比较全身MRI(WB-MRI)与中轴骨MRI(AS-MRI)对前列腺癌(PCa)骨转移瘤的检出与计量

目的比较全身MRI(WB-MRI)和中轴骨MRI(AS-MRI)对前列腺癌(PCa)骨转移瘤的检出与计量。方法对60例存在转移瘤高风险的PCa病人行WB-MRI和AS-     

MRI in inflammatory myopathies

Inflammatory myopathies encompass a group of acquired muscle disorders caused by infectious agents (bacteria, viruses, fungi and parasitic agents) or autoimmune processes (polymyositis, dermatomyositis and other types). In suspected infection sonography, CT and MRI are all able to show edema and fluid collections in soft tissues and muscles; sonography and CT may help guidance of a needle aspiration to establish a correct diagnosis. By offering better tissue differentiation, MRI appears to be more efficient than sonography and CT in diagnosing and managing autoimmune myopathies. MRI is indeed very sensitive to the presence of water and edema, and appears to be a very good indicator for an early diagnosis of diseases. MRI may also help to evaluate the extent and number of lesions, to guide a biopsy in an area of active disease and finally to follow the evolution under therapy. Received: 26 November 1999 Revision requested: 31 January 2000 Revision received: 7 April 2000 Accepted: 3 May 2000     

Whole-body MRI (WB-MRI) versus axial skeleton MRI (AS-MRI) to detect and measure bone metastases in prostate cancer (PCa)

Objective  

To compare whole-body MRI (WB-MRI) and axial skeleton MRI (AS-MRI) in detecting and measuring bone metastases in patients with prostate cancer (PCa).     

Whole-body MRI in the pediatric patient

Whole-body MRI is a fast and accurate modality for detection and monitoring of disease throughout the entire body. For pediatric use the technique is of special interest twofold: first it is a radiological method without radiation exposure and second it allows for whole-body staging as well as for detailed local evaluation for surgical treatment thus reducing the number of examinations to be performed in sedation. In the pediatric population the technique is used for oncological, non-oncological (i.e. fever of unknown origin, osteonecrosis) staging and for disease severity assessment of syndromes affecting the whole body. These applications will be reviewed and imaging protocols will be presented.     

Comparison of MRI sequences to detect ventriculitis

OBJECTIVE: The ability of different MRI sequences to depict characteristic findings suggestive of ventriculitis was compared. CONCLUSION: The study comprised 20 brain MRI studies in 13 patients who had a final diagnosis of ventriculitis. Both diffusion-weighted imaging and FLAIR imaging were equally and highly sensitive for detecting intraventricular debris and pus--the most common MRI finding suggestive of ventriculitis. FLAIR imaging was superior to contrast-enhanced T1-weighted imaging for depicting ventricular wall abnormalities--a less common finding that also is suggestive of ventriculitis.     

MRI findings of muscle involvement in idiopathic hypereosinophilic syndrome

A 40-year-old white man presented with fever, muscle pain, skin nodules and persistent hypereosinophilia over a period of 1 year. In addition, he had ventricular arrhythmias with episodes of tachycardia. Besides a lack of response to antiparasitic therapy, laboratory and pathological data excluded the diagnosis of trichinosis or any other parasitic infection. The patient's course of the disease over the previous 1¹/₂ years was compatible with hypereosinophilic syndrome. In a muscle biopsy several eosinophilic perivascular and leucocytic intravascular infiltrates were found, indicative of muscle involvement by the disease. This is a report on the MRI findings of muscle involvement in idiopathic hypereosinophilic syndrome. Reveived: 29 December 1997; Revision received: 9 March 1998; Accepted: 20 April 1998     

Whole-body bone marrow MRI in patients with metastatic disease to the skeletal system

PURPOSE: The purpose of this study was to evaluate the diagnostic potential of a whole-body bone marrow MR protocol in the detection of bone metastases. METHOD: Whole-body bone marrow MRI was performed in 18 patients with known malignant tumors and suspected bone metastases. The imaging protocol consisted of fast T1-weighted and STIR sequences applied in different anatomical positions covering the whole skeleton. MRI findings indicating bone metastases were compared with findings from bone scintigraphy. Metastatic lesions were confirmed by follow-up MR examinations, bone scintigraphy, radiography, or CT. RESULTS: A total number of 216 lesions were detected with MRI in comparison with 159 lesions detected with bone scintigraphy. Follow-up examinations confirmed 105 lesions. MRI detected 96 (91.4%) of the confirmed lesions, whereas bone scintigraphy detected 89 (84.8%). The entire examination, including patient positioning and changing of imaging coils, required 45 min of room time. CONCLUSION: Whole-body bone marrow MRI as used in this study is an effective method for evaluating the entire skeletal system in patients with suspected metastatic disease.     

