Formation of calcium alginate gel capsules: Influence of sodium alginate and CaCl2 concentration on gelation kinetics

The formation kinetics of calcium alginate gel capsules is studied. An increase in the concentration of alginate gives rise to a reduction in membrane thickness, while an increase in the concentration of calcium chloride leads to the formation of a thicker film. Experimental data are adjusted to the binomial diffusion equation.

[Magnetic resonance pyelography: clinical use of ultrafast breath-hold sequences in obstructive uropathy. Personal experience]

INTRODUCTION

We investigated the diagnostic yield of MR pyelography (MRP) performed with two ultrafast breath-hold sequences in obstructive uropathy patients.

MATERIAL AND METHODS

Thirty-four patients with US demonstration of urinary tract dilation were examined with MRP at 1.5 T and with a standard body coil. HASTE sequences (TE 66, ETL 128, FA 180 degrees, 1 NEX, MA 240 x 256, slice thickness 4 mm, TA 13 s) were always performed and 26/34 patients were also examined with single-shot TSE sequences (TE 1100, ETL 240, FA 150 degrees, 1 NEX, slice thickness 7 cm, MA 240 x 256, FS, TA 7 s); 20/34 patients were given 500 mL superparamagnetic contrast agent (Lumirem). MRP findings were interpreted independently by two radiologists and analyzed for image quality, the presence/absence of dilation, the obstruction grade (mild, moderate, severe), site (intrarenal; ureteropelvic junction; proximal, mid-, distal ureter; indeterminate) and cause (intrinsic obstruction from a stone or other conditions; stenosis; indeterminate cause). The sensitivity, specificity, positive and negative predictive values for the detection of urinary tract dilation were calculated for each reviewer and interobserver agreement was calculated with the k analysis relative to the presence, grade, site and cause of urinary tract dilation.

RESULTS

MRP examinations were considered technically adequate in all cases by both observers. As for the presence of urinary tract dilation, the values were 100% for the first observer and 97%, 100%, 100%, and 95%, respectively, for the second observer. Interobserver agreement was .98 for dilation presence (excellent), .80 for dilation degree (excellent), .62 for dilation site (good) and finally .69 for dilation cause (good).

DISCUSSION AND CONCLUSIONS

MRP performed with the ultrafast breath-hold technique provides very good results in diagnosing urinary tract dilation, as well as the obstruction grade, site and cause, with results equal or even superior to those of non-breath-hold sequences. Ultrafast MRP lasts only 10 minutes, meaning it occupies the magnet shortly and costs less: it can be thus considered a routine alternative to conventional diagnostic imaging, especially ivp, in the evaluation of obstructive uropathy.

[Use of oral superparamagnetic contrast media in cholangiopancreatography with TSE single-shot magnetic resonance]

PURPOSE

To investigate the yield of an oral superparamagnetic contrast agent (Lumirem) in turbo spin echo (TSE) single-shot MR cholangiopancreatography (MRCP) in patients candidate to laparoscopic cholecystectomy.

MATERIAL AND METHODS

Thirty patients (mean age: 52.2 years) scheduled for laparoscopic cholecystectomy underwent MRCP with TSE single-shot sequences. To cover the biliary tree, thick-section TSE images were acquired according to the cross-sectional location of the biliary tract. Six 50-mm images progressively rotated by 30 degrees each were acquired during breath-holds. The precontrast images were obtained before the negative oral contrast agent was administered. The postcontrast images were acquired 10 minutes after oral contrast agent administration. Two observers made a qualitative evaluation on all images: the contrast enhancement was assessed comparing the pre- and postcontrast images of each examination on the basis of signal intensity in the stomach and duodenum, giving a score on a graduate scale. The greater yield of postcontrast images was validated by statistical analysis. The actual diagnostic improvement obtained with postcontrast images was validated for every single case.

RESULTS AND CONCLUSIONS

The greater yield of postcontrast images was statistically significant in the common bile and cystic ducts, but not in the gallbladder and Wirsung duct. Better images were obtained in 22/30 patients. The actual diagnostic improvement in the visualization of the common bile and cystic ducts was statistically significant in 7/30 patients. To conclude, administering an oral negative contrast agent improved image quality and the diagnostic yield. The agent was well tolerated and safe and we suggest its use in TSE single-shot MRCP of the patients candidate to laparoscopic cholecystectomy.

