Computed tomography with the EMI scanner in the diagnosis of primary and metastatic intracranial neoplasms

Advances in translational imaging of the microcirculation

The past few decades have seen an explosion in the development and use of methods for imaging the human microcirculation during health and disease. The confluence of innovative imaging technologies, affordable computing power, and economies of scale have ushered in a new era of "translational" imaging that permit us to peer into blood vessels of various organs in the human body. These imaging techniques include near-infrared spectroscopy (NIRS), positron emission tomography (PET), and magnetic resonance imaging (MRI) that are sensitive to microvascular-derived signals, as well as computed tomography (CT), optical imaging, and ultrasound (US) imaging that are capable of directly acquiring images at, or close to microvascular spatial resolution. Collectively, these imaging modalities enable us to characterize the morphological and functional changes in a tissue's microcirculation that are known to accompany the initiation and progression of numerous pathologies. Although there have been significant advances for imaging the microcirculation in preclinical models, this review focuses on developments in the assessment of the microcirculation in patients with optical imaging, NIRS, PET, US, MRI, and CT, to name a few. The goal of this review is to serve as a springboard for exploring the burgeoning role of translational imaging technologies for interrogating the structural and functional status of the microcirculation in humans, and highlight the breadth of current clinical applications. Making the human microcirculation "visible" in vivo to clinicians and researchers alike will facilitate bench-to-bedside discoveries and enhance the diagnosis and management of disease.

History and evolution of brain tumor imaging: insights through radiology

This review recounts the history of brain tumor diagnosis from antiquity to the present and, indirectly, the history of neuroradiology. Imaging of the brain has from the beginning held an enormous interest because of the inherent difficulty of this endeavor due to the presence of the skull. Because of this, most techniques when newly developed have always been used in neuroradiology and, although some have proved to be inappropriate for this purpose, many were easily incorporated into the specialty. The first major advance in modern neuroimaging was contrast agent-enhanced computed tomography, which permitted accurate anatomic localization of brain tumors and, by virtue of contrast enhancement, malignant ones. The most important advances in neuroimaging occurred with the development of magnetic resonance imaging and diffusion-weighted sequences that allowed an indirect estimation of tumor cellularity; this was further refined by the development of perfusion and permeability mapping. From its beginnings with indirect and purely anatomic imaging techniques, neuroradiology now uses a combination of anatomic and physiologic techniques that will play a critical role in biologic tumor imaging and radiologic genomics.

An overview of PET neuroimaging

Over the past 35 years or so, PET brain imaging has allowed powerful and unique insights into brain function under normal conditions and in disease states. Initially, as PET instrumentation continued to develop, studies were focused on brain perfusion and glucose metabolism. This permitted refinement of brain imaging for important, non-oncologic clinical indications. The ability of PET to not only provide spatial localization of metabolic changes but also to accurately and consistently quantify their distribution proved valuable for applications in the clinical setting. Specifically, glucose metabolism brain imaging using (F-18) fluorodeoxyglucose continues to be invaluable for evaluating patients with intractable seizures for identifying seizure foci and operative planning. Cerebral glucose metabolism also contributes to diagnosis of neurodegenerative diseases that cause dementia. Alzheimer disease, dementia with Lewy bodies, and the several variants of frontotemporal lobar degeneration have differing typical patterns of hypometabolism. In Alzheimer disease, hypometabolism has furthermore been associated with poorer cognitive performance and ensuing cognitive and functional decline. As the field of radiochemistry evolved, novel radioligands including radiolabeled flumazenil, dopamine transporter ligands, nicotine receptor ligands, and others have allowed for further understanding of molecular changes in the brain associated with various diseases. Recently, PET brain imaging reached another milestone with the approval of (F-18) florbetapir imaging by the United States Federal Drug Administration for detection of amyloid plaque accumulation in brain, the major histopathologic hallmark of Alzheimer disease, and efforts have been made to define the clinical role of this imaging agent in the setting of the currently limited treatment options. Hopefully, this represents the first of many new radiopharmaceuticals that would allow improved diagnostic and prognostic information in these and other clinical applications, including Parkinson disease and traumatic brain injury.

