Human liver regeneration: hepatic energy economy is less efficient when the organ is diseased.

Recovery of liver cell mass following hepatectomy requires a metabolic compromise between differentiated function and organ regrowth. Clinical experience has shown that hepatic failure after resection is more common when the organ is diseased. We have evaluated intracellular hepatic biochemistry in patients with normal and cirrhotic livers undergoing partial hepatectomy, using 31-phosphorus magnetic resonance spectroscopy ((31)P MRS). Eighteen patients were studied, half with normal liver architecture (normal group, n = 9) and half with cirrhotic parenchyma (cirrhosis group, n = 9). Magnetic resonance examinations were performed preoperatively and on postoperative days 2, 4, 6, 14, and 28. Hepatic volume (estimated by magnetic resonance imaging [MRI]) and blood chemistries were measured at the same intervals. Following a comparable reduction in parenchymal volume, the cirrhotic group demonstrated a more sustained fall in adenosine triphosphate (ATP) energy state. Disturbance of membrane phospholipid metabolism and duration of acute-phase reaction were more marked when the liver was diseased. The pattern of derangement of hepatic function, however, was similar in the two groups. Overall, the recovery process was less efficient in the cirrhotic organ, and culminated in a diminished rate and extent of the regenerative response. These outcomes indicate that liver regeneration after partial hepatectomy involves modulation of hepatic energy economy in response to changing work demands. The efficiency of this process is influenced by the histopathologic state of the organ, and in turn governs the physiologic reserve. These findings may explain the mechanism of posthepatectomy liver failure, and offer a rational basis for the assessment of novel hepatic support strategies.

Correlation of ultrasonographic imaging of congenital muscular torticollis with clinical assessment in infants.

Congenital muscular torticollis (CMT) is a common problem affecting infants and children. There is a general lack of standard clinical classification or objective assessment methods. Ultrasonographic imaging of the sternomastoid muscle (SCM) has been carried out in a consecutive series of 436 infants less than 1 y old presenting with CMT over a 5-y period. All patients were classified into three clinical groups: postural torticollis, muscular torticollis and sternomastoid tumor. The severity of the torticollis was also expressed into four subgroups according to the degree of deficits in passive rotation of the neck. The ultrasonographic image of the affected SCM included the echogenicity, texture, motility, softness and the transverse and longitudinal extent of the involvement. The disturbance in the quantitative measurement of the transverse diameter of the lower and upper third of the SCM and the ratio of the measurement to the normal side was recorded. The qualitative and quantitative changes in the SCM image were found to correlate significantly with the clinical typing and severity of rotational deficits of the neck. Ultrasonographic imaging has important potential clinical application in helping the diagnosis, prognostication and monitoring of progress of CMT longitudinally.

Assessment of optic nerve compression in Graves' ophthalmopathy. The usefulness of a quick T1-weighted sequence.

PURPOSE: Diagnosis of optic nerve compression can be difficult in patients with equivocal clinical signs. We examined the usefulness of a quick coronal MR sequence performed at a predetermined plane as a screening tool for selecting patients at high risk of optic nerve compression. MATERIAL AND METHODS: Direct coronal images of the orbit were obtained in 37 patients with Graves' disease in a predetermined plane. The muscular indices (MI) of each orbit were calculated. Mann-Whitney U-Wilcoxon rank sum test was used to assess if there was any statistically significant difference between patients with and without signs of optic nerve compression. The ROC curve was used to identify a value useful for discriminating patients with a higher risk of developing optic nerve compression. RESULTS: There was a statistically significant difference (p<0.05) in the MI between patients with and without optic nerve compression. An MI of -0.48 had 100% sensitivity, 89% specificity and 91% accuracy in identifying patients with optic nerve compression. CONCLUSION. A quick coronal MR image obtained at the mid-orbital plane is useful in screening patients with Graves' disease for optic nerve compression.

Nodal shape (S/L) and its combination with size for assessment of cervical lymphadenopathy: which cut-off should be used?

