Gonca Erbas

Lowering the Dose in Head CT Using Adaptive Statistical Iterative Reconstruction

To avoid increased radiation exposure and subsequent long-term risk of cancer, iterative reconstruction is a means of lowering the dose on CT studies. Here, the authors compared head CT scans obtained via standard dose with low-dose (31% less) iterative reconstruction. Signal-to-noise and contrast-to-noise ratios as well as image noise, sharpness, artifacts, and diagnostic acceptability were assessed. Overall these parameters were judged to be better in the standard-dose CT, but those obtained with the lower dose and iterative reconstruction were judged acceptable. Thus, iterative reconstruction appears to be useful in adult head CT examinations. (Editors Note: This technique would be ideal in children where radiation dosage is of utmost concern. At my institution we use it for all head and neck studies, but not for temporal bone or paranasal sinus studies as we have found that bone detail may be less than optimal.) BACKGROUND AND PURPOSE: While CT has found wide use in medical practice, it is also a substantial source of radiation exposure and is associated with an increased lifetime risk of cancer. There is an urgent need for new approaches to reduce the radiation dose in CT. In this regard, ASIR is an alternative method to FBP. We assessed the effect of ASIR on dose reduction in adult head CT. MATERIALS AND METHODS: We retrospectively evaluated a sample of 149 adult head CT examinations that were divided into 2 groups, STD and LD. We lowered the tube current and used ASIR in the LD group. SNR and CNR were analyzed. Dose parameters were recorded while subjective image noise, sharpness, diagnostic acceptability, and artifacts were graded. The Student t test, the Mann-Whitney U test, and κ statistics were used for statistical analyses. RESULTS: We achieved a dose reduction of 31% in the LD group (STD, 2.3 ± 0.1 mSv; LD, 1.6 ± 0.1 mSv; P < .001). There was no significant difference in the noise measured in the air between the 2 comparison groups (P = .273). Noise in the CSF was higher in the STD group (P < .001), while the noise in the WM was higher in the LD group (P < .001). Differences in the CNR between groups were insignificant, but the STD group displayed better SNR values. There was no significant difference in the modal scores of diagnostic acceptability (P = .062) and the artifacts (P = .148) between the 2 groups. Better scores for subjective image noise (P < .001) and sharpness (P = .04) were observed in the STD group. CONCLUSIONS: ASIR appears to be useful in reducing the dose in adult head CT examinations. While the effect of ASIR on noise reduction observed in the present study of head CT is less than that reported previously in abdomen and chest CT, these findings encourage further prospective studies in larger patient samples.

Hematopoietic stem cell transplantation in patients with active fungal infection: not a contraindication for transplantation.

Increasing use of more aggressive treatment approaches in patients with hematologic malignancies leads to an increased frequency of invasive fungal infections, which is a major cause of transplant-related mortality in hematopoietic stem cell recipients. In this respect, the presence of an active fungal infection prior to transplantation may hinder subsequent hematopoietic stem cell transplantation (HSCT); which sometimes is the only curative treatment. We report here the results of 13 consecutive patients transplanted with active fungal infection. Thirteen patients (7 males and 6 females) with a median age of 34 years (range, 16-53 years) underwent 15 HSCT between September 2003 and April 2007. In this group of 15 patients, consisting of hematologic malignancies with high risk of relapse or severe aplastic anemia, 11 (73%) transplants performed in subjects with active invasive fungal infection (IFI) patients survived 30 days after transplantation. Three patients (1 patient with primary disease relapse, 1 patient with graft versus host disease [GVHD] complicated with fungal pneumonia, and 1 patient with severe sinusoidal obstruction syndrome and GVHD complicated with aspiration pneumonia) died on days +66, +74, and +62 posttransplantation, respectively, within the first 100 days of HSCT. After a median follow-up time of 306 days (range, 145-680 days), four of 13 (31%) patients with active IFI were alive and disease free. Among a population of HSCT recipients with a dismal prognosis without transplantation, performing the procedure despite active IFI saved a considerable proportion of the patients. The presence of active IFI did not seem to be an absolute contraindication for HSCT, particularly among high-risk patients in whom a treatment delay could be fatal.

Portomesenteric Venous Gas Imaging Findings With an Emphasis on Sonography

Objective. Portomesenteric venous gas is a rare condition with an unclear pathogenesis. Most studies in the medical literature mention computed tomography (CT) as the primary imaging tool for this entity. The objective of this study was to outline the advantages and disadvantages of sonography in the evaluation of patients with portomesenteric venous gas. Methods. We describe 7 patients (3 female and 4 male; age range, 47–83 years) with portomesenteric venous gas. Both CT and sonographic examinations were performed in each patient. Our patient population consisted of 2 patients with superior mesenteric artery occlusion, 3 with ischemia of the colon, small bowel, or both, 1 with gastric ulcer perforation, and 1 with ischemic bowel disease presumably secondary to complications of continuous ambulatory peritoneal dialysis. Results. Portal venous gas was observed in all 7 patients with sonography and in 6 patients with CT. Computed tomography was unable to show gas in the portal venous system in 1 patient. Sonography showed patchy hepatic gas accumulation (likely within small peripheral portal vein branches) with no correlative findings on CT. Computed tomography showed important associated findings, including pneumatosis intestinalis. Conclusions. In cases with portomesenteric gas, CT is the preferred modality for showing the underlying etiology. However, with its real‐time imaging capability, sonography may also be a very valuable imaging modality in the evaluation of this entity.

