Impact of attenuation correction on clinical [(18)F]FDG brain PET in combined PET/MRI.

BACKGROUND: In PET/MRI, linear photon attenuation coefficients for attenuation correction (AC) cannot be directly derived, and cortical bone is, so far, usually not considered. This results in an underestimation of the average PET signal in PET/MRI. Recently introduced MR-AC methods predicting bone information from anatomic MRI or proton density-weighted zero-time imaging may solve this problem in the future. However, there is an ongoing debate if the current error is acceptable for clinical use and/or research. METHODS: We examined this feature for [(18)F] fluorodeoxyglucose (FDG) brain PET in 13 patients with clinical signs of dementia or movement disorders who subsequently underwent PET/CT and PET/MRI on the same day. Multiple MR-AC approaches including a CT-derived AC were applied. RESULTS: The resulting PET data was compared to the CT-derived standard regarding the quantification error and its clinical impact. On a quantitative level, -11.9 to +2 % deviations from the CT-AC standard were found. These deviations, however, did not translate into a systematic diagnostic error. This, as overall patterns of hypometabolism (which are decisive for clinical diagnostics), remained largely unchanged. CONCLUSIONS: Despite a quantitative error by the omission of bone in MR-AC, clinical quality of brain [(18)F]FDG is not relevantly affected. Thus, brain [(18)F]FDG PET can already, even now with suboptimal MR-AC, be utilized for clinical routine purposes, even though the MR-AC warrants improvement.

[Cardiac fibromyxosarcoma with bone metastases : palliative surgical treatment]. / Ossär metastasierendes Fibromyxosarkom des Herzens : Palliative operative Therapie.

This article presents the unusual case of a 58-year-old woman with a low-grade cardiac fibromyxosarcoma which was primarily surgically resected and treated with adjuvant chemotherapy. A pulmonary metastasis as well as osteolytic metastatic destruction of the right iliac crest occurred 3 years after primary diagnosis and 2 years later a bone metastasis of the left distal femur was detected. Applying a palliative treatment concept resection of the pulmonary metastasis and an extralesional resection of the bone metastasis of the right iliac crest with plastic reconstruction were performed. Afterwards resection of the left distal femur metastasis and prosthetic reconstruction with distal femur replacement could also be realized. Despite an initial poor prognosis a high quality of life without essential functional limitations could be maintained for more than 6 years in this individual case.

Radioligand imaging of α4ß2* nicotinic acetylcholine receptors in Alzheimer's disease and Parkinson's disease.

The α4ß2* nicotinic acetylcholine receptors (α4ß2*-nAChR) are highly abundant in the human brain. As neuromodulators they play an important role in cognitive functions such as memory, learning and attention as well as mood and motor function. Post mortem studies suggest that abnormalities of α4ß2*-nAChRs are closely linked to histopathological hallmarks of Alzheimer's disease (AD), such as amyloid aggregates/oligomers and tangle pathology and of Parkinson's disease (PD) such as Lewy body pathology and the nigrostriatal dopaminergic deficit. In this review we summarize and discuss nicotinic receptor imaging findings of 2-[18F]FA-85380 PET, [11C]nicotine PET and 5-[123I]IA-85380 SPECT studies investigating α4ß2*-nAChR binding in vivo and their relationship to mental dysfunction in the brain of patients with AD and patients out of the spectrum of Lewy body disorders such as PD and Lewy body dementia (DLB). Furthermore, recent developments of novel α4ß2*-nAChR-specific PET radioligands, such as (-)[18F]Flubatine or [18F]AZAN are summarized. We conclude that α4ß2*-nAChR-specific PET might become a biomarker for early diagnostics and drug developments in patients with AD, DLB and PD, even at early or prodromal stages.

[Superinfected epidermal inclusion cyst of the thigh with development of squamous cell carcinoma--case report of a rare complication]. / Superinfektion einer epidermalen Inklusionszyste des Oberschenkels mit Ausbildung eines Plattenepithelkarzinoms--Fallbericht einer seltenen Komplikation.

Epidermal cysts (atheroma) are the most common benign tumours of the skin with ubiquitous localisation all over the body. However, rupture of the atheroma and formation of an inclusion cyst with additional superinfections are frequently seen. Malignant transformations have rarely been reported. Presented here is the unusual case of a 65-year-old woman with multiple atheromas and a distinctive tumour of the upper limb. Imaging diagnostics showed malignant deformation. Contrary to the imaging findings the histological/microbiological examination showed an enormous superinfected and ruptured epidermoid cyst with multiple abscess formation in the ventral upper limb. Radical surgical restoration with salvage of the limb was frustrated because of honey-combed anterior soft tissue and the changing bacterial spectrum. After resection of the complete ventral compartment, remission was realised approximately. In the follow-up there was a recurring infection with spontaneous fistula formation that histologically impressed as a squamous cell carcinoma. After proximal ablation of the upper limb, total rehabilitation of the infection as well as the malignoma could be achieved.

[Secondary telangiectatic osteosarcoma of the left femur. A case presentation of an unusual course of disease]. / Sekundäres teleangiektatisches Osteosarkom des linken Femurs. Darstellung eines ungewöhnlichen Krankheitsverlaufs.

BACKGROUND: This article presents the unusual case of a 73-year-old male patient who was treated with primary interlocking nailing after a pathological femoral fracture. DIAGNOSTICS: Despite comprehensive diagnostics including several biopsies, a tumor could not be detected. In 2008 when progressive cystic femoral destruction leading to loosening of the nail necessitated a partial femoral prosthesis, an osteosarcoma could first be diagnosed in the resected bone. THERAPY: Advanced progression of the tumor required an extended hip exarticulation. During the current restaging of the now 84-year-old patient no tumor could be detected. CONCLUSION: When a malignancy cannot be excluded even by repeated biopsies of radiologically suspicious structures, an adequate tumor staging followed by close monitoring should be carried out. For a clinically silent, long-term course of cystic destruction of a long bone over several years, an age over 60 years and a lack of distant metastases, an atypical osteosarcoma should be considered in the differential diagnosis.