Human brain tumors: spectral patterns detected with localized H-1 MR spectroscopy.

Image-guided localized proton magnetic resonance (MR) spectroscopy of intracranial tumors was performed to correlate spectral patterns and histologic findings. Thirty-six patients were examined prior to any specific treatment. Evaluation based on signal intensity ratios showed that all tumor spectra differed from spectra of healthy brain tissue.

[Experimental studies on magnetic resonance tomographic and magnetic resonance angiographic imaging of poststenotic flow patterns].

A phantom has been developed, which permits the perfusion of defined stenosis with variable flow rates. The post-stenotic flow patterns were imaged by means of conventional MRI sequences and special angiographic sequences using a 1.5 total body scanner (Gyroscan S15, Philips).

In vivo imaging of glucose consumption and lactate concentration in human gliomas.

Twenty patients with histologically confirmed gliomas were studied with positron emission tomography (PET) and proton magnetic resonance spectroscopy (1H-MRS). PET with 18F-2-fluoro-2-deoxy-D-glucose (FDG) provided tomograms of the metabolic rate of glucose. MRS images were obtained by combining volume-selective excitation with phase-encoded acquisition.

[Conventional and cine-MRT in patients with aneurysms of the abdominal aorta].

We studied 40 patients with aneurysms of the abdominal aorta by MRI. These results were compared with those obtained by real-time sonography (n = 40), angiography (n = 32) and CT (n = 16). In 30 patients the imaging results were compared--as far as possible--with the operative findings.

[Balloon-expandable stents in arterial changes of the iliac arteries. Early and follow-up results of 65 interventions].

69 balloon-expandable vascular endoprostheses (Palmaz stents) were placed in 65 iliac arteries of 57 patients. The indications for stent placement were total occlusions (n = 15), restenosis after PTA (n = 13), dissections (n = 4), post-operative strictures (n = 3) or others (n = 30). The peak systolic pressure gradient dropped from 43.

MR imaging of poststenotic flow phenomena: experimental studies.

Poststenotic flow patterns were analyzed in a flow phantom with a 1.5-T magnetic resonance (MR) imager, with use of different MR imaging and MR angiographic pulse sequences. Spin-echo, fast field-echo, two-dimensional inflow (multiple single-section technique), and flow-adjusted-gradient sequences were applied.

[Aortobronchial fistulae as late complications following the surgical correction of aortic isthmus stenosis].

Three patients (2 men, aged 39 and 52 years, one woman, aged 47 years) developed hemoptysis 3-19 years after surgical resection of coarctation of the aorta. Digital subtraction angiography in the two men was suspicious of an aortobronchial fistula. An emergency thoracotomy revealed the diagnosis in the woman: she died during the operation of intractable arterial bleeding, the initial operation having been atypical (insertion of a graft extending across the isthmus to the ascending aorta).

[Techniques, results and risks of chemoembolization of malignant liver tumors].

This is a report on 55 chemoembolizations (ChE) in 31 patients with primary (n = 10) and secondary (n = 21) liver malignomas. Probing of the segmental arteries was always possible by means of a coaxially placed 3F catheter system. Chemoembolization was effected with a mixture of ivalon particles, 20 mg mitomycin or 40-60 mg epirubicin and an ethibloc solution.

[Stents in iliac vascular changes].

The results of 79 iliac stent placements in 64 patients are reported. The technical success rate was 96%. The systolic pressure gradient dropped from 44 mmHg before to 2.

Metabolic imaging of patients with intracranial tumors: H-1 MR spectroscopic imaging and PET.

Hydrogen-1 magnetic resonance (MR) spectroscopic images of patients with intracranial tumors were obtained. Metabolite maps of N-acetyl aspartate, choline, lactate, and creatine concentrations were reconstructed with a nominal spatial resolution of 7 mm and a section thickness of 25 mm. The metabolite maps showed variations in metabolite concentrations across the tumor.

Positron emission tomography of fluorine-18-deoxyglucose and image-guided phosphorus-31 magnetic resonance spectroscopy in brain tumors.

Positron emission tomography (PET) of 2(18F)-fluoro-2-deoxy-D-glucose (FDG) and volume-selective phosphorus-31 magnetic resonance spectroscopy (31P-MRS) are methods used to assess the energy metabolism of the brain. Both methods were studied with respect to their contribution to differential diagnosis in 23 patients with various brain tumors. The various neuroectodermal tumors differed with respect to their metabolic rate for glucose (MRGL).

[Clinical value of new rapid nuclear magnetic resonance tomography in preoperative assessment of hypernephroma. A prospective comparative study of CT and MR].

