Fractures of proximal portion of fifth metatarsal bone: anatomic and imaging evidence of a pathogenesis of avulsion of the plantar aponeurosis and the short peroneal muscle tendon

PURPOSE

To evaluate the normal anatomy of the structures supporting the proximal portion of the fifth metatarsal bone and investigate the pathogenesis of fractures in this region.

MATERIALS AND METHODS

In two cadaveric feet, the region of the lateral component of the plantar aponeurosis (PAL), short peroneal muscle (SPM) tendon, and third peroneal muscle (TPM) tendon was dissected. These two foot specimens and four nondissected foot specimens were studied at magnetic resonance (MR) imaging. Two of the six specimens were studied at computed tomography (CT). Sectioning the nondissected foot specimens enabled anatomic correlation. In two additional specimens, simulation of the presumed mechanism of fifth metatarsal bone fracture was attempted. The radiographic, CT, and MR images obtained in 13 patients with fractures of the proximal portion of the fifth metatarsal bone were evaluated.

RESULTS

Anatomic, CT, and MR imaging studies revealed broad insertion of the PAL into the plantar aspect of the proximal portion of the fifth metatarsal bone in all specimens. The SPM tendon was consistently attached more distally and to the lateral side of the tuberosity, blending with the PAL fibers. The TPM tendon was inconsistently identified inserting anteriorly to the SPM tendon. No fracture was created in the specimens subjected to attempted injury. Frequent attachment of the PAL and the SPM tendon to the avulsed fragment was confirmed in clinical cases.

CONCLUSION

The pathogenesis of fractures of the proximal portion of the fifth metatarsal bone appears to be related to avulsion injury of PAL and SPM tendon fibers.

Skeletal muscle disease: patterns of MRI appearances

Although the presumptive diagnosis of skeletal muscle disease (myopathy) may be made on the basis of clinical-radiological correlation in many cases, muscle biopsy remains the cornerstone of diagnosis. Myopathy is suspected when patients complain that the involved muscle is painful and tender, when they experience difficulty performing tasks that require muscle strength or when they develop various systemic manifestations. Because the cause of musculoskeletal pain may be difficult to determine clinically in many cases, MRI is increasingly utilised to assess the anatomical location, extent and severity of several pathological conditions affecting muscle. Infectious, inflammatory, traumatic, neurological, neoplastic and iatrogenic conditions can cause abnormal signal intensity on MRI. Although diverse, some diseases have similar MRI appearances, whereas others present distinct patterns of signal intensity abnormality. In general, alterations in muscle signal intensity fall into one of three cardinal patterns: muscle oedema, fatty infiltration and mass lesion. Because some of the muscular disorders may require medical or surgical treatment, correct diagnosis is essential. In this regard, MRI features, when correlated with clinical and laboratory findings as well as findings from other methods such as electromyography, may facilitate correct diagnosis. This article will review and illustrate the spectrum of MRI appearances in several primary and systemic disorders affecting muscle, both common and uncommon. The aim of this article is to provide radiologists and clinicians with a collective, yet succinct and useful, guide to a wide array of myopathies.

Reciprocal contribution of pentraxin 3 and C-reactive protein to obesity and metabolic syndrome

Pentraxin 3 (PTX3) is an acute-phase protein that shares structural homology with C-reactive protein (CRP). PTX3 is produced in macrophages, endothelial cells, and adipocytes in response to inflammatory stimuli, whereas hepatocytes are the main source of CRP. Because obesity and metabolic syndrome (MetS) are considered chronic inflammatory states, PTX3 might be involved in the pathogenesis of obesity and MetS as well as CRP. Levels of CRP correlated positively with body weight, BMI, waist circumference (WC), fasting plasma glucose and interleukin (IL)-6, and negatively with high-density lipoprotein cholesterol and adiponectin in healthy males. In contrast, PTX3 correlated positively with adiponectin, and negatively with body weight, BMI, WC, and triglyceride. Plasma CRP significantly increased, whereas plasma PTX3 significantly decreased with increasing BMI. Plasma CRP and PTX3 levels were significantly higher and lower, respectively, in individuals who had more than one MetS component compared with those who had none. In conclusion, PTX3 and CRP antagonistically participate in the development of obesity or MetS.

