Kontinuierliche Sensitivitätssteigerung in der Schilddrüsenkarzinom-Nachsorge im Verlauf dreier Thyreoglobulin-IMA-Generationen

Aim of our study was to evaluate the increasing sensitivity within three generations of thyroglobulin (Tg) as-says, which were available during the past decade, and its clinical impact for patients with differentiated thyroid carcinoma. Methods: Determination of Tg using the IRMA introduced in 1989 (Dynotest®Tg, Henning Berlin, Berlin; assay A) and 1994 (Selco®Tg, Medipan Diagnostica, Selchow; assay B), as well as the IEMA available recently (Medizym®Tg Rem, Medipan Diagnostica, Selchow; assay C). Results: We found a close correlation between the measurable Tg values of assay A and B (r = 0.985; p <0.001) as well as assay B and C (r = 0.978; p <0.001). Assay B (lowest detection limit: 0.3 ng/ml) was more than twice as sensitive as assay A and did not show quite as many disturbances of recovery (in 0.5% versus 4% of our patients). Due to its strict calibration to the European reference preparation CRM 457, Tg values determined by assay C were in the mean 1.9-fold higher than by assay B. Thus, with its functional sensitivity of 0.03 ng/ml assay C is nearly 20-fold more sensitive than assay B. Whereas the proportion of measurable Tg values was only 22% in a selected group of patients (criterion of inclusion: Tg in assay B ≤1 ng/ml with TSH-suppressive conditions; n = 317 serum samples from 103 patients), it was 68% in assay C, with good intraindividual reproducibility of these values in the course. Conclusion: The ultrasensitive assay C is especially suitable for the follow-up of treated thyroid cancer patients being considered as cured, and may shorten the time interval until the detection of a recurrence markedly: the gain of time calculated from the Tg courses in patients with a gradually progressive tumor relapse ranged from 5 to 15 months.

High mutation detection rates in cerebral cavernous malformation upon stringent inclusion criteria: one-third of probands are minors

Cerebral cavernous malformations (CCM) are prevalent vascular malformations occurring in familial autosomal dominantly inherited or isolated forms. Once CCM are diagnosed by magnetic resonance imaging, the indication for genetic testing requires either a positive family history of cavernous lesions or clinical symptoms such as chronic headaches, epilepsy, neurological deficits, and hemorrhagic stroke or the occurrence of multiple lesions in an isolated case. Following these inclusion criteria, the mutation detection rates in a consecutive series of 105 probands were 87% for familial and 57% for isolated cases. Thirty-one novel mutations were identified with a slight shift towards proportionally more CCM3 mutations carriers than previously published (CCM1: 60%, CCM2: 18%, CCM3: 22%). In-frame deletions and exonic missense variants requiring functional analyses to establish their pathogenicity were rare: An in-frame deletion within the C-terminal FERM domain of CCM1 resulted in decreased protein expression and impaired binding to the transmembrane protein heart of glass (HEG1). Notably, 20% of index cases carrying a CCM mutation were below age 10 and 33% below age 18 when referred for genetic testing. Since fulminant disease courses during the first years of life were observed in CCM1 and CCM3 mutation carriers, predictive testing of minor siblings became an issue.

Lovastatin improves impaired synaptic plasticity and phasic alertness in patients with neurofibromatosis type 1

Background

Neurofibromatosis type 1 (NF1) is one of the most common genetic disorders causing learning disabilities by mutations in the neurofibromin gene, an important inhibitor of the RAS pathway. In a mouse model of NF1, a loss of function mutation of the neurofibromin gene resulted in increased gamma aminobutyric acid (GABA)-mediated inhibition which led to decreased synaptic plasticity and deficits in attentional performance. Most importantly, these defictis were normalized by lovastatin. This placebo-controlled, double blind, randomized study aimed to investigate synaptic plasticity and cognition in humans with NF1 and tried to answer the question whether potential deficits may be rescued by lovastatin.

Methods

In NF1 patients (n = 11; 19–44 years) and healthy controls (HC; n = 11; 19–31 years) paired pulse transcranial magnetic stimulation (TMS) was used to study intracortical inhibition (paired pulse) and synaptic plasticity (paired associative stimulation). On behavioural level the Test of Attentional Performance (TAP) was used. To study the effect of 200 mg lovastatin for 4 days on all these parameters, a placebo-controlled, double blind, randomized trial was performed.

Results

In patients with NF1, lovastatin revealed significant decrease of intracortical inhibition, significant increase of synaptic plasticity as well as significant increase of phasic alertness. Compared to HC, patients with NF1 exposed increased intracortical inhibition, impaired synaptic plasticity and deficits in phasic alertness.

