Rainer Linke

Carcinoma of unknown primary in the head and neck: Comparison between positron emission tomography (PET) and PET/CT

Comparison of the diagnostic validity of positron emission tomography (PET) alone with integrated PET and CT (PET/CT) in the search for occult primary tumors in patients with cancer of unknown primary (CUP) site in the head and neck.

Endogenous GLP-1 Regulates Postprandial Glycemia in Humans: Relative Contributions of Insulin, Glucagon, and Gastric Emptying

OBJECTIVE Synthetic glucagon-like peptide-1 (7-36)amide (GLP-1) lowers postprandial (pp) glycemia by stimulating insulin and inhibiting glucagon release and delaying gastric emptying (GE). However, the biological effects of the endogenous peptide and their relative contributions to pp glycemia remain to be defined in detail. Using the specific GLP-1 receptor antagonist exendin(9-39)amide [Ex(9-39)], we studied the exact impact of GLP-1 after an oral meal in humans. RESEARCH DESIGN AND METHODS After a 50-min basal period, 12 healthy subjects ingested a 412-kcal mixed semisolid meal containing 30 g oatmeal, labeled with 99mTc-Sn-colloid. GE was measured by high-resolution scintigraphy until 210 min after meal ingestion. In random order, saline or Ex(9-39) at 900 pmol/kg·min was infused iv. Additionally, in six subjects gastric motility was measured by antroduodenal manometry and a gastric barostat in parallel. RESULTS Ex(9-39) increased pp blood glucose excursions during the first 60 min after the meal (43.9 ± 5.4 vs. 35.9 ± 3.6 mg/dl, P = 0.008; pp peak glucose 154.0 ± 5.5 vs.141.0 ± 4.7 mg/dl, P = 0.009). Insulin increased slightly with Ex(9-39), whereas the insulin to glucose ratio was unchanged. pp glucagon was significantly increased with Ex(9-39) (7.5 ± 2.4 vs. 3.2 ± 2.1 pg/ml, P = 0.024). GE and accordingly gastric motility did not change with Ex(9-39). Multiple linear regression analysis revealed only changes of pp glucagon to be significantly associated with increased pp glycemia under Ex(9-39) (R = 0.678, P = 0.015). CONCLUSIONS Released after an oral meal, GLP-1 lowers pp glycemia. In this study, the inhibition of glucagon release was a major determinant of the acute GLP-1 action in healthy subjects. In contrast, gastric emptying was not changed by GLP-1 receptor antagonism.

Regional lymph node involvement in T1 papillary thyroid carcinoma: a bicentric prospective SPECT/CT study

PurposeHybrid imaging combining single photon emission computed tomography (SPECT) with 131I and X-ray computed tomography (CT) performed at radioablation (RA) for thyroid carcinoma more accurately detects regional lymph node metastases (LNM) than does planar imaging. In this bicentric prospective study we used hybrid imaging in conjunction with histopathological examination to measure LNM frequency in a consecutive group of patients referred for RA due to stage T1 papillary thyroid carcinoma (PTC).MethodsAt the Departments of Nuclear Medicine of the Ludwig Maximilian University of Munich and the Friedrich Alexander University of Erlangen-Nuremberg SPECT/spiral CT is routinely performed in all PTC subjects at the time of RA. Screening of our SPECT/CT databases for PTC patients with T1 histology produced 98 patients from Munich and 53 patients from Erlangen, including 96 of 151 patients with microcarcinoma. In 69 patients of the entire group, cervical lymph node dissection had been performed, whereas nodal staging in the remaining 82 subjects was based on SPECT/CT.ResultsLNM incidence in the whole group was 26% [95% confidence interval (CI): 20–33%] versus 22% (95% CI: 15–31%) in the microcarcinoma subgroup. SPECT/CT was more accurate in 24.5% of our patients than planar imaging with regard to nodal staging.ConclusionLNM occurs in one quarter of all patients with T1 PTC, and also in the subset with microcarcinoma. Performing 131I SPECT/CT, either with therapeutic or diagnostic radioactivities, directly after thyroidectomy should provide more accurate staging of T1 PTC, thus facilitating optimal therapeutic management.

