Automated volumetry at CT colonography: a phantom study

RATIONALE AND OBJECTIVES: To assess the performance of a computer-aided detection (CAD) algorithm for measuring polyp-like structures on CT colonography (CTC) images of a phantom. MATERIALS AND METHODS: We constructed a Plexiglas phantom to which we affixed a series of idealized Plexiglas polyp-like objects, including spheres and hemispheres. We imaged the phantom in a four-channel detector CT scanner at a 1.3 mm slice thickness with a reconstruction interval of 0.6 mm, using combinations of 100 mAs, 30 mAs, horizontal and vertical orientation. For each set of CT images, the interior surface of the phantom was segmented. The CAD algorithm was applied to the resulting surface to identify the polypoid regions of interest and to calculate their volume and maximum linear dimension. Calculated values were then compared with actual values to yield percent error in each measurement. RESULTS: The mean error in volume for the subgroups of spheres and hemispheres was 3% and 5% respectively. Mean error in linear dimension was approximately 2% for both shape subgroups. All CAD-calculated values were closely correlated with their respective actual values. Parameter selection did not significantly affect the accuracy of the calculated measurements. CONCLUSIONS: Our CAD software accurately measured the greatest linear dimension and the volume of each of the polyp-like structures in our phantom. Results were largely independent of phantom orientation and the CT exposure factors.     

Use of 3D imaging in CT of the acute trauma patient: impact of a PACS-based software package

To evaluate the impact of a picture archiving and communication systems (PACS)–based software package on the requests for 3D reconstructions of multidetector CT (MDCT) data sets in the emergency radiology of a level 1 trauma center, we reviewed the number and type of physician requests for 3D reconstructions of MDCT data sets for patients admitted after sustaining multiple trauma, during a 12-month period (January 2003–December 2003). During the first 5 months of the study, 3D reconstructions were performed in dedicated workstations located separately from the emergency radiology CT interpretation area. During the last 7 months of the study, reconstructions were performed online by the attending radiologist or resident on duty, using a software package directly incorporated into the PACS workstations. The mean monthly number of 3D reconstructions requested during the two time periods was compared using Students t test. The monthly mean ± SD of 3D reconstructions performed before and after 3D software incorporation into the PACS was 34±7 (95% CI, 10–58) and 132±31 (95% CI, 111–153), respectively. This difference was statistically significant (p<0.0001). In the multiple trauma patient, implementation of PACS-integrated software increases utilization of 3D reconstructions of MDCT data sets.This paper has been accepted for presentation at the 15th Annual Scientific Meeting of the ASER in Montreal, Canada, September 8–11, 2004     

Hand involvement in paraneoplastic syndrome: a case report

Cutaneous paraneoplastic syndromes are skin and mucous membrane changes that are associated with cancer. We report a previously healthy 76-year-old man who developed marked finger and thumb contracture, pain, and hypersensitivity of both hands who was diagnosed subsequently as having gastric carcinoma with colonic metastasis. After the gastrointestinal tumors were resected the finger and thumb contracture lessened and the pain eased. Both the temporal relationship between the changes in the hand and the neoplasm and the improvement after resection suggest a paraneoplastic syndrome.     

Large pseudoaneurysm of left ventricle following cardiac surgery

A 75-year old female patient, with previous inferior acute myocardial infarction (AMI) in December 2000, was admitted in April 2001 with angina and heart failure. Transthoracic echocardiography (TTE) was suggestive of a postero-inferior pseudoaneurysm (PA) of the left ventricle (LV), with 61x49 mm. of size and mitral regurgitation. Cardiac catheterization was suspected of a PA of the LV and revealed a three vessels coronary artery disease. On 20th April she was submitted to cardiac surgery with resection of a large LV aneurysm (AN) and triple coronary artery bypass surgery. Afterwards, she was on NYHA class III and subsequent TTE and transesophagic echocardiography (TEE) were suggestive of a 90x60 mm LV posterior PA (confirmed by nuclear magnetic resonance) and severe mitral regurgitation, with good LV systolic function. She underwent a new cardiac surgery on 31st May 2002, with resuturing of the LV postero-inferior wall patch and removal of the PA. The patient is in good condition and on NYHA functional class I-II.     

