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Summary Aim: To evaluate the influence of the introduction of combined PET/CT scanners into clinical routine. This investigation addresses the quantitative changes between PET/CT and stand alone PET. Methods: The study included all examinations performed on stand alone PET- or PET/CTscanners within 12 month prior to and after implementation of PET/CT. The final data analysis included five university hospitals and a total number of 15 497 exams. We distinguished exams on stand alone tomographs prior to and after installation of the combined device as well as PET/CT scans particularly with regard to disease entities. Various further parameters were investigated. Results: The overall number of PET scans (PET and PET/CT) rose by 146% while the number of scans performed on stand alone scanners declined by 22%. Only one site registered an increase in stand alone PET. The number of exams for staging in oncology increased by 196% while that of cardiac scans decreased by 35% and the number of scans in neurology rose by 47%. The use of scans for radiotherapy planning increased to 7% of all PET/CT studies. The increase of procedures for so-called classic PET oncology indications was moderate compared to the more common tumors. An even greater increase was observed in some rare entities. Conclusions: The introduction of PET/CT led to more than a doubling of overall PET procedures with a main focus on oncology. Some of the observed changes in scanning frequency may be caused by a rising availability of new radiotracers and advancements of competing imaging methods. Nevertheless the evident increase in the use of PET/CT for the most common tumour types demonstrates its expanding role in cancer staging. The combination of molecular and morphologic imaging has not only found its place but is still gaining greater importance with new developments in technology and radiochemistry.

SummaryWith about 4 million diabetics in germany and presumed inclination over the following years the treatment of diabetic complications like diabetic foot will become an even more important point. The management of Charcot’s foot has undergone fundamental change in the last few years. Formerly, treatment was almost exclusively limited to non surgical measures; since the late 1990’s, however, current practice has shifted to early, stage-appropriate surgical therapy. The aim of the present prospective study was to investigate the value of positron emission tomography (PET) in the pre-operative work-up of Charcot’s foot. PET were compared to magnetic resonance tomography (MRI). Patients, methods: MRI and PET imaging were used as part of the preoperative work-up in 18 patients with Type II diabetes mellitus. The diagnosis of Charcot’s foot requiring surgical treatment were made on the basis of clinical and radiologic criteria. Results: Of 46 Charcot’s lesions confirmed at surgery, 44 and 35 were detected by means of PET and MRI, respectively. PET can be used in the work-up of patients with metal implants where the MRI does not show adequate findings. PET shows the areas of detritus formation exhibit only moderately increased glucose metabolism and at visual interpretation do not usually impress as typical for acute osteomyelitis. Average SUV values stood at 1.2 (range: 0.5–2.9). Conclusions: The differentiation between Charcot’s lesions and florid osteomyelitis provides the surgeon with important additional information, which is often unavailable from MRI. Because of this important additional data, PET could be considered preferable to morphologic imaging (CT, projection radiography) in the preoperative work-up of Charcot’s foot.

ZusammenfassungIn der Initialdiagnostik bei rheumatoider Arthritis (RA) werden neben der Projektionsradiographie (PR) auch die Magnetresonanztomographie (MRT) und die 3-PhasenSkelettszintigraphie (3P-SZ) eingesetzt. Ziel dieser Studie war es, bei Patienten mit Verdacht auf RA die Wertigkeit der PR, der 3P-SZ und der MRT anhand von Verlaufsbeobachtungen über 2 Jahre zu beurteilen. Patienten, Methoden: Bei 42 Patienten wurden am selben Tag je eine 3P-SZ, Niederfeld-MRT und PR der Hände im dorsovolaren Strahlengang durchgeführt. Verlaufskontrollen erfolgten im jährlichen Abstand. Alle Bilder wurden von jeweils zwei erfahrenen Radiologen/ Nuklearmedizinern befundet und in rheumatypisch und nicht rheumatypisch unterteilt. Als Goldstandard diente die abschließende klinische Diagnose des Rheumatologen unter Berücksichtigung des Ritchie-articular-Index. Ergebnisse: Bei 24/42 Patienten wurde die Diagnose einer initialen RA gestellt. In der PR konnte bei 20/ 24 Patienten im zeitlichen Verlauf die richtige Diagnose gestellt werden. Demgegenüber wurde sowohl in der 3P-SZ als auch in der MRT bei allen 24 Patienten eine beginnende RA erkannt. Lediglich im Detektionszeitpunkt gab es Variationen mit insgesamt tendenziell späterer Diagnosestellung in der PR. Schlussfolgerung: In der bildgebenden Initialdiagnostik der RA ist die PR weiterhin als Verfahren der ersten Wahl anzusehen. In der weiterführenden Diagnostik von unklaren Befunden stellt die Niederfeld-MRT ein der 3P-SZ annähernd vergleichbar sensitives Verfahren dar. Trotzdem sollten – wenn möglich – aufgrund des geringen Field-of-view neben der 3P-SZ zur weiteren Abklärung unklarer Befunde Hochfeldtomographen bevorzugt werden.