Feasibility, Toxicity, and Efficacy of Short Induction Chemotherapy of Docetaxel Plus Cisplatin or Carboplatin (TP) Followed by Concurrent Chemoradio ­ therapy for Organ Preservation in Advanced Cancer of the Hypopharynx, Larynx, and Base of Tongue

AbstractPurpose:Concurrent chemoradiotherapy (CRT) is standard treatment for advanced head and neck cancer. Whether short induction chemotherapy (ICT) provides additional benefit or, in particular, predictive benefit for the response to chemoradiotherapy is an open question. The present study aimed to assess the feasibility, toxicity, and efficacy of induction with docetaxel and platinum salt (TP) and subsequent CRT.Patients and Methods:A total of 25 patients with functionally inoperable cancer of the base of the tongue, hypopharynx, or larynx received 1 cycle of docetaxel (75 mg/m², day 1) combined with either cisplatin (30 mg/m², days 1–3; n = 23) or carboplatin (AUC 1.5 days 1–3; n = 2). Responders (n = 22, >30% tumor reduction, graded by endoscopy) and 1 non-responder received CRT (target dose: 69–72 Gy) with cisplatin/paclitaxel, carboplatin/paclitaxel, or cisplatin/docetaxel.Results:All patients completed ICT with acceptable toxicity (leukocytopenia grade 4: 8%). The remission rate of the primary tumor was 88% (22/25 patients). There was no need to delay CRT due to toxicity in any case. Each patient received the full radiation dose. Of the patients, 56% received >80% of the chemotherapy. The acute toxicity of CRT was moderate, no grade 4 toxicities occurred, while grade 3 toxicities included the following: infection (39%), dermatitis (13%), leukocytopenia (30%), and thrombocytopenia (4%). The local control rate was 84.6% ± 8.5% and the survival rate was 89.6% ± 7.2% at 12 months. Organ preservation was possible in 22/23 (95%) cases.Conclusion:Short induction with a TP regimen and subsequent CRT with a taxan is feasible and associated with an encouraging local control rate.ZusammenfassungZiel:Die simultane Radiochemotherapie (CRT) ist Standard bei fortgeschrittenen Kopf-Hals-Tumoren. Offen ist der Stellenwert einer Kurzzeitinduktionschemotherapie (ICT), insbesondere deren prädiktive Bedeutung für das Ansprechen der Radiochemotherapie. In der Studie werden Durchführbarkeit, Toxizität und Effektivität einer Induktionschemotherapie mit Docetaxel und einem Platinsalz einschließlich der folgenden RCT berichtet.Patienten und Methode:25 Patienten mit einem nicht funktionserhaltend operablen Zungengrund-, Hypopharynx- und Larynxkarzinom erhielten einen Zyklus Docetaxel (75 mg/m2, d1) und Cisplatin (30 mg/m2 d-1–3) (n = 23) oder Carboplatin (AUC 1,5 d1-3) (n = 2). Responder (n = 22, mehr als 30% Rückbildung endoskopisch) und ein Non-Responder erhielten nachfolgend eine RCT (Zieldosis: 69–72 Gy) mit Cisplatin/Paclitaxel rsp. Carboplatin/Paclitaxel oder Cisplatin/Docetaxel.Ergebnisse:Die Induktionstherapie konnte bei allen Patienten mit akzeptabler Toxizität (Leukozytopenie Grad 4: 8%) durchgeführt werden. Die Remissionsrate des Primärtumors betrug 88% (22/25 Pat). Die Radiochemotherapie wurde in keinem Fall toxizitätsbedingt verzögert. Die Radiotherapiedosis wurde vollständig gegeben. 56% der Patienten erhielten >80% der geplanten Chemotherapie. Die Akuttoxizität der RCT war moderat, keine Grad-4-Toxizität; Grad-3-Toxizitäten: Infektion (39%), Dermatitis (13%), Leukozytopenie (30%), Thrombozytopenie (4%). Nach 12 Monaten lag die Lokalkontrolle bei 84,6% ± 8,5%, das Gesamtüberleben 89,6% ± 7,2%. Die Organerhaltquote lag bei 95% (22/23).Schlussfolgerung:Die Kurzinduktion mit TP und die nachfolgende CRT mit einem Taxan sind durchführbar und führten zu einer ermutigenden Tumorkontrolle.

Use of 18F-FDG-PET in the diagnosis of endoprosthetic loosening of knee and hip implants.

