Rectal imaging: part 1, High-resolution MRI of carcinoma of the rectum at 3 T

OBJECTIVE: MRI is currently the imaging modality of choice for the detection, characterization, and staging of rectal cancer. A variety of examinations have been used for preoperative staging of rectal cancer, including digital rectal examination, endorectal (endoscopic) ultrasound, CT, and MRI. Endoscopic ultrasound is the imaging modality of choice for small and small superficial tumors. MRI is superior to CT for assessing invasion to adjacent organs and structures, especially low tumors that carry a high risk of recurrence. CONCLUSION: High-resolution MRI is an accurate and sensitive imaging method delineating tumoral margins, mesorectal involvement, nodes, and distant metastasis. In this article, we will review the utility of rectal MRI in local staging, preoperative evaluation, and surgical planning. MRI at 3 T can accurately delineate the mesorectal fascia involvement, which is one of the main decision points in planning treatment.     

Bildgebende Diagnostik im Staging gynäkologischer Karzinome

The prognosis in patients with gynecologic cancers depends not only on the stage but also on a wide spectrum of other findings. Cross-sectional imaging modalities, including sonography, CT and MRI, have increasingly been used for optimal treatment planning in gynecologic cancers. Their staging criteria are based on the well-established FIGO staging system. CT and MRI compete with sonography, which plays a pivotal role in the evaluation of the female pelvis. This paper reviews the role of sonography, CT and MRI in the staging of gynecologic malignancies. It puts the emphasis on MRI, which has been established as imaging modality of choice in the preoperative evaluation of cervical and endometrial cancer, and which seems slightly superior to CT in the staging of ovarian cancer.     

Zervixkarzinom

The treatment of uterine cervical carcinoma is largely dependent on the tumor stage. Despite significant inaccuracies in the clinical examination, uterine cervical cancer remains the only gynecological form of cancer still largely staged according to clinical findings. Although imaging is still not included in the staging the recently published revised FIGO (Fédération International de Gynécologie et d'Obstétrique) system encourages the use of modern cross-sectional imaging (magnetic resonance imaging MRI and computed tomography CT). Due to its high soft tissue contrast MRI allows excellent non-invasive assessment of the cervix with direct tumor delineation as well as assessment of the prognosis based on morphological factors. Studies in the literature report an accuracy of 93% for MRI in the preoperative assessment of tumor size and in the differentiation of operable from advanced cervical cancer. Therefore MRI is considered to be the optimal modality for diagnostic evaluation starting from FIGO stage IB1, for radiation therapy planning, and for exclusion of recurrence in follow-up. In this paper we give an overview of the role of magnetic resonance imaging in preoperative staging of uterine cervical cancer.     

Utility of positron emission tomography-magnetic resonance imaging in musculoskeletal imaging

Differentiation between neoplastic and nonneoplastic conditions magnetic resonance imaging (MRI) has established itself as one of the key clinical tools in evaluation of musculoskeletal pathology. However, MRI still has several key limitations which require supplemental information from additional modalities to complete evaluation of various disorders. This has led to the development hybrid positron emission tomography (PET)-MRI which is rapidly evolving to address key clinical questions by using the morphological strengths of MRI and functional information of PET imaging. In this article, we aim to review physical principles and techniques of PET-MRI and discuss clinical utility of functional information obtained from PET imaging and structural information obtained from MRI imaging for the evaluation of musculoskeletal pathology. More specifically, this review highlights the role of PET-MRI in musculoskeletal oncology including initial diagnosis and staging, treatment planning and post-treatment follow-up. Also we will review utility of PET-MRI in evaluating musculoskeletal infections (especially in the immunocompromised and diabetics) and inflammatory condition. Additionally, common pitfalls of PET-MRI will be addressed.     