MRI of ossification of ligamentum flavum

Magnetic resonance imaging of 28 patients with radiological and/or histopathologically proved ossification of the ligamentum flavum (OLF) was reviewed. The locations of OLF were cervical (n = 4), thoracic (n = 22), and lumbar (n = 2). On T1- and T2-weighted images, OLF demonstrated low signal intensity. Areas of high or intermediate signal intensity within the OLF on T1-weighted images were observed in three cases and were interpreted to be due to fat infiltration. In six cases, high intensity areas in the spinal cord caused by compressing OLF were demonstrated on T2-weighted images. Gadolinium-diethylenetriamine pentaacetic acid, which was used in four cases, showed cord enhancement at the level of compression by OLF in three cases.

Plantar fasciitis and fascial rupture: MR imaging findings in 26 patients supplemented with anatomic data in cadavers

Understanding of the normal anatomy of the plantar aponeurosis (PA) and familiarity with pathologic conditions are required for an accurate evaluation of the patient with subcalcaneal heel pain. In this study, we evaluated the diagnostic capabilities of magnetic resonance (MR) imaging in the assessment of the PA with close anatomic correlation. Herein, we describe the MR imaging features of plantar fasciitis and fascial rupture in 26 patients. High-spatial-resolution MR imaging was performed in four cadaveric feet, and a prescribed imaging plane was used for depiction of the peroneal component of the PA. MR imaging delineated the anatomy of the PA and perifascial soft tissues. The peroneal component was best visualized in prescribed sagittal oblique images. Perifascial edema was the most common finding of plantar fasciitis, and it was remarkable in those cases with acute fascial rupture. MR imaging reliably delineated the anatomy of the PA and may allow precise localization and definition of the extent of involvement in disease processes.

Calcium pyrophosphate dihydrate crystal deposition in and around the atlantoaxial joint: association with type 2 odontoid fractures in nine patients

PURPOSE

To investigate the histopathologic anatomy of calcium pyrophosphate dihydrate (CPPD) crystal deposition in and around the atlantoaxial joint and the association between CPPD crystal deposition and subchondral cysts, erosions, and fracture involving the odontoid process of the axis.

MATERIALS AND METHODS

One adult cadaver demonstrating calcification in the retro-odontoid area at computed tomography (CT) was selected for further radiography, CT, and magnetic resonance (MR) imaging at the C1-2 level. Anatomic sectioning and histologic evaluations were performed in the specimen. For clinical study, radiographs (n = 5), CT scans (n = 8), and MR images (n = 6) in nine patients (mean age, 74.4 years) with odontoid process fractures and CPPD crystal deposits in and around the atlantoaxial joint were reviewed.

RESULTS

In the cadaveric specimen, radiography and CT demonstrated calcifications in the transverse ligament; histologic evaluation confirmed that these calcifications were CPPD crystal deposits. In all nine patients, radiography (n = 5) and CT (n = 8) also showed calcification in areas adjacent to the odontoid process, which included the transverse ligament. T1- and T2-weighted MR imaging showed a retro-odontoid mass of low signal intensity that compressed the cervical cord in six patients. CT, MR imaging, or both demonstrated subchondral cysts, osseous erosions, or a type 2 odontoid fracture in all patients.

CONCLUSION

CPPD crystal deposition disease involving the C1-C2 articulation can be a clinically important entity that may place affected patients at increased risk of pathologic fracture of the odontoid process.

Stress fractures of the lateral metatarsal bones in metatarsus adductus foot deformity: a previously unrecognized association

OBJECTIVE

To document a distinctive pattern of stress fractures in the lateral metatarsal bones of patients with metatarsus adductus foot deformity.

DESIGN AND PATIENTS

Conventional radiographs and available medical records were reviewed in 11 patients (6 women, 5 men; ages 25-61 years) with stress fractures of the lateral (fourth or fifth) metatarsal bones and metatarsus adductus. Evaluation included the number and location of fracture(s), forefoot adduction angle, and qualitative assessment of bone mineral density. Conditions that might predispose patients to metatarsal fractures, including direct trauma, osteoporosis, and neuropathic osteoarthropathy were also recorded.

