Initial data-element selection for the evaluation of picture archiving and communication system performance

The completely new, hospital-wide picture archiving and communication system (PACS) now being implemented at Osaka University Hospital is described elsewhere in this issue. This paper lists the many studies of the department and hospital that were performed before the PACS for the purpose of identifying data elements for use in evaluating a PACS system. A second purpose of the initial data-element collection was to assist in the overall Osaka University PACS design. Selected studies from this work are presented here.

A comparison of conventional screen-film radiography and hard copy of computed radiography in full and two-thirds sizes in detection of interstitial lung disease

This study examined whether hard-copy radiographs produced from computed radiography (CR) images show the subtle interstitial pulmonary disease equally well to conventional screen-film radiographs, because a digital radiography should be chosen for introduction of the digital picture archiving and communication system (PACS) for the new Osaka University Hospital. Eleven radiologists examined 20 abnormal and 20 control chest radiographs presented in each of three groups: conventional screen-film radiographs and two sizes of hard-copy radiographs made from CR images. This study of digital image quality of chest examinations found that some findings on conventional screen-film radiography images are not reproduced by current CR (2,000 x 2,000 x 10 bits in matrix), especially when the experienced radiologists were observed. This finding suggested improvements are needed in CR before CR of chest should fully replace conventional screen-film radiography.

Methenamine-silver staining: a simple and sensitive staining method for senile plaques and neurofibrillary tangles

An improved methenamine-silver impregnation method is presented which exhibits sensitivity for amyloid substances comparable to that of anti-beta protein immunostaining. In optimally treated sections, this technique stained both beta-amyloid deposits and neurofibrillary tangles, which are known to have a beta-pleated structure. This simple procedure allows a large number of sections to be stained for routine examination.

The delta-crystallin enhancer-binding protein delta EF1 is a repressor of E2-box-mediated gene activation

The repressor delta EF1 was discovered by its action on the DC5 fragment of the lens-specific delta 1-crystallin enhancer. C-proximal zinc fingers of delta EF1 were found responsible for binding to the DC5 fragment and had specificity to CACCT as revealed by selection of high-affinity binding sequences from a random oligonucleotide pool. CACCT is present not only in DC5 but also in the E2 box (CACCTG) elements which are the binding sites of various basic helix-loop-helix activators and also the target of an unidentified repressor, raising the possibility that delta EF1 accounts for the E2 box repressor activity. delta EF1 competed with E47 for binding to an E2 box sequence in vitro. In lymphoid cells, endogenous delta EF1 activity as a repressor was detectable, and exogenous delta EF1 repressed immunoglobulin kappa enhancer by binding to the kappa E2 site. Moreover, delta EF1 repressed MyoD-dependent activation of the muscle creatine kinase enhancer and MyoD-induced myogenesis of 10T1/2 cells. Thus, delta EF1 counteracts basic helix-loop-helix activators through binding site competition and fulfills the conditions of the E2 box repressor. In embryonic tissues, the most prominent site of delta EF1 expression is the myotome. Myotomal expression as well as the above results argues for a significant contribution of delta EF1 in regulation of embryonic myogenesis through the modulation of the actions of MyoD family proteins.

[Toxicity studies of paclitaxel. (II)--One-month intermittent intravenous toxicity in rats]

Paclitaxel, an antineoplastic agent, was intravenously given to Crj:CD (SD) rats of both sexes at 0 (saline), 0 (vehicle), 1.0 (low dose), 3.3 (intermediate dose) and 10.0 (high dose) mg/kg at five-day interval over one-month period (6 times in total) to investigate its repeated dose toxicity and the reversibility of toxic effects. The results obtained are summarized as follows: 1. Decreased activity with prone position was observed for high dose and vehicle groups, and alopecia was seen for many high dose rats. Body weight gain and food intake were suppressed for high and intermediate dose groups. No deaths occurred. 2. Red blood cell count, hemoglobin, hematocrit, white blood cell count, relative neutrophil count, platelet count and reticulocyte count were decreased for high dose groups. Red blood cells count was also decreased for intermediate dose groups. 3. Thymic atrophy, splenic hematopoiesis, bone marrow hypoplasia, testicular atrophy with suppression of spermatogenesis and tubular atrophy, and epididymal atrophy were observed for high dose rats. 4. Above-described changes excluding the findings on the testis and epididymis for high dose rats were shown to be generally reversible. Based on these results, the no-toxic effect dose of paclitaxel was estimated to be 1.0 mg/kg in rats under this study condition.