Relationships between neuroradiological and clinical features in apparently idiopathic hypopituitarism

In this study, perinatal history, postnatal auxological and clinical evolution and endocrine features were retrospectively evaluated in 49 children, adolescents and young adults with apparently idiopathic hypopituitarism. They were divided into two groups according to magnetic resonance images: 32 patients with isolated pituitary hypoplasia (group A) and 17 with pituitary stalk interruption syndrome (group B). The aim of the study was to assess whether these neuroradiological pictures are associated with specific endocrine and clinical patterns. No significant difference in terms of gestational age, intrauterine growth and rates of adverse perinatal events was found between the two groups. Clinical signs documenting the existence of pituitary dysfunction in utero or shortly after birth were either slightly (micropenis, cryptorchidism, cholestatic jaundice) or significantly (hypoglycemia) more frequent in patients in group B. Although diagnosis of hypopituitarism was made significantly earlier in patients in group B, height deficiency at diagnosis was similar in both groups. Endocrine investigations revealed a more severe and widespread impairment of pituitary function among those in group B. The main conclusion is that the postnatal clinical course is more severe when growth hormone deficiency is associated with pituitary stalk interruption syndrome than when the pituitary is only reduced in height, probably because of the more severe and widespread impairment of pituitary function in the former cases.

[Computerized tomography findings in benign diseases of the sphenoid sinus]

INTRODUCTION

Benign diseases of the sphenoid sinus can be classified as intrinsic, originating from the mucosa and sinus bone walls, and extrinsic, arising from adjacent structures. We analyze the CT features of both intrinsic and extrinsic benign sphenoid conditions and their diagnostic role and impact on treatment planning.

MATERIAL AND METHODS

We reviewed the CT scans of 75 patients with benign sphenoid sinus conditions from our 1993-96 series. The conditions were diagnosed at histology of the surgical specimen or from clinical findings and patient's history. Both axial scans, parallel to the orbitomeatal line, and coronal scans, perpendicular to the hard palate, were always acquired. The matrix was 512 x 512 and the FOV was appropriate. The different diseases were diagnosed based on the CT features of normal sinus bone walls or, conversely, wall thickening/thinning, focal erosions or bone destruction. The density of intra- and extrasinusal tissue and its contrast enhancement, intratissutal calcifications or bone fragments and changes in the sphenoethmoid recess were also studied.

RESULTS

Sinus bone walls were normal in 41/75 cases, focal/diffuse thinning was found in 12, focal interruption in 7 and thickening in 10. Intra- and perisinusal tissue with soft-tissue density was detected in 66/71 cases, with high density in 4 and low density in 1 case. Contrast enhancement of the pathologic tissue was found in 15 cases. Sphenoethmoid obliteration was demonstrated in 29 cases, with enlargement in 5 and reduction in 5.

DISCUSSION

Benign diseases of the sphenoid sinus are an uncommon finding. They are mainly due to chronic or recurrent inflammatory diseases, frequently associated with pansinusal involvement. Sphenoid sinus involvement can also be found in pathologic conditions originating from adjacent structures. We conclude that the accurate study of the intra- and extrasinusal soft tissue and bone walls permits to hypothesize the nature of a benign pathologic process, which has an impact on treatment planning. CT can be considered the technique of choice in the study of the sphenoid region.

[Comparisons of pulmonary and sinonasal lesions in patients with cystic fibrosis. Evaluation using computerized tomography]

INTRODUCTION

Cystic fibrosis is a recessive genetic systemic exocrinopathy caused by a variety of mutations in the cystic fibrosis transmembrane conductance regulator gene (CFTR). The disease is characterized by alterations of the secretions, which become thickened and viscous. Both the paranasal sinuses and the lung parenchyma are involved in all cases. The aim of this study was to assess a correlation between the rhinosinusal and lung parenchyma changes in cystic fibrosis patients.

