Correlative bone imaging in a case of Schnitzler's syndrome and brief review of the literature.

UNLABELLED: Schnitzler's syndrome is a rare disease characterized by a monoclonal IgM (or IgG) paraprotein, a nonpruritic urticarial skin rash, and 2 (or 3) of the following: recurrent fever, objective signs of abnormal bone remodeling, elevated CRP level or leukocytosis, and a neutrophilic infiltrate on skin biopsy. It responds well to treatment with the interleukine-1-inhibitor anakinra. We report the bone scintigraphy and MRI findings in a 45 years old man with this syndrome and compare them with data from the literature. CONCLUSION: None of the imaging findings are specific, but they lead to a differential diagnosis including infiltrative diseases (e.g. systemic mastocytosis or Erdheim-Chester disease) and dysplastic diseases (e.g. melorheostosis, Camurati-Engelmann disease or van Buchem disease). The bone scintigraphy pattern may be very suggestive of the correct diagnosis and of bone involvement in this syndrome.

Corpus Cavernosum Abscess Diagnosed on FDG PET/CT.

The utility of PET in septicemia for showing its source and possible metastatic infection has been demonstrated. We describe the diagnosis on PET/CT of a spontaneous corpus cavernosum abscess in a 64-year-old man presenting with Streptococcus constellatus septicemia, in whom the clinical diagnosis had been elusive for 10 days.

Comparison of the prognostic value of dipyridamole and dobutamine myocardial perfusion scintigraphy in hemodialysis patients.

Screening for coronary artery disease (CAD) in hemodialysis patients is hampered by contraindications and/or limitations of the available techniques in this population. Myocardial perfusion scintigraphy (MPS) using dipyridamole has been considered inaccurate due to abnormally high basal levels of adenosine in uremia that could blunt the vasodilatory response. Since dobutamine may be more reliable, we directly compared the two in patients on hemodialysis. We performed MPS at rest and after separate dipyridamole or dobutamine stress in 121 chronic hemodialysis patients. More numerous, larger, and more intense reversible lesions were induced with dobutamine than with dipyridamole, mainly in the anteroseptal segments. Reversibility with dipyridamole but not dobutamine MPS was independently and strongly related with mortality associated with CAD and with fatal and non-fatal CAD. We hypothesize that the chronotropic action of dobutamine induced alterations of wall motion, leading to spurious perfusion defects, not unlike artifacts seen with left bundle branch block. Our study shows that even though dobutamine induced more pronounced myocardial ischemia than dipyridamole in chronic hemodialysis patients, dipyridamole MPS more accurately identifies patients at high risk for subsequent cardiac death or non-fatal CAD than dobutamine.

Comparison of MRI (including SS SE-EPI and SPIO-enhanced MRI) and FDG-PET/CT for the detection of colorectal liver metastases.

Fluoro-18-deoxyglucose positron emission tomography computed tomography (FDG-PET/CT) and magnetic resonance imaging (MRI), including unenhanced single-shot spin-echo echo planar imaging (SS SE-EPI) and small paramagnetic iron oxide (SPIO) enhancement, were compared prospectively for detecting colorectal liver metastases. Twenty-four consecutive patients suspected for metastases underwent MRI and FDG-PET/CT. Fourteen patients (58%) had previously received chemotherapy, including seven patients whose chemotherapy was still continuing to within 1 month of the PET/CT study. The mean interval between PET/CT and MRI was 10.2+/-5.2 days. Histopathology (n=18) or follow-up imaging (n=6) were used as reference. Seventy-seven metastases were detected. In nine patients, MRI and PET/CT gave concordant results. Sensitivities for unenhanced SS SE-EPI, MRI without SS SE-EPI and FDG-PET/CT were, respectively, 100% (p=9 x 10(-10) vs PET, p=8 x 10(-3) vs MRI without SS SE-EPI), 90% (p=2 x 10(-7) vs PET) and 60%. PET/CT sensitivity dropped significantly with decreasing size, from 100% in lesions larger than 20 mm (identical to MRI), over 54% in lesions between 10 and 20 mm (p=3 x 10(5) versus unenhanced SS SE-EPI), to 32% in lesions under 10 mm (p=6 x 10(-5) versus unenhanced SS SE-EPI). Positive predictive value of PET was 100% (identical to MRI). MRI, particularly unenhanced SS SE-EPI, has good sensitivity and positive predictive value for detecting liver metastases from colorectal carcinoma. Its sensitivity is better than that of FDG-PET/CT, especially for small lesions.

Bone scan findings in calcific tendinitis at the gluteus maximus insertion: some illustrative cases.

We describe the bone scan and single-photon emission computed tomography/computed tomography findings in calcific tendinitis of the gluteus maximus and discuss its pathophysiology. Although this tendinopathy is mostly self-limiting, awareness of this disease is important for 2 reasons. First, it may explain acute hip symptoms in patients in the resorptive phase of the calcifications. Second, it should be considered as a differential diagnosis for bone scan hot spots in the vicinity of the gluteus maximus tendon and for cortical erosion seen in that region on X-rays or CT.