[Reproductive and developmental toxicity studies of paclitaxel. (I)--Intravenous administration to rats prior to and in the early stages of pregnancy]

Paclitaxel, an antineoplastic agent, was administered intravenously to Crj: CD (SD) rats daily at dose levels of 0 (saline and vehicle), 0.1, 0.3 and 1.0 mg/kg for 63 days prior to mating and during the mating period in males, and for 14 days prior to mating and during the mating period as well as day 0 to day 7 of gestation in females. Results were as follows: 1. Body weight gains were shown a tendency to hasten in vehicle-treated male rats associated with the increased food consumption. However, the vehicle-treated group had no effect in the other parameters that were measured in this study when compared to the saline-treated group. 2. 1.0 mg/kg paclitaxel caused suppression of the body weight gains accompanied by the decreased food consumption in either male or female rats. 3. Adrenal and ovarian weights were decreased in 1.0 mg/kg dams at term. 4. The fertility indices in both sexes of 1.0 mg/kg were lower than the saline-treated group. However, the copulation indices in both sexes in 1.0 mg/kg rats were comparable to those of the saline-treated group. 5. Decreases in the number of corpora lutea, implantations and live fetuses or increases in the number of empty implantation sites and total embryo-fetal deaths were observed in 1.0 mg/kg dams. However, the fetal weights, crown-rump distances and tail lengths in live fetuses were not affected by paclitaxel treatment. Based on the reproductive and developmental indices, the no toxic-effect dose level of paclitaxel is 0.3 mg/kg/day for parent animals and their fetuses.

[Toxicity studies of paclitaxel. (I)--Single dose intravenous toxicity in rats]

Paclitaxel, an antineoplastic agent, was given to Crj: CD (SD) rats of both sexes at 38, 50, 65 and 85 mg/kg by single intravenous administration to investigate its acute toxicity. The results obtained are summarized as follows: 1. Tachypnea and decreased activity with prone position were noted for vehicle and all paclitaxel groups, and alopecia for all paclitaxel groups. 2. Deaths occurred for one out of 5 males and 2 out of 5 females at 85 mg/kg. One female died of respiratory insufficiency induced by vehicle on Day 0. One female and one male died of the systemic toxicity of paclitaxel such as hypoplasia of the bone marrow and lymphoid depletion of lymphatic organs on Days 6 and 12, respectively. 3. On Days 4 and 5, all paclitaxel groups showed decreases of reticulocyte and white blood cell counts, as well as decrease of differential count of neutrophils. These changes were generally recovered by a week after dosing. 4. Histopathological examinations revealed atrophy of the thymic medulla, hypoplasia of the bone marrow and lymphoid depletion of the spleen for a few males at 85 mg/kg, and hypospermatogenesis and tubular atrophy of the testes for all paclitaxel groups. Based on these results, 85 mg/kg of paclitaxel was lethal to rats, and hematopoietic, lymphoid and male reproductive systems were primarily affected under this condition.

[Toxicity studies of paclitaxel. (III)--Six-month intermittent intravenous toxicity in rats]

Paclitaxel, an antineoplastic agent, was intravenously given to Crj:CD (SD) rats of both sexes at 0 (saline), 0 (vehicle), 0.3 (low dose), 1.0 (intermediate dose) and 3.3 (high dose) mg/kg at seven-day interval over a six-month period (total of 27 doses) to investigate its repeated dose toxicity. The results obtained are summarized as follows: 1. No deaths occurred in this study. Vehicle-related salivation was seen for some high dose and vehicle control rats. Soiling of the perigenital region was observed for some high dose females. 2. Red blood cell count, hemoglobin, hematocrit and white blood cell count were decreased for high dose rats. Reticulocyte count was increased and relative neutrophil count was decreased for high dose males. 3. Relative erythroid and myeloid cell count were decreased for high dose rats in bone marrow smear examinations. 4. Bone marrow hypoplasia and splenic hemosiderosis were observed for high dose rats, and thymic atrophy and lymphoid depletion were seen for some high dose males. Based on the these results, the no-toxic effect dose of paclitaxel was estimated to be 1.0 mg/kg in rats under this study condition.

