Paolo Simoni

Multidetector spiral CT arthrography of the shoulder. Clinical applications and limits, with MR arthrography and arthroscopic correlations

Although MR imaging and MR arthrography are the first choice modalities for shoulder imaging, CT arthrography (CTA) may be used successfully to address many clinical questions. The advent of submillimeter multiple detector CT technology and subsequent excellent three-plane resolution has considerably increased the quality of CTA examinations and has propelled this technique to the forefront in a growing number of indications. The combined use of iodinated contrast material for fluoroscopic confirmation of the articular position of the needle before injection of gadolinium chelates for MR arthrography offers the unique opportunity to compare CTA and MRA findings in carefully selected cases. This paper illustrates capabilities and limits of CTA for the study of rotator cuff tears, shoulder instability, cartilage lesions, anatomical variants and abnormalities of the glenoid labrum, with correlations to MR arthrography and surgical findings.

CT Arthrography, MR Arthrography, PET, and Scintigraphy in Osteoarthritis

CT arthrography and MR arthrography are accurate methods for the study of surface cartilage lesions and cartilage loss. They also provide information on subchondral bone and marrow changes, and ligaments and meniscal lesions that can be associated with osteoarthritis. Nuclear medicine also offers new insights in the assessment of the disease. This article discusses the strengths and limitations of CT arthrography and MR arthrography. It also highlights nuclear medicine methods that may be relevant to the study of osteoarthritis in research and clinical practice.

Bone marrow edema of the femoral head and transient osteoporosis of the hip.

The current article of this issue aims at defining the generic term of bone marrow edema of the femoral head as seen at MR imaging. It must be kept in mind that this syndrome should be regarded, not as a specific diagnosis, but rather as a sign of an ongoing abnormal process that involves the femoral head and/or the hip joint. We aim at emphasizing the role of the radiologists in making a specific diagnosis, starting from a non-specific finding on T1-weighted images and by focusing on ancillary findings on T2-weighted SE or fat-saturated proton-density weighted MR images.

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

ObjectiveTo compare whole-body MRI (WB-MRI) and axial skeleton MRI (AS-MRI) in detecting and measuring bone metastases in patients with prostate cancer (PCa).MethodsWB-MRI and AS-MRI examinations were performed in 60 patients with PCa at high risk of metastases. Two radiologists separately categorised the AS-MRI and WB-MRI as negative or positive for metastases, and measured focal metastases using the “Response evaluation criteria in solid tumours” (RECIST) criteria transposed to bone. One radiologist reviewed all examinations 2 months later. Inter- and intraobserver agreements in establishing the presence/absence of metastases were calculated. Bland-Altman plots were used to assess measurement agreement between AS-MRI and WB-MRI.ResultsStrong to perfect inter- and intraobserver agreements were found between AS-MRI and WB-MRI in defining the presence/absence of bone metastases. There were no patients with isolated “peripheral” metastases at WB-MRI, missed at AS-MRI. There was no difference in lesion count between the two radiologists. AS-MRI and WB-MRI provided statistically equivalent RECIST values for one radiologist and slightly lower values at AS-MRI for the other.ConclusionsIn our series of PCa patients, AS-MRI and WB-MRI were equivalent in determining the presence/absence of bone metastases and provided similar evaluation of the metastatic burden.

The role of positron emission tomography-computed tomography and magnetic resonance imaging in diagnosis and follow-up of multiple myeloma

Multiple myeloma is the second most common hematologic malignancy and occurs most commonly in elderly patients. Almost all multiple myeloma patients develop bone lesions in the course of their disease or have evidence of bone loss at initial diagnosis. Whole-body conventional radiography remains the gold standard in the diagnostic evaluation, but computed tomography, magnetic resonance imaging and 18F-fluorodeoxyglucose positron emission tomography are increasingly used as complementary techniques in the detection of bone lesions. Moreover, the number of lesions detected and the presence of extramedullary disease give strong prognostic information. These new techniques may help to assess treatment response in solitary plasmacytoma or in multiple myeloma. In this article, we review recent data on the different imaging techniques used at diagnosis and in the assessment of treatment response, and discuss some current issues.

Recommendations of the ESSR Arthritis Subcommittee for the Use of Magnetic Resonance Imaging in Musculoskeletal Rheumatic Diseases.

This article presents the recommendations of the European Society of Musculoskeletal Radiology Arthritis Subcommittee regarding the standards of the use of MRI in the diagnosis of musculoskeletal rheumatic diseases. The recommendations discuss (1) the role of MRI in current classification criteria of musculoskeletal rheumatic diseases (including early diagnosis of inflammation, disease follow-up, and identification of disease complications); (2) the impact of MRI on the diagnosis of axial and peripheral spondyloarthritis, rheumatoid arthritis, and juvenile spondyloarthritis; (3) MRI protocols for the axial and peripheral joints; (4) MRI interpretation and reporting for axial and peripheral joints; and finally, (5) methods for assessing MR images including quantitative, semiquantitative, and dynamic contrast-enhanced MRI studies.

