesion evaluation and interpretation of the examination as a whole.
Our cases were divided into two main groups:
Group A: This group included 66 patients with cirrhotic liver 54 males (82%) and 12 females (18%). In this group certain lesions were found as follow:
11 lesions were diagnosed as RN/DN, 42 as HCC, 3 as focal confluent fibrosis, 7 as post TACE scar, 6 as post RFA scar, 5 as hemangiomas. The 11 lesions diagnosed as RN/DN were more accurately diagnosed by MRI than CT depending upon their signal intensity and enhancement pattern. MRI with different sequences can diagnose steatotoic RN (using IP/OP) as well as large DN (using DWI and depending upon the enhancement dynamics), these cases were managed by follow up except in patient with large DN as it was uncommon to have this size and need histopathologcal confirmation. 42lesions were diagnosed as HCC depending upon the different sequences which easily differentiate different types of HCC e.g fat containing HCC, HCC with fibrous or hemorrhagic components as well as DWI and superior lesion – to– liver contrast in triphasic MRI than in CT. Also MRI helped in diagnosis of portalvein thrombus and if this was bland or malignant thrombus depending upon DWI and enhancementdynamics of the thrombus which follow that of the main HCC lesion in malignant type. 3 lesions were diagnosed as focal confluent fibrosisdepending upon their signal intensity as well as delayed enhancement in triphasic study. No need for biopsy in these cases. 7 cases as post TACE scar and 6 cases as post RFA scar with no definite foci of activity mainly in DWI and triphasic study. 5 cases were diagnosed as hemangiomas depending on their signal intensity, T2 shine through in DWI and typical enhancement dynamics. FNAC wasdone for these casesto confirm the radiological diagnosis as it was uncommon to diagnose hemangiomas on top of cirrhotic liver.
Group B: This group included 62 patients with non cirrhotic liver 32 males (52%) and 30 females (48%).In this group different lesions were diagnosed as follow: 15 lesions were diagnosed as hemangiomas, 8 as FNH, 8 as cholangiocarcinoma, 21 as metastases, 1 as EHE , 2 as lymphoma, 2 as abscess, 1 as Budd Chiari, 1 as TS, 2 as fibrolamellar carcinoma and 2 as fatty infiltration. 15 cases were diagnosed as hemangiomas with typical signal intensity, T2 shine through in DWI as well as different enhancement patterns in triphasic study (flash filling hemangiomas ”6 cases”, hemangiomas with centripetal fillingin ”3 cases” and giant hemangiomas with central scar”3 cases”). 3 cases were limited non contrast study and depending upon the non contrast sequences and DWI in their diagnosis. MRI findings were enough for diagnosis with no need for biopsy in these cases. 8 cases were diagnosed as FNH, 6 of them were typical FNH with classic signal intensity and enhancement dynamics while 2 out of 8 cases were atypical FNH ,in one of them we used hepatobiliary specific contrast to confirm itsdiagnosis. The typical cases of FNH managed by follow up with no need for biopsy while in the two atypical cases further histopathological confirmation was needed. 8 cases were diagnosed as cholangiocarcinoma with the classic signal intensity and enhancement dynamics, 2 of them showed PV invasion.21 cases were diagnosed as metastases from different primaries, 4 of them refused the contrast administration and we depended upon history of primary with multiple hepatic lesions on top of non cirrhotic liver in their diagnosis. 14 out of 17 casesshowed delayed enhancing foci reflecting presence of fibrous components. 2 cases out of 17 showed cystic components and one case out of 17showed delayed enhancing foci as it was treated metastases. In these patients history of primary and presence of multiple hepatic lesions were enough for diagnosis of metastases without the need for biopsy. One case was diagnosed as EHE depending upon multiple hepatic, splenic sand nodal lesions with the classic enhancement dynamics (target sign) as well as overlying capsular retraction. Histopathological findings in this caseconfirmed the radiological diagnosis. 2 cases were diagnosed as lymphoma showed typical signal intensity, marked diffusion restriction with low ADC averaging 0.6x10-3 mm2/s. Histopathological findings confirmed the diagnosis of lymphoma.2 cases were diagnosed as hepatic abscesses, one of them was limited non contrast study due to low creatinine clearance and we depended upon the patient’s history, clinical data, aspiration form the abscess was diagnostic, marked diffusion restriction in DWI and adequate response to treatment. One case was diagnosed as Budd Chiari with the classic membrane in hepatic portion of IVC and on regular follow up developed NRH and finally the patient managed with TIPSS. One case was diagnosed as TS with classic features (renal angiomyolipoma, hepatic lipomas and hamartomas as well as brain subependymal tubers). 2 cases were diagnosed as fibrolamellar carcinoma with T2 hypointense scar that showed delayed enhancement. Histopathological findings confirmed the radiological diagnosis. 2 cases were diagnosed as fatty infiltration one of them was nodular in patient with ovarian cancer and suspecting hepatic deposits but MRI mainly IP/OP sequence was of a great help in diagnosis of focal fatty infiltration.