Harald Steinhoff

Computer assisted tomography in primary malignant lymphomas of the brain.

Computer assisted tomography (CAT) data from 10 patients with histologically verified primary malignant lymphomas of the brain are reported. Studies both prior to and after contrast medium administration were done on nine patients. In all these patients, tumor nodules presented with slightly increased density in the precontrast scan and considerable contrast enhancement. The appearance of malignant lymphomas in the CAT scan may be similar to that of meningiomas. Pituitary adenoma, medulloblastoma, and metastasis of malignant melanoma may not be ruled out in a particular case from the CAT picture alone. Blurred margin of the tumor after contrast enhancement was found in half the patients. Diffusely growing malignant lymphomas produce low density areas in the CAT scan without contrast medium uptake.

Sensitivity of Computed Tomography and Serial Scintigraphy in Cerebrovascular Disease

Computed tomography and serial scintigraphy with 99mTc-pertechnetate (radionuclide angiography and early and late static imaging) were compared in 214 patients with cerebrovascular disease. CT correctly identified 151 (95.0%) of 159 patients with completed ischemic stroke but was positive in only 11 (25%) of 44 patients with asymptomatic stenosis, transient ischemic attacks (TIA), or prolonged reversible ischemic neurological deficit (PRIND). Scintigraphy was positive in 93.1% of patients with completed stroke. CT detected 175 territories of vascular supply involved, scintigraphy 164. In patients with asymptomatic stenosis, TIA, or PRIND, scintigraphy was correct in 77.3% of cases. The combined evaluation offered a sensitivity of 97.5% in patients with completed stroke and 86.4% in those with asymptomatic stenosis, TIA, or PRIND. The rate of true-positive scintigraphic findings in patients with completed stroke did not change as the interval between ictus and study increased. In patients with intracerebral hematoma, CT was far more specific than scintigraphy. If cerebrovascular disease is suspected, radionuclide angiography should be performed first.

Diagnosis and Follow-up Studies in Cerebral Infarcts

CT is the first method of examination that enables exact differential diagnosis of the cerebral infarct. The CT image alone allows differen-tiation between ischemic infarct and hemorrhage. The aim of our in-vestigation was to analyze development and regression of the ischemic infarct and to work out diagnostic and differential diagnostic criteria.

Classification of Intracranial Tumors

L. Bruns (1914) stated in Krause’s “General Neurosurgery” that brain tumors included all neoplasms growing within the cranial cavity and that these might be divided into three groups: (1) genuine tumors, (2) granulomatous lesions, and (3) parasites. Current use of the term “brain tumor” is more precise and limited to the first of L. Bruns’ categories. Even so, brain tumors represent a large and inhomoge-neous group. The comparison and evaluation of such a diverse set of observations is only possible after making a systematic classification of pertinent data.

Computertomographie bei nicht tumorbedingten raumfordernden intrakraniellen Prozessen

Zahlreiche, nicht tumorbedingte raumfordernde intrakranielle Prozesse fuhren computertomo-graphisch zu tumorahnlichen Bildern. Die tumorspezifische Diagnose ist in vielen Fallen allein aus dem Computertomogramm kaum zu stellen. Selbst wenn alle klinischen Befunde bei der Beurteilung eines computertomogra-phischen Bildes herangezogen werden, konnen Fehlinterpretationen unterlaufen. Gerade im Hinblick auf die Indikation zu einem neurochirurgischen Eingriff und die Wahl des Operationsverfahrens ist aber eine moglichst exakte praoperative Artdiagnose erforderlich. Im Einzelfall mus also das gesamte Repertoire der klassischen Neuroradiologie ausgeschopft werden, um im Zusammenhang mit dem klinischen Krankheitsbild einen pathologischen computer-tomographischen Befund richtig einordnen und die entsprechenden therapeutischen Konsequenzen ziehen zu konnen.

Computertomographie bei Prozessen im Bereich der Schädelbasis und der Schädelkalotte

Zahlreiche CT-Scanner erlauben das Studium der knochernen Strukturen der Schadelbasis und der Schadelkalotte. Durch Wegfall einer Wasserbox und Vergroserung der Offnung der Gantry ist heute eine freie Lagerung des Kopfes des Patienten und damit die Abtastung sehr tiefer Schadelschichten ebenso wie eine coronare Schnittfuhrung moglich. Durch eine hochauflosende Matrix (z.B. 320 x 320 bei dem fur die meisten hier gezeigten Untersuchungen verwendeten CT-Scanner EMI 5005) wird ein sehr prazises Bild erzeugt.

Technique of CT Examination

The three study groups used the same CT systems during the investigation period : the EMI Mark I head scanner from 1975 until June 1977 and the EMI CT 1010 head scanner from the middle of 1977, with the Diagnostic Enhancement Package since March 1980. Special studies of the base of the skull were performed with an EMI CT 5005 body scanner (Department of Radiology, Klinikum Steglitz, Free Universityof Berlin).

Computed Tomography in Processes at the Base of the Skull and in the Skull Vault

Many CT systems allow detailed examination of the bony structures of the base of the skull and the vault. Elimination of the waterbox and enlargement of the opening of the gantry allows free positioning of the head, use of coronary projections, and studies of the base of the skull. A high-resolution matrix (320 × 320 for the EMI 5005 used in most of the studies in our series) provides a high degree of accuracy. A number of authors has reported on the use of computed tomography in studying the base of the skull, especially for planning surgical proce duresor radiation therapy (Liliequist and Forsell 1976; Bradac et al. 1977 b; Bradac et al. 1977c; Bradac et al. 1978; Hammerschlag et al. 1977; Caille et al. 1977; Lohkamp and Claussen 1977; Becker et al. 1978; Weinsteinet al. 1978; Huk and Schiefer 1978). The value and limitations of this technique in the diagnosis of lesions at the base of the skull and in the skull vault will be described in this chapter. Detailed discussions of individual histological tumor types are to be found under the appropriate headings elsewhere in the book.

Computed Tomography in Orbital Lesions

Lesions in the orbits are characterized by unilateral or bilateral proptosis and/or disorders of ocular motion. Before the advent of computed tomography diagnosis was made on the basis of conventional radiological studies of the skull and the orbits as well as with ultrasonog-raphy, fluorescence angiography, phlebography of the ophthalmic vein, and arteriograms of the internal and external carotid arteries. The introduction of CT has brought about a correspondingdecline in the use of invasive procedures (Wende et al. 1977).

Computertomographie bei Orbitaprozessen

Fur die Diagnostik von Orbitaerkrankungen, die durch einen ein- oder doppelseitigen Exophthalmus und/oder Storungen der Bulbusmotili-tat in Erscheinung treten, standen bisher neben den Rontgenaufnahmen des Schadels und der Orbita die Ultraschalluntersuchung, die Fluo-reszenzangiographie, die Angiographie der A. carotis interna und externa und schlieslich die Ophthalmica-Venographie zur Verfugung. Die Einfuhrung der CT hat die Bedeutung der invasiven Untersuchungsmethoden jedoch deutlich eingeschrankt (Wende et al. 1977).