Whole-body MRI and PET-CT in the management of cancer patients

Mortality rate, prognosis, and treatment outcome of cancer patients depend strongly on the detection of malignancy at an early stage and efficient monitoring of the disease. Multimodality diagnostic approaches are now widely applied for tumor detection, staging, and follow-up. However, the introduction of whole-body imaging modalities into clinical practice has substantially expanded diagnostic options. PET-CT has increased diagnostic accuracy by providing “anatometabolic” information by fusing tumor glucose-uptake measures from the PET examination and accurate delineation of anatomical structures given by spiral CT. Since PET-CT is associated with high doses of ionizing radiation, it is used in mainly tumor staging and screening within the scope of tertiary prevention. Here promising results have been reported for various tumor entities. MRI provides excellent tissue contrast, detailed morphological information and lack of ionizing radiation. MRI has been employed for the assessment of focal pathologies in specific anatomical regions. Whole-body MRI scanners using multiple receiver channels with parallel acquisition techniques now allow tumor screening from head to toe within substantially shorter examination times and without compromises in image resolution. We report our experience with these two novel techniques and discuss their benefits and drawbacks in terms of systemic tumor screening.     

Whole-body MRI in children: current status and future applications

Whole-body MRI (WBMRI) is a novel technique that makes imaging of the whole patient in a manner similar to scintigraphy or positron emission tomography (PET) possible. Unlike the latter two methods, it is without exposure to radiation and thus gaining increasing importance and application in pediatrics. With the introduction of a moving tabletop, sequential movement of the patient through the magnet has become possible with automatic direct realignment of the images after acquisition. The common scan plane is coronal with additional planes being added depending on the indication. WBMRI is targeted for maximum coverage of the body within the shortest possible time using the minimum number of sequences. The evaluation of the bone marrow has been the primary indication thus inversion recovery sequences like STIR or TIRM are mostly used with the T1-weighted sequence being added variably. For correct evaluation of the bone marrow in the pediatric age group understanding normal pattern of marrow transformation is essential. The primary role of WBMRI has been in oncology for the detection of tumor spread and also for the follow-up and evaluation of complications. The initial comparative studies of WBMRI with scintigraphy and PET in children have shown the high diagnostic potential of WBMRI. Emerging potential applications of WBMRI include the evaluation for osteonecrosis, chronic multifocal recurrent osteomyelitis, myopathies, and generalized vascular malformations. Future use of WBMRI may incorporate non-accidental trauma, virtual autopsy, body fat mapping and diffusion-weighted imaging.     

Whole-body MRI for primary evaluation of malignant disease in children

Objective

The aim of this study was to compare diagnostic accuracy of whole-body (WB) MRI to a combined reference standard of conventional cross-sectional imaging methods and FDG-PET in the detection of malignant disease spread in children.

Materials and methods

24 children (age between 5 and 18 years) with malignant diseases (mainly Hodgkin's lymphoma and different types of sarcoma) initially examined with conventional cross-sectional imaging methods (ultrasound, computed tomography, or magnetic resonance imaging) were examined prospectively with whole-body MRI (1.5 T) and FDG-PET. Studies were read by two nuclear medicine physicians (FDG-PET) and two radiologists (WB-MRI) independently in a blinded manner and each study type was evaluated in consensus. The reference standard was defined as pathological lesions detected in the same location both in FDG-PET and another conventional cross-sectional imaging method.

Results

Overall 190 lesions were detected by WB-MRI and 155 lesion were found by FDG-PET. 106 lesions fulfilled the criteria of the reference standard (42 osseous and 64 extraosseous lesions) from which 102 were detected by WB-MRI (sensitivity of 96%). All bone lesions were detected and extra-skeletal lesions were identified with a sensitivity of 93.8%. Overall 88 lesions detected by WB-MRI were not part of the reference standard from which 33 were lesions of the peripheral skeleton not imaged by conventional cross-sectional imaging studies. 4 lesions of the reference standard were not identified by WB-MRI which were all lymph nodes.

Conclusion

WB-MRI is a radiation free imaging technique with high sensitivity for the detection of malignant disease spread in particular beneficial for children. In patients with suspected bone lesions it should be considered for initial disease evaluation prior to specific and regional imaging methods to reduce the overall number of imaging examinations and radiation exposure.     

Whole-body MRI in neurofibromatosis: incidental findings and prevalence of scoliosis

Objective

To demonstrate incidental findings and scoliosis on whole-body MRI (WBMRI) in patients with neurofibromatosis type 1 and 2 (NF1 &; NF2, respectively), and schwannomatosis.

Materials and methods

Institutional review board approval and written informed consent were obtained for this prospective HIPAA-compliant study. A total of 247 subjects (141 with NF1, 55 with NF2, 51 with schwannomatosis; 132 women (53.5%); mean age, 41?years, range, 18–97?years) underwent WBMRI using coronal STIR (TR/TE: 4190/111?ms, TI: 150?ms) and T1-weighted images (TR/TE: 454/10?ms), 10-mm slice thickness, imaging time ~40 min. Images were reviewed for the presence of incidental findings, outside of nerve sheath tumors. The presence of scoliosis was recorded and curve morphology was assessed and quantified.