Optimized scintigraphic evaluation of infection and inflammation: role of single-photon emission computed tomography/computed tomography fusion imaging

Gallium-67 citrate and radiolabeled white blood cells have become standard inflammation/infection-seeking agents whereas other agents, such as (99m)Tc diphosphonates, commonly are used to infer an infectious process. These radiopharmaceuticals reflect physiologic and pathologic function rather than anatomical abnormality. In the clinical setting, it is often necessary to correlate these functional studies with anatomical imaging. The advent of single-photon emission computed tomography, as well as positron emission tomography, provides tomographic images for direct correlation to anatomic modalities such as computed tomography and magnetic resonance imaging. The methods by which these functional and anatomic imaging modalities are correlated include side-by-side, software, and hardware fusion. Clinically, fusion imaging has been applied primarily to oncologic and neurologic applications. The literature supports the premise that multimodality fusion would increase the specificity of the physiologic modality and increase the sensitivity of the anatomic modality. Our institution uses software fusion to aid in the diagnosis of infection and inflammation. Through case vignettes, we illustrate applications for single-photon emission computed tomography/computed tomography fusion for the diagnosis of infection and inflammation in multiple organ systems.

The initial impact of computed tomography on mortality attributed to brain tumor

The exponential growth in the number of computed tomography scanners in the United States between 1975 and 1977 was associated with a transient increase (11.9 and 14.4% for men and women, respectively) in annual crude mortality rates for primary malignant brain tumor from 1976 through 1978. This transient increase in mortality appears to have been an artifactual epiphenomenon associated with the introduction of a new technology.

Meningiomas of the clivus and apical petrous bone. Report of 35 cases

Between March, 1966, and June, 1985, 23 women and 12 men underwent partial or total resection of apical petrous or clivus meningiomas at The National Hospital for Nervous Diseases. Presenting symptoms were typically of long duration (mean 29 months) and consisted primarily of gait disturbance, headache, hearing loss, and facial pain. Cranial nerve deficits, especially affecting the fifth, seventh, and eighth nerves. were observed in nearly every patient. Tumor size, but not location, was generally associated with degree of preoperative disability. Plain skull films were usually unremarkable, but computerized tomography (CT) proved highly accurate in determining tumor location and size. A characteristic pattern of vascular displacement was seen on vertebral angiograms, although blood supply to the tumors was derived primarily from branches of the internal and external carotid arteries. Subtotal or total resection was undertaken in all cases; nine patients required adjunctive cerebrospinal fluid shunting procedures. Although surgical techniques evolved during the course of the 20-year study, a combined supra- and infratentorial approach proved a relatively safe and effective means of surgical treatment. New or worsened postoperative deficits, especially cranial nerve palsies, and complications in the immediate postoperative period frequently resulted in temporary deterioration of the clinical status during this period; the total operative mortality rate was 9%. Follow-up periods ranged up to 9 years; 70% of patients resumed an independent existence, and none is known to have required subsequent tumor surgery. The size of the lesion was the only significant factor in determining outcome. These data suggest that meningiomas of the clivus and apical petrous bone can be accurately diagnosed by CT and three-vessel angiography, and effectively treated by microsurgical resection.

Role of the CT scanner in the management of cancer

Although the diagnostic scope of computed tomography has widened considerably in recent years, assessment of patients with suspected or known malignant disease remains the major reason for body CT referrals in the United Kingdom. This paper sets out to define important advantages and limitations of CT in cancer diagnosis, addressing the topics of primary diagnosis, staging, and patient follow up. There is relatively little information on the influence of CT on patient management in oncology but reported studies indicate that CT directly alters clinical decisions in 14-30% of patients. This aspect requires further evaluation and is of particular relevance when considering the appropriate use of high cost technology.

Evaluation of the suprasellar cistern by computed tomography

The normal suprasellar cistern is a five- or six-pointed, starshaped, fluid-filled structure as demonstrated by computerized axial tomography (CAT). At various levels the normal suprasellar cistern contains the major intracranial vessels and their anastomotic channels, the optic nerves, chiasm, and infundibular stalk. The existence of lesions, either intrinsic structures of or extrinsic structures contiguous to the suprasellar cistern can be detected by their effect on the normal anatomy of the suprasellar cistern or by filling defects produced when studied with metrizamide cisternography.

A case of cystic meningioma mimicking an astrocytoma

In a 25-year-old woman, suddenly complaining of irritation and soon after of paretic symptoms in the right upper limb, a CT scan showed a large cystic mass in the left parietal lobe. As cerebral angiography was not helpful, a cystic astrocytoma was suspected. After total surgical removal of the cyst, the histological examination revealed, to our surprise, a syncytial meningioma. The rate cases of similar cystic meningioma reported in the literature are reviewed and the usefulness of biopsy on every suspected cerebral neoplasm is stressed.

