T2 Relaxation Values Research Articles

Integrity of articular cartilage on T2 mapping associated with meniscal signal change

Objective The purpose of this study was to investigate the relationship between T2 relaxation values (T2 RVs) within the superficial zone of articular cartilage and different types of meniscal degeneration/tear. Materials and methods A review of 310 consecutive knee MRIs which included an 8 echo T2 relaxation sequence, in patients referred for standard clinical indications, was performed independently and in blinded fashion by 2 observers. The posterior horns of the medial and lateral menisci were each evaluated and divided into 4 subgroups: Normal (control), Grade I/II meniscal signal, Grade III meniscal signal-simple tear (Grade III-S), and Grade III meniscal signal-complex tear (Grade III-C). After exclusion criteria were applied, the medial meniscal group consisted of 65 controls and 133 patients, while the lateral meniscal group consisted of 143 controls and 55 patients. T2 RVs were measured by an observer blinded to the clinical history and MRI grading. Measurements were obtained over the superficial zone of femoral and tibial articular cartilage adjacent to the center of the posterior horn of each meniscus to ensure consistency between measurements. Analysis of covariance adjusting for age and gender was used to compare T2 RVs between patients and controls. Results T2 RVs were significantly increased in patients with Grade III-C meniscal tears compared to controls over the medial tibial plateau (MTP; p = 0.0001) and lateral tibial plateau (LTP; p = 0.0008). T2 RVs were not increased in patients with Grade III-C meniscal tears over the medial femoral condyle (MFC; p = 0.11) or lateral femoral condyle (LFC; p = 0.99). Grade I/II meniscal signal was not associated with elevated T2 RVs over the MFC ( p = 0.15), LFC ( p = 0.69), MTP ( p = 0.42), or LTP ( p = 0.50). Grade III-S meniscal signal was not associated with elevated T2 RVs over the MFC ( p = 0.54), LFC ( p = 0.43), MTP ( p = 0.30), or LTP ( p = 0.38). Conclusion Grade III-C meniscal tears are associated with elevated T2 RVs in adjacent tibial articular cartilage. The results may have an impact on prognostication and treatment in order to delay or prevent the onset of osteoarthritis.

Basal Ganglia MR Relaxometry in Obsessive-Compulsive Disorder: T2 Depends Upon Age of Symptom Onset

Dysfunction in circuits linking frontal cortex and basal ganglia (BG) is strongly implicated in obsessive-compulsive disorder (OCD). On MRI studies, neuropsychiatric disorders with known BG pathology have abnormally short T2 relaxation values (a putative biomarker of elevated iron) in this region. We asked if BG T2 values are abnormal in OCD. We measured volume and T2 and T1 relaxation rates in BG of 32 adults with OCD and 33 matched controls. There were no group differences in volume or T1 values in caudate, putamen, or globus pallidus (GP). The OCD group had lower T2 values (suggesting higher iron content) in the right GP, with a trend in the same direction for the left GP. This effect was driven by patients whose OCD symptoms began from around adolescence to early adulthood. The results suggest a possible relationship between age of OCD onset and iron deposition in the basal ganglia.

Brain Injury in Autonomic, Emotional, and Cognitive Regulatory Areas in Patients With Heart Failure

Background Heart failure (HF) is accompanied by autonomic, emotional, and cognitive deficits, indicating brain alterations. Reduced gray matter volume and isolated white matter infarcts occur in HF, but the extent of damage is unclear. Using magnetic resonance T2 relaxometry, we evaluated the extent of injury across the entire brain in HF. Methods and Results Proton-density and T2-weighted images were acquired from 13 HF (age 54.6 ± 8.3 years; 69% male, left ventricular ejection fraction 0.28 ± 0.07) and 49 controls (50.6 ± 7.3 years, 59% male). Whole brain maps of T2 relaxation times were compared at each voxel between groups using analysis of covariance (covariates: age and gender). Higher T2 relaxation values, indicating injured brain areas ( P < .005), emerged in sites that control autonomic, analgesic, emotional, and cognitive functions (hypothalamus, raphé magnus, cerebellar cortex, deep nuclei and vermis; temporal, parietal, prefrontal, occipital, insular, cingulate, and ventral frontal cortices; corpus callosum; anterior thalamus; caudate nuclei; anterior fornix and hippocampus). No brain areas showed higher T2 values in control vs. HF subjects. Conclusions Brain structural injury emerged in areas involved in autonomic, pain, mood, language, and cognitive function in HF patients. Comorbid conditions accompanying HF may result from neural injury associated with the syndrome.

