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Biomedical subjects

Seppo K Koskinen

Publications and source records attributed to Seppo K Koskinen.

15 recordsLinked to original sources

MRI of menisci repaired with bioabsorbable arrows.

OBJECTIVE: To analyze with conventional magnetic resonance imaging (MRI) the signal appearance of menisci repaired with bioabsorbable arrows. DESIGN AND PATIENTS: Forty-four patients with 47 meniscal tears treated with bioabsorbable arrows underwent follow-up conventional MRI examination. The time interval between the surgery and MRI varied from 5 to 67 months (mean 26 months). Twenty-six patients also had concurrent repair of torn anterior cruciate ligament. The following grades were used to classify meniscal signal intensity: (a) G0; low signal intensity on all sequences and regular configuration in every plane, (b) G1; increased signal intensity within the meniscus, not extending to the meniscal surface, (c) G2; increased signal intensity linear in shape, which may or may not communicate with the capsular margin of the meniscus, without extending to the meniscal surface, and (d) G3; increased signal intensity extending to the meniscal surface. RESULTS: Thirteen menisci (27.5%) had normal signal intensity, 13 menisci (27.5%) Grade 1 signal intensity, 9 menisci (19%) Grade 2 signal intensity and 12 menisci (26%) Grade 3 signal intensity. The time difference between operation and MRI was statistically significant between the G0 (36 months) and G3 groups (14 months; P = 0.0288). There was no statistical significance in different grades between medial and lateral meniscus or between patients with operated or intact ACL. On physical examination sixteen patients reported slight symptoms, seen evenly in each group. CONCLUSION: No difference was seen in different grades between patients with operated or intact ACL. The highest incidence of menisci with a Grade 3 signal was seen in patients where surgery was within the last 18 months.

Absorbable Implants↗

T1rho Dispersion profile of rat tissues in vitro at very low locking fields.

The purpose of this study was to show the T(1rho) dispersion profile in various rat tissues (liver, brain, spleen, kidney, heart and skeletal muscle) at low (0.1 T) B(0) field at very low locking field B1, starting from 10 microT. The T(1rho) dispersion profile showed a quite similar pattern in all tissues. The highest R(1rho) relaxation rates were seen in the liver and muscle followed by the heart, whereas the values for spleen, kidney and brain were rather similar. The greatest difference between R2 relaxation rate and R(1rho) relaxation rate at B1=10 microT was seen in the liver and muscle. The steepest slope for a dispersion curve was seen in the muscle. The value of T(1rho) approximately approached the value of T2 when the locking field B1 approached 0. Except for the liver, the calculated apparent relaxation rate R2' was slightly larger than the calculated one. The potential value of T(1rho) imaging is to combine high R1 contrast of low-field imaging with the high signal-to-noise ratio (SNR) of high static field imaging. T(1rho) relaxation and dispersion data presented in the current study help to optimize the rotating-frame MR imaging.

Animals↗

The incidence and distribution of burst fractures.

This study was conducted to assess occurrence and distribution of burst fractures as well as common accident mechanisms and the associated neurologic deficit. Using picture archiving and communications system, all emergency multidetector computed tomography studies over 34 months were retrieved and evaluated for burst fractures by two radiologists by consensus. Initial neurological findings were retrieved from patients' medical records. One hundred fifty-two patients (112 male) with a total of 169 burst fractures were found. In both genders, the incidence of burst fractures peaked at the thoracolumbar junction and between levels T5 and T8. In 10% of cases, more than one burst fracture was seen, thereof 53% on noncontiguous levels. Main accident mechanisms were falls, traffic, and sports. Neurological deficit was highest in patients with burst fractures of the cervical spine, independent of accident mechanism, and lowest in thoracolumbar junction fractures. Burst fractures occur frequently in high energy traumas and are most commonly associated with falling and traffic accidents. Multiple burst fractures occur in 10% of cases, half thereof on noncontiguous levels.

Adult↗

Diagnostic value of pelvic radiography in the initial trauma series in blunt trauma.