CT of irradiated solid tumor metastases to the brain

Twenty patients with solid tumor metastases to the brain, demonstrated by CT scanning, had follow-up scans after radiation therapy of the metastatic focus. Nine patients (45%) showed no evidence of the metastasis on the initial follow-up scans. Another 10 patients (50%) showed some improvement in the size, enhancement, or surrounding edema of the lesion. Only one patient showed progression in spite of therapy. The CT scan identified those patients who achieved longer survival and/or longer time intervals before brain relapse. However, CT scans must be interpreted with caution in patients still on corticosteroid treatment. Additionally, other non-tumoral conditions may mimic tumor recurrence. Radiation therapy offered palliation in patients with brain metastases, and in some instances, sterilized patients of their metastatic brain involvement.

Discrepancies between radionuclide and computed tomographic scans in detecting secondary neoplastic involvement of the brain

A radionuclide (RN) brain scan and a computed tomographic (CT) brain scan were performed on the same patient within one month on 207 occasions between February 1978 and October 1979 in order to investigate secondary neoplastic involvement of either metastatic or lymphomatous nature. The two scans were read independently of each other. There was a significant difference between the results of the two techniques in 26 of the 207 cases (13%). In 15 cases, the RN brain scan found clinically suspected secondary neoplastic involvement that was not detected by CT. In the other 11 cases, lesions detected by CT were not detected with the RN scan. Discrepancies were more frequent in patients with lymphoma than in patients with carcinoma.

[Intracerebral hematoma in metastatic tumors: report of 11 cases]

Spontaneous intracerebral haematoma caused by metastatic neoplasms are reported in 11 patients, 8 males and 3 females, with age between 19 and 74 years. We had 7 melanomas, 3 carcinomas and one choriocarcinoma. The presenting symptoms were those of classical spontaneous intracerebral hemorrhage with a history of sudden headache, coma or stupor, hemiparesis or hemiplegia or other focal signal, and bloody cerebrospinal fluid. Three patients presented more than one hemorrhagic episodes. In four cases the computerized tomography revealed multiple lesions. Seven patients were operated by large craniotomy with evacuation of the hematoma and in one a cerebral biopsy revealed a melanoma and in the other six a large tumoral mass was removed. The average survival was 39 days.

Epilepsy in adults

The past decade has seen advances in the management of patients with epilepsy. The development of practical long-term electroencephalographic techniques, with or without simultaneous video recording, has increased the accuracy of diagnosis of seizure types. The technique also provides clinicians and investigators with a method for establishing the clinical efficacy of antiepileptic drugs and determining their therapeutic serum concentrations. Computerized tomography has enhanced the identification of structural brain lesions. Most of the reported CT abnormalities consist of diffuse and focal atrophies, mild ventricular dilatations, and porencephalies. CT has detected tumors in 8 to 10% of the patients regardless of age or type of seizure involved. New concepts of antiepileptic drug therapy have developed from the recognition of pharmacological properties peculiar to each agent. Determination of serum antiepileptic drug levels has to be utilized to reduce the problem of pharmacokinetic variability from one patient to another and in the same patient at different times, so that dosage can be individualized to achieve maximum therapeutic effects with least toxicity. Review of the literature on pregnancy in epileptic women shows that a third to half experienced more seizures during gestation. Reduced serum levels of most antiepileptic drugs have recently been observed during gestation. Infants of epileptic women taking antiepileptic drugs have a two to three times greater risk for congenital anomalies than infants of nonepileptic women. However, with the exception of oxazolidinediones, evidence to date has not proved the teratogenicity of antiepileptic drugs. The role of genetic factors and the effect of seizures during pregnancy have not been determined. Modest progress has been made in epilepsy rehabilitation, but serious problems still remain. The unemployment rate of persons with epilepsy is twice the national average. Half of those who are successfully employed did not disclose their disorder at the time of employment. Several prognostic indicators have been reported, but the validity of many of these indicators is questionable. For example, does shorter life expectancy apply to all subgroups, or does it vary according to seizure type and cause? The life expectancy, treatment response, and probability of remission in epileptic persons must be reevaluated after consistent applications of current methods of epilepsy management.