Can T2 relaxation values and color maps be used to detect chondral damage utilizing subchondral bone marrow edema as a marker?

This study aimed to investigate whether a commercially available time-efficient T2 mapping sequence will demonstrate findings of articular cartilage degeneration based on T2 relaxation values (RV) and color maps, using subchondral bone marrow edema (BME) as a marker for chondral damage. The patient group consisted of 88 subjects who underwent knee magnetic resonance imaging at 1.5 T who had subchondral BME evident on fat-suppressed T2-weighted sequences. The control group was comprised of 60 subjects with no evidence of subchondral BME. A commercially available eight echo T2 relaxation sequence (acquisition time 8:36 min) was used to construct a T2 color map and to determine T2 RVs. T2 RVs were determined on cartilage overlying subchondral BME in patients and in eight pre-determined anatomical regions in controls. T2 color maps in the patient and control groups were analyzed for degree of color stratification (presence = two or more colors) at the same anatomic site as that used for T2 RV determination. T2 RVs were significantly increased in patients compared to controls for the medial femoral condyle (MF; p < 0.01), medial patellar facet (MP; p < 0.01), lateral patellar facet (LP; p < 0.01), lateral femoral condyle (LF; p < 0.01) and lateral tibial plateau (LT; p < 0.01). Loss of color stratification was noted in patients compared to controls in the medial tibial plateau (MT; p = 0.01), LF (p < 0.01), and LT (p < 0.01). In the patient group, increase in T2 RVs was associated with corresponding decrease in color stratification in MF (p < 0.01), MT (p < 0.01), MP (p < 0.01), medial femoral trochlear groove (p = 0.02), and lateral femoral trochlear groove (p < 0.01). Subchondral BME was associated with an increase in adjacent articular cartilage T2 RVs at some sites. Also, elevated T2 RVs were associated with loss of color stratification.

Neural alterations associated with anxiety symptoms in obstructive sleep apnea syndrome

Neuropsychological comorbidities, including anxiety symptoms, accompany obstructive sleep apnea (OSA); structural and functional brain alterations also occur in the syndrome. The objective was to determine whether OSA patients expressing anxiety symptoms show injury in specific brain sites. Magnetic resonance T2-relaxometry was performed in 46 OSA and 66 control subjects. Anxiety symptoms were evaluated using the Beck Anxiety Inventory (BAI); subjects with BAI scores >9 were classified anxious. Whole brain T2-relaxation maps were compared between anxious and nonanxious groups using analysis of covariance (covariates, age and gender). Sixteen OSA and seven control subjects showed anxiety symptoms, and 30 OSA and 59 controls were nonanxious. Significantly higher T2-relaxation values, indicating tissue injury, appeared in anxious OSA versus nonanxious OSA subjects in subgenu, anterior, and mid-cingulate, ventral medial prefrontal and bilateral insular cortices, hippocampus extending to amygdala and temporal, and bilateral parietal cortices. Brain injury emerged in anxious OSA versus nonanxious controls in bilateral insular cortices, caudate nuclei, anterior fornix, anterior thalamus, internal capsule, mid-hippocampus, dorsotemporal, dorsofrontal, ventral medial prefrontal, and parietal cortices. Anxious OSA subjects showed injury in brain areas regulating emotion, with several regions lying outside structures affected by OSA alone, suggesting additional injurious processes in anxious OSA subjects.

Cognitive Test Performance and Brain Pathology

Cognitive impairment, assessed using paper-and-pencil tests, occurs with multiple syndromes, including heart failure; however, relationships between test performance and brain injury are unclear. To determine the extent of brain injury assessed by magnetic resonance T2 relaxometry procedures in a mixed sample with cognitive impairment as measured by the Mini-Mental State Examination, Trailmaking Test parts A (TMT-A) and B (TMT-B), and the Watson Clock-Drawing Test (CDT). A comparative design was used with a convenience sample of 66 participants (age 48.2 +/- 8.4 years, 41 males, 52 right-handed). Normal and abnormal performances on cognitive tests were compared using T2 relaxation values across the brain (p < .005). Fifty-four of the participants were healthy, and 12 had heart failure (New York Heart Association classes II-III, left ventricular ejection fraction <0.40). All participants scored normally on the Mini-Mental State Examination; thus, this test was excluded from further analysis. Abnormal cognitive scores were found in 14-20% of the participants, with significant brain injury appearing in participants with abnormal test scores. Injured structures included frontal, temporal, parietal, insular, and cingulate cortices; corpus callosum; and caudate. The CDT results showed the greatest extent of structural injury. The TMT-A test demonstrated relationships to specific injury sites, whereas the TMT-B showed relationships only to isolated areas of damage. The findings suggest that paper-and-pencil cognitive tests relate to injury in brain structures, with CDT values relating to the greatest extent of injury. Specific damage sites may correlate with unique tests, such as TMT-A. Specialized tests should be developed that would indicate neural injury in specific areas.