RESULTS

A total of 22 stress fractures were demonstrated, 17 of which involved the lateral metatarsals. A solitary fracture was present in six patients, while multiple fractures were evident in five patients. The sites of involvement were the fifth metatarsal (n=10), fourth metatarsal (n=7), third metatarsal (n=3), second metatarsal (n=1), and first metatarsal (n=1) bones. The locations of the stress fractures were in the proximal one-third of the metatarsal bones in 19 instances (86%) and in the middle one-third in three instances (14%). Forefoot adduction angle measured between 21 degrees and 37 degrees (normal range 8 degrees -14 degrees).

CONCLUSION

Patients with metatarsus adductus may be at increased risk for stress fractures involving the lateral metatarsal bones, likely owing to the presence of altered biomechanics that place greater loads across the lateral aspect of the foot.

Magnetic resonance imaging of retained surgical sponges. Case report

The magnetic resonance imaging (MRI) features of sponges retained postsurgically in three patients are described. MRI depicted these as well-defined round masses, which were of low signal intensity on T1-weighted images and very high signal intensity on T2-weighted images. We scrutinized these masses on T2-weighted images. MRI revealed the low-signal-intensity structures to have wavy, striped, and/or spotted appearances, which raised the suspicion that they might be retained surgical sponges within mass lesions.

Spontaneous spinal subarachnoid hemorrhage associated with subdural hematoma at different spinal levels

We describe the clinical features and MR-imaging findings of spontaneous spinal subarachnoid hemorrhage located in the lumbar spine associated with subdural hematoma at a higher, thoracic level in a 66-year-old man without neurological deficit. The sequential MR-imaging changes of hemorrhage at various stages in its evolution are portrayed. The possible pathogenetic mechanism for these very unusual, combined hemorrhages in both spinal compartments is discussed.

Magnetic resonance discography in cadavers: tears of the annulus fibrosus

The purpose of this study was to investigate the diagnostic capabilities of magnetic resonance discography in the detection of tears of the annulus fibrosus, and to compare the findings with those derived from conventional magnetic resonance imaging. Twenty-four intervertebral discs from cadavers were examined with magnetic resonance imaging and magnetic resonance discography, and anatomic correlation was done. Forty-six annular tears were documented on anatomic inspection of the specimens. Magnetic resonance discography allowed significantly better observation of radial than transverse annular tears, and identification of radial tears was significantly better than that of concentric tears. With magnetic resonance discography, detectability of concentric tears was not significantly better than that of the transverse tears. No significant differences in the detection of different types of annular tears were appreciated on the magnetic resonance images obtained before discography. Magnetic resonance discography allowed direct diagnosis of radial, transverse, and concentric tears in 100%, 57%, and 21% of specimens, respectively. With magnetic resonance imaging, the diagnosis of radial, transverse, and concentric tears was possible in 67%, 71%, and 21% of specimens, respectively. Magnetic resonance discography does well in the evaluation of the clinically important radial tears of the annulus fibrosus, although not uniformly well in the identification of other types of annular tears.

Sonography and venography of the lower extremities for diagnosing deep vein thrombosis in symptomatic patients

The purpose of this study was to investigate the efficacy of sonography and the frequency of indeterminate sonographic examinations in the evaluation of patients with suspected lower extremity deep vein thrombosis (DVT). We prospectively evaluated 136 symptomatic patients (157 extremities) with suspected DVT using sonography and contrast-enhanced venography (n=106 patients, 115 extremities). Using venography as the reference standard for diagnosing DVT, the sensitivity and specificity of sonography was 92.8% and 98%, respectively, yielding an accuracy of 96.8%. The frequency of indeterminate examinations for calf DVT was 32.4%. One (0.7%) fatal pulmonary embolus occurred in our patients. The pulmonary embolism (PE) rate was 1.6% after lower extremity sonography with negative results. Sonography is highly accurate in detecting lower extremity DVT in symptomatic patients. Because of the high frequency of indeterminate studies in the calf and the associated possible risk of pulmonary emboli, we urge radiologists exercise additional caution when evaluating symptomatic patients with clinically suspected lower extremity DVT.

