Clinical outcomes of palliative self-expandable metal stent placement in right- and left-sided malignant colon obstruction: A Honam Association for the Study of Intestinal Disease (HASID) multicenter study

Self-expandable metal stent (SEMS) placement is commonly used for palliation of left-sided malignant colorectal obstruction (MCO). However, right-sided MCO is usually treated surgically. Recent studies that compared palliative SEMS insertion and emergency surgery in right-sided MCOs have reported conflicting results. This study aimed to compare the effectiveness of palliative SEMS placement in left-sided MCOs and right-sided MCOs and to investigate the predictive factors for clinical success and risk factors for complications. Data from 469 patients who underwent palliative SEMS placement for MCO at 6 hospitals in the Honam province of South Korea between 2009 and 2018 were reviewed. Among them, 69 patients with right-sided MCO and 400 patients with left-sided MCO who underwent SEMS placement for palliative purposes were enrolled. Clinical success, overall survival, complications, and predictive factors for clinical success and risk factors for complications were included as the main outcome measures. The clinical success rates were 97.1% (65/67) in right-sided MCO patients and 88.2% (353/400) in left-sided MCO patients. Complications including stent migration, tumor ingrowth, outgrowth, perforation, bacteremia/fever, and bleeding occurred in 10.1% (7/69) of right-sided MCO patients and 19.9% (79/400) of left-sided MCO patients. The mean overall survival of right-sided MCO was 28.02 months and 18.23 months for left-sided MCO. In multivariate logistic regression analysis, T3 stage tumors and the use of uncovered stents were significant factors for the clinical success of SEMS. The use of covered stents and performance status score of 0 to 2 were independent significant risk factors for complications. Palliative SEMS placement in right-sided MCO showed better clinical success rates than left-sided MCO. The use of uncovered stents is recommended for higher clinical success rates and lower complication rates.

Predictors of clinical outcomes of self-expandable metal stent treatment for malignant colorectal obstruction: A Honam Association for the Study of Intestinal Disease (HASID) multicenter study

There has been increased use of self-expandable metal stents (SEMS) in treating malignant colorectal obstruction (MCO). The aim of this study was to investigate factors that are associated with the outcomes of SEMS placement for MCO.Clinical data from patients who underwent SEMS placement for MCO at 6 hospitals in Honam province of South Korea between 2009 and 2018 were reviewed retrospectively. Eight hundred two patients were identified and their data were analyzed. Technical success, clinical success, complications, and predictors of outcome were included as main outcome measures.Technical and clinical success rates were 98.8% (792/802) and 90.1% (723/802), respectively. Complications including stent migration, stent occlusion due to tumor ingrowth and outgrowth, perforation, bacteremia/fever, and bleeding occurred in 123 (15.3%) patients. In multivariate regression analyses, procedure time was significantly associated with the technical success of SEMS placement (P = .001). Longer length of obstruction, the use of covered stent, and longer procedure time were significant independent predictive factors for the clinical success of SEMS placement (odds ratio [OR] 0.974 (95% confidence interval [CI] 0.950-0.990); P = .043, OR 0.255 (95% CI 0.138-0.471); P < .001, and OR 0.957 (95% CI 0.931-0.984); P = .002, respectively). Stage IV colorectal cancer and the use of covered stent were significant independent predictive factors for the development of complications after SEMS placement (OR 2.428 (95% CI 1.407-4.188); P = .001 and OR 3.329 (95% CI 2.060-5.378); P < .001, respectively).Longer length of obstruction, the use of covered stent, and longer procedure time were associated with lower clinical success rates. Having stage IV colorectal cancer and the use of covered stents were associated with an increased risk of complications.

MRI findings of scapholunate instabilities in coronal images: a short communication

The plain radiographic findings of scapholunate instabilities are very well described in the literature. However, even though the same phenomena that are seen in plain radiographs are also seen in magnetic resonance (MR) images, there are very few reports in the literature regarding MRI findings in scapholunate instabilities. This short communication describes the findings seen in coronal MR images in advanced scapholunate instabilities.

Role of magnetization transfer imaging in bone tumors

RATIONALE AND OBJECTIVES

The authors evaluated the role of magnetization transfer imaging in differentiation of bone tumors, with special emphasis on cartilaginous tumors.

