133Xe-DSPECT: Normalwerte von zerebraler Ruhedurchblutung und Reservekapazität

Using the 133Xe-DSPECT technique, quantitative measurements of regional cerebral blood flow (rCBF) were performed before and after provocation with acetazolamide (Diamox) i. v. in 32 patients without evidence of brain disease (normals). In 6 cases, additional studies were carried out to establish the time of maximal rCBF increase which was found to be approximately 15 min p. i. 1 g of Diamox increases the rCBF from 58 ±8 at rest to 73±5 ml/100 g/min. A Diamox dose of 2 g (9 cases) causes no further rCBF increase. After plotting the rCBF before provocation (rCBFR) and the Diamox-induced rCBF increase (reserve capacity, Δ rCBF) the regression line was Δ rCBF = −0,6 x rCBFR +50 (correlation coefficient: r = −0,77). In normals with relatively low rCBF values at rest, Diamox increases the reserve capacity much more than in normals with high rCBF values before provocation. It can be expected that this concept of measuring rCBF at rest and the reserve capacity will increase the sensitivity of distinguishing patients with reversible cerebrovascular disease (even bilateral) from normals.

Die Leberperfusions-Szintigraphie: Methodik, Normalwerte und Ergebnisse der Verlaufsbeobachtung von Patienten mit Ösophagusvarizen

Bei 26 Patienten wurde der hepatische Perfusionsindex (HPI) durch einen Vergleich von arteriellem und portalvenösem Anstieg der Zeitaktivitätskurven über der Leber bestimmt. 10 Patienten ohne Anhalt für eine hepatobiliäre Erkrankung (Gruppe A) dienten als Normalkollektiv. Bei 16 Patienten lag eine Leberzirrhose mit Ösophagusvarizen Grad III bis IV vor. Die HPI-Bestimmung erfolgte zweimal im Abstand von 6 Monaten. Bei Gruppe A war HPI mit durchschnittlich 56% signifikant (p <0,001) höher als bei den Patienten mit Leberzirrhose und Ösophagusvarizen (18%). Bei guter »Intra- und Interobserver «-Übereinstimmung (r = 0,96 bzw. 0,92) ist es einer großen intraindividuellen Streuung der Leberdurchblutung zuzuschreiben, daß sich geringe HPI-Änderungen nicht messen lassen. Eine Unterscheidung zwischen normaler portalvenöser Leberdurchblutung und mittel- bis hochgradiger Reduktion ist durch dieses Verfahren sicher möglich.

Erste Ergebnisse der Radioiodtherapie bei multifokaler und disseminierter Autonomie der Schilddrüse unter Verwendung eines TcTUs-adaptierten Dosiskonzepts

Ziel: Die Studie untersucht prospektiv die Wirksamkeit eines an den prätherapeutischen 99mTc-Pertechnetat Uptake der Schilddrüse unter Suppression (TcTUs) angepaßten Dosiskonzeptes zur Radioiodtherapie (RIT) bei Patienten mit multifokaler (MFA) und disseminierter Autonomie (DISA). Dieses Konzept berücksichtigt die gesamte Schilddrüse als Zielvolumen und verwendet Herddosen von 150 Gy bis 300 Gy entsprechend dem TcTUs als Maß für das »autonome Volumen« der Schilddrüse. Methoden: Es wurden 75 Patienten (54 Frauen, 21 Männer; Alter 71 ± 9 Jahre) mit MFA oder DISA ausgewertet. Die Therapie wurde bei Normalwerten für fT3 und fT4 und bei endogener Suppression des TSH durchgeführt. Als Herddosen wurden appliziert: bei einem TcTUs zwischen 1,5-2,5% 150 Gy, bei 2,51-3,5% 200 Gy, bei 3,51-4,5% 250 Gy und bei >4,5% 300 Gy. Die Abschätzung der zu applizierenden Aktivität erfolgte mit einer modifizierten Marinelli-Formel. Als Therapieerfolg galt ein TSH >0,5 mU/l und ein Verschwinden der autonomen Areale im Szintigramm bzw. ein posttherapeutischer TcTU <1,5%. Die mittlere Nachbeobachtungszeit betrug 8 ± 4 Monate. Ergebnisse: Die Erfolgsraten betragen im Durchschnitt 92%. Nur in einem Fall kam es zu einer konsekutiven subklinischen Hypothyreose und in einem weiteren Fall trat eine immunogene Hyperthyreose auf. Schlußfolgerung: Die vorliegenden Daten sprechen dafür, daß auch Patienten mit ausgeprägter Autonomie (TcTUs >3,5%) bei einzeitiger Therapie mit einer Erfolgsrate von über 90% mit dem hier vorgestellten Dosiskonzept behandelt werden können. Die Frühhypothyreoserate ist insgesamt sehr niedrig.