Results

Incidental findings other than scoliosis were recorded in 104/247 (42%) patients, most often affecting the musculoskeletal system (65/247 patients, 26%). We found 16/247 (6.5%) significant incidental findings likely to affect clinical management, including avascular necrosis of bone in eight patients (five with NF2), eight insufficiency fractures, and four non-neurogenic neoplasms (Hodgkin's lymphoma, liposarcoma, dermoid cyst, large uterine myoma requiring excision). Scoliosis was seen in 50/247 patients (20%), including 8/55 with NF2 (15%) and 11/51 with schwannomatosis (22%).

Conclusions

Incidental findings in the neurofibromatoses frequently involve the skeleton. Given the relatively high incidence of unsuspected osteonecrosis and stress fractures, close attention to the skeleton on WBMRI is advised. In addition, knowledge of common incidental findings can help clinicians prepare patients who undergo WBMRI for potential unexpected findings.     

Gorham syndrome of the thorax and cervical spine: CT and MRI findings

 Gorham syndrome is a rare disorder that is characterized by local osseous invasion and surrounding soft tissues by an angiomatous mass, eventually causing lysis of the affected bone. To date, only four cases have reported the MR imaging appearance of this disease and the findings have been variable. We present a case involving the cervical and thoracic spine and part of the osseous hemithorax with attention to the MR findings.     

A molecular MRI probe to detect treatment of cardiac apoptosis in vivo

Cell death by apoptosis is critical in myocardial diseases, and noninvasive detection of early, reversible apoptosis might be useful clinically. Exogenous Annexin‐V (ANX) protein binds membrane phosphatidylserine, which is externalized in early apoptosis. A molecular MRI probe was constructed with superparamagnetic iron oxide (SPIO) conjugated to recombinant human ANX (ANX‐SPIO). Apoptosis was induced with doxorubicin, a cardiotoxic cancer drug, in culture in neonatal rat ventricular myocytes, cardiac fibroblasts, and mesenchymal stem cells, and in vivo in the mouse heart. ANX‐SPIO was validated using T2*‐weighted 3T MRI. ANX‐SPIO produced T2* signal loss, reflecting iron content, that correlated highly with independent apoptosis markers; bound with high affinity to apoptotic myocytes by competition assay (Ki 69 nM); detected apoptosis in culture much earlier than did TUNEL stain; and revealed fibroblast resistance to apoptosis. With apoptosis in vivo, ANX‐SPIO produced diffuse myocardial T2* signal loss that correlated with increased iron stain and caspase activity. Treatment with an alpha‐1‐adrenergic agonist in vivo reversed apoptosis and eliminated the ANX‐SPIO MRI signal. It is concluded that cardiac MRI of ANX‐SPIO detects early, nonischemic cardiac apoptosis in culture and in vivo, and can identify reversibly injured cardiac cells in diseased hearts, when treatment is still possible. Magn Reson Med, 2011. © 2011 Wiley‐Liss, Inc.     

Whole-body MRI of multiple myeloma: comparison of different MRI sequences in assessment of different growth patterns

Purpose

To determine sensitivity, specificity and inter-observer variability of different whole-body MRI (WB-MRI) sequences in patients with multiple myeloma (MM).

Methods and materials

WB-MRI using a 1.5 T MRI scanner was performed in 23 consecutive patients (13 males, 10 females; mean age 63 ± 12 years) with histologically proven MM. All patients were clinically classified according to infiltration (low-grade, n = 7; intermediate-grade, n = 7; high-grade, n = 9) and to the staging system of Durie and Salmon PLUS (stage I, n = 12; stage II, n = 4; stage III, n = 7). The control group consisted of 36 individuals without malignancy (25 males, 11 females; mean age 57 ± 13 years). Two observers independently evaluated the following WB-MRI sequences: T1w-TSE (T1), T2w-TIRM (T2), and the combination of both sequences, including a contrast-enhanced T1w-TSE with fat-saturation (T1 ± CE/T2). They had to determine growth patterns (focal and/or diffuse) and the MRI sequence that provided the highest confidence level in depicting the MM lesions. Results were calculated on a per-patient basis.

Results

Visual detection of MM was as follows: T1, 65% (sensitivity)/85% (specificity); T2, 76%/81%; T1 ± CE/T2, 67%/88%. Inter-observer variability was as follows: T1, 0.3; T2, 0.55; T1 ± CE/T2, 0.55. Sensitivity improved depending on infiltration grade (T1: 1 = 60%; 2 = 36%; 3 = 83%; T2: 1 = 70%; 2 = 71%; 3 = 89%; T1 ± CE/T2: 1 = 50%; 2 = 50%; 3 = 89%) and clinical stage (T1: 1 = 58%; 2 = 63%; 3 = 79%; T2: 1 = 58%; 2 = 88%; 3 = 100%; T1 ± CE/T2: 1 = 50%; 2 = 63%; 3 = 100%). T2w-TIRM sequences achieved the best reliability in depicting the MM lesions (65% in the mean of both readers).

Conclusions

T2w-TIRM sequences achieved the highest level of sensitivity and best reliability, and thus might be valuable for initial assessment of MM. For an exact staging and grading the examination protocol should encompass unenhanced and enhanced T1w-MRI sequences, in addition to T2w-TIRM.