[Imaging of the paranasal sinuses and anterior skull base]. / Bildgebung der Nasennebenhöhlen und der Frontobasis.

Due to the complex anatomy of the anterior skull base and paranasal sinuses, radiologic diagnostics in this area are challenging. Magnetic resonance imaging (MRI) and computed tomography (CT) are the primary indicated modalities. Guidelines helping to select the appropriate modality have been published by the German Society of Head and Neck Radiology and the Society of Otorhinolaryngology. The present article presents an overview of the current radiologic procedures and their optimized implementation using clinical examples. These examples highlight the fact that a combination of at least CT and MRI is frequently required. Use of CT for intraoperative navigation is everyday practice in clinical routine. Occasionally, additional procedures such as angiography or myelography are necessary, particularly in cases of preoperative vascular diagnostics or embolization. Overall, evaluation of radiologic diagnostics in this area is complex; it requires experience and knowledge of the disease, as well as an understanding of the diagnostic procedures. Close collaboration between head and neck surgeons and radiologists is thus essential.

[Imaging for surgical planning : Tumor surgery including reconstructive procedures]. / Bildgebung zur Operationsplanung : Tumoroperationen einschließlich rekonstruktiver Verfahren.

Alongside clinical investigation, imaging is an important diagnostic modality for guiding treatment decisions and particularly for surgical planning in head and neck cancer. The significance and type of imaging depends on localization of the primary tumor. Beside the primary tumor, each imaging procedure must also include the lymph nodes, in order to develop an overall concept of surgical treatment. In addition to the superficial growth of a tumor, it is of utmost importance that its infiltration also be detected by imaging, in order to define the extent of tumor resection and identify potentially necessary reconstructive procedures. The type of imaging needed to understand tumor localization and size, e.g., CT or MRI, depends on the region. In some cases the methods are complementary.

[Diagnosis and treatment of parapharyngeal space tumors]. / Therapie parapharyngealer Tumoren.

The parapharyngeal space extends from the nasopharynx to the oropharynx. It is bordered medially by the pharyngeal wall and the constrictor pharyngis muscles, and laterally by the mandible. One distinguishes between a pre- and a poststyloid space. Tumors of the parapharyngeal space are rare and represent less than 1 % of all head and neck neoplasms. Benign (70-80 %) as well as malignant (20-30 %) tumors arise from different structures of the parapharyngeal space, mainly from salivary glands and nerve structures. Concerning salivary gland tumors, most are pleomorphic adenomas typically appearing in the prestyloid space, whereas the schwannomas that may also arise are located in the poststyloid space. The main symptom is dysphagia, with the tumor generally presenting as a visible bulking of the pharyngeal wall, in rare cases also as an externally visible cervical mass. Treatment is generally surgical resection, particularly in benign tumors, preferably via transcervical access. If R0 resection of malignancies is possible, this should be performed. In malignant lymphomas and nonresectable tumors, primary chemo-, radio-, or combination therapy should be considered after histologic confirmation. For neurogenic tumors, particularly vagal nerve schwannoma and especially in older patients, a wait-and-scan strategy is most favorable, since postoperative vagal palsy is unavoidable with surgical resection. Treatment planning for parapharyngeal space tumors requires good knowledge of topographic anatomy and careful evaluation of imaging findings.

MRI during radiotherapy of glioblastoma : Does MRI allow for prognostic stratification?

AIM: To evaluate the role of magnetic resonance imaging (MRI) as a predictor for the clinical course in patients with glioblastoma. PATIENTS AND METHODS: In 64 patients with glioblastoma undergoing (chemo)radiotherapy MRI studies were obtained before radiation, after 30 gray (Gy), after 60 Gy and during follow-up. MRI findings were assigned to categories: definite progression, questionable progression, no change. Patients were followed clinically. RESULTS: At 30 Gy, 23 of 64 patients (36 %) demonstrated definite (dp; n = 15) or questionable (qp; n = 8) progression; in 41/64 (64 %) no change was found compared with preradiation MRI. After radiotherapy at 60 Gy, 26 of 64 (41 %) patients showed dp (n = 18) or qp (n = 8). In 2 cases with qp at the 30 Gy MRI, progress was unquestionable in the 60 Gy MRI study. In the 64 patients, 5 of the 60 Gy MRIs showed dp/qp after being classified as no change at the 30 Gy MRI, 2 of the 30 Gy MRIs showed qp, while the 60 Gy MRI showed tumour regression and 3 fulfilled the criteria for pseudoprogression during ongoing radiotherapy. The 30 Gy study allowed for prognostic stratification: dp/qp compared to stable patients showed median survival of 10.5 versus 20 months. CONCLUSION: MR follow-up after 30 Gy in patients undergoing (chemo)radiotherapy for glioblastoma allows prognostic appraisal. Pseudoprogression has to be taken into account, though rare in our setting. Based on these findings, early discussion of treatment modification is possible.