MATERIALS AND METHODS

Fifty-one patients with skeletal tumors or tumor-like lesions who had undergone magnetic resonance (MR) imaging were included. The tumors were divided into three groups according to their gross appearance and the origin of tissue: cyst, cartilaginous tumor, and noncartilaginous solid tumor. A gradient-recalled acquisition in the steady state sequence was used for MR imaging, and examinations were performed both with and without off-resonance magnetization transfer pulses. Magnetization transfer ratios were obtained as an indicator of magnetization transfer effect of the lesions and were compared. Then, the magnetization transfer ratios of all tumors in the cartilaginous tumor group were compared. The magnetization transfer ratios of benign and malignant solid tumors were also compared.

RESULTS

The mean magnetization transfer ratio for cartilaginous tumors was 0.31 +/- 0.08 (standard deviation), and that of cysts and noncartilaginous solid tumors was 0.07 +/- 0.03 and 0.40 +/- 0.14, respectively. Comparisons between the three groups showed statistically significant intergroup differences in magnetization transfer ratio (P < .05). In the cartilaginous tumor category, enchondroma and low-grade chondrosarcoma had a lower magnetization transfer effect than chondroblastoma and mesenchymal chondrosarcoma. The mean magnetization transfer ratios of benign (n = 28) and malignant (n = 18) tumors were 0.35 +/- 0.11 and 0.39 +/- 0.15, respectively; there was no statistically significant intergroup difference (P = .14).

CONCLUSION

Magnetization transfer imaging could be useful for categorizing bone tumors as cysts, cartilaginous tumors, or noncartilaginous solid tumors.

MR imaging of rabbit hip cartilage with a clinical imager and specifically designed surface coils

RATIONALE AND OBJECTIVES

The authors' purpose was to develop a magnetic resonance (MR) imaging technique for examining the hip joint of a rabbit with a clinical MR imager.

MATERIALS AND METHODS

Fourteen hips of 10 male New Zealand white rabbits were examined on a 1.5-T MR imager with a specially designed surface coil. Field of view was 3-8 cm, matrix was 256-512 x 192-256, section thickness was 0.9-2.0 mm, and spacing was 0.3-0.5 mm. The hips were sectioned and evaluated by means of light microscopy. Measurements of cartilage thickness from MR images were correlated with those from histologic specimens.

RESULTS

The resolution obtainable with a 1.5-T imager was adequate for imaging articular cartilage when a débrided rabbit hip specimen was placed in the center of a 3.5-cm single-loop coil. Rabbit hip cartilage had a trilaminar appearance on MR images. The coefficient of correlation between cartilage-thickness measurements was .81.

CONCLUSION

MR imaging of rabbit hip cartilage can be performed on 1.5-T clinical MR imaging unit. Limitations due to the field strength can be overcome with efficiently designed surface coils.

Ischiopubic insufficiency fractures: MRI appearances

OBJECTIVE

To evaluate the MRI appearances in insufficiency fractures.

DESIGN

A retrospective analysis of spin echo MR images with gadolinium-enhancement was undertaken with the emphasis on the signal change and the shape of the fracture gap and the adjacent bone marrow.

PATIENTS

Five elderly women who had ischiopubic insufficiency fractures (pubis, 4; ischium 1) underwent MRI to exclude the possibility of pathologic fractures.

RESULTS AND CONCLUSIONS

In no case was contrast enhancement noted at the fracture gap or the adjacent bone marrow, but a cleft-life, elongated bright signal area suggesting "fluid collection" was noted within the fracture gap. Absence of contrast enhancement and "fluid collection" at the fracture gap might suggest non-union of a fracture, which is additional information provided only by MRI.

Hemodialysis-related arthropathy. A prospective MR study with SE and GRE sequences

PURPOSE

A prospective examination of hemodialysis-related arthropathy by MR imaging with SE and GRE sequences was undertaken to verify whether the low signal intensity on T2-weighted SE images is caused by a paramagnetic susceptibility effect derived from amyloid or from hemosiderin.

MATERIAL AND METHODS

Twenty-seven joints (19 hip joints, 6 discovertebral joints of 5 lumbosacral spines and 1 cervical spine, 2 shoulder joints) in 14 patients undergoing long-term hemodialysis (duration 10-22 years, mean 17) were examined with SE T1-weighted, T2-weighted and GRE T2*-weighted sequences.

