Quantitative Estimation of I-123-Iomazenil Receptor Binding in Temporal Lobe Epilepsies Using Two SPECT Acquisitions – Comparison with the Regional Cerebral Blood Flow and a Compartment Model

Aim: To compare published fractional rate constants of I-123-lomazenil (IMZ) and C-11-Flumazenil (three-compartment/four-parameter model) with a I-123-lomazenil receptor index calculated from two SPECT acquisitions and to compare the receptor index of the epileptogenic area with the contralateral side in patients with unilateral temporal lobe epilepsies. Methods: 28 patients were studied. 13/28 patients had a drug-resistant unilateral temporal lobe epilepsy with a successful focus localisation performed by an extensive video/EEG monitoring. 15 other patients with clinically suspected focal epilepsy and a normal MRI and IMZ SPECT scanning were used as controls. SPECT scanning was performed in all patients 15 and 100 min after intravenous injection of 111 MBq IMZ and 10 min after application of 740 MBq Tc-99m-HMPAO. Quantification of the regional uptake was performed using ROI-technique and the specific and non-specific binding of IMZ was calculated. The receptor index was calculated by the difference of the specific binding from 15 to 100 min p. i. divided by the time interval. Results: The receptor index showed a linear correlation with recently published fractional rate constants k 3 (r = 0.69 and 0.67; p = 0.15) and a moderate correlation with the k 4 constant (-0.53 and -0.43; p = 0.28) by the means of C-11 -Flumazenil PET and 1-123-lomazenil SPECT studies, respectively. However, statistical significance was not reached due to the few data points available from the published reports. Furthermore, the IMZ receptor index was lower in the epileptogenic area of patients with unilateral temporal lobe epilepsies compared with their contralateral side (p = 0.02; Wilcoxon-test). The IMZ receptor index showed a weak correlation with the regional cerebral blood flow independent of the evaluated region (r <0.4; p <0.05). Conclusion: The IMZ receptor index indicated to be a simple routine approach to estimate the fractional rate constant k 3 (r = 0.67). The lower value of the receptor index within the epileptogenic area might be due to a lower receptor density. However in further studies, IMZ might be a helpful tool to find out subtle changes of the receptor affinity due to its approximately 30-fold higher ligand-receptor affinity compared to C-11-Flumazenil.

[Establishing a protein signature from prostate tissue biopsies]

The prostate-specific antigen test (PSA) has been a major factor contributing to a better management of prostate cancer. The low specificity limits its use in diagnosis especially in early detection of prostate cancer. Multiply expressed proteins need to be identified to establish a disease-specific protein signature that distinguishes between cancerous and noncancerous tissue. The first aim of our study is to identify differentially expressed proteins in both tissues using two-dimensional gel electrophoresis and subsequent mass spectrometry. We elucidated whether prostate biopsies are useful. First results have shown a different protein expression pattern in cancerous and noncancerous tissue. PCR revealed an increasing amount of mRNA for some upregulated proteins. We conclude that biopsies are useful material to establish protein expression patterns.

Global proteome analysis of germ cell tumor (GCT) cell lines under treatment with cisplatin (CDDP)

15567

Background: GCTs are the most common malignancy in young Caucasian males aged 20–40. With CDDP-based chemotherapy, highly effective treatment has been developed for the majority of patients with GCT. However, the molecular mechanisms underlying treatment response remain elusive. Therefore, we used a global proteomics approach to screen for changes induced in GCT cell lines by CDDP. Material and Methods: Global protein expression analysis of three GCT cell lines, NTERA2, 2102EP, and NCCIT, both untreated and treated with CDDP for 48 hours at the IC50, was performed using 2-dimensional gel electrophoresis. Differentially expressed proteins were analyzed using matrix-assisted laser desorption/ionization - time of flight (MALDI TOF) and Fourier transform ion cyclotron resonance (FTICR) mass spectrometry. Identification of proteins was performed using peptide mass-fingerprinting and NCBI/SwissProt and The Global Proteome Machine database search. Results: In total, 66 proteins were found to be differentially expressed comparing untreated and treated cells. Numbers of proteins showing upregulation under CDDP were 18 in NTERA2, 10 in NCCIT, and 9 in 2102EP, whereas 17 proteins were downregulated in NTERA2, 5 in NCCIT, and 7 in 2102EP. Identification of corresponding proteins was successful in 44 out of 66 spots (67%). Differential expression of 5 proteins was found in more than one cell line. One protein (Enolase 1) was consistently up-regulated in all three cell lines under CDDP. The identified proteins can be grouped into different categories: 15 are involved in DNA-binding/transcription, 8 in metabolism, 8 in protein folding/binding/chaperone, 6 in cell signaling/differentiation, 4 in apoptosis, and 3 in cytoskeleton/cell movement. Conclusion: The results of this screening approach identify factors differentially regulated during response to CDDP in GCTs, and reveal a specific response pattern for each cell line. This knowledge can help to identify therapeutic targets and factors potentially involved in treatment sensitivity and resistance.

No significant financial relationships to disclose.

Expression of annexin AI in conventional renal cell carcinoma (CRCC) correlates with tumour stage, Fuhrman grade, amount of eosinophilic cells and clinical outcome

There is increasing evidence that Annexin AI (ANX AI) expression is dysregulated in several carcinomas and tumour cell lines. In order to gain insight into the putative role of ANX AI in tumorigenesis, clinical outcome and metastatic potential of conventional renal cell carcinomas (CRCCs) we investigated the expression of ANX AI in CRCCs and metastases. Furthermore, it was elucidated whether ANX AI overexpression affects migratory potential in Caki-1 cells. ANX AI immunohistochemistry was performed on 33 samples of CRCCs and 10 metastases. ANX AI expression was assessed in 12 samples by 2-dimensional gelelectrophoresis (2-DE), subsequent mass spectrometry and RT-PCR. Immunohistochemical data were statistically correlated with pathological parameters, amount of eosinophilic cells and clinical outcome. Furthermore, a haptotactic migration assay was done on Caki-1 cells transfected with ANX AI. Immunostaining for ANX AI was found in 18 tumours and all metastases investigated. Intensity of immunohistochemical staining correlated to Fuhrman grade, amount of eosinophilic cells and clinical outcome. 2-DE and RT-PCR confirmed the presence of ANX AI in neoplastic tissue. Overexpression of ANX AI did not significantly influence cell migration. From these findings ANX AI expression seems to be related to Fuhrman grade, clinical outcome and metastatic potential of CRCCs. Thus ANX AI could serve as a prognostic marker for tumour progression.

