In vivo proton (H1) magnetic resonance spectroscopy for cervical carcinoma

Magnetic Resonance Spectroscopy for Cervical Cancer: Review and Potential Prognostic Applications

This review article investigates the utilization of MRS in the setting of cervical cancer. A variety of different techniques have been used in this space including single-voxel techniques such as point-resolved spectroscopy (PRESS) and stimulated echo acquisition mode spectroscopy (STEAM). Furthermore, the experimental parameters for these acquisitions including field strength, repetition times (TR), and echo times (TE) vary greatly. This study critically examines eleven MRS studies that focus on cervical cancer. Out of the eleven studies, ten studies utilized PRESS acquisition, while the remaining study used STEAM acquisition. These studies generally showed that the choline signal is altered in cervical cancer (4/11 studies), the lipid signal is generally increased in cervical cancer or the lipid distribution is changed (5/11 studies), and that diffusion-weighted imaging (DWI) can quantitatively detect lower apparent diffusion coefficient (ADC) values in cervical cancer (2/11 studies). Two studies also investigated the role of MRS for monitoring treatment response and demonstrated mixed results regarding choline signal, and one of these studies showed increased lipid signal for non-responders. There are several new MRS technologies that have yet to be implemented for cervical cancer including advanced spectroscopic imaging and artificial intelligence, and those technologies are also discussed in the article.

Utilization of functional MRI in the diagnosis and management of cervical cancer

INTRODUCTION

Imaging is integral part of cervical cancer management. Currently, MRI is used for staging, follow up and image guided adaptive brachytherapy. The ongoing IQ-EMBRACE sub-study is evaluating the use of MRI for functional imaging to aid in the assessment of hypoxia, metabolism, hemodynamics and tissue structure. This study reviews the current and potential future utilization of functional MRI imaging in diagnosis and management of cervical cancer.

METHODS

We searched PubMed for articles characterizing the uses of functional MRI (fMRI) for cervical cancer. The current literature regarding these techniques in diagnosis and outcomes for cervical cancer were then reviewed.

RESULTS

The most used fMRI techniques identified for use in cervical cancer include diffusion weighted imaging (DWI) and dynamic contrast enhancement (DCE). DCE-MRI indirectly reflects tumor perfusion and hypoxia. This has been utilized to either characterize a functional risk volume of tumor with low perfusion or to characterize at-risk tumor voxels by analyzing signal intensity both pre-treatment and during treatment. DCE imaging in these situations has been associated with local control and disease-free survival and may have predictive/prognostic significance, however this has not yet been clinically validated. DWI allows for creation of ADC maps, that assists with diagnosis of local malignancy or nodal disease with high sensitivity and specificity. DWI findings have also been correlated with local control and overall survival in patients with an incomplete response after definitive chemoradiotherapy and thus may assist with post-treatment follow up. Other imaging techniques used in some instances are MR-spectroscopy and perfusion weighted imaging. T2-weighted imaging remains the standard technique used for diagnosis and radiation treatment planning. In many instances, it is unclear what additional information functional-MRI techniques provide compared to standard MRI imaging.

CONCLUSIONS

Functional MRI provides potential for improved diagnosis, prediction of treatment response and prognostication in cervical cancer. Specific sequences such as DCE, DWI and ADC need to be validated in a large prospective setting prior to widespread use. The ongoing IQ-EMBRACE study will provide important clinical information regarding these imaging modalities.

The contribution of the 1H-MRS lipid signal to cervical cancer prognosis: a preliminary study

Background

The aim of this study was to investigate the role of the lipid peak derived from ¹H magnetic resonance (MR) spectroscopy in assessing cervical cancer prognosis, particularly in assessing response to neoadjuvant chemotherapy (NACT) of locally advanced cervical cancer (LACC).

Methods

We enrolled 17 patients with histologically proven cervical cancer who underwent 3-T MR imaging at baseline. In addition to conventional imaging sequences for pelvic assessment, the protocol included a single-voxel point-resolved spectroscopy (PRESS) sequence, with repetition time of 1,500 ms and echo times of 28 and 144 ms. Spectra were analysed using the LCModel fitting routine, thus extracting multiple metabolites, including lipids (Lip) and total choline (tCho). Patients with LACC were treated with NACT and reassessed by MRI at term. Based on tumour volume reduction, patients were classified as good responder (GR; tumour volume reduction > 50%) and poor responder or nonresponder (PR-or-NR; tumour volume reduction ≤ 50%).

Results

Of 17 patients, 11 were LACC. Of these 11, only 6 had both completed NACT and had good-quality ¹H-MR spectra; 3 GR and 3 PR-or-NR. A significant difference in lipid values was observed in the two groups of patients, particularly with higher Lip values and higher Lip/tCho ratio in PR-NR patients (p =0.040). A significant difference was also observed in choline distribution (tCho), with higher values in GR patients (p = 0.040).

Conclusions

Assessment of lipid peak at ¹H-MR spectroscopy could be an additional quantitative parameter in predicting the response to NACT in patients with LACC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41747-022-00300-1.