Klinische Wertigkeit der Positronen-Emissions-Tomographie (PET) bei onkologischen Fragestellungen: Ergebnisse einer interdisziplinären Konsensuskonferenz

Ziel: Es ist das Ziel der vorliegenden Arbeit, an Hand bisher publizierter Studienergebnisse eine Beurteilung des klinischen Stellenwertes von PET in der Onkologie zu erarbeiten. Methoden: Im Rahmen einer interdisziplinären Konferenz mit namhaften Experten wurde eine Wertung des gegenwärtigen Stands von PET in der Onkologie an Hand der in der Literatur dokumentierten Studienergebnisse erarbeitet. Angestrebt wurde eine differenzierte Bewertung von PET für die klinische Anwendung in fünf Klassen (1a, 1b, 2a, 2b, 3) von »angemessen« (1a), »akzeptabel« (1b), »hilfreich« (2a), »noch keine Bewertung möglich« (2b), »ohne Nutzen« (3). Ergebnisse: Für den klinischen Einsatz in der Onkologie ist 2-F18-Fluorodeoxyglukose (FDG) das Radiopharmakon der Wahl. PET ist klinisch in der Patientenversorgung zur Rezidivdiagnostik von high-grade Gliomen (FDG), low-grade Gliomen (C-11 Methionin oder F-18 Tyrosin), für die Dignitätsdiagnostik des peripheren Lungenrundherdes bei Risikopatienten sowie für die Diagnostik des Pankreaskarzioms indiziert (Indikation 1a). PET kann in der Patientenversorgung bei folgenden Indikationen (1b) eingesetzt werden: »low-grade« Gliome, Suche nach unbekanntem Primärtumor bei Kopf-Hals-Tumoren, Rezidivdiagnostik des nicht kleinzelligen Bronchialkarzinoms sowie des Rektumkarzinoms, Lymphknotenstaging beim nicht kleinzelligen Bronchial-Karzinom, Pan-kreas-Karzinom, muskelinvasiven Blasen-Karzinom und Hoden-Karzinom. Staging bei M. Hodgkin (Stad. I/II versus III), frühe Therapiekontrolle bei Resttumor und Rezidivdiagnostik bei M. Hodgkin und hochmalignen Non-Hodgkin-Lymphomen, Lymphknoten-Staging und Fern-metastasensuche beim malignen Melanom (Breslow >1,5 mm), Lymphknoten- und Fernmetastasen-Nachweis beim Schilddrüsen-Karzinommit erhöhtem hTg und nicht radiojodspeichernden Metastasen. Zahlreiche weitere Indikationen zeichnen sich bereits jetzt ab, sind jedoch noch weniger gut durch wissenschaftliche Studien belegt. Für die meisten Indikationen außerhalb wissenschaftlicher Studien ist eine individuelle Kosten-Nutzen-Betrachtung durch den verantwortlichen Arzt geboten. Schlußfolgerungen: Die metabolische Bildgebung von PET besitzt für eine Vielzahl onkologischer Fragestellungen prinzipielle Vorteile gegenüber der anatomisch-morphologisch orientierten Schnittbilddiagnostik. Für die klinische Indikationsstellung ist allerdings eine differenzierte Betrachtung der spezifischen Leistungsfähigkeit von PET geboten.

