Paolo Simoni

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). Methods WB-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. Results Strong 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. Conclusions In 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 case of a ganglion cyst in the pulp of a fifth finger in an elderly woman initially mimicking a soft tissue tumor is described. Most typical sites of ganglion cysts are well documented at the wrist and in the vicinity of inter-phalangeal and metacarpo-phalangeal joints. In this case, ultrasonography (US) and magnetic resonance imaging (MRI) demonstrated a cystic lesion within the pulp of the fifth finger and indicated carpal osteoarthritis as the distant—and unexpected—origin of the lesion. The suggested diagnosis of ganglion cyst was confirmed by computed tomography arthrography (CT arthrography) of the wrist, which showed opacification of the cyst on delayed acquisitions after intra-articular injection into the mid-carpal joint, through the fifth flexor digitorum tendon sheath. The communications between the degenerative carpal joint, the radio-ulnar bursa, the fifth flexor digitorum tendon sheath and the pedicle of the cyst were well demonstrated.

Transient osteoporosis of the hip (TOH), associated with pregnancy, is a self-limiting skeletal disorder affecting women, usually in the third trimester, which resolves spontaneously within few months postpartum. Bilateral involvement is rare. Involvement postpartum has not been described. We report three patients with postpartum presentation of bilateral TOH. Three pregnant women who presented with acute bilateral hip pain just after delivering their first child are reported. None of them had any past history of joint problems, recent injury, alcohol abuse or corticosteroid administration. Magnetic resonance (MR) imaging examinations were performed on 1.5-Tesla magnets using standard protocols. Bone marrow oedema, with normal joint space and intact articular surfaces, was depicted in all six hips. MR imaging findings with clinical correlation confirmed the diagnosis of TOH. TOH associated with pregnancy does not necessarily occur in the third trimester of pregnancy and may be bilateral.

It is the radiologist's 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.

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.

Transient osteoporosis of the hip (TOH), associated with pregnancy, is a self-limiting skeletal disorder affecting women, usually in the third trimester, which resolves spontaneously within few months postpartum. Bilateral involvement is rare. Involvement postpartum has not been described. We report three patients with postpartum presentation of bilateral TOH. Three pregnant women who presented with acute bilateral hip pain just after delivering their first child are reported. None of them had any past history of joint problems, recent injury, alcohol abuse or corticosteroid administration. Magnetic resonance (MR) imaging examinations were performed on 1.5-Tesla magnets using standard protocols. Bone marrow oedema, with normal joint space and intact articular surfaces, was depicted in all six hips. MR imaging findings with clinical correlation confirmed the diagnosis of TOH. TOH associated with pregnancy does not necessarily occur in the third trimester of pregnancy and may be bilateral.