American Society of Diagnostic and Interventional Nephrology Section Editor: Stephen Ash: Does Catheter Insertion by Nephrologists Improve Peritoneal Dialysis Utilization? A Multicenter Analysis

In contrast to hemodialysis (HD), peritoneal dialysis (PD) remains an underutilized form of renal replacement therapy in the United States. Although a variety of factors have been deemed responsible, timely insertion of a PD catheter may also be a contributory factor. We conducted a multicenter analysis to examine whether the establishment of a program for PD catheter insertion by nephrologists has a positive impact on the growth in the number of patients using PD. Data for catheter insertion performed by nephrologists were collected from three centers. Any change in the prevalent PD population at each respective center was compared to the number of PD patients during the period having the traditional surgical approach. Nephrologists at the three centers used the peritoneoscopic technique and performed catheter insertion under local anesthesia. In center 1, the PD population remained stable at between 38 and 45 patients (approximately 16% of the total end-stage renal disease [ESRD] population) from 1993 to 2001. Nephrologists initiated a program for PD catheter insertion in 2001. The number of PD patients has increased to 101 (32% of the ESRD population). In center 2, the PD population remained stable at between 70 and 78 patients (approximately 17%) between 1988 and 1990. Catheter insertion by interventional nephrologists began in 1991. The number of PD patients has increased to 125 (22%). In center 3, the PD population remained at 20-30 patients (approximately 18%) between 1988 and 1991. Catheter placement by nephrologists was initiated in 1991. The number of PD patients increased to 97 (27%). Catheter insertion by interventional nephrologists was suspended in 2001. The number of PD patients has gradually declined to 25 (6%). This study suggests that catheter insertion by the nephrologist can have a positive impact on the utilization of PD.     

Evaluation and management of renal tumors in the Birt-Hogg-Dubé syndrome

PURPOSE: Herein we describe the evaluation and management of renal tumors in Birt-Hogg-Dubé (BHD), an autosomal dominant disorder predisposing to cutaneous fibrofolliculomas, pulmonary cysts, spontaneous pneumothorax and renal tumors. MATERIALS AND METHODS: A total of 124 affected individuals underwent comprehensive clinical evaluation, including body computerized tomography, to determine cutaneous, pulmonary and renal manifestations of BHD. Of these individuals 14 had their renal tumors managed at our institution. RESULTS: Of the 124 BHD affected individuals 34 (27%) had renal tumors of various histologies, most commonly hybrid oncocytic tumor and chromophobe renal carcinoma. Average age at renal tumor detection was 50.4 years and multiple tumors were found in a majority of patients. Some patients with renal tumors were identified that did not have the characteristic cutaneous hallmarks of BHD. In 4 of the 14 patients treated at our institution small (less than 3 cm) renal tumors were observed, while 10 others underwent a total of 12 renal procedures, including 4 radical and 8 partial nephrectomies. At a median of 38 months of followup 5 of these 10 patients remained free of disease, 3 had small renal tumors and 2 died of metastatic renal cancer. CONCLUSIONS: Patients with BHD are at risk for multiple renal tumors that are often malignant and can metastasize. Individuals at risk or affected by BHD should be radiographically screened for renal tumors at periodic intervals and they are best treated with nephron sparing surgical approaches. Genetic testing for this syndrome is now available.     

N1/P2 component of auditory evoked potential reflect changes of the brain serotonin biosynthesis in rats

It is known that L-tryptophan stimulates serotonin synthesis in the brain and serotonergic neuronal activity. Also, the N1/P2 component of auditory evoked potential (AEP) is a good indicator of this activity in the auditory cortex. In the present work, we examined the effect of the L-tryptophan administration on electric activity of the auditory cortex recorded as the N1/P2 component of the AEP in adult male rats. The effect of serotonergic agonists or antagonists was also tested. The results showed that indeed L-tryptophan was able to induce a drastic change in auditory cortex electric activity, reducing very significantly the amplitude of the N1/P2 component of the AEP. Quipazine maleate had a similar effect as L-tryptophan and the serotonergic antagonist spiperone induced an increase in the N1/P2 amplitude. These results show how an isolated nutrient is able to induce significant changes in brain auditory cortical function, through stimulation of serotonin synthesis. Besides, they add evidence about the important role of serotonergic neurotransmission modulating sensory cortical activity and that the N1/P2 component of AEPs represent a useful noninvasive indicator of brain serotonin tone.