Photopenic Lesions in Bone Marrow Scintigraphy Using Technetium-99m Labeled Antigranulocyte Antibody without Known Tumour

Aim: The purpose of this study was to elucidate the frequency of photopenic lesions in patients without known tumour disease by using bone marrow scintigraphy with Tc-99m labeled anti-NCA-95. Methods: Whole body immunoscintigraphy (IS) was performed in 141 consecutive patients with fever of unknown origin. The age ranged between 20 and 88 years with a mean age of 57 years. None of the patients had known tumour disease. Scans were evaluated with respect to photopenic lesions and to bone marrow distribution. Results: IS showed bone marrow defects in the axial skeleton in 16 patients (11 %). With the help of the typical scintigraphic defect pattern, the cause of the lesions was clearly identified as degenerative changes in four patients and in one patient as due to prior sternotomy. In the remaining 11 patients the origin of the defects became evident when the case history or additional imaging was consulted. The mean age of these 16 patients was 69 years ranging from 50 to 88 years. There was an age-related frequency of defects. 10% of the patients from 50 to 59 years showed defects, 60-69 years 9%, 70-79 years 30%, and 33% of the patients from 80 to 89 years had defects. IS was not hampered by tracer uptake to liver or spleen in 93 patients. Left caudal ribs were obscured in 48 patients with intense tracer uptake to the spleen. No or markedly reduced tracer uptake was found in caput humeri and caput femori in 94 and 82 patients, respectively. Patchy tracer uptake to the bone marrow of the limbs was seen in 13/62 patients showing marrow expansion in the lower limbs and 14/55 with marrow expansion in the upper limbs. The patchy pattern was asymmetric in 12 of these patients. Conclusion: The results of the present study reveal that using Tc-99m NCA-95, photopenic lesions of the bone marrow are rarely seen in patients without known malignant disease. The occurrence of benign lesions is age-related. The benign cause of the lesion was obvious from location and pattern of the lesion in about 30% of the cases. Evaluation of lesions in the upper and lower limbs may be hindered due to physiological variation of marrow distribution. Nevertheless, IS appears to be well-suited for the detection and localization of bone marrow metastases.

Imaging of a Metastatic Gastrointestinal Carcinoid by F-18-DOPA Positron Emission Tomography

The localization of carcinoids in the gastrointestinal tract is frequently difficult if not impossible with the imaging procedures used to date. It is reported on a patient with metastasizing carcinoid in whom various imaging procedures were not successful in detecting the primary tumor. Due to the importance of primary tumor proof for potential curative surgical therapy, a whole-body positron emission tomography with F-18-DOPA was performed. PET enabled localization of a potential primary tumor in the ileum. Moreover, in addition to the known abdominal lymph node and liver metastases, it detected a mediastinal lymph node metastasis and a pulmonary metastasis. F-18-DOPA whole-body PET may be a very promising imaging approach to the localization and staging of gastrointestinal carcinoids.

Precise Localization of Dysfunctional Areas in Vertebrobasilar Infarction by FDGand 0-15-H20-PET Using Standardized Image Analysis and Image Registration to 3-D MR

The advantages of standardized multimodal image analysis are demonstrated in a case of symptomatic tremor after basilar thrombosis. Functionally and structurally lesioned areas were mapped in Talairach space using 3-D MRI, cerebral FDG-PET and 0-15-H20-PET. Structural lesions were found in the left midbrain, thalamus, putamen and cerebellar areas. Voxel-based statistics in comparison to a normal data base revealed hypometabolism in the left thalamus, left red nucleus, left cerebellar hemisphere including dentate nucleus and in the left inferior olivary nucleus. The 0-15-H20-PET investigation revealed metabolic uncoupling along the rubroolivocerebellar loop. Given the delicate anatomy of the structures involved, image registration and standardized image analysis techniques are essential for a synoptic multimodality analysis of morphological and functional pathology and should generally be used for cerebral PET investigations.

Darstellung eines Nebennierenrindenkarzinoms und seiner Metastasen mit FDG-PET

Beschrieben wird der Fall einer jetzt 42jährigen Patientin, die zwei Wochen nach RO-Resektion eines Nebennierenrindenkarzinoms in der Nebennierenloge eine neuerliche ausgedehnte Raumforderung zeigte. Das rasche Wachstum ließ Zweifel an der Diagnose eines Lokalrezidivs aufkommen. In der PET-Untersuchung konnten neben einem großen Lokalrezidiv mehrere Lungen-als auch Lebermetastasen nachgewiesen werden, so daß auf eine operative Sanierung der Lungenfiliae verzichtet wurde. Die FDG-PET erscheint somit geeignet, in einer einzeitigen Untersuchung Nebennierenrindenkarzinome darzustellen und eine Ausbreitungsdiagnostik zu führen.

