RESUMEN
Multidetector computed tomography (MDCT) has become the imaging method of choice in patients suspected of having pulmonary embolism (PE) but has the inherent limitation of radiation dose and the side effects of contrast agents. The purpose of the study was to assess the feasibility of a stepwise MRI protocol in the clinical setting of acute PE. The stepwise approach should make it possible to diagnose acute PE in critically ill patients using fast MR sequences and included the option to add comprehensive sequences when patients were stable. Forty-five patients with acute PE (26 men, 19 women; 41 ± 16 years) were included in this prospective study. The diagnosis was initially confirmed by MDCT as gold standard. MRI at 1.5 T was subsequently performed without any delay in medical treatment. The MRI protocol proceeded stepwise from robust to detailed imaging techniques (i.e., from TrueFISP and single shot HASTE sequence to MR perfusion and 3D-MR angiography) if the patient was able to tolerate additional imaging time. Diagnostic accuracy was evaluated on the central (lobar) and peripheral (segmental) levels. The complete MR protocol was applied in 40 of the 45 patients (88 %). In the remaining five patients with severe dyspnea the diagnosis of acute PE was established by using fast TrueFISP sequences that were insensitive to respiratory movement. All five patients suffered from a major central PE. Highest sensitivity was achieved by MR perfusion (lobar, 98 %; segmental, 95 %). Real-time TrueFISP and MR angiography showed the highest specificity (lobar, 90-100 %; segmental, 95-97 %). The combination of all MR sequences matched closely the results of MDCT (lobar: sensitivity 98 %, specificity 100 %; segmental: sensitivity 95 %, specificity 97 %). MRI using a stepwise protocol is a promising approach for diagnosing acute PE. The protocol can be tailored for dyspneic patients with central PE using real-time MRI sequences. The diagnostic accuracy for peripheral PE can be improved by using combined MR techniques, achieving comparable results to MDCT.
Asunto(s)
Imagen por Resonancia Magnética/métodos , Embolia Pulmonar/diagnóstico , Enfermedad Aguda , Adulto , Estudios de Factibilidad , Femenino , Humanos , Angiografía por Resonancia Magnética , Masculino , Tomografía Computarizada por Rayos XRESUMEN
PURPOSE: To assess coronary artery image quality and patient radiation exposure in patients who underwent clinically indicated 256-slice CTA. METHODS: Consecutive patients (n=193) underwent 256-slice CTA, using (1) retrospective gating without radiation dose modulation, (2) retrospective gating with radiation dose modulation and (3) prospective gating. Image quality was determined by consensus of two experienced observers using a 5-grade scale. The effective dose was calculated. RESULTS: In all patients, CTA was performed without adverse events. Retrospective CTA was assessed in 39 patients with and 39 without dose modulation, while 115 patients underwent prospective CTA. Heart rate was related to image quality with all protocols (r=0.46, p<0.001). Up to a heart rate of 75 bpm no significant difference in overall image quality was observed for all three protocols, while no significant differences could be observed between retrospective CTA with and without dose modulation for any segments or heart rates. Prospective and retrospective CTA with dose modulation showed radiation savings of â¼75 % and â¼30 %, respectively compared to retrospective CTA without dose modulation (p<0.001). CONCLUSIONS: In patients with heart rates up to 75 bpm prospective CTA should be the first choice acquisition protocol. For heart rates >75 bpm, retrospective CTA with dose modulation should be considered.
Asunto(s)
Angiografía Coronaria , Enfermedad de la Arteria Coronaria/diagnóstico por imagen , Tomografía Computarizada Multidetector/métodos , Dosis de Radiación , Femenino , Frecuencia Cardíaca , Humanos , Masculino , Persona de Mediana EdadRESUMEN
Trigeminal neuralgia (TN) is a pain state characterized by intermittent unilateral pain attacks in one or several facial areas innervated by the trigeminal nerve. The somatosensory cortex is heavily involved in the perception of sensory features of pain, but it is also the primary target for thalamic input of nonpainful somatosensory information. Thus, pain and somatosensory processing are accomplished in overlapping cortical structures raising the question whether pain states are associated with alteration of somatosensory function itself. To test this hypothesis, we used functional magnetic resonance imaging to assess activation of primary (SI) and secondary (SII) somatosensory cortices upon nonpainful tactile stimulation of lips and fingers in 18 patients with TN and 10 patients with TN relieved from pain after successful neurosurgical intervention in comparison with 13 healthy subjects. We found that SI and SII activations in patients did neither depend on the affected side of TN nor differ between operated and nonoperated patients. However, SI and SII activations, but not thalamic activations, were significantly reduced in patients as compared to controls. These differences were most prominent for finger stimulation, an area not associated with TN. For lip stimulation SI and SII activations were reduced in patients with TN on the contra- but not on the ipsilateral side to the stimulus. These findings suggest a general reduction of SI and SII processing in patients with TN, indicating a long-term modulation of somatosensory function and pointing to an attempt of cortical adaptation to potentially painful stimuli.
Asunto(s)
Mapeo Encefálico , Corteza Somatosensorial/fisiopatología , Tacto/fisiología , Neuralgia del Trigémino/patología , Adulto , Anciano , Analgésicos no Narcóticos/farmacología , Analgésicos no Narcóticos/uso terapéutico , Carbamazepina/farmacología , Carbamazepina/uso terapéutico , Femenino , Dedos/inervación , Humanos , Procesamiento de Imagen Asistido por Computador/métodos , Labio/inervación , Imagen por Resonancia Magnética/métodos , Masculino , Persona de Mediana Edad , Vías Nerviosas/fisiopatología , Oxígeno/sangre , Dimensión del Dolor , Corteza Somatosensorial/irrigación sanguínea , Corteza Somatosensorial/efectos de los fármacos , Adulto JovenRESUMEN
We report a rare case of two communicating pseudoaneurysms of the common hepatic artery 1 month postoperatively following pylorus-preserving pancreaticoduodenectomy due an abscess formation. We describe the superselective transcatheteral embolization technique with deployment of interlocking detachable coils and Histoacryl-Lipiodol in this case and discuss the recent literature. Despite the technical success by achieving hemodynamic stability with initial preservation of liver function, the patient died 23 days postembolization due to multiorgan failure.