Evaluation of cartilage surface injuries using 3D-double echo steady state (3D-DESS): effect of changing flip angle from 40° to 90°

BACKGROUND

In magnetic resonance imaging (MRI) with 3D-double-echo steady-state (3D-DESS) sequences, the cartilage-synovial fluid contrast is reported to be better with a flip angle of 90° than with the conventional flip angle of 40°, and the detection rate of knee cartilage injury may be improved.

PURPOSE

To compare the diagnostic performance and certainty of diagnosis with 3D-DESS images made using two flip angle settings, 40° and 90°, for knee cartilage surface lesions of Grade 2 or above confirmed by arthroscopy.

MATERIAL AND METHODS

Images were obtained with 3D-DESS flip angles of 40° and 90° at 1.0T in 13 consecutive patients (2 men, 11 women, age range 18-68 years) evaluated for superficial cartilage injury by arthroscopy. Two radiologists classified the presence or absence of cartilage damage of ≥Grade 2 as 'positive (p)' or 'negative (n)', respectively. The rate of agreement with arthroscopic diagnosis was then examined, and the diagnostic performance compared. Diagnostic confidence was assessed scoring the presence or absence of cartilage damage into three categories: 3 = can diagnose with absolute confidence; 2 = can diagnose with a level of certainty as probably present or probably absent; and 1 = cannot make a diagnosis.

RESULTS

In a comparison of the rate of agreement between diagnosis by 3D-DESS images and arthroscopy, the rate of agreement was significantly higher and diagnostic performance was better in 90° images for the medial femoral condyle only. Diagnostic confidence was significantly better with 90° flip angle images than with 40° flip angle images for all six cartilage surfaces.

CONCLUSION

In evaluating knee cartilage surface lesions with 3D-DESS sequences, a flip angle setting of 90° is more effective than the conventional setting of 40°.

Optimization of the number of selectable channels for spine phased array coils for transverse imaging

PURPOSE

The aim of this study was to investigate whether the signal-to-noise ratio (SNR) in transverse images acquired from spine phased array coils is improved by deactivating coils distant from the imaging region and to identify the optimum coil settings.

MATERIALS AND METHODS

Ten healthy volunteers (five men, five women; average age 38 years) underwent transverse magnetic resonance imaging (MRI) of the cervical spine using four to one channels of a four-channel phased array coil for cervical imaging. The SNR of cerebrospinal fluid (CSF), spinal cord, muscle tissue, intervertebral disc, vertebral body, and prevertebral soft tissue was measured for each coil combination.

RESULTS

In all measured regions, the SNR was the highest for images acquired using two coils; the SNR was significantly higher for two coils than for four coils in CSF, spinal cord, muscle tissue, intervertebral disc, vertebral body, and prevertebral soft tissue (P < 0.001, P = 0.019, P < 0.0001, P = 0.014, P = 0.010, P < 0.001).

CONCLUSION

Deactivating two of the four coils used for sagittal sections, meaning that two coils are active, resulted in improved SNR for transverse images. Selecting the optimum number and combination of coils for each imaging cross section may enable acquisition of images with a better SNR.

Rice and perfluorocarbon liquid pads: comparison of fat suppression effects

BACKGROUND

With the chemical shift selective (CHESS) method, lingering fat signals remain because of the effects of nonuniformity in the magnetic field. One method to reduce this phenomenon is the use of pads filled with rice (rice pad), but the improvement in fat suppression effects with rice pads, as compared with conventional perfluorocarbon liquid pads, remains unclear.

PURPOSE

To investigate whether rice pads are superior to perfluorocarbon liquid pads in improving fat suppression effects in magnetic resonance imaging (MRI) examination of the knee.

MATERIAL AND METHODS

Subjects were 10 healthy volunteers (5 men, 5 women; aged 20-45 years), from whom images taken using the CHESS methods were collected. Two images were taken for each subject; one with a rice pad placed under the knee and the knee flexed, and the other with a perfluorocarbon liquid pad placed under the knee and the knee flexed. Images were visually assessed by one radiologist and one radiologic technologist. Kendall's W and Wilcoxon signed rank test were used for statistical comparisons.

RESULTS

Of the 20 evaluations made by the 2 observers, scores for images obtained with the rice pad were higher than those with the perfluorocarbon liquid pad in 18 cases, while the scores were equal in 2 cases. Images with the rice pad were not inferior in any cases. The mean score for visual assessment was 4.65 for the rice pad and 3.0 for the perfluorocarbon liquid pad. The rice pad was thus confirmed to be superior to the perfluorocarbon liquid pad (P=0.0039).

