Search

Tyrosine is a precursor of melanin synthesis and might thus present a valuable marker for melanoma. The aim of this study was to evaluate the uptake of alpha-methyl-tyrosine (AMT) in melanoma cell cultures and to assess its usefulness as a radiopharmaceutical for staging melanoma patients with whole-body scintigraphy. Melanoma (M19-cell lines) and fibroblast (negative control) cell cultures were incubated with 125I-AMT and the radioactive uptake in the cell lines was measured in a gamma-counter over 24 h. For in vivo studies, planar whole-body scintigraphy and single photon emission computed tomography (SPECT) of the tumour region was performed following injection of 250-350 MBq 123I-AMT in six patients with known melanoma metastases. Findings were compared with results of whole-body positron emission tomography using 18F-fluorodeoxyglucose (FDG-PET) as a standard of reference. Fibroblasts showed an unchanged uptake of (mean +/- SD) 0.56 +/- 0.09% 15 min and 0.066 +/- 0.09% 24 h, respectively, after incubation of 125I-AMT, whereas there was an increased uptake in melanoma cell cultures over time from 0.9 +/- 0.05% to 7.5 +/- 1.6%. In staging melanoma patients, the sensitivity of whole-body AMT-scintigraphy compared with FDG-PET was 37% (10 of 27 metastases). AMT is transported and metabolized to a high extent in melanoma cells and 123I-AMT is accumulated in melanoma metastases. Owing to its low sensitivity, however, the clinical use of whole-body AMT scintigraphy cannot be recommended.

Zusammenfassung Ziel: Ziel der Studie war es, die Wertigkeit der Szintigraphie mit L-3-123I-α-Methyltyrosin (123I-AMT) beim metastasierenden Melanom zu untersuchen. Methoden: 26 Metastasen und ein Primärtumor eines malignen Melanoms bei sechs Patienten wurden mit einer 123I-AMT-Ganz-körperszintigraphie und SPECT untersucht. Als Referenzmethode lag eine Positronen-Emissions-Tomographie mit 2-18F-Fluor-2-desoxy-D-gluco-se (18F-FDG) vor. Ergebnisse: Mit 123I-AMT-SPECT ließen sich 8/10 Thoraxmetastasen mit einem Durchmesser >1,6 cm nachweisen (Ratio T/NT 1,2-1,8), Metastasen

Optimal treatment parameters and appropriate methods of examination for Nd:YAG laser coagulation of the human prostate in dependence of power-setting and time using the SideFocus side-firing delivery system have been determined. Transurethral free-beam laser coagulation was performed in 10 patients prior to planned radical prostatectomy or cystoprostatectomy. Thereof, 6 patients underwent transperitoneal laparoscopic lymphadenectomy and laser coagulation of the prostate between 4 and 9 days prior to open surgery. These same patients had undergone MRI examination with an endorectal coil during staging and prior to radical prostatectomy. Depth and volume of coagulated prostatic tissue of a 4-quadrant laser application were measured at power-settings of 40 W/90 s and 60 W/60 s. There was no difference in volume coagulation between the two treatment modalities. In contrast there was a significant difference in volume coagulation between those prostates removed at 4-9 days and those removed at 60-210 min after laser coagulation. In histological and MRI examination, however, there was a strong correlation with view to coagulation volume in histological and MRI examination. Using the SideFocus side-firing laser fiber, both treatment modalities showed comparable volume coagulation. Laser-induced changes are conclusively discernible by 4 days, MRI examination with an endorectal coil thus being perfectly suitable for assessment.