[Percutaneous vertebroplasty -- the role of osseous phlebography]

PURPOSE

To evaluate the usefulness of osseous phlebography preceding percutaneous vertebroplasty.

MATERIALS AND METHODS

Seventy-five patients with painful osteoporotic (57) or malignant (18) vertebral fractures were treated by percutaneous vertebroplasty under fluoroscopic control. Prior to cement injection, osseous phlebography was performed, with 247 phlebographic studies included in the retrospective correlation with radiographic and CT images. Clinical results were assessed by standardized questionnaire.

RESULTS

In 69/75 (92 %) patients, pain and mobility improved and medication needed for pain control decreased significantly after vertebroplasty. Two clinically apparent complications occurred. The results of osseous phlebography prompted correction of the needle position in 34/247 (14 %) of the procedures and cancellation of the cement injection in 19/247 (8 %). No complications occurred related to osseous phlebography. CT was superior to conventional radiography in detecting extra-osseous cement leakage (106/247 by CT vs. 63/247 by conventional radiography). The cement leakage was asymptomatic in 104/106 (98 %) cases for the duration of follow-up.

DISCUSSION

Osseous phlebography prior to percutaneous vertebroplasty had a significant impact on the procedure in our retrospective study and was able to predict the cement distribution in the majority of cases. However, phlebography was unable to foresee and therefore prevent 2 clinically relevant complications. Complications related to phlebography did not occur.

Combined 123I-FP-CIT and 123I-IBZM SPECT for the diagnosis of parkinsonian syndromes: study on 72 patients

72 consecutive patients with suspected parkinsonian syndromes (PS) were studied by dopamine transporter (DAT) and D2 receptor SPECT in order to evaluate the accuracy of combined SPECT imaging. In the follow-up, the patients were diagnosed as having Parkinson's disease (PD, n = 25), dementia with Lewy bodies (DLB, n = 6), multiple system atrophy (MSA, n = 13), progressive supranuclear palsy (PSP, n = 8), corticobasal degeneration (CBD, n = 9), and essential tremor (ET, n = 11). Using the iteratively estimated optimal cutoffs, DAT was reduced in 57/61 PS patients, whereas all ET patients were identified as "normal". Reduced D2 receptor binding had 7/13 patients with MSA, 6/8 patients with PSP, 2/9 patients with CBD and no ET, PD or DLB patients. FP-CIT SPECT allows an accurate detection of nigrostriatal affection in neurodegenerative PS. IBZM SPECT is useful to approve the diagnosis of PSP and MSA although a normal finding cannot exclude an atypical PS. IBZM SPECT seems to be of restricted value in CBD.

[Percutaneous vertebroplasty]

PURPOSE

To describe the procedure of percutaneous vertebroplasty and to present our first clinical results of patients treated for benign or malignant painful vertebral body disease.

MATERIAL AND METHODS

We performed percutaneous vertebroplasty in 31 painful lesions of the spine. Liquid bone cement was injected into the affected vertebral body using fluoroscopic guidance through a bilateral transpedicular approach. Etiology of the bone disease was assessed by biopsy. Pain intensity was assessed before and 1 week after the procedure by standardized catalogue.

RESULTS

Percutaneous vertebroplasty was performed in 17 thoracic and in 14 lumbar spine bodies of benign (n = 23) or malignant (n = 8) disease; no clinically relevant complications occurred. All patients reported significant pain relief 1 week after the intervention. One week after treatment, patients were pain-free in 15/31 vertebral bodies, and reported mild residual pain not necessitating narcotic medication in 16/31 cases.

CONCLUSION

In accordance with the literature, percutaneous vertebroplasty proved to be a highly effective, minimal invasive interventional procedure to treat severely painful bone lesions of benign and malignant origin.

Removal of contrast media by different extracorporeal treatments

BACKGROUND

Although the capability of extracorporeal treatments after administration of contrast media to prevent radiocontrast-induced nephropathy is controversial, haemodialysis is performed in many institutions after radiographic procedures. There are conflicting reports on the efficacy of different dialysers and treatment modalities to remove contrast media.

METHODS

We compared the contrast medium-removing ability of different extracorporeal treatments in a randomized trial. Thirty-nine patients on chronic renal-replacement therapy or with chronic renal failure were randomized to receive low-flux haemodialysis (Low-HD, n=10), high-flux haemodialysis (High-HD, n=10), online haemodiafiltration (HDF, 10 litre substitution, n=10) and online haemofiltration (HF, 18 litre substitution, n=9) after administration of contrast medium during routine radiological procedures. Plasma concentrations of contrast medium (iopromide or iomeprol) were measured by energy-dispersive X-ray fluorescence analysis.

RESULTS

The extraction ratio for contrast media was 0.64+/-0.1 for Low HD (P<0.05 vs. High-HD and vs. HDF), 0.74+/-0.1 for High-HD (P<0.05 vs. HF), 0.81+/-0.1 for HDF (P<0.05 vs HF), and 0.62+/-0.1 for HF. Mean extracorporeal plasma clearances were 82+/-2 for Low-HD (P<0.05 vs. High-HD and vs HDF), 100+/-2 for High-HD, 115+/-4 for HDF (P<0.05 vs. HF), and 86+/-5 ml/min for HF.

