W. Döhring

Classification of Severe Head Injury Based on Magnetic Resonance Imaging

SummaryObject. In 1991 a new pioneering classification of severe head injuries had been proposed, based on CT findings. Unfortunately CT cannot visualise all lesions. Especially brain stem lesions may escape CT in spite of modern equipment, but may be demonstrated by MRI. The high incidence of CT negative but MRI positive posttraumatic brain stem lesions has already been demonstrated in a limited number of cases. A statistically significant evaluation is still missing. Therefore we have investigated a series of 102 comatose patients, in whom a statistical evaluation of MRI findings and their correlation with mortality and outcome of survivors was possible. Patients and Methods. MRI was obtained within 8 days after servere head injury in 102 patients with a minimum of 24 hours of coma. The location of the lesions, identified by a neuroradiologist who was unaware of the clinical findings, was correlated with mortality, outcome of surviors and duration of coma. The correlation was analysed statistically. Follow-up ranged from 3 months to 3 years with a mean of 22 months. Four groups of lesions gave significant correlations: Grade I lesions were lesions of the hemispheres only; Grade II lesions were unilateral lesions of the brain stem at any level with or without supratentorial lesions; Grade III lesions were bilateral lesions of the mesencephalon with or without supratentorial lesions. Grade IV lesions were bilateral lesion of the pons with or without any of the foregoing lesions of lesser grades. Results. Mortality increased from 14% in grade I lesions to 100% in grade IV lesions. The Glasgow outcome score differed significantly for each grade. The mean duration of coma increased from 3 days in grade I patients to 13 days in grade III. The correlations between the lesions grade I to IV with mortality, outcome of survivors and duration of coma were highly significant. Conclusion. The statistically significant correlations between the 4 groups of severe head injury patients, as identified by MRI, with mortality and outcome of survivors justify a new classification based on early MRI findings.

Brain stem lesions after head injury.

Abstract There is little knowledge on the morphology of the brain stem in survivors of head injury, as CT fails to show brain stem lesions, and neuropathological data is only available from autopsies. As magnetic resonance imaging (MRI) sheds new light on morphological lesions of the brain, the authors investigated 100 patients with a severe head injury. MRI was performed in a prospective study within the first seven days after head injury while the patients were still in coma and on ventilation. Relating the location of the lesions as depicted by MRI with the initial CT scan and outcome, death appeared to be closely linked to the phenomenon of bilateral pontine lesions. The extent of supratentorial lesions had no bearing on survival at all in the absence of brain stem lesions. Altogether the brain stem was affected in 52%. Obviously the occurrence of bilateral upper pontine lesions is of highest predictive value for a fatal outcome. Severe destruction of supratentorial white matter as demonstrated by MRI is not related to increased mortality, as long as the brain stem is spared. [Neurol Res 2002; 24: 145-146]

Digital selenium radiography: detection of subtle pulmonary lesions on images acquired with and without an additional antiscatter grid

OBJECTIVE the objective of this ROC-study was to evaluate the diagnostic efficacy of images acquired with a grid in digital selenium radiography compared to that on images obtained with the integrated air gap only. MATERIALS AND METHODS seven types of simulated lesions were superimposed onto an anthropomorphic chest phantom. Selenium radiography images were obtained either with or without an additional antiscatter grid. For images acquired with a grid either a similar or increased exposure level was used. Both normal and obese patients were simulated. RESULTS When a grid was used with an equivalent detector dose and a higher exposure, diagnostic performance was significantly improved as compared to images obtained with only the air gap. ROC curve areas for mediastinal nodules and catheters were substantially higher for images acquired with a grid and the same exposure level compared to images obtained without a grid. However, detection of linear, net-shaped and reticulonodular structures in peripheral lung regions was significantly worse when a grid was used with an equivalent exposure level. Concerning the interpretation of images obtained from the normal and obese phantom models, no substantial differences were observed. CONCLUSION a marked improvement in diagnostic performance could be achieved by means of the use of an additional antiscatter grid and an equivalent detector dose. However, when the same exposure was used, images acquired with the grid allowed a better detection of mediastinal structures although a worse performance was evident in radiolucent lung regions. Therefore, the routine use of a grid without increased exposure is not recommended.

Neuroradiologische Befunde zur Beurteilung der Prognose bei Patienten nach Schädel-Hirn-Traumen

ZusammenfassungZiel: In der vorliegenden Untersuchung sollte die prognostische Wertigkeit von neuroradiologischen Befunden in der Computertomographie (CT) und der Magnetresonanztomographie (MRT) bei Patienten mit einem Schädel-Hirn-Trauma (SHT) in Bezug auf die Prognose verglichen werden. Patienten und Methoden: Untersucht wurden 100 Patienten nach einem SHT, die mindestens 24 Stunden bewusstlos waren. Es wurden die Komadauer und das Behandlungsergebnis mittels der Glasgow Outcome Scale (GOS) registriert. Ausgewertet wurden die primären zerebralen CT-Untersuchungen vom Unfalltag und MRT-Untersuchungen, die im Mittel 5 Tage nach dem SHT erfolgten. Ergebnisse: Die engsten Korrelationen zum GOS fanden sich mit − 0,711 (p = 0,01) für die Hirnstammläsionen im MRT. Im CT fanden sich geringe Korrelationen zum GOS für die Kontusion im Hirnstamm, die Hirnstammschwellung und die Einengung der infratentoriellen Zisternen. Die supratentoriellen Befunde in CT und MRT korrelierten bis auf die Einengung der basalen Zisternen nicht mit dem GOS. Schädelbasis- und Mittelgesichtsfrakturen zeigten eine geringe Korrelation zur MRT-Klassifikation der Hirnstammläsionen. Infratentorielle Befunde, Schädelbasisfrakturen und Mittelgesichtsfrakturen im CT können Hinweise auf eine Hirnstammläsion sein. Schlussfolgerungen: Prognostische Vorhersagen bei Patienten mit einem SHT sind mit ausreichender Sicherheit nur mit der MRT-Klassifikation der Hirnstammläsionen möglich. Bei Patienten mit diskrepanter Klinik (anhaltende posttraumatische Bewusstlosigkeit) und ohne intrakranielle Verletzungszeichen im CT sollte ein MRT erfolgen.AbstractObjective: In this study the predictive value of neuroradiological investigations using computed tomography (CT) and magnetic resonance imaging (MRI) on patients suffering from head injuries is compared. Patients and Methods: 100 patients comatose for at least 24 hours after head injury were included. Outcome was classified according to the Glascow Outcome Scale (GOS). CT scans were performed on the day of the accident and MRI on average 5 days after trauma. Results: The highest correlation with the GOS (– 0,711, p = 0,01) was found for brain stem lesions. Less significant correlations with the GOS were shown for CT scan results corresponding to infratentorial injuries such as contusion within the brain stem, swelling of the brain stem or any compression of the infratentorial cisterns. The supratentorial injuries seen on CT or MRI did not correlate with the GOS except for any compressions of the basal cisterns. A loose relation was identified between skull base or mid-facial fractures and the MRI classification of brain stem lesions. Results of the CT-scans corresponding to infratentorial injuries, skull base or mid-facial fractures may suggest possible brain stem lesions. Conclusions: GOS of patients with head injuries can only be predicted using MRI exams. In patients showing unclear findings (e.g., continuous coma after trauma) without any intracranial lesions in the CT scans, MRI should be performed.