N. Gourtsoyiannis

Determination of normal splenic volume on computed tomography in relation to age, gender and body habitus

Abstract The purpose of our study was to examine variations in normal splenic size in relation to age, gender and body habitus in vivo, and to determine normative data for splenic volume on CT. The width (W), length (L), thickness (Th), cross-sectional areas and volume (Vol) of the spleen were obtained from abdominal CT examinations of 140 patients who underwent CT for indications unrelated to splenic disease. Splenic volume did not vary significantly (–0.04 < r < 0.05, p > 0.10) with the patients age, gender, height, weight, body mass index or the diameter of the first lumbar vertebra, the latter considered as representative of body habitus on CT. The mean value of the measured splenic volume (S Vol) was 214.6 cm3 with a range from 107.2 to 314.5 cm3. S Vol correlated well with all the linear and the maximal cross-sectional area measurements and could be calculated using the formula: S Vol = 30 + 0.58 (W × L × Th.). Employing the same formula splenic volume was reliably assessed in 47 patients with clinically evident splenomegaly. Quantitative assessment of splenic volume might be of value in assessing mild variations in splenic size, because splenomegaly is the most common manifestation of splenic involvement in many disorders.

The effect of z overscanning on patient effective dose from multidetector helical computed tomography examinations

z overscanning in multidetector (MD) helical CT scanning is prerequisite for the interpolation of acquired data required during image reconstruction and refers to the exposure of tissues beyond the boundaries of the volume to be imaged. The aim of the present study was to evaluate the effect of z overscanning on the patient effective dose from helical MD CT examinations. The Monte Carlo N-particle radiation transport code was employed in the current study to simulate CT exposure. The validity of the Monte Carlo simulation was verified by (a) a comparison of calculated and measured standard computed tomography dose index (CTDI) dosimetric data, and (b) a comparison of calculated and measured dose profiles along the z axis. CTDI was measured using a pencil ionization chamber and head and body CT phantoms. Dose profiles along the z axis were obtained using thermoluminescence dosimeters. A commercially available mathematical anthropomorphic phantom was used for the estimation of effective doses from four standard CT examinations, i.e., head and neck, chest, abdomen and pelvis, and trunk studies. Data for both axial and helical modes of operation were obtained. In the helical mode, z overscanning was taken into account. The calculated effective dose from a CT exposure was normalized to CTDIfreeinair. The percentage differences in the normalized effective dose between contiguous axial and helical scans with pitch=1, may reach 13.1%, 35.8%, 29.0%, and 21.5%, for head and neck, chest, abdomen and pelvis, and trunk studies, respectively. Given that the same kilovoltage and tube load per rotation were used in both axial and helical scans, the above differences may be attributed to z overscanning. For helical scans with pitch=1, broader beam collimation is associated with increased z overscanning and consequently higher normalized effective dose value, when other scanning parameters are held constant. For a given beam collimation, the selection of a higher value of reconstructed image slice width increases the normalized effective dose. In conclusion, z overscanning may significantly affect the patient effective dose from CT examinations performed on MD CT scanners. Therefore, an estimation of the patient effective dose from MD helical CT examinations should always take into consideration the effect of z overscanning.

Radiation dose to conceptus resulting from tangential breast irradiation

PURPOSE To estimate the radiation dose to the conceptus resulting from tangential breast irradiation. METHODS AND MATERIALS Conceptus radiation doses were measured in anthropomorphic phantoms simulating the geometry of a pregnant woman at the first, second, and third trimesters of gestation. Medial and lateral field irradiations were generated using a 6-MV X-ray beam. Dose measurements were performed with thermoluminescent dosimeters. RESULTS For a treatment course delivering 50 Gy to the tumor, conceptus dose at the first trimester of gestation was found to be 2.1-7.6 cGy, depending on the field size used and the distance between conceptus and primary irradiation field. The corresponding dose ranges to the conceptus during the second and third trimesters of gestation were 2.2-24.6 cGy and 2.2-58.6 cGy, respectively. Dose data and formulas are presented to estimate conceptus dose for individual patients undergoing breast radiotherapy during the entire pregnancy. CONCLUSIONS This study may be of value in the management of pregnant women needing tangential breast irradiation, because it provides the required information to estimate conceptus dose.

