Uneven hepatic iron and phosphorus distribution in beta-thalassemia

Ambu, Rossano; Crisponi, Guido; Sciot, Raf; Eyken, Pete Van; Parodo, Giuseppina; Ianneli, Sergio; Marongiu, Francesco; Silvagni, Roberta; Nurchi, Valeria Marina; Costa, Virgilio; Faa, Gavino; Desmet, Valeer

doi:10.1016/0168-8278(95)80060-3

Cited by 89 publications

(77 citation statements)

References 16 publications

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“…Our finding is in contrast with the previously described histological data (14,16,24). However, our study population is different, considering a homogenous and large cohort of TM patients.…”

Section: Discussioncontrasting

confidence: 99%

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Single region of interest versus multislice T2* MRI approach for the quantification of hepatic iron overload

Meloni

Luciani

Positano

et al. 2011

Magnetic Resonance Imaging

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Purpose: To evaluate the effectiveness of the single ROI approach for the detection of hepatic iron burden in thalassemia major (TM) patients in respect to a whole liver measurement. Materials and Methods:Five transverse hepatic slices were acquired by a T2* gradient-echo sequence in 101 TM patients and 20 healthy subjects. The T2* value was calculated in a single region of interest (ROI) defined in the medium-hepatic slice. Moreover, the T2* value was extracted on each of the eight ROIs defined in the functionally independent segments. The mean hepatic T2* value was calculated.Results: For patients, the mean T2* values over segments VII and VIII were significantly lower. This pattern was substantially preserved in the two groups identified considering the T2* normal cutoff. All segmental T2* values were correlated with the single ROI T2* value. After the application of a correction map based on T2* fluctuations in the healthy subjects, no significant differences were found in the segmental T2* values.Conclusion: Hepatic T2* variations are low and due to artifacts and measurement variability. The single ROI approach can be adopted in the clinical arena, taking care to avoid the susceptibility artifacts, occurring mainly in segments VII and VIII.

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Section: Discussioncontrasting

confidence: 99%

“…deposition in cirrhosis (14) and in hemochromatosis (16,24). Thus, iron content determined in a small liver sample could not absolutely represent the mean hepatic iron concentration.…”

Section: Discussionmentioning

confidence: 99%

Single region of interest versus multislice T2* MRI approach for the quantification of hepatic iron overload

Meloni

Luciani

Positano

et al. 2011

Magnetic Resonance Imaging

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“…Two published studies have reached different conclusions. In one study [3], performed by multiple large samples obtained from two postmortem thalassemia livers, a huge liver iron concentration variability was reported. In the other study [4], multiple large samples were obtained in six livers from liver transplantation.…”

Section: Discussionmentioning

confidence: 99%

“…Nowadays, only two validated noninvasive methods are available (MRI-R2 and R2*) [2] and liver biopsy continues to be the gold standard for hepatic iron determination. However, concern has been raised on the capability of the determination of iron concentration in a single hepatic biopsy sample to represent the entire parenchyma iron concentration [3,4]. For this reason, we conducted an in vivo prospective study to determine if iron concentration evaluated from a single biopsy specimen could be accurately reproduced by another independent biopsy sample of the same patient.…”

Section: Introductionmentioning

confidence: 99%

Reproducibility of liver iron concentration measured on a biopsy sample: A validation study in vivo

et al. 2014

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Determination of liver iron concentration is essential to predict iron related tissue damage and to guide chelation therapy. To assess the reliability of a single biopsy iron concentration determination in representing the whole liver iron concentration, we conducted a prospective study performing two immediately successive liver biopsies from 61 noncirrhotic, iron overloaded thalassemia patients, directing the needle to different direction from the same skin cut. The correlation among sample biopsies was determined by both regression analysis and the Bland-Altman method. The results showed that overall correlation between the two samples was high (Pearson's coefficient of correlation r 5 0.970, P < 0.0001; 95% CI 0.951-0.981; R 2 5 0.941). To evaluate if sample dimension had an impact on the analysis we analyzed separately biopsy couples were both sample gross weight were 1 mg dry weight (n 5 16) from the others [one or both had a specimen gross weight <1 mg dry weight (n 5 45)]. In the first case, correlation coefficient r was equal to 0.998 (P < 0.0001; 95% CI: 0.995-0.999; R 2 5 0.996) while in the latter was 0.960 (P < 0.0001; 95% CI: 0.928-0.977; R 2 5 0.921). In no instance second specimen prediction interval was outside the interval implying different prognostic and therapeutic decision if both liver samples gross weight were 1 mg dry weight. The Bland-Altman plot analysis showed the same trend observed using Pearson's correlation coefficient in the analyzed sample categories. Hepatic iron concentration determined in "good quality" biopsy specimen (i.e. sample gross weight 1 mg dry weight) is a reliable indicator of whole liver iron concentration.

