Exoscopic Minimally Invasive Open-Door Laminoplasty for Cervical Myelopathy: A Technical Note and Preliminary Analysis of Clinical Outcomes during the Acute Postoperative Period.

Background/Objectives: Expansive open-door laminoplasty results in favorable clinical outcomes for cervical myelopathy. However, some postoperative complications associated with surgical invasiveness, such as axial neck pain and kyphosis, have not been resolved. The use of an exoscope, which is a recently introduced novel magnification tool, allows for traditional open-door laminoplasty with minimal invasiveness. Therefore, we propose the use of exoscopic minimally invasive open-door laminoplasty (exLAP) and present its clinical outcomes during the acute postoperative period. Methods: A total of 28 patients who underwent open-door laminoplasty at C3-C6 were reviewed. Of these patients, 17 underwent exLAP (group M) and 11 underwent conventional Hirabayashi open-door laminoplasty (group H). Outcomes were evaluated using numerical rating scale (NRS) scores for neck pain and the frequency of oral analgesic use from postoperative day 1 to 7. Results: The NRS score for neck pain was significantly lower for patients in group M than for those in group H. Conclusions: ExLAP is a novel, practical, and minimally invasive surgical technique that may alleviate the postoperative axial pain of patients with cervical myelopathy.

Behavioral and neural correlates of pareidolic illusions in dementia with Lewy bodies.

INTRODUCTION: Pareidolia, a form of visual illusions phenomenologically similar to complex visual hallucinations, is a phenomenon that is associated with visual hallucinations in dementia with Lewy bodies (DLB). This study aimed to identify commonalities and differences in behavioral and neural correlates between pareidolic illusions and visual hallucinations in DLB. METHODS: Forty-three patients with DLB underwent the scene pareidolia test, which evokes and measures pareidolic illusions, and standardized neuropsychological and behavioral assessments. Regional cerebral blood flow (rCBF) was measured by single-photon emission computed tomography. Factor analysis was performed to assess the relationships among pareidolic illusions, cognitive functions, and behavioral symptoms. Partial least squares correlation analysis was used to investigate the relationship between these symptoms and rCBF. RESULTS: Factor analysis yielded three behavior factors: the first factor (hallucinations/fluctuations) consisted of pareidolic illusions, visual hallucinations, and fluctuating cognition; the second factor (general cognitive function) consisted of general cognitive function and working memory; and the third factor (visual processing) consisted of visual processing and pareidolic illusions. Partial least squares correlation analysis identified two brain-behavior correlation patterns: (1) rCBF reduction in the frontal and perisylvian/periventricular regions was associated with lower general cognitive function and lower visual processing; and (2) rCBF reduction in the bilateral occipitotemporal cortex was associated with more severe hallucinations/fluctuations and lower visual processing. CONCLUSIONS: At the behavioral level, pareidolic illusions are associated with visual hallucinations, fluctuating cognition, and visual processing in DLB. At the neural level, pareidolic illusions may arise from the synergistic effects of global neuropathological changes and occipitotemporal cortical dysfunctions.

Mirror writing and cortical hypometabolism in Parkinson's disease.

Mirror writing (MW) is the production of individual letters, words, or word strings in the reverse direction. Parkinson's disease (PD) is a progressive neurodegenerative disorder, and high MW rates have been reported in patients with PD. Thus, the present study sought to identify the factors that cause MW in patients with PD. We examined the frequency of MW in patients with PD and investigated the area of the brain where such frequency inversely correlates with reduced regional cerebral metabolic rates of glucose (rCMRglc). We also examined whether this area satisfied the motor and visual monitoring hypotheses of MW that have been presented in previous studies. Thirty-six subjects with idiopathic PD and 23 healthy controls were included in the study. We asked the participants to write down words, numerals, and sentences from left to right using their dominant and non-dominant hands. Patients with PD underwent an 18F-fluorodeoxyglucose positron emission tomography scan to measure the rCMRglc. Neither the patients with PD nor the healthy subjects exhibited MW in the use of the right hand. In the use of the left hand, MW occurred in 15 of the 36 patients with PD, but in none of the healthy controls. The right intraparietal sulcus was identified as the area where rCMRglc was inversely correlated with the number of left-right reversed characters. Previous functional imaging studies have suggested that the right superior parietal cortex and intraparietal sulcus play an important role in recognizing left-right reversed letters. Therefore, dysfunction in the intraparietal sulcus may hinder the recognition of left-right reversed characters, resulting in MW. Consequently, our findings in patients with PD are consistent with the visual-monitoring hypothesis of MW.