AIM Correct staging of head and neck cancer is important for the patient's prognosis and further therapeutic strategies. Aim of the present study was to investigate the diagnostic value of FDG-PET regarding the pre-surgical diagnosis of primary tumor and cervical lymph node metastases, the diagnosis of tumour recurrence, and the localisation of unknown primary, further to compare the results to those of morphological imaging modalities (CT/MRI) and to correlate the results of both methods with histopathological findings. PATIENTS/METHODS 115 patients (pts) (72 x primary diagnosis, 37 x recurrence, and 6 x unknown primary) underwent FDG-PET (ECAT EXACT HR+) and CT or MRI. Results were correlated with histopathological findings in terms of detection of primary and recurrent tumors as well as lymph node metastases. RESULTS Regarding the pre-surgical diagnosis, sensitivity and specificity for identifying primary tumors were 85 % and 100 % for PET and 88 % and 75 % for CT/MRI, respectively. Accuracy was 86 % for PET and 87 % for CT/MRI. Sensitivity and specificity for detecting primary lymph node involvement were 71 %/86 % for PET and 74 %/57 % for CT/MRI, resulting in an accuracy of 77 % with PET and 68 % with morphological imaging. In 23 pts histopathology revealed pT1 stages with tumor diameters < 12 mm. In 8 pts CT/MRI and in 10 pts PET failed to identify these small primary lesions. Detecting tumor recurrence (n = 37) PET showed a higher sensitivity (83 %), specificity (76 %) and accuracy (78 %) compared to CT/MRI (sensitivity: 67 %; specificity: 52 %; accuracy: 57 %). In 4/6 pts with unknown primary, imaging was able to identify a primary lesion (3/4 in FDG-PET, 2/4 in CT/MRI), in 2/6 patients even in the follow-up no primary tumor was found. CONCLUSIONS FDG-PET provides only minor additional information to morphological imaging concerning diagnosis of primary tumors. At a similar level of sensitivity, however, it seems to be more specific regarding the lymph node involvement. PET seems to be superior to CT/MRI in detecting tumor recurrence as well as occult primary tumors in pts with known cervical lymph node metastases.

Summary Aim: Until now scintimammography did not achieve any definite role in the assessment of breast lesions. Purpose of this study was to elaborate its use as well as the limitations of scintimammography after 500 examinations completed. Methods: Scintigraphic findings were correlated with the histopathologic outcome of 219 patients, who underwent surgery or biopsy for histopathological confirmation. The results were determined with respect to palpability of the lesion and tumour size. Additionally, a distinct analysis was performed for the patient subpopulation with indeterminate results of previously performed physical examination, mammography, and sonography. Results: Overall sensitivity for scintimammography was 82.1% at a specificity of 87.5%. For palpable lesions sensitivity was 91.7% which was evidently higher as compared to 64.9% for non palpable lesions. For palpable lesions specificity was 81.1% and 88.6% for non palpable lesions. According to tumour size sensitivity ranged between 65.2% for carcinoma with a diameter 1 cm. In the patients subgroup with indeterminate preliminary diagnosis (n = 143) sensitivity decreased to 71.7% at a specificity of 87.8%. Patients undergoing neoadjuvant chemotherapy showed decreasing sestamibi uptake as early as 8 days after therapy if tumour response was evident. However, small residual invasive tumours in patients with complete remission could not be visualised. Conclusion: Scintimammography is neither suited for screening, nor early diagnosis of breast cancer, nor for the further evaluation of small and unclear mammographic findings. Scintimammography should not be used whenever histopathological clarification of a suspicious lesion is necessary. It is useful to further investigate patients with unclear or probably benign findings in physical examination and/or mammography and to monitor tumour response to neoadjuvant chemotherapy.

