T2 Relaxometry of the Hippocampus at 3T

Bartlett, Philippa A.; Symms, Mark R.; Free, S. L.; Duncan, John S.

doi:10.3174/ajnr.a0505

Cited by 39 publications

(37 citation statements)

References 11 publications

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“…The fast spin echo sequence was part of an existing pharmaceutical protocol, which prompted us to test its performance. The estimated higher T 2 values that we show with FSEs in phantoms and cartilage is consistent with the literature (6). Utilizing the student's t test, the mean relaxation time of fast spin echo with 8 echo train lengths is significantly higher than fast spin echo with 4 echo train lengths in all tissues.…”

Section: Discussionsupporting

confidence: 78%

“…Insufficient sampling of the T 2 decay curve, RF and static field inhomogeneities, stimulated echoes, and T1 effects can all attribute to the incorrect quantitation of in vivo relaxation times (5). Currently the most commonly used T 2 quantification sequences are spin-echo (SE) and fast spin-echo (FSE) sequences (6). Several pulse sequences have been developed in the determination of T 2 relaxation times in musculoskeletal system.…”

Section: Introductionmentioning

confidence: 99%

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A comparative study at 3 T of sequence dependence of T2 quantitation in the knee

Pai

Majumdar

2008

Magnetic Resonance Imaging

105

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Objective-T 2 mapping has been used widely in detecting cartilage degeneration in osteoarthritis. Several scanning sequences have been developed in the determination of T 2 relaxation times of tissues. However, the derivation of these times may vary from sequence to sequence. This study seeks to evaluate the sequence dependent differences in T 2 quantitation of cartilage, muscle, fat and bone marrow in the knee joint at 3 Tesla.Methods-Three commercial phantoms and ten healthy volunteers were studied using 3T MR. T 2 relaxation times of the phantoms, cartilage, muscle, subcutaneous fat, and marrow were derived using spin echo (SE), multi-echo spin echo (MESE), fast spin echo (FSE) with varying echo train length (ETL), spiral, and spoiler gradient (SPGR) sequences. The differences between these times were then evaluated using a student's t-test. In addition, the SNR efficiency and coefficient of variation of T 2 from each sequence were calculated.Results-The average T 2 relaxation time was 36.38 ± 5.76 ms in cartilage and 34.08 ± 6.55 ms in muscle, ranging from 27 to 45 ms in both tissues. The times for subcutaneous fat and marrow were longer and more varying, ranging from 41 to 143 ms and 42 to 160 ms, respectively. In FSE acquisition, relaxation time significantly increases as ETL increases (P < 0.05). In cartilage, the SE acquisition yields the lowest T 2 values (27.52 ± 3.10 ms), which is significantly lower than those obtained from other sequences (P < 0.002). T 2 values obtained from spiral acquisition (38.27 ± 6.45 ms) were higher than those obtained from MESE (34.35 ± 5.62 ms) and SPGR acquisition (31.64 ± 4.53 ms). These differences, however, were not significant (P > 0.05).Conclusion-T 2 quantification can be a valuable tool for the diagnosis of degenerative disease. Several different sequences exist to quantify the relaxation times of tissues. Sequences range in scan time, SNR efficiency, reproducibility, and 2D or 3D mapping. However, when choosing a sequence for quantitation, it is important to realize that several factors affect the measured T 2 relaxation time.

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Section: Discussionsupporting

confidence: 78%

Section: Introductionmentioning

confidence: 99%

A comparative study at 3 T of sequence dependence of T2 quantitation in the knee

Pai

Majumdar

2008

Magnetic Resonance Imaging

105

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“…As mentioned earlier, the relaxometric studies were used to determine some fluid components of body fluids or organs [5][6][7][8][9][10][11]. The relaxometric determination of such a component may be explained by Eqs.…”

Section: Determination Of the Total Relaxivitiesmentioning

confidence: 99%

“…Accordingly, the increase in relaxation rate per unit concentration of total material content of a fluid is called total relaxivity. The relaxometric methods have been used to study relaxation changes in various fluids and organs [5][6][7][8][9][10][11]. MR relaxometry was used for estimating bone marrow iron, myocardial iron overload, hepatic iron content, and liver iron concentration [5,[9][10][11].…”

Section: Introductionmentioning

confidence: 99%

Total Relaxivities of Material Content in Various Cysts and Ameloblastoma: Implications for Discriminating Different Fluids

