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C Pfannenberg

Publications and source records attributed to C Pfannenberg.

12 recordsLinked to original sources
PubMed2006

[Evaluation of different breathing and contrast-protocols concerning quality and alignment in 18F-FDG PET/CT].

PURPOSE: The purpose of this study was to establish a reliable and simple parameter for alignment evaluation and the evaluation and optimization of state-of-the-art contrast-enhanced examination protocols for (18)F FDG-PET/CT. MATERIALS AND METHODS: 44 consecutive patients were referred to 4 examination protocols. Group A and B underwent single-phase, contrast-enhanced CT (90 s delay) performed either during free shallow breathing (FA; group A) or normal expiration (NormExp; group B). Groups C and D underwent arterial and portal venous multiphase examinations performed during FA (group C) or during NormExp (group D) followed by a low-dose CT scan for attenuation correction. Organ displacement in the cranio-caudal direction was correlated with a 3D-vectorial shift. For alignment evaluation discrepancies with respect to size and liver location, the spleen and kidneys were calculated. Additionally, the groups were compared with regard to the presence of CT artifacts. RESULTS: Cranio-caudal organ shift and 3D-vectorial shift showed a high correlation (r > 0.8). Single-phase CT scans performed during NormExp yielded better image quality (p < 0.001) and alignment (p < 0.01 for liver, spleen and right kidney) than those performed during FA. Differences in organ size did not differ during FA and NormExp. Depending on the evaluated organ, breathing and contrast protocol misalignment was in the cranio-caudal direction 0-27 mm (mean: 6.8; standard deviation: +/- 4.9) in multiphase CT compared to 0 - 11 mm (mean: 4.5 +/- 2.3) in single-phase examinations. CONCLUSION: 1. Organ shift in the cranio-caudal direction is a good and simple parameter for alignment evaluation. 2. Alignment and CT quality are best in expiration protocols. 3. Despite comparatively low alignment quality, integrated multiphase CT examinations show acceptable quality and alignment.

Aged↗
PubMed2005

Invasive pulmonary aspergillosis: frequency and meaning of the "hypodense sign" on unenhanced CT.

The purpose of this study was to establish the diagnostic value of central hypointensity ("hypodense sign") in lung consolidations or nodules, in severely immunocompromised or neutropenic patients, suspected of having invasive pulmonary aspergillosis (IPA), and to assess its recognition on unenhanced CT scans. Serial CT scans of the lung were retrospectively reviewed in 43 consecutive immunosuppressed patients with IPA, and assessed for the presence of the hypodense sign using standard mediastinal and lung windowing settings, as well as a special, narrower window setting (width 110-140 HU; level 15-40 HU). The temporal relationship between the occurrence of the first CT-finding suspicious of IPA and the appearance of the hypodense sign, as well as between this and the occurrence of the crescent sign, cavitation or reduction in lesion size, was evaluated. Additionally, CT-scans from 89 immunocompromised patients with viral (n=45) or bacterial (n=44) pneumonia, investigated in the same time period at our institution were reviewed, with respect to the presence of the "hypodense" sign. Unenhanced CT scans revealed the hypodense sign in 11 neutropenic patients and 2 severely immunocompromised patients, out of a total of 43 patients with IPA evaluated in this study (30.2%). The mean time between the appearance of the first CT-findings of IPA (large nodule or consolidation +/- positive halo sign) and the hypodense sign was 7.8 days, while the time interval between the hypodense sign and the occurrence of crescent sign, cavitation, or decrease of the lesion's size was 8.3 days. The hypodense sign did not occur in any of the patients with viral or bacterial pneumonia, in the control series. We consider the hypodense sign to be a supplementary tool in the diagnosis of IPA. Its sensitivity was low in our series, but the high specificity makes it valuable in predicting IPA, anticipating the occurrence of cavitation or crescent sign, which are considered specific, but late findings of IPA. The hypodense sign is recognizable also on unenhanced CT, when a narrower lung window setting is used.

Adolescent↗
PubMed2001

MR cholangiography in the diagnosis of sclerosing cholangitis in Langerhans' cell histiocytosis.

Langerhans' cell histiocytosis (LCH) is a disorder of histiocytic proliferation that primarily affects infants. Imaging findings of a rare case of lung and liver involvement in an adult are presented. High-resolution computed tomography (HRCT) of the lungs showed confluent thin-walled cystic air spaces compatible with advanced LCH. Liver CT and MRI revealed unspecific signs of fatty infiltration. Irregular widening of peripheral bile ducts was displayed in breath-hold MR cholangiography. This pattern is considered characteristic for sclerosing cholangitis and should support the diagnosis of LCH in case of concomitant cystic pulmonary disease, even in adult patients.

Aged↗
PubMed1998

Orbital reconstruction with individually copy-milled ceramic implants.

Diagnostic advances such as computed tomography and new surgical techniques have dramatically improved both the functional and aesthetic outcome of orbital reconstructions. Taking a further approach, we designed ceramic implants (Bioverit) on the basis of stereolithographic models. After copy milling a resin template with a commercially available dental unit (Celay), the prefabricated implants were inserted for reconstruction of the lamina papyracea (n = 1), zygomatic complex (n = 2), infraorbital floor (n = 5), and rim (n = 3). Intraoperatively, only slight modifications of the implants had to be performed. The results were encouraging, as all cases showed a good aesthetic and functional postoperative outcome. Preoperative evaluation of the osseous defect and prefabrication of the required implant reduced operating time and patient morbidity significantly.

Adult↗
PubMed1996

Multifocal extra-abdominal desmoid tumor--diagnostic and therapeutic problems.

The case of an 18-year-old girl is described who 1 year after surgical stabilisation of a spine injury developed a multifocal desmoid tumor in the scar region and another at a distance away from the scar in the area of the left scapula. After nononcological resection of both tumors subsequent diagnosis with magnetic resonance imagins (MRI) showed a questionable recurrence only in the scar; positron emission tomography failed to elucidate the local situation. Because a radical re-resection would mean mutilation, and local radiation may damage the spinal cord, a 'wait-and-see' strategy was chosen for further follow-up.

Adolescent↗
PubMed1990

[Agenesis of the inferior vena cava].

It is reported on an asymptomatic rare vascular anomaly, the agenesis of the inferior vena cava. The knowledge of such malformations is important in operative procedures.

Adult↗
PubMed1989

[The use of imaging procedures following kidney transplantation--diagnostic strategy].

Despite the continuously increasing number of successfully transplanted kidneys, graft and patient are still "threatened" by several postoperative complications as acute and chronic rejection, acute tubular necrosis, urologic and vascular complications and disorders caused by immunosuppressive medication. An early and safe detection of these conditions is of high clinical importance and a challenge to diagnostic imaging. All radiologic methods and nuclear medicine have their value for transplantation diagnostics, but in recent years a trend to noninvasive methods with no contrast media and little discomfort to the patient is clearly visible (sonography, magnetic resonance). Rational diagnostic strategies for various conditions after renal transplantation are described.

Diagnostic Imaging↗
PubMed1989

[Diagnostic strategy in urolithiasis].

The roentgenological diagnostics of urolithiasis must be carried out with regard to the therapeutic consequences. With the appropriate use of new imaging methods the prevailing techniques are native radiographs and sonography for proof or rejection of suspected renal calculus. Excretion urography is no longer justified as the primary method of investigation. Already practically proven diagnostic schedules are described. Interdisciplinary cooperation of radiologist and urologist is essential for the introduction of diagnostic strategies into practice.

Humans↗