Relevance of magnetic resonance imaging for the staging and follow up of lymph node pathologies in adults with primary malignant lymphomas

Lymph node histology and staging with cross sectional imaging remains basis for the treatment planning in primary malignant lymphoma. Contrast enhanced computed tomography is considered to be gold standard. However, MRI is equally able to provide staging and follow up in the same quality as helical CT, as several studies and clinical experience show. MRI is considered as the superior imaging modality for extranodal lymphoma. Advantages of MRI are that it works without ionizing radiation and contrast media;however, MRI is more expensive and time consuming. However, both imaging modalities are limited by the fact that the differentiation of affected and non affected lymph nodes is based on size only.Also the results of recent clinical studies with USPIOs (SINEREM((R):)) for intravenous MR lymphography in primary malignant lymphoma do not look promising. Despite these disadvantages of MRI, for young patients with malignant lymphoma radiation protection should be taken into account because of frequent imaging in staging and follow up.     

Anal carcinomas: the role of endoanal ultrasound and magnetic resonance imaging in staging, response evaluation and follow-up

Anal carcinoma is an important but rare condition, managed in specialist centres. Both endoanal ultrasound and magnetic resonance imaging (MRI) can be used in the locoregional staging and follow-up of patients with anal cancer, and both may assist in treatment planning and prognosis. Recent guidelines published by the European Society for Medical Oncology have recommended MRI as the technique of choice for assessment of locoregional disease. This paper describes the techniques for both endoanal ultrasound and MRI, and compares the relative merits and disadvantages of each in the local assessment of anal carcinoma.     

Imaging of the larynx and hypopharynx

The purpose of this article is to review currently used imaging protocols for the evaluation of pathologic conditions of the larynx and hypopharynx, to describe key anatomic structures in the larynx and hypopharynx that are relevant to tumor spread and to discuss the clinical role of Computed Tomography (CT), Magnetic Resonance Imaging (MRI) and PET CT in the pretherapeutic workup and posttherapeutic follow-up of patients with squamous cell carcinoma of this region. A detailed discussion of the characteristic neoplastic submucosal invasion patterns, including extension to the preepiglottic space, paraglottic space and laryngeal cartilages and the implications of imaging for tumor staging and treatment planning is provided. The present article also reviews less common tumors of this region, such as chondrosarcoma, lymphoma, minor salivary gland tumors and lipoma. As the majority of non-neoplastic conditions do not require imaging the role of CT and MRI is discussed in some particular situations, such as to delineate cysts and laryngoceles, abscess formation in inflammatory conditions, to evaluate laryngeal and hypopharyngeal involvement in granulomatous and autoimmune diseases, and to evaluate the extent of laryngeal fractures due to severe blunt trauma.     

Invited. Cervical cancer

The stage estimated by clinical FIGO staging is the main determinant in guiding the treatment decisions. However, clinical FIGO staging does have inherent inaccuracies, because it does not include significant prognostic factors. Presently, MRI is not officially incorporated in the staging workup system; however, it is widely accepted as the most reliable imaging modality in evaluating cervical cancer and in treatment planning. MRI offers direct tumor visualization, accurate assessment of the depth of stromal invasion and tumor volume, lymph node evaluation, and reliable staging accuracy. Published reports show the superiority of MRI over clinical staging, and several recent works on dynamic MRI suggest further improvement of MRI in evaluating cervical cancer.     

Imaging of ovarian cancer

Cross sectional imaging continues to play an increasingly important role in ovarian cancer diagnosis, staging, and treatment follow-up. Screening for ovarian cancer remains a controversial subject. The combined use of clinical examination, CA-125, and endovaginal ultrasound (US) are being advocated for high risk patients but consensus recommendation for screening awaits further studies. in characterization of an ovarian neoplasm US is indisputedly the primary imaging approach. Only when US is inconclusive are further studies warranted. Magnetic resonance imaging (MRI) is generally preferred to computer tomography (CT). A prospective MRI-CT clinical trial has not been performed as yet. Preoperative staging by imaging is slowly gaining its acceptance. This is mostly due to the awareness of the difficulties and inaccuracy in surgical staging when unsuspected extensive disease is present. Furthermore, in known resectable ovarian cancer, primary chemotherapeutic cytoreduction may be a better treatment option. Accuracy of CT and MRI in staging ovarian cancer is similar. CT, however, is faster, more widely available, and less expensive; these are important attributes that are decisive in this time of health reimbursement constraints.     