RESULTS

The signal intensity of the intraarticular and periarticular masses of the involved joints was basically isointense to the muscle in all 3 pulse sequences. No significantly low signal area was found on GRE T2*-weighted images.

CONCLUSION

The low signal areas in the hemodialysis-related arthropathy on SE T2-weighted images are not caused by a paramagnetic susceptibility effect, but probably by the hypocellular and fibrous nature of amyloid-containing tissues. Therefore the GRE sequence can be helpful for differentiating hemodialysis-related amyloid arthropathy from chronic hemarthrosis or juxta-articular brown tumor.

Intraosseous neurilemmoma of the fibula

We present a case of intraosseous neurilemmoma of the fibula in a 56-year-old woman. The case showed the typical radiographic appearance except for the presence of spotted calcifications that mimicked a cartilaginous tumor. Enhanced MR images revealed the heterogeneity of the tumor, which consisted of Antoni type A and B tissue.

Hyaline cartilage: in vivo and in vitro assessment with magnetization transfer imaging

PURPOSE

To elucidate the magnetization transfer (MT) effects of major components of hyaline cartilage.

MATERIALS AND METHODS

The authors evaluated the MT effect of type II collagen and chondroitin sulfate phantoms (concentrations of 0.6%, 1.2%, 2.4%, 4.8%, 9.6%, and 19.2%), mass-cultured rat osteosarcoma-derived cells, and normal articular cartilage of the knee.

RESULTS

The MT effect of collagen yielded a decrease in signal intensity of 10% (1.2% collagen) to 31% (19.2% collagen); the decrease varied linearly with collagen concentration. Chondroitin sulfate did not have a statistically significant MT effect. Cell pellets showed a decrease in signal intensity of 22%-26%, which was greater than that of 4.8% collagen. Normal articular cartilage of the knees showed a decrease in signal intensity of 38%-48%.

CONCLUSION

The major role of collagen in MT contrast of hyaline cartilage was confirmed. In addition, a higher cellular contribution to the MT effect was also demonstrated.

[Effect of collagen on magnetization transfer contrast assessed in cultured cartilage]

We investigated the effect of collagen on magnetization transfer contrast (MTC) in cultured cartilage. In our culture system, only collagen synthesis was increased by the addition of vitamin C, while proteoglycan synthesis and the number of chondrocytes were unaffected. The MTC effect was assessed by using an off-resonance RF pulse (0.3 KHz off-resonance, sinc wave of 18 msec, maximum amplitude 4.61 x 10(-4)T) on a GRASS sequence. The cartilage cultured with vitamin C showed a higher MTC effect than that cultured without vitamin C. The major role of collagen on MTC was confirmed in living cartilage tissue.

MR findings indicative of hemosiderin in giant-cell tumor of bone: frequency, cause, and diagnostic significance

OBJECTIVE

We studied the frequency, cause, and diagnostic significance of MR findings indicative of large amounts of hemosiderin in giant-cell tumor of bone.

MATERIALS AND METHODS

The clinical, MR, and histologic findings in 16 patients with giant-cell tumors of bone were reviewed. Eight tumors occurred in uncommon locations or in patients who were not in the usual age range; the other eight were more typical. Areas of decreased MR signal intensity considered to be caused by hemosiderin were identified. The number and distribution of RBCs within the tumor were studied histologically, and the presence of hemosiderin was determined on histologic sections made with iron stains.

RESULTS

In 10 cases in which MR images showed areas of low signal intensity, large amounts of hemosiderin were noted histologically. The low-signal-intensity areas were nodular, zonal, whorled, or diffuse and occupied at least one fifth of the tumor volume. On histologic examination, many erythrocytes were in direct contact with the tumor cells, and the hemosiderin was seen in both mononuclear and multinuclear tumor cells.

CONCLUSION

Hemosiderin is commonly seen on MR images of giant-cell tumors of bone (63%) and is probably related to the extravasated erythrocytes in the tumor and the phagocytic function of the tumor cells. This MR finding supports the diagnosis, even in giant-cell tumors in uncommon locations or in patients who are not in the typical age range.

Epidural dumbbell-shaped chordoma mimicking a neurinoma

The authors present a case of cervical chordoma which manifested in a 5-year-old boy as a dumbbell-shaped epidural tumor without bone destruction. Both CT and MRI demonstrated tumor features suggesting this diagnosis, which was confirmed by histology.