18F-FDG PET and conventional imaging for assessment of Hodgkin’s disease and non Hodgkin’s lymphoma

The aim of this study was to assess the diagnostic value of FDG-PET and conventional imaging (CI) in a large series of patient with Hodgkin’s disease (HD) or non-Hodgkin’s lymphoma (NHL) at three time points during their course of disease. Patients, methods: 169 consecutive lymphoma patients (69 HD; 100 NHL) were included. 193 FDG-PET studies were performed for staging at baseline in 42 cases, for post-therapeutic monitoring in 103, and for diagnosis of recurrence in 48 cases. Performance indices of sensitivity, specificity, positive (PPV) and negative predictive value (NPV), and accuracy of metabolic FDG-PET and morphological CI were calculated. Differences in staging and diagnosis of residual or recurrent lymphoma were compared. Results: FDG-PET changed staging in 36% of cases for staging at baseline, in 52% of cases for monitoring response to treatment, and in 29% for diagnosis of recurrence. FDG-PET staging results were confirmed in 80% for staging at baseline, in 74% for monitoring response to treatment, and in 50% for diagnosis of recurrence. FDGPET and CI differed significantly at monitoring response to treatment for sensitivity (0.91 versus 0.69; p<0.02), specificity (0.90 versus 0.38; p<0.00001), PPV (0.77 versus 0.42; p<0.001), and accuracy (0.83 versus 0.55; p<0.02). Conclusion: FDG-PET should be considered as the diagnostic modality of choice for post-therapeutic assessment of lymphoma patients and may be a reliable alternative to CI for staging at baseline and diagnosis of recurrence.

Guideline for in vivo- and in vitro procedures for thyroid diseases (version 2)

The version 2 of the guideline for diagnostic standards of thyroid disorders is an update of the guideline published in 1999 and describes standards of in vitro and in vivo procedures. The following statements are modified: In vitro procedures: When measurement of the TSH-receptor antibodies is indicated, the guideline recommends the use of a second generation assay (recombinant human TSH-receptor as antigen). The functional assay sensitivity for the measurement of thyroglobulin should reach a value ≤1 ng/ml. Moleculargenetic tests (RET proto-oncogen) are indicated in patients with a newly diagnosed medullary thyroid cancer and in the relatives of patients with hereditary medullary thyroid cancer. In vivo procedures: The sonographic examination should use a probe with a frequency of at least 7.5 MHz. Indications for the thyroid scintigraphy: nodule size ≥1 cm in diameter, autonomous goitre/nodule with clinical or subclinical hyperthyroidism, necessity of a differentiation between Graves’ disease and chronic lymphocytic thyroiditis, therapy control after a definitive treatment and – in individual cases – the follow-up of untreated autonomous nodules.

Guideline for radioiodine therapy for benign thyroid diseases (version 3)

The version 3 of the guideline for radioiodine therapy for benign thyroid diseases presents first of all a revision of the version 2. The chapter indication for radioiodine therapy, surgical treatment or antithyroid drugs bases on an interdisciplinary consensus. The manifold criteria for decision making consider the entity of thyroid disease (autonomy, Graves’ disease, goitre, goitre recurrence), the thyroid volume, suspicion of malignancy, cystic nodules, risk of surgery and co-morbidity, history of subtotal thyroidectomy, persistent or recurrent thyrotoxicosis caused by Graves’ disease including known risk factors for relapse, compression of the trachea caused by goitre, requirement of direct therapeutic effect as well as the patient’s preference. Because often some of these criteria are relevant, the guideline offers the necessary flexibility for individual decisions. Further topics are patients’ preparation, counseling, dosage concepts, procedural details, results, side effects and follow-up care. The prophylactic use of glucocorticoids during radioiodine therapy in patients without preexisting ophthalmopathy as well as dosage and duration of glucocorticoid medication in patients with preexisting ophthalmopathy need to be clarified in further studies. The pragmatic recommendations for the combined use of radioiodine and glucocorticoids remained unchanged in the 3rd version.