Mesenteric plexiform neurofibroma associated with Recklinghausen's disease

We present a rare case of plexiform neurofibroma involving the ileal mesentery of a 10-year-old boy with Recklinghausen's disease. MRI showed multiple ring-like structures in the masses on T2-weighted and contrast enhanced T1-weighted images. Probably these findings reflect enlarged peripheral nerves with myxoid degeneration. MRI is useful for the diagnosis of mesenteric plexiform neurofibroma because of this characteristic appearance.

CT manifestations of lipomas of the small intestine and colon

Seven cases of lipoma of the intestine demonstrated by computed tomography (CT) are reported. There were three men and four women who ranged in age from 47 to 78 years. The lipomas were in the small intestine in four patients, and in the colon in three. CT documented the characteristic low attenuation (fat density) of these masses in all patients. It is concluded that intestinal lipomas are important indications for CT evaluations.

Cartilaginous endplates of the spine: MRI with anatomic correlation in cadavers

PURPOSE

The purpose of this work was to describe the MR appearance of cartilaginous endplates (CEPs) with close anatomic correlation in cadavers derived from elderly subjects.

METHOD

High-resolution MRI was performed on five cadaveric lumbar spines, and a total of 48 CEPs were studied with T1-weighted spin echo, T2-weighted fast spin echo, and fat-suppressed 3D spoiled GRASS gradient echo (SPGR) MR images. All specimens underwent anatomic sectioning, and gross anatomic findings were correlated with those of MRI.

RESULTS

Conventional MR images allowed gross morphologic evaluation of the integrity of the CEPs and demonstrated cartilaginous nodes. In all specimens, fat-suppressed 3D-SPGR images invariably improved visualization of the fine anatomic structures at the diskovertebral junction (p < 0.01). Various morphologic abnormalities of the CEPs demonstrated on MR images, including thinning, irregularity, erosions, cartilaginous defects, and Schmorl nodes, were confirmed on anatomic inspection.

CONCLUSION

Results in our study indicate that MRI may delineate the normal anatomy of CEPs and demonstrate morphologic changes occurring at the diskovertebral junction. Dedicated high-resolution technique and fat-suppressed 3D-SPGR images may significantly improve the diagnostic capabilities of MRI of this particular anatomic region.

CT and MRI manifestations of intraabdominal panniculitis

We report a case of intraabdominal panniculitis. Computed tomography (CT) showed diffuse increased attenuation in the omentum, mesentery, and retroperitoneal region. As the disease progressed, the entire mesentery and retroperitoneal regions were involved. On magnetic resonance imaging (MRI), the lesion demonstrated an intermediate signal intensity on T1-weighted images and a slightly high signal intensity on T2-weighted images. Though the radiologic findings are not specific, this condition should be considered in the appropriate clinical context.

Myofibroblastic inflammatory tumor of the lung: CT findings with pathologic correlation

The objective of this study was to describe the computed tomographic (CT) features of myofibroblastic inflammatory tumor of the lung with histopathologic correlation. The medical records and imaging studies of eight patients with pathologically proven myofibroblastic inflammatory tumor of the lung were reviewed. On radiographs and CT images, a poorly circumscribed mass or nodule was evident in five patients (six lesions), and a well-circumscribed lesion was evident in three patients (three lesions). Seven lesions were peripheral and two were centrally located. At CT, five lesions were of heterogeneous attenuation and four homogeneous. Increased perilesional parenchymal abnormalities, which were caused by peribronchial inflammatory infiltrates, were observed in three cases. The predominant histopathologic feature was organizing pneumonia type in three cases, lymphoplasmacytic type in three cases, and both organizing pneumonia and lymphoplasmacytic type in two cases. Variable degree of fibrous histiocytoma type was observed in all cases. The imaging characteristics of myofibroblastic inflammatory tumor of the lung are variable and nonspecific. The authors conclude that most cases appear as solitary, peripheral lesions with a predilection for the lower lobes. Associated findings may include perilesional inflammatory changes. Because myofibroblastic inflammatory tumor cannot be reliably differentiated from other pulmonary lesions based solely on the imaging appearance diagnostic biopsy is mandatory. Interpretation of the imaging findings combined with the histopathologic features of disease may help make correct diagnosis.