The purpose of the study was to evaluate the diagnostic value of pelvic radiography in the initial trauma series when compared to multidetector CT (MDCT) findings in serious blunt trauma. Inclusion criteria were blunt trauma and pelvic radiography in the initial trauma series, followed by a whole-body MDCT. A total of 1386 patients (874 male, 512 female, age 16-91 years, mean 41 years) met the inclusion criteria. Imaging studies were evaluated retrospectively by anatomical region and classified, when possible, using the Tile classification. Based on MDCT, a total of 629 injuries occurred in 226 (16%) of these 1386 patients. Radiography depicted 405 fractures in these 226 patients, giving an overall sensitivity of 55%. In 24 patients (11%) radiography was false-negatively normal. The sensitivity of radiography was mainly good in the anteroinferior parts of the pelvis, fair in the acetabulum and ileum, and poor in the posterior ring. By MDCT 141 (62%) patients were classified using the Tile classification and by radiography 133 patients (59%) were classified. MDCT and radiography showed the same type of pelvic injury in 72 patients (59%) and the subtype in 17 patients (14%). In 48 patients (40%) the pelvis was shown to be stable by radiography but unstable by MDCT. In conclusion, the sensitivity of pelvic radiography is low, and it is not reliable for determining if the pelvic injury is stable or not.

Adult↗

Radicular lower extremity pain as the first symptom of primary hyperparathyroidism.

Clinical symptoms of hyperparathyroidism are generally nausea, vomiting, fatigue, constipation, and hypotonicity of the muscles and ligaments; bone pain and tenderness are also seen but are more common in secondary hyperparathyroidism. We report a histologically confirmed case of a 28-year-old man whose sole symptom of primary hyperparathyroidism was lower extremity radicular pain due to a vertebral brown tumor. Magnetic resonance imaging demonstrated brown tumor to be hyperintense on T2-weighted and slightly hypointense on T1-weighted sequences; it showed intense contrast enhancement with gadolinium. Because brown tumors usually contain hemosiderin a short T2 should have been expected, but this was not seen in our case. Healing resulted in decreasing contrast enhancement on T1-weighted sequences and increasingly short T2. To our knowledge, this is the first report of a lumbar vertebral brown tumor associated with primary hyperparathyroidism.

Adenoma↗

Multidetector CT in shoulder fractures.

The aim of this study was to assess the multi-detector computed tomography (MDCT) findings in acute shoulder traumas compared to radiographic findings in patients referred to a level one trauma center. Two hundred and ten patients (128 male, 82 female, age 16-95 years, mean age 51.7 years) underwent shoulder MDCT due to acute trauma. Three main mechanisms of injury were established: falling (113 patients, 54%), traffic accidents (36 patients, 17%) and falling from a height (12 patients, 6%). Based on MDCT, a total of 311 fractures--152 in the scapula and 159 in the proximal humerus--occurred in 191 (91%) of the 210 patients. The two most common occult fractures were lesser tubercle and coracoid process fractures. In 20 (63%) of the patients with a comminuted fracture of proximal humerus the exact number of fracture fragments was underestimated in radiographs. MDCT with multiplanar reconstructions (MPR) is a recommended complementary examination in patients with complex proximal humerus fractures where the extent of the fractures and the position or origin of dislocated fragments is not clear on radiography. This may increase the accuracy of the fracture classification and reveal occult fractures in other parts of the shoulder.

Adolescent↗

Cortical activation during a spatiotemporal tactile comparison task.

Tactile sensory memory is needed to infer shape or motion from the spatiotemporal pattern of sensory input during manual exploration. Here we applied triplets of pressure pulses to the fingertips of subjects who were asked to respond when successive triplets were the same (COMPARE task) or when a particular stimulus was included in a triplet (CONTROL task). Stimulus sequences (30 s) alternated with rest blocks (30 s) and functional magnetic resonance images (fMRIs) were acquired in a 1.5-T scanner. During the COMPARE task, we found enhanced activation in inferior parietal cortex, supplementary motor area (SMA), and right dorsolateral prefrontal cortex (DLPFC). Activation of DLPFC is likely to be related to the attempt to memorize the stimulus sequences and activations of SMA and inferior parietal cortex to the analysis of temporospatial tactile patterns and, more generally, to guidance of haptic exploration. In addition, task-specific activation was seen in anterior cingulate gyrus, possibly related to the high mental effort required by the comparison task. Our rhythmic tactile stimulus as such, without any task-specific enhancement, activated also left cerebellum and (mainly left) putamen, supporting the idea that these structures are related to perception of temporal order of tactile stimuli.