CONCLUSION

The rice pad exhibited better performance in improving the fat suppression effect. Thus, the rice pad is a superior product that is inexpensive and simple to use.

Rice pads: novel devices for homogeneous fat suppression in the knee

BACKGROUND

In magnetic resonance imaging (MRI) of the knee joint, when imaging the knee in a flexed position using the chemical-shift-selective (CHESS) method, lingering fat signals in the popliteal region are sometimes seen.

PURPOSE

To investigate whether a pad filled with rice (rice pad) placed in the popliteal space is effective in eliminating the lingering fat signals in MR images of the flexed knee, based on the hypothesis that the use of a rice pad would improve the fat suppression effect.

MATERIAL AND METHODS

Subjects were 10 healthy volunteers (five males, five females; age, 20-45 years) from whom images were taken using CHESS. Images were obtained with: 1) the knee extended and nothing placed underneath; 2) the knee bent with a sponge placed underneath; and 3) the knee bent with a rice pad placed underneath. The effectiveness of suppressing fat signals was visually assessed by one radiologist and one radiological technologist.

RESULTS

The fat suppression effect in images obtained with the knee extended was good. In contrast, the images made with a sponge under the knee had conspicuous lingering fat signals for nearly all subjects. In the images made with a rice pad under the knee, a uniformly good fat signal suppression effect was seen in all patients, and the assessment score was far higher than that with the sponge pillow (P<0.001).

CONCLUSION

Lingering fat signals were suppressed with the use of a rice pad, and fat-suppressed images of the knee joint using CHESS were found to be improved.

Three-dimensional double-echo steady-state (3D-DESS) magnetic resonance imaging of the knee: contrast optimization by adjusting flip angle

BACKGROUND

The three-dimensional double-echo steady-state (3D-DESS) sequence is being used to investigate sequence parameters for the assessment of knee cartilage by magnetic resonance imaging (MRI). With the flip angle (FA) values that are commonly used, contrast between cartilage and synovial fluid may be too low to delineate minor lesions of the cartilage surface.

PURPOSE

To investigate the value of FA maximizing contrast between cartilage and synovial fluid using the 3D-DESS sequence.

MATERIAL AND METHODS

In 10 healthy volunteers (five men, five women; age range 23-48 years), 3D-DESS imaging was performed to capture median sagittal sections of the knee by adjusting FA from 10 degrees to 90 degrees. Cartilage-synovial fluid contrast-to-noise ratio (CNR) was measured to determine the value of FA maximizing CNR. Water-excitation pulse was used to suppress fat signals. MRI was performed at 1.0 T using a circular polarization flex coil.

RESULTS

Cartilage-synovial fluid CNR was highest with 90 degrees FA, yielding images with good contrast between cartilage and synovial fluid.

CONCLUSION

Simply by increasing FA to 90 degrees in 3D-DESS imaging, the contrast between cartilage and synovial fluid increased substantially. Subtle cartilage lesions may thus be detectable using 3D-DESS sequences.

Association of fatty liver with increased ratio of visceral to subcutaneous adipose tissue in obese men

We studied the association of fatty liver with subcutaneous and visceral obesity in 46 male and 36 female patients with body mass index (BMI) over 22 kg/m2. The correlation coefficient between the ratio of the visceral adipose tissue to the subcutaneous adipose tissue (V/S) and the computed tomography (CT) number of the liver was -0.299 (P < 0.05) and that between the V/S ratio and the ratio of the CT number of the liver to that of the spleen (CT-L/CT-S) was -0.335 (P < 0.05) in the males. Partial correlation analysis after making correction for BMI showed an increased correlation coefficient of -0.485 (P < 0.05) between the V/S ratio and the CT-L/CT-S ratio in the males. The odds ratio in the males for CT-L/CT-S below 1.0 and V/S above 1.0 was 3.25 with a 95% confidence interval of 1.02 to 9.39. No such association between the V/S ratio and the CT-L/CT-S ratio was present in the female patients. Multiple regression analysis with serum level of alanine aminotransferase, a marker of fatty liver, as an independent variable revealed a partial regression coefficient of -17.7 for CT-L/CT-S (P < 0.05) in the males and -21.7 (P < 0.05) in the females, validating the CT-L/CT-S ratio as an index of fatty liver. The results indicate the association of fatty liver as determined by the CT-L/CT-S ratio with visceral obesity in males.