Eine 60jahrige Patientin mit einem 9 Monate zuvor resezierten Nebenschilddrusen-Karzinom wurde mit Muskelschwache, Polyurie, Polydipsie und unstillbarem Erbrechen in somnolentem Zustand stationar aufgenommen. Bei der klinischen Untersuchung imponierten eine deutliche Dehydratation, Paresen der Extremitatenmuskulatur sowie eine Hyperreflexie. Laborchemisch bestand eine schwere Hyperkalzamie und ein Hyperparathyreoidismus. Morphologische Untersuchungen zeigten drei Raumforderungen zwischen rechtem Schilddrusenlappen und Sternoklavikulargelenk. Der Verdacht auf ein lokoregionales Rezidiv konnte durch eine 99m-Tc/MIBI-Szintigraphie sowie eine selektive Parathormon-Katheteruntersuchung mit Spitzenspiegeln im Bereich des Zusammenflusses von Vena jugularis interna und Vena subclavia weiter erhartet werden. Die hyperkalzamische Krise konnte durch Infusionstherapie, Furosemid- und Pamidronat-Gabe klinisch und laborchemisch gunstig beeinflust werden, so das bei normalem Bewustseinszustand am dritten Tag des stationaren Aufenthaltes eine En-Bloc-Resektion des Rezidiv-Tumors mit Entfernung zervikaler und mediastinaler Lymphknoten durchgefuhrt werden konnte. Die Patientin konnte mit normalen Kalzium- und Parathormonspiegeln im Serum entlassen werden und ist nach nunmehr 12 Monaten postoperativen Verlaufs ohne Hinweis auf ein neuerliches Rezidiv. Als Komplikation verblieben eine rechtsseitige Recurrensparese und Horner-Symptomatik.

The immunohistochemical expression of somatostatin receptor (SSTR) subtype 2 was compared to quantitative (68)Ga-DOTATATE PET in neuroendocrine tumors (NET).In 27 patients suffering from metastatic NET the expression of somatostatin receptors (SSTR, score 0-3) and the Ki-67 index were assessed. The immunohistochemical findings were compared with the (68)Ga-DOTATATE PET uptake in these tumors using the SUV(max) (standardized uptake value). Both values were compared with the Ki-67 proliferation index.The SUV(max) in NET without SSTR expression was significantly lower compared to those with SSTR expression (p0.05), even though 3 out of 5 NETs with a score of 0 showed a high uptake of (68)Ga-DOTATATE. The SUV(max) correlated significantly (r=0.40, p0.05) with the score of immunohistochemical SSTR expression (negative, score 0, moderate, score 1 and high, scores 2 and 3). The Ki-67 index correlated inversely with the SSTR expression score (r=-0.42, p0.05), but not significantly with the SUV(max) (r=-0.33, p=0.11).(68)Ga-DOTATATE uptake was moderately correlated with the results of immunohistochemical SSTR analyses. However, SSTR negative NET may show high uptake of (68)Ga-DOTATATE.

To evaluate the influence of the introduction of combined PET/CT scanners into clinical routine. This investigation addresses the quantitative changes between PET/CT and stand alone PET.The study included all examinations performed on stand alone PET- or PET/CT-scanners within 12 month prior to and after implementation of PET/CT. The final data analysis included five university hospitals and a total number of 15 497 exams. We distinguished exams on stand alone tomographs prior to and after installation of the combined device as well as PET/CT scans particularly with regard to disease entities. Various further parameters were investigated.The overall number of PET scans (PET and PET/CT) rose by 146% while the number of scans performed on stand alone scanners declined by 22%. Only one site registered an increase in stand alone PET. The number of exams for staging in oncology increased by 196% while that of cardiac scans decreased by 35% and the number of scans in neurology rose by 47%. The use of scans for radiotherapy planning increased to 7% of all PET/CT studies. The increase of procedures for so-called classic PET oncology indications was moderate compared to the more common tumors. An even greater increase was observed in some rare entities.The introduction of PET/CT led to more than a doubling of overall PET procedures with a main focus on oncology. Some of the observed changes in scanning frequency may be caused by a rising availability of new radiotracers and advancements of competing imaging methods. Nevertheless the evident increase in the use of PET/CT for the most common tumour types demonstrates its expanding role in cancer staging. The combination of molecular and morphologic imaging has not only found its place but is still gaining greater importance with new developments in technology and radiochemistry.