Risk factors for unfavourable outcomes after shunt surgery in patients with idiopathic normal-pressure hydrocephalus.

A number of vascular risk factors (VRFs) have been reported to be associated with idiopathic normal-pressure hydrocephalus (iNPH), but it remains unclear whether these VRFs are related to patient outcomes after shunt surgery. Therefore, we investigated the risk factors for unfavourable outcomes after shunt surgery in iNPH patients using two samples from Tohoku University Hospital and from a multicentre prospective trial of lumboperitoneal (LP) shunt surgery for patients with iNPH (SINPHONI-2). We enrolled 158 iNPH patients. We compared the prevalence of VRFs and clinical measures between patients with favourable and unfavourable outcomes and identified predictors of unfavourable outcomes using multivariate logistic regression analyses. The presence of hypertension, longer disease duration, more severe urinary dysfunction, and a lower Evans' index were predictors of unfavourable outcomes after shunt surgery. In addition, hypertension and longer disease duration were also predictors in patients with independent walking, and a lower Evans' index was the only predictor in patients who needed assistance to walk or could not walk. Our findings indicate that hypertension is the only VRF related to unfavourable outcomes after shunt surgery in iNPH patients. Larger-scale studies are needed to elucidate the reason why hypertension can affect the irreversibility of symptoms after shunt placement.

Case Report: Semantic Variant Primary Progressive Aphasia With Impaired Verbal Word Discrimination.

Some patients with primary progressive aphasia (PPA) present with various types of hearing deficits. Research on the auditory function and speech sounds in PPA, including temporal, phonemic, and prosodic processing, revealed impairment in some of these auditory processes. Many patients with PPA who present with impaired word recognition subsequently developed non-fluent variant PPA. Herein, we present a patient with semantic variant PPA (svPPA) who demonstrated impaired verbal word discrimination. Audiological examinations revealed normal auditory brainstem responses and slightly impaired pure-tone perception. By contrast, verbal word discrimination and monosyllable identification were impaired, and temporal auditory acuity deteriorated. Analyses of brain magnetic resonance images revealed a significant decrease in the gray matter volume in bilateral superior temporal areas, predominantly on the left, compared with those of patients with typical svPPA, which appeared to be associated with impaired word recognition in our patient.

Improvement in callosal disconnection syndrome with recovery of callosal connectivity.

Recent advancements in radiological techniques have enabled the observation of the topographic distribution of the human corpus callosum. However, its functional connectivity remains to be elucidated. The symptoms of callosal disconnection syndrome (CDS) can potentially reveal the functional connections between the cerebral hemispheres. Herein, we report a patient with CDS, whose callosal lesion was restricted to the posterior midbody, isthmus, and an anterior part of the dorsal splenium. A 53-year-old right-handed woman demonstrated CDS following cerebral infarction associated with subarachnoid hemorrhage. She exhibited CDS including ideomotor apraxia, and tactile anomia with the left hand, cross-replication of hand postures, cross-localization of the fingers, and constructional impairment with the right hand. Six months after onset, the left-handed ideomotor apraxia on imitation improved, but that to command did not, which indicated the difference in the nature of the transcallosal connections between ideomotor apraxia on imitation and ideomotor apraxia to command. Longitudinal CDS observation and corpus callosum tractography will prove useful in expanding our understanding of the nature of the organization of interhemispheric information transference.

Conscious Hemiasomatognosia with No Somatosensory Disturbance Other Than a Unique Problem in Tactile Localization.

Conscious hemiasomatognosia is a disorder of the bodily self, involving subjective symptom where patients feel as if their whole body or part of one side has disappeared. Somatosensory disturbance is considered an essential component of conscious hemiasomatognosia. We herein report a 64-year-old man with conscious hemiasomatognosia of the right arm that developed after a left parietotemporal infarction, without any somatosensory disturbance except for a unique tactile localization problem. His response to the tactile localization test suggested impaired recognition of the positional relationship of his right arm relative to the entire body but normal recognition of positional relationships within the arm.

"Semantic variant primary progressive aphasia" due to comorbidity of Lewy body disease and a previous cerebral venous infarction in the left anterior temporal lobe: A case report.