Proton MRS of cervical cancer at 7 T

The differentiation grade of cervical cancer is histologically assessed by examining biopsies or surgical specimens. MRS is a highly sensitive technique that images tissue metabolism and can be used to increase the specificity of tissue characterization in a non-invasive manner. We aim to explore the feasibility of using in vivo ¹ H-MRS at 7 T in women with cervical cancer to study tissue fatty acid composition. 10 women with histologically proven Stage IB1-IIB cervical cancer were scanned with a whole-body 7 T MR system with a multi-transmit system and an internal receive only monopole antenna. A STEAM sequence was used to obtain ¹ H-MRS data. Fatty acid resonances were fitted with Lorentzian curves and the 2.1 ppm/1.3 ppm ratios were calculated. ¹ H-MRS data showed fatty acid signals resonating at 2.1 ppm, 1.9 ppm, 1.5 ppm, 1.3 ppm and 0.9 ppm. Mean 2.1/1.3 ppm ratios were 0.019 ± 0.01, 0.021 ± 0.006, 0.12 ± 0.089 and 0.39 ± 0.27 for normal, Grade I, Grade II and Grade III groups respectively. Poorly differentiated tumor tissue (Grade III) showed elevated fatty acid ratios when compared with the well differentiated tumor (Grade I) or normal tissue. ¹ H-MRS in cervical cancer at 7 T is feasible and individual fatty acid signals were detected. In addition, poorly differentiated tumors show more fatty acid unsaturation. The 2.1 ppm/1.3 ppm ratio has potential for tumor characterization in a non-invasive manner for uterine cervical cancer.

Proton NMR characterization of intact primary and metastatic melanoma cells in 2D & 3D cultures

Objective

To characterize the differences between the primary and metastatic melanoma cell lines grown in 2D cultures and 3D cultures.

Methods

Primary melanoma cells (WM115) and metastatic melanoma cells (WM266) extracted from a single donor was cultured in 2D as well as 3D cultures. These cells were characterized using proton NMR spectrometry, and the qualitative chemical shifts markers were identified and discussed.

Results

In monolayer culture (2D), we observed one qualitative chemical shift marker for primary melanoma cells. In spheroid cultures (3D), we observed nine significant chemical shifts, of which eight markers were specific for primary melanoma spheroids, whereas the other one marker was specific to metastatic melanoma spheroids. This study suggests that the glucose accumulation and phospholipid composition vary significantly between the primary and metastatic cells lines that are obtained from a single donor and also with the cell culturing methods. 14 qualitative chemical shift markers were obtained in the comparison between monolayer culture and spheroids cultures irrespective of the differences in the cell lines. Among which 4 were unique to monolayer cultures whereas 10 chemical shifts were unique to the spheroid cultures. This study also shows that the method of cell culture would drastically affect the phospholipid composition of the cells and also depicts that the cells in spheroid culture closely resembles the cells in vivo.

Conclusion

This study shows the high specificity of proton NMR spectrometry in characterizing cancer cell lines and also shows the variations in the glucose accumulation and phospholipid composition between the primary and metastatic melanoma cell lines from the same donor. Differences in the cell culture method does plays an important role in phospholipid composition of the cells.

Electronic supplementary material

The online version of this article (doi:10.1186/s40659-017-0117-8) contains supplementary material, which is available to authorized users.

Proton magnetic resonance spectroscopy in oncology: the fingerprints of cancer?

Abnormal metabolism is a key tumor hallmark. Proton magnetic resonance spectroscopy (1H-MRS) allows measurement of metabolite concentration that can be utilized to characterize tumor metabolic changes. 1H-MRS measurements of specific metabolites have been implemented in the clinic. This article performs a systematic review of image acquisition and interpretation of 1H-MRS for cancer evaluation, evaluates its strengths and limitations, and correlates metabolite peaks at 1H-MRS with diagnostic and prognostic parameters of cancer in different tumor types.

Role of 3T multiparametric-MRI with BOLD hypoxia imaging for diagnosis and post therapy response evaluation of postoperative recurrent cervical cancers

•

In operated cervix cancer, the accuracy of diagnosing vaginal vault/local recurrent lesions was higher at combined multiparametric MR imaging and conventional MR imaging (100%) than at conventional MR imaging (70%) or multiparametric MR imaging (96.7%) alone.

•

We found a significant correlation between percentage tumor regression and pre-treatment parameters: NEI (p = 0.02), the maximum slope (p = 0.04), mADC value (p = 0.001) and amount of hypoxic fraction present in the pretherapy MRI (p = 0.01).

•

Multiparametric and BOLD hypoxia MR Imaging are feasible and reliable in diagnosing post-operative recurrence in cervical cancer and should be applied when there is clinical suspicion of post-operative recurrence.

•

Quantitative image features obtained at multiparametric-MRI with BOLD hypoxia imaging has potential to be an appropriate and reliable biologic target for radiation dose painting to optimize therapy in future.

Objectives

To assess the diagnostic value of multiparametric-MRI (MPMRI) with hypoxia imaging as a functional marker for characterizing and detecting vaginal vault/local recurrence following primary surgery for cervical cancer.

