[Differential diagnosis of childhood osteomyelitis--classification according to scintigraphic, radiologic and magnetic resonance tomographic characteristics]. / Differentialdiagnostik der kindlichen osteomyelitis--Typisierung anhand szintigraphischer, radiologischer und magnetresonanztomographischer Charakteristika.

We present a retrospective study on children with the final diagnosis osteomyelitis, who have been examined in Tübingen from 1985 to 1991. The different types of infantile osteomyelitis were classified due to the causative organism and findings in 3-phase scintigraphy and X-ray films. For the chronic type of osteomyelitis the study was extended to the years from 1979 to 1991 and the results of an earlier report were included. We worked up 17 cases of acute/peracute osteomyelitis, including 5 cases of early infancy, 2 cases of tuberculosis, 2 Brodie's abscesses, 5 plasmacellular types, 2 cases of primary chronic multifocal osteomyelitis (PCMO), and 5 cases of unspecific chronic osteomyelitis. All cases were examined with scintigraphy, X-ray films and in part with magnetic resonance tomographic imaging. In 23 cases scintigrams and X-ray films were performed in the follow-up. We show the importance of scintigraphy for the early detection and localisation of osteomyelitis, the importance of findings on X-ray films for the specific diagnosis of osteomyelitis, and the importance of magnetic resonance tomography for high-resolution detection of the expansion of osteomyelitis.

Catecholamine secreting glomus tumor detected by iodine-123-MIBG scintigraphy.

We report the case of a 41-yr-old woman who presented with arterial hypertension and tinnitus in the right ear synchronous with pulse. She had previously undergone surgery for suspected pheochromocytoma without positive therapeutic effect. CT and MRI revealed a homogenous tumor with contrast enhancement in the right hypotympanon and foramen jugulare, and [123I]metaiodobenzylguanidine (MIBG) scintigraphy demonstrated strong tracer uptake in the same area. Selective venous sampling of catecholamines in the ipsilateral jugular vein confirmed the tumor to have originated from hormone production.

Multiphoton ionization of molecules: A comparison between femtosecond and nanosecond laser pulse ionization efficiency.

Multiphoton ionization mass spectra of nonvolatile molecules laser desorbed into a supersonic beam are recorded. It is shown by indirect measurements that the laser desorption of neutrals is not mass limited, but lead to the formation of neutrals with intesities large enough for intense signals. To investigate the efficiency of the multiphoton ionization process with varying laser pulse durations, simultaneous laser pulses of 500 fs and 5 ns or 100 fs and 5 ns have been applied to the neutral beam. The energies of both femtosecond and nanosecond laser pulses are held in a comparable magnitude, and thus produce, in the resulting ion intensity, very large differences up to 4 orders of magnitude. For larger evaporated molecules (> 500 u) the ionization efficiency from nanosecond laser pulses drops significantly in comparison to femtosecond laser pulse excitation. A variety of possible reasons for the different ionization and dissociation behavior in femtosecond and nanosecond laser pulse excitations are discussed in this paper. It is rationalized that even with very short laser pulses and large molecules the "ladder switching model" for ionization and fragmentation is valid.

Incidental finding of a hepatic lesion: differential diagnostic problems for fibrolamellar hepatic carcinoma.

We report the case of a 39-yr-old female with a liver lesion that was incidentally detected by ultrasound. Examination of biopsy specimens revealed focal nodular hyperplasia. A metastatic tumor in the right os ilium developed in the following weeks and showed specific uptake of 99mTc-hepatic 2,6-dimethyliminodiacetic acid (HIDA), suggesting metastasis from a differentiated hepatocellular carcinoma. The final pathologic diagnosis was multifocal, solid and glandular hepatocellular carcinoma, partly differentiated as fibrolamellar carcinoma, and an osseous metastasis from the differentiated hepatocellular carcinoma.

Superparamagnetic iron oxide: detection of focal liver lesions at high-field-strength MR imaging.

AMI-25 was evaluated at 1.5 T as a superparamagnetic iron oxide contrast agent for the liver. Sixteen patients with up to five suspected focal liver lesions were examined with T1-, proton-density-, and T2-weighted spin-echo sequences before and after intravenous administration of AMI-25 (15 mumol/kg iron). The contrast-to-noise ratio (C/N) increased from 1.8 to 3.5 on 600/15 (TR msec/TE msec) images and from 1.7 to 7.9 on 2,500/15 images after AMI-25 administration (P < .01). C/N did not change significantly on 2,500/90 images. Two blinded readers counted the number of lesions visible on unenhanced and contrast-enhanced images, with the 32 sets of images of the 16 patients presented in random order. Both readers identified more lesions on AMI-25-enhanced images, but the difference was not statistically significant (P > .05). Two patients reported minor side effects (flushing, sensation of heat, lower back pain). On the basis of the results obtained in a limited number of patients, the authors conclude that at 1.5 T, AMI-25 does not significantly improve the detection of focal liver lesions on conventional spin-echo images.

[The MR tomography of focal liver lesions with the superparamagnetic contrast agent AMI-25 at 1.5 tesla]. / MR-Tomographie fokaler Leberläsionen mit dem superparamagnetischen Kontrastmittel AMI-25 bei 1,5 Tesla.