Quantitative magnetic resonance techniques in the evaluation of intracranial tuberculomas

To evaluate intracranial tuberculomas using quantitative magnetic resonance (MR) techniques such as T2 relaxometry, magnetization transfer (MT), and diffusion-weighted imaging (DWI). Thirty-three patients with intracranial tuberculomas (histologically confirmed in 22) were evaluated using proton density/T2-weighted, T1-weighted (with and without MT), and echo-planar diffusion-weighted imaging sequences. T2 relaxation times, MT ratios (MTR), and apparent diffusion coefficient (ADC) values were calculated from the center of the lesion, the periphery, perilesional edema, and contralateral normal white matter. The mean and standard deviation values of each variable were calculated and correlated using Pearson's test (P = 0.05). The measured mean values of T2 relaxation time, MTR, and ADC in the center of lesions were 155.5 ms, 14.1, and 1.27 x 10(-3) mm(2)/s, respectively, compared to 117 ms, 23.72, and 0.74 x 10(-3) mm(2)/s in normal white matter, and a T2 relaxation time of 187.45 ms in normal gray matter. Significant inverse correlations were noted between T2 relaxation values and MTR (P<0.001) and between MTR and ADC (P = 0.046). Significant positive correlation was seen between T2 relaxation and ADC values (P = 0.03). Intracranial tuberculomas are characterized by relatively short T2 relaxation times (compared to normal gray matter), decreased MTR, and mostly no restriction of diffusion. A combination of these quantitative parameters could be of help in the noninvasive diagnosis of tuberculomas.

Combined T1‐T2 mapping of human femoro‐tibial cartilage with turbo‐mixed imaging at 1.5T

To evaluate the influence of Gd-DTPA on cartilage T2 mapping using turbo-mixed (tMIX) imaging, and to show the possible usefulness of the tMIX technique for simultaneously acquiring T1 and T2 information in cartilage. Twenty volunteers underwent MRI of the knee using the tMIX sequence before and after gadolinium administration. T1 and T2 maps were calculated. The mean T1 was determined on the pre- and postcontrast T1 maps. T2 relaxation values before and after gadolinium administration were statistically analyzed. The obtained relaxation values are in correspondence with previously published data. The mean T1 before gadolinium administration was 449 msec +/- 34.2 msec (SD), and after gadolinium administration it was 357 msec +/- 55.8 msec (SD). The postcontrast T1 relaxation range was 221.5-572.8 msec. The mean T2 of the precontrast T2 maps was 34.2 msec +/- 3.1 msec (SD), and the mean T2 of the postcontrast T2 maps was 32.5 msec +/- 3.1 msec (SD). These are statistically significant different values. A correction for the postcontrast T2 values, using a back-calculation algorithm, yielded a 98% correlation with the precontrast T2 values. The absolute difference of pre- and postcontrast T2 is very small and is ruled out using the back-calculation algorithm. Combined T1-T2 tMIX cartilage mapping is a valuable alternative for separate T1 and T2 cartilage mapping.

Cardiac magnetic resonance imaging abnormalities in systemic lupus erythematosus: a preliminary report