Value of fractional exhaled nitric oxide (FENO) for the diagnosis of pulmonary involvement due to inflammatory bowel disease

Background: Pulmonary involvement due to inflammatory bowel disease (IBD) is frequent when evaluating a patient with IBD and pulmonary involvement remains complicated. Most of the patients are asymptomatic and the methods used are mostly invasive or expensive procedures. The aim of this prospective study is to evaluate the value of the fractional exhaled nitric oxide (FENO) level for the diagnosis of pulmonary involvement due to IBD and to investigate any correlation between FENO level and disease activity. Methods: Thirty‐three nonsmoker patients with IBD (25 ulcerative colitis [UC] and 8 Crohns Disease [CD]) who were free of corticosteroid treatment and 25 healthy subjects as a control group were enrolled in this study. All patients with IBD were investigated for pulmonary involvement with medical history, physical examination, chest roentgenogram, oxygen saturation, blood eosinophil levels, pulmonary function tests (PFTs), high‐resolution computed tomography (HRCT), and FENO level. Results: Pulmonary involvement was established in 15 patients (45.5%) with IBD. The FENO level was higher in patients with pulmonary involvement than without pulmonary involvement and healthy controls independent from the pulmonary symptoms, eosinophil count, duration of disease, activity of disease, and surgery history (FENO: 32 ± 20; 24 ± 8; 14 ± 8 ppb, respectively) (P < 0.05). In addition, diffusion capacity (DLCO) was found to be significantly lower in patients with CD compared with UC (P < 0.05). Conclusions: This study showed that an increased FENO level may be used for identifying patients with IBD who need further pulmonary evaluation. Inflamm Bowel Dis 2009

Use of twinkling artifact in sonographic detection of intestinal pneumatosis

Intestinal pneumatosis is a relatively rare condition that has been associated with a wide variety of abnormalities. Traditionally, this entity has been diagnosed by radiographic films, contrast series, or more accurately by computed tomography. However, reports describing findings of intestinal pneumatosis on sonographic examination, which is an important initial diagnostic tool for abdominal diseases, are limited. We suggest that twinkling artifact may be of value in the sonographic diagnosis of this condition. We report two cases of intestinal pneumatosis that were diagnosed initially by sonography with the aid of twinkling artifact.

Doppler Sonographic Evaluation of Hemodynamic Changes in Colorectal Liver Metastases Relative to Liver Size

Objective. The mechanisms of hemodynamic alterations in colorectal liver metastases are not clearly understood yet. Considering that an increase in liver size in patients with metastases could also result in an alteration in total liver flow, we aimed to analyze hemodynamic changes relative to the liver volume and to search for the possibility of any intrinsic factors affecting blood flow in patients with metastases. Methods. Twenty‐eight patients with colorectal liver metastases and 20 control subjects with no liver disease were evaluated sonographically. All patients were examined prospectively by Doppler sonography and helical computed tomography. Hepatic hemodynamic parameters, including blood flow in the hepatic artery and portal vein, total blood flow to the liver, and Doppler perfusion index, were calculated, and values relative to liver volume were obtained. Hepatic perfusion changes in liver metastases were then compared with those in a control group. Results. The liver volume of the patients with liver metastases was greater than that of the control group (P = .003). Hepatic arterial blood flow rates were higher, whereas portal flow rates were lower, in patients with liver metastases compared with control subjects (P < .05). Total liver blood flow was not significantly different between the two groups. However, total blood flow relative to liver volume was significantly lower in the metastatic group (P < .001). Doppler perfusion index values in the patients with metastasis were significantly higher than in the control group (P = .000). Conclusions. Our findings may support the hypothesis that a humoral mediator‐induced portal venous flow reduction causes perfusion changes in liver metastases from colorectal disease. However, an additional intrinsic hepatic hemodynamic event should also be present. Doppler perfusion index measurements can provide additional information in the evaluation of patients with colorectal liver metastases.

Quantitative and qualitative comparison of standard-dose and low-dose pediatric head computed tomography: a retrospective study assessing the effect of adaptive statistical iterative reconstruction.