Conclusions

This study demonstrates, for the first time, a link between a pathological RAS pathway activity, intracortical inhibition and impaired synaptic plasticity and its rescue by lovastatin in humans. Our findings revealed mechanisms of attention disorders in humans with NF1 and support the idea of a potential clinical benefit of lovastatin as a therapeutic option.

[Scintigraphically "hot" thyroid nodules mainly go hand in hand with a normal TSH]

AIM

In recent years, various professional societies published guidelines for diagnostic evaluation of thyroid nodules, in which the indication for scintigraphy is restricted to patients with subnormal TSH values. It is seen controversial whether such recommendations should be transferred to Germany, partly because of lower iodine intake in this country and the consequent higher percentage of autonomous thyroid nodules, which are not accompanied by a measurable dysfunction. Since reliable data to this topic are scarce, we analyzed multicentrically the spectrum of scintigraphically "hot" and "warm" nodules under the current epidemiological conditions.

PATIENTS, METHODS

In 10 German nuclear medicine out-patient institutions we evaluated the diagnostic data from a total of 514 patients, in whom unequivocally hyperfunctional nodules (focal increased uptake in comparison to perinodular tissue with a sonographically nodular correlative ≥1 cm) could be detected by (99m)Tc-pertechnetate scintigraphy. To minimize selection bias, the surveys were not carried out in hospitals.The recorded parameters included the thyroid hormone levels, the global (99m)Tc-uptake (TcTU), the size of each nodule and the total autonomous nodular volume (V(aut)).

RESULTS

Only 20% of the patients with "hot" nodules had subnormal TSH levels (<0.1 to 0.33 mU / l), the remaining patients had TSH levels from 0.34 to 3.5 mU /l (in one third of the patients TSH levels even exceeded 1.0 mU/l). Moreover, we found no relevant correlation between TSH and TcTU or V(aut).

CONCLUSIONS

In Germany, in at far the largest proportion of patients with autonomous thyroid nodules objectified by means of scintigraphy, TSH levels are within the normal range. Since such nodules with maximum safety can be classified as benign, a corresponding scintigraphic finding has a high priority for the patient. These current data support that it is not reasonable to restrict scintigraphy to patients with subnormal TSH values in this country.

Quantitative imaging of (124)I with PET/ CT in pretherapy lesion dosimetry. Effects impairing image quantification and their corrections

Iodine-131-labelled agents are successfully used in cancer treatment. In the pretherapy dosimetry approach, positron emission tomography/computed tomography (PET/CT) using (124)I provides a modality to estimate absorbed dose to tumours and can be considered as the preferred imaging method for this purpose in (131)I radiopharmaceutical therapies. For accurate dosimetry, serial measurements of activity concentrations (ACs) over an appropriate time period are necessary. Consequently, accurate AC determination is of paramount importance in PET/CT-based lesion dosimetry using (124)I-labelled agents. After presenting an historical overview of (124)I clinical application, this review focuses on factors impairing PET image quantification accuracy and on methods of correcting for these effects. Specifically, the emission of prompt gamma photons in the (124)I decay process that are detected in coincidence with each other and with the annihilation photon, and the low (124)I positron branching ration of only 23% raise concerns regarding image quantification accuracy. This review discusses this prompt gamma effect, its impact and approaches to correct for this phenomenon. In (124)I lesion dosimetry, recovery coefficients (RCs) are commonly used to compensate primarily for partial-volume effect but also, in a simplistic way, for prompt gamma coincidence effect; the main methodological factors affecting the RC-corrected (124)I AC are described. Finally, special issues in image (124)I quantification are reviewed, including coadministration of high therapeutic activities of 131I, shine-through artefact, and transmission-contamination effect occurring in stand-alone PET systems.

Cervical lymph node metastases of unknown origin: primary tumor detection with whole-body positron emission tomography/computed tomography

BACKGROUND

Identification of primary tumor in patients with cervical lymph node metastasis of unknown primary (MUO) has a great impact on therapy approach and potentially on patient prognosis.

PURPOSE

To assess the diagnostic accuracy of combined positron emission tomography(PET)/computer tomography (CT) for primary tumor detection in cervical metastases of unknown origin compared to PET, CT, and PET+CT side-by-side evaluation.

MATERIAL AND METHODS

39 consecutive patients (eight women, 31 men; mean age 59.9 ± 11.2 years) with MUO were enrolled in this study. PET/CT images were obtained 1 hour after injection of 350 MBq of fluorodeoxyglucose. Oral and intravenous contrast agents were administered in all patients to ensure diagnostic CT data. Fused PET/CT data were evaluated for primary tumor detection. Diagnostic accuracy was calculated and compared with CT alone, PET alone, and side-by-side PET+CT evaluation.Statistical analysis of differences in diagnostic performance between the different imaging procedures was based on the McNemar test.