The purpose of this prospective, pilot study was to determine whether differences in myocardial T2 relaxivity can be identified among active systemic lupus erythematosus (SLE) patients with clinically suspected SLE myocarditis, other active SLE patients, inactive SLE patients and age and gender matched controls. Eleven consecutive female patients (six with active SLE and five with inactive SLE), and five age, gender and race matched healthy controls underwent imaging with echocardiography and cardiac magnetic resonance imaging (MRI). Echocardiographic measurements included left ventricular end diastolic (LVEDV) and end systolic volumes (LVESV), and mass (LVM) (all indexed to body mass); ejection fraction and cardiac output. The cardiac MRI measurement was the T2 relaxation time (an index of soft tissue signal, with higher levels suggestive of increased tissue water content). Patients with active SLE had significantly higher LVEDV and LVM than inactive SLE patients and healthy controls, and significantly larger LVESV than healthy controls. Myocardial T2 relaxation times were significantly higher in patients with active SLE compared to those with inactive SLE and to healthy controls, and remained higher even after excluding the two active SLE patients who had clinical myocarditis. The four active SLE patients who underwent repeat cardiac imaging studies after clinical improvement showed normalization of these myocardial abnormalities. The conclusion was that active SLE patients demonstrate abnormalities in myocardial structure manifested by high myocardial T2 relaxation times that normalized after clinical improvement in disease activity. These findings suggest that T2 relaxation values are a sensitive indicator of myocardial disease in patients with SLE and that myocardial T2 relaxation abnormality frequently occur in patients with active SLE, even in the absence of myocardial involvement by clinical criteria.

Poly(vinyl alcohol) cryogel phantoms for use in ultrasound and MR imaging

Poly(vinyl alcohol) cryogel, PVA-C, is presented as a tissue-mimicking material, suitable for application in magnetic resonance (MR) imaging and ultrasound imaging. A 10% by weight poly(vinyl alcohol) in water solution was used to form PVA-C, which is solidified through a freeze–thaw process. The number of freeze–thaw cycles affects the properties of the material. The ultrasound and MR imaging characteristics were investigated using cylindrical samples of PVA-C. The speed of sound was found to range from 1520 to 1540 m s−1, and the attenuation coefficients were in the range of 0.075–0.28 dB (cm MHz)−1. T1 and T2 relaxation values were found to be 718–1034 ms and 108–175 ms, respectively. We also present applications of this material in an anthropomorphic brain phantom, a multi-volume stenosed vessel phantom and breast biopsy phantoms. Some suggestions are made for how best to handle this material in the phantom design and development process.

Ressonância magnética dos hemangiomas hepáticos: avaliação das características morfológicas e quantitativas

OBJETIVO: Estudar as características morfológicas e quantitativas dos hemangiomas hepáticos na ressonância magnética. MATERIAL E MÉTODOS: Foram estudados, prospectivamente, 57 hemangiomas hepáticos presentes em 27 pacientes, com ressonância magnética de alto campo (1,5 T) utilizando seqüência spin-eco, imagens ponderadas em T1 e T2, com tempos de eco de até 160 ms. Foram avaliadas as características morfológicas dos hemangiomas, classificando-os em típicos ou atípicos. Também foram avaliadas características quantitativas das lesões (relação intensidade de sinal lesão/fígado, valores de tempo de relaxação T2 e índice simplificado T2) e feitas comparações entre tais características nos hemangiomas morfologicamente típicos e atípicos, e naqueles com dimensões &lt;FONT FACE=Symbol&gt;£&lt;/FONT&gt; 2,0 cm e &gt; 2,0 cm. RESULTADOS: Do total de hemangiomas estudados, 78,9% apresentaram características morfológicas típicas. Não houve diferença significante entre as características quantitativas de hemangiomas morfologicamente típicos e atípicos. Hemangiomas com dimensões &lt;FONT FACE=Symbol&gt;£&lt;/FONT&gt; 2,0 cm e &gt; 2,0 cm apresentaram comportamento semelhante em relação ao tempo de relaxação T2 e ao índice simplificado T2. Valores da relação intensidade de sinal lesão/fígado apresentaram diferenças significantes entre esses dois grupos. Os valores do tempo de relaxação T2, do índice simplificado T2 e da relação intensidade de sinal lesão/fígado caracterizaram corretamente 96,5%, 93% e 89,5% de todos os hemangiomas, respectivamente. CONCLUSÃO: A avaliação quantitativa dos hemangiomas hepáticos nas imagens por ressonância magnética é um método simples e, conjuntamente com a análise morfológica, propicia maior confiança para o diagnóstico.

Magnetic resonance imaging predicts neuropathology from soman-mediated seizures in the rodent.