Uncommon locations of hydatid disease: CT appearances

Abstract Hydatid disease (HD), already known by Hippocrates, is prevalent and widespread in most sheep-raising countries in Asia, Australia, South America, Near East, and southern Europe. The disease is most commonly due to Echinococcus granulosus and may occur in any organ or tissue. The location is mostly hepatic (75 %) and pulmonary (15 %), and only 10 % occur in the rest of the body [1]. Imaging modalities such as US, CT, and MR imaging are helpful in diagnosing the disease. The reliability of each method depends on the cysts location in the body [2–5]. The purpose of this essay is to illustrate the use of CT in depicting some unusual locations of HD besides the liver and lung.

Acute abdomen due to torsion of wandering spleen: CT diagnosis

Abstract. Two adults and a child with acute abdomen and surgically confirmed torsion of wandering spleen are presented. Computed tomography provided a spectrum of findings including an ovoid or comma-shaped abdominal mass, hypertrophy of the livers left lobe, a whirled appearance of hyperdense, nonenhancing splenic vessels, and an enlarged spleen, exhibiting minimal or no enhancement. Computed tomography also indicated the point of torsion and the viability of splenic parenchyma.

Blueberry juice used per os in upper abdominal MR imaging: composition and initial clinical data.

The aim of this study was to evaluate the use of a commercially available blueberry juice (BJ) both as a positive and negative oral contrast agent and to present the exact contents of paramagnetic ions. The concentration of Mn and Fe were determined in tinned myrtilles in syrup (atomic absorption). Nine healthy volunteers and 12 patients (age range 20–65 years) were examined using a 1-T MR scanner before and after per os administration of 430 ml of BJ. A qualitative analysis of signal alterations in the stomach, duodenum, and proximal small intestine was performed. In addition, a quantitative analysis was assessed in terms of signal-to-noise ratio calculation. The mean concentration (× ± SD) of the ions found in the content of the three cans were 3.3±0.4 µg/g for iron and 20.6±2.6 µg/g for manganese. Based on the qualitative evaluation, signal alteration on T1-weighted images after administration of BJ was statistically significant in the stomach and duodenum, but not in the proximal small bowel. Signal alteration on T2-weighted images was not statistically significant in any part of the gastrointestinal tract. The quantitative analysis of the T1- and T2 shortening showed that BJ is efficient with only T1-weighted sequences, and this applied to the stomach, duodenum, and proximal small bowel. Blueberry juice can be used as an oral contrast agent in upper abdominal MR for T1-weighted imaging.

Benign tumors of the small intestine: preoperative evaluation with a barium infusion technique.

During a seven year period 18 benign small intestinal tumors were histologically documented in patients referred to us for a small bowel study, using a barium infusion technique. These included seven leiomyomas, five adenomatous polyps, two Peutz-Jeghers hamartomas, one myoepithelial hamartoma, one lipoma, one Brunners gland adenoma and one neurilemmoma. Ten of the patients were women and eight were men, with their ages ranging from 20 to 75 years (mean age 45 years). Presenting symptoms were gastrointestinal bleeding in 12, anemia in 9, abdominal pain in 4, partial intestinal obstruction in 3 and bloody diarrhea in one. The time elapsed from onset of symptoms to radiological diagnosis ranged between one month and seven years (mean time 16 months). Multiple lesions were encountered in four cases and solitary in fourteen. The site of involvement was the duodenum in 3 patients, the jejunum in 8 and the ileum in 7 of them. Main radiological appearances included solitary or multiple intraluminal filling defects, mass effect on neighbouring loops and dilation of intestinal loops proximally to the lesion. The primary tumor, in the form of a mass or other abnormality of the small intestine was identified in all study cases. Correlation with surgical or endoscopic findings showed that radiology depicted all single lesions, whereas multiple lesions were underestimated in one case. The individual morphological changes shown on examination of the resected specimens resembled the appearances on the barium study in all cases. However, enteroclysis missed four out of seven ulcers and a stalk in one of the five pedunculated lesions. A specific tumor-type diagnosis was reached preoperatively in eleven patients, it was suggestive in five and mistaken in two of them. Our experience indicates that enteroclysis is an effective means in evaluating patients with suspected benign small bowel tumors, preoperatively.