Besides the use of conventional x-rays in the diagnostic work-up of initial changes in patients suffering from rheumatoid arthritis (RA), 3-phase bone scintigraphy (3P-Sz) is as well established as magnetic resonance imaging (MRI). The aim of this study was to compare the diagnostic value of ultrasound of the hands with proven methods such as conventional x-rays, low-field MRI and 3P-Sz.A total of 30 patients were studied using a 1 day protocol with ultrasound, 3P-Sz, MRI and x-ray of the hands. Images were visually assessed by two blinded nuclear medicine physicians and radiologists and classified as RA typical and non-RA typical changes. All methods were compared to the summarized findings interpreted by a rheumatologist after 2 years.Of the 30 patients, 19 presented with clinical symptoms of initial changes due to rheumatoid arthritis. Ultrasound revealed 14/19 patients with the correct diagnosis. Conventional x-rays indicated 11/19 patients, while 3P-Sz (100%) and low-field MRI (95%) showed high sensitivity. It was possible to differentiate between inflammation and inconspicuous findings.An experienced examiner can use ultrasound effectively for the initial diagnosis of RA. Based on its low cost, ultrasound is a valid alternative to conventional x-rays.

With about 4 million diabetics in germany and presumed inclination over the following years the treatment of diabetic complications like diabetic foot will become an even more important point. The management of Charcot's foot has undergone fundamental change in the last few years. Formerly, treatment was almost exclusively limited to non surgical measures; since the late 1990's, however, current practice has shifted to early, stage-appropriate surgical therapy. The aim of the present prospective study was to investigate the value of positron emission tomography (PET) in the pre-operative work-up of Charcot's foot. PET were compared to magnetic resonance tomography (MRI).MRI and PET imaging were used as part of the preoperative work-up in 18 patients with Type II diabetes mellitus. The diagnosis of Charcot's foot requiring surgical treatment were made on the basis of clinical and radiologic criteria.Of 46 Charcot's lesions confirmed at surgery, 44 and 35 were detected by means of PET and MRI, respectively. PET can be used in the work-up of patients with metal implants where the MRI does not show adequate findings. PET shows the areas of detritus formation exhibit only moderately increased glucose metabolism and at visual interpretation do not usually impression as typical for acute osteomyelitis. Average SUV values stood at 1.2 (range: 0.5-2.9).The differentiation between Charcot's lesions and florid osteomyelitis provides the surgeon with important additional information, which is often unavailable from MRI. Because of this important additional data, PET could be considered preferable to morphologic imaging (CT, projection radiography) in the preoperative work-up of Charcot's foot.

Besides conventional x-ray, in the diagnostic work up of initial changes in patients suffering from rheumatoid arthritis (RA), 3-phase bone scintigraphy (3P-Sz) is as well established as magnetic resonance imaging (MRI). The AIM of this study was to compare the diagnostic value of a newly developed low field MRI with proven methods such as conventional x-ray and 3P-Sz.42 patients were studied using a one days protocol with 3P-Sz, MRI, and x-ray of the hands with yearly follow up examinations. Images were visually assessed by two blinded nuclear medicine physicians and radiologists and classified as RA-typical and non-RA-typical changes. All methods were compared to the summarised findings interpreted by a rheumatologist in consideration of the Ritchie articular index as gold-standard.24/42 patients presented with clinical symptoms of initial changes by rheumatoid arthritis. Conventional x-ray revealed in 20/24 patients within the correct diagnosis in the study period. On the other hand 3P-Sz and low field MRI concordantly showed all 24 patients with initial changes due to RA. Time of detection showed variations with a tendency to later findings by conventional x-ray.In the diagnostic work up of initial changes conventional x-ray should be the first choice in imaging. Our findings suggest that MRI represents an equally sensitive method for the diagnosis of initial changes due to RA in the region of the hands as compared to the 3P-Sz. The limitation of the low field MRI is the small field of view, so we prefer 3P-Sz or high field MRI in the diagnosis of patients with suspected RA.

To compare the accuracy in the detection and staging of various malignant tumors with high resolution whole-body MRI using parallel imaging with whole-body dual-modality PET-CT.Preliminary results of an interim analysis from a prospective, blinded study are presented, in which 20 patients (mean age 59 years, range 27-77 years) with different oncological diseases underwent whole-body dual modality FDG-PET-CT screening for tumor search or staging in case of confirmed or suspected metastatic disease. All patients also underwent whole-body MRI imaging with the use of parallel imaging (iPAT). High-resolution coronal T1w- and STIR-sequences of 5 body levels with 512 x 512 matrix, axial fast T2w imaging of lung and abdomen (HASTE), contrast-enhanced dynamic and static T1w-sequences of liver, brain, abdomen, and pelvis were performed. Using a 32-channel whole-body MRI scanner (Magnetom Avanto, Siemens Medical Solutions) with a total field of view of 205 cm and free table movement, all patients could be covered from head to toe within one examination. With this technique, high spatial resolution and acceptable scanning times could be obtained. Two experienced radiologists read the MRI-scans, one radiologist and one nuclear scientist read PET-CT scans, each in consensus in a clinical setting. Delineation of the primary tumor (T-stage) or recurrent tumor, pathologic lymph node involvement, as well as degree and localization of metastatic disease, was assessed using PET-CT as standard of reference.Metastases from gastrointestinal tumor (25%) and breast cancer (25%), genitourinary tumor (15%) and malignant melanoma (15%) were detected. In 4/20 patients the primary tumor was identified, 2/20 patients showed recurrent tumor. Of 140 malignant lesions detected by PET-CT, 124 lesions were detected with MRI, resulting in a sensitivity of 89% at a specificity of 86%. In malignant lymph node detection, sensitivity of MRI was 83% and specificity 85%.Whole-body MRI is a promising technique in the detection of primary tumor and metastatic disease. Sensitivity in the assessment of lymph node metastases seems to be limited. With the use of parallel imaging (iPAT), dedicated high-resolution whole-body MRI is possible within acceptable scanning times.