The short axis to long axis (S/L) ratio is commonly used to assess cervical lymphadenopathy; however, the cut-off value used has been limited to 0.5. The accuracy of the combination of S/L ratio and nodal size has not been documented previously. We evaluated 1143 normal cervical nodes from 95 healthy subjects, and 1441 nodes from 290 patients with proven cervical lymphadenopathy. The optimum cut-off value of the S/L ratio was determined in different regions of the neck: submental (0.5), submandibular (0.7), parotid (0.5), upper cervical (0.4), middle cervical (0.3) and posterior triangle (0.4). In the submandibular and parotid regions, the combination of the S/L ratio and short axis shows substantial improvement in diagnostic accuracy when compared to the S/L ratio alone.

Magnetic resonance imaging and audiologic assessment of middle ear effusions in patients with nasopharyngeal carcinoma before radiation therapy.

OBJECTIVE: The aim of this study was to assess the performance of clinical methods, viz. otoscopy, pure-tone audiometry, and tympanometry in diagnosing middle ear effusions (MEEs) using magnetic resonance imaging as a reference standard. STUDY DESIGN: A retrospective study of 46 patients with newly diagnosed nasopharyngeal carcinoma was performed comparing clinical evaluation and audiometry results with magnetic resonance imaging findings obtained before radiation therapy. RESULTS: Twenty-two (25%) of the temporal bones imaged had both MEE and mastoid effusions, 24 (27%) had only middle ear fluid, and 29 (33%) had mastoid fluid alone. The sensitivity for tympanometry, audiometry, and otoscopy in detecting fluid in the middle ear was 96%, 92%, and 80%, respectively. Although tympanometry was most sensitive in diagnosing MEE, there was no statistically significant difference when comparing the overall accuracy of pure-tone audiometry air-bone gap and tympanometry (p = 0.7, chi-square test). Flat curve tympanograms (type B) only achieved a sensitivity of 45% but were of high specificity (92%). Forty-nine percent with negative pressure tympanograms (mean air pressures > -100 daPa) had no MEE. CONCLUSIONS: Using magnetic resonance imaging as a reference standard, tympanometry is the most sensitive audiologic test in detecting the presence of MEE. The overall accuracy of tympanometry, pure-tone audiometry air-bone gap, and otologic examination was, however, not significantly different.

Cervical assessment by magnetic resonance imaging--its relationship to gestational age and interval to delivery.

The aim of this cross-sectional study was to assess the uterine cervix in late pregnancy, using MRI, and to study its relationship to the gestational age and the time interval to delivery. 91 women with a singleton cephalic presenting fetus had MRI of the pelvis between 35 and 41 weeks. All had had one prior lower segment Caesarean section and no history of prior vaginal delivery. The cervical length, internal and external os diameter, cervical signal intensity and the angulation of the cervix with the cephalocaudal axis were measured on sagittal T2 weighted images and correlated with the gestational age and the interval from the MRI examination to delivery. It was found that the signal intensity of the cervical stroma increased with the gestational age. A higher signal intensity in the cervical stroma was associated with a shorter time interval to delivery. Deliveries after 40 weeks tended to occur more commonly in those with lower signal intensity in the cervical stroma and also in those with a smaller external os diameter. It is concluded that cervical softening as assessed on MRI correlated with gestational age and the time interval to delivery.

Ultrasound assessment of mild splenomegaly: spleen/kidney ratio.

BACKGROUND: Ultrasound may detect mild splenomegaly before it is clinically palpable. Knowledge of the normal range of spleen size in the population being examined is a prerequisite. Racial differences in splenic length could result in incorrect interpretation of splenic measurements. OBJECTIVE: To measure the normal values of splenic length in Hong Kong Chinese children and compare the results with Western data; to determine whether there is a constant ratio of the length of the spleen to the left kidney, which could be used to diagnose splenomegaly without reference to a nomogram. MATERIALS AND METHODS: Ultrasound was used to measure maximum splenic and left kidney length in 256 Chinese children to obtain normal values for spleen length and to determine the spleen/kidney ratio. Results. Splenic length in Chinese children is similar to Western children up to the age of about 15 years. The spleen/left kidney ratio is strikingly constant with a mean value of 1. Using 2 SD above the mean as a guide, the upper limit of normal for the spleen/kidney ratio is 1.25. CONCLUSION: Splenomegaly should be suspected in children if the spleen is more than 1.25 times longer than the adjacent kidney.

Ultrasound assessment of swallowing in malnourished disabled children.