Objectives Our aim was to assess the effect of adaptive statistical iterative reconstruction (ASIR) on pediatric head computed tomography (CT) examinations. Methods We retrospectively reviewed 305 pediatric head CT examinations. The study population consisted of standard dose (STD, n = 152) examinations reconstructed with filtered back projection and low dose (LD, n = 153) examinations reconstructed with 30% (LD30) and 0% (LD0) ASIR. We compared groups by means of radiation dose, noise measures, and visual grading. Student t test, 1-way analysis of variance test, and Mann-Whitney U test were used for statistical analysis. Results The dose in the LD30 group was significantly lower (29%) than that in the STD group (P < 0.001). The noise in the white matter (P < 0.001), SNR (P < 0.001), and subjective image noise (P = 0.044) was significantly better in the STD group than those in the LD30 group. There was no significant difference between LD30 and STD groups in the sharpness (P = 0.141), diagnostic acceptability (P = 0.079), and artifacts (P = 0.750) and contrast-to-noise ratio (P = 0.718). Conclusions In conclusion, we found that a blend of 30% ASIR in a 16-slice multidetector CT produces diagnostically acceptable pediatric head CT examinations with a 29% less dose.

Endovascular treatment of obstructive iliac artery dissections

Purpose: To report our results from a study of the endovascular treatment of flow restricting chronic atherosclerotic or catheter‐induced segmental iliac artery dissections with bare stents. Material and Methods: Thirty symptomatic patients with 32 lesions, including chronic atherosclerotic (n = 21) and catheter‐induced (n = 11) segmental arterial dissections, were treated with primary stenting. The common iliac artery was involved in 19 lesions and the external iliac artery in the remaining 13. Two patients had two lesions in the same vessel. Technical success was defined as restoration of the smooth contoured luminal patency with no more than 20% residual stenosis in diameter in atherosclerotic dissections associated with plaque formation or total obliteration of the false lumen in catheter‐induced dissections. Complete relief of, or marked improvements in, presenting symptoms, or at least single category improvement, was assessed for clinical success. Results: Technical success rate was 100%. No procedure‐related complications such as distal emboli or early occlusions were observed. Complete symptom relief was achieved in all patients with catheter‐induced dissection and in all but three cases with chronic spontaneous atherosclerotic dissection. In two cases, occlusion of the stents occurred during the follow‐up period. Clinical and radiological mean follow‐up for 24 months (range 3–55) revealed patency of all other stented segments. Cumulative primary patency rate was 97% over 12 months and 90% over 24 months. Conclusion: Endovascular treatment of chronic atherosclerotic and catheter‐induced short obstructive iliac arterial dissections with bare stents is safe and effective. Patency of the diseased arterial segment with a smooth lumen can be sustained for an extensive period.

High ferritin levels are associated with hepatosplenic candidiasis in hematopoietic stem cell transplant candidates

OBJECTIVES Invasive fungal infections (IFI) are a significant cause of morbidity and mortality in hematopoietic stem cell transplant (HSCT) recipients. Hepatosplenic candidiasis (HSC) is defined as a distinct form of invasive candidiasis, with liver, spleen, and kidney involvement, in patients with hematological disorders. METHODS The charts of 255 patients (male/female 168/87; median age 35 (range 16-71) years) who were evaluated pre-HSCT at the Gazi University Hospital Stem Cell Transplantation Unit between 2003 and 2008, were retrospectively reviewed. RESULTS HSC, which was demonstrated in six (2.3%) patients, was found to be more common in allogeneic HSCT recipients than in autologous HSCT recipients and in patients who had received two or more previous chemotherapy courses than in patients who had received fewer than two (p>0.05). Patients with HSC tended to have a worse performance status than patients without HSC according to the World Health Organization (p=0.001) and Karnofsky scale (p=0.007). Pre-transplantation ferritin (p=0.008) and acute phase reactant levels, including erythrocyte sedimentation rate (p=0.025) and C-reactive protein (p=0.007), were significantly higher in patients with HSC than in patients without HSC. CONCLUSIONS This study shows the predictive role of pre-transplantation ferritin levels in selecting a subset of patients at increased risk for HSC. Pre-transplantation risk assessment and targeted strategies might lower the morbidity and mortality of IFI in HSCT recipients.

Corpus callosum hematoma secondary to isolated inferior sagittal sinus thrombosis

A 45-year-old female was admitted with headache and vomiting. Cranial computed tomography (CT) demonstrated a callosal hematoma. Magnetic resonance imaging (MRI) showed no venous flow and thrombus replacing the inferior sagittal sinus (ISS) lumen. Under appropriate medical treatment and close follow-up she recovered quickly and, after 2 years, was doing well with corpus callosum infarcts. Isolated inferior sagittal sinus thrombosis is an extremely rare condition with only one previously reported case in the literature. Although it is very rare, isolated inferior sagittal sinus thrombosis should be considered in the differential diagnosis of non-traumatic corpus callosum hematoma.