Standardization of MIP Technique in Three-dimensional CT Portography: Usefulness in Evaluation of Portosystemic Collaterals in Cirrhotic Patients

PURPOSE: To assess the usefulness of three-dimensional CT portography using a standardized maximum intensity projection (MIP) technique for the evaluation of portosystemic collaterals in cirrhotic patients. MATERIALS AND METHODS: In 25 cirrhotic patients with portosystemic collaterals, three-phase CT using a multidetector-row helical CT scanner was performed to evaluate liver disease. Late arterial-phase images were transferred to an Advantage Windows 3.1 workstation (Gener Electric). Axial images were reconstructed by means of three-dimensional CT portography, using both a standardized and a non-standardized MIP technique, and the respective reconstruction times were determined. Three-dimensional CT portography with the standardized technique involved eight planes, namely the spleno-portal confluence axis (coronal, lordotic coronal, lordotic coronal RAO 30 degree, and lordotic coronal LAO 30 degree), the left renal vein axis (lordotic coronal), and axial MIP images (lower esophagus level, gastric fundus level and splenic hilum). The eight MIP images obtained in each case were interpreted by two radiologists, who reached a consensus in their evaluation. The portosystemic collaterals evaluated were as follows: left gastric vein dilatation; esophageal, paraesophageal, gastric, and splenic varix; paraumbilical vein dilatation; gastro-renal, spleno-renal, and gastrospleno-renal shunt; mesenteric, retroperitoneal, and omental collaterals. RESULTS: The average reconstruction time using the non-standardized MIP technique was 11 minutes 23 seconds, and with the standardized technique, the time was 6 minutes 5 seconds. Three-dimensional CT portography with the standardized technique demonstrated left gastric vein dilatation (n=25), esophageal varix (n=18), paraesophageal varix (n=13), gastric varix (n=4), splenic varix (n=4), paraumbilical vein dilatation (n=4), gastro-renal shunt (n=3), spleno-renal shunt (n=3), and gastro-spleno-renal shunt (n=1). Using three-dimensional CT portography and the non-standardized MIP technique, the portosystemic collaterals demonstrated were similar to those demonstrated using the standardized technique. Additionally, howerer, the former revealed features not revealed by the latter, namely splenic varix (n=1), mesenteric collaterals (n=4), retroperitoneal collaterals (n=3), and omental collaterals (n=2). CONCLUSION: In patients with liver desease, three-dimensional CT portography using a standardized of MIP technique helps evaluate portosystemic collaterals, reduces interobserver bias, and saves reconstruction time.

Three-Dimensional CT Laryngography: Clinical Application

PURPOSE: To evaluate the clinical usefulness of 3D volume-rendering (VR) CT laryngography during quiet breathing, Valsalva, and modified Valsalva maneuvers, in those with laryngeal and pyriform sinus lesions. MATERIALS AND METHODS: Twenty-seven patients with various laryngeal and hypopharyngeal lesions were examined by means of four-channel multidetector-row helical CT (LightSpeed QX/i; GE Medical Systems, Milwaukee, Wis., U.S.A.) during quiet breathing, Valsalva, and modified Valsalva maneuvers. The protocol included 1.25-mm slice thickness, 3.75-mm rotation, 1.25 mm interval, and a pitch ratio of 3:1. Using an Advantage Windows 3.1 workstation (GE Medical Systems), 3D VR was generated in regions of interest, including all structures with a CT attenuation of between -1022 and -125 HU. Visual assessment of the findings of 3D CT laryngography, including the images obtained during the three different breathing maneuvers, were analyzed by three radiologists, who reached a consensus. These results were then compared with the findings of axial CT. The lesions discovered, in descending order of frequency, included laryngeal cancer (n=12), pyriform sinus cancer with an intact apex (n=6), pyriform sinus cancer with apex involvement (n=6), laryngeal papilloma (n=2), and hypopharyngeal obstruction with (n=1) and without (n=2) associated vocal cord palsy. In each case, the findings were confirmed by surgical biopsy, direct laryngoscopy, or CT. RESULTS: 3D CT laryngography using the VR technique can supplement the information provided by axial images, and in the assessment of subglottic invasion and pyriform sinus apical invasion, its findings are consistent. In many of our cases, its use during quiet breathing was able to determine whether or not glottic cancer involved subglottic invasion. In laryngeal cancer cases, furthormore, modified Valasalva can be used to clarify the condition of the pyriform sinus apex. Dynamic-phase 3D CT laryngography can be used to elucidate the condition of a patient with vocal cord palsy. CONCLUSION: 3D CT laryngography is a new method for the visual diagnosis of vocal cord and laryngeal cancer. When employed after dynamic diagnosis, it is useful for the evaluation of subglottic extension, pyriform sinus apical invasion and vocal cord palsy, important indicators in the staging of cancer.

Contralateral Hyperperfusion on Single Photon Emission ComputedTomograhy (SPECT) in the Patient with Todd's Paralysis

It has been known that the usual findings of SPECT in patients with Todd's paralysis is the hypoperfusion of the corresponding hemisphere. We experienced a patient who developed transient hemiparesis after a seizure attack with hyperperfusion rather than hypoperfusion over the corresponding hemisphere on brain SPECT. A 36-year-old female presented with left hemiparesis after a secondarily generalized tonic seizure. No additional seizure-like attack was noted during admission. EEG showed intermittent focal slow waves over the right frontotemporal area on admission and returned to a normal pattern 72 hours after admission. Tc-99m ECD SPECT showed hyperperfusion on the right frontoparietal area in spite of the normalization of EEG. The degree of hyperperfusion was diminished as time passed for at least 72 hours. We report a patient who had Todd's paralysis associated with contralateral frontoparietal hyperperfusion. Todd's paralysis may be explained as the result of focal discharges that lead to local vasomotor changes.

The Safety and Feasibility of Transradial Primary Coronary Intervention in Acute Myocardial Infarction

BACKGROUND AND OBJECTIVES: Aggressive antithrombotic therapy and transfemoral primary intervention during acute myocardial infarction (AMI) restricts the patient's movement and may increase the risk of access site bleeding complications, and lengthen the duration of movement restriction and hospital stay. Transradial approach provides less bleeding complications and early ambulation. The purpose of this study is to know whether transradial primary intervention is safe and feasible in the patients with AMI. MATERIALS AND METHOD: From April 1998 to December 1998, transradial primary interventions were performed in the consecutive 28 patients (24 male, 57+/-7 years) by two experienced operators. The results were compared to the results of 44 (15 patients during same period, 29 during previous year) transfemoral primary interventions. RESULTS: 1)The success rates of transradial primary interventions was 93% (26/28) and comparable to 95% (42/44) of transfemoral primary interventions. 2)In transradial group, the time from the arrival of catheterization laboratory to arterial access and to reperfusion, the time from the arrival of emergency room to reperfusion were 8.1+/-3.4 minutes, 22.0+/-5.3 minutes, and 71.7+/-9.2 minutes, respectively and comparable to 9.0+/-3.1 minutes, 21.7+/-5.3 minutes, and 68.9+/-8.1 minutes of transfemoral group, respectively. 3)The complications of the procedure were treated successfully during transradial interventions. 4)In transradial group, puncture site bleeding complications were absent though heparin was continued and mild ambulation was possible early after the procedure. The hospital stay of transradial group was 5.3+/-1.3 days and shorter than 7.7+/-4.2 days of transfemoral group. CONCLUSION: In the low risk patients with AMI, transradial primary intervention might be safe and feasible with acceptable time delay by the experienced operators. It might be effective to reduce access site bleeding complications and to initiate early ambulation, resulting in the shortened hospital stay.