Oral motor dysfunction is common in children with neurological impairment. Nutritional advice depends upon an accurate assessment of feeding potential in these cases. Videofluoroscopic assessment of oral motor function has been the accepted "gold standard" investigation for several years but has significant drawbacks, including the time constraints set by the use of ionizing radiation and the problems posed by the cumbersome equipment needed in mimicking the child's normal feeding situation. Ultrasonography (US) has been suggested as an alternative or additional investigation of oral motor function in children with neurological impairment. We prospectively evaluated a scoring system derived from US assessment of oral motor function in 32 malnourished disabled children with feeding problems by comparing them with a group of matched control children without neurological impairment. US imaging provided useful information with regard to the oral cavity and the soft tissue structures, capturing the salient features of tongue/hyoid/palate activity and bolus transport across the tongue and through the hypopharyngeal area. The mean percentage score obtained by US assessment of oral motor function in children with neurological impairment was 54.3 +/- 23.2 and from children without neurological impairment 91.9 +/- 12.7 (p < 0.0001). Scores for the oral and pharyngeal phases of swallowing were also very significantly lower than that in the control group, both phases being equally impaired in the disabled children. This study has demonstrated that a scoring system based on US assessment of different components of oral motor activity detects statistically significant differences in the feeding capabilities of children with neurological impairment.

Assessment of factors affecting palpability of breast masses using ultrasonography in Chinese women.

Five hundred and twenty-nine women with self-discovered or clinically palpable breast lumps had physical examination followed by high-resolution ultrasonographic examination of the breast. A total of 482 palpable and 146 nonpalpable masses were discovered by ultrasonography. The median values of the breast stromal, premammary, and retromammary fat thickness measurements were 1.3 cm, 0.1 cm, and 0.1 cm, respectively. The median depths of the lesions and the distance of the lesions from the pectoralis muscle were 0.5 cm and 0.2 cm, respectively. The median size of all breast masses was 1.5 cm. These measurements (of the tissue characteristics of the breast, location of the breast mass, and size of the breast lesion) were correlated with palpability or nonpalpability of the breast lesions. Multivariate logistic regression performed for all breast masses showed the only significant factors affecting palpability to be the size (anteroposterior and transverse diameters) and the depth of a breast mass. This is expressed by the following equation: [formula: see text] where z = -0.8759 + 0.9691 (g) + 2.2770 (e)-1.5332 (d), and d represents depth of lesion from the cutaneous surface and e and g represent anteroposterior and transverse diameters of the breast mass, respectively. The nature of the breast tissue (i.e., the premammary fat, retromammary fat, or breast stromal thickness as determined by ultrasonography) does not affect palpability. This study would therefore strongly support the recommendation of breast self-examination, irrespective of breast structure.

Detection and assessment of intracranial aneurysms: value of CT angiography with shaded-surface display.

OBJECTIVE: The purpose of this study was to evaluate the efficacy of circle of Willis CT angiography with shaded-surface display in the detection and assessment of suspected intracranial aneurysms. MATERIALS AND METHODS: Twenty-three patients who had clinical or radiologic suspicion of intracranial aneurysms were studied prospectively with CT angiography and conventional angiography. The images were obtained and interpreted in a double-blind fashion by different radiologists. Conventional angiography, which was the reference standard in this study, diagnosed 17 aneurysms in 15 patients. The usefulness of the two types of images for surgical planning was evaluated by two neurosurgeons. RESULTS: No aneurysms were detected with either technique in eight patients. Both techniques showed 15 aneurysms in 14 patients. The maximum dimensions were less than 3.0 mm in three cases, 3.0-5.0 mm in four cases, and greater than 5.0 mm in eight cases. With conventional angiography used as the reference standard, CT angiography has one false-positive and two false-negative findings, resulting in a sensitivity of 88% (15/17) and a specificity of 89% (8/9). For 12 of 15 aneurysms, CT angiography was rated equal or superior to conventional angiography in depicting all aspects (shape, orientation, neck, and parent vessel) of the aneurysms. CONCLUSION: We were able to detect aneurysms of the circle of Willis as small as 2 mm in size. Using conventional angiography as the reference standard, CT angiography has a sensitivity of 88% and a specificity of 89% for the detection of aneurysms in the circle of Willis. In almost all cases, CT angiography was equal or superior to conventional angiography in characterizing the aneurysms for surgical planning.