RESULTS

Fused PET/CT depicted the primary tumor in 11 of 39 (28%) patients. In 28(72%) patients, the primary tumor remained occult. CT revealed the primary in five(13%), PET alone in 10 (26%), and side-by-side evaluation of PET+CT in 10 (26%) of 39 patients. Statistical analysis showed no significant differences between the imaging modalities.

CONCLUSION

PET, side-by-side PET+CT, and PET/CT revealed similar detection rates for primary tumors in cervical MUO patients. Therefore, cervical metastases of an unknown primary may be assessed with either of these imaging modalities. Detection rates with CT were substantially lower. Thus, inclusion of functional data for assessment of cervical MUO patients must be recommended.

[Continously increasing sensitivity in thyroid cancer aftercare in the course of three generations of thyroglobulin IMAs]

Aim of our study was to evaluate the increasing sensitivity within three generations of thyroglobulin (Tg) assays, which were available during the past decade, and its clinical impact for patients with differentiated thyroid carcinoma.

METHODS

Determination of Tg using the IRMA introduced in 1989 (Dynotest Tg, Henning Berlin, Berlin; assay A) and 1994 (Selco Tg, Medipan Diagnostica, Selchow; assay B), as well as the IEMA available recently (Medizym Tg Rem, Medipan Diagnostica, Selchow; assay C).

RESULTS

We found a close correlation between the measurable Tg values of assay A and B (r=0.985; p<0.001) as well as assay B and C (r=0.978; p<0.001). Assay B (lowest detection limit: 0.3 ng/ml) was more than twice as sensitive as assay A and did not show quite as many disturbances of recovery (in 0.5% versus 4% of our patients). Due to its strict calibration to the European reference preparation CRM 457, Tg values determined by assay C were in the mean 1.9-fold higher than by assay B. Thus, with its functional sensitivity of 0.03 ng/ml assay C is nearly 20-fold more sensitive than assay B. Whereas the proportion of measurable Tg values was only 22% in a selected group of patients (criterion of inclusion: Tg in assay B< or =1 ng/ml with TSH-suppressive conditions; n=317 serum samples from 103 patients), it was 68% in assay C, with good intraindividual reproducibility of these values in the course.

CONCLUSION

The ultrasensitive assay C is especially suitable for the follow-up of treated thyroid cancer patients being considered as cured, and may shorten the time interval until the detection of a recurrence markedly: the gain of time calculated from the Tg courses in patients with a gradually progressive tumor relapse ranged from 5 to 15 months.

Influence of therapy with iodine-131 on thyroid tissue pattern in colour and power Doppler sonography

AIM

The aim of this study was to evaluate the influence of radioiodine therapy on sonographic thyroid patterns using power Doppler (PD) and colour Doppler (CD) sonography in hyperthyroid patients with autonomous nodules (AN) and Graves' disease (GD).

METHOD

B-mode, colour, and power Doppler sonography, (99m)Tc scintigraphy, and laboratory analyses (free thyronine fT(3), free thyroxine fT(4), thyroid stimulating hormone TSH) were performed in 55 patients (AN = 27, GD = 28) before and 6 months following therapy with (131)I radioiodine therapy (RIT).

RESULTS

In patients with an AN (but not in GD), a significant reduction in thyroid vascularization was subjectively noted following radioiodine therapy on both CD and PD ultrasound (Wilcoxon matched pairs, P < 0.05). The pre-therapeutic grade of hypervascularization in the periphery of autonomous nodules correlated closely with the laboratory parameters of hyperthyroidism. As expected, PD indicated a higher grade of vascularization when compared with CD due to its greater sensitivity to flow.

CONCLUSIONS

Radioiodine therapy led to a significant reduction in hypervascularization in patients with AN (but not in GD) corresponding to the normalization of serological values. Comparing CD and PD, PD detected a greater number of vessels. CD and PD are not able to replace scintigraphy and/or laboratory analyses in the management of patients with hyperthyroidism.

[Evaluation of myocardial viability with contrast-enhanced magnetic resonance imaging--comparison of the late enhancement technique with positronemission tomography]

PURPOSE

To compare contrast-enhanced magnetic resonance imaging (MRI) and positron emission tomography (PET) in the evaluation of myocardial viability.