The Whole Spectrum of Alcohol-Related Changes in the CNS: Practical MR and CT Imaging Guidelines for Daily Clinical Use.

UNLABELLED: Alcohol addiction is the most common drug addiction. Alcohol passes both the placenta as well as the blood-brain barrier and is in multiple ways neurotoxic. Liver diseases and other systemic alcohol-related diseases cause secondary damage to the CNS. Especially in adolescents, even a single episode of severe alcohol intoxication ("binge drinking") may result in life-threatening neurological consequences. Alcohol-related brain and spinal cord diseases derive from multiple causes including impairment of the cellular metabolism, often aggravated by hypovitaminosis, altered neurotransmission, myelination and synaptogenesis as well as alterations in gene expression. Modern radiological diagnostics, MRI in particular, can detect the resulting alterations in the CNS with a high sensitivity. Morphological aspects often strongly correlate with clinical symptoms of the patient. It is less commonly known that many diseases considered as "typically alcohol-related", such as Wernicke's encephalopathy, are to a large extent not alcohol-induced. Visible CNS alterations are thus non-pathognomonic and demand careful evaluation of differential diagnoses. This review article elucidates the pathogenesis, clinical aspects and radiological image features of the most common alcohol-related CNS diseases and their differential diagnoses. KEY POINTS: Alcohol-associated changes in the CNS are common and radiologically assessable. They are often subtle and allow multiple differential diagnoses besides alcohol consumption. Knowledge of clinical exams and lab results is crucial for diagnostic accuracy.

Bevacizumab treatment in malignant meningioma with additional radiation necrosis. An MRI diffusion and perfusion case study.

BACKGROUND AND PURPOSE: Recently two retrospective cohort studies report efficacy of bevacizumab in patients with recurrent atypical and anaplastic meningioma. Another successful therapeutic option of bevacizumab seems to be treatment of cerebral radiation necrosis. However, the antiangiogenic effects in MRI diffusion and perfusion in meningiomas have not been previously described in detail. The objective of this research was to evaluate the clinical and MR imaging effects of bevacizumab in a malignant meningioma patient harboring additional cerebral radiation necrosis. CASE PRESENTATION: We report the case of an 80-year-old woman who underwent bevacizumab therapy (5 mg/kg every 2 weeks for 2 months) for treatment of a symptomatic radiation necrosis in malignant meningiomatosis of World Health Organization (WHO) grade III. The patient was closely monitored with MRI including diffusion and perfusion studies. Upon bevacizumab therapy, the clinical situation was well stabilized over a period of 4 months until the patient unfortunately died due to pneumonia/septicemia probably unrelated to bevacizumab therapy. Consecutive MRI demonstrated 4 important aspects: (1) considerable decrease of the contrast medium (CM)-enhanced radiation necrosis, (2) mixed response with respect to the meningiomatosis with stable and predominantly growing tumor lesions, (3) a new diffusion-weighted imaging (DWI) lesion in a CM-enhanced tumor as described in gliomas, which we did not interpret as a response to bevacizumab therapy, and (4) new thrombembolic infarcts, which are a known side-effect of bevacizumab treatment. CONCLUSION: Bevacizumab is effective in the treatment of radiation necrosis. We could not confirm the potential antitumor effect of bevacizumab in this patient. However, we could describe several new radiographic effects of bevacizumab therapy in malignant meningioma.

Patient selection for mechanical thrombectomy.

PURPOSE: To evaluate the influence of tissue parameters as assessed by multimodal computed tomography and procedural parameters on clinical outcome after mechanical thrombectomy. METHODS: A total of 301 consecutive patients with acute onset ischemic stroke were included in this study. Of these, 65 had thromboembolic occlusions of the carotid T or middle cerebral artery (MCA) and underwent mechanical thrombectomy. Tissue parameters were given by unenhanced CT and perfusion CT (PCT) parameter maps of total hypoperfused tissue, infarct core, and tissue at risk. Procedural parameters comprised time from symptom onset (SO) to PCT, from SO to the first angiographic series, and from SO to vessel recanalization (occlusion time). In a subset of 22 fully recanalized occlusions, infarcted tissue and "tissue at risk" as defined by PCT were coregistered to final infarcts on follow-up imaging. RESULTS: Thrombolysis in cerebral infarction score (TICI) 2b/3 recanalization was achieved in 58/65 patients (89%). Only the infarct core size (p = 0.007) and the ratio of the infarct core relative to the tissue at risk (p = 0.001) yielded significant differences regarding the clinical outcome. Small infarct cores and low ratios of core size relative to the tissue at risk were correlated with a favorable outcome after mechanical thrombectomy. In the PCT coregistration subset, the congruency between predicted infarct cores and final infarcts was 68%, and between tissue at risk and final infarcts 7%, respectively. CONCLUSIONS: The size of the infarct core and the ratio relative to the tissue at risk are more relevant parameters for clinical outcome after mechanical thrombectomy than time related factors.