Imaging Ultrasonometry of the Calcaneus: Optimum T-Score Thresholds for the Identification of Osteoporotic Subjects

The purpose of the present study was to (1) examine the age dependence of T-score results for calcaneal imaging ultrasonometry and dual X-ray absorptiometry of the axial skeleton and (2) determine the optimum T-score thresholds appropriate for broadband ultrasound attenuation (BUA) and speed of sound (SOS) measurements. A total of 453 healthy women aged 20-9 years were included in the study. All study participants underwent bone mineral density (BMD) measurements of the lumbar spine, femoral neck, total hip and calcaneal measurements of the BUA and SOS. An imaging ultrasound device (UBIS, DMS, France) was used for the ultrasound measurements. T-scores were calculated using a subgroup of 71 healthy women aged 20-35 years to estimate the mean value of young normals and SD for BUA, SOS, and BMD. The age-related decline in both BUA and SOS T-scores was slower than that in the equivalent figures obtained by BMD measurements. The optimum T-score thresholds estimated by receiver operating characteristic (ROC) analysis were 1.3 for BUA and 1.5 for SOS. Using the optimum threshold, the sensitivity and specificity for BUA was 68% and 83%, respectively. Corresponding values for SOS were 63% and 79%. Utilizing calculated optimum T score thresholds for BUA and SOS, the agreement among BUA, SOS, and BMD at the femoral neck was improved compared with that found using the T-score of < or = -2.5 criterion. In conclusion, the definition of osteoporosis by a T-score of , or = -2.5 was not applicable to imaging ultrasonometry of the calcaneus. Optimum T-score thresholds were determined for both BUA and SOS suitable to Ubis QUS device.

Preoperative imaging staging of rectal cancer

Carcinomas of the rectum are associated with a significant local and distant recurrence rate. Not all patients are appropriate candidates for preoperative radiation therapy. Preoperative identification of those most likely to benefit from neoadjuvant therapy is important. There is no general consensus on the role of endorectal ultrasonography, computed tomography (CT), and magnetic resonance imaging (MRI) in staging patients with rectal cancer. Although the tumor stage is an important prognostic factor, preoperative assessment is associated with prediction of the circumferential resection margin. Newer developments such as coils, sequences and gradients in MRI, evolution of multidetector CT and new contrast media, allow for an algorithm selection aiming at the best diagnostic options for patients. The present review will discuss the current role of the various imaging modalities in staging carcinomas of the rectum.

High-resolution and color doppler ultrasonography of cervical lymphadenopathy in children

PURPOSE To assess the frequency of high-resolution and color Doppler sonographic findings in the most common diseases of childhood manifested with cervical lymphadenopathy at initial presentation. MATERIAL AND METHODS High-resolution and color Doppler US were performed in 103 and 43 children respectively, with cervical lymphadenopathy at initial presentation. Sonomorphology and intranodal vascularity were assessed. Final diagnoses, based on biopsy or clinical and sonographic follow-up, included: Reactive hyperplasia (n=34), infectious mononucleosis (n=20), lymphoma (n=11), bacterial (n=28), tuberculous (n=5) and cat-scratch disease (CSD, n=5) lymphadenites. RESULTS Round shape (L/S<2) was common both in lymphoma (78%), infectious mononucleosis (85%) and bacterial lymphadenitis (73%) while 91% of reactive nodes had L/S>2. Wide hilum conforming to nodal shape characterized reactive hyperplasia (94%) and infectious mononucleosis whereas absent or narrow hilum was frequent in lymphoma (100%) and bacterial lymphadenitis (60%). Central irregular hyperechogenic areas, blurred margins and central necrosis were most frequent in bacterial, tuberculous and CSD lymphadenites. On color Doppler US, hyperplastic nodes more frequently exhibited a solitary hilar vessel (48%), whereas infectious mononucleosis nodes had a central radial pattern (75%). Bacterial lymphadenitis presented with a variety of vascular patterns. CONCLUSION Although individual sonographic signs are not specific, the categorization and combination of findings might be highly suggestive of diagnosis of the underlying disease presenting with cervical lymphadenopathy.