Role of MRI in the management of patients with nephroblastoma

Magnetic resonance imaging (MRI) presents the main diagnostic tool for differentiation and staging of renal tumors in childhood. Nephroblastoma is the most common malignant tumor in children. Radiological findings play an important role in therapy study trials of SIOP (International Society of Pediatric Oncology), especially for indicating preoperative chemotherapy. In the past few years MRI has gained great importance in imaging of nephroblastoma and has replaced computed tomography (CT). The aim of this review is to present the diagnostic possibilities of MRI in relation to the requirements of therapy studies. For nephroblastoma, MRI provides important information about tumor extent and distant metastasis. A special focus of MRI in distant staging is venous extent of the tumor into the inferior vena cava. In addition, MRI has an important role in monitoring chemotherapy and in preoperative planning by volume rendering and three-dimensional postprocessing.     

Staging of uterine cervical cancer with MRI: guidelines of the European Society of Urogenital Radiology

Objective: To design clear guidelines for the staging and follow-up of patients with uterine cervical cancer, and to provide the radiologist with a framework for use in multidisciplinary conferences. Methods: Guidelines for uterine cervical cancer staging and follow-up were defined by the female imaging subcommittee of the ESUR (European Society of Urogenital Radiology) based on the expert consensus of imaging protocols of 11 leading institutions and a critical review of the literature. Results: The results indicated that high field Magnetic Resonance Imaging (MRI) should include at least two T2-weighted sequences in sagittal, axial oblique or coronal oblique orientation (short and long axis of the uterine cervix) of the pelvic content. Axial T1-weighted sequence is useful to detect suspicious pelvic and abdominal lymph nodes, and images from symphysis to the left renal vein are required. The intravenous administration of Gadolinium-chelates is optional but is often required for small lesions (<2 cm) and for follow-up after treatment. Diffusion-weighted sequences are optional but are recommended to help evaluate lymph nodes and to detect a residual lesion after chemoradiotherapy. Conclusions: Expert consensus and literature review lead to an optimized MRI protocol to stage uterine cervical cancer. MRI is the imaging modality of choice for preoperative staging and follow-up in patients with uterine cervical cancer.     

Imaging of bone tumors for the musculoskeletal oncologic surgeon

The appropriate diagnosis and treatment of bone tumors requires close collaboration between different medical specialists. Imaging plays a key role throughout the process. Radiographic detection of a bone tumor is usually not challenging. Accurate diagnosis is often possible from physical examination, history, and standard radiographs. The location of the lesion in the bone and the skeleton, its size and margins, the presence and type of periosteal reaction, and any mineralization all help determine diagnosis. Other imaging modalities contribute to the formation of a diagnosis but are more critical for staging, evaluation of response to treatment, surgical planning, and follow-up.When necessary, biopsy is often radioguided, and should be performed in consultation with the surgeon performing the definitive operative procedure. CT is optimal for characterization of the bone involvement and for evaluation of pulmonary metastases. MRI is highly accurate in determining the intraosseous extent of tumor and for assessing soft tissue, joint, and vascular involvement. FDG-PET imaging is becoming increasingly useful for the staging of tumors, assessing response to neoadjuvant treatment, and detecting relapses.Refinement of these and other imaging modalities and the development of new technologies such as image fusion for computer-navigated bone tumor surgery will help surgeons produce a detailed and reliable preoperative plan, especially in challenging sites such as the pelvis and spine.     