Radioisotope albumin flux measurement of microvascular lung permeability: an independent parameter in acute respiratory failure?

Aim: To evaluate the extent to which single measurements of microvascular lung permeability may be relevant as an additional parameter in a heterogenous clinical patient collective with Acute Lung Injury (ALI) and Acute Respiratory Distress Syndrome (ARDS). Methods: In 36 patients with pneumonia (13), non pneumogenic sepsis (9) or trauma (14) meeting the consensus conference criteria of ALI or ARDS double-isotope protein flux measurements (51Cr erythrocytes as intravascular tracer, Tc-99m human albumin as diffusible tracer) of microvascular lung permeability were performed using the Normalized Slope Index (NSI). The examination was to determine whether there is a relationship between the clinical diagnosis of ALI/ARDS, impaired permeability and clinical parameters, that is the underlying disease, oxygenation, duration of mechanical ventilation and mean pulmonary-artery pressure (PAP). Results: At the time of study, 25 patients presented with increased permeability (NSI > 1 × 10-3 min1) indicating an exudative stage of disease, and 11 patients with normal permeability. The permeability impairment correlated with the underlying disease (p >0.05). With respect to survival, there was a negative correlation to PAP (p <0.01). Apart from that no correlations between the individual parameters were found. Especially no correlation was found between permeability impairment and oxygenation, duration of disease or PAP. Conclusion: In ALI and ARDS, pulmonary capillary permeability is a diagnostic parameter which is independent from clinical variables. Permeability measurement makes a stage classification (exudative versus non exudative phase) of ALI/ARDS possible based on a measurable pathophysiological correlate.

Procedure guidelines for radioiodine therapy of differentiated thyroid cancer (version 2)

The procedure guidelines for radioiodine therapy (RIT) of differentiated thyroid cancer (version 2) are the counterpart to the procedure guidelines for 131I whole-body scintigraphy (version 2) and specify the interdisciplinary guidelines for thyroid cancer of the Deutsche Krebs-gesellschaft and the Deutsche Gesellschaft für Chirurgie concerning the nuclear medicine part. Compared with version 1 facultative options for RIT can be chosen in special cases: ablative RIT for papillary microcarcinoma ≤1 cm, ablative RIT for mixed forms of anaplastic and differentiated thyroid cancer, and RIT in patients with a measurable or increasing thyroglobulin concentration but without detectable metastases by imaging. The description of the pretherapeutic dosimetry now includes the isotopes 123I and 124I as well as a broader range of the activity of 131I. Activities of 2-5 GBq 131I are recommended for the first ablative RIT. If high accumulative activities of 131I are expected, men who have not yet finished their family planning should be advised to the option of sperm cryoconservation. An interdisciplinary consensus is necessary whether the new TNM-classification (UICC, 6th edition, 2002) will lead to modified recommendations for surgical or nuclear medicine therapy, especially for the surgical completeness and for the ablative RIT of pT1 papillary cancer.

PET with 18F-DOPA in the imaging of parathyroid adenoma in patients with primary hyperparathyroidism

Preoperative localization of parathyroid adenomas (PA) can shorten operation time and improve curative rate; it becomes especially important in minimally invasive surgical techniques. Aim of this study was to investigate whether positron emission tomography (PET) with 3-,4-dihydroxy- 6-18F-fluorophenylalanine (18F-DOPA), which showed very promising results in other neuroendocrine tumours, also helps to localize PA. Patients, methods: Eight patients with proven primary hyperparathyroidism were studied preoperatively with PET. Seven also underwent scintigraphy with 99mTc-MIBI and ultrasonography of the neck. All patients were operated and the histological finding was used as a gold standard. Results: All eight patients had a histologically proven PA. None of the PA showed any detectable uptake of 18F-DOPA. However, ultrasonography detected 5/7 PA, scintigraphy detected 3/7 PA. Conclusion: These results suggest that PET with 18F-DOPA is not useful in the detection of PA in patients with primary hyperparathyroidism.