Pepleomycin-induced pneumonitis resulting in death

Two cases of fatal pneumonitis induced by pepleomycin, a new antitumour antibiotic analogous to bleomycin, are described. In the first case, the patient received radiation in combination with intra-arterial administration of pepleomycin to a total dose of 100 mg. for the treatment of an epidermoid carcinoma of the maxilla. The pulmonary changes were noted two weeks after cessation of the chemotherapy and the patient died of pulmonary insufficiency despite intensive therapy with antibiotics and a steroid. The other case with an epidermoid carcinoma of the cheek and oropharynx was treated by radiation and pepleomycin given to a total dose of 205 mg. Pepleomycin was replaced by predonin soon after bilateral shadows were noticed on a chest radiograph, but the patient died of pneumonitis 10 months later. Various factors which may affect the development of pulmonary toxicity by pepleomycin are discussed.

Marsupialization as a possible diagnostic aid in cystic ameloblastoma. Case report

Two cases of cystic ameloblastoma are described in which the diagnosis was established after marsupialization. Although the clinical and radiographic findings strongly suggested the diagnosis of ameloblastoma, the initial incisional biopsy specimens consisted of cystic walls lined with squamous epithelium which showed in both cases no evidence of ameloblastic proliferation. Marsupialization could be a diagnostic aid in these cases since relief of intracystic pressure may trigger regeneration of a solid mass of tumour in a monocystic ameloblastoma with cells possessing potentiality for spontaneous proliferation.

Bilateral Warthin's tumor: report of case and review of Japanese literature

A case of Warthin's tumor with bilateral and multiple involvement is described, along with a review of 104 cases reported in the Japanese literature. The tumor comprised 3.5% to 6.7% of all tumors in the parotid gland, which was affected in 96.2% of our cases. Bilateral or multiple involvement was observed in 17 cases. The incidence was approximately four times higher in males than in females, and 91.4% of the cases occurred between the fifth and eight decades of life, with a mean of 57.2 years. Onset of the initial symptoms had been disregarded for a few months to five years in 80% of the patients. All the tumors were treated surgically and diagnosed histologically as Warthin's tumor of a benign type with the exception of two cases.

Effects of sequential administration of bleomycin in combination with mitomycin C on squamous cell carcinoma of oral regions

A sequential administration of bleomycin in combination with mitomycin C was evaluated clinically and histologically in ten patients with squamous cell carcinoma of the oral region. The therapy was effective against seven primary lesions and one metastatic lesion with an evident tendency to remission, but was completely ineffective against recurrent carcinomas. Myelosuppression seemed to be a more important toxic effect than the bleomycin-induced pneumonitis. The mechanism of action of the therapy and indications in clinical application are discussed.

Experimental and clinical studies on differential diagnosis of bone diseases with nucleomedical procedures

This report is a study of the differential diagnosis of bone diseases using nucleomedical procedures. Experimental and clinical studies on the accumulation of 201Tl and 67Ga in bone inflammation and bone tumors were performed. Also, the degree of deposition of 99mTc-phosphorous compounds represented as a color difference was evaluated for a differentiation between malignant and benign diseases of the spine and shoulder. Uptake of 201Tl in inflammation of the spine and in tumor of the pelvis of rabbits was very low, while that of 67Ga was high. Uptake of 67Ga decreased gradually with lapse of time after the onset of inflammation. These experimental results agreed with clinical studies. The detectability of malignant tumors with 201Tl was inferior to that with 99mTc-label and 67Ga, although osteolytic lesions were occasionally 201Tl-positive. In terms of color range, the difference was 2 or less in spines of normal subjects and 3 or more in the metastatic bone disease and compression fracture. This difference was not statistically significant. Since 67Ga scan was occasionally negative in compression fracture, a differentiation was considered to be possible in such a case. A combined study of bone imaging with 99mTc-phosphorous compound including color difference, 67Ga imaging, bone-marrow imaging and radiography are considered to be helpful for the differentiation.

Changes in heart rate during administration of local anesthetics in neuropsychiatric patients

The effects on heart rate of injections of local anesthetics into the oral mucosa were studied in neuropsychiatric patients; these patients, in whom syncope had not occurred, had been hospitalized for a prolonged period. The heart rate in the neuropsychiatric patients decreased by only 3.9% in contrast to an average decrease of 12.6% in healthy adults. Diazepam was also effective in reducing the cardiac response. The lack of responsiveness in the trigeminal-vagal reflex may be a factor in protecting patients from syncope.