Combined radio-colour contrast in the examination of ballistic head models.

The conventional analysis of ballistic gelatine is performed by transillumination and scanning of 1-cm-thick slices. Previous research demonstrated the advantages of colour and radio contrast in gelatine for computed tomography (CT). The aim of this study was to determine whether this method could be applied to head models in order to facilitate their examination. Four head models of about 14 cm in diameter were prepared from two acryl hollow spheres and two polypropylene hollow spheres. Acryl paint was mixed with barium meal and sealed in a thin foil bag which was attached to the gelatine-filled sphere which was covered with about 3-mm-thick silicone. The head models were shot at using 9 mm × 19 expanding bullets from 4 m distance. The models were examined via multislice CT. The gelatine core was removed; the bullet track was photographed and cut into consecutive slices which were scanned optically. CT images were processed with Corel Photo-Paint. Optical and radiological images were analysed using the AxioVision software. The disruption of the gelatine within the head model was visualised by extensive distribution of paint up to the end of the finest cracks and fissures and along the whole bullet track. CT imaging with excellent radio contrast in the gelatine cracks caused by the temporary cavity allowed for multiplanar reconstruction. We conclude that the combination of colour contrast in gelatine with contrast material-enhanced CT facilitates accurate measurements in ballistic head models.

Noninvasive evaluation of cerebral arteriovenous malformations by 4D-MRA for preoperative planning and postoperative follow-up in 56 patients: comparison with DSA and intraoperative findings.

BACKGROUND AND PURPOSE: 4D-MRA is a promising technique in the diagnosis and follow-up of cAVMs. The purpose of this study was to compare 4D-MRA in the pre- and postoperative evaluation of cAVMs with DSA or intraoperative findings as the standards of reference regarding qualitative and quantitative parameters. MATERIALS AND METHODS: Fifty-six consecutive patients with cAVMs (30 women) underwent both 4D-MRA and DSA. Preoperative 4D-MRA was excluded from analysis in 1 patient (movement artifacts). Twenty-five patients underwent surgery on cAVMs and underwent both imaging modalities pre- and postoperatively. 4D-MRA was performed with either 0.5-mol/L gadolinium-diethylene-triamine pentaacetic acid (group 1: voxel size, 1.1 × 1.1 × 1.4 mm(3); 608 ms/dynamic frame; 19 patients) or 1.0-mol/L gadobutrol (group 2: voxel size, 1.1 × 1.1 × 1.1 mm(3); 572 ms/dynamic frame; additional alternating view sharing; 37 patients). Two readers independently reviewed 4D-MRA and DSA regarding the Spetzler-Martin classification, arterial feeders, and postoperative residual filling. Vessel sharpness, vessel diameter, and VBC of 4D-MRA were quantified. RESULTS: Preoperative Spetzler-Martin classification 4D-MRA and DSA ratings matched in 55/55 patients (Spetzler-Martin grades: I, 12; II, 22; III, 15; IV, 5; V, 1), and 93/100 arterial feeders were correctly identified by preoperative 4D-MRA (7 additional arterial feeders identified by DSA only: group 1, 3/19; group 2, 4/36). Postoperative 4D-MRA and DSA matched in 25/25 patients (residual filling, 1/25). Vessel sharpness and diameters did not differ substantially between the 2 groups. VBC was significantly higher in group 2 (P < .005). CONCLUSIONS: 4D-MRA is a reliable tool that allows predicting Spetzler-Martin classification and postoperative residual filling; it hence allows substituting DSA in the pre- and postoperative evaluation of patients with cerebral AVMs.

Mechanical thrombectomy compared to local-intraarterial thrombolysis in carotid T and middle cerebral artery occlusions: a single center experience.

PURPOSE: The aim of the study was to examine the effects of mechanical thrombectomy using the Solitaire stent in patients with thromboembolic occlusions of the intracranial carotid artery bifurcation (carotid T) or middle cerebral artery (MCA) and to compare the results with a historical cohort treated with local intraarterial thrombolysis using urokinase. METHODS: The time intervals from stroke onset to treatment, recanalization rates, occlusion sites, recanalization times and functional outcomes on the modified Rankin scale at 3 months in 25 patients treated with the Solitaire stent between 2010 and 2011 were evaluated. The data were compared with those of a historical cohort of 62 patients treated with local intraarterial thrombolysis between 1992 and 2001. RESULTS: A total of 15 out of 25 (60%) patients treated with mechanical thrombectomy and 25 out of 62 (40%) treated with local intraarterial thrombolysis achieved a modified Rankin score of ≤2 (p = 0.07). Occlusion sites, intervals from stroke onset to treatment and rates of parenchymal hematomas, 3 out of 25 (12%) versus 8 out of 62 (13%), were similar in both cohorts while the recanalization rate was significantly higher, 22 out of 25 (88%) versus 33 of 62 (53%), in the mechanical thrombectomy group (p ≤ 0.01). CONCLUSION: The data show that mechanical thrombectomy is superior to local intraarterial thrombolysis with respect to the recanalization rate in patients with thrombeoembolic carotid T or MCA occlusions.