Until now scintimammography did not achieve any definite role in the assessment of breast lesions. Purpose of this study was to elaborate its use as well as the limitations of scintimammography after 500 examinations completed.Scintigraphic findings were correlated with the histopathologic outcome of 219 patients, who underwent surgery or biopsy for histopathological confirmation. The results were determined with respect to palpability of the lesion and tumour size. Additionally, a distinct analysis was performed for the patient subpopulation with indeterminate results of previously performed physical examination, mammography, and sonography.Overall sensitivity for scintimammography was 82.1% at a specificity of 87.5%. For palpable lesions sensitivity was 91.7% which was evidently higher as compared to 64.9% for non palpable lesions. For palpable lesions specificity was 81.1% and 88.6% for non palpable lesions. According to tumour size sensitivity ranged between 65.2% for carcinoma with a diameter1 cm and 93.7% for carcinoma1 cm. In the patients subgroup with indeterminate preliminary diagnosis (n = 143) sensitivity decreased to 71.7% at a specificity of 87.8%. Patients undergoing neoadjuvant chemotherapy showed decreasing sestamibi uptake as early as 8 days after therapy if tumour response was evident. However, small residual invasive tumours in patients with complete remission could not be visualised.Scintimammography is neither suited for screening, nor early diagnosis of breast cancer, nor for the further evaluation of small and unclear mammographic findings. Scintimammography should not be used whenever histopathological clarification of a suspicious lesion is necessary. It is useful to further investigate patients with unclear or probably benign findings in physical examination and/or mammography and to monitor tumour response to neoadjuvant chemotherapy.

Correct staging of head and neck cancer is important for the patient's prognosis and further therapeutic strategies. Aim of the present study was to investigate the diagnostic value of FDG-PET regarding the pre-surgical diagnosis of primary tumor and cervical lymph node metastases, the diagnosis of tumour recurrence, and the localisation of unknown primary, further to compare the results to those of morphological imaging modalities (CT/MRI) and to correlate the results of both methods with histopathological findings.115 patients (pts) (72 x primary diagnosis, 37 x recurrence, and 6 x unknown primary) underwent FDG-PET (ECAT EXACT HR+) and CT or MRI. Results were correlated with histopathological findings in terms of detection of primary and recurrent tumors as well as lymph node metastases.Regarding the pre-surgical diagnosis, sensitivity and specificity for identifying primary tumors were 85 % and 100 % for PET and 88 % and 75 % for CT/MRI, respectively. Accuracy was 86 % for PET and 87 % for CT/MRI. Sensitivity and specificity for detecting primary lymph node involvement were 71 %/86 % for PET and 74 %/57 % for CT/MRI, resulting in an accuracy of 77 % with PET and 68 % with morphological imaging. In 23 pts histopathology revealed pT1 stages with tumor diameters12 mm. In 8 pts CT/MRI and in 10 pts PET failed to identify these small primary lesions. Detecting tumor recurrence (n = 37) PET showed a higher sensitivity (83 %), specificity (76 %) and accuracy (78 %) compared to CT/MRI (sensitivity: 67 %; specificity: 52 %; accuracy: 57 %). In 4/6 pts with unknown primary, imaging was able to identify a primary lesion (3/4 in FDG-PET, 2/4 in CT/MRI), in 2/6 patients even in the follow-up no primary tumor was found.FDG-PET provides only minor additional information to morphological imaging concerning diagnosis of primary tumors. At a similar level of sensitivity, however, it seems to be more specific regarding the lymph node involvement. PET seems to be superior to CT/MRI in detecting tumor recurrence as well as occult primary tumors in pts with known cervical lymph node metastases.