MATERIAL AND METHODS

Eighteen patients (11 men and 7 women, age range: 8 to 22 years) were examined with chest HRCT and sinonasal low dose CT. Lung symptoms were found in all patients; 13 of them, also affected with rhinosinusal symptoms, had been examined with ENT and nasal endoscopy. The other 5 patients, without rhinosinusal symptoms and previously examined with ENT, were evaluated as control group. Chest CT was performed with the high-resolution technique, 2 mm slice thickness and 10 mm table feed. Rhinosinusal CT was performed with the low dose technique, acquiring contiguous 2-4 mm thickness coronal sections. The CT patterns were analyzed by two radiologists and scored as slight, medium and diffuse involvement of both districts.

RESULTS

No statistically significant correlation between lung and sinonasal damage was found in our study. Parenchymal lung involvement appeared more severe than sinonasal involvement in 14/18 patients. The retention of secretions in the paranasal sinuses, even if limited, was demonstrated in all symptomatic and asymptomatic patients.

CONCLUSIONS

The absence of correlation between pulmonary and sinonasal damage and more generally, the different severity of cystic fibrosis can be caused by different allele mutations of the cystic fibrosis transmembrane conductance regulator gene, the most frequent of which is Delta F-508.

[Significance of the circumferential involvement of the superior horn tip of the thyroid cartilage in pharyngo-laryngeal cancer]

The term "laryngopharyngeal carcinoma" indicates an advanced tumor involving both the supraglottic larynx and the pharynx in which the lesion origin may be difficult to assess. In 1981, Larsson et al. reported on the CT signs useful to distinguish the laryngeal/hypopharyngeal origin of advanced laryngopharyngeal carcinoma. We describe a new CT sign which may serve this purpose, namely the involvement of the thyroid cartilage superior horn tip. The thyroid cartilage superior horn, in fact, is involved early in the lesions originating in the pyriform sinus because of its close anatomic relationship with the posterolateral wall of the hypopharynx. MATERIALS AND METHODS. To assess the significance and specificity of this sign, we examined 15 patients with advanced laryngopharyngeal carcinoma with clinical, endoscopic and surgical evidence suggestive of tumors originating in the pyriform sinus. All CT examinations were performed with contiguous 4 mm slices before and after i.v. administration of iodinated contrast agents. Eighteen patients with surgically confirmed advanced supraglottic carcinoma were also examined.

RESULTS

The thyroid cartilage superior horn tip was involved only in 3/18 supraglottic carcinoma patients; transcommissural infiltration of the larynx, involving both pyriform sinuses, was found in 2 of these cases and extensive invasion of the whole thyroid cartilage and of the cricoid ring in 1 case.

CONCLUSIONS

The thyroid cartilage superior horn tip is a reliable sign of the pyriform sinus origin of advanced laryngopharyngeal cancer which is both sensitive (100%) and specific (83%). Moreover, this sign could play a major role because it represents, in most cases, the only and earliest sign of cartilage involvement. Finally, the encasement of the thyroid cartilage superior horn tip by abnormal tissue indicates tumor spread beyond the posterior pharyngeal wall. Therefore, these data can be very important for its early detection and useful for subsequent surgical planning.

Microsurgical excision of a primary isolated hypothalamic eosinophilic granuloma. Case report

Solitary focal eosinophilic granuloma (EG) is one element in the spectrum of diseases associated with Langerhans' cell histiocytosis (LCH). This report documents the occurrence of a primary isolated hypothalamic EG in a man who presented with diabetes insipidus and panhypopituitarism. His treatment consisted of complete microsurgical excision of the lesion. After a 13-month follow-up period, no residual tumor was evident on magnetic resonance imaging and no other lesions were present in peripheral tissues. This case is unique in several respects: 1) it is the third documented case of a primary isolated hypothalamic LCH granuloma diagnosed in a living patient; 2) it is the only known example of complete microsurgical excision of such a lesion in the hypothalamic region; and 3) it demonstrates the efficacy of direct surgery in this scenario, as compared with other treatment modalities such as biopsy and irradiation, suggesting that complete surgical excision may represent the treatment of choice for isolated intracerebral LCH granulomas, being curative in most instances. Also, the literature is reviewed for information about the diagnosis and treatment of this particular type of unifocal brain lesion.