Methods

With institutional review board approval and written informed consent 30 women (median age: 45 years) from October 2009 to March 2010 with previous operated carcinoma cervix and suspected clinical vaginal vault/local recurrence were examined with 3.0T-MRI. MRI imaging included conventional and MPMRI sequences [dynamic contrast enhanced (DCE), diffusion weighted (DW), 1H-MR spectroscopy (1HMRS), blood oxygen level dependent hypoxia imaging (BOLD)]. Two radiologists, blinded to pathologic findings, independently assessed the pretherapy MRI findings and then correlated it with histopathology findings. Sensitivity, specificity, positive predictive value, negative predictive value and their confidence intervals were calculated. The pre and post therapy conventional and MPMRI parameters were analyzed and correlated with response to therapy.

Results

Of the 30 patients, there were 24 recurrent tumors and 6 benign lesions. The accuracy of diagnosing recurrent vault lesions was highest at combined MPMRI and conventional MRI (100%) than at conventional-MRI (70%) or MPMRI (96.7%) alone. Significant correlation was seen between percentage tumor regression and pre-treatment parameters such as negative enhancement integral (NEI) (p = 0.02), the maximum slope (p = 0.04), mADC value (p = 0.001) and amount of hypoxic fraction on the pretherapy MRI (p = 0.01).

Conclusion

Conventional-MR with MPMRI significantly increases the diagnostic accuracy for suspected vaginal vault/local recurrence. Post therapy serial MPMRI with hypoxia imaging follow-up objectively documents the response. MPMRI and BOLD hypoxia imaging provide information regarding tumor biology at the molecular, subcellular, cellular and tissue levels and this information may be used as an appropriate and reliable biologic target for radiation dose painting to optimize therapy in future.

Novel functional magnetic resonance imaging biomarkers for assessing response to therapy in hepatocellular carcinoma

The established and adapted image biomarkers based on size for tumor burden measurement continue to be applied to hepatocellular carcinoma (HCC) as size measurement can easily be used in clinical practice. However, in the setting of novel targeted therapies and liver directed treatments, simple tumor anatomical changes can be less informative and usually appear later than biological changes. Functional magnetic resonance imaging (MRI) has a potential to be a promising technique for assessment of HCC response to therapy. In this review, we discuss various functional MRI biomarkers that play an increasingly important role in evaluation of HCC response after treatment.

Plasma-free amino acid profiling of cervical cancer and cervical intraepithelial neoplasia patients and its application for early detection

In this study, plasma-free amino acid profiles were used to investigate pre-cancerous cervical intraepithelial neoplasia (CIN) and cervical squamous cell carcinoma (CSCC) metabolic signatures in plasma. Additionally, the diagnostic potential of these profiles was assessed, as well as their ability to provide novel insight into CSCC metabolism and systemic effects. Plasma samples from CIN patients (n = 26), CSCC patients (n = 22), and a control healthy group (n = 35) were analyzed by high-performance liquid chromatography, and their spectral profiles were subjected to the t test for statistical significance. Potential metabolic biomarkers were identified using database comparisons that examine the significance of metabolites. Compared with healthy controls, patients with CIN and CSCC demonstrated lower levels of plasma amino acids; plasma levels of arginine and threonine were increased in CIN patients but were decreased in cervical cancer patients. Additionally, the levels of a larger group of amino acids (aspartate, glutamate, asparagine, serine, glycine, histidine, taurine, tyrosine, valine, methionine, lysine, isoleucine, leucine, and phenylalanine) were gradually reduced from CIN to invasive cancer. These findings suggest that plasma-free amino acid profiling has great potential for improving cancer screening and diagnosis and for understanding disease pathogenesis. Plasma-free amino acid profiles may have the potential be used to determine cancer diagnoses in the early stage from a single blood sample and may enhance our understanding of its mechanisms.

Adrenal masses: characterization with in vivo proton MR spectroscopy--initial experience

PURPOSE

To prospectively determine the accuracy of in vivo proton ((1)H) magnetic resonance (MR) spectroscopy in distinguishing adrenal adenomas, pheochromocytomas, adrenocortical carcinomas, and metastases, with histologic or computed tomographic findings and follow-up data as the reference standards.

MATERIALS AND METHODS

This study was approved by the institutional ethics committee, and informed consent was obtained. Sixty consecutive patients (24 male and 36 female patients; mean age, 53 years) harboring adrenal tumors larger than 2 cm in diameter (mean diameter, 4.6 cm +/- 3.4 [standard deviation]) entered the study and were examined with a 1.5-T MR imaging system and point-resolved multivoxel (1)H MR spectroscopy. Thirty-eight patients had adenomas; 10, pheochromocytomas; five, carcinomas; and seven, metastases. Amplitude values for choline, creatine, lipid, and a metabolite peak at precession frequency of 4.0-4.3 ppm were measured. Metabolite ratios (choline-creatine, choline-lipid, lipid-creatine, and 4.0-4.3 ppm/creatine) and cutoff values (obtained by using receiver operating characteristic analyses) were obtained and compared for each type of adrenal mass, which was identified previously on the basis of clinical, hormonal, and pathologic evidence. Results were evaluated with chi(2) and Student t tests. Significance was inferred at P < .05.

RESULTS

Cutoff values of 1.20 for the choline-creatine ratio (92% sensitivity, 96% specificity; P < .01), 0.38 for the choline-lipid ratio (92% sensitivity, 90% specificity; P < .01), and 2.10 for the lipid-creatine ratio (45% sensitivity, 100% specificity) enabled adenomas and pheochromocytomas to be distinguished from carcinomas and metastases. A 4.0-4.3 ppm/creatine ratio greater than 1.50 enabled distinction of pheochromocytomas and carcinomas from adenomas and metastases (87% sensitivity, 98% specificity; P < .01). The best distinction was obtained by comparing choline-creatine and 4.0-4.3 ppm/creatine ratios.