Background: To compare endorectal coil magnetic resonance imaging (MRI) with body coil MRI in detecting local recurrence of gynecologic tumors and prostate and rectal cancers. Methods: Forty-six patients with suspected recurrent pelvic malignancies (13 gynecologic, 15 prostatic, and 18 anorectal primaries) were enrolled in the study. Axial T1- and T2-weighted body coil images and T2- and contrast-enhanced T1-weighted axial endorectal coil images were obtained on a 1.5 T system. Results of the MR examinations were compared with histogical findings and follow-up examinations with respect to the diagnostic accuracy and diagnostic confidence for assessment or exclusion of local recurrence. Results: Recurrent disease was histologically confirmed in eight patients with primary gynecologic malignancies, seven with suspected prostatic recurrence, and seven with suspected anorectal recurrence. Overall, accuracy of body coil MRI was 67% for gynecologic tumors, 36% for prostatic recurrences, and 59% for rectal recurrences. T2- and contrast-enhanced T1-weighted endorectal sequences yielded similar results, with an accuracy of 73% for depiction of gynecologic recurrence, 77% for prostatic recurrence, and 77% for rectal recurrence. The difference in accuracy between body coil and endorectal coil examinations was statistically significant (p < 0.05) only for prostatic cancer. Diagnostic confidence was, however, significantly improved (p < 0.05) in all tumors (T2-weighted endorectal coil examination was superior to T2-weighted body coil images in 71% of cases). Conclusion: Although the results of endorectal coil MRI are only slightly superior to those of body coil MRI for the detection of recurrent gynecologic and anorectal tumors, diagnosis can be made with greater diagnostic confidence in many cases. For detection of prostatic recurrence, endorectal MRI is highly recommended.

(1) To compare scintigraphy using the new dopamine D2 receptor binding radioligand iodobenzofuran (IBF) versus whole-body positron emission tomography (PET) in demonstrating metastasizing melanoma, and (2) to determine, for the first time using a panel of histochemical techniques, whether the ability of D2 receptor binding radioligands to detect melanoma metastases is due to tumor-expressed D2 receptors.Seven patients with metastatic melanoma were examined using 123I-IBF scintigraphy. Findings were compared to the results of PET and metastasis histochemistry: D2 receptor mRNA assay (metastases: n = 5; melanoma cell lines: n = 4) using the reverse transcriptase polymerase chain reaction (RT-PCR) versus D2 receptor-transfected Chinese hamster ovary cell controls: in vitro 125I-IBF binding (n = 19), and immunohistochemical staining for dopamine D2 receptor protein (n = 19).IBF scintigraphy detected 2/10 melanoma metastases detected by PET (sensitivity 20%). No dopamine D2 receptor mRNA was found in melanoma cells using RT-PCR. The binding of 125I-IBF correlated with the amount of melanin present in the metastases; two amelanotic melanomas both failed to bind 125I-IBF. Immunohistochemical staining was negative in all metastases.Melanoma cells do not appear to express dopamine D2 receptors. Although IBF had high dopamine D2 receptor affinity, its ability to detect melanoma metastases is more likely explained by low affinity binding to melanin than by the presence of dopamine receptors.

To evaluate whole-body positron emission tomography (PET) with 2-[fluorine-18]-fluoro-2-deoxy-D-glucose (FDG) in the detection of metastasis from melanoma.Whole-body PET was performed in 33 patients with either known metastatic or newly diagnosed melanoma. Patients with suspected metastases also underwent computed tomography, magnetic resonance imaging, or both. Diagnoses were confirmed with histologic examination or with at least one imaging modality in addition to PET. Blinded interpretations of PET scans were performed.Forty of 53 lesions evaluated proved to be melanoma metastases. Whole-body PET correctly depicted 37 sites of metastases. Three cutaneous metastases (3 mm) were missed. PET correctly excluded malignancy in 10 cases where suspicious lesions were found with conventional cross-sectional imaging modalities but later ruled out with fine-needle biopsy. In six patients, PET depicted new metastases. The sensitivity for the detection of malignant lesions was 92%; the specificity for reading the PET images without clinical information was 77% and with clinical information was 100%.These results suggest that whole-body FDG PET is an effective imaging modality to screen for metastases from malignant melanoma.