Gated multidetector computed tomography. A technique to reduce intracranial aneurysm clip and coil artifacts.

BACKGROUND AND PURPOSE: Streak artifacts caused by aneurysm clips and coils impede image quality in multidetector computed tomography (MDCT). The authors propose a technique to minimize these artifacts by gated data reconstruction and shifting the reconstruction window. PATIENTS AND METHODS: Intracranial CT angiograms were acquired in the follow-up of six patients with clipped and coiled intracranial aneurysms, respectively. Images were reconstructed from four consecutive 45 degrees rotated segments with an acquisition time of 52.5 ms/segment. Data acquisition was gated via an external pacemaker cable-connected to the scanner. RESULTS: Artifact orientation could be rotated by shifting the reconstruction window and interesting vessel segments visualized without disturbing streak artifacts. This allowed to assess the posterior communicating artery origin in two cases and a middle cerebral artery aneurysm remnant in another case, respectively. However, due to a higher noise interesting vessel segments were not adjustable in another three patients. CONCLUSION: Gated MDCT is a promising technique to reduce the amount and to change the position of artifacts induced by clips or coils.

[Molecular imaging of apoptosis in cardiovascular diseases]. / Molekulare Bildgebung der Apoptose bei kardiovaskulären Erkrankungen.

Molecular imaging of functional parameters such as apoptosis (programmed cell death) in vivo opens new possibilities in clinical diagnostic and scientific research. Especially in the case of cardiovascular diseases that are mainly responsible for both morbidity and mortality in Western industrial nations, innovative non-invasive examination strategies are necessary for early diagnosis of these diseases. Since apoptosis unlike necrosis is present even after minor alterations of the microenvironment of cells and has been shown to be involved in a large number of cardiovascular diseases, there are currently several experimental studies underway with the goal of imaging apoptosis in vivo. The review discusses the basics of apoptosis in myocardial infarction, myocarditis, atherosclerosis, restenosis after angioplasty and stent implantation, currently used imaging techniques, achieved results, and future possibilities for molecular imaging of apoptosis.

Lung transplantation in the Fischer 344-->Wistar Kyoto rat strain combination is not suitable to study bronchiolitis obliterans.

BACKGROUND: To elucidate the pathogenesis of bronchiolitis obliterans (BO) a reliable animal model is needed. According to the literature, lung transplantation from Fischer 344 (F344) to Wistar Kyoto (WKY) rats is the only model that reliably results in BO without a further stimulus. METHODS: We performed orthotopic left lung transplantation in F344 to WKY rats and in both isogeneic rat strain combinations. Suture and cuff techniques for anastomosis were compared. The time course of rejection and the morphology of the bronchial anastomoses were documented by repeated flat-panel volumetric computed tomography (fpVCT) in the living animal. Graft histopathology was analyzed 3 months post-transplant. RESULTS: According to the graft outcome, as revealed by fpVCT, grafts were sub-divided into two groups: In Group 1, infiltrates due to acute rejection occurred early after transplantation and resolved thereafter. Graft histopathology showed minor changes but no BO. In Group 2, acute rejection caused total atelectasis that never resolved. After 3 months, grafts were shrunken and exhibited tissue remodeling with some similarities to BO. No correlation between graft outcome and anastomotic technique was apparent. CONCLUSIONS: Modeling lung transplantation using the F344-to-WKY combination is without clinical relevance because BO does not develop in grafts with life-sustaining function. Consecutive fpVCT is useful to monitor pathologic changes in rat pulmonary grafts.

Extensive abdominal splenosis: imaging features.

We present the case of a 22-year-old patient who had splenectomy in childhood after trauma and had a known chronic active infection with hepatitis C. Imaging procedures in different radiologic modalities diagnosed diffuse intraabdominal splenosis. Splenosis is a rare, severe complication of splenic trauma or surgery, but the pathogenesis is not clear. Imaging features play a key role in the diagnosis of ectopic splenic tissue, which must be differentiated from malignancies, especially from lymphoma. Splenosis itself may induce relapse of hematologic diseases, mainly autoimmune thrombocytopenia.