CONCLUSIONS

We conclude that HDF and High-HD remove contrast media more effectively than Low-HD and HF during the time of each treatment session. However, whether this is also true for the overall elimination of contrast media by these different procedures needs to be addressed in future studies, by a precise assessment of the drug time course after the session.

Arterial switch procedure for D-transposition of the great arteries: quantitative midterm evaluation of hemodynamic changes with cine MR imaging and phase-shift velocity mapping-initial experience

PURPOSE

To evaluate cine magnetic resonance (MR) imaging and phase-shift velocity mapping for assessment of the hemodynamic relevance of stenotic segments or specific hemodynamic changes in the great vessels after an arterial switch procedure for correction of D-transposition of the great arteries.

MATERIALS AND METHODS

Twenty consecutive patients (age range, 2-17 years) with an acoustic window that was insufficient for Doppler transthoracic echocardiography were included in the study. Flow and diameter measurements of the pulmonary arterial trunk and its primary branches were performed with phase-shift velocity mapping and cine MR imaging.

RESULTS

There were good correlations between pressure gradients in the pulmonary arteries estimated with MR imaging and those measured with Doppler echocardiography (r = 0.83, n = 15) and cardiac catheterization (r = 0.90, n = 13). Cine MR imaging revealed that the diameters of the right and left pulmonary arteries decreased with the expansion of the aorta during systole, which increased the peak velocity. This temporary stenosis was more severe in the right than in the left pulmonary artery and was accompanied by a significantly (P <.05) lower volume flow in the right artery.

CONCLUSION

The anatomic situation after arterial switch repair tended to produce temporary stenoses in the primary pulmonary arterial branches, with significant changes in hemodynamics. These changes may affect the long-term outcome and go undetected with other imaging modalities.

Successful recanalization of late portal vein thrombosis after liver transplantation using systemic low-dose recombinant tissue plasminogen activator

Portal vein thrombosis (PVT) is an infrequent complication following hepatic transplantation. However, deterioration of liver function and accompanying complications may be life threatening. Several attempts of surgical or percutaneous transhepatic procedures have been described. In some cases high dose fibrinolytic regimens have been successful. We describe the case of a male liver recipient with recurrent liver fibrosis due to hepatitis B reinfection and late portal vein thrombosis 45 months after transplantation. Complete recanalization was achieved using systemic low dose recombinant tissue plasminogen activator (rt-PA).

Contribution of color and power Doppler sonography to the differential diagnosis of acute and chronic rejection, and tacrolimus nephrotoxicity in renal allografts

The aim of the present study was to differentiate acute rejection, chronic rejection, and tacrolimus nephrotoxicity with color and power Doppler imaging of renal transplants. One hundred examinations were obtained from 45 patients. Pulsatility and resistive indices were calculated from color Doppler images. The grade of renal vascularization was quantified using computer-assisted pixel analysis in a rectangular region-of-interest. The percentage of vessel-covered renal parenchyma (POV) was calculated using a histogram that discriminated renal vessels from renal parenchyma via power Doppler images. Furthermore, the distance from the most peripherally located vessels to the renal capsule (PVD) was measured. A reduced POV < or = 55% proved to be the best discriminator when chronic rejection was suspected (sensitivity 79%, specificity 87%). Tacrolimus nephrotoxicity showed not only a moderate elevation of the Doppler signal but also an increased PVD > or = 3.9 mm and a normal POV. We conclude that the evaluation of renal vessels by power Doppler images improves diagnostic accuracy for patients with renal allografts.

D-galactose-based signal-enhanced color Doppler sonography of breast tumors and tumorlike lesions

RATIONALE AND OBJECTIVES

This study sought to evaluate prospectively the diagnostic potential of unenhanced and enhanced color Doppler and power Doppler for the differentiation of tumors and tumorlike lesions of the breast.

METHODS

Ninety-two patients with 110 tumors or tumorlike lesions of the breast were investigated by unenhanced and enhanced color and power Doppler ultrasound. The sonomorphologic aspects of vascularization were analyzed. In addition, maximal systolic frequency shift, resistance, and pulsatility indices were determined.

RESULTS

In 15 (24%) of 63 primary carcinomas, 15 (68%) of 22 fibroadenomas, and all (100%) of 14 postoperative lesions, the sonomorphologic analysis for the differential diagnosis of breast tumors was improved after contrast enhancement in color Doppler mode. In comparing unenhanced color Doppler to power Doppler, the latter was found to be slightly superior (sensitivity, 60% vs. 67%; specificity, 39% vs. 45%, respectively); after enhancement, both modes were equivalent (sensitivity, 100% vs. 100%; specificity, 95% vs. 95%, respectively). Signal enhancement resulted in a significant improvement in sensitivity and specificity (P < 0.01). Typical signs of malignancy were irregular vessel calibers, serpiginous courses, penetration of the tumor's margin, and irregular reticular vascularization. The quantitative parameters proved not to be helpful for the differential diagnosis of breast tumors.

CONCLUSIONS

By improved analysis of the vascularization pattern, d-galactose-enhanced color Doppler sonography was found to provide more reliable differential diagnostic information than unenhanced Doppler ultrasound in tumors and tumorlike lesions of the breast.

[Use of high resolution color Doppler sonography in diagnosis of temporal arteritis]

PURPOSE

To define sonographic signs of arteritis temporalis using color coded duplex sonography.

METHODS

20 patients with clinically suspected temporal arteritis were examined with color coded Doppler ultrasound prior to temporalis biopsy. The investigation included the temporal artery on both sides and documentation was performed with color prints of the longitudinal orientation of both temporal arteries. All patients had an unilateral biopsy of the temporal artery.

RESULTS

6/20 patients had histologically confirmed temporal arteritis. All patients showed a paravasal zone of lower echogenicity (halo-sign) along the temporal artery. 12/14 patients without temporal arteritis showed no halo-sign. However, a halo-sign was found in 2/14 patients without temporal arteritis which could not be distinguished from the halo-sign observed in patients with temporal arteritis.