[Reproductive and developmental toxicity studies of paclitaxel. (III)--Intravenous administration to rats during the perinatal and lactation periods]

Paclitaxel, an antineoplastic agent, was administered intravenously to pregnant Crj: CD (SD) rats daily at dose levels of 0 (saline and vehicle), 0.1, 0.3 and 1.0 mg/kg from day 17 of gestation to postpartum day 21. Results were as follows: 1. The vehicle-treated group had no effect in any of the parameters that were measured in this study when compared to the saline-treated group. 2. 1.0 mg/kg paclitaxel caused suppression of the body weight gains associated with the decreased food consumption in F0 dams during the lactation period. 3. Thymic, heart and uterine weights were reduced in 1.0 mg/kg F0 dams at completion of the lactation period. In addition, thymic atrophy was observed for 1.0 mg/kg F0 dams macroscopically. 4. Paclitaxel did not alter the delivery status of F0 dams or birth, viability and weaning indices in F1 pups. 5. The days required for presence of hair, incisor eruption and testicular descent were statistically delayed in 1.0 mg/kg F1 rats. 6. The latency time for olfactory orientation was prolonged in 1.0 mg/kg F1 rats on postnatal day 15. Further, the positive response rates for air righting were reduced in 1.0 mg/kg F1 rats from postnatal day 17 to day 20. 7. 1.0 mg/kg paclitaxel caused suppression of the body weight gains in male F1 rats from postnatal week 1 to week 12. Though body weight gains were decreased in 1.0 mg/kg female F1 rats from postnatal week 1 to week 7, there were no significant differences between dosed animals and saline-treated animals regarding the body weight gains and food consumption during the gestation period. 8. Paclitaxel did not affect the learning ability and memory, spontaneous motor activity or emotionality in F1 rats. 9. The reproductive performance in both male and female F1 rats were not affected by paclitaxel. 10. Splenic weights were reduced in 1.0 mg/kg male and female F1 rats at weaning. Furthermore, liver weights were decreased in 1.0 mg/kg male F1 rats after mating. 11. No influence on prenatal development was observed for F2 fetuses even at the highest dose level of paclitaxel. Based on the reproductive and developmental indices, the no toxic-effect dose level of paclitaxel is 1.0 mg/kg/day and 0.3 mg/kg/day for dams (F0) and their offspring (F1), respectively.

[Irritability study of paclitaxel in rabbit ear vein]

The vascular irritability of paclitaxel at concentrations of 0.6 and 1.2 mg/ml was examined using the rabbit ear vein by a single intravenous drip in comparison with its vehicle consisting of ethanol and Cremophor, and physiological saline. The results were as follows: 1. Slight to moderate congestion was macroscopically observed around some injection sites of the retroauricular veins infused by paclitaxel, the vehicle and saline. Its incidence and severity caused by paclitaxel was not so much different from that caused by the vehicle or saline. 2. Histopathological findings at the injection sites of the rabbits treated with paclitaxel consisted of vascular and perivascular changes, as well as alterations of the dermis and epidermis. These changes were severer than those brought by saline, and dose-dependent in their incidence and severity. Moreover, the lesions caused by paclitaxel at a concentration of 1.2 mg/ml were correspondent to those caused by the vehicle. Based on these results, the microscopic examinations suggested that the vascular irritability of paclitaxel might be attributable to administration of the vehicle.

[Reproductive and developmental toxicity studies of paclitaxel. (II)--Intravenous administration to rats during the fetal organogenesis]

Paclitaxel, an antineoplastic agent, was administered intravenously to pregnant Crj: CD (SD) rats daily at dose levels of 0 (saline and vehicle), 0.15, 0.3 and 0.6 mg/kg from day 7 to day 17 of gestation. Results were as follows: 1. The ossification of hyoid bodies was retarded in F1 fetuses by the vehicle. However, the vehicle-treated group had no effect in the other parameters that were measured in this study when compared to the saline-treated group. 2. Body weight gains and food consumption in F0 dams were not affected by paclitaxel during the gestation and lactation periods. 3. Paclitaxel failed to affect the organ weights in F0 dams. 4. Paclitaxel did not alter the prenatal development in F1 fetuses. 5. External, internal and skeletal malformations were not induced by paclitaxel. Further, paclitaxel did not affect the skeletal variations and ossification processes. 6. Paclitaxel did not alter the delivery status of F0 dams or viability and weaning indices in F1 pups. 7. The day required for presence of hair was significantly delayed in 0.6 mg/kg F1 pups at paclitaxel. However, the days required for pinnae detachment, incisor eruption, eye opening, testicular descent and vaginal opening were not affected by paclitaxel. 8. No effects on body weight gains or food consumption were observed in both male and female F1 rats. 9. Paclitaxel did not alter the developmental behavior, learning ability and memory, spontaneous motor activity or emotionality in F1 rats. 10. The reproductive performance in both male and female F1 rats were not affected by paclitaxel. 11. Paclitaxel did not alter the organ weights in both male and female F1 rats. 12. No influence on prenatal development was observed for F2 fetuses even at the highest dose level of paclitaxel. Based on the reproductive and developmental indices, the no toxic-effect dose level of paclitaxel is 0.6 mg/kg/day and 0.3 mg/kg/day for dams (F0) and their offspring (F1), respectively.