Objective Our goal was to evaluate contrast-enhanced MRI using an endorectal coil in detecting and staging prostate carcinoma. Materials and methods Sixty patients with clinically suspected prostate carcinoma were examined by T1-weighted contrast-enhanced endorectal coil MRI at 1.5 T. Results were compared with T2-weighted images in all cases and with histologic findings following radical prostatectomy in 28 patients. Results Prostate carcinomas showed no consistent pattern of contrast enhancement. In 27 patients, the tumor enhanced less than the surrounding prostatic tissue; in 10 patients, enhancement was heterogeneous; and in 23 cases, the lesion was hyperintense compared with normal glandular tissue. With respect to tumor delineation, contrast-enhanced sequences were superior to T2-weighted images in 1 case only; in 24 patients, the tumor could not be delineated at all. However, contrast-enhanced sequences provided a higher diagnostic confidence in delineating the seminal vesicles, prostate capsule, and neurovascular bundle in nine, six, and three cases, respectively. In the operated patients, accuracy, sensitivity, and specificity for staging advanced disease were comparable for both sequences. Conclusion The T2-weighted sequences remain mandatory for delineation of prostate carcinoma. Contrast-enhanced T1-weighted sequences do not improve overall staging accuracy and therefore are not warranted routinely, but should be considered in cases requiring clearer delineation of the prostate capsule and/or seminal vesicles.

ZusammenfassungIn jüngsten Publikationen wurde die Dopamin-D2-Rezeptorszintigraphie mit Benz-amiden zur spezifischen Darstellung von Melanomen vorgeschlagen. In einer prospektiven Studie wurde die Wertigkeit von 123I-Jodbenzofuran (IBF), einem hochspezifischen und hochaffinen Dopamin-D2-Rezeptorliganden zum Nachweis von Melanommetastasen untersucht. Mit der IBF-D2-Rezeptorszintigraphie ließen sich nur 2 von 17 Melanommetastasen nachweisen. Die Beurteilung des Abdomens war durch die hepatobiliäre Ausscheidung des Radionuklids stark eingeschränkt. Der Quotient Striatum/Frontalhirn von 2,75 ± 0,49 3 h p.i. belegte die hohe D2-Rezeptorbindung des Liganden. Die IBF-D2-Rezeptorszintigraphie ist als Staginguntersuchung beim Melanom nicht geeignet.

Ultrasonographic (US), computed tomographic (CT), and magnetic resonance imaging (MRI) findings of a patient suffering from an amebic abscess of the liver complicated by a bronchohepatic fistula are presented. Subsequent to US, CT provided the specific diagnosis. Multiplanar MRI was valuable to directly visualize the secondary diaphragmatic rupture and the bronchohepatic fistula.

The aim of the study was to evaluate the ranking of the scintigraphy with L-3-123I-alpha-methyltyrosine (123I-AMT) in metastasized melanoma.26 metastases and one primary tumor of a malignant melanoma in six patients were examined with 123I-AMT whole-body scintigraphy and SPECT. Positron Emission Tomography with 2-18F-fluoro-2-desoxy-D-glucose (18F-FDG) was used as the golden standard.With 123I-AMT-SPECT 8/10 metastases in the thorax1.6 cm were detected (ratio T/NT 1.2-1.8), metastases1.6 cm were not detectable with SPECT. In 123I-AMT whole-body scintigraphy not one lesion showed a positive tumor uptake.In single cases 123I-AMT scintigraphy can be helpful in staging of malignant melanoma.