Tumeurs Cerebrales de l'enfant en milieu Canadien-Francais

Between 1964 and 1976, we have seen 197 cases of cerebral tumors in children. We have studied the frequency of each histological group of tumors, their localization, the results of the clinical investigation, their clinical manifestations and the prognosis for each group.

This study has confirmed that in children brain tumors are more frequently localized in the posterior fossa (56.4%). As in other series, tumors derived from the glia represent nearly 80% of the total. Clinically, increased intra-cranial pressure is the most frequent manifestation of posterior fossa lesion (75% of cases) while cerebellar involvement was seen in 60% of these childdren. Brain stem lesions and supratentorial tumors are more insidious in their presentation and their clinical manifestations more diversified.

The EEG appeared useful in the investigation of brain tumors and showed irregularities in 78% of our patients. However, a more specific diagnosis required more invasive techniques such as angiography, pneumoencephalography or ventriculography.

As in previous series, the mortality rate remained high in the children we have followed, particularly for some groups of tumors (glioblastoma, medulloblastoma, brain stem lesions). It is to be hoped that with the introduction of the CT Scan, the improvement of neurosurgical techniques and the use of immuno and chemotherapy, the prognosis may be improved.

Diagnosis of acoustic neuroma with computed tomography

Sixty-one acoustic neuromas were examined with computed tomography (CT). For differential diagnosis the tumors were thoroughly analyzed for manner of growth, shape, volume, calcification, attenuation pattern, constrast enhancement, presence of peripheral edema, and cisternal deformation.

Computerized tomography or paranasal sinus neoplasms

Computerized tomography represents a new and valuable diagnostic tool to the otolaryngologist and head and neck surgeon in several ever-increasing aspects of his clinical practice. This report presents CT scans utilizing the E.M.I 5005 body scanner on patients with neoplasms of the paranasal sinuses presenting to the Head and Neck Service of The University of Texas System Center M. D. Anderson Hospital and Tumor Institute. Only patients undergoing surgical resection of such lesions are included so that actual operative and surgical pathological findings can be used for critical comparison of diagnostic information derived from polytomography and computerized tomography. Seven illustrative cases are presented. In general, computerized tomography has been found to be equal to polytomography in assessing bone destruction or involvement by tumor, and superior to polytomography in determining accurately the soft tissue extent of disease. CT scanning, however, has been found to have limitations in the delineation of soft tissue disease in areas of high contrast in tissue density, and in the evaluation of possible intracranial tumor extension in isodense, avascular lesions.

Contrast enhancement of cranial lesions in computed tomography

The time course of enhancement in apparently normal brain tissue, edema and focal lesions during 30 to 60 min after intravenous injection of vascular contrast medium was evaluated in a series of 41 patients with different intracranial lesions. The attenuation of apparently normal unenhanced brain tissue varied with the level of the scan, mainly an effect of beam hardening. Different types of enhancement response are discussed in terms of a 3-compartment model. The differential diagnostic potential of contrast enhancement in the early phase needs further evaluation using instruments with short scanning time, while the late phase of enhancement must be recorded with the use of a reliable head fixation to provide reproducibility of repeat measurements.

The reliability of computer tomography for the diagnosis and differential diagnosis of meningiomas, gliomas, and brain metastases

The CT characteristics were studied in a series of 90 tumours, and the diagnostic criteria were determined for meningiomas glioblastomas, other gliomas and metastases. These criteria were then employed in another group of 46 tumours in which the histological diagnosis was not known at the time of examination. The over-all diagnostic accuracy was 85%, and it was largely the same for the various sub-groups. Careful combination of the CT characteristics, perfect techniques, and increased experience may further improve the diagnostic accuracy.

Radionuclide brain imaging--its role and relation to CT scanning

Separate CNS disease entities are discussed with either the complementary or exclusive indications for radionuclide brain imaging and computerized cranial tomography. Either modality alone has a potential overall precision somewhat in excess of 90% in the localization of cerebral lesions with the effectiveness of each modality differing according to the histology and anatomic location of the lesion. Most investigators agree that the combined application of the two procedures is far superior to their separate use. Routine dynamic isotope studies are essential and in addition, new radiopharmaceuticals and technological advances may improve the radionuclide evaluation of CNS disease. Areas discussed include: primary and secondary CNS neoplasms; acute cerebrovascular accidents; arteriovenous malformations; traumatic cerebrovascular disease; hydrocephalus and dementia; and intracranial inflammatory processes.