The new technique of rapid magnetic resonance imaging (MRI) with a paramagnetic contrast agent provides excellent imaging of the kidneys and their lesions. MR imaging of this anatomical region at short breath holding intervals matches the well-known quality of computed tomography (CT) for the first time. MR and CT studies were performed on 36 patients with proven renal cell carcinoma.

[Renal artery stenosis: possibilities of magnetic resonance tomography].

Non-invasive detection of stenotic lesions of the renal arteries remains an important clinical problem. Recent advances in magnetic resonance angiography represent a significant progress towards achieving non-invasive diagnosis of vascular diseases. The purpose of this study was to evaluate the possibilities of assessment of renal artery stenosis with commonly available hard- and software equipment.

Adrenal masses: evaluation with fast gradient-echo MR imaging and Gd-DTPA-enhanced dynamic studies.

Fast gradient-echo magnetic resonance (MR) imaging of 38 adrenal masses with proved diagnosis was performed during suspended respiration with various repetition times (TRs), echo times (TEs), and flip angles. Dynamic perfusion studies after gadolinium diethylenetriamine-pentaacetic acid (DTPA) administration were performed by repeated imaging at short time intervals. With more T2 weighting (TR = 60 msec, TE = 30 msec, and flip angle = 15 degrees), malignant tumors and pheochromocytomas had a significantly higher relative signal intensity than adenomas; overlap of signal intensity led to equivocal findings in nine cases.

[A comparison of digital luminescence radiography and conventional radiodiagnosis in sialography].

In 25 patients sialographies were obtained by both conventional film-screen system combinations and computed radiography (CR), the digital exposure dose being 50% of the conventional one. In CR two differently post processed images were obtained from one x-ray exposure: one "conventionally" processed image resembling a conventional film-screen system combination and a complementary "enhanced" image showing a higher edge enhancement at the same spatial resolution. CR proved to be equivalent to conventional radiography despite the reduction in exposure dose.

Recurrent rectal cancer: diagnosis with MR imaging versus CT.

During an 18-month period, a prospective study comparing the findings at computed tomography (CT) and magnetic resonance (MR) imaging was conducted on 35 patients who satisfied the following criteria: prior surgery for rectal cancer (11 curative resections, 24 rectal amputations), perineal pain and/or elevated carcinoembryonic antigen (CEA) level, and a soft-tissue mass in the presacral fossa demonstrated at CT. Twenty-two patients had tumor recurrence; 13 patients had only inflammatory changes or radiation fibrosis. At a single examination of each patient (with no reference to prior baseline studies), MR imaging was more accurate than CT, largely because MR imaging was more successful in the distinction of recurrence from fibrosis based on the differences in signal intensity on T2-weighted images.

[Computerized tomography in bronchial cancers].

For the exact evaluation of central and peripheral bronchogenic carcinoma CT is a usefull method that can provide important information needed by the clinicians. CT is able to demonstrate the exact extent of the disease and thus enable the surgeon to plan surgical intervention, to assess the risk involved or to decide for inoperability.

[Extracranial congenital arteriovenous fistula in a newborn infant].

A child with a congenital arteriovenous fistula between the arteria carotis externa and sinus sigmoideus is presented. This case showed further complications by the development of congestive heart failure and a Kasabach-Merritt syndrome. By an early excision already in the neonate age after diagnosis by digital subtraction angiography, the child could be saved.

[Importance of rapid MR imaging for tumor diagnosis in the area of the kidneys and adrenals].

Gradient-echo pulse sequences with fast acquisition times permit examinations in short breath-holding intervals. In this way an improvement of MR imaging of upper abdominal organs can be expected. In 41 patients with space-occupying lesions of kidneys and adrenals, influence of external parameter variations on resulting contrasts was analyzed and results were compared to other imaging methods.

[Diagnosis of recurrent rectal cancer: Comparison of CT and MR].

For the assessment of local recurrence after surgical treatment of rectal carcinoma the results of MR and CT examinations in 29 patients were analyzed. Diagnosis was confirmed by surgery, by multiple biopsies and by follow-up examinations. CT yielded in only 11 cases clearly positive or negative findings.

[Initial experiences with gadolinium DTPA in magnetic resonance tomography of bone and soft tissue tumors].

MR was performed in 41 patients suffering from benign and malignant bone and soft-tissue tumor before and after intravenous injection of the paramagnetic agent gadolinium-DTPA (Gd-DTPA). Using T1-weighted parameters, the contrast of tumor tissue versus muscle could be increased by Gd-DTPA. Thus, extraosseous extension as well as infiltration of the spinal canal was depicted to better advantage.