Catherine Maldjian

MRI APPEARANCE OF PLACENTA PERCRETA AND PLACENTA ACCRETA

The purpose of this paper is to describe the magnetic resonance imaging (MR) features of placenta accreta and percreta. We retrospectively reviewed MRI findings in four cases of placenta accreta/percreta to determine features which assist in identifying the presence and extent of placental implantation abnormality. All patients had ultrasound (US) examinations. Pathologic correlation was available in all cases. There were two cases of placenta percreta and two cases of placenta accreta. All cases were treated by hysterectomy. In the two cases of placenta percreta, the placenta demonstrated transmural extension through the uterus (percreta) on MRI. In the two cases of placenta accreta, the location of thinning in the uterine wall correlated with the location of placental invagination into the myometrium at pathology. US correlation was available in all four cases. Gray scale US did not demonstrate placental invasion in any of the four cases of placenta accreta/percreta, however, in two of three cases in which color Doppler was performed, there was flow at the uterine margin suspicious for implantation abnormality. In conclusion, MRI is useful for identifying the presence and extent of placenta accreta/percreta.

Cervical carotid artery dissection: current review of diagnosis and treatment.

Carotid artery dissection is a cause of stroke, especially in young and middle-aged patients. A dissection occurs when there is an intimal tear or rupture of the vasa vasorum, leading to an intramural hematoma, which is thought to result from trauma or can occur spontaneously, and is likely multifactorial, involving environmental and intrinsic factors. The clinical diagnosis of carotid artery dissection can be challenging, with common presentations including pain, partial Horner syndrome, cranial nerve palsies, or cerebral ischemia. With the use of noninvasive imaging, including magnetic resonance and computed tomography angiography, the diagnosis of carotid dissection has increased in frequency. Treatment options include thrombolysis, antiplatelet or anticoagulation therapy, endovascular or surgical interventions. The choice of appropriate therapy remains controversial as most carotid dissections heal on their own and there are no randomized trials to compare treatment options.

DIAGNOSTIC AND THERAPEUTIC FEATURES OF FACET AND SACROILIAC JOINT INJECTION: Anatomy, Pathophysiology, and Technique

A diagnosis of exclusion facet syndrome is considered one of the many genuine causes of low back pain. Using careful patient selection, percutaneous facet joint block is a useful diagnostic and therapeutic procedure in the management of lumbar facet syndrome. Sacroiliac joint syndrome appears to be a more tangible entity diagnostically and more amenable to injection. This article addresses the anatomy, pathophysiology, and salient radiographic features of the apophyseal joint, and describes the procedures and techniques for facet as well as sacroiliac joint injection.

MRI appearance of the pelvis in the post cesarean-section patient.

Fever in the post-cesarean section patient may indicate the presence of a potentially life-threatening complication, including abscess, ovarian vein thrombosis, and uterine dehiscence. Imaging findings are often utilized to ascertain the presence or absence of such complications. Familiarity with the normal findings in the post-operative period is essential in making this determination. The purpose of this investigation is to describe the MRI appearance of the post-cesarean section pelvis. Over a 67-month period, 50 patients with persistent low-grade fevers following c-section were referred for MR imaging. Imaging was performed 3-10 days post-operatively. Axial T1-weighted and T2-weighted images were acquired in addition to sagittal T2-weighted images. Coronal images were obtained in some cases. Clinical correlation was obtained through the patients charts, confirming discharge of the patients in stable condition. The uterine incision site usually demonstrated findings consistent with subacute hematoma. The anterior uterine myometrium demonstrated enlargement relative to the posterior uterine wall. Bladder flap hematomas were seen in 64% of cases. Three cases (6%) demonstrated parametrial edema and none of these patients demonstrated ovarian vein thrombosis. Two cases of pelvic hematoma were noted. The normal post-c-section incision site may demonstrate increased or decreased signal intensity on T2-weighted images and intact endometrial and serosal layers mitigate against the diagnosis of incisional dehiscence. Bladder flap hematomas occurred in slightly more than half the cases. Parametrial edema and pelvic hematoma can be seen as post-surgical changes.

MR appearance of uterine dehiscence in the post-cesarean section patient.