Minimally invasive treatments for benign prostatic hyperplasia (BPH) are currently very controversial. Nd:YAG laser transurethral thermocoagulation of the prostate is the technique most frequently used. The objective of this study was to assess the correlation between the morphological effects observed and the changes visible on magnetic resonance imaging during this type or treatment in the human prostate, in order to evaluate the tissue effects obtained according to the power and the interaction time applied. In 10 patients requiring radical prostatectomy for urological cancer, visual laser ablation of the prostate (VLAP) was performed during the 10 days preceding the radical operation (range: 1 to 9 days). The entire gland was submitted to pathological examination in order to correlate the histological result with contrast magnetic resonance imaging performed in 6 patients, using a standard transrectal coil, 12 to 24 hours before complete resection of the prostate. The morphological examination showed zones of periurethral necrosis of variable volume, accompanied by extensive peripheral haemorrhage, containing vessels with a partially obliterated lumen. Contrast magnetic resonance imaging (T1) showed that laser-induced lesions had a low density appearance and were perfectly demarcated with peripheral heterogeneous and hyperdense zones. In contrast with the experimental investigations performed to date, we demonstrated a clearly delayed tissue effect. Our experience demonstrates that a period of several hours between laser treatment and removal of the operative specimen is not sufficient to evaluate the extent of laser-induced lesions. High resolution magnetic resonance imaging with a standard transrectal coil, sometimes combined with a multiple coil, is very valuable to assess the effects of laser.

The purpose of this study was to semiquantitatively identify artifactual and physiological soft-tissue accumulations in whole-body FDG-PET scans with the aim of defining their frequency and anatomic distribution.Fifty whole-body FDG-PET scans performed for the staging of malignant melanoma were obtained from transaxial scans and reconstructed without absorption correction by filtered backprojection in the form of coronal and sagittal sections. The patients were asked to stay n.p.o. for at least 4 hr and interrogated about their physical activity prior to injection and until scanning. Classification of FDG organ accumulations was done using grades 0-6. Means and standard deviations on this scale were then calculated for multiple organs and muscle groups and tabulated.On this grading scale, viscera showed uptake grades between 1.7 +/- 0.5 and 2.05 +/- 1.0. Except for the intestines, the activity in these organs was homogeneously distributed. Relatively high average uptake values of 2.0-4.2 (s.d.or = 2.3) were found in various muscle groups, especially the orbital musculature. Myocardial uptake was visible in 90% of the scans. Reconstruction artifacts were seen around the renal collecting system and the bladder.Most of the "normal" accumulations of FDG in nonattenuation corrected whole-body PET are readily recognized and distinct from the usually focal FDG accumulation associated with metastatic disease, but the diagnostician must be familiar with them. Muscular FDG uptake is related to physical activity prior and immediately following injection and can be minimized by proper patient instructions and positioning.

Technical developments including motion artifact compensation and the use of paramagnetic contrast agents have substantially improved the performance of MR imaging of the kidneys and adrenal glands. MR imaging allows one to assess morphologic alterations of the kidneys as well as perfusion and functional derangements. MR imaging is the best noninvasive method for distinction of benign from malignant adrenal masses.

Pathologic alterations of the kidneys include not only morphologic changes, but also functional disorders. Some diseases such as glomerular and tubulointerstitial disorders or vascular insufficiency can even lead to substantial dysfunction without visibly alterated morphology. Renal angiography as well as radionuclide renography can be employed for the study of perfusion and excretory function of the kidneys. MRI, however, has the advantage to provide both information on morphology and on renal function.

Purpose: The diagnostic value of endorectal coil MRI, body coil MRI, transrectal ultrasound, digital rectal examination and PSA levels were prospectively analysed in order to define the most accurate preoperative staging method. Methods: 33 patients with prostate carcinoma, who underwent subsequent prostatectomy, were enrolled in the study and examined on a 1.5 T system using the body coil as well as the endorectal surface coil before and after the administration of contrast material. The results were compared to digital rectal examination, prostate specific antigen levels and endorectal ultrasound. Results: Staging accuracy of endorectal coil MRI was 87.9% with a sensitivity of 88.9% and specificity of 86.7%. For body coil MRI, the staging accuracy was 75.7%, the sensitivity 66.7% and the specificity 87.9%, for transrectal ultrasound 69.6%, 41.7% and 100% and for the digital rectal examination 56.6%, 33.3% and 100%, respectively. Prediction was improved by combining results of endorectal coil MRI with PSA values. Conclusion: Endorectal ultrasound and digital rectal examination both had a tendency to underestimate the extent of the lesion. Endorectal coil MRI proved to be the best preoperative staging method. In combination with PSA values, diagnostic accuracy could be further improved. Therefore, local staging of prostate cancer could be based on these two parameters alone.