[The diagnostic value of CT and angiography in cerebral tumors (author's transl)]

In a cooperative study the examination results of CT and angiography of 756 patients with verified supratentorial tumors were compared. CT displayed the higher diagnostic accuracy. Temporobasal tumors cause diagnostic problems for both examination methods. The value of arteriography is still unquestioned because using this examination method the differential diagnosis of mass lesions can be considered largely secured.

Computed tomography of supratentorial meningioma

The appearance on C.T. of 28 meningiomas is described. On the plain scan they presented as a rounded, well defined lesion with a high density in 18 cases and a density equal to or lower than brain tissue in 10 cases. The density could be related to certain histologic features as the amount of connective tissue and extracellular water and the presence of psammoma bodies or lipid storage cells. After administration of contrast a homogeneous, markedly increased, sharply marginated density was seen in most meningiomas. Contrast enhancement appeared to be dependent on the vascularity of the tumour. +/- 50% of the cases demonstrated edema grade II or III. On first interpretation 93% of the meningiomas were recognized as a lesion and a tumour (2 false negative) and 79% as a meningioma (2 false negative and 4 incorrect). Only one false positive C.T. scan was encountered. As a screening method R.N. scanning has about the same accuracy as C.T.; in establishing a definite diagnosis angiography equals C.T.; but C.T. is superior as it combines the diagnostic qualities of both methods.

Computed tomography of supratentorial astrocytoma

In a group of 40 astrocytomas the C.T. appearance was correlated with the grade of malignancy. On the plain scan the majority presented an irregular, nonhomogeneous low density lesion, better demarcatable in high than in low grade astrocytomas. Contrast enhancement was seen in 28 of the 32 high grade astrocytomas, 50% of the annular, 25% of the nodular and 25% of the mixed type. Six of the 8 low grade astrocytomas showed no contrast enhancement and 1 showed an annular type lesion. A relationship was found between the degree of contrast enhancement and the vascularity. Mass effect was observed in all but 1 patient, but more pronounced in high grade astrocytomas. At the first interpretation 98% were recognized as a lesion, 93% as a tumor and 68% as an astrocytoma. One false negative and no false postive C.T.scans were obtained. In review, high and low grade malignancies were correctly differentiated in 90%. As a screening method, the combination of EEG and echo equalled C.T.; in establishing a definite diagnosis angiography was inferior to C.T. Solely on the basis of the C.T. appearance, astrocytomas can hardly be differentiated from the other malignant brain tumors, but the grade of malignancy can be predicted reliably.

Computerized tomography as a possible aid to histological grading of supratentorial gliomas

Computerized tomography (CT) is known to be very helpful in demostrating the presence and extent of supratentorial gliomas, practically in combination with intravenous injection of contrast material. Certain specific density patterns were found to exist and enabled us to differentiate with confidence the low-grade gliomas from the glioblastomas. Overlapping did occur, however, as was to be expected, since histological proof was sometimes obtained by the needle biopsy with its inherent doubt as to true tumor representation. Future CT techniques such as sequential scanning after intravenous injection of contrast material may further increase the usefulness of CT scans in the diagnosis and therapeutic approach to the patient with a suspected glioma.

The clinical efficacy and cost analysis of cranial computed tomography and the radionuclide brain scan

Cranial computed tomography (CCT) has already been demonstrated to provide significant diagnostic information in patients with neurologic disease and to reduce the need for special neuroradiologic procedures. The important question remaining is: Should CCT replace the radionuclide brain scan (RBS) as the first diagnostic study in most patients with suspected intracranial pathology? Data are now available to define the costs and benefits of this substitution. The technical costs of CCT have been determined by a national survey and have shown to be $130 per patient at a volume of 50 patients per week. The costs of RBS at the Mallinckrodt Institute have been estimated at $51 per patient. Data from the literature indicate that CCT is slightly more sensitive and considerably more accurate than RBS. Eighteen to twenty-eight percent of patients studied by CCT and RBS have abnormalities (e.g. cerebral atrophy and ventricular dilatation) that are only detected by CCT, and the overall accuracy of CCT is 95%, while the accuracy of RBS is approximately 70%. Substituting CCT for RBS is cost-beneficial. Although CCT is more costly, it increases overall accuracy by approximately 25%. The cost benefit is further increased by the reduction of complicated diagnostic procedures (and associated hospitalization and morbidity) and improvement in diagnostic information for the individual patient. Substituting CCT for RBS may not be more costly because a positive RBS will be followed by CCT (because of increased diagnostic information), and a negative RBS may be followed by CCT (because of increased accuracy), whereas a positive or negative CCT is unlikely to be followed by RBS.