Imaging of abdominal nodal spread in malignant disease

This is a review of the role of imaging procedures for the assessment of abdominal and pelvic lymph nodes. The diagnosis of malignant lymphatic spread is rarely the sole purpose of imaging, because it is usually part of a general abdominal examination, most frequently with CT or US, or increasingly with MRI. These studies are often requested in order to obtain information about the situation to be encountered during surgery, or to alert the surgeon to irresectability or to unexpected metastases outside the initially planned area of exploration. In most surgically treated tumours the role of imaging for preoperative staging is limited, due either to its insufficient sensitivity or because the initial treatment is independent of the lymph node stage. Imaging is commonly used to verify treatment response to chemo- or radiotherapy and for follow-up.Correspondence to: S. Delorme     

A comparison of modern imaging modalities in osteonecrosis of the femoral head

Eleven symptomatic and seven asymptomatic patients, considered to be at high risk of osteonecrosis of the hip, were studied using plain radiography, scintigraphy, computed tomography (CT) with multiplanar reconstruction (MPR), and magnetic resonance imaging (MRI), to determine the precise roles of the various imaging modalities in detecting and staging femoral head osteonecrosis, and to evaluate the incidence in an asymptomatic high-risk patient group. Osteonecrosis was best detected by MRI and was particularly useful for the diagnosis of early disease when other imaging modalities were negative. It is recommended that MRI be performed for the detection of early osteonecrosis, while CT/MPR be used for accurate staging and treatment planning in the established disease.     

Management of cervical cancer detected during pregnancy: role of magnetic resonance imaging

ObjectiveThe aims of the present study were to assess the role of magnetic resonance imaging (MRI) in the staging and follow-up of uterine cervical cancers discovered during pregnancy and to evaluate the role of MRI in decision making regarding treatment options for patients with uterine cervical cancer during pregnancy.MethodTwelve pregnant women with cervical cancer were included. Two populations of patients were distinguished: localized cervical cancer discovered on the Pap smear during the first trimester of pregnancy, at an early stage (n=5), and invasive cervical cancer revealed later, during the second or third trimester (n=7). Abdominal and pelvic MRI sequences were acquired with a phased-array coil. Magnetic resonance results were correlated with the physical examination, Pap smear, and pathology.ResultsIn the first population, MRI was normal or detected a small lesion (stage IB1), and pregnancies were allowed to continue. In the second population, MRI detected a lesion in every case (mean size, 62 mm; 30–110 mm), and positive lymph nodes were depicted in 2 cases. The pregnancy was interrupted in four patients: one interruption in localized cervical cancer group and three in invasive cervical group). In all other cases, a cesarean section was done after the 30th week. In one case, MRI assessed response after chemotherapy administered during pregnancy.ConclusionMRI is an essential examination for planning the treatment of cervical cancers diagnosed during pregnancy.     

Imaging of cancer of the uterine cervix

Recently, magnetic resonance imaging (MRI) and transrectal or transvaginal ultrasound (TRUS, TVUS) had an important place in imaging techniques of cervical carcinomas and raise the question of modifying the imaging strategies. For the diagnosis of primitive tumor, those techniques cannot take the place of clinical examination and gross examination. In the assessment of parametrial involvement, TRUS which has better accuracy than clinical examination, and MRI which is considered as the most accurate technique, have an important role to play. In the follow-up and the detection of recurrences, MRI is actually considered as the best imaging technique. The authors, according to recent data in literature and their own experience, present basic concepts of imaging strategies for staging and follow-up of cervical carcinomas.     

Comparison of <Superscript>18</Superscript>F-FDG PET/MRI and MRI for pre-therapeutic tumor staging of patients with primary cancer of the uterine cervix

Purpose

The aim of the present study was to assess and compare the diagnostic performance of integrated PET/MRI and MRI alone for local tumor evaluation and whole-body tumor staging of primary cervical cancers. In addition, the corresponding impact on further patient management of the two imaging modalities was assessed.

Methods

A total of 53 consecutive patients with histopathological verification of a primary cervical cancer were prospectively enrolled for a whole-body 18F-FDG PET/MRI examination. Two experienced physicians analyzed the MRI data, in consensus, followed by a second reading session of the PET/MRI datasets. The readers were asked to perform a dedicated TNM staging in accordance with the 7th edition of the AJCC staging manual. Subsequently, the results of MRI and PET/MRI were discussed in a simulated interdisciplinary tumor board and therapeutic decisions based on both imaging modalities were recorded. Results from histopathology and cross-sectional imaging follow-up served as the reference standard.