CONCLUSION

(1)H MR spectroscopy can be used to characterize adrenal masses on the basis of spectral findings for benign adenomas, carcinomas, pheochromocytomas, and metastases.

Ressonância magnética no estadiamento dos tumores de colo uterino

O câncer de colo uterino é a maior causa de morte entre mulheres em todo o mundo, notadamente nos países em desenvolvimento. A Federação Internacional de Ginecologia e Obstetrícia preconiza o estadiamento durante o ato operatório, porém nos casos mais avançados a abordagem terapêutica não é cirúrgica. Nestes casos, o estadiamento, em geral, é feito com o exame clínico ginecológico e exames básicos de imagem. Entretanto, essa forma de abordagem não expressa a real extensão da doença e não inclui importantes fatores prognósticos como volume tumoral, invasão estromal e acometimento linfonodal. A ressonância magnética está sendo cada vez mais utilizada para este fim, pois nos estádios iniciais seu desempenho pode ser comparado aos achados intra-operatórios e nos estádios avançados se mostra superior em relação à avaliação clínica. A ressonância magnética apresenta excelente resolução para diversas densidades das estruturas pélvicas, não utiliza radiação ionizante, é confortável, melhora o estadiamento, permite a detecção precoce de recidiva e a identificação de fatores prognósticos fidedignos que contribuem na decisão e predição dos resultados terapêuticos, com excelente custo-efetividade. Este artigo tem como objetivo revisar os aspectos da ressonância magnética mais importantes no estadiamento desta doença.

Image-based brachytherapy: a forum for collaboration between radiation oncologists and diagnostic radiologists

There has been increased interest in implementing image-guided brachytherapy to better define the structures of interest and assess the radiation dose distribution in tumors and surrounding normal tissues. This is particularly helpful in the treatment of pelvic malignancies such as cervix cancer and prostate cancer, in which the tumor lies in close relationship to the bladder and rectosigmoid. This provides a forum for the collaboration of diagnostic radiologists and radiation oncologists.

Imaging the female pelvis at 3.0 T

Three-Tesla whole body imaging is rapidly becoming part of routine clinical practice. Although it is generally thought that pelvic imaging at 3.0 T will be beneficial because of increased signal to noise and greater spectral separation, adjustments in protocol and sequence parameters are necessary to optimize image quality. The question remains as to whether 3.0-T imaging will offer further benefits beyond 1.5 T in terms of lesion characterization and functional imaging. This article aims to address safety concerns and to illustrate the potential benefits and technical challenges of imaging the female pelvis at 3.0 T. Imaging protocols and sequence parameters for routine gynecologic indications are suggested, and potential clinical applications at 3.0 T are discussed such as magnetic resonance spectroscopy, perfusion, diffusion weighted imaging, and the use of alternate contrast agents.

Early response of hepatocellular carcinoma to transcatheter arterial chemoembolization: choline levels and MR diffusion constants--initial experience

PURPOSE

To prospectively investigate the apparent diffusion coefficient (ADC) and choline levels measured at hydrogen 1 ((1)H) magnetic resonance (MR) spectroscopy, to monitor therapeutic responses of hepatocellular carcinoma (HCC) to transcatheter arterial chemoembolization (TACE).

MATERIALS AND METHODS

Institutional review board approval was obtained, and all patients and control subjects provided informed consent. Histologically proved large HCCs (>3 cm in diameter) were evaluated in 20 patients (16 men and four women; mean age, 59 years; range, 34-80 years) before TACE and 2-3 days after TACE. A control group of eight adults (five men and three women; mean age, 43 years; range, 24-76 years) with normal livers was examined by using the same protocol. Hepatic choline levels were measured by means of an external phantom replacement method, quantifying the peak at 3.2 ppm at (1)H MR spectroscopy. ADCs were measured for all lesions. A Wilcoxon rank sum test was used to compare absolute choline concentrations and ADCs at baseline between HCCs and normal liver parenchyma. Changes in choline levels and ADCs in the tumors before and after TACE were analyzed by using the Wilcoxon signed rank test.

RESULTS

The median preoperative choline level in patients with HCC (measured in 18 of the 20 patients) was 4.0 mmol/L (range, 0.0-17.2 mmol/L), which was significantly higher than that in patients with normal livers (n = 8) (median, 1.6 mmol/L; range, 0.0-2.1 mmol/L; P < .01). Among 18 patients with HCC, choline levels decreased significantly from before TACE to after TACE (P < .01). A significant increase in ADC from before TACE to after TACE in the 20 patients with HCC was also found (P < .01).

CONCLUSION

Hepatic choline levels and ADCs may allow monitoring of therapeutic responses of HCC to TACE although larger, more definitive and quantitative studies with clinical end points are needed.

In vivo detection of metabolic changes by 1H-MRS in the DEN-induced hepatocellular carcinoma in Wistar rat

PURPOSE

To investigate the serial changes of the hepatic metabolites in a chemical-induced rat model of hepatocellular carcinoma (HCC) in vivo by a clinical 1.5 T MR scanner.