The objective of this prospective study was to determine the extent to which the levels of thyroid-stimulating hormone (TSH) influence the uptake of FDG by thyroid carcinoma tumorsTen patients with follicular (n = 7) or papillary (n = 3) thyroid carcinoma underwent FDG PET during TSH suppression (0.05 microU/mL) and TSH stimulation (22 microU/mL) within an average interval of 42 d (range, 28-73 d). The findings were evaluated by visual criteria. In addition, a tumor-to-background ratio (TBR) was determined for 17 lesions that were visualized.In 15 of 17 lesions with positive FDG uptake, TSH stimulation was associated with an increase in the TBR from 3.85 +/- 2.53 (mean +/- SD) to 5.84 +/- 4.84, corresponding to an average increase of 63.1% (P0.001). Determination of absolute counting rates indicated that this increase was the result of a decrease in FDG metabolism in the background together with an increase in the tumor tissue. No relationship was found between the presence or absence of iodine storage capacity (5 versus 12/17 lesions) and increase in FDG accumulation. Seven of 10 patients had additional iodine-positive metastases that showed no accumulation of FDG.Most locally recurrent and metastatic follicular and papillary thyroid carcinomas exhibited a significant increase in FDG uptake on TSH stimulation. In 3 of 10 patients, TSH stimulation resulted in either detection of new lesions or classification of the FDG uptake pattern as typical for malignancy. These findings suggest that FDG uptake in recurrent and metastatic thyroid carcinoma depends on the TSH level. Therefore, we recommend that PET examinations be performed in patients with thyroid carcinoma under TSH stimulation and follow-up examinations be performed under identical TSH conditions to prevent erroneous interpretation.

MRI plays an important role in the diagnostic workup of skeletal metastases. In principle two different applications of MRI can be distinguished: apart from the well known indications of clarifying uncertain lesions seen with other imaging modalities or demonstrating known osseous lesions with high resolution imaging for therapeutic planing, MRI can also be used as a primary screening modality for skeletal metastases. Besides the higher lesion detection rate the major advantage of MRI compared to bone scintigraphy lies in the demonstration of morphology which on the one hand exactly shows the extension of tumorous lesions and on the other hand clearly distinguishes between malign and benign processes. As unclear findings on bone scintigraphy often require additional imaging studies, especially in patients with clinical findings or lab results suggestive for metastatic disease, we think that whole-body-skeletal-MRI is not only an accurate but also a cost effective diagnostic modality in the detection and screening for skeletal metastases, if the indication for the examination is closely related to clinical findings and the therapeutic relevance of the imaging results.

To evaluate the potential of MRI in determining benign and premalignant abdominal tumors in childhood.MR images of 93 children with 69 malignant and 24 benign abdominal tumors were analyzed retrospectively without and with knowledge of clinical findings. Based on the final diagnosis, MR findings were surveyed with regard to the correct differential diagnosis and to the differentiation between benign and malignant masses.Analysis of MRI alone revealed relatively low sensitivity of 67% for diagnosis of a benign tumor. The main reason was unspecific morphologic criteria leading to the false-negative diagnosis of a malignant tumor. Together with clinical and laboratory findings, sensitivity could be increased to 92%. The main criterion for differentiation of malignant tumors turned to be out the origin of tumor. Benign tumors could be best differentiated by their internal structure.When considering clinical findings in pediatric abdominal tumors, MRI represents a valuable modality for differential diagnosis.

The purpose of our study was to compare the results of planar and SPECT scintimammography for the detection of breast carcinoma. In addition, our goal was to determine whether SPECT reconstructed with filtered backprojection (FBP) or with iterative algorithms (ISA) can improve the sensitivity and specificity of planar scintimammography (SMM).One hundred thirteen patients with suspicious physical examinations and/or mammography underwent planar lateral and anterior breast imaging as well as SPECT imaging after injection of 99mTc-sestamibi. We used a blind evaluation, both separately and combined, for planar SMM, ISA-SPECT and FBP-SPECT. Scintigraphic findings were correlated with the final histopathological diagnoses.The sensitivity of planar SMM was 80% with a specificity of 83%. All ISA-SPECT studies were of diagnostic quality, while FBP-SPECT was considered nondiagnostic in 14 that were excluded for statistical calculation. Sensitivity of ISA-SPECT and FBP-SPECT were 71% and 69%, respectively. Specificity was 70% for ISA-SPECT and 66% for FBP-SPECT. Combined planar SMM plus ISA-SPECT sensitivity was 85% (81% for planar SMM plus FBP-SPECT) with a specificity of 72%. Three carcinomas indeterminate on planar SMM were correctly identified by combined planar SMM plus ISA-SPECT. ISA-SPECT and FBP-SPECT provided additional information to planar SMM with respect to localization of sestamibi uptake, tumor extent, improved diagnostic certainty and detection of axillary nodes in 40 and 14 patients, respectively.ISA reconstruction is the preferable approach to SPECT data. Combined with planar SMM, ISA-SPECT can improve sensitivity. SPECT is useful in cases of indeterminate and positive planar SMM.