Adult↗

Reconstruction of soft tissue after complicated calcaneal fractures.

A total of 35 flap reconstructions were done to cover exposed calcaneal bones in 31 patients. All patients had calcaneal fractures, 19 of which were primarily open. Soft tissue reconstruction for the closed fractures was indicated by a postoperative wound complication. A microvascular flap was used for reconstruction in 21 operations (gracilis, n = 11; anterolateral thigh, n = 5; rectus abdominis, n = 3; and latissimus dorsi, n = 2). A suralis neurocutaneous flap was used in eight, local muscle flaps in three, and local skin flaps in three cases. The mean follow-up time was 14 months (range 3 months-4 years). One suralis flap failed and was replaced by a latissimus dorsi flap. Necrosis of the edges that required revision affected three flaps. Deep infection developed in two patients and delayed wound healing in another four. During the follow-up the soft tissues healed in all patients and there were no signs of calcaneal osteitis. Flaps were considered too bulky in five patients. Soft tissues heal most rapidly with microvascular flaps. In the long term, gracilis muscle covered with free skin grafts gives a good contour to the foot. The suralis flap is reliable and gives a good final aesthetic outcome. Local muscles can be transposed for reconstruction in small defects.

Adolescent↗

Ankle and foot injuries: analysis of MDCT findings.

OBJECTIVE: The purpose of our study was to assess MDCT findings and the advantages of MDCT compared with radiography in patients referred to a level 1 trauma center for diagnostic evaluation of acute ankle and foot trauma. MATERIALS AND METHODS: During a period of 37 months, 388 patients underwent MDCT of the ankle and foot due to an acute trauma. Imaging studies (MDCT and radiography) were retrospectively reevaluated with respect to fracture location, fracture type, and mechanism of injury, and findings from the primary radiographs of the ankle and foot were compared with MDCT findings. RESULTS: Of the 388 patients, 344 (89%) had one or more fractures in the ankle or foot. A total of 517 fractures were found in all anatomic regions: ankle, calcaneus, talus, midfoot, and forefoot. The three most common occult fractures in the ankle not detected on primary radiography were isolated fractures of the posterior and medial malleolus and Tillaux fractures. The calcaneus was the most commonly fractured bone, and the sensitivity of radiography in the detection of calcaneal fractures was 87%. The sensitivity of radiography in the detection of talar fractures was 78%, whereas it was only 25-33% in the detection of midfoot fractures. A Lisfranc fracture-dislocation was not detected on primary radiography in five (24%) of 21 cases. The three main injury mechanisms were falling from a height (164 patients [48%]), a simple fall (68 patients [20%]), and a traffic accident (47 patients [14%]). CONCLUSION: In patients with injuries from high-energy polytrauma and in those with complex ankle and foot fractures, the sensitivity of radiography is only moderate to poor; in these cases, MDCT is recommended as the primary imaging technique.

Adolescent↗

Wrist injuries; diagnosis with multidetector CT.

The aim of the study was to assess acute-phase multidetector CT (MDCT) findings in wrist injuries. We retrieved all emergency room MDCT requests processed in the period from August 2000 to May 2003. All patients with a wrist injury who underwent MDCT initially were included. Imaging studies were evaluated in relation to injury mechanism, fracture location, and fracture type. A total of 6422 MDCT examinations were performed during this 34-month period, and 38 patients (24 male, 14 female, age range 21-73 years, mean age 40 years) met the inclusion criteria. MDCT revealed 56 fractures and 7 dislocations in 29 patients. In 9 patients (24%) MDCT findings were normal. Eleven patients (29%) underwent surgical procedures. The main injury mechanism was a fall (58%). In 33 cases the primary radiograph was available. Compared to primary radiographs, MDCT revealed 9 occult fractures, mainly in small carpal bones. In 14 cases a suspected fracture (of the scaphoid in 7 cases) was ruled out by MDCT. Due to high-quality two-dimensional reformatting, MDCT examinations were not dependent on the wrist's position in the CT gantry. In the comparison with radiography, MDCT detected occult fractures and ruled out suspected fractures, both mainly in the small carpal bones. High-quality two-dimensional reformats gave significant information about the fracture anatomy. MDCT provides fast and valuable information in assessing complex wrist fractures or when the primary radiograph is equivocal.