Lymph node staging in extracranial head and neck cancer with FDG PET – appropriate uptake period and size-dependence of the results

Aim: Identification of a rationale for the appropriate uptake period for static clinical extracranial head and neck PET imaging and evaluation of the diagnostic accuracy of such an optimized FDG PET approach for lymph node staging in the head and neck region. Methods: In a subset of 5 patients, kinetic tumour studies were performed in order to identify the cellular activity plateau phase of FDG accumulation for head and neck cancer. Seventy-eight consecutive patients (11 women, 67 men; mean age ± SD: 55 ± 11 years; range, 36-78 years), presenting with histologically proven squamous cell carcinoma and sonographically detected lymph nodes in 86 neck sides, underwent clinically indicated FDG PET imaging. PET results were compared to those derived from histological examinations and follow-up imaging results after 6 months in order to calculate sensitivity and specificity for lymph node staging. Results: FDG kinetics in head and neck cancer indicate that the cellular activity plateau of FDG accumulation is reached after an uptake period of 90 min. Using this protocol metastatic involvement of neck sides with lymph nodes less than 1 cm in diameter was correctly identified with a sensitivity of 71.4% and a specificity of 92.3%. Sensitivity increased with the lymph node diameter (1.1-1.5 cm 83.3%, 1.6-2.0 cm 100%, > 2 cm 88.9%). Conclusion: The appropriate uptake period for static clinical extracranial head and neck PET imaging that allows measurements in the activity plateau phase is about 90 min. FDG PET may add some significant information regarding metastatic spread into regional lymph nodes.

Procedure guidelines for dynamic renal scintigraphy

This procedure guideline describes the procedures for dynamic renal scintigraphy with 99mTc-MAG3, 123I-hippuran and 99mTc-DTPA. Common clinical applications as well as a detailed description of the procedure are given. It also includes explanations and hints concerning the analysis, evaluation, interpretation, and presentation of the findings.

Ergebnisse der Radiojod-Behandlung autonomer Schilddrüsen-Adenome unter Berücksichtigung regionaler Jodkinetik und paranodulärer Speicherung

Bei 110 Patienten mit dekompensiertem autonomen Adenom der Schilddrüse wurde der Erfolg einer Radiojod-Therapie mit unterschiedlicher Herddosis (300 Gy, 400 Gy) überprüft. Zusätzlich wurden die relativen paranodulären Speicherungswerte vor und nach Radio-Therapie in Abhängigkeit von der Therapiedauer verglichen. Bei kurzer Therapiedauer (5-8 Tage) sinkt die paranoduläre Speicherung ab, während sie bei langer Therapiedauer (9-20 Tage) zunimmt. Dadurch ist die bei langer Therapiedauer nachweisbare höhere Hypothyreoserate (14%) erklärbar. Die Ausschaltquote betrug bei einer Herddosis von 300 Gy 93,6%, bei 400 Gy waren es 95%. Dagegen fand sich bei einer Herddosis von 300 Gy eine geringere (3,2%) Hypothyreoseinzidenz als bei 400 Gy (8,8%). Trotzdem sollte zur Verminderung der Versagerquote die höhere Herddosis gewählt werden. Wegen des Ansteigens der Hypothyreoserate mit zunehmender paranodulärer Speicherung empfiehlt sich in Fällen von paranodulären Speicherungswerten zwischen 10 und 20% (sogenannter Übergangstyp) eine exogene Suppression mit Schilddrüsenhormon.

Die Funktionsszintigraphie der Lungenventilation mit 133Xe bei juveniler Skoliose