Yilmaz

Güner

Erol

2009

Biol Trace Elem Res

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Nuclear magnetic resonance T(1) and T(2) relaxivities (r(1) and r(2)) exhibit efficiency of a material to alter the relaxation rates (1/T(1) and 1/T(2)), and they are being used for diagnostic purposes. The determination of total relaxivities (r(1t) and r(2t)) of cystic fluid content and ameloblastoma may therefore be useful for discriminative purposes. In order to determine what makes total relaxivities of hemorrhagic cysts, four sets of tubes containing pooled cyst were doped with increasing concentrations of iron, copper, albumin, and gamma-globulins. These sets were replaced in a phantom together with six individual cysts and one ameloblastoma. The relaxation times were measured by magnetic resonance imaging operating at 1.5 T. The relaxivities of individual ions and proteins were determined from the slope of the relation between relaxation rates and concentration, while total relaxivities were determined by using the increases in relaxation rates and material content of cystic fluid (MC). Iron, copper, albumin, and gamma-globulins were found to be the sources of r(1t) and r(2t). Each of r(1t), r(2t), r(1t)MC, r(2t)MC, and r(2t)/r(1t) are distinctive parameters for each cystic category and ameloblastoma. Except for MC, the parameters measured for ameloblastoma are significantly smaller than those of cysts. The similarity of the present results to those used in clinical applications suggests that each of r(1t), r(2t), r(1t)MC, r(2t)MC, and r(2t)/r(1t) has an ability to discriminate various fluids and masses. The present work also suggests that r(1t)MC, r(2t)MC, and r(2t)/r(1t) can be determined in vivo.

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“…MR relaxometry has been demonstrated to be a useful technique for estimating bone marrow iron, myocardial iron overload, hepatic iron content and liver iron concentrations [5][6][7][8]. Relaxometric determination of bone marrow changes in anorexia nervosa and also relaxometric studies of some organs such as the liver, spleen, and brain have already been made [9][10][11]. The estimation of iron in those tissues was suggested to be useful for early diagnosis of iron disorder diseases [6].…”

Section: Introductionmentioning

confidence: 99%

MR Proton Relaxivities of Some Ions, Albumin, and Cholesterol Added to Odontogenic Jaw Cysts

Yilmaz

Güner

2008

Biol Trace Elem Res

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The relaxation rates (1/T(1) and 1/T(2)) in cysts have already been analyzed in terms of materials such as albumin, cholesterol, manganese, iron, and copper. However, the relaxivities of these materials have not been determined yet. In this work, five sets containing the ions, albumin, and cholesterol were prepared by addition of increasing concentration of one material to each set. The relaxation times in these sets were measured by MRI, and the relaxation rates were fitted versus concentrations. The slopes of the fits were used as relaxivities. The (r(1), r(2)) values of manganese, iron, and copper in mM(-1) s(-1), and those of albumin and cholesterol in (g/dl)(-1) s(-1) were found to be (32.64, 89.77), (0.31, 1.19), (0.5, 1.479), (0.01, 0.066) and (0.03, 0.458), respectively. The r(2)/r(1) ratio ranged from 2.75 to 15.27. Manganese is an efficient relaxer, but iron and copper are poor ones. Albumin and cholesterol are efficient relaxers for only T(2). The contribution of water associated with native manganese of the cystic fluid to T(1) was 0.268 s(-1), whereas those of water associated with native manganese, albumin, cholesterol, and iron to T(2) were 0.736, 0.185, 0.092, and 0.076 s(-1), respectively. The other contributions were much smaller than 0.076 s(-1). Manganese is most likely the compound altering T(1)-weighted images between different jaw cysts, whereas manganese and albumin are most likely the compounds altering the T(2)-weighted images. Present data suggest that such alterations may be used to separate jaw cysts from other jaw masses. The high r(2)/r(1) suggests that T(2) is a more convenient parameter than T(1) for diagnostic use.

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T2 Relaxometry of the Hippocampus at 3T

Cited by 39 publications

References 11 publications

A comparative study at 3 T of sequence dependence of T2 quantitation in the knee

A comparative study at 3 T of sequence dependence of T2 quantitation in the knee

Total Relaxivities of Material Content in Various Cysts and Ameloblastoma: Implications for Discriminating Different Fluids

MR Proton Relaxivities of Some Ions, Albumin, and Cholesterol Added to Odontogenic Jaw Cysts

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