Interpretation of subtle interstitial lung abnormalities: conventional versus film-digitized radiography

PURPOSE

To evaluate the reliability of film-digitized radiography in detection of subtle interstitial lung abnormalities.

MATERIALS AND METHODS

The differences in interpretation of conventional screen-film (SF) and film-digitized (FD) radiographs obtained in 80 patients were studied. Forty patients with subtle interstitial lung abnormalities and 40 patients with no lung abnormalities were selected. SF radiographs of all patients were digitized (spatial resolution, 0.175 mm; 2,000 x 2,000 pixels; 10 bits). Five chest radiologists and five residents evaluated the images with a five-level scale of confidence. Results were evaluated with receiver operating characteristic techniques.

RESULTS

For the entire group, no statistically significant differences in performance were found between SF and FD radiographs. Chest radiologists performed better on SF radiographs (P = .003). For residents, no statistically significant differences were observed between the modalities.

CONCLUSION

FD radiographs may be inadequate compared with SF radiographs in the diagnosis of subtle interstitial lung abnormalities.

Lens-specific activity of the chicken delta 1-crystallin enhancer in the mouse

A lens-specific enhancer was identified in the third intron of the chicken delta 1-crystallin gene by analysis based on transient transfection of primary-cultured cells. To assess the significance of this enhancer's activity in embryonic lens cells during development, tkCAT gene carrying the enhancer was introduced into mouse embryos utilizing ES (embryonic stem) cell-mediated gene transfer. In the undifferentiated culture condition, ES lines with enhancer-carrying tkCAT did not express any significant level of CAT (chloramphenicol acetyltransferase). However, when the ES cells were injected into a blastocyst and allowed to differentiate into various somatic cells of an embryo, CAT expression was observed exclusively in lens, and the expression was dependent upon the delta 1-crystallin enhancer. We concluded that the delta 1-crystallin enhancer alone is sufficient for eliciting lens-specific gene expression in developing mouse embryos and that the mechanism of lens-specific regulation effected by the delta 1-crystallin enhancer is conserved between the chicken and the mouse.

PACS in Osaka University Hospital

To develop the hospital information system, the radiological information system, and the picture archiving and communication system for our new hospital, we analysed the data volume at each step of the flow in our present film-based system. After that, we used a small PACS, and it indicated the problems in it. From the analysis of the data volume of the film-based system, it was found out that digital data should be compressed, and prefetching techniques should be employed for digital PACS. Several types of display terminals had been proved to be necessary for different purposes. An RIS connection was thought to be obligatory to avoid incorrect input of ID on the image. Image input terminals should have edit functions for easy recognition of the image information. Taking account of these requirements for digital PACS, we are developing an actual total PACS.

Image quality of digital chest radiography: evaluation of subtle interstitial lung abnormalities (preliminary study)

To evaluate the image quality of storage phosphor radiography (SR) for diagnosing subtle interstitial lung abnormalities, we studied the differences between conventional screen-film radiography (FR) and SR in 38 patients. Nineteen patients had subtle interstitial lung abnormalities and the others had normal chests. Two formats of hard copies were used for SR; a full-size SR (14 x 14 inches, 0.2-mm pixel size) and a minified SR (9 x 9 inches, 0.13-mm pixel size). Readings were carried out by 14 readers (7 chest radiologists and 7 residents). The area under the receiver operating characteristic curve was used to evaluate the results. For the 14 readers no significant differences in observer performance were observed among the three image sets (FR, full-size SR, minified SR), while for the seven chest radiologists significant differences were observed between FR and the two formats of SR. The best perceptual accuracy was obtained with FR as evaluated by the seven chest radiologists. In conclusion, while overall performance with digital and conventional radiographs was almost the same as far as diagnosing subtle interstitial lung abnormalities, significant differences between FR and SR were found by chest radiologists. Critically important information may be lost in commercially available SR.