PURPOSE CT has been shown to be unreliable for detecting uterine dehiscence in the postoperative period after cesarean section (c-section). The purpose of this investigation is to describe the MR appearance of uterine dehiscence in this setting and identify features that distinguish complete from partial dehiscence. METHOD Over an 82 month period, all charts and MR reports of patients that underwent MRI of the pelvis after c-section were reviewed for uterine dehiscence. Altogether, 55 patients were imaged. Positive cases for dehiscence were retrospectively reviewed by two radiologists. Imaging criteria for complete dehiscence consisted of transmural disruption. Criteria for partial dehiscence consisted of disruption of the endometrial and/or serosal layer, without transmural extension. RESULTS On MRI, five patients demonstrated abnormalities suggestive of incisional dehiscence. Based on these imaging criteria, two of these showed complete dehiscence that was proven at surgery and three showed findings of partial dehiscence. The optimal imaging plane was perpendicular to the incision. CONCLUSION MR features may be utilized to identify total uterine dehiscence and may be more effective than CT.

MRI appearance of clear cell hidradenoma.

Abstract We present the first reported MR imaging findings of a histologically proven clear cell hidradenoma. A fluid level was noted on all pulse sequences in this lesion, which demonstrated a prominent hemorrhagic component on sectioning. The presence of an enhancing nodule was also noted, differentiating this lesion from a post-traumatic hematoma. Fluid levels in a well-defined subcutaneous soft tissue mass should suggest the possibility of a hidradenoma.

Hyperphosphatasemia: report of three cases

We report the radiographic findings in three cases of hyperphosphatasemia. Often classified as a congenital bone dysplasia, the skeletal manifestations of this disorder are diagnostic. These features simulate Pagets disease both radiographically and with respect to salient biochemical markers. Typically, presentation is at early childhood with skull deformity, refusal to weight bear, and bowing of the extremities. Notable radiographic features include bowing of the long bones, thickening of the cortex, osteopenia, coarsened trabecular pattern, expansion of the medullary cavity, and thickening of the intramembranous portion of the calvarium. Histologic features include absence of lamellar bone and haversian systems, with thick osteoid seams and increased number of osteoclasts. An autosomal recessive pattern of inheritance has been suggested, although autosomal dominant varieties have been postulated.

Volume fast spin-echo imaging of the cervical spine

RATIONALE AND OBJECTIVES The authors prospectively evaluated a T2-weighted, three-dimensional (3D) volume, fast spin-echo (SE) pulse sequence in assessment of the cervical spine and compared it with standard imaging protocol. MATERIALS AND METHODS Eighteen patients with neck pain underwent magnetic resonance (MR) imaging at 1.5 T with two-dimensional (2D) fast SE and axial 3D gradient-echo (GRE) protocols and with an additional sagittal T2-weighted volume fast SE protocol. The spinal cord and canal, neural foramina, and intervertebral disks were assessed by two neuroradiologists, and the results were compared with reports from the standard protocol. The quality of the partition (direct sagittal) and reconstructed images were evaluated. RESULTS No differences existed in the assessment of spinal cord disease or disk herniation with 2D fast SE and volume fast SE imaging. Some mild variation occurred in assessment of the neural foramina. Partition images demonstrated a high level of resolution and contrast, while reconstructed images had consistently lower quality. However, this did not impede detection and grading of disk or spinal abnormalities, which were adequately shown on volume fast SE sagittal images. Neural foramina were well demonstrated on axial reconstructions from volume fast SE imaging. CONCLUSION Volume fast SE imaging provides information about the spinal cord, canal, disks, and neural foramina that is comparable to the information provided by routine imaging. Its thinner sections and multiplanar reconstruction capability are advantages over 2D imaging. Its greater tissue contrast with better visualization of the cervical cord, greater signal-to-noise ratio, and less susceptibility artifact are advantages over 3D GRE imaging.

Volume (Three-dimensional) Fast Spin-Echo Imaging of the Lumbar Spine '

RATIONALE AND OBJECTIVES The purpose of this study was to prospectively evaluate a proton-density-weighted, three-dimensional (3D) volume fast spin-echo (SE) pulse sequence in the assessment of the lumbar spine for suspected spondylosis. MATERIALS AND METHODS Twenty-eight patients referred for low back or lower extremity pain were imaged with both a two-dimensional (2D) protocol and a proton-density-weighted 3D volume fast SE imaging. The spinal canal, conus medullaris, intervertebral disks, neural foramina, bone marrow, and spinal alignment shown with the 3D volume fast SE pulse sequence were independently assessed by two neuroradiologists. These findings were compared with those of the routine 2D studies. RESULTS Interpretation of disk protrusions and stenoses of the neural foramina were concordant between both protocols. No instance of cord abnormality was detected with either protocol. CONCLUSION A 3D volume fast SE proton-density-weighted pulse sequence may provide information comparable to that of routine 2D imaging. Advantages of volume imaging include thinner sections, the capability of reconstruction into any plane, and the potential to decrease imaging time.

Comparison of Insall-Salvati Ratios in Children With an Acute Anterior Cruciate Ligament Tear and a Matched Control