Results

PET/MRI allowed for a correct determination of the T stage in 45/53 (85%) cases, while MRI alone enabled a correct identification of the tumor stage in 46/53 (87%) cases. In 24 of the 53 patients, lymph node metastases were present. For the detection of nodal-positive patients, sensitivity, specificity and accuracy of PET/MRI were 83%, 90% and 87%, respectively. The respective values for MRI alone were 71%, 83% and 77%. In addition, PET/MRI showed higher values for the detection of distant metastases than MRI alone (sensitivity: 87% vs. 67%, specificity: 92% vs. 90%, diagnostic accuracy: 91% vs. 83%). Among the patients with discrepant staging results in the two imaging modalities, PET/MRI enabled correct treatment recommendations for a higher number (n = 9) of patients than MRI alone (n = 3).

Conclusion

The present results demonstrate the successful application of integrated PET/MRI imaging for whole-body tumor staging of cervical cancer patients, enabling improved treatment planning when compared to MRI alone.

     

The role of MRI in image-guided needle biopsy of focal bone and soft tissue neoplasms

Magnetic resonance imaging (MRI) plays a critical role in the management pathway of both soft tissue and bone neoplasms, from diagnosis through to post-treatment follow-up. There are a wide range of surgical, oncological, and combined treatment regimes but these rely on accurate histopathological diagnosis. This article reviews the role of MRI in the planning of image-guided needle biopsy for suspected soft tissue and bone tumors.     

Stellenwert der PET/CT zur Bildgebung des kolorektalen Karzinoms

CLINICAL/METHODICAL ISSUE: Fluorodeoxyglucose-positron emission tomography/computed tomography (FDG-PET/CT) has emerged as a very useful imaging modality in the management of colorectal carcinoma. Data from the literature regarding the role of PET/CT in the initial diagnosis, staging, radiotherapy planning, response monitoring and surveillance of colorectal carcinoma is presented. Future directions and economic aspects are discussed. STANDARD RADIOLOGICAL METHODS: Computed tomography (CT), magnetic resonance imaging (MRI) and FDG-PET for colorectal cancer and endorectal ultrasound for rectal cancer. METHODICAL INNOVATIONS: Combined FDG-PET/CT. PERFORMANCE: While other imaging modalities allow superior visualization of the extent and invasion depth of the primary tumor, PET/CT is most sensitive for the detection of distant metastases of colorectal cancer. ACHIEVEMENTS: We recommend a targeted use of PET/CT in cases of unclear M staging, prior to metastasectomy and in suspected cases of residual or recurrent colorectal carcinoma with equivocal conventional imaging. The role of PET/CT in radiotherapy planning and response monitoring needs to be determined. Currently there is no evidence to support the routine use of PET/CT for colorectal screening, staging or surveillance. PRACTICAL RECOMMENDATIONS: To optimally exploit the synergy between morphologic and functional information, FDG-PET should generally be performed as an integrated FDG-PET/CT with a contrast-enhanced CT component in colorectal carcinoma.     

Nasopharyngeal carcinoma: the impact of CT-scan and of MRI on staging, radiotherapy treatment planning, and outcome of the disease

The present study is a critical review of the role of computed tomography (CT) and magnetic resonance imaging (MRI) in the diagnosis and therapy of nasopharyngeal cancer. It is estimated that following CT-scan/MRI, T,N staging of the disease changes in about half of cases, which results in important adjustments of the radiotherapy treatment planning, both in terms of radiation field dimensions and of dose specifications. The development of novel technology with CT-scan-simulated 3-D conformal or intensity-modulated radiotherapy (IMRT) planning is gradually becoming the standard therapy for nasopharyngeal carcinoma (NPC). CT-scan/MRI is also of value in detecting massive parapharyngeal involvement, low-neck lymphadenopathy or fixation of nodes onto adjacent structures, which are important features indicating the necessity to integrate chemotherapy or surgical neck dissection in the overall treatment policy. CT-positron emission tomography (PET) scan is recently under evaluation for the identification of the most active tumor regions, which will allow a biological radiotherapy planning (RTP) using IMRT techniques.