IntroductionTo diagnose septic and aseptic loosening 18-fluorodeoxyglucose positron emission tomography (18F-FDG-PET) has been described with good results for hip arthroplasties. The purpose of the present study was to examine whether there is a difference of feasibility in detecting loosening of hip versus knee prostheses by use of 18F-FDG-PET.PatientsThirty-two patients with lower limb arthroplasty complaints (74 components) were studied preoperatively with 18F-FDG-PET. The interpretation of 18F-FDG-PET was done according to evaluated criteria. The final diagnosis based on intraoperative findings in all cases including microbiological examinations.ResultsFor hip arthroplasty sensitivity/specificity of 18F-FDG-PET towards implant loosening was 80%/87%. For infectious loosening of hip endoprostheses sensitivity/specificity was 67%/83%. In knee endoprostheses sensitivity/specificity for loosening was 56%/82% and 14%/89% for infection. The sensitivity of the results for knee and hip joints in regard to infectious versus aseptic loosening was significantly different.ConclusionWe confirm that 18F-FDG-PET is an appropriate tool to diagnose hip arthroplasty loosening. Differing from that 18F-FDG-PET showed a significant lower sensitivity/specificity in detecting septic loosening of knee endoprostheses. It may therefore be necessary to use different methods to diagnose loosening of endoprostheses depending on the type of implant which is examined.

Quantification of Thyroid Volume Using 3-D Ultrasound Imaging

Ultrasound (US) is among the most popular diagnostic techniques today. It is non-invasive, fast, comparably cheap, and does not require ionizing radiation. US is commonly used to examine the size, and structure of the thyroid gland. In clinical routine, thyroid imaging is usually performed by means of 2-D US. Conventional approaches for measuring the volume of the thyroid gland or its nodules may therefore be inaccurate due to the lack of 3-D information. This work reports a semi-automatic segmentation approach for the classification, and analysis of the thyroid gland based on 3-D US data. The images are scanned in 3-D, pre-processed, and segmented. Several pre-processing methods, and an extension of a commonly used geodesic active contour level set formulation are discussed in detail. The results obtained by this approach are compared to manual interactive segmentations by a medical expert in five representative patients. Our work proposes a novel framework for the volumetric quantification of thyroid gland lobes, which may also be expanded to other parenchymatous organs.

18Fluoroethyl‐l‐tyrosine‐PET in long‐term epilepsy associated glioneuronal tumors

Purpose:  Long‐term epilepsy associated tumors (LEATs) are a frequent cause of drug‐resistant partial epilepsy. A reliable tumor diagnosis has an important impact on therapeutic strategies and prognosis in patients with epilepsy, but often is difficult by magnetic resonance imaging (MRI) only. Herein we analyzed a large LEAT cohort investigated by 18fluoroethyl‐l‐tyrosine–positron emission tomography (FET‐PET).

Skeletal SPECT/CT of the peripheral extremities -interdisciplinary approach in orthopaedic disorders-first clinical results

Bone scintigraphy, although quite sensitive to detect skeletal lesions, has a comparatively low specificity. Hybrid-cameras combining single-photon emission computed tomography (SPECT) and spiral-CT offer the opportunity to correlate scintigraphic information with high-quality visualization of morphology in one session. This may lead to an improvement in diagnostic accuracy and anatomic lesion localization. We present 11 patients, who underwent SPECT/CT of the feet (n=10) and hands (n = 1). The examinations were performed due to pain in foot or hand with the following suspected clinical diagnoses: arthrosis (n=1); fracture (n=3); osteomyelitis (n=4); reflex dystrophia (n=1); and, pain of unclear origin (n=2). All patients underwent SPECT/CT hybrid imaging using a dual-headed SPECT camera integrated with a 2-slice spiral CT scanner in one gantry. SPECT, CT, and SPECT/CT were evaluated independently from each other with respect to main diagnosis, anatomic lesion localization, and detection of a possible additional diagnosis. SPECT/CT improved lesion localization in 8 of 11 patients (73%) in comparison to SPECT alone, and in 4 of 11 patients (36%) in comparison to CT alone. Diagnostic accuracy was improved in 4 of 11 patients (36%) in comparison to either SPECT or CT alone. In conclusion, skeletal SPECT/CT improves diagnostic accuracy and lesion localization of orthopedic disorders in the feet and hands. The obtained results encouraged extensive studies to further investigate the potential gain in diagnostic accuracy brought about by SPECT/spiral-CT hybrid imaging in orthopedic disorders of the peripheral extremities.