Intoxication by the organophosphate compound soman causes prolonged seizures that lead to neuropathology in the brain. This MRI-based study describes the temporal and spatial evolution of brain pathology that follows soman-induced convulsions. We observed significant decreases in apparent diffusion coefficients (ADC; 23% below control) of the hippocampus and thalamus by 12 h after soman treatment. The ADC then returned to near normal values in all regions at 24 h but declined again during the next 7 days. These data suggest that the initial cellular degradation may be resolved but is ultimately followed by regional cellular remodeling. T2 relaxation values declined significantly at 12 h (37% decrease) returning to near normal values by 24 h. These data lend detail to the model suggesting that injured tissues experience an edematous influx that is resolved by 24 h. The imaging data was fully supported by histopathological comparisons where moderate cell loss and swelling within the hippocampus and piriform cortex was observed. This is the first report providing excellenttemporal and spatial resolution of emerging soman-mediated, seizure-induced neuropathology using MRI with histological correlation.

Cartilage swelling and loss in a spontaneous model of osteoarthritis visualized by magnetic resonance imaging

The objective of this study was to investigate whether the rate of change in cartilage pathology could be effectively monitored by magnetic resonance imaging (MRI) as part of a longitudinal investigation of an osteoarthritis model in vivo, and to define the minimum requirements necessary to establish disease progression. Magnetic resonance images of the knee of eight male Dunkin-Hartley guinea-pigs were obtained at 8, 12, 18, 24, 30, 36 and 52 weeks of age using a two-dimension spin-echo sequence with a TR of 1500 ms and TE of 40 ms. The total thickness of the femoral and tibial cartilage was measured from those images. Over the same time course, sets of spin-spin relaxation-weighted images were acquired from two additional animals of the same age, from which the T2 relaxation times of water in the articular cartilage were estimated and compared with those of muscle and adipose tissue within the same joint. The cartilage thickness of all the animals increased during the first 6 months, then either stayed thicker (4/8) or became progressively thinner (4/8). Up to 18 weeks of age, the cartilage T2 value was between 23-24 ms but became elevated by 30 weeks and the mean value was more than 40 ms at the end of the study, T2 values for the muscle and adipose tissue remained within the range 30-33 ms, or 47 ms, respectively. We concluded that in this model, cartilage thickness measurements from an magnetic resonance image would not provide a reliable marker to stage osteoarthritis progression partly because the cartilage was so thin in a joint of this size, but also because the changes with time were not linear but biphasic. However, quantitation of the T2 relaxation values may provide a more predictable indicator of cartilage pathology for longitudinal studies because the changes were monotonic and independent of cartilage thickness.

Echoplanar MR imaging for characterization of adrenal masses in patients with malignant neoplasms: preliminary evaluation of calculated T2 relaxation values.

We undertook this study to assess the utility of echoplanar MR imaging for distinguishing benign from malignant adrenal masses in patients with known malignant neoplasms. Thirty consecutive patients with 31 adrenal masses and a known malignant neoplasm underwent breath-hold echoplanar MR imaging with a repetition time of 6000 msec and four echo times (40, 80, 120, 160 msec) on a 1.5-T unit before biopsy. Subsequently, 10 masses were shown to be malignant at histologic examination, 12 masses were benign at histologic examination, and nine were thought to be benign because they had not changed in size at follow-up imaging. Mean lesion size was 2.4 +/- 2.1 cm. T2 calculations using regions of interest in the liver and adrenal mass were performed in each patient. The mean calculated T2 value of benign adrenal masses was 70.3 msec (SD, 11.6 msec) versus 104.6 msec (SD, 35.2 msec) for malignant adrenal masses (p = .013). Using a cutoff T2 value of 84 msec, 19 (90%) of 21 benign masses and nine (90%) of 10 malignant masses were correctly classified. The mean adrenal/liver T2 ratio was 1.4 (SD, 0.25) for benign lesions, and 2.1 (SD, 0.78) for malignant lesions (p = .017). Using a cutoff ratio of 1.60, 19 (90%) of 21 benign lesions and eight (80%) of 10 malignant lesions would have been correctly classified. This preliminary work suggests that obtaining T2 calculations from echoplanar MR images of adrenal masses is a useful technique for distinguishing benign from malignant adrenal masses in patients at risk for adrenal metastasis.

Interferon treatment of neuroendocrine tumour xenografts as monitored by MRI.

The neuroendocrine-differentiated colonic carcinoma cell line (LCC-18) was transplanted to 29 nude mice (Balb/c). The purpose of the present study was to establish an animal model that would allow monitoring with magnetic resonance imaging (MRI) of changes induced by interferon (IFN) therapy and to evaluate whether the therapeutic response, as expressed by changes in MR signal characteristics and tumour proliferation activity, could be modulated by different IFN dosages. IFN did not seem to have any obvious antiproliferative effect on the LCC-18 tumour cell line transplanted to nude mice and no convincing treatment-related changes in rho values or T1 and T2 relaxation values were observed. The animal model was probably unsuitable for demonstration of IFN effects.