[The angiogram sign in lung consolidation: what is its diagnostic value?]

The angiogram sign in chest CT is the demonstration of normally enhanced pulmonary branches within hypoattenuating lung parenchyma consolidation. In a retrospective review of the chest CT exams performed in a 2-year period, we identified the angiogram sign in 10 patients with lung consolidation; the diagnosis was central lung tumor with obstructive pneumonia in 4 patients, bronchioloalveolar carcinoma in 2 patients, postirradiation fibrosis in 1 patient, tuberculous pneumonia in 1 patient, lung lymphoma in 1 patient and metastasis from pancreatic tumor in 1 patient. The diagnosis was made with cytology and/or surgical specimen in 9 patients and with clinical-radiologic follow-up in 1 patient. The density, air and mucous bronchogram and the volume loss in the consolidated lung were also considered. The consolidated lung density was < 30 HU in 5 patients-one bronchioloalveolar carcinoma, one metastasis from pancreatic carcinoma and 3 obstructive pneumonia cases-, while it was > 30 HU in the extant 5 patients. The air bronchogram sign was observed in 4 cases-one bronchioloalveolar carcinoma, one metastasis, one postirradiation fibrosis and one lung lymphoma-, while a mucous bronchogram was observed in 3 patients with obstructive pneumonia. Lung volume was reduced only in 2 patients-one obstructive pneumonia and one postirradiation fibrosis. In our opinion, the CT angiogram sign must be considered a poorly specific sign, because it can be found in many pathologic processes, both benign and malignant. If associated with the other features of lung consolidation, the CT angiogram sign can help diagnose, together with clinical findings and the patient's history, the pathologic condition. Particularly, the angiogram sign within a hypoattenuated lung consolidation area can be found in obstructive pneumonia, while the angiogram sign within a hypoattenuated consolidation with an air bronchogram probably indicates a mucinous carcinoma with lipidic growth.

Therapeutic infiltration of the facet joint in minor intervertebral disease

SUMMARY

A CT-guided infiltration technique of the facet joints was employed on a group of 20 patients suffering from sciatica without any signs ofmorphostructural alteration of the facet joints, secondary to Minor Intervertebral Disease (MID). The typical flouroscopically guided intra-articular facet arthrography has been substituted by a CT-guided technique that privileges therapy rather than diagnosis. The study involved 20 patients between 29 and 57 years of age (average 44.5), of both sexes (16 females and four males). The average time which elapsed from onset of symptomatology was 9.5 months. At seven days after the first treatment subjective results were considered excellent by 11 patients (55%), good by one (5%) and satisfactory by one (5%). Six out of20 patients (30%) failed to gain any relief of symptoms. Only one patient (5%) had a worsening of pain. Clinical evaluation by the physician at the same time showed a good result in 11 patients (55%), satisfactory in two (10%). In six patients (30%) the symptomatology was unchanged. At 4 months the subjective results were excellent in three (15%), good in six (30%) and satisfactory in two (10%) . Nine (45%) had no positive results. The clinical examination was excellent in tWo (10%), good in seven (35%), satisfactory in two (10%) and without any relief of symptomatology in nine (45%). These results encourage the use of CT-guided infiltration that, together with the small amount of contrast medium injected into the joint space, make it a safe technique for patients, avoiding or reducing complications.

Visual outcome in children with congenital hemiplegia: correlation with MRI findings

Fourteen children with congenital hemiplegia were studied with a detailed assessment of various aspects of vision (linear acuity, stereopsis, visual fields) and MRI. The aim of this study was to evaluate the effect of a congenital lesion on visual function. The results showed a very high incidence (78%) of children who had abnormal results on at least one of the visual tests. Visual abnormalities were not correlated with the clinical severity of hemiplegia or with a specific pattern of lesion on MRI. Similarly no constant association could be found between visual structures (optic radiations and primary visual cortex) and visual function. Finally, our results would suggest that all the children with congenital hemiplegia need to be investigated irrespective of the clinical severity or of the type or the extent of the lesion. This would help to identify children with minor visual abnormalities which can affect everyday life performance.