In den vorausgegangenen Kapiteln wurden — sicherlich ohne ausnahmslos alle verfugbaren Methoden abgehandelt zu haben — die wichtigsten bei der Diagnostik des Mammakarzinoms eingesetzten bildgebenden Verfahren besprochen.

Purpose of this study was to assess the clinical value of sestamibi whole body scintigraphy in detecting local recurrences and metastases in patients with differentiated thyroid carcinoma and to compare these results with diagnostic 131-radioiodine scans and serum thyroglobulin determinations. 75 patients — following all total thyroidectomy and high dosed radioiodine therapy — underwent sestamibi and diagnostic iodine scintigraphy. In addition, serum thyroglobulin levels were determined. Only patients with elevated thyroglobulin levels showed positive sestamibi and/or iodine uptake. In comparison with iodine scans sestamibi scintigraphy revealed with a higher sensitivity recurrences and metastases especially in follicular and Htirthle cell carcinoma.

Scintimammography using Tc-99m sestamibi and contrast enhanced MRI were performed in order to determine the accuracy of both methods in the diagnostic work up of patients with suspicious or indeterminate preliminary diagnosis. 25 controls and 56 patients (14 with suspicious and 42 with indeterminate preliminary diagnoses), in whom physical examination and/or mammography warranted breast biopsy, underwent prone planar scintimammography. Sestamibi uptake was scored visually and measured using the ROI technique to enable semiquantitative evaluation. The patient group additionally underwent plain and contrast enhanced MRI. Visually determined signal increase following application of Gd-DTPA was compared with scintigraphic findings and final histopathologic results. Sensitivity and specificity of semiquantitative scintimammography for diagnosing breast cancer was 88% and 87%, respectively. Based on ROC analysis a target/non target ratio R1.3 was shown to be the optimal threshold for separating benign from suspicious scintigraphic diagnoses. MRI reading provided a slightly higher sensitivity (91%), but a considerable lower specificity (52%) due to contrast enhancement of different benign lesions. In the clinically important patient subpopulation with indeterminate results from previous diagnostic procedures, sensitivity of scintimammography fell to 79%, while specificity remained at 87%. MRI revealed a higher sensitivity of 89% and a lower specificity of 52%. Our data indicate that semiquantitative scintimammography using Tc-99m sestamibi provides a comparable sensitivity to contrast enhanced MRI in the assessment of breast cancer. The latter does not reduce the number of biopsies yielding benign results due to the high number of false positive diagnoses. Therefore, scintimammography seems to be the preferable tool in the diagnostic work-up of patients with indeterminate mammographic diagnoses.

Scintimammography using 99mTc-sestamibi and contrast-enhanced MRI were performed to determine the diagnostic accuracy of either method in the diagnostic workup of patients suspicious for breast tumors.Fifty-six patients (42 with indeterminate mammograms) underwent preoperative prone planar scintimammography and pre- and postcontrast-enhanced MRI. Visually determined signal increase after application of Gd-DTPA was compared with visually scored sestamibi uptake, and the diagnoses of both methods were correlated with the final histopathologic results.Overall, sensitivity and specificity of scintimammography for diagnosing breast cancer were 88% and 83%, respectively. In the subgroup of patients with indeterminate mammograms, sensitivity was 79% and specificity was 83%. MRI readings provided a higher sensitivity (91% with respect to all patients and 89% with respect to patients with indeterminate mammograms), but a considerably lower specificity (52% in both groups) due to contrast-enhancement in different benign lesions.Due to its considerably higher specificity, scintimammography rather than MRI may be suitable to reduce the number of breast biopsies which yield benign results. Thus, this method may be suggested as the preferable tool in the diagnostic workup of patients with indeterminate mammographic findings.