[Radiological and anatomical investigation of calcific tendinitis of the gluteus maximus tendon]

The radiological findings in four cases of gluteus maximus tendinitis were retrospectively analyzed. All the patients underwent radiographic, CT and MRI examinations. Amorphous or round calcifications were detected on lateral radiographs in three cases, and on CT in all cases. A small cortical erosion was observed in three cases on both radiographs and CT. MRI showed a thickened gluteus maximus tendon, but no other specific features. In the supine position, which is common in routine CT and MRI studies, the calcific deposits appeared to be distributed along the vastus lateralis muscle tendon. To correlate these radiographic observations with the topographic anatomy of the tendon's insertion, we investigated 14 thighs of seven cadavers, and clarified that the tendon's insertion was the main component of the lateral femoral intermuscular septum. Consequently we performed MRI on a volunteer in a prone position who was asked to maintain contraction of the gluteus maximus and quadratus femoris muscles. The images obtained showed clearly that the gluteus maximus tendon was directed dorsally. In conclusion, radiography and CT are the modalities of choice for diagnosis of this entity. Additionally, radiologists should be aware that the gluteus maximus tendons are directed laterally as a main part of the lateral femoral intermuscular septum on routine CT and MRI.

[Clinical application of digital TV tomosynthesis to disorders of the wrist and their post-operative evaluation]

The clinical utility of digital TV tomosynthesis was assessed in 13 patients with chronic disorders of the wrist and the first carpometacarpal joints, and a post-operative evaluation was carried out. The disorders included nonunion of the scaphoid in five patients, Kienböck's disease in four, subluxation of the distal radioulnar joint in two, and osteoarthrosis of the first carpometacarpal joint in two. The total time needed to obtain two sets of tomographs of a wrist by digital TV tomosynthesis was about 10 minutes, or approximately one third of the time required with conventional methods. The total radiation exposure in obtaining all tomographs of one direction with digital TV tomosynthesis was less than that in obtaining only one tomograph with conventional methods. Digital TV tomosynthetic images were judged superior to conventional tomographs by four orthopedic surgeons and four radiologists, because tomographic blur was reduced in part by a spatial frequency filter processing. Clinically, digital TV tomosynthesis was very helpful in evaluating nonunion of the scaphoid and Kienböck's disease, especially in their post-operative conditions with metallic fixative devices. Digital TV tomosynthesis was found to be a fast, feasible and inexpensive method with low radiation exposure for evaluating disorders of the wrist.

MR appearance of periosteal chondrosarcoma of the foot

OBJECTIVE

To assess the role of MRI in evaluating periosteal chondrosarcoma in the foot, an anatomically complicated location.

MATERIALS AND METHODS

Three cases of surgically and histologically confirmed periosteal chondrosarcomas occurring in the foot (58-year-old woman, 57-year-old woman, and 63-year-old man) were retrospectively reviewed with an emphasis on MR findings.

RESULTS

Magnetic resonance successfully delineated the hypovascular nature and lobulating pattern of the lesion suggesting the cartilaginous component, the periosteal location with sparing bone marrow, and the extent of involvement of adjacent structures. These findings were either not seen or less clearly seen on CT in the former two cases.

CONCLUSION

In cases of periosteal chondrosarcomas in the foot MRI can play a significant role both in the characterization of the lesion and in planning surgical therapy.

Assessment of bone density in the distal radius with computer assisted X-ray densitometry (CXD)

A modified and improved radiographic absorptiometry of the distal radius which enables on-site analysis, called computer assisted X-ray densitometry (CXD), was evaluated from the viewpoint of quality assessment. Its precision and the correlation with dual energy X-ray absorptiometry (DXA) was evaluated in 12 volunteers (mean age 44.7 years). The profile of CXD-measured radial bone mineral density (RBMD) from 142 subjects (75 premenopausal and 67 postmenopausal women, mean ages 44.9 and 50.6 years, respectively) were compared with previous data by other methodologies of bone mineral analysis. The intra-assay coefficient of variation (CV) was 0.617%, the inter-assay CV was 2.064%, and the inter-observer CV was 0.673%. The correlation between CXD-measured RBMD and DXA-measured RBMD was of statistical significance (r2 = 0.733, P < 0.01). The correlation of CXD-measured RBMD with age, height or weight corresponded well with previous reports. CXD-measured RBMD and DXA-measured vertebral bone mineral density (VBMD) also had a significant positive correlation, but their correlation was not so close (r2 = 0.149, P < 0.01). The discriminative ability of osteoporosis by CXD was of acceptable level (odd's ratio = 5.72, P < 0.05), when assessed by comparison with bone dystrophy score (BDS) on the plain vertebral radiogram. Although some problems remain in technical standardization, CXD could be an easy, inexpensive, and widely applicable alternative of non-weight bearing cancellous bone densitometry.

