Gerhard Ranner

Functional magnetic resonance imaging of human renal allografts during the post-transplant period: Preliminary observations

Graft dysfunction is a common occurrence during the first weeks following renal transplantation. The current study was designed to evaluate the potential of renal magnetic resonance (MR) perfusion imaging to differentiate acute allograft rejection (AAR) from acute tubular necrosis (ATN) during the post-transplant period. Twenty-three consecutive patients with clinically suspected ATN and/or AAR and eight consecutive control patients (asymptomatic, serum creatinine concentration < 1.5 mg/dL) underwent MR perfusion imaging of the renal allograft within 64 days after transplantation. Histopathology was obtained in all cases with clinical suspicion of ATN or AAR. Sixty sequential fast gradient-recalled-echo MR images were acquired in each patient after intravenous administration of gadolinium-DTPA (0.1 mmol/kg). Histopathology revealed 6 patients with pure AAR, 4 patients with a combination of AAR and ATN, 12 patients with ATN and 1 patient with normal findings. Kidney graft recipients with normal renal function showed a moderate increase in signal intensity (SI) of the renal cortex and medulla after administration of contrast agent followed by an immediate and short decrease in SI of the medulla (biphasic medullary enhancement pattern). The increase in cortical SI of patients with AAR was significantly smaller (61 +/- 4% increase above baseline) than that measured in normal allografts (136 +/- 9% increase above baseline) (p < 0.05) and patients with ATN (129 +/- 3% increase above baseline) (p < .05). Patients with ATN had a slightly delayed and diminished cortical enhancement and an uniphasic and lesser medullary enhancement pattern compared to that observed in normal allografts (p < 0.05). A close correlation (r = 0.72) was found between serum creatinine concentration levels and changes in SI. Thus, MR imaging results and histopathology were in agreement in 22 of 23 patients (96%). MR perfusion imaging of renal allografts can be used to noninvasively differentiate ATN from AAR during the post-transplant period, and may also be helpful in cases were covert AAR is superimposing ATN during a phase of anuria. Patients with ATN can be separated from normals in the majority of cases as reflected by an uniphasic medullary enhancement pattern.

Follow-up and quality of survival of 67 consecutive children with CNS tumors.

We report the finding at follow-up in 67 consecutive children with central nervous system tumors treated over a 5-year-period at a single institution. The diagnoses were supratentorial astrocytoma (n = 12), cerebellar astrocytoma (n = 10), ependymoma (n = 9), medulloblastoma (n = 9), brain stem glioma (n = 6), optic pathway glioma (n = 5), and others (n = 16). The survival rates were 83% for supratentorial astrocytomas at a median of 46.5 months, 90% for cerebellar astrocytomas and 55% for ependymomas at 40 months, respectively, 55% for medulloblastomas at 22 months, 33% for brain stem gliomas at 23 months, and 80% for optic pathway gliomas at 49 months. With regard to neurological sequelae, 13 patients were treated for epilepsy, 13 patients had mild to moderate neurological deficits, and 4 patients were severely disabled. Seventeen of 37 tested patients performed below average on formal neuropsychometric testing, one-fourth attended special education courses, and at least one-fourth suffered from behavioral and adjustment problems.

Endoscopic removal of an intraorbital "tumor": a vital surprise.

We present the first case report of an endoscopic removal of a living worm, species Dirofilaria repens, from the orbital cavity. As of today, over 410 cases of Dirofilaria repens infections in man are recorded in world literature, six of which were localized in the orbital cavity. In Austria we know of four cases of an infection with this parasite, but none in the orbit. Dirofilaria repens is widespread only in the Old World, particularly in Southern and Eastern Europe, in Asia Minor, and in Central and Southern Asia. The highest prevalence of the disease is recorded in Italy (181 cases). In clinical practice, the infections have mostly been misdiagnosed as a neoplasia, usually benign but sometimes malignant. Under the assumption of an intraorbital tumor, the endoscopic transnasal revision of the orbital cavity was performed, as this approach promised to be least traumatic and best suited for the lesion, resulting in complete removal of the live worm. In unclear lesions in the head and neck, an infection with Dirofilaria repens should be considered as a differential diagnosis.

MR-imaging with Gd-DTPA in carcinomas of tongue, oro- and hypopharynx

High-field MRI was performed in a series of 24 patients with squamous cell carcinomas of the tongue, oro- and hypopharynx. The value of contrast enhanced T1-weighted images in tumor staging was established prospectively. Non-contrast T1-weighted images did not provide sufficient tumor-delineation. Marked contrast enhancement produced by Gd-DTPA was observed in all carcinomas and in normal pharyngeal mucosa. In tumors of the tongue and upper pharynx clinical examination and ultrasound were equally sensitive as post-contrast MRI; in tumors of the lower pharynx the true tumor extension could be better assessed by contrast-enhanced MRI.

Scintigraphic long-term follow-up of a patient with metastatic glucagonoma.

Two years after resection of a pancreatic glucagonoma, scintigraphy with 111indium-labeled octreotide revealed hepatic metastases in a 48-yr-old man. Hepatic metastases were also visualized by CT, whereas an additional lesion in the chest was seen only by scintigraphy. A total of 11 follow-up examinations over 46 months proved somatostatin receptor scintigraphy to monitor reliably somatostatin receptor expression, growth and dissemination of glucagonoma metastases, and to indicate therapeutic readjustment if necessary. The survival time of the patient is now >75 months, in comparison with a mean survival time of 59 months reported for metastatic glucagonoma.

Bone scintigraphy and magnetic resonance imaging in adult-onset Still's disease.

Adult-onset Stills disease (AOSD) is an acute systemic inflammatory disorder of unknown origin. We report a patient whose AOSD presented with the commonly accepted diagnostic clinical signs and laboratory parameters. The painful joints distinctly demonstrated increased uptake of 99mTc-methylene diphosphonate in scintigraphy and areas of increased gadolinium-enhanced signal in MRI. Biopsies indicated bone marrow edema. AOSD in association with bone marrow edema had not been previously demonstrated. AOSD is often diagnosed after a considerable delay, bone scintigraphy, and magnetic resonance imaging may offer new imaging techniques for early diagnosis and successful therapy in follow-up examinations.

Abdominal metastases of an ovarian cancer demonstrated on bone imaging.

Tc-99m HMDP uptake by abdominal metastases of an ovarian cancer was seen on a bone image. The findings were confirmed by computed tomography and by biopsy at surgery. The psammoma bodies throughout the tumor tissue appeared to be the substrate of this unusual extraosseous tracer uptake.