Olympia Papakonstantinou

Assessment of liver iron overload by T2-Quantitative magnetic resonance imaging: Correlation of T2-QMRI measurements with serum ferritin concentration and histologic grading of siderosis

PURPOSE To correlate hepatic 1/T2 values obtained by means of a T2-Quantitative MRI (T2-QMRI) technique with three widely applied methods for the evaluation of hemosiderosis, i.e., (a) liver iron concentrations (LFeC) (b) serum ferritin (SF), and (c) histologic grading of siderosis. The impact of coexisting hepatitis was also considered. T2-QMRI measurements were compared with signal intensity (SI) ratio measurements on conventional SE images. MATERIALS AND METHODS Liver T2 relaxation times were calculated in 40 thalassemic patients, on a 0.5 T magnetic resonance imaging system using a multiple spin-echo sequence with parameters: TR = 2500 ms, TE = 12 ms in 20 symmetrically repeatable echoes. RESULTS (a) 1/T2 values were well correlated (r = 0.97) with liver iron concentrations, which ranged from 2.32 to 18.0 mg/g dry weight (normal < 1.6 mg/g). (b) 1/T2 values were also correlated with serum ferritin levels (r = 0.84). At various 1/T2 values, serum ferritin levels were higher for the anti-HCV(+) patients than the anti-HCV(-) ones. (c) T2 values corresponding to successive grades of siderosis presented statistically significant differences. (d) SI ratio measurement assigned less statistically significant results, as compared to T2 values. CONCLUSION T2-QMRI measurement of T2 relaxation time is more accurate than SI ratios in evaluating liver iron overload. It is particularly useful for hemosiderotic patients with coexisting hepatitis since, in this case, serum ferritin is not considered a reliable index of hemosiderosis.

The pancreas in β-thalassemia major: MR imaging features and correlation with iron stores and glucose disturbunces

The study aims at describing the MR features of pancreas in beta-thalassemia major, investigating the relations between MR findings and glucose disturbances and between hepatic and pancreatic siderosis. Signal intensity ratios of the pancreas and liver to right paraspinous muscle (P/M, L/M) were retrospectively assessed on abdominal MR imaging studies of 31 transfusion-dependent patients with beta-thalassemia major undergoing quantification of hepatic siderosis and 10 healthy controls, using T1- (120/4/90), intermediate in and out of phase - (120/2.7, 4/20), and T2*-(120/15/20) weighted GRE sequences. Using the signal drop of the liver and pancreas on opposed phase images, we recorded serum ferritin and results of oral glucose tolerance test (OGTT). Decreased L/M and P/M on at least the T2* sequence were noticed in 31/31 and 30/31 patients, respectively, but no correlation between P/M and L/M was found. Patients with pathologic OGTT displayed a higher degree of hepatic siderosis (p < 0.04) and signal drop of pancreas on opposed phase imaging (p < 0.025), implying fatty replacement of pancreas. P/M was neither correlated with glucose disturbances nor serum ferritin. Iron deposition in the pancreas cannot be predicted by the degree of hepatic siderosis in beta-thalassemia major. Fatty replacement of the pancreas is common and may be associated with glucose disturbances.

Assessment of iron distribution between liver, spleen, pancreas, bone marrow, and myocardium by means of R2 relaxometry with MRI in patients with β-thalassemia major

To investigate the correlation between the degree of hepatic, splenic, pancreatic, vertebral bone marrow (VBM), and myocardial siderosis, as expressed by relaxation rate (R2 = 1/T2) values, in patients with thalassemia.

Quantification of liver iron overload by T2 quantitative magnetic resonance imaging in thalassemia: impact of chronic hepatitis C on measurements.

PURPOSE Measurement of liver T2 values seems to be an accurate and sensitive magnetic resonance imaging (MRI) method for the quantification of liver hemosiderosis in multiple transfused patients with thalassemia. Because many of these patients have coexistent chronic hepatitis C virus (HCV) infection, the effect of inflammatory changes on liver T2 values was assessed. MATERIALS AND METHODS Liver MRI studies of 35 HCV+ and 17 HCV- patients with beta-thalassemia, 9 HCV+ patients without thalassemia, and 10 healthy controls of the same age range (13 to 32 years) were reviewed. Iron status was assessed by serum ferritin in all patients, and determination of liver iron concentration (LIC) was available in 16 HCV+ patients with thalassemia. Histologic activity index (HAI) and grades of siderosis were evaluated in all HCV+ patients with thalassemia. RESULTS Patients with thalassemia had significantly lower T2 values (P < 0.0001) than subjects without thalassemia, whereas no difference existed between HCV+ patients without thalassemia and healthy controls. In HCV+ patients, LIC correlated more nearly with T2 values (r = 0.93) than with serum ferritin (r = 0.73). T2 values were not influenced by HAI score or fibrosis. CONCLUSION Liver T2 values were found to be more accurate than serum ferritin in predicting liver iron overload and were not influenced by the presence of chronic hepatitis C. Therefore, MRI could serve as a noninvasive alternative to liver biopsy for the quantification of hemosiderosis in HCV+ patients with thalassemia.