Technology assessment of PACS in Osaka University Hospital

This paper describes a methodology of PACS technology assessment and gives examples of the results of measurement of 24 items of PACS-related situations of image diagnosis systems in Osaka University Hospital before a PACS is installed. These data are to be compared with the data which will be measured after PACS is installed in the new Osaka University Hospital, in order to complete our technology assessment. We propose common variables, units, and conditions of measurement, in order to establish a standard method of data comparison between before and after PACS installation in hospitals at large. We designed our PACS taking technology assessment into account. We do not stop the technology assessment at the efficacy evaluation, because PACS must be more than a tool for radiological practice. We extend the technology assessment into the effectiveness evaluation, so that PACS is a part of radiological practice itself, and diagnostic accuracy, economy and efficiency are the results of PACS operation.

High-resolution CT and pulmonary function tests in collagen vascular disease: comparison with idiopathic pulmonary fibrosis

To estimate whether the lung abnormalities seen in collagen vascular diseases (CVD) were similar or distinct to those seen in idiopathic pulmonary fibrosis (IPF), and to ascertain whether the extent of the abnormalities on high-resolution CT (HRCT) correlated with pulmonary function, we reviewed HRCT findings and pulmonary function test results of 64 patients with either CVD (n = 55) or IPF (n = 9). Response to corticosteroid treatment was also evaluated in 20 of the 64. High incidence of honeycomb lesion was observed in IPF (9/9, 100%) and in progressive systemic sclerosis (PSS) (11/14, 79%). CVD, except for PSS, had a low incidence of honeycomb lesion (27%). On the other hand, incidence of ground-glass shadow in CVD (47/55, 85%) was the same as that in IPF (8/9, 89%). Diffusing capacity significantly correlated with the extent of all parenchymal abnormalities in all CVD and IPF, with honeycomb lesion in PSS, and with ground-glass shadow or air-space consolidation in CVD except for PSS (r < -0.7, P < 0.001). In all 15 cases in which corticosteroid therapy was effective, no honeycomb lesions were seen. Collagen vascular disease, except for PSS, had a different pattern of disease than IPF. The morphologic changes seen on HRCT correlated well with pulmonary function in CVD.

Murine chromosomal location of four class III POU transcription factors

A family of mouse genes encoding class III POU transcription factors consists of four members: Oct-6, Brn-2, Brn-1, and Brn-4. In accordance with mouse nomenclature, these loci have been designated Otf-6, Otf-7, Otf-8, and Otf-9, respectively. While the four genes share a highly conserved class III POU domain, the remaining regions are considerably diverged from each other. The POU domains of these transcription factors recognize the octamer-motif sequence and possess a similar DNA-binding specificity. Chromosomal mapping has demonstrated that the four genes are unlinked: Otf-6 is located on the distal region of chromosome 4, Otf-7 on the proximal region of chromosome 4, Otf-8 on chromosome 1, and Otf-9 on the X chromosome.

Delta-crystallin enhancer binding protein delta EF1 is a zinc finger-homeodomain protein implicated in postgastrulation embryogenesis

We investigated nuclear factors that bind to delta 1-crystallin enhancer core and regulate lens-specific transcription. A nuclear factor delta EF1, which binds to the essential element of the delta 1-crystallin enhancer core, was molecularly cloned from the chicken by a southwestern method. The protein organization of delta EF1 deduced from the cDNA sequence indicated that it has heterogeneous domains for DNA-binding, two widely separated zinc fingers and a homeodomain, analogous to Drosophila ZFH-1 protein. The C-terminal zinc fingers were found to be responsible for binding to the delta 1-crystallin enhancer core sequence. delta EF1 had proline-rich and acidic domains common to various transcriptional activators. During embryogenesis, delta EF1 expression was observed in the postgastrulation period in mesodermal tissues; initially, in the notochord, followed by somites, nephrotomes and other components. The expression level changed dynamically in a tissue, possibly reflecting the differentiation states of the constituent cells. Besides mesoderm, delta EF1 was expressed in the nervous system and the lens, but other ectodermal tissues and endoderm remained very low in delta EF1 expression. Cotransfection experiments indicated that this factor acts as a repressor of delta 1-crystallin enhancer. Possession of heterogeneous DNA-binding domains and its dynamic change of expression in embryogenesis strongly suggest that delta EF1 acts in multiple ways depending on the cell type and the gene under its regulation.