Uterine cervical punch biopsy specimens can be analyzed by 1h mrs

Biopsy specimens of the uterine cervix, including colposcopically directed punch biopsy specimens of females with atypical Papanicolaou smear tests, are suitable for analysis by magnetic resonance (MR) spectroscopy. A narrow lined lipid MR spectrum, characteristic of malignant tissue, is obtained from a 6-mm3 biopsy specimen of histologically confirmed squamous carcinoma of the cervix. In contrast, specimens containing inflammatory cells generate a broad component only centered at 1.3 ppm with a T2 relaxation value of less than 350 ms. Most biopsy specimens which contain dysplastic cells or evidence of human papilloma virus (HPV) infection have a discernible lipid spectrum similar to that of the malignant tissue specimen. Long T2 relaxation values found in malignant tissue specimens at 1.3 and 1.2 ppm are observed in some but not all of the biopsies which show evidence of HPV infection. The suitability of small tissue samples, such as punch biopsy specimens, for study by MR illustrates the sensitivity of this technique and its potential as an aid to histopathological discrimination between the various precursor states of cervical cancer.

MRI of the Paranasal Sinuses and Nasal Cavity

In the evaluation of soft tissue masses of the paranasal sinuses and nasal cavity, MR has excelled, not only in sensitivity, but in specificity. Without question, MR has improved the diagnostic accuracy for distinguishing neoplasms from inflammatory diseases. This improved discrimination is primarily due to the combination of the superior soft tissue contrast of MRI and the widely disparate T2-relaxation values between the neoplasms and inflammatory processes indigenous to this anatomic area. MR's expanding role as the primary imaging modality for clinical problems in the sinonasal region will accompany the decrease in exam time and increase in spatial resolution. In the past few years there has been a rapid expansion in MRI's utility for a variety of clinical situations in the sinonasal region. This trend should accelerate, especially with the decrease in exam time and increase in spatial resolution that will accompany other expeditious technologic advancements.

Bone marrow imaging: magnetic resonance studies related to age and sex.

Measurements of T1 and T2 relaxation values and spin density of the lumbar vertebral bone marrow were performed in 212 patients, and the results were correlated with the patients' age and sex. T1 and T2 relaxation times for bone marrow in the lumbar vertebral bodies showed a progressive decrease with age for both sexes (except for the T2 relaxation values in female patients). The replacement of hematopoietic marrow by fatty marrow could explain the decrease in T1 and T2. The T1 and T2 values were in the same range for the first two age groups (age 1-10 years and age 21-40 years) and became slightly greater for the older female patients (age 51 years and older) than for the older males. This could be due to the loss of bone and mineral content, which is more rapid and significant for women. These normal T1 and T2 values may provide a baseline for future evaluation of diseases involving the lumbar spine.

NMR imaging and spectroscopy of experimental brain edema.

A canine model of experimental brain edema utilizing the classic cold lesion technique was used to identify the optimal nuclear magnetic resonance (NMR) spin-echo imaging parameters needed to detect cerebral edema with maximum sensitivity. Each animal was studied with four separate spin-echo sequences, utilizing pulse intervals ranging from 0.5 to 2.0 seconds. The echo delays following each pulse interval were 28 and 56 msec. Cerebral edema was best identified with the longest pulse interval (2.0 seconds), and the second echo delay (56 msec). T1 and T2 relaxation values were obtained from in vitro spectroscopy. The relaxation times were prolonged in the edematous white matter; however, absolute T1 and T2 values proved of little use in comparing different animals.

Multiple NMR T2 relaxation values in human liver tissue.

Twenty-one human hepatic liver biopsy samples were evaluated by nuclear magnetic resonance spectroscopy. This spectroscopy was performed by obtaining multiple and not single T2 values (T2-long and T2-short). Neoplastic tissue had greater T2-long and T2-short values than diffuse liver disease. The T2-short correlated, r = 0.947 (p less than 0.01), with the percentage of cancer cellularity within the tissue specimens. There was no correlation between the multiple T2 values and the degree of fibrosis and inflammation. Minimal correlation was noted between the T2-long and percentage of fat within the diffuse disease (cirrhotic) specimens, r = 0.636 (p less than 0.05). The possible reasons for the above findings are discussed.