A. Gouliamos

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.

Magnetic resonance angiography compared to intra-arterial digital subtraction angiography in patients with subarachnoid haemorrhage

SummaryIn order to evaluate the sensitivity and specificity of magnetic resonance angiography (MRA) in spontaneous subarachnoid haemorrhage, 14 patients with recent haemorrhage verified by CT or lumbar puncture were investigated with both selective intra-arterial digital subtraction angiography (IA-DSA) and MRA by two independent teams, each having the same preangiographic information. The results were compared with each other and whenever possible (all positive cases except one) with those of surgical intervention. Seven patients were identified by MRA and IA-DSA as having a single aneurysm on the circle of Willis, 1 an aneurysm of the posterior inferior cerebellar artery 1 an aneurysm of the internal carotid artery (siphon) and 2 patients with two aneurysms on the circle of Willis. MRA and IA-DSA both failed to demonstrate aneurysms in 2 cases. Three patients had negative results on both methods and no surgical intervention was attempted. The aneurysms ranged from 0.3 to 1.5 cm in size. In most cases there was agreement between MRA and DSA, leading us to believe that, if the proper protocols are followed, MRA is a powerful alternative to other established methods in the detection of intracranial aneurysms. At this stage it will not replace IA-DSA prior to surgery, but the ability to obtain various projections using 3D MRA may improve surgical planning.

MR imaging of tuberculous vertebral osteomyelitis: pictorial review

Abstract Vertebral osteomyelitis is one of the most common manifestations of tuberculosis. Magnetic resonance imaging is considered the main imaging modality for the diagnosis, the demonstration of the extent of the disease, and follow-up studies. Vertebral destruction involving two consecutive levels with sparing of the intervertebral disc, disc herniation into the vertebral body, epidural involvement, and paraspinal abscess are the most common MRI findings suggestive of tuberculous vertebral osteomyelitis.

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.

Abdominal retained surgical sponges: CT appearance

Abstract. Retention of surgical sponges is rare. They cause either an aseptic reaction without significant symptoms or an exudative reaction which results in early but nonspecific symptoms. Computed tomography is very useful for recognition of retained sponges. The appearance of retained sponges is widely variable. Air trapping into a surgical sponge results in the spongiform pattern which is characteristic but unfortunately uncommon. A low-density, high-density, or complex mass is found in the majority of cases, but these patterns are not specific. Sometimes, a thin high-density capsule may be seen. Rim or internal calcification is a rare finding. Finally, a radiopaque marker is not a reliable sign. Differentiation from abscess and hematoma is sometimes difficult.

MRI of abdominal hydatid disease

Seventy hydatid cysts in 30 patients were studied with magnetic resonance imaging (MRI) and computed tomography (CT); all cases were confirmed surgically. MRI detected all cysts when confined to solid organs, whereas small-sized cysts (≤2 cm) may be missed when located in the peritoneal cavity. Hydatid cysts of less than 3 cm (noncomplicated) present no specific findings of hydatid disease. MRI findings suggesting hydatid disease demonstrate a relatively thick hydatid cyst wall, daughter cysts, and germinal membrane detachment. T2-weighted images proved to be superior to T1 or PD-weighted images in demonstrating hydatid cyst wall thickness, germinal membrane detachment, and daughter cysts. In all spin-echo sequences, the maternal cystic content presented much higher signal intensities than that of daughter cysts. This difference in signal intensity is more obvious in T2 weighted images, except in complicated, infected cases. CT proved to be superior to MRI in demonstrating wall calcifications.

CT and MRI of symptomatic spinal involvement by extramedullary haemopoiesis

Five cases of tumour-like extramedullary haemopoiesis (EH) causing spinal cord compression or back pain are reported. Three patients were suffering from thalassaemia major, one from sickle cell anaemia and one from thalassaemia intermedia. CT findings included soft tissue masses in the epidural space of the spinal canal, spinal cord displacement and involvement of the underlying bone. MRI studies showed masses compressing the spinal cord. On T1-weighted images there was a signal of slightly higher intensity compared to that of the adjacent marrow. CT suggested the diagnosis in four cases (in the fifth it was not performed), while MRI was positive in all five. There was good correlation between the MRI findings and the CT appearance of the EH masses. Our results suggest that MRI may eliminate the need for other diagnostic examinations in the investigation of patients with EH.

CT appearance of solitary and multiple cystic and cavitary lung lesions

Abstract Cystic and cavitary lung lesions constitute a spectrum of pulmonary diseases diagnosed in both children and adults. We reviewed the CT findings of the most common cystic and cavitary lung lesions and we defined useful morphological criteria that will help

MR imaging of complex tail-gut cysts

Retrorectal-cyst hamartomas (RCH) are rare developmental tail-gut cystic tumours of the retrorectal space, which occasionally undergo malignant transformation. We describe the magnetic resonance imaging (MRI) findings in two patients with RCH and in a third patient with unclassified sarcoma arising from a RCH. The RCH were hypointense or hyperintense on T1-weighted images and hyperintense on T2-weighted images; they did not enhance and they contained multiple septations. A solid component in the periphery of one cyst was markedly hypointense on T2-weighted images in keeping with fibrous material. The sarcoma arising from the wall of the RCH enhanced and was of intermediate signal intensity on all sequences. MR may help establish the diagnosis of RCH if an unenhanced cystic tumour is discovered in the retrorectal space and it can help detect those rare cases of malignant transformation of these developmental tumours.