METHODS

Diethyl nitrosamine (DEN) induced HCC model rats (n=60) and control rats (n=20) were included. From week 7 to week 20 after DEN administration, every other week 10-12 animals (8-9 treated and 2-3 controls) were randomly scanned before being sacrificed. According to the pathologic changes, the whole process of tumorigenesis was divided into early and late periods (week 7-13 and week 14-20, respectively). The serial hepatic changes were tested by both routine MRI and single voxel 1H-MRS and compared with pathological results. Point resolved spectroscopy sequence (PRESS) was used for the location in MRS. The integrations of lipid- and choline-containing metabolites were calculated and analyzed.

RESULTS

All of the listed tests were fully finished in 66 rats (48 treated and 18 controls). Of the MRS curves, 65.2% (43/66) could be analyzed (mainly with resistant baseline with peaks appearing at right positions). From those qualified MRS curves, there were up to seven peaks which could be identified. The peaks of methylene lipids and methyl lipids were combined together in most cases and became the most notable component. The relative integrals of the combined lipid peak and that of the choline-containing compounds in different groups and stages were measured. Comparing with that of the controls of the same stage, the lipid of treated rats decreased in the late stage, and the choline-containing compounds increased in the same stage. Statistically significant differences were found (P<0.05) for the integrals of the lipid and the choline-containing metabolites between treated and controls in the late stage.

CONCLUSIONS

Our initial studies for the integrals of the lipid compounds and the choline-containing metabolites might be useful for a better understanding of the metabolic activity of this DEN-induced rat HCC model.

Metabolic Changes in Pelvic Lesions: Findings at Proton MR Spectroscopic Imaging

OBJECTIVE

The purpose of this study is to investigate the in vivo magnetic resonance spectroscopic (MRS) features of pelvic lesions using long echo time and to characterize the spectral patterns of various pathological entities.

MATERIALS AND METHODS

17 patients with surgically and histopathologically confirmed pelvic lesions underwent long echo-time MRS, and the results obtained were analyzed. Before laparotomy, choline (Cho), lactate, lipid and creatine (Cr) levels of all lesions were measured by single voxel MRS (point-resolved spectroscopy technique, TE 136 ms). Voxels were placed in the center of the lesions. The MRS results of lesions were compared with the final histopathological diagnoses.

RESULTS

Spectroscopy analysis of serous, mucinous and undifferentiated carcinoma of the ovary revealed Cho, lactate and lipid signals, but granulosa-theca cell tumor showed only a lipid signal. The Cho signal was obtained from only 3 patients with mature cystic teratoma but none of the other benign ovarian tumors and pelvic abscesses. A lipid signal was detected in 3 patients diagnosed with pelvic abscess and all benign ovarian tumors. In addition to the lipid signal, a lactate signal was detected in the spectra of two pelvic abscesses. One case of endometrioma and 1 case of teratoma did not show any signal.

CONCLUSION

MRS demonstrates significant differences in metabolite concentration between benign and malignant ovarian tumors and pelvic abscesses. MRS may therefore be helpful in the differential diagnosis of adnexal lesions.

Proton magnetic resonance spectroscopy in neuroblastoma: Current status, prospects and limitations

Non-invasive biological information about residual neuroblastoma tumour tissue could allow treatment monitoring without the need for repeated biopsies. Magnetic resonance spectroscopy (MRS) can be performed with standard MR-scanners, providing specific biochemical information from selected tumour regions. By proton 1H-MRS, lipids, certain amino acids and lactate can be detected and their relative concentrations estimated in vivo. Using experimental models of neuroblastoma, we have described the potential of 1H-MRS for the prediction of tumour tissue viability and treatment response. Whereas viable neuroblastoma tissue is dominated by the choline 1H-MRS resonance, cell death as a consequence of spontaneous necrosis or successful treatment with chemotherapy, angiogenesis inhibitors, or NSAIDs is associated with decreased choline content. Therapy-induced neuroblastoma cell death is also associated with enhanced 1H-MRS resonances from mobile lipids and polyunsaturated fatty acids. The mobile lipid/choline ratio correlates significantly with cell death and based on the dynamics of this ratio tumour regression or continued growth (drug resistance) after chemotherapy can be predicted in vivo. The implications of these findings are discussed with focus on the potentials and limitations of introducing 1H-MRS for clinical assessment of treatment response in children with neuroblastoma. Biochemical monitoring of neuroblastoma with 1H-MRS could enable tailoring of individual therapy as well as provide early pharmacodynamic evaluation of novel therapeutic modalities.

In vivo magnetic resonance spectroscopy in cancer

Magnetic resonance spectroscopy (MRS) has been used for more than two decades to interrogate metabolite distributions in living cells and tissues. Techniques have been developed that allow multiple spectra to be obtained simultaneously with individual volume elements as small as 1 uL of tissue (i.e., 1 x 1 x 1 mm(3)). The most common modern applications of in vivo MRS use endogenous signals from (1)H, (31)P, or (23)Na. Important contributions have also been made using exogenous compounds containing (19)F, (13)C, or (17)O. MRS has been used to investigate cardiac and skeletal muscle energetics, neurobiology, and cancer. This review focuses on the latter applications, with specific reference to the measurement of tissue choline, which has proven to be a tumor biomarker that is significantly affected by anticancer therapies.