Primary progressive aphasia (PPA) is a neurological syndrome characterized by progressive language impairment. Various neurodegenerative disorders cause PPA. Dementia with Lewy bodies (DLB) is one known cause of PPA, and little is known about this association. Almost all published cases of PPA associated with DLB are the logopenic variant of PPA. Here, we describe the novel case of a patient with DLB presenting clinical features of the semantic variant PPA (svPPA). A 75-year-old woman was referred to our hospital with a 2-year history of progressive anomia and amnesia. Two months before admission, she had been experiencing visual hallucinations, and at the age of 60 years, she had venous infarction in the left temporal lobe, which she recovered from without any residual symptoms. Upon admission to our hospital, she displayed anomia, impaired single-word comprehension, and surface dyslexia with preserved repetition and speech production. These symptoms met the criteria for the diagnosis of svPPA. 123I-ioflupane single-photon emission computed tomography and 123I-meta-iodobenzylguanidine myocardial scintigraphy indicated DLB. Thus, she was administered donepezil, and this dramatically improved her symptoms. We hypothesize that the combination of DLB with the previous asymptomatic venous thrombosis in the left temporal lobe may have contributed to the "svPPA" in this patient. In conclusion, we show that PPA associated with DLB could be treated with donepezil, and we suggest that donepezil should be pursued as a treatment option for PPA.

Echolalia in patients with primary progressive aphasia.

OBJECTIVE: This study aimed to examine echolalia and its related symptoms and brain lesions in primary progressive aphasia (PPA). METHODS: Forty-five patients with PPA were included: 19 nonfluent/agrammatic variant PPA (nfvPPA), 5 semantic variant PPA, 7 logopenic variant PPA, and 14 unclassified PPA patients. We detected echolalia in unstructured conversations. An evaluation of language function and the presence of parkinsonism, grasp reflex, imitation behaviour, and disinhibition were assessed. We also measured regional cerebral blood flow (rCBF) using single-photon emission computed tomography. RESULTS: Echolalia was observed in 12 nfvPPA and 2 unclassified PPA patients. All patients showed mitigated echolalia. We compared nfvPPA patients with echolalia (echolalia group) to those without echolalia (non-echolalia group). The median age of the echolalia group was significantly lower than that of the non-echolalia group, and the echolalia group showed a significantly worse auditory comprehension performance than the non-echolalia group. In contrast, the performance of repetition tasks was not different between the two groups. The prevalence of imitation behaviour in the echolalia group was significantly higher than that in the non-echolalia group. The rCBFs in the bilateral pre-supplementary motor area and bilateral middle cingulate cortex in the echolalia group were significantly lower than those in the non-echolalia group. CONCLUSIONS: These findings suggest that echolalia is characteristic of nfvPPA patients with impaired comprehension. Reduced inhibition of the medial frontal cortex with release activity of the anterior perisylvian area account for the emergence of echolalia.

Logopenic aphasia due to Lewy body disease dramatically improved with donepezil.

•Pathological basis of primary progressive aphasia is heterogeneous.•Logopenic primary progressive aphasia can precede dementia with Lewy bodies (DLB).•Cholinesterase inhibitor can improve logopenic aphasia with DLB.

Leg Muscle Strength After Lateral Interbody Fusion Surgery Recovers Over Time After Temporary Muscle Weakness.

STUDY DESIGN: Case-control study. OBJECTIVE: The objective of this study was to reveal the changes of leg muscle strength after lateral interbody fusion (LIF). SUMMARY OF BACKGROUND DATA: Muscle trauma and damage to intermuscular nerves due to dissection of the psoas are recognized perioperative complications of LIF. Although reduced leg strength is temporary in many cases, the underlying changes have not been studied in detail. METHODS: Leg muscle strength was measured quantitatively before LIF surgery and 1 week, 2 weeks, 3 weeks, 4 weeks, 8 weeks, and 12 weeks after surgery (n=38). Reduced muscle strength was defined as <80% of the preoperative measurement. The psoas position (PP%) was calculated from axial T2-weighted magnetic resonance images and compared with the degree of psoas and quadriceps muscle strength reduction at 1 week after surgery on the approach side. Twenty cases that underwent a posterior lumbar approach (posterior group) acted as controls. RESULTS: The proportion of patients with reduced psoas muscle strength 1 week after LIF was 60.5% on the approach side and 39.5% on the healthy side, versus 30.0% in the posterior group. The corresponding results for the quadriceps were 34.2%, 39.5%, and 25.0%, respectively. All cases had strength improvement on the approach side by 12 weeks postsurgery in the psoas and by 4 weeks postsurgery for the quadriceps. Psoas muscle strength and quadriceps strength at 1 week after surgery were correlated (ρ=0.57, P<0.001). There was a low inverse correlation between PP% and quadriceps strength at 1 week (ρ=-0.31, P<0.001). CONCLUSIONS: Muscle strength declined in both the psoas and quadriceps muscle groups after LIF; however, the effect was temporary and strength recovered over time. Reduced postoperative quadriceps muscle strength may relate the position of the psoas muscle via increased irritation of the lumbar plexus during the splitting maneuver.