In recent publications dopamine-D2 receptor scintigraphy with benzamides was postulated for specific imaging of melanoma. In a prospective study the value of 123I-iodobenzofuran (IBF), a highly specific and affine dopamine-D2 receptor ligand was evaluated for the detection of melanoma metastases. With IBF-D2 receptor scintigraphy only 2 of 17 melanoma metastases could be detected. The interpretation of the abdomen was impaired by the hepatobiliary and renal excretion of the radionuclide. The ratio striatum/frontal cortex of 2.75 +/- 0.49 3 h p.i. demonstrated a high D2-receptor binding of the ligand. IBF-D2-receptor scintigraphy is not suitable as a method of staging melanoma.

Maligne Zellen haben eine erhohte Glykolyserate im Vergleich zu gesunden Gewebe. Die Positronenemissionstomographie (PET) mit dem Glucosanalogon (i8F)FDG wird deshalb erfolgreich zur Darstellung von Tumoren verwendet. Die Ganzkorper-PET ermoglicht es erstmals, diese Methode auch zur Metastasensuche einzusetzen. Das Ziel unserer Studie war es, die Wertigkeit der Ganzkorper-PET beim „Staging“ des malignen Melanoms zu untersuchen. 15 Patienten (Durchschnittsalter 54,8 Jahre) mit Verdacht auf Melanommetasen wurden mit der PET untersucht.

Inflammatory disease of the female pelvis can be diagnosed both on the basis of clinical symptoms and complementary ultrasound. The role of CT and MRI is limited to complicated cases. CT guidance allows the biopsy needle to be localized precisely for diagnostic or therapeutic punctures. Furthermore, CT and MRI play an important role in the evaluation of prolonged puerperal fever of unknown origin: endomyometritis is associated with characteristic features in MRI, whereas puerperal ovarian vein thrombosis is best diagnosed using MR angiography. For other rare causes, MRI and CT have to be used according to clinical need.

Background and Study Aims : Endoscopic ultrasound has become the best available method for local staging of primary rectal cancer and diagnosing recurrent local disease. The aim of this study is to compare the value of endoscopic ultrasound (EUS) to magnetic resonance imaging with an endorectal coil (EMRI). Patients and Methods : Twenty-one patients (11 women, 10 men, mean age 63 years, range 31-79) with primary rectal cancer (n = 6) or follow-up examinations for recurrent local disease (n = 15) were investigated by EUS using an echo colonoscope (CF-UM 20, Olympus Optical) and by endorectal coil MRI on a 1.5 tesla MR system (General Electric). T 2 -weighted and contrast-enhanced T 1 -weighted images were obtained. The results of preoperative examinations were compared to histopathological findings regarding the T staging, with special focus on the transmural tumor infiltration. Results : EUS identified all tumors, whereas one tumor was missed by EMRI. EUS was superior to EMRI in T staging (accuracy 83%/40%), due to the better differentiation between T1 and T2 tumors, as the endorectal coil could not differentiate between stage T1 and stage T2. The accuracy of EMRI in assessing perirectal infiltration was 80%, compared to EUS with 100%. Local tumor recurrence was found in six of 15 patients, without endoscopic signs of recurrent disease in four of them. All were detected by EUS. Only one recurrence was missed by EMRI. Accuracy and positive and negative predictive values in follow-up examinations for recurrent disease for EUS were 93%, 86%, and 100%, and for both the T 2 -weighted and T 1 -weighted contrast-enhanced sequences of endorectal coil MRI, they were 93%, 100%, and 90%, respectively. Conclusions : Endoscopic ultrasound and endorectal coil MRI are comparable methods in the preoperative staging and early diagnosis of recurrent rectal cancer. The advantages of EUS are the small diameter of the instrument, availability, and lower costs. In contrast, EMRI is operator-independent, and may become important for combined local and distant staging and follow-up examination in rectal cancer, if contrast-enhanced imaging can improve the sensitivity for liver metastases.