Focal organizing pneumonia: CT appearance

PURPOSE

To clarify the computed tomographic (CT) features of focal organizing pneumonia.

MATERIALS AND METHODS

The authors retrospectively studied CT scans of 18 patients with histologically proved focal organizing pneumonia. Chest radiographs in all 18 patients suggested bronchogenic carcinoma.

RESULTS

Seventeen of the 18 lesions (94%) had an irregular margin, 10 (56%) had satellite lesions, nine (50%) had a pleural tag, and nine (50%) had an air bronchogram. The pneumonia could be classified into three types: Type A (n = 5) was a small round mass (pleural tag, n = 4). Type B (n = 7) was an oval mass with broad contact with the pleura (satellite lesions and convergence of peripheral vessels, n = 6). Type C (n = 6) was an oval mass along the bronchovascular bundle (satellite lesions, n = 3; pleural tag, n = 4).

CONCLUSION

The CT features of focal organizing pneumonia show wide variation, and some type B and C lesions are suggestive of benign lesions. However, other lesions may be difficult to differentiate from bronchogenic carcinoma even with CT.

A mouse homologue of the Drosophila tumour-suppressor gene l(2)gl controlled by Hox-C8 in vivo

The homeobox is a 183-base-pair DNA sequence originally found in Drosophila segmentation and homeotic genes. In Drosophila, homeotic genes are clustered in the Antennapedia and Bithorax complexes, collectively called the homeotic gene complex (HOM-C). In the mouse genome, about 40 homeobox genes (Hox) are clustered in four chromosomal regions (Hox A to D). The Hox genes are arranged in the same order and have the same anteroposterior pattern of expression as their structural homologue in the HOM-C, suggesting that they control mouse pattern formation in the same way that HOM-C members do in Drosophila. Homeobox gene products are believed to be transcription factors that regulate expression of target genes. A few candidate target genes have been identified in Drosophila by various approaches but the Hox gene targets are poorly understood, mostly because of limitations in the available approaches. Here we identify several candidate Hox gene targets, including a mouse homologue of the Drosophila tumour-suppressor gene l(2)gl, by immunopurification of DNA sequences bound to a Hox protein in native chromatin.

Overlapping positive and negative regulatory elements determine lens-specific activity of the delta 1-crystallin enhancer

Lens-specific expression of the delta 1-crystallin gene is governed by an enhancer in the third intron, and the 30-bp-long DC5 fragment was found to be responsible for eliciting the lens-specific activity. Mutational analysis of the DC5 fragment identified two contiguous, interdependent positive elements and a negative element which overlaps the 3'-located positive element. Previously identified ubiquitous factors delta EF1 bound to the negative element and repressed the enhancer activity in nonlens cells. Mutation and cotransfection analyses indicated the existence of an activator which counteracts the action of delta EF1 in lens cells, probably through binding site competition. We also found a group of nuclear factors, collectively called delta EF2, which bound to the 5'-located positive element. delta EF2a and -b were the major species in lens cells, whereas delta EF2c and -d predominated in nonlens cells. These delta EF2 proteins probably cooperate with factors bound to the 3'-located element in activation in lens cells and repression in nonlens cells. delta EF2 proteins also bound to a promoter sequence of the gamma F-crystallin gene, suggesting that delta EF2 proteins are involved in lens-specific regulation of various crystallin classes.

Diagnosis of coronoid process hyperplasia by three-dimensional computed tomographic imaging

Three-dimensional (3D) CT imaging was performed on three cases (one unilateral, two bilateral) of coronoid process hyperplasia. This technique displayed the impingement of the enlarged coronoid process on an exostosis on the lower border of the malar bone. In addition, a small concavity was found on the inner surface of the malar bone that was not displayed by other imaging modalities. The 3D images were useful in planning surgical treatment. In cases of limitation of opening, finding a malar exostosis on conventional radiographs such as a Water's view should suggest the presence of coronoid process hyperplasia even if the impingement cannot be demonstrated.