Lipoma of the falciform ligament: US, CT, and MRI appearances

A case of lipoma of the falciform ligament was demonstrated using computed tomography (CT), ultrasonography (US), and magnetic resonance imaging (MRI). US demonstrated a heterogeneous solid mass anteriorly in the upper portion of the abdomen. CT and MRI revealed a solitary, fatty mass with a small amount of soft tissue in it.

Neurofibromatosis type 1 involving the liver: ultrasound and CT manifestations

We present a rare case of neurofibromatosis type 1 (NF-1) involving the liver in a 15-year-old girl. Abdominal ultrasonography revealed infiltrative hypoechoic masses around the porta hepatitis and intrahepatic portal branches. CT also revealed extensive low-attenuation masses in the hepatic hilum and retroperitoneum. The tumor spread into the liver along the portal vein. It should be borne in mind that the liver may be involved by neurofibromas in patients with NF-1.

Absence of the left lobe of the liver: US and CT appearance

We report five cases of absence of the left liver lobe diagnosed by ultrasonography (US) and/or computed tomography (CT). There were four men and one woman, with an average age of 62.8 years. The right lobe was normal in four patients and enlarged in one. A tongue-like hypertrophy of the caudate lobe was present in two patients. The gallbladder was located at the left portion of the liver. Elevation of the antrum of the stomach was also seen.

Intraspinal gas associated with intestinal necrosis detected by CT

We report the case of a 63-year-old woman with necrosis of the small intestine and intraspinal collections of gas, which were detected using computed tomography (CT). Abdominal CT revealed extensive collections of gas in the portal and mesenteric veins and within the intestinal walls. Gas radiolucencies were also noted in the epidural spaces of her spine. This gas was considered to have migrated from the pelvic venous system into the internal venous plexus of the spine. Intestinal necrosis should be included in the differential diagnosis of intraspinal gas collections during CT.

Optimal timing for delineation of hepatocellular carcinoma in dynamic CT

OBJECTIVE

The aim of our study was to ascertain the optimal timing and scanning method for detecting hepatocellular carcinoma (HCC) as a high density mass during the early phase of dynamic hepatic CT and to confirm its clinical effectiveness.

MATERIALS AND METHODS

We studied retrospectively 39 patients with clinically diagnosed HCC who underwent dynamic hepatic CT.

RESULTS

All nine lesions that were scanned within 60 s after initiating injections were detected as high density masses. However, 15 of 21 lesions (71%) that were scanned > 70 s after initiating injections could not be detected as high density masses. Using helical scanning, which permitted scanning the entire liver within 60 s after initiating injections, 27 of 31 lesions (87%) were detected as high density masses.

CONCLUSION

We concluded that most HCCs can be detected as high density masses during the early phase of dynamic CT using helical scanning.

Intrahepatic portal-hepatic venous shunts demonstrated by US, CT, and MR imaging

PURPOSE

Radiological findings were investigated in 6 cases of intrahepatic portal-hepatic venous shunt (IPHVS) without chronic liver disease.

MATERIAL AND METHODS

Six patients with IPHVS were examined using US, CT and MR imaging. US was performed in all patients and color Doppler imaging in 5 patients. CT was performed after i.v. bolus injection of contrast medium in 4 patients. MR imaging and MR angiography were performed in one patient.

RESULTS

The shunt was present in the right lobe in 4 patients and in the left lobe in 2 patients. The shunts consisted of focally dilated or tubular vessels (1 aneurysmal) in 4 patients, and multiple small vessels in 2 patients. US revealed anechoic structures with various configurations at the shunt. Color Doppler imaging could detect blood flow in various directions in the shunt vessels in 5 patients. CT and MR images showed these abnormal vascular structures in the liver. MR angiography was also useful for evaluating the relationship between the portal and the hepatic veins.

CONCLUSION

Color Doppler imaging was the best modality for evaluation of IPHVS.