Accentuated temporal line on the frontal skull radiograph: a sign of hyperparathyroidism

PURPOSE

To determine the importance of a temporal line (the marginal line for the attachment of the temporal muscle to the skull) that is accentuated on frontal skull radiographs of hyperparathyroid patients owing to subligamentous bone resorption under the temporal muscle.

MATERIALS AND METHODS

Radiographs from skeletal surveys of 134 surgically treated patients with primary (n = 102) or secondary (n = 32) hyperparathyroidism (HPT) and frontal skull radiographs of 63 age-matched control patients were reviewed.

RESULTS

An accentuated temporal line was the most frequent finding (29.4% of cases) in primary HPT, followed by subperiosteal bone resorption in the hand (8.6%), salt-and-pepper appearance of the skull (3.5%), and rugger-jersey spine (1.1%). In secondary HPT, an accentuated temporal line became less obvious as subperiosteal bone resorption advanced. This finding was not seen in the control group.

CONCLUSION

An accentuated temporal line is another radiographic indication of bone resorption in HPT.

Assessment of reducibility of ileocolic intussusception in children: usefulness of color Doppler sonography

PURPOSE

To assess the diagnostic usefulness of ultrasonography (US) in intussusception in children and determine whether color Doppler sonography (CDS) can indicate bowel viability and help in prediction of reducibility.

MATERIALS AND METHODS

US was used to examine 176 children in whom the presence of intussusception was clinically suspected. CDS was performed in 64 patients with 65 cases of intussusception proved with US.

RESULTS

The positive US findings were confirmed with air enema; the negative findings, with air enema in 46 patients and clinical follow-up in 66 patients (100% specificity and sensitivity). CDS indicated blood flow in 62 of 65 cases of intussusception; pneumatic reduction was achieved in 58 (94%) of these 62 cases. Four patients (6%) underwent manual reduction of viable bowel; three patients (5%) who had no color Doppler signal underwent segmental resection. The difference in reduction rates based on blood flow was statistically significant (P = .0008).

CONCLUSION

US is sensitive and specific in the diagnosis of intussusception, and CDS is a promising predictor of bowel viability.

Diagnosis of acute appendicitis in pregnant women: value of sonography

OBJECTIVE

The diagnosis of acute appendicitis in pregnant women often is difficult to make on the basis of clinical findings, and radiologic examination is limited because of the potentially hazardous effects of radiation. This study was done to assess the value of sonography in the diagnosis of acute appendicitis in pregnant women.

SUBJECTS AND METHODS

We obtained sonograms in 45 pregnant women with clinically suspected acute appendicitis. Our sonographic technique included graded-compression scanning. The left lateral decubitus position was used in the third trimester of gestation. The sonographic criterion for the diagnosis of acute appendicitis was visualization of an incompressible appendix with a maximal diameter greater than 7 mm. We correlated the sonographic findings with the surgical findings in 22 cases and with the results of clinical follow-up in 23 cases.

RESULTS

Sonography could not be used to make the diagnosis in three (7%) of 45 patients because the size of the gravid uterus prevented use of the graded-compression technique. These three patients were in the third trimester of pregnancy (greater than 35 weeks' gestation). Sonographic findings were used as a basis for diagnosis in 42 cases. Acute appendicitis was diagnosed on the basis of sonograms in 16 patients, and in all but one of these patients, acute appendicitis was confirmed by surgical and pathologic findings. In the 42 cases in which the imaging findings indicated the diagnosis, the overall sensitivity of sonography was 100%, the specificity was 96%, and the accuracy was 98%.

CONCLUSION

Our experience suggests that graded-compression sonography is a valuable procedure for detecting acute appendicitis in pregnant women despite technical difficulty in performing it during the third trimester of pregnancy.