An 20 Kindern mit ausgeprägter Skoliose wurde vor geplanter Korrekturoperation nach Harrington eine Spirometrie, Röntgenuntersuchung der Lunge sowie eine Lungenfunktionsszintigraphie mit 133Xe durchgeführt. Bei der Szintigraphie wurden prozentuale Verteilung der funktionellen Residualkapazität (FRC) und die Auswaschkurven mit den Parametern: 3-Min.-Retention vor Untergrundkorrektur, der mittleren Zeitkonstante und dem Effektivitätsindex nach Untergrundkorrektur quantitativ ausgewertet. Während die Röntgenbilder sowie die single breath-Phase der Funktionsszintigraphie meist unauffällig blieben, zeigte die Verschiebung der prozentualen FRC-Verteilung zur Konkavseite der Skolioselunge in allen Fällen eine regionale restriktive Ventilationsstörung der Konvexseite an, während die Analyse der Auswaschkurven darüber hinaus ausgeprägte regionale alveoläre Ventilationsstörungen der Konvexseite der Skolioselunge nachwies. Auch in den Fällen, in denen die Spirometrie unauffällig blieb, waren alle Parameter schon gering pathologisch, was am ehesten auf eine schon vorliegende Beeinträchtigung der Lungenfunktion durch die Skoliose zurückzuführen ist. Der Effektivitätsindex, der bei den Auswaschkurven die Atemfrequenz, das Atemzugsvolumen, die funktionelle Residualkapazität und einen Totraumanteil berücksichtigt, erwies sich als der genaueste und empfindlichste Parameter regionaler alveolärer Abatmungsstörungen.

Effects of Obstruction on Single-Kidney Function Clinical and Experimental Results with 131I-Hippurate and 99mTc-DMSA

In 35 patients, renography with 131I-o-hippurate (OIH) and static renal imaging with 99mTc-dimercaptosuccinic acid (DMSA) were used to measure differential renal function (DRF). The results were compared. Depth correction was applied in both methods. In non-obstructed kidneys (19 patients), both methods revealed nearly identical kidney function (r = 0.98). For completely obstructed kidneys (16 patients), OIH gave a significantly better DRF (14 ml/min) than DMSA. This small difference was of no clinical value. Because DMSA is reported to give unreliable results in unilateral obstructed kidneys, the right ureter was ligated in 8 dogs for 10 days and DRF was measured before and after opening an ureteral fistula. The difference in DRF was about 1% and could be accounted for by the amount of urinary radioactivity collected from the pelvic system after the ligature had been opened. Although DMSA appears to give reliable values in determining DRF, even in obstructed kidneys, OIH is preferred since total clearance values and postrenal urinary dynamics can be determined simultaneously.

Guideline for radioiodine therapy for benign thyroid diseases (version 4)

Version 4 of the guideline for radioiodine therapy for benign thyroid diseases includes an interdisciplinary consensus on decision making for antithyroid drugs, surgical treatment and radioiodine therapy. The quantitative description of a specific goiter volume for radioiodine therapy or operation was cancelled. For patients with nodular goiter with or without autonomy, manifold circumstances are in favor of surgery (suspicion on malignancy, large cystic nodules, mediastinal goiter, severe compression of the trachea) or in favor of radioiodine therapy (treatment of autonomy, age of patient, co-morbidity, history of prior subtotal thyroidectomy, profession like teacher, speaker or singer). For patients with Graves' disease, radioiodine therapy or surgery are recommended in the constellation of high risk of relapse (first-line therapy), persistence of hyperthyroidism or relapse of hyperthyroidism. After counseling, the patient gives informed consent to the preferred therapy. The period after radioiodine therapy of benign disorders until conception of at least four months was adapted to the European recommendation.

Procedure guidelines for radioiodine therapy of differentiated thyroid cancer (version 3)

The procedure guideline for radioiodine therapy (RIT) of differentiated thyroid cancer (version 3) is the counterpart to the procedure guideline for 131I whole-body scintigraphy (version 3) and specify the interdisciplinary guideline for thyroid cancer of the Deutsche Krebsgesellschaft concerning the nuclear medicine part. Recommendation for ablative 131I therapy is given for all differentiated thyroid carcinoma (DTC) >1 cm. Regarding DTC ≤1 cm 131I ablation may be helpful in an individual constellation. Preparation for 131I ablation requires low iodine diet for two weeks and TSHstimulation by withdrawal of thyroid hormone medication or by use of recombinant human TSH (rhTSH). The advantages of rhTSH (no symptoms of hypothyroidism, lower blood activity) and the advantages of endogenous TSHstimulation (necessary for 131I-therapy in patients with metastases, higher sensitivity of 131I whole-body scan) are discussed. In most centers standard activities are used for 131I ablation. If pretherapeutic dosimetry is planned, the diagnostic administration of 131I should not exceed 1–10 MBq, alternative tracers are 123I or 124I. The recommendations for contraception and family planning are harmonized with the recommendation of ATA and ETA. Regarding the best possible protection of salivary glands the evidence is insufficient to recommend a specific setting. To minimize the risk of dental caries due to xerostomia patients should use preventive strategies for dental hygiene.