Detection and differentiation of lactate and lipids by single-voxel proton MR spectroscopy

The signals of lactate and lipids partially overlap in single-voxel proton MR spectroscopy (1HMRS), sometimes making them difficult to differentiate in clinical settings. Our aim in this study was to identify lactate and lipids by varying the echo time (TE). We expect that the accurate detection of lactate and lipids will have high diagnostic value in the diagnosis of brain tumors. Following our protocol, we obtained meaningful 1HMRS spectra from 213 patients, including 163 patients with brain tumors, between August 1999 and February 2004. 1HMRS was performed with a TE of 144 ms followed by a TE of 30 ms and/or a TE of 288 ms, if necessary. For the 213 patients, lactate level was "negative" in 47 patients, "positive" in 131 patients, and "strongly positive" in 35 patients. The lipid level was "negative" in 90 patients, "positive" in 56 patients, and "strongly positive" in 67 patients. Based on logistic discriminant analyses of neuro-epithelial tumor WHO grade and lactate and lipid levels, lactate and lipid levels were significant between WHO grades 2 and 3 (P=0.0239) and between grades 3 and 4 (P=0.0347). Lipids are a more significant factor for the discrimination between WHO grades 2 and 3 (P=0.0073) and between grades 3 and 4 (P=0.0048). With our method of varying the TE, it is possible accurately and efficiently to detect lactate and lipids in the brain. We found a significant correlation between lactate and lipid expression and WHO grade of neuro-epithelial tumors.

Synchronous endometrial and cervical tumors in a 26-year-old nullipara: diagnostic modalities updated

Proton magnetic resonance spectroscopy (MRS), performed on conventional magnetic resonance imaging (MRI) scanners, provides useful information at the biochemical level. MRS has been used to measure tissue concentrations of proton-containing compounds such as organic and amino acids, and sugars in living tissues. We have used MRS in a 26-year-old female with suspected cervical and endometrial carcinomas. With the use of the above mentioned technique, biochemical differences in the endometrium and the cervix tissues were detected. The presented case is the first virgin patient in the relevant literature in whom endometrial and cervical carcinoma was detected. Choline (Cho), creatine (Cr), N-acetylaspartate (NAA), lipid and lactate region of the MRS spectrum suggested that the technique could be used as an indicator of metabolic alterations in the cervical and endometrial tumor cells.

In vivo proton magnetic resonance spectroscopy of large focal hepatic lesions and metabolite change of hepatocellular carcinoma before and after transcatheter arterial chemoembolization using 3.0-T MR scanner

PURPOSE

To investigate the value of in vivo proton magnetic resonance spectroscopy (MRS) in the assessment of large focal hepatic lesions and to measure the metabolite change of hepatocellular carcinoma (HCC) after transcatheter arterial chemoembolization (TACE) using 3.0-T scanner.

MATERIALS AND METHODS

In this prospective study, 43 consecutive patients with large (not less than 3 cm in diameter) hepatic tumors and eight normal volunteer were included. MRS of the lesions in addition to uninvolved liver parenchyma was carried out using a whole-body 3.0-T scanner. Among the patients with proven HCC, eight lesions were evaluated before and two to five days after TACE. The choline-to-lipid (cho/lipid) ratio was measured by dividing the peak area of choline at 3.2 ppm by the peak area of lipid at 1.3 ppm. The sensitivity and specificity profiles of MRS in the diagnosis of malignant hepatic tumors were determined by plotting empirical receiver operating characteristic (ROC) curve. The mean cho/lipid ratios in different groups before and after TACE were also measured.

RESULTS

The technical success rate for MRS was 90% (53/59). The ROC curve showed proton MRS has moderate discriminating ability in diagnosing malignant hepatic tumors, although the sensitivity was less than 50% while 1-specificity was less than 20%. The area under the curve was 0.71 (P < 0.05). The mean +/- 1 standard error (SE) of cho/lipid ratios for uninvolved liver (N = 8), benign tumor (N = 8), and malignant tumor (N = 21; 19 HCC, one angiosarcoma, and one lymphoma) were 0.06 +/- 0.02, 0.02 +/- 0.02, and 0.17 +/- 0.05, respectively. A significantly statistical difference (ANOVA planned contrast test, P = 0.01 and Games-Howell procedure, P = 0.03) was achieved in the mean cho/lipid ratio between malignant and benign tumors. The mean cho/lipid ratios were significantly decreased from 0.23 +/- 0.11 before TACE to 0.01 +/- 0.00 after the treatment (t = 2.01, P < 0.05, one-tail paired t-test; z = -2.37, P < 0.05, Wilcoxon Signed Ranks Test).

CONCLUSION

In vivo proton MRS is technically feasible for the evaluation of focal hepatic lesions. The technique has potential in the detection of early metabolite change in malignant liver tumors after TACE but limitation still exists in clear differentiation between normal liver and benign and malignant tumor.

Characterization of Bone and Soft-Tissue Tumors with in Vivo1H MR Spectroscopy: Initial Results

PURPOSE

To determine if in vivo detection of choline by using hydrogen 1 (1H) magnetic resonance (MR) spectroscopy with dynamic contrast material-enhanced MR imaging can help differentiate between benign and malignant musculoskeletal tumors.