Although echocardiography is mostly applied for the diagnosis of heart tumors there are restrictions concerning the representation of the mediastinal and cardial topography in spite of the usage of transoesophageal echocardiography. Computed tomography (CT) and magnetic resonance imaging (MR) are able to give a full representation of the heart and also the thorax with mediastinum, pleura, and lungs. Not only for the diagnosis of various kinds of heart tumors but also for decisions concerning the therapy, the detection of postoperative complications and development are CT and MR very valuable procedures. The ability to deliver a complete cross-section of all cardial, mediastinal, pulmonal and thoracic structures--in contrast to angiocardiography--and without any anatomic restrictions in contrast to echocardiography--is another advantage of CT and MR. Because of the fullness of information CT and MR supply these procedures are especially used for the detailed planning of operative procedures. They are also a big help in determining whether surgery might have to be excluded because a complete tumor resection is not possible anymore.

Studies designed to optimise image contrasts of gradient echo sequences showed, that especially repetition times between 250 and 500 ms in combination with adequate echo times and flip angles provide new image contrasts. The clinical purpose of gradient echo sequences with longer TR was systematically evaluated in 450 patients. A major advantage of GE sequences was the low signal intensity of fat and bone tissue. On the other hand different pathologic changes showed a high signal intensity in comparison to T2 weighted spin echo sequences as well. With the possibility of multiple slices GE sequences were of outstanding diagnostic value especially in MR of soft tissue and of the musculoskeletal system. T2 weighted SE sequences provided no additional informations and could therefore be omitted in a great number of examinations.

One hundred temporo-mandibular joints were examined with a super-conducting nuclear resonance tomograph (1.0 Tesla) using various high resolution surface coils. The optimal method proved to be a spin echo sequence with a repetition time of 1,000 msec and an echo period of 28 msec with a 4 mm slice width. There were significant advantages from the non-invasive MRT diagnosis of the temporo-mandibular joints when compared with CT and with arthrography in recognising abnormal discs, changes in the tissues and for post-operative control.

Hitherto T1-weighted Spin-Echo-Sequences, most combined with T2-weighted sequences, were used to detect pathological bone marrow lesions. This method needs a long examination time and results in T2-images with a low morphological resolution. In the majority of examinations using Gradient-Echo-Sequences with prolonged repetition-times (FLASH: flip angle 40 degrees, TR/TE = 500/17 msec) there is no need of an additional measurement. Therefore these sequences save about 75% of the examination time and they give higher contrast between normal and pathological bone marrow.

In a female patient suffering from renal insufficiency in whom angiography could not be performed, it was possible to confirm the diagnosis of a ductus arteriosus (Botallo's duct) by magnetic resonance imaging. The present case report shows that it is possible to visualise this congenital heart disease by MRI. This can be of importance especially if angiography cannot be performed (as in this case) because of renal insufficiency or because of contrast medium allergy.

Bis vor kurzem konnten die intraspinalen Anteile bei Kindern mit spinalen Dysraphien nur mit Hilfe der Myelographie bzw. des Myelo-CT untersucht werden [1]. Bei Sauglingen bis zum Ende des 1. Lebensjahres stellt die Sonographie eine einfache und schnelle Screening-Methode fur intraspinale Veranderungen dar [3]. Die Kernspintomographie (KST) bietet eine multiplanare Abbildung des Rukkenmarks unabhangig vom Alter des Patienten [2]. Die KST ist nichtinvasiv und ohne ionisierende Strahlen. Die Ziele der vorliegenden prospektiven Studie waren: Untersuchung der Einsatzmoglichkeiten der KST als Screening-Methode bei Kindern mit spinalen Dysraphien. Prufung, inwiefern die KST invasivere Methoden (Myelo-CT) ersetzen kann.

Stress fractures can represent a diagnostic problem especially in their differentiation from bone tumours. 6 patients with 7 lesions were examined. MRI visualised the stress fractures and established the diagnosis of stress fracture vs. tumour in 6 cases. In the seventh, biopsy having been performed, a tumour was ruled out. MRI is more sensitive than radiography in the detection of stress fractures, showing the characteristic changes earlier. MRI, being a very sensitive method in the diagnosis of stress fractures and a reliable one in their differentiation from bone tumours, can be applied in cases of unusual clinical course and difficult radiological diagnosis prior to biopsy.

Studies designed to optimise image contrasts of gradient echo sequences showed, that especially repetition times between 250 and 500 ms in combination with adequate echo times and flip angles provide new image contrasts. The clinical purpose of gradient echo sequences with longer TR was systematically evaluated in 450 patients. A major advantage of GE sequences was the low signal intensity of fat and bone tissue. On the other hand different pathologic changes showed a high signal intensity in comparison to T2 weighted spin echo sequences as well. With the possibility of multiple slices GE sequences were of outstanding diagnostic value especially in MR of soft tissue and of the musculoskeletal system. T2 weighted SE sequences provided no additional informations and could therefore be omitted in a great number of examinations.