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“…The minimum weight for an adequate liver sample for analysis remains uncertain; evidence has been provided both for thresholds of 0.4 mg dry weight [8,9] and for 1 mg dry weight [1,4,5]. Reports of variability in the hepatic iron concentration in different areas of the liver have generally been restricted to studies of cirrhotic livers [10][11][12]; data are lacking in patients with transfusional iron overload without cirrhosis. Even so, the close relationship observed between the hepatic iron concentration and total body iron stores [4] in transfused patients with thalassemia who were free of cirrhosis suggests that the extent of variability is limited.…”

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confidence: 99%

Reference method for measurement of the hepatic iron concentration

Brittenham

2015

American J Hematol

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What should be the reference method for measurement of the hepatic iron concentration? In this issue of the American Journal of Hematology, Urru and colleagues [1] present further evidence that, in patients with thalassemia major and transfusional iron overload, chemical measurement of the iron concentration in a desiccated liver-biopsy specimen obtained by percutaneous biopsy is highly reproducible, as judged by measurement in a successive specimen, provided that two conditions are met. The first condition is the absence of cirrhosis, defined in this study as Ishak scores [2] of 5 or 6, because, with cirrhosis, the iron distribution within the liver is no longer uniform. The second condition is that the liver-biopsy specimen is adequate, 1 mg dry weight; variability increases with smaller samples. No complications were observed with liver biopsy, extending the record of safety of liver biopsy in expert hands [3][4][5]. These results corroborate previous observations from these and other investigators [5][6][7] that support chemical measurement of the iron concentration in a liver-biopsy specimen as the reference standard for measurement of the hepatic iron concentration. Still, dissonance in the details must be acknowledged; no standard method for liver biopsy procedure, specimen processing and analysis has been established. The biopsy needle (cutting needle or Menghini needle with saline flushing), exposure to saline, formalin, and fixation solutions, use of iron-free containers, specimen processing (fresh or paraffin-embedded; methods of deparaffinization and of digestion), methods of analysis (colorimetric, atomic absorption spectroscopy, inductively coupled plasma mass spectroscopy), and other factors differ among published studies and potentially influence results [5,6]. Hepatic iron concentrations measured in deparaffinized samples were a mean of 23% greater than those in desiccated tissue from fresh liver specimens [6]. The minimum weight for an adequate liver sample for analysis remains uncertain; evidence has been provided both for thresholds of 0.4 mg dry weight [8,9] and for 1 mg dry weight [1,4,5]. Reports of variability in the hepatic iron concentration in different areas of the liver have generally been restricted to studies of cirrhotic livers [10][11][12]; data are lacking in patients with transfusional iron overload without cirrhosis. Even so, the close relationship observed between the hepatic iron concentration and total body iron stores [4] in transfused patients with thalassemia who were free of cirrhosis suggests that the extent of variability is limited.An alternative view of the reference method for measurement of the hepatic iron concentration is that magnetic resonance imaging (MRI), recommended in a variety of guidelines, has become the de facto technique. Nonetheless, since acceptance of the manuscript by Urru et al.[1] for publication, a painstaking systematic review and meta-analysis of this use of MRI has appeared, [13] concluding that "measurements of liver iron concentration by ...

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Uneven hepatic iron and phosphorus distribution in beta-thalassemia

Cited by 89 publications

References 16 publications

Single region of interest versus multislice T2* MRI approach for the quantification of hepatic iron overload

Single region of interest versus multislice T2* MRI approach for the quantification of hepatic iron overload

Reproducibility of liver iron concentration measured on a biopsy sample: A validation study in vivo

Reference method for measurement of the hepatic iron concentration

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