Diffusion-weighted MR Imaging: Adjunct or Alternative to T1-weighted MR Imaging for Prostate Carcinoma Bone Metastases?

Editor: We read with interest the article by Dr Luboldt and colleagues in the December 2008 issue of Radiology, which proposed diffusion-weighted (DW) imaging as an alternative to conventional magnetic resonance (MR) sequences and carbon 11 (C)-choline positron emission tomography (PET)/computed tomography (CT) for the detection of bone metastases in patients with prostate carcinoma (1). The suggestion is backed by their series of 11 patients with prostate carcinoma, in which all 15 bone metastases of the pelvis that were detected at Ccholine PET/CT were also visible on short inversion time inversion recovery (STIR) and DW MR images, while a lesion of the iliac bone was a false-negative finding on T1-weighted images. That single falsenegative lesion is shown in figure 3. That image, although stated to be T1weighted, is clearly T2-weighted, as demonstrated by the high signal intensity of the cerebrospinal fluid. We wonder if this lesion was really occult on true T1weighted images. More surprisingly, a second lesion (in the left acetabulum) that was a false-negative finding on T1weighted images is shown in figure 4 but is not mentioned in the results. This second false-negative lesion was only visible on STIR and DW images; it was occult on the corresponding reference standard (PET/CT). This raises questions about the relevance of that lesion, which could be, for example, subchondral bone marrow edema. In our ongoing study of more than 120 patients with prostate carcinoma who were screened with a whole-body MR protocol (including T1-weighted, STIR, and DW sequences) for bone metastases, we observed a substantial number of false-negative and false-positive findings at DW imaging that were better characterized at T1-weighted imaging. Our early data parallel those of others (2,3), who recommended the use of conventional sequences to substantiate abnormal DW findings. Which sequence (T1-weighted, T2-weighted, or STIR) should be added to DW imaging for a confident diagnosis remains to be established. We share the authors’ enthusiasm for DW imaging and believe that MR imaging will become a widely accepted alternative to bone scans or PET/CT for the work-up of bone metastases in patients with prostate carcinoma (4,5). Nevertheless, we suggest evaluation of the accuracy of DW imaging for depicting bone metastases in a larger population before abandoning traditional sequences (eg, T1-weighted).

Value of computed tomography arthrography with delayed acquisitions in the work-up of ganglion cysts of the tarsal tunnel: report of three cases

Ganglion cysts are a common cause of tarsal tunnel syndrome. As in other locations, these cysts are believed to communicate with neighboring joints. The positive diagnosis and preoperative work-up of these cysts require identification and location of the cyst pedicles so that they may be excised and the risk of recurrence decreased. This can be challenging with ultrasonography and magnetic resonance (MR) imaging. We present three cases of symptomatic ganglion cysts of the tarsal tunnel, diagnosed by MR imaging, where computed tomography (CT) arthrography with delayed acquisitions helped to confirm the diagnosis and identify precisely the topography of the communication with the subtalar joint. These cases provide new evidence of the articular origin of ganglion cysts developing in the tarsal tunnel.

Normal Variants of the Bone Marrow at MR Imaging of the Spine.

It is the radiologists cornerstone to decide if imaging findings are normal or abnormal and to differentiate between clinically significant and insignificant findings. This challenge is extremely common in routine clinical practice when performing magnetic resonance (MR) imaging of the spine because it is frequently performed to assess patients with cancer or with spine-related symptoms. MR appearance of the normal vertebral marrow shows important variations not only with age but also among individuals of the same age range. On the contrary, marrow distribution and signal intensity patterns show little variation among each vertebral body of the same subject. Focal alterations in signal intensity can be observed that reflect local variation in the amount of normal expected vertebral components, including fat and hematopoietic cells, bone, and vessels. A more recently recognized condition related to the presence of notochordal cells deserves further study because it could account for some frequent tiny marrow changes. Diffuse alteration in vertebral signal intensity can also be observed and can be difficult--or even impossible--to differentiate from diffuse marrow infiltration by an abnormal process, given the lack of specificity of MR imaging. This article highlights the normal variants and frequent alterations of the vertebral bone marrow as encountered on MR studies of the spine and that can simulate significant lesions.

Evaluation of DCE-MRI postprocessing techniques to assess metastatic bone marrow in patients with prostate cancer

Dynamic contrast-enhanced magnetic resonance imaging was performed in control patients with normal bone marrow and patients with untreated bone metastases of prostate cancer (PCa). Perfusion data were assessed using region of interest-based and pixel-wise current standard postprocessing techniques (signal intensity pattern, increase in signal intensity, upslope, time to peak, extended Kety model, k-means clustering). Bone marrow perfusion is significantly increased in bone metastases of PCa compared to normal bone marrow. Pixel-wise kinetic modeling should be recommended to assess tumoral processes affecting bone marrow microcirculation.