Basal cell nevus syndrome. A case report

An 11-year-old boy with multiple dentigerous cysts in the maxilla and mandible is described. Other findings seen in the face, plantar skin, skeletal system and oral cavity indicated the lesions to be due to the basal cell nevus syndrome. This was further confirmed by the presence of similar abnormalities in his father and brother.

Chemotherapy in the treatment of osteogenic sarcoma of the maxilla (case report)

A case of osteogenic sarcoma of the maxilla is described. The tumor was excised by a hemimaxillectomy but recurred in 3 months. The patient died 8 months after the initial onset of symptoms. Chemotherapy and radiation were ineffective with the exception of bleomycin, which caused necrosis of the tumour, with no apparent increase in growth, and a decrease of the serum alkaline phosphatase level to less than half of the maximum value. There was a close correlation between the fluctuating pattern of the serum alkaline phosphatase level and the growth and remission of the tumour during the entire course of treatment.

Experimental study on tumor affinity of 201T1-chloride

The tumor affinity of 201T1 was studied with normal and VX-2 cancer-bearing rabbits. 201T1 distribution in normal rabbit tissues was greatest in the kidney and heart muscle, followed by thyroid gland small intestine, spleen, lung, liver, bone marrow, bone, skeletal muscle, and blood, respectively. Accumulation into the thyroid varied greatly according to individuals. Generally, the taller the height of follicular cells, the greater was the affinity. Accumulation of 201T1 into the tumor transplanted into femoral muscle reached its maximum within 1 h after administration, and thereafter decreased gradually. When the tumor affinity was compared with that of 67Ga, the ratio of 67Ga accumulation to tissues (except blood) was greater than that of 201T1. Accumulation of 201T1 is significantly correlated to that of 42K, and the mechanism of 201T1-tumor affinity seems to be triggered by the acceleration of the potassium metabolism of a tumor. Accumulation into the inflammatory focus was greater with 67Ga as a ratio to muscle, while the ratio to blood was greater with 201T1.

An evaluation of hepatobiliary scintigraphy with 99mTc-pyridoxylideneisoleucine

From our experience with 30 cases, we conclude that 99mTc-PI is useful for assessment of hepatobiliary diseases and is much preferable to the 131I-labeled compounds.

Changes of heart rate during administration of local anesthetics in the oral region

In an attempt to clarify the mechanism of shock in dental patients, the effects on the heart rate of the injection of an anesthetic agent into the oral mucosa were studied. The heart rates of the subjects decreased by an average of 12.6% during infiltration anesthesia, which was greater than that induced by the mandibular block or breathholding. The response was completely blocked by general anesthesia and partially blocked by inhalation of nitrous oxide and oxygen or previous administration of atropine, indicating the possible participation of trigeminal-vagal reflex in producing these changes of heart rate.

[Experimental and clinical studies on the accuracy of geometry-independent counter]

For the purpose to conduct precise geometry-independent radioassay of large biological samples, the authors constructed an apparatus with the "peak+scatter" counting method slightly modified from that of Gibbs, et al. and studied its accuracy from the basic and clinical aspects. The apparatus, an opposed-head counter, consisted of two matched 2 x 2-in. NaI crystal detectors and photomultipliers that were connected in parallel to a pulse-height spectrometer. The crystal faces were separated by 54 cm. The detectors were enclosed in 5cm-thick shield built with lead and the sample chamber was a 15 cubic cm-box type of 3 mm-thick Lucite. A 13 cmphiX7.7 cm styrene topper container was used for the sample container. It was found that the relation of primary gamma energy of six radioisotopes and geometry-independent counting threshold turned out to be linear. The assay accuracy with 131I was about +/- 5% in fluid samples irrespective of its sizes (up to 500 ml) or homogeneity. In solid samples the accuracy approached that of fluid by the addition of water up to the height of it. The range, in which the activity could be measured within 5% error originating from statistical fluctuations or loss of counts due to instrument dead time, proved to be about 34 approximately .06 micronCi with 57Co in assay time of 10 min. On the basis of the basic investigations, the geometry-independent counting was used for the radioassay of stool and urine. Since the assay could be done simply up to a relatively large volume without need of material adjustment, it served well in the assay of urine and stool of clinical practice as well as in animal radioassay.