MATERIALS AND METHODS

MR imaging was performed in 36 consecutive patients with bone and soft-tissue tumors larger than 1.5 cm in diameter. Examinations were performed at 1.5 T with a surface coil appropriate for the location of the lesions. Single-voxel 1H MR spectroscopy was performed by using a point-resolved spectroscopic sequence with echo times of 40, 135, and 270 msec. The volume of interest within lesions was positioned on the areas of early enhancement (<8 seconds after arterial enhancement) according to the findings of dynamic contrast-enhanced MR imaging with subtraction. The criterion for determining whether choline was present in a lesion was a clearly identifiable peak at 3.2 ppm in at least two of the three spectra acquired at echo times. MR spectroscopic results and histopathologic findings were determined in blinded fashion and compared with kappa statistics. P <.001 was considered to indicate a significant difference.

RESULTS

Choline was detected in 18 of 19 patients with malignant tumors and in three of 17 patients with benign lesions. The three benign lesions included one perineurioma, one giant cell tumor, and one abscess. Choline was not detected in 14 patients with benign lesions nor in one patient with a densely ossifying low-grade parosteal osteosarcoma. In vivo 1H MR spectroscopy characterized bone and soft-tissue tumors, resulting in a sensitivity of 95%, specificity of 82%, and accuracy of 89% (P <.001).

CONCLUSION

Choline can be reliably detected in large malignant bone and soft-tissue tumors by using a multiecho point-resolved spectroscopic protocol. 1H MR spectroscopy can help differentiate malignant from benign musculoskeletal tumors by revealing the presence or absence of water-soluble choline metabolites.

Magnetic resonance spectroscopy features of uterine leiomyomas

OBJECTIVE

The purpose of this study is to investigate the in vivo magnetic resonance spectroscopy features of uterine leiomyomas using long echo time and to characterize the spectral patterns of these lesions.

METHODS

We calculated metabolites in 15 patients with uterine leiomyomas and myometrium of 20 healthy control subjects using single-voxel proton MR spectroscopy (point resolved spectroscopy technique, TE:136 ms). Voxels were placed at the center of the uterine leiomyomas. The peak areas of creatine, choline, lipid and lactate were determined. The MR spectroscopy results of uterine leiomyomas were compared with the spectroscopy results obtained from the myometrium of healthy control subjects.

RESULTS

The characteristically obtained signal was choline, which was detected not only in 14 of the 15 leiomyomas (93.3%) but also in 18 of the 20 myometrium of control subjects (90%). The lipid signals were determined in 9 of 15 patients with uterine leiomyomas (60%) and 8 of 20 control subjects (40%). The lactate signal was obtained from six of 15 patients with leiomyomas (40%) but only two of myometrium (10%). The creatine signal was obtained from 4 of 15 patients with leiomyomas (26.6%) and 5 of 20 myometrium (25%). Among the tested parameters only lactate peak was statistically significant (p < 0.05).

CONCLUSION

Proton MR spectroscopic imaging may be helpful for the investigation of the underlying pathophysiology of uterine leiomyomas. The presence of lactate and lipid signals in the spectrum may be a useful indicator of metabolic pathway of uterine leiomyomas.

In vivo proton magnetic resonance spectroscopy in the evaluation of the endometrium

BACKGROUND

The purposes of this study were to compare proton magnetic resonance (MR) spectroscopic evaluation of the endometrium with histology obtained by endometrial biopsy in women undergoing diagnostic curettage and to determine whether screening with MR spectroscopy (MRS) might be useful in the evaluation of the endometrium.

METHODS

Twenty-three consecutive women who were scheduled for endometrial biopsy were included in the study. The women were evaluated by MRS, performed immediately before the endometrial biopsy. The MRS results were compared with the histological findings obtained from the endometrial biopsy.

RESULTS

All of the cases were proven by pathological examination, and their diagnoses were secretory endometrium (11 cases), proliferative endometrium (seven cases) and disordered proliferative endometrium (five cases). The characteristically obtained signals of choline (Cho) and lipid were detected in all subjects in the secretory endometrium group. In the same group, eight patients showed lactate signals and six showed creatine (Cr) signals. In the disordered proliferative endometrium group, four patients showed lipid plus Cho signals. Two patients in the same group demonstrated both lactate and Cr signals. All patients in the proliferative endometrium group showed Cho signals, two patients demonstrated lactate plus Cho signals, and none of the patients in this group showed lipid and Cr signals.

CONCLUSION

Proton magnetic resonance spectra can register certain metabolic differences in human endometrium in its different stages.