METHODS

[ (18)F]-FDG-PET, [ (201)Tl]-TlCl-SPECT and contrast-enhanced MRI were performed in 29 patients with proven coronary artery disease and impaired left ventricular function to assess myocardial viability. MRI scans were done on a 1.5 T scanner (Magnetom Sonata, Siemens, Germany). After the steady-state free precession cine study, 0.2 mmol/kg BW of Gd-DPTA (Magnevist(R), Schering, Germany) were administered i. v. For the detection of "late enhancement" (LE) indicating scar, left ventricular long axes and contiguous short axis slices of 8 mm thickness were scanned using an inversion recovery turbo gradient echo sequence (TR 8.0 ms; TE 4.0 ms; TI 180 - 240 ms; FA 20 degrees ). The evaluation of LE and FDG uptake in PET with perfusion defect in SPECT was done using an 8 (basal, mid) and 4 (apical) segment model in all short axes to cover the entire ventricle. The transmural extent of LE was assessed using a 4-point score system. Comparison between the two modalities was performed on a segmental basis.

RESULTS

A total of 1753 segments were assessed. In MRI, 40 % of the segments showed myocardial scar, whereas PET revealed impaired uptake in 25 %. MRI obtained a very low interobserver variability in detecting myocardial scar (kappa 0.92). Using PET as the standard of reference in the segmental comparison, contrast-enhanced MRI yielded a sensitivity of 84 % and a specificity of 76 % for the detection of scar. 18 % of all segments showed LE but normal FDG uptake, 83 % of them referred to subendocardial scars.

CONCLUSIONS

There is close agreement between contrast-enhanced MRI and PET in detecting transmural myocardial scars. Superior spatial resolution enables MRI to detect and quantify even subendocardial scar. Therefore, larger studies using functional recovery after revascularisation as an endpoint have to prove whether MRI might replace PET as the standard of reference in the assessment of myocardial viability.

SPECT imaging with [123I]-beta-CIT in Parkinsonism: comparison of SPECT images obtained by a single-headed and a three-headed gamma camera

Single photon emission computed tomography (SPECT) imaging of dopamine transporters by using the cocaine derivative [123I]-(1R)-2-beta-carbomethoxy-3-beta-(4-iodophenyl)-tropane ([123I]-beta-CIT) has been shown to be useful in patients with Parkinsonism. The aim of this study was to compare beta-CIT imaging with single-headed (SHS) and three-headed gamma camera systems (THS). In 17 patients with Parkinsonism, SPECT imaging with an SHS and a THS was performed 24 h after injection of 180 MBq of [123I]-beta-CIT. The SPECT studies were evaluated by visual assessment of the caudate nucleus (CN) and the putamen (PT) and the calculation of the striatal/cerebellar (S/C) ratios (with additional comparison to clinical symptoms measured by the Unified Parkinson's Disease Rating Scale (UPDRS)). The S/C ratios measured by the SHS and THS showed highly significant correlation (two-tailed P < 0.01) with Spearman correlation coefficients (SCCs) of 0.864 for the right side, 0.676 for the left side, and 0.761 for both sides. By the SHS, a sufficient visual differentiation between the CN and the PT could not be achieved. A significantly better distinction could be achieved by using the THS (Wilcoxon P<0.05). The S/C ratios of the THS only showed a significant (P < 0.05) SCC of -0.514 comparing to the UPDRS. Pathological alterations in the beta-CIT uptake pattern could be identified by using the SHS, but a significantly better differentiation of CN and the PT was possible by using the THS. The significant correlation of the S/C ratios measured by THS only emphasizes the value of THS in beta-CIT imaging.

Selective neck dissection in the management of squamous cell carcinoma of the upper digestive tract

Selective neck dissection has been used clinically in elective treatment of carcinoma, although many surgeons continue to advocate modified radical or radical neck dissection for therapeutic management of the neck. In a retrospective study 167 previously untreated patients were reviewed following curative laser microsurgical resections of oral or pharyngeal primary tumors and a unior bilateral selective neck dissection. In all, 221 (54 bilateral) neck dissections were performed. In patients with oral primary disease lymph nodes of levels I-III were removed, while nodes in levels II and III were removed in patients with pharyngeal tumors. Level IV was dissected when several metastases were suspected during operation. The posterior triangle was not dissected. Lymph nodes were histopathologically negative in 73 patients and positive in 94 patients. Twenty-five of these latter cases had pN1 disease, 55 had pN2b disease and 10 had bilateral lymph node metastases. Twenty patients in the pN0 group and 63 patients in the pN+ group received postoperative radiotherapy (to 56.7 Gy to the primary site and 52.5 Gy to the neck). With a median follow-up interval of 34 months, recurrence in the dissected neck occurred in 3 of 73 patients (4.1%) with pN0 disease and 6 of 90 patients (6.6%) with pN+ necks. Four patients with pN+ necks had simultaneous recurrences at the primary site. The addition of adjuvant radiotherapy seemed to improve disease control in the neck and improve overall survival in patients with an unfavorable prognosis due to multiple metastases or metastases with extracapsular spread.