The complementary role of computerized axial transmission tomography and radionuclide imaging of the brain

Computerized axial transmission tomography and radionuclide imaging are complementary procedures, and the following recommendations are made as to their use. Where there is no real clinical suspicion of intracranial disease, either modality can be used for "rule out" screening; the choice can frequently be made on the basis of which modality is cheaper or more quickly available. It should be remembered that "quicker" is often "cheaper". Total cost is determined, not only by the cost of the procedure, but also the per diem costs incurred in waiting for that procedure. Thus the more expensive modality may, in effect, be cheaper if delays are shorter. Screening of the elderly patient, particularly when atrophy or communicating hydrocephalus is of clinical concern, should be by the CT method because of its ability to visualize cerebrospinal fluid spaces. When clinical signs and symptoms point to intracranial abnormality, both modalities should be utilized. If either study done first is normal, use of the other modality is mandatory. When the first study is positive with pathognomonic findings for a specific disease, which totally explains the patient's neurologic problems, the second study need not be employed. Such examples might include the fresh cerebral hemorrhage demonstrated by CT imaging, the AV malformation defined by dynamic-static radionuclide imaging, or multifocal metastatic lesions defined by either. However, when the clinical picture is not totally and satisfactorily explained by the demonstrated disease, the other modality should also be employed. Under many circumstances, neither study will be so reliable, specific, and free of false-negative or false-positive findings as to warrant ignoring the additional information potentially available from the other study.

Computerized cranial tomography and radionuclide imaging in the detection of intracranial mass lesions

Computerized cranial tomography (CCT) and radionuclide imaging (RI) of the brain are both accurate techniques for detecting intracranial mass lesions. CCT is superior in detecting low-grade gliomas, cystic lesions, parasellar tumors, and brain stem lesions. Overall, CCT detection rates are slightly higher than those with RI, but the use of iodinated contrast media with CCT increases the risk of this examination. There is a significant difference in the generally binary (positive/negative) type of information offered by RI and the more specific information offered by CCT about the pathologic nature of a lesion and its precise location. In the evaluation of patients with suspected intracranial mass lesions, CCT is generally the preferable initial diagnostic test. However, RI may still serve as a satisfactory screening examination in certain well-defined clinical situations.

Impact of computerised axial tomography of the management of posterior fossa tumours in childhood

Computerised axial tomography (CAT) has profoundly altered the management of most children with posterior fossa tumours. Fifty such children were operated on from October 1973 to December 1975, 20 of whom were explored after investigation by CAT only. Most recent experience suggests that CAT need by the only investigation in the majority of children suspected of having an expanding lesion in the posterior fossa.

Priorities and indications of computed tomography in clinical practice

Because of its technical capabilities, its rapidity and its non-invasive nature, computed tomography (CT) has given a new scope to neurological diagnosis and to the understanding of various aspects of neurological science. The availability of this test is determined by the patient load. If precise clinical indications are not considered, patients requiring CT the most may be denied immediate examination because less urgent cases may be occupying valuable diagnostic time. Moreover, the test is relatively expensive for the individual patient and for the community; this presents another facet of its use that should be taken into account. The technical limitations and clinical priorities to be considered when a physician is entertaining this test for a patient have been outlined. The indications have been divided into absolute and relative, according to the degree of clinical urgency. As a result, a priority guideline for diagnostic CT has been provided.

Computer tomography of cerebellopontine angle lesions

Computer tomography (CT) was used in 53 consecutive patients with a working diagnosis of cerebellopontine angle tumor. The CT was performed with the 160 X 160 matrix scanner, height of sections was 13 mm. Metrizoate sodium (1.5 ml/kg of body weight) was used for tumor enhancement. Seventeen CT scans revealed tumors; one patient proved at operation to be false-positive. Thirty-six CT scans revealed no tumors; two examinations may prove to be false-negative, but surgical verification has so far not been obtained. The smallest tumor demonstrated by CT extended 7 mm into the angle, while one of the possible false-negative CT scans after iophendylate injection cisternography showed a tumor extending 5 mm into the angle. It is concluded that CT is a harmless, noninvasive neuroradiological procedure, and should precede invasive procedures. It can be used safely in patients with increased intracranial pressure.