Myocardial and liver iron status using a fast T*2 quantitative MRI (T*2qMRI) technique.

This work demonstrates the use of a fast and precise methodology for evaluating myocardial and liver iron status in multitransfused thalassemic patients by means of a fast T  2* quantitative MRI (T  2* qMRI) technique. Myocardial and liver T  2* values were calculated in 48 thalassemic patients and 21 normal subjects on a 1.5T MRI system using a breath‐hold 2D single‐slice multiecho gradient‐echo (MEGRE) sequence (16 echoes, TR/TE1/TE16/FA = 160/2.7/37.65 ms/25°). No ECG gating was used. Myocardial T  2* , liver T  2* , and myocardial to muscle (CR/MS) and liver to muscle (LV/MS) T  2* ratios were correlated with serum ferritin concentration (SFC) levels for all patients. Significant differences in myocardial and liver mean T  2* , CR/MS, and LV/MS T  2* values between patients and normal subjects were found (P < 0.0005). Differences in paraspinous muscle mean T  2* values between patients and normal subjects were not significant. Myocardial T  2* and CR/MS T  2* values were not correlated with SFC levels. Liver T  2* and LV/MS T  2* values were significantly correlated with SFC (r = 0.540, P < 0.0005). Myocardial T  2* and CR/MS T  2* values were not correlated with either liver T  2* or LV/MS T  2* values, respectively. We conclude that myocardial and liver iron deposition can be evaluated using the fast non‐ECG‐gated T  2* qMRI technique. Magn Reson Med 57:742–753, 2007.

Adrenal glands in beta-thalassemia major: magnetic resonance (MR) imaging features and correlation with iron stores.

This study aimed at describing the magnetic resonance (MR) imaging features of the adrenal glands in beta-thalassemic patients and at investigating the relation between adrenal and hepatic siderosis. Adrenal signal intensity (SI) was retrospectively assessed on abdominal MR studies of 35 patients with beta-thalassemia major undergoing quantification of hepatic siderosis and 12 healthy controls, using T1- (120/4/90), intermediate - (120/4/20), and T2*- (120/15/20) weighted GRE sequences. Adrenal SI was graded as grade 0 (normal SI on all sequences), grade 1 (hypointensity on T2* alone), or grade 2 (hypointensity on at least T2*). Adrenal size was measured in the thalassemic patients and compared with normative data. Liver-to-muscle (L/M) SI ratios, expressing hepatic siderosis, were estimated on each sequence. Serum ferritin levels were recorded. Adrenal hypointensity (grades 1 and 2) was noted in 24/35 (68.6%) patients. L/M ratios correlated significantly with adrenal SI in all sequences. Patients with grade 1 and grade 2 adrenal SI had significantly decreased L/M ratios compared with grade 0. Serum ferritin correlated significantly with L/M values but not with adrenal SI. Adrenal size was within normal limits. Diffuse hypointensity in normal-sized adrenals is a common MR finding in beta-thalassemic patients and correlates with the degree of hepatic siderosis.

Assessment of the progression of haemophilic arthropathy in children

Summary.  Arthropathy is considered as an irreversible and progressive complication in patients with haemophilia, even in children on prophylaxis. To estimate the progression of haemophilic arthropathy, 85 joints of 24 boys with severe (n = 18) and moderate (n = 6) haemophilia (A: 22, B: 2) were investigated with clinical examination, X‐rays and magnetic resonance imaging (MRI) at two time periods (time 0 and 1). Patients’ age at time 0 was 10.5 ± 3.6 years and time elapsed to time 1 was 3.8 ± 1.4 years. At time 0: all investigated joints had more than three bleeds. Sixteen boys were on secondary prophylaxis for 5.4 ± 2.8 years. Clinical score (a modification of World Federation of Haemophilia’s scale): 2.0 ± 3.6, X‐ray score (Pettersson): 2.1 ± 2.8, MRI score (Denver): 4.5 ± 3.8. After the first evaluation, prophylaxis was intensified in 11 children and initiated in four. At time 1: clinical score: 1.5 ± 3.1, X‐ray: 1.7 ± 2.7, MRI score: 5.1 ± 4.1. On average, the clinical and X‐ray scores showed a significant improvement (26% and 40% of the joints respectively, P < 0.01) and the number of haemarthroses evidenced a threefold reduction from time 0 to 1 (P < 0.01), findings that could be associated with the modification of prophylaxis after time 0. MRI findings showed deterioration in 34% of the joints. Conversely, 14 joints (16.5%) with mild or moderate synovitis without cartilage degradation at time 0 showed an improvement at time 1. The information carried by the three scales could be divided into information shared by the three scores and information specific to each score, thus giving a more complete picture of joint damage caused by bleedings.