Superparamagnetic iron oxide particles (AMI-25) were evaluated as a liver contrast agent in high-field MR imaging (1.5 T). 16 patients with up to 5 presumed focal liver lesions (liver metastases n = 8, HCC n = 5, Klatskin tumours n = 2, FNH n = 1) received 15 mumol Fe/kg BW intravenously and were examined via standard T1- and T2-weighted spin-echo sequences. Quantitative image analysis showed a post-contrast increase of the contrast-to-noise ratio (C/N) from 1.6 to 7.4 on SE 2,500/15 images (p < .05). However, C/N was in the same range on plain SE 2,500/90 scans. Blind evaluation by two independent readers revealed that AMI-25-enhanced images did not provide a significantly increased number of lesions. Two patients reported minor, self-limited side-effects (flush, back pain). We conclude that in contrast to reports at mid-field MR imagers, the use of AMI-25 at 1.5 T does not significantly improve the detection of focal liver lesions on conventional SE images.

Mn-DPDP-enhanced MR imaging of malignant liver lesions: efficacy and safety in 20 patients.

Twenty patients with malignant liver lesions underwent magnetic resonance (MR) imaging with manganese (II) DPDP [N,N'-dipyridoxylethylenediamine-N,N'-diacetate 5,5'-bis(phosphate)] to evaluate the safety and efficacy of the contrast agent. In two groups of 10 patients each, 5 mumol/kg Mn-DPDP was administered intravenously (3 mL/min) at a concentration of either 50 or 10 mumol/mL. T1- and T2-weighted images were obtained with a 1.5-T imager. Six patients reported a total of eight instances of side effects (flush, feeling of warmth, metallic taste) of which seven occurred at the 50 mumol/mL concentration. A significant decrease in alkaline phosphatase levels 2 hours after injection was recorded. On T1-weighted images, the 10 mumol/mL formulation yielded significantly greater increases in contrast-to-noise ratio (79.8%-137.5%) than the 50 mumol/mL formulation (46.2%-86.6%). In a blinded reader study of 10 patients with one to five lesions each, no lesion was missed on Mn-DPDP--enhanced T1-weighted images; however, four false-positive foci were identified. The authors conclude that slow administration of 5 mumol/kg Mn-DPDP at a concentration of 10 mumol/mL is safe and efficient enough to proceed to further clinical trials.

[Manganese DPDP as a contrast medium for MR tomography of focal liver lesions. Tolerance and image quality in 20 patients]. / Mangan-DPDP als Kontrastmittel für die MR-Tomographie fokaler Leberläsionen. Verträglichkeit und Bildgebung bei 20 Patienten.

Twenty patients with focal liver lesions (18 metastases, 1 hepatocellular carcinoma, 1 cholangiocarcinoma) were given manganese DPDP as part of a multicentric phase II study of paramagnetic hepatobiliary MR contrast media. 5 mumol/kg manganese DPDP were injected into 10 patients in a concentration of 50 mumol/ml or 10 mumol/ml (3 ml/min). Blood pressure, pulse rate, ECG, respiratory rate, body temperature, blood and serum parameters and the patients' subjective feelings were recorded. MRI was performed with 1.5 T using T1- and T2-weighted sequences. 6 patients reported 8 side effects (flushing, feeling of warmth, metallic taste); 7 of these were produced by the 50 mumol concentration. Two hours after injection there was a significant reduction in alkaline phosphatase which was no longer present after 24 hours. On T1-weighted images manganese DPDP resulted in marked improvement in the contrast difference between the lesions and the liver parenchyma which resulted in a marked increase in the signal to noise ratio. Comparing the two concentrations, better results were obtained by the lower concentration. Extrahepatic uptake was found in the gallbladder, duodenum, pancreas, kidneys, gastric mucosa and myocardium. Manganese DPDP in a concentration of 10 mumol/ml and a dose of 5 mumol/kg is a well tolerated contrast medium which improves the demonstration of focal liver lesions in view of its distribution and uptake. The mechanisms for the transitory side effects require further studies.

Magnetic resonance imaging detection of an experimental pulmonary perfusion deficit using a macromolecular contrast agent. Polylysine-gadolinium-DTPA40.

RATIONALE AND OBJECTIVES: This study was designed to evaluate the potential of a blood-pool magnetic resonance (MR) contrast agent, polylysine-gadolinium-DTPA40 (polylysine-Gd-DTPA40) for detecting pulmonary perfusion defects. MATERIALS AND METHODS: Pulmonary emboli were induced in 10 rats by venous injection of 0.2 mL of air. Axial spin-echo images were acquired (TR = 800 mseconds; TE = 6 mseconds) before and after air injection and serially after the administration of polylysine-Gd-DTPA40. The embolism model was confirmed by scintigraphy using 99mTc-macroaggregated albumin. RESULTS: Signal intensity differences between normal and embolized lungs before and after the air injection were less than 25%. After polylysine-Gd-DTPA40 administration, signal intensity of the perfused lung increased more than 200%, whereas the embolized lung increased by only 25%. Signal intensities of the perfused lung remained stable for 1 hour, whereas signal intensities of the embolized lung gradually increased for 20 minutes as the air embolus dissolved. CONCLUSION: Magnetic resonance imaging (MRI) enhanced with a macromolecular blood-pool contrast agent can be used to detect acute pulmonary embolism in a confirmed animal model.