Computed tomography of cerebral infarction: hemorrhagic, contrast enhancement, and time of appearance

Large confluent petechial hemorrhages and/or hemorrhage within infarct may be seen on CT scan. Small petechial hemorrhages are not resolved by current equipment and techniques. Elevation of absorption values of an infarct following contrast media primarily occurs in the first month after onset, and may be occasionally confused with a tumor. Sequential CT changes in infarcts correlate well with established pathologic changes. Cerebral infarction may be seen on CT scan in some cases as early as 24--48 hr after its onset.

Computed tomography in the diagnosis of cerebral abscess

Computed tomography (CT) was performed 64 times on 22 patients with cerebral abcesses, using the 160 X 160 matrix EMI scanner. The diagnosis was based upon the demonstration of a localized low-attenuation area appearing, after the administration of contrast medium, as a high-attenuation annular rim ascribed to displaced and/or newly formed vessels, the so-called abscess membrane. CT is compared with the conventional diagnostic methods of neuroradiology. The differential diagnostic accuracy of CT is clearly superior to that of previous methods, including angiography, which, until now, we have considered the most accurate method.

Computed tomography of tumors of the pineal region

Eight pathologically proven cases of pineal region tumors examined by computed tomography (CT) were found upon reviewing 11,000 consecutive CT studies at the Massachusetts General Hospital. The CT scan findings of the eight cases are described and related to a pathological classification of pineal tumors.

Computer tomography in the diagnosis of cerebellopontine angle tumours

53 patients clinically suspected of having a cerebellopontine angle (CPA) lesion were examined by computer tomography (CT) with 160 X 160 matrix EMI scanner. 17 cases (32%) had tumour positive CT, of which 12 were neurinomas and 1 meningioma. 1 CT suggestive of a CPA lesion was false positive and 1 unoperated case is probably a false negative CT. Three of the eleven verified neurinomas (27%) were of the medial type originating in the angle cistern. One neurinoma protruding 1 cm into the cistern showed no contrast enhancement. 2 CT scans (3.8%) were unsatisfactory due to movements and the large size of the head. CT is valuable for the investigation of CPA pathology and the diagnostic efficiency compares favourably to other neuroradiological procedures.

[Two-dimensional ultrasonic diagnosis of brain tumors and subdural hematomas by electronic sector scanning (author's transl)]

Electronic sector scanning (ESS) is a new two-dimensional ultrasonic technique which provides continuous and instantaneous cross-sections of intracranial structures through the intact skull, including the ventricles and large cerebral arteries, by means of a stationary probe. 2. The efficiency of the ESS in the diagnosis of brain tumors and extracerebral hematomas in 295 neuroradiologically controlled cases out of an unselected number of patients during 1972-1974 is described. 3. Supratentorial brain tumors can be detected directly with the ESS by abnoramal reflections of the tumors as well as indirectly by displacement of intracranial reference structures, mainly the ventricular borders. In 239 cases of suspected brain tumor, 126 were neurodiologically confirmed as supratentorial brain tumors. Among these 126 brain tumors the correct localization was determined by the ESS in 86.5%. 4. The highest reliability of the ESS proved to be the direct demonstration of frontal tumors (93%), whereas space-occupying lesions near the midline could be shown only in 79%. Up to now there have been difficulties in the diagnosis of tumors situated near bony structures, e.g., calvarian meningiomas. 5. Subdural hematomas (56 patients) could be lateralized correctly in 93%. Hwever, direct demonstration of the border of the hematomas could be achieved only in 48,2%. Chronic subdural hematomas in children are easier to recognize and the border could be demonstrated in 18 out of 19 cases. 6. The clinical applicability and diagnostic values of the ESS as a nontraumatic investigation procedure are discussed in comparison to cerebral angiography, pneumoencephalography, brain scintigraphy, and CAT scan. scintigraphy, and CAT scan.

Computer tomography for diagnosis of intracranial tumours compared with other neuroradiologic procedures

The diagnostic effectiveness of computer tomography has been assessed in a series of 361 patients with the primary clinical problem of a possible intracranial neoplasm. Of these patients, 171 were shown to have a tumour, confirmed at microscopy in 115 instances. Computer tomography was compared with other established neuroradiologic procedures, such as encephalography, angiography and isotope scanning, all of which were frequently used in this series of patients.