MR imaging of pituitary hyperplasia in a child with growth arrest and primary hypothyroidism

Abstract. Magnetic resonance imaging of pituitary hyperplasia has been rarely described in children with primary hypothyroidism. We report a case of pituitary hyperplasia in a child presented with significant growth arrest and laboratory evidence of hypothyroidism. Magnetic resonance imaging revealed symmetrical pituitary enlargement simulating macroadenoma. After thyroid hormone replacement therapy, the childs height increased and pituitary enlargement regressed to normal. Awareness of MRI appearance of pituitary hyperplasia in children with laboratory evidence of hypothyroidism might avoid misdiagnosis for pituitary tumor, which may also manifest as growth disorder, obviating unnecessary surgery.

Use of fat suppression in R2 relaxometry with MRI for the quantification of tissue iron overload in beta-thalassemic patients

PURPOSE To assess the performance and results of R(2) relaxometry using a fat-suppressed (FS) multiecho sequence and compare these to conventional R(2) relaxometry in estimating tissue iron overload. MATERIALS AND METHODS Relaxation rate values (R(2)=1/T2) of the liver, spleen, pancreas and vertebral bone marrow (VBM) were estimated in 21 patients with β-thalassemia major, using a respiratory-triggered 16-echo Carr-Purcell-Meiboom-Gill (CPMG) spin-echo sequence before (R(2)) and after (R(2) FS) the application of chemically selective fat suppression. RESULTS Hepatic and splenic R(2) FS values correlated with respective R(2) values (r=0.98 and r=0.96, P<.001), whereas correlations between R(2) FS and R(2) values for pancreas and VBM were not statistically significant. Bland-Altman plots show disagreement between R(2) and R(2) FS values, particularly for pancreas and VBM. Hepatic, pancreatic and VBM R(2) FS values correlated with serum ferritin (r=0.88, P<.001; r=0.51, P<.003; and r=0.75, P<.002, respectively). Hepatic R(2) FS values correlated with splenic R(2) FS (r=0.77, P<.03), pancreatic R(2) FS (r=0.61, P<.006) and VBM R(2) FS values (r=0.70, P<.001), whereas pancreatic R(2) FS values correlated also with VMB R(2) FS values. On the contrary, among the R(2) values of the above tissues, obtained without fat suppression, only hepatic R(2) values correlated with serum ferritin, whereas no correlation was documented between hepatic and pancreatic or VBM R(2) values. The application of fat suppression did not improve breathing or flow artifacts. CONCLUSION Application of fat suppression in the standard CPMG sequence improved the capability of MRI in noninvasive quantification of iron, particularly in lipid-rich tissues, such as vertebral bone marrow (VBM) and pancreas.

Investigative MR Cholangiopancreatography for Primary Sclerosing Cholangitis-type Lesions in Children With IBD

Objectives: The aim of the study was to estimate the frequency of primary sclerosing cholangitis (PSC)–type lesions in children with inflammatory bowel disease (IBD) by means of magnetic resonance cholangiopancreatography (MRCP), and to investigate the association between a series of easily applicable data on the one hand and the presentation of such lesions at MRCP on the other hand. Methods: Collected demographic, laboratory, and magnetic resonance enterography data from the records of 73 children with IBD were cross-sectionally related to the MRCP-based diagnosis. Results: Around the time of MRCP, the distribution of IBD subtypes was 64.4%, 24.7%, and 11% for Crohn disease, indeterminate colitis, and ulcerative colitis, respectively. A total of 11 patients (15.1%) were identified with PSC-type lesions. Demographic and magnetic resonance enterography data were unrelated to the MRCP outcome. Biochemical abnormalities were of low prevalence (<50%) among patients with PSC. The abnormality prevalences of aspartate transaminase, alanine transaminase, and &ggr;-glutamyl transferase were significantly higher in the PSC group, both at initial diagnosis of IBD and at the time of MRCP. Less-consistent results were documented for bilirubin and alkaline phosphatase, especially at initial diagnosis of IBD. Conclusions: The abnormality prevalences of aspartate transaminase, alanine transaminase, and &ggr;-glutamyl transferase were significantly higher in the PSC group. Nevertheless, PSC-type lesions frequently occur in pediatric IBD, even if the biochemical profile is hardly indicative of this probability.