Impact of self-esteem and sex on stress reactions

Positive self-evaluation is a major psychological resource modulating stress coping behavior. Sex differences have been reported in self-esteem as well as stress reactions, but so far their interactions have not been investigated. Therefore, we investigated sex-specific associations of self-esteem and stress reaction on behavioral, hormonal and neural levels. We applied a commonly used fMRI-stress task in 80 healthy participants. Men compared to women showed higher activation during stress in hippocampus, precuneus, superior temporal gyrus (STG) and insula. Furthermore, men outperformed women in the stress task and had higher cortisol and testosterone levels than women after stress. Self-esteem had an impact on precuneus, insula and STG activation during stress across the whole group. During stress, men recruit regions associated with emotion and stress regulation, self-referential processing and cognitive control more strongly than women. Self-esteem affects stress processing, however in a sex-independent fashion: participants with lower self-esteem show higher activation of regions involved in emotion and stress regulation, self-referential processing and cognitive control. Taken together, our data suggest that men are more engaged during the applied stress task. Across women and men, lower self-esteem increases the effort in emotion and stress processing and cognitive control, possibly leading to self-related thoughts in stressful situations.

In vivo MRI of the human finger at 7 T

Purpose

To demonstrate a dedicated setup for ultrahigh resolution MR imaging of the human finger in vivo.

Methods

A radiofrequency coil was designed for optimized signal homogeneity and sensitivity in the finger at ultrahigh magnetic field strength (7 T), providing high measurement sensitivity. Imaging sequences (2D turbo‐spin echo (TSE) and 3D magnetization‐prepared rapid acquisition gradient echo (MPRAGE)) were adapted for high spatial resolution and good contrast of different tissues in the finger, while keeping acquisition time below 10 minutes. Data was postprocessed to display finger structures in three dimensions.

Results

3D MPRAGE data with isotropic resolution of 200 µm, along with 2D TSE images with in‐plane resolutions of 58 × 78 µm² and 100 × 97 µm², allowed clear identification of various anatomical features such as bone and bone marrow, tendons and annular ligaments, cartilage, arteries and veins, nerves, and Pacinian corpuscles.

Conclusion

Using this dedicated finger coil at 7 T, together with adapted acquisition sequences, it is possible to depict the internal structures of the human finger in vivo within patient‐compatible measurement time. It may serve as a tool for diagnosis and treatment monitoring in pathologies ranging from inflammatory or erosive joint diseases to injuries of tendons and ligaments to nervous or vascular disorders in the finger. Magn Reson Med 79:588–592, 2018. © 2017 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Interleaved multivoxel 31 P MR spectroscopy

PURPOSE

Separate measurements are required when investigating multiple exercising muscles with singlevoxel-localized dynamic 31 P-MRS. With multivoxel spectroscopy, 31 P-MRS time-series spectra are acquired from multiple independent regions during one exercise-recovery experiment with the same time resolution as for singlevoxel measurements.

METHODS

Multiple independently selected volumes were localized using temporally interleaved semi-LASER excitations at 7T. Signal loss caused by mutual saturation from shared excitation or refocusing slices was quantified at partial and full overlap, and potential contamination was investigated in phantom measurements. During an exercise-recovery experiment both gastrocnemius medialis and soleus of two healthy volunteers were measured using multivoxel acquisitions with a total TR of 6 s, while avoiding overlap of excitation slices.

RESULTS

Signal reduction by shared adiabatic refocusing slices selected 1 s after the preceding voxel was between 10% (full overlap) and 20% (half overlap), in a phantom measurement. In vivo data were acquired from both muscles within the same exercise experiment, with 13-18% signal reduction. Spectra show phosphocreatine, inorganic phosphate, adenosine-triposphate, phosphomonoesters, and phosphodiesters.

CONCLUSION

Signal decrease was relatively low compared to the 2-fold increase in information. The approach could help to improve the understanding in metabolic research and is applicable to other organs and nuclei. Magn Reson Med 77:921-927, 2017. © 2016 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.