Adult↗

Spine fractures in falling accidents: analysis of multidetector CT findings.

The purpose of the present study was to assess incidence, fracture type, and location of spine fractures due to falls. All emergency room CT requests during a time period of 26 months were reviewed retrospectively. Patients who had fallen or jumped and were initially examined with multidetector CT (MDCT) were included. The MDCT studies were evaluated by two radiologists for trauma location, fracture type, and multiple level involvement. A total of 237 patients (184 males, 53 female, age range 16-86 years, mean age 42 years) met the inclusion criteria. A total of 203 vertebral fractures were seen in 127 patients. Burst fracture (n=78) was the most frequent type of trauma, usually located in the thoracolumbar junction (50%). Also, compression fracture (n=52) was most common in the thoracolumbar junction (39%). Posterior column fracture (n=52) was most frequently detected in the cervical spine (40%). Multiple-level spine fractures were seen in 41 (32%) of the injured patients, of which 12 (29%) had fractures at noncontinuous levels. With increasing height the overall incidence of fractures increased, and burst fractures and multiple level spine fractures became more frequent. Age had no effect on fracture type or location. Spine fractures due to falls are common. Burst fracture is the most common fracture type and most frequently seen in the thoracolumbar junction. Multiple-level fractures were seen in 32% of the cases, of which 29% were seen at noncontinuous levels. Serious spine fractures are seen in all falling height and age groups.

Accidental Falls↗

Occurrence of comminution (type IIA) in type II odontoid process fractures: a multi-slice CT study.

The classification of odontoid process fractures introduced by Anderson and D'Alonzo in 1974 has gained wide acceptance among researchers and clinicians. In type II fractures the injury is located in the base of the odontoid process. In 1988 Hadley et al. introduced a comminuted subtype of this fracture, type IIA. Since then several authors have recommended a more aggressive surgical approach in treatment of this subtype. However, only a few cases of comminuted type II fractures have been reported. The objective of this study is to assess the occurrence of comminution in type II fractures. Twenty-six type II fractures imaged by multislice CT were reviewed. Subtle comminution of the fracture was observed in 12 of the cases. We conclude that, when imaged by multislice CT, subtle comminution in type II odontoid fractures is seen more commonly than previously reported in the literature.

Journal Article↗

Serious horse-riding accidents: imaging findings and evaluation with multi-slice CT.

PURPOSE: To assess acute phase multi-slice CT findings in horse-riding accidents in patients referred to a level one trauma center. METHODS: Using PACS, we retrieved all CT requests during a time period of 19 months. Patients who had a horse-riding accident and were examined with multi-slice CT were included. The imaging findings of multi-slice CT were retrospectively evaluated by location and injury mechanism. RESULTS: Forty-six patients (3 male, 43 female, age 16-55 years, mean age 30) were assessed. The injuries we found were five head, three facial, 13 spine, five body, two pelvic, and three lower extremity trauma. Multiple injuries were seen in five (11%) patients. In 21 patients (46%) the initial multi-slice CT examination(s) was normal. Three main injury mechanisms were established; falling off a horse (72%), a horse kick (11%), and crushing injury caused by a falling horse (13%). Fifteen (33%) patients had serious injuries, one lethal and they were associated more frequently with falling off a horse. CONCLUSION: Serious injuries with horse riding accidents are not uncommon. In two thirds of patients, the injury mechanism was falling off a horse. Multiple injuries were seen in 11% of cases. In the acute phase, multi-slice CT provided fast and valuable information in assessing these injuries.

Journal Article↗