CONCLUSIONS

A halo-sign could be detected in the majority of patients with arteritis temporalis in concordance with the recent published findings of Schmidt et al. However, a definite specificity of this halo-sign must be rejected.

[The diagnosis and imaging of the a. hepatica after orthoptic liver transplantation--a comparison of frequency-modulated and amplitude-modulated color Doppler sonography]

PURPOSE

We examined whether amplitude-modulated color Doppler (power Doppler) sonography provides a better anatomic imaging of the vascular course of the hepatic artery after liver transplantation.

PATIENTS AND METHODS

82 patients were examined with Doppler sonography after liver transplantation. The distal section of the hepatic artery was imaged both with frequency-modulated color Doppler (color Doppler) and power Doppler and a Doppler spectrum derived from each mode for determination of the flow velocity.

RESULTS

Native imaging of the hepatic artery was possible in 78/82 patients, in 2/82 patients only after administration of Levovist, and in 2/82 patients it could not be seen. In these two patients the diagnosis of hepatic artery occlusion was confirmed by angiography. The anatomic course was demonstrated more longitudinally by power Doppler than by color Doppler (p < 0.001; chi 2 test) which made the angle correction easier. A disadvantage of power Doppler was the lack of image contrast to the portal veins; thus evaluation of the vascular course in this section was better possible with color Doppler by means of a specifically generated aliasing in the flow of the hepatic artery (p < 0.001; chi 2 test). Determination of the flow velocity showed no significant differences between color and power Doppler supported duplex sonography.

CONCLUSIONS

The combined use of color Doppler and power Doppler improves visualization of the hepatic artery after liver transplantation. The lack of visualization of the vessel after administration of Levovist is diagnostic for occlusion of the vessel.

[Blood flow quantification in hemodialysis shunts by phase contrast magnetic resonance angiography (PC-MRA) compared with duplex sonography]

PURPOSE

Aim of this study was to evaluate whether phase contrast MR angiography (PC-MRA) could provide additional functional information besides morphology in the assessment of haemodialysis fistulae.

MATERIAL AND METHOD

Twenty-two patients (11 male, 11 female), aged 22-77 years, were examined. MR images were obtained with a 1.5 T Gyroscan ACS-NT (Philips, Best, Netherlands) using a high-resolution wrap-around coil. In addition to MRA blood-flow measurements were performed with a gradient-echo sequence (TR 14 ms, TE 5-5.5 ms, flip-angle 15 degrees, 6 mm slice thickness, retrospective gating, matrix 96:128) in the venous and arterial section of the fistulae. Doppler flow measurements were performed at the same position with a Sonoline Elegra (Siemens AG, Erlangen) using a 7.5 MHz transducer.

RESULTS

Both methods of flow-volume measurements showed a good correlation (r = 0.94 in the arterial section, r = 0.90 in the venous section, p < 0.001). The average calculated blood flow was measured 11% (arterial section) and 12.8% (venous section) higher with Pulsed Waved Doppler as compared to PC-MRA.

CONCLUSION

PC-MRA with a high-resolution wrap-around coil is a reliable method for measuring functional parameters like flow-volume and flow velocity in haemodialysis fistulae and a useful complement to the visualisation capabilities of MRA.

Loss of dopamine-D2 receptor binding sites in Parkinsonian plus syndromes

This study analyzed temporal changes of striatal dopamine-D2 receptor binding during the course of different extrapyramidal movement disorders using 123I-iodobenzamide (IBZM) SPECT.

METHODS

Eighteen patients (9 with Parkinson's disease, 9 with parkinsonian plus syndrome) were followed for 11-53 mo. Dopamine-D2 receptor binding was assessed using 123I-IBZM SPECT at the beginning and at the end of the follow-up period. SPECT data were acquired 120 min postinjection of 3-5 mCi 123I-IBZM. A semiautomated algorithm was applied to the raw data for semiquantitative evaluation of regional cerebral receptor binding.

RESULTS

Intraobserver (r = 0.992) and interobserver (r = 0.930) variance was low for the semiautomated interpretation of the SPECT examination of the dopaminergic D2 receptor binding, reflecting a highly reproducible SPECT algorithm. Mean specific dopamine-D2 receptor binding was lower in patients with parkinsonian plus syndrome compared to patients with Parkinson's disease on the initial (p < 0.001) as well as the follow-up study (p < 0.001). In patients with Parkinson's disease, we observed an unaffected receptor binding compared to a reduced binding of radiotracer in patients with parkinsonian plus syndrome during the course of the disease (p < 0.001).

CONCLUSION

During the follow-up, patients with Parkinson's disease showed a constant dopamine-D2 receptor binding. In contrast, patients with parkinsonian plus syndrome revealed a decline of the binding of dopamine-D2 receptor. These findings are in agreement with histopathological data that demonstrated a preserved dopamine-D2 receptor status in patients with Parkinson's disease and a decline of the dopamine-D2 receptors in patients with parkinsonian plus syndrome. SPECT examinations using 123I-IBZM are useful for assessing dynamic changes of dopamine-D2 receptors in extrapyramidal movement disorders. Semiquantitative SPECT evaluations may provide valuable information for clinical management and prognosis of the patient with extrapyramidal movement disorders.

[Imaging tumor extension of renal cell carcinomas with magnetic resonance tomography. Improved tumor-tissue contrast with Gd-DTPA-assisted spin-echo sequences and simultaneous fat suppression]

PURPOSE

To evaluate the use of contrast-enhanced T1-weighted images with fat suppression (T1FS) to improve the contrast-to-noise ratio of renal cancer and renal parenchyma as well as perirenal fat.

METHODS

25 patients with histologically proven unilateral renal cancer after nephrectomy were examined before surgery. In addition to plane and contrast-enhanced T1-weighted as well as T2-weighted spin-echo images, all patients had T1 FS immediately after administration of Gd-DTPA in two planes. The contrast-to-noise ratio was calculated using circular regions-of-interest which outlined the tumor, the renal parenchyma, pyelon, and the perirenal fat.

RESULTS

T1 FS significantly improved the contrast-to-noise ratio of renal cancer and renal parenchyma compared to all conventional spinecho sequences (p < 0.001; Wilcoxon-Test). Compared to contrast-enhanced T1-weighted images without fat-suppression T1 FS yielded a higher CNR of the tumor, the perirenal fat and the pyelon. Another advantage was the absence of the chemical-shift artifact which is mostly pronounced in T2-weighted images and a reduced number of observed artifacts due to breathing.

CONCLUSION

T1 FS should replace conventional contrast-enhanced T1-weighted spin-echo images in the work-up of renal cancer using MRI.

[Color-coded signal-enhanced duplex ultrasonography of space-occupying intramammary processes]

PURPOSE

Prospective comparison of plain and signal-enhanced frequency and amplitude-modulated colour Doppler ultrasound of intramammary tumours to evaluate new criteria for diagnostic analysis.

METHODS

Frequency and amplitude-modulated colour Doppler examination with qualitative and quantitative analysis of 80 potentially malignant intramammary lesions were performed before and after application of d-galactose.

RESULTS

Signal-enhanced sonography revealed a typical vessel morphology of primary and recurrent breast cancer facilitating differential diagnosis. In 18 (frequency modulated US) or 16 (amplitude modulated US) of 51 carcinomas, the typical malignant vascularisation structure was sufficiently visible only after application of the signal enhancing agent. In 50% of the fibroadenomas, Doppler analysis of the vessels was possible only after application of d-galactose.

CONCLUSION

The application of d-galactose provides additional criteria for the differential diagnosis of breast lesions due to improved visualisation of the vascularisation structure.

Quantitative estimation of I-123-Iomazenil receptor binding in temporal lobe epilepsies using two SPECT acquisitions--comparison with the regional cerebral blood flow and a compartment model

AIM

To compare published fractional rate constants of I-123-Iomazenil (IMZ) and C-11-Flumazenil (three-compartment/four-parameter model) with a I-123-Iomazenil receptor index calculated from two SPECT acquisitions and to compare the receptor index of the epileptogenic area with the contralateral side in patients with unilateral temporal lobe epilepsies.

METHODS

28 patients were studied. 13/28 patients had a drug-resistant unilateral temporal lobe epilepsy with a successful focus localisation performed by an extensive video/EEG monitoring. 15 other patients with clinically suspected focal epilepsy and a normal MRI and IMZ SPECT scanning were used as controls. SPECT scanning was performed in all patients 15 and 100 min after intravenous injection of 111 MBq IMZ and 10 min after application of 740 MBq Tc-99m-HMPAO. Quantification of the regional uptake was performed using ROI-technique and the specific and non-specific binding of IMZ was calculated. The receptor index was calculated by the difference of the specific binding from 15 to 100 min p.i. divided by the time interval.

RESULTS

The receptor index showed a linear correlation with recently published fractional rate constants k3 (r = 0.69 and 0.67; p = 0.15) and a moderate correlation with the k4 constant (-0.53 and -0.43; p = 0.28) by the means of C-11-Flumazenil PET and I-123-Iomazenil SPECT studies, respectively. However, statistical significance was not reached due to the few data points available from the published reports. Furthermore, the IMZ receptor index was lower in the epileptogenic area of patients with unilateral temporal lobe epilepsies compared with their contralateral side (p = 0.02; Wilcoxon-test). The IMZ receptor index showed a weak correlation with the regional cerebral blood flow independent of the evaluated region (r < 0.4; p < 0.05).

CONCLUSION

The IMZ receptor index indicated to be a simple routine approach to estimate the fractional rate constant k3 (r = 0.67). The lower value of the receptor index within the epileptogenic area might be due to a lower receptor density. However in further studies, IMZ might be a helpful tool to find out subtle changes of the receptor affinity due to its approximately 30-fold higher ligand-receptor affinity compared to C-11-Flumazenil.

Do ultrasonic contrast agents artificially increase maximum Doppler shift? In vivo study of human common carotid arteries

The aim of this study was to establish whether an increase of maximum Doppler shift occurs in the human common carotid artery after the administration of Levovist, an ultrasonographic echo enhancer. Twenty common carotid arteries of 10 patients were examined. Spectral Doppler waveform examinations were performed before and after administration of Levovist using an Acuson 128 XP 10 and a 7.0 MHz transducer probe. Time averaged mean velocity, peak velocity, maximum Doppler shift, and spectral Doppler indices (pulsatility index, resistive index, systolic-diastolic ratio) were assessed. No significant changes in any of the measured parameters, including maximum Doppler shifts, peak velocity (P = 0.35, Wilcoxon rank sum test), pulsatility indices (P = 0.70), resistive indices (P = 0.98), or other spectral indices, were found. We conclude that an increase in Doppler shift does not inevitably occur after the administration of a signal enhancer when examining the human common carotid artery.

[Vascularization patterns in focal liver lesions: comparison of plain and signal-enhanced amplitude-modulated color duplex ultrasonography]

PURPOSE

Morphology of focal liver lesions was studied by power Doppler. Plain images and images after i.v. application of galactose-based microbubbles (Levovist, Schering AG) were compared.

METHODS

21 patients with focal liver lesions were studied by power Doppler before and after application of the signal enhancer.

RESULTS

In lesions that showed short pulsations in plain studies, vascular structures were visible after application of the signal enhancer. In hepatocellular carcinomas, multiple arteries with small diameter became visible. Peripheral veins were detected in metastases. A large feeding artery was detected in 1/2 haemangiomas with flow and in a focal nodular hyperplasia.

CONCLUSION

In comparison to plain amplitude-modulated colour-coded duplex ultrasound, vascular patterns of focal liver lesions were more clearly visible after injection of a signal-enhancer.

[Contrast agent enhanced duplex ultrasonography: visualization of the hepatic artery after orthotopic liver transplantation]

PURPOSE

A prospective study was carried out to determine whether an improved assessment of the anatomy and flow velocity in the hepatic artery could be achieved by the administration of a capillary transversing contrast agent (Levovist) in patients after orthotopic liver transplantation.

METHODS

In 21 (62%) of 34 patients after liver transplantation, only an insufficient visualisation of the hepatic artery was achieved. Therefore, a capillary transversing contrast agent was administered intravenously. Pre- and post-contrast peak velocity and Doppler frequency shift in the proper hepatic artery were measured and image quality of colour and spectral Doppler was assessed by a qualitative scale.

RESULTS

Image quality, with complete visualisation of hepatic artery in 79% (precontrast 38%) of all cases, was significantly improved (p < 0.01 (Wilcoxon test)) by the administration of a contrast agent.

CONCLUSIONS

Visualisation of the hepatic artery after orthotopic liver transplantation can be improved by the administration of Levovist. It allows a reliable measurement of peak velocity and Doppler frequency shift and helps to avoid further imaging.

[Magnetic resonance tomography in patients with Parkinson's disease and Parkinson-plus syndromes]

PURPOSE

To define characteristic MR-findings in patients with clinically typical extrapyramidal movement disorders.

METHODS

15 patients with Parkinson's disease (PD), 9 with multisystem atrophy (MSA), and 6 with progressive supranuclear palsy (PSP) underwent MRI using a 1.5 T. Magnetom unit. Two investigators analysed the images with special regard to global and/or focal atrophy and to changes in signal intensity of the CNS in the consensus mode. Normal images of 10 subjects served as controls to patient's images.

RESULTS

In all patients with PSP and MSA characteristic pathological findings on MRI were observed including regional changes within the extrapyramidal nuclei. In contrast all patients with PD had an unremarkable MRI study of the CNS.

CONCLUSION

MRI enables us to define characteristic morphological changes of the brain in patients with extrapyramidal movement disorders. Early recognition of these findings avoids misdiagnoses in patients who are difficult to diagnose.

[Determining the depth of infiltration in urinary bladder carcinoma with contrast medium enhanced dynamic magnetic resonance tomography. With reference to postoperative findings and inflammation]

OBJECTIVE

The purpose of this study was to evaluate dynamic contrast-enhanced magnetic resonance imaging for the staging of urothelial bladder carcinoma and to compare it with plain and contrast-enhanced spin-echo MRI.

METHODS

Pre-operative MRI was carried out in 62 patients. Post-operative histological examination confirmed bladder carcinoma in 50/62 patients. Carcinoma was excluded in 12 patients. Beside spinecho MRI a dynamic contrast-enhanced study was performed immediately after IV application of Gd-DTPA using 10 sequential FLASH-2Dsequences, each with a duration of 15 s. Images were evaluated visually by three radiologists in a blinded fashion.

RESULTS

In 41/62 patients pre-operative tumor staging with the dynamic contrast-enhanced study was confirmed by the histological examination after surgery. MRI with spinecho sequences yielded correct staging in 30/62 patients (P = 0.028). Staging of superficial bladder cancer was more accurate with dynamic contrast-enhanced MRI than with conventional MRI (P = 0.024). Overstaging was observed in some patients with stage pT1 tumors. Furthermore, postoperative changes of the bladder wall could be differentiated from cancer due to significantly earlier contrast enhancement of bladder cancer compared with postoperative and inflammatory alterations (P < 0.001).

CONCLUSION

Contrast-enhanced dynamic MRI is a helpful addition in the presurgical T-staging of bladder cancer.

The value of magnetic resonance imaging in the diagnosis of suspected penile fracture with atypical clinical findings

PURPOSE

We studied the use of magnetic resonance imaging (MRI) in the diagnosis of suspected penile fracture.

MATERIALS AND METHODS

Penile fracture diagnosis was based on classic history and typical physical signs in 8 patients who were treated surgically without any further diagnostic procedure. Sonography, cavernosography and MRI were performed in 4 patients with equivocal findings.

RESULTS

Only MRI identified rupture of the corpus cavernosum in all 4 cases.

CONCLUSIONS

MRI is the most accurate imaging procedure when penile fracture is suspected but clinical findings are unusual.

[Preoperative staging of bladder carcinomas with Gd-DTPA-supported dynamic magnetic resonance tomography. Comparison with plain and Gd-DTPA-supported spin-echo sequences]

PURPOSE

Evaluation of dynamic Gd-DTPA enhanced MR imaging in the staging of bladder cancer.

METHODS

We studied 40 patients with histologically proven bladder cancer. All patients were examined with routine T1- and T2-weighted MRI and late Gd-DTPA enhanced T1-weighted MRI. Additionally, a dynamic study was performed with 10 subsequent short FLASH-2-D gradient echo sequences without delay immediately after bolus injection of Gd-DTPA. Signal intensities of the tumour and of the surrounding tissue as well as image contrast parameters were quantified.

RESULTS

The dynamic study showed a higher accuracy in the evaluation of stage pTa to pT2 cancer compared to spin echo MRI (63% and 46%, respectively) and no difference regarding the sensitivity (87.5%). However, overstaging was a problem with both modalities. The contrast-to-noise ratio of bladder tumour and muscle was equal or significant higher with the dynamic study compared to spin echo MRI. A higher signal-to-contrast ratio of bladder tumour and bladder muscle was calculated for the dynamic study compared with the spin-echo MRI (p < 0.01; Mann-Whitney U test).

CONCLUSION

Dynamic Gd-DTPA enhanced MRI is recommended to be used additionally in the preoperative staging of bladder neoplasms.

[MR urography with the T2-weighted turbo-spin-echo sequence]

Tumor-induced dilatation of the urinary tract is difficult to diagnose in the distal part of the ureter, including the stenosis, by ultrasound and X-ray. Often on account of renal insufficiency and allergy, i.v.-contrast media cannot be used. The present study should show the suitability of fast T2-weighted (turbo-) spin-echo sequences (T2-TSE) for MR-urography (MRU). Seven patients (62.3 +/- 6.1 years) were examined in the coronal plane with T2-TSE sequence (TR = 4500 ms, TE = 160 ms) and an MRU was calculated by using the MIP method (maximal intensity projection). This technique enabled urogram-like morphological representation of dilated urinary tract including stenosis in 6 of 7 patients. Assuming a high magnetic field homogeneity, MRU by using a T2-TSE-sequence, without i.v.-contrast media administration, can visualize the urinary tract dilatation and localize tumor-induced stenosis.

[Estimating patient dosage in radiologic examinations. Effective doses of the most frequent roentgen examinations]

The effective dose (E) measures the stochastic risk of radiation exposure from the viewpoint of the induction of cancer and genetic diseases. In order to compare this risk in roentgen examinations, the effective dose was calculated for the most frequent roentgen examinations. The calculations were performed with a mathematical human phantom for a standard patient. Acquisition parameters were chosen according to national recommendations. The highest values were found for the small bowel enema and lumbar myelography, the lowest values for X-rays of the cervical spine, the paranasal sinuses and the upper thigh.

Dopamine D2 receptor imaging with iodine-123-iodobenzamide SPECT in idiopathic rotational torticollis

The cause of idiopathic rotational torticollis (IRT) is not completely understood to date. However, basal ganglia are believed to be involved in the pathophysiology of IRT. To elucidate this disorder further, the value of iodobenzamide (IBZM) SPECT was studied for the evaluation of striatal dopamine D2 receptors in these patients.

METHODS

Striatal dopamine D2 receptor density was assessed in 10 patients with IRT using 123I-IBZM SPECT. The images were interpreted by a nuclear medicine physician initially to determine IBZM binding within the striatum and the cerebellum and, secondly, interstriatal IBZM binding. The results were correlated with the clinical parameters of the patients and compared with the results obtained from normal controls.

RESULTS

No difference was found in average, specific striatal IBZM binding (basal ganglia/cerebellum ratio) between patients and controls. However, interstriatal analysis of IBZM binding revealed a significantly higher binding in the striatum contralateral to the direction of the torticollis (p = 0.026, by chi-square test).

CONCLUSION

It was concluded that the striatal dopamine D2 receptor status is altered in patients with IRT.

[Preoperative evaluation of drug resistant focal epilepsies with 123I-iomazenil SPECT. Comparison with vidio/EEG monitoring and postoperative results]

SPECT with the benzodiazepine receptor antagonist 123I-Iomazenil was performed in 33 patients with intractable partial seizures for pre-operative evaluation. The results combined with MRI and 99mTc-HMPAO-SPECT findings were compared with the video-assisted EEG monitoring ("gold standard") which localised the focus in 25 patients. 11 patients underwent surgical resection of the epileptogenic area and became seizure-free for a period up to 13 months. The Iomazenil SPECT had a significantly higher sensitivity compared to 99mTc-HMPAO in the visualization of an epileptogenic area and should be regularly used in the diagnostic of medically intractable partial seizures.

[Osteoplastic bone metastases in prostatic carcinoma: magnetic resonance tomography and bone marrow scintigraphy]

MRI of the vertebral column was performed in 28 patients with histologically confirmed prostate carcinoma. Besides routine spin-echo sequences all patients were examined with gradient-echo sequences using the chemical shift mode. In addition, in all patients bone marrow scintigraphy (BMS) was performed, and all results were compared with routine bone scan (BS). In our study BMS was not superior to bone scan. In contrast, MRI scan revealed solitary metastases in two patients with negative BS and BMS. Osteoplastic metastases showed a contrast enhancement in the MRI and could be distinguished from benign alterations.

[123I-iomazenil- and 99mTc-HMPAO in the diagnosis of focal epilepsies: a comparison of untreated and treated patients]

The purpose of this study was to compare HMPAO- and IMZ-SPECT findings in treated and untreated patients with focal epilepsies. We examined 20 patients (untreated 13; treated 7). All patients had a normal CT and/or MRI scan. In all patients both whole-brain activity and regional count density (rcd) were evaluated by SPECT. Furthermore, the specific and non-specific binding of IMZ were calculated for each ROI and the results of both, treated and untreated patients were compared. Our data indicate that the normalized cerebral total binding of IMZ was significantly increased in all regions in the group of treated patients (p < 0.001). In contrast, no difference in the tracer binding was found with HMPAO-SPECT. We conclude that the difference in the IMZ-binding might be due either to exogenous or endogenous factors. In our study IMZ-SPECT had a higher sensitivity and a lower specificity in the detection of decreased rcd in areas with EEG findings that indicate an epileptogenic focus compared with HMPAO-SPECT.

Präoperative Bewertung pharmakoresistenter fokaler Epilepsien mit der 123J-Iomazenil-SPECT

Bei 33 Patienten mit therapieresistenten fokalen Epilepsien wurde präoperativ ein Video-unterstütztes Monitoring durchgeführt, das eine kontinuierliche EEG-Ableitung über sieben Tage beinhaltete. Als bildgebende Verfahren wurden neben einer kranialen MRT bei allen Patienten je eine SPECT-Untersuchung mit dem Blutflußmarker 99mTc-HMPAO und dem Benzodiazepin-(Bz)Rezeptorantago-nisten 123J-lomazenil eingesetzt. Die Ergebnisse der SPECT-Untersuchungen wurden visuell ausgewertet und mit der Lokalisation des anfallsgenerierenden Herdes durch das EEG-Monitoring (»Goldstandard«) verglichen, das bei 25 der 33 Patienten den Fokus lokalisieren konnte. 11 Patienten wurden bisher operiert und blieben postoperativ bis zu 13 Monate anfallsfrei. Die Untersuchung mit 123J-lomazenil war im Nachweis einer zum epileptogenen Areal korrespondierenden funktionellen Läsion dem Blutflußmarker 99mTc-HMPAO signifikant überlegen und sollte in der Diagnostik einen festen Platz einnehmen.