1H magnetic resonance spectroscopy of invasive cervical cancer: an in vivo study with ex vivo corroboration

The objective of this study was to establish in vivo (1)H-magnetic resonance (MR) spectroscopic appearances of cervical cancer using an endovaginal receiver coil and corroborate findings with magic angle spinning (MAS) MR spectroscopy of tissue samples. Fifty-three women (14 controls and 39 with cervical cancer) underwent endovaginal coil MR imaging at 1.5 T with T(1)- and T(2)-weighted scans sagittal and transverse to the cervix. Localized (1)H MR spectra (PRESS technique, TR 1600 ms, TE 135 ms) were accumulated in all controls and 29 cancer patients whose tumour filled > 50% of a single 3.4 cm(3) voxel. Peaks from triglyceride-CH(2) and -CH(3) were defined as present and in-phase (with the choline resonance), present but out-of-phase, or not present. Peak areas of choline-containing compounds were standardized to the area of unsuppressed tissue water resonance. Comparisons in observed resonances between groups were made using Fisher's exact test (qualitative data) and a t-test (quantitative data). Biopsies from these women analysed using MAS-MR spectroscopy and normalized to the intensity of an external standard of silicone rubber were similarly compared. Adequate water suppression permitted spectral analysis in 11 controls and 27 cancer patients. In-phase triglyceride-CH(2) resonances (1.3 ppm) were observed in 74% of tumours but in no control women (p < 0.001). No differences were observed in the presence of a 2 ppm resonance, choline-containing compounds or creatine in cancer compared with control women. However, ex vivo analysis showed significant differences not only in -CH(2), but also in -CH(3), a 2 ppm resonance, choline-containing compounds and creatine between tissues from control women and cancer tissue (p < 0.001, = 0.001, = 0.036, < 0.001 and = 0.004 respectively). On in vivo (1)H-MR spectroscopy, the presence of positive triglyceride-CH(2) resonances can be used to detect and confirm the presence of cervical cancer. However, technical improvements are required before routine clinical use.

1H magnetic resonance spectroscopy of preinvasive and invasive cervical cancer: In vivo-ex vivo profiles and effect of tumor load

PURPOSE

To compare in vivo (1)H magnetic resonance (MR) spectra of preinvasive and invasive cervical lesions with ex vivo magic angle spinning (MAS) spectra of intact biopsies from the same subjects and to establish the effects of tumor load in the tissue sampled on the findings.

MATERIALS AND METHODS

A total of 51 subjects (nine with normal cervix, 10 with cervical intraepithelial neoplasia [CIN], and 32 with cervical cancer) underwent endovaginal MR at 1.5 T. Single-voxel (3.4 cm(3)) (1)H MR spectra were acquired and voxel tumor load was calculated (tumor volume within voxel as a percentage of voxel volume). Resonances from triglycerides -CH(2) and -CH(3) and choline-containing compounds (Cho) were correlated with voxel tumor load. Biopsies analyzed by (1)H MAS-MR spectroscopy (MRS) had metabolite levels correlated with tumor load in the sample at histology.

RESULTS

In vivo studies detected Cho in normal, CIN, and cancer patients with no significant differences in levels (P = 0.93); levels were independent of voxel tumor load. Triglyceride -CH(2) and -CH(3) signals in-phase with Cho were present in 77% and 29%, respectively, of cancer subjects (but not in normal women or those with CIN), but did not correlate with voxel tumor load. Ex vivo cancer biopsies showed levels of triglycerides -CH(2) and -CH(3) and of Cho that were significantly greater than in normal or CIN biopsies (P < 0.05); levels were independent of the tumor load in the sample. The presence of -CH(2) in vivo predicted the presence of cancer with a sensitivity and specificity of 77.4% and 93.8% respectively, positive (PPV) and negative (NPV) predictive values were 96% and 68.2%; for -CH(2) ex vivo, sensitivity was 100%; specificity, 69%; PPV, 82%; and NPV, 100%.

CONCLUSION

Elevated lipid levels are detected by MRS in vivo and ex vivo in cervical cancer and are independent of tumor load in the volume of tissue sampled.

Immunotherapy: new options in breast cancer treatment

Immunotherapy is a promising new approach in breast cancer treatment, complementing surgery, chemotherapy, radiation and antihormonal therapy. Primarily, two treatment options are available which are supported by a rapidly growing body of clinical evidence. These are active specific immunotherapy with Theratope and passive immunotherapy targeting the HER-2 receptor with trastuzumab (Herceptin). Trastuzumab has a proven efficacy as monotherapy as well as in combination with chemotherapeutic agents in HER-2-overexpressing metastatic breast cancer. Trastuzumab is generally well tolerated although cardiotoxicity has been observed, especially when in combination with doxorubicin (Adriamycin), where this can be a serious concern. Therefore, less cardiotoxic combinations with docetaxel (Taxotere), vinorelbine (Navelbine) and epirubicin (Pharmorubicin) or cyclophosphamide (Endoxana) have been tested. The combination of trastuzumab with paclitaxel (Taxol) is well approved. The use of trastuzumab in adjuvant and preoperative therapy is currently being examined in controlled trials. After a brief outline of immunotherapy with Theratope and trastuzumab, this article reviews recent and ongoing clinical studies conducted with trastuzumab.

Clinical applications of proton MR spectroscopy in oncology

Proton magnetic resonance spectroscopy (H1-MRS) has been increasingly receiving more attention from radiologists, neurosurgeons, radiation and medical oncologists in the "in situ" clinical evaluation of human tumors. The utilization of H1-MRS, especially in human brain tumors, coupled to both routine magnetic resonance imaging (MRI) and functional MRI techniques provides greater information concerning tumor grading and extension and characterization of the normal surrounding tissue than what is possible with any other imaging technique alone. In this paper, we will review the current status of proton MR spectroscopy with emphasis on its clinical utility to diagnose tumors, its utility in planning surgical and radiation therapy interventions, and in its use in monitoring tumor treatment.