Iron-dextran as a magnetic susceptibility contrast agent: flow-related contrast effects in the T2-weighted spin-echo MRI of normal rat and cat brain.

Iron-dextran (1 mmol Fe/kg) was used as an intravascular, paramagnetic contrast agent in rat and cat brain in conventional spin-echo T2-weighted (TR 2800/TE 100) 1H magnetic resonance imaging. The resulting images displayed differential decreases (30-50%) in intensity whose pattern was similar to that obtained with the superparamagnetic particulate iron oxide AMI-25 (0.18 mmol Fe/kg). Postcontrast images displayed improved anatomic detail, and contrast effects were observed to be greater in cortical and subcortical gray matter than in adjacent white matter. Intravenous injection of acetazolamide after administration of iron-dextran caused a small additional decrease in image intensity. Measurement of whole blood and plasma at 5 min postinjection of either contrast agent revealed significant increases in their volume magnetic susceptibilities. The contrast effect appears to be related to magnetic susceptibility changes brought about by the iron-dextran; it has both blood volume and blood flow components. The static model of magnetic susceptibility effects in brain capillaries is modified to include bolus flow of erythrocytes, providing a mechanism for the observed flow effects.

[Adrenocortical nodular hyperplasia as a cause of Cushing syndrome in the neonatal period]. / Adreno-corticale noduläre Hyperplasie als Ursache eines Cushing-Syndroms in der Neugeborenenperiode.

The case report of a female child born preterm (30th wk of gestation) who developed symptoms of Cushing's syndrome beginning in the neonatal phase is presented. The disease was caused by a unilateral adreno-cortical nodular hyperplasia and was successfully treated by unilateral adrenalectomy. Preoperative treatment with ketoconazole and metyrapone proved to be effective. Symptoms of Cushing's disease including hypertrophic cardiomyopathy were completely reversible within one month after surgery.

Detection with echo-planar MR imaging of transit of susceptibility contrast medium in a rat model of regional brain ischemia.

Gradient-refocused echo-planar magnetic resonance (MR) images (TE = 18 msec) were acquired in rats during bolus injection of iron oxide particles, and the first pass of the contrast agent through the brain was monitored. In control rats, contrast agent (0.1 mmol/kg iron) produced significant signal-intensity (SI) reduction over the right hemisphere and similar declines over the left. SI loss occurred first in the cortex and basal ganglia and later in the periventricular regions, along the midline, and in the thalamic zone. Sequential volume-localized proton spectra acquired during transit of 0.02 mmol/kg iron showed substantial reduction in SI, slight asymmetric broadening, and no change in chemical shift of the water resonance. In rats with unilateral occlusion of the middle cerebral artery, peak reduction in ischemic brain SI was to 70% +/- 9% of control, while normal brain SI was reduced to 18% +/- 2% (P less than .01), allowing distinction of the ischemic regions. The presence and location of injury were confirmed with diffusion-weighted imaging and postmortem vital staining. These results demonstrate abnormal transit profiles in a rat model of regional brain ischemia. Evaluation of dynamic contrast delivery patterns may provide unique information in early brain ischemia.

Contrast-enhanced magnetic resonance imaging of tumor-bearing mice treated with human recombinant tumor necrosis factor alpha.

Pharmacological effects of recombinant human tumor necrosis factor alpha (TNF) were studied in a mouse fibrosarcoma model using magnetic resonance imaging enhanced with a macromolecular contrast agent, albumin(gadolinium-diethylenetriamine pentaacetic acid)35. TNF was administered i.v. in a dose of 150 micrograms/kg, 60 to 80 min prior to imaging. Contrast-enhanced and nonenhanced magnetic resonance images of TNF-treated (n = 10) and untreated (n = 8) Meth A fibrosarcomas were obtained at 2.0 Tesla using T1-weighted spin-echo pulse sequences. Serial images spanning an interval of 60 to 120 min after TNF administration showed that the TNF-treated tumors enhanced significantly more overall than did untreated tumors (43% versus 31%). The most marked differential tumor enhancement was observed in the tumor rim (59% versus 40%). Nontumorous tissue, including muscle and brain, revealed no significant enhancement differences between TNF-treated animals and controls. The observed tumor enhancement corresponded strongly with Evans blue staining; the TNF-treated tumors stained deep blue, while untreated tumors and normal tissues observed did not stain. The different enhancement and Evans blue staining patterns between TNF-treated tumors and untreated tumors are attributed to TNF-induced changes in tumor capillary integrity. The data indicate that TNF effects on tumors include an increased capillary permeability for macromolecules at early times after administration. The ability to detect changes in capillary permeability in vivo using contrast-enhanced magnetic resonance imaging may prove to be clinically useful to monitor tumor response to TNF.