[[111In]-DTPA-D-phenylalanine octreotide SPECT for the scintigraphic imaging of enhanced somatostatin-receptor density in endocrine ophthalmopathy]

Recently, [111In]-DTPA-D-phenylalanine-octreotide was introduced for clinical use. This radioligand binds specifically to somatostatin receptors and is suitable for SPECT examinations. The aim of this study was to clarify whether an increased somatostatin receptor density can be imaged and quantified in patients with endocrine ophthalmopathy (e.o.). 7 patients between 34 and 55 years with e.o. at stages III to VI and 4 controls between 38 and 63 years were examined. All patients and controls received approximately 200 MBq [111In]-DTPA-D-phenylalanine-octreotide by IV injection. A SPECT examination was performed 4 hours after injection and a normalised tracer uptake (A(n)) was calculated for both orbitae. In patients with e.o. the values of A(n) were significantly higher compared with controls (P = 0.002). There was a correlation between A(n) and exophthalmus stages according to Hertel with r = 0.844 (P = 0.001). These results indicate that [111In]-DTPA-D-phenylalanine-octreotide SPECT might be useful for the in vivo assessment of an increased somatostatin receptor density in e.o. These findings could have an impact on the treatment with somatostatin analogous in e.o.

123J-Iomazenil- und 99mTc-HMPAO in der Diagnostik fokaler Epilepsien: Vergleich von unbehandelten und behandelten Patienten

Die Daten von insgesamt 20 Patienten mit fokalen Epilepsien (beh.: 7; unbeh.: 13) wurden mit dem Ziel ausgewertet, Unterschiede in der Bindung der Radiotracer HMPAO und IM घ zwischen behandelten und unbehandelten Patienten herauszufinden. CT und MIRT zeigten keine pathologischen Befunde. Bei allen Patienten wurden mittels SPECT die Gesamthirnaktivität und durch Anwendung der ROI-Technik regionale Impulsdichten (Rl) bestimmt und der spezifische und unspezifische Anteil der Rl des BZ-Antagonisten für jede Region berechnet. In der Gruppe der beh. Patienten konnte eine signifikant höhere normalisierte Gesamtbindung von IMZ gefunden werden (p <0,001). Die spezifische Bindung von IMZ und die Gesamtbindung von HMPAO zeigten keine Unterschiede zwischen beiden Gruppen. Die IMZ-SPECT hatte in unserem Kollektiv gegenüber der HMPAO-SPECT in bezug auf das EEG eine höhere Sensitivität bei geringerer Spezifität im Nachweis einer Minderanreicherung des Tracers in Arealen mit fokaler hypersynchroner Erregungssteigerung.

Modified surface-active monomers for adhesive bonding to dentin

PMGDM, a PMDM-type adhesive monomer, was synthesized from pyromellitic dianhydride and glycerol dimethacrylate. Only the para isomer of PMDM, a solid, is used in dental adhesives. The adhesive monomer PMGDM is a liquid and consists of a mixture of para- and meta isomers. This study shows that PMGDM has several advantages over PMDM. For example, the adhesive can be applied at a greater thickness, and additives and/or additional initiators for improved curing can be incorporated. Use of the liquid monomer PMGDM also provided a convenient means of varying the thickness of the adhesive layer between dentin and composite. The adhesive bonds were tested in both shear and tensile modes. PMDM was used as the control. The reliability of the bonds, as judged from the Weibull modulus and Weibull characteristic strength, was improved by (1) use of more concentrated solutions of PMGDM adhesive, (2) use of an adhesive thickness of about 25 microns, and (3) modification of PMGDM with a diluent monomer which is expected to enhance the degree of cure and/or the dentin-wetting properties of the adhesive resin.

NIR-spectroscopic investigation of water sorption characteristics of dental resins and composites

A near infrared (NIR) method using the 5200 cm(-1) absorption of water has been employed to examine water absorbed in photopolymerized dental resins and composites in the form of 0.01-cm- to 0.15-cm-thick specimens. The concentration, c [mol L(-1)], of absorbed water in specimens of thickness t [cm] was calculated by means of Beer's law, A = e ct. A is the NIR absorbance and e is the absorptivity of absorbed water. e depends on the environment of the water molecule and it is necessary to estimate e for water in each material. Water sorption was determined gravimetrically and correlated to the absorbance in the NIR spectrum. Once the relationship between e and water content was known for a material, water sorption was determined rapidly on very thin specimens for faster equilibration. Where dissolution of the specimen occurred, the solubility behavior of the specimen was evaluated from a comparison of NIR and gravimetric measurements. The NIR absorptivity, e, of water absorbed in a polymeric medium was found to be inversely related to the degree of hydrophilicity and hydrogen bonding capability of the polymer. The presence of water clusters in a polyethylene oxide methacrylate polymer was inferred from convex-up curvature in the plot of e vs. water content.

Filler systems based on calcium metaphosphates

Calcium metaphosphates (CMP's)--a unique class of phosphate minerals possessing polymeric structures, [Ca(PO3)2]n, and having refractive indices of approximately 1.54-1.59-- are optically compatible with resins such as BIS-GMA. In this study, several types of CMP's were prepared and evaluated for their potential as fillers for visible-light-activated (VLA) dental composites. The vitreous (V) and beta-crystalline forms of CMP were prepared by controlled thermolysis of monocalcium phosphate monohydrate, Ca(H2PO4)2.H2O. Hybrid fillers were also prepared by thermal methods. Fillers, characterized by IR spectroscopy and optical microscopy, were prepared in several size ranges (e.g., 1-100 microns). VLA composites were formulated by use of both untreated and surface modified CMP's. V-CMP and its hybrids yielded composites which expanded when stored in water but were of low strength, e.g., diametral tensile strength, (DTS) = 8 MPa. beta-CMP composites were more moisture-resistant, had higher DTS's (from 12 to 33 MPa), and showed a tendency to arrest brittle fracture. These novel fillers have potential uses in resin-based materials such as dental composites, cements, and adhesives.