Negative mood invites psychotic false perception in dementia.

BACKGROUND: There is increasing evidence for predictive coding theories of psychosis, which state that hallucinations arise from abnormal perceptual priors or biases. However, psychological processes that foster abnormal priors/biases in patients suffering hallucinations have been largely unexplored. The widely recognized relationship between affective disorders and psychosis suggests a role for mood and emotion. METHODS: Thirty-six patients with dementia with Lewy bodies (DLB), a representative condition associated with psychosis of neurological origin, and 12 patients with Alzheimer's disease (AD) were enrolled. After an experimental mood induction, the participants underwent the pareidolia test, in which visual hallucination-like illusions were evoked and measured. RESULTS: In DLB patients, the number of pareidolic illusions was doubled under negative mood compared to that under neutral mood. In AD patients, there was no significant difference in the number of pareidolic responses between negative and neutral mood conditions. A signal detection theory analysis demonstrated that the observed affective modulation of pareidolic illusions was mediated through heightened perceptual bias, not sensory deterioration. CONCLUSIONS: The current findings demonstrated that abnormal perceptual priors in psychotic false perception have an affective nature, which we suggest are a type of cognitive feeling that arises in association with perception and cognition.

Effect of three-dimensional rotational deformity correction in surgery for adult degenerative scoliosis using lumbar lateral interbody fusion and posterior pedicle screw fixation.

INTRODUCTION: Corrective surgery for adult degenerative scoliosis using lateral interbody fusion (LIF) and additional posterior fixation is an efficient procedure. However, it is unclear how this procedure affects rotational deformity correction. Therefore, the goal of the present study was to use three-dimensional (3D) images, taken during surgery, to investigate rotational deformity correction in the treatment of adult degenerative scoliosis using LIF and posterior fixation using a pedicle screw system. METHODS: The subjects were 12 females who were treated using LIF and posterior fixation for adult degenerative scoliosis. The patients had a mean age of 72 (65-76) years. 3D images were acquired before surgery, after LIF, and after additional posterior fixation. Rotational angles of the upper vertebra with respect to the lower vertebra of each fixed segment were measured in 3 planes. Correction factors for rotational deformity were investigated after LIF and additional posterior fixation. RESULTS: There were significant improvements in radiographical parameters for global spinal balance. The correction angles per segment were 4.7° for lateral bending, 6.9° for lordosis, and 4.5° for axial rotation. LIF was responsible for correction of four-fifths of lateral bending and axial rotation, and two-thirds of lordotic changes. CONCLUSIONS: Lateral bending, axial rotational deformities, and lordosis were primarily corrected by LIF. Further lordosis correction was achieved using additional posterior fixation. These results indicate that corrective surgery for adult degenerative scoliosis using these procedures is effective for rotational deformity correction and leads to an ideal global spinal alignment.

Prevention of neurological complications using a neural monitoring system with a finger electrode in the extreme lateral interbody fusion approach.

OBJECTIVE Extreme lateral interbody fusion (XLIF) is a minimally disruptive surgical procedure that uses a lateral approach. There is, however, concern about the development of neurological complications when this approach is used, particularly at the L4-5 level. The authors performed a prospective study of the effects of a new neural monitoring system using a finger electrode to prevent neurological complications in patients treated with XLIF and compared the results to results obtained in historical controls. METHODS The study group comprised 36 patients (12 male and 24 female) who underwent XLIF for lumbar spine degenerative spondylolisthesis or lumbar spine degenerative scoliosis at L4-5 or a lower level. Using preoperative axial MR images obtained at the mid-height of the disc at the treated level, we calculated the psoas position value (PP%) by dividing the distance from the posterior border of the vertebral disc to the posterior border of the psoas major muscle by the anteroposterior diameter of the vertebral disc. During the operation, the psoas major muscle was dissected using an index finger fitted with a finger electrode, and threshold values of the dilator were recorded before and after dissection. Eighteen cases in which patients had undergone the same procedure for the same indications but without use of the finger electrode served as historical controls. Baseline clinical and demographic characteristics, PP values, clinical results, and neurological complications were compared between the 2 groups. RESULTS The mean PP% values in the control and finger electrode groups were 17.5% and 20.1%, respectively (no significant difference). However, 6 patients in the finger electrode group had a rising psoas sign with PP% values of 50% or higher. The mean threshold value before dissection in the finger electrode group was 13.1 ± 5.9 mA, and this was significantly increased to 19.0 ± 1.5 mA after dissection (p < 0.001). A strong negative correlation was found between PP% and threshold values before dissection, but there was no correlation with threshold values after dissection. The thresholds after dissection improved to 11 mA or higher in all patients. There were no serious neurological complications in any patient, but there was a significantly lower incidence of transient neurological symptoms in the finger electrode group (7 [38%] of 18 cases vs 5 [14%] of 36 cases, p = 0.047). CONCLUSIONS The new neural monitoring system using a finger electrode may be useful to prevent XLIF-induced neurological complications.

Clinical characteristics of idiopathic normal pressure hydrocephalus with Lewy body diseases.

BACKGROUND: Comorbidity of idiopathic normal pressure hydrocephalus and neurodegenerative diseases presents a diagnostic challenge. The aim of this study was to elucidate the clinical features of iNPH patients who are possibly comorbid with Lewy body diseases. METHODS: In this study, we retrospectively analyzed the records of consecutive 127 patients with definite idiopathic normal pressure hydrocephalus. (123)I-Metaiodobenzylguanidine myocardial scintigraphy was undertaken to 21 patients with idiopathic normal pressure hydrocephalus because of suspicion for comorbid Lewy body diseases. RESULTS: As a result, 7 of the 21 patients with idiopathic normal pressure hydrocephalus exhibited cardiac sympathetic abnormality. Idiopathic normal pressure hydrocephalus patients with cardiac sympathetic dysfunction had the constellation of clinical findings, such as younger onset, less severe urinary dysfunction, kinesie paradoxale, and cogwheel rigidity. CONCLUSIONS: Our results suggested that comorbidity of idiopathic normal pressure hydrocephalus and Lewy body diseases are not rare condition and careful screening for potentially-curative surgery is important especially in atypical cases.

Amyloid deposits and response to shunt surgery in idiopathic normal-pressure hydrocephalus.

OBJECTIVES: In previous studies, patients with idiopathic normal-pressure hydrocephalus (iNPH) occasionally showed Alzheimer's pathology in frontal lobe cortical biopsy during cerebrospinal fluid shunt surgery or intracranial pressure monitoring. In clinical practice, the differential diagnosis of iNPH from Alzheimer's disease (AD) can be problematic, particularly because some iNPH cases exhibit AD comorbidity. In this study, we evaluated amyloid deposition in the brains of patients with iNPH before shunt surgery, and investigated the association between brain amyloid deposits and clinical improvement following the surgery. MATERIALS & METHODS: Amyloid imaging was performed in patients with iNPH or AD and also in healthy control subjects by using positron emission tomography (PET) and a radiolabeled pharmaceutical compound, (11)C-BF227. Using the cerebellar hemispheres as reference regions, the standard uptake value ratio (SUVR) of the neocortex was estimated and used as an index for amyloid deposition. In patients with iNPH, clinical symptoms were assessed before shunt surgery and 3 months after surgery. RESULTS: Five of the 10 patients with iNPH had neocortical SUVRs that were as high as those of AD subjects, whereas the SUVRs of the 5 patients were as low as those of healthy controls. A significant inverse correlation between neocortical SUVRs and cognitive improvements after shunt surgery was observed in iNPH. CONCLUSIONS: The amount of amyloid deposits ranges widely in the brains of patients with iNPH and is associated with the degree of cognitive improvement after shunt surgery.

Validity study of the standing test for imbalance and disequilibrium (SIDE): Is the amount of body sway in adopted postures consistent with item order?

The standing test for imbalance and disequilibrium (SIDE) is a discriminative measure developed for the purpose of identifying balance deficits that may cause falls. The purpose of the present study was to determine the validity of the sequence of postures used in SIDE. Subjects comprised 30 men with a mean (±standard deviation) age of 21.9±3.11 years (range 19-32 years) and 30 women with a mean age of 20.7±1.24 years (range 19-23 years). Center of pressure (COP) was measured using a stabilometer recording for 30s with a 20-Hz sampling frequency. The measurement postures that were similar to postures adopted in the SIDE were: standing with feet 20cm apart; standing with legs close and the insides of both feet touching; two tandem standing positions (with the dominant foot forward and with the non-dominant foot forward); and two single-leg standing positions (on the dominant foot and on the non-dominant foot). We calculated total path length and envelopment area of sway from the COP data. Statistical differences in means were determined using the Tukey-Kramer multiple comparison test. Results indicate that the orders of total path length and envelopment areas of sway in each posture were consistent with the item order of SIDE. Significant differences existed between the means of total path length and envelopment areas of sway in each posture (p<0.05), with the exception of both tandem standing positions and both one-leg standing positions. The item order of SIDE appears to show concurrent validity in terms of the amount of body sway in the adopted postures.

Anatomical assessment of the vastus medialis oblique muscle in patients with osteoarthritis of the knee.

Minimally invasive total knee arthroplasty requires subluxation of patella laterally without eversion. The anatomy of the vastus medialis oblique muscle (VMO), which affects the surgical exposure of minimally invasive total knee arthroplasty, was investigated. There was no significant difference between men and women with respect to any parameter. The average fiber angle relative to the rectus femoris muscle was 52.9 degrees on anteroposterior view and 49.7 degrees on lateral view. The average insertion height and the distal portion of VMO belly were 17.3% and 38.4% of the patella length from the upper pole of patella, respectively. Female patients had lower VMO attachment and VMO belly, and a significant sex difference was demonstrated. All patients had attachments beneath the upper pole of the patella.

Utility of delayed gadolinium-enhanced MRI (dGEMRIC) for qualitative evaluation of articular cartilage of patellofemoral joint.

Delayed gadolinium-enhanced MRI of cartilage (dGEMRIC) was used for the measurement of relative proteoglycan depletion of articular cartilage in the patellofemoral (PF) joint following a proprietary protocol, which was compared with the X-ray images, proton density weighted MR images (PDWI) and arthroscopic findings. The study examined 30 knees. The ages ranged from 16 to 74 (average 40.3) years. The Gd-DTPA(2-)containing contrast medium was used in a single dose. The subjects were made to exercise the knee joint for 10 min; and MR images were taken 2 h after intravenous injection of contrast medium. T1-calculated images were produced and the region of interest (ROI) was set as follows. (1) ROI1: entire articular cartilage in a slice through the center of the patella. (2) ROI2: low signal region in T1-calculated images, which were set in a blind fashion by two observers. (3) ROI3: articular cartilage on one side that includes ROI2 where low signal region were detected (medial or lateral). ROI3 was set to examine the contrast of ROI2 with surrounding articular cartilage. The average T1 values of ROI1 was 393.5+/-33.6 ms for radiographic grade 0 and 361.3+/-11.1 ms for grade I, which showed a significant difference (P=0.036). The T1 value of ROI2 was 351.6+/-28.2 ms for grade I, 361.9+/-38.3 ms for grade II, 362.1+/-67.7 ms for grade III, and 297.8+/-54.1 ms for grade IV according to arthroscopic Outerbridge classification. All cases, that demonstrated decrease of T1 values on dGEMRIC (ROI2), showed abnormal arthroscopic or direct viewing findings. The ratio (ROI3/ROI2) in cases of only slight damage classified as Outerbridge grade I (6 cases) was an average of 1.04+/-0.02 and was 1.0 or greater in all cases, thereby indicating well-defined contrast with the surrounding cartilage. The diagnosis of damage in articular cartilage was possible in all 16 cases with radiographic K-L grade I on dGEMRIC, while the intensity changes were not found in 10 of 16 cases on PDWI. The dGEMRIC with a single-dose would be useful on a diagnosis of the area demonstrating early relative proteoglycan depletion in the articular cartilage of the PF joint prior to any discernible changes in the subchondral bone on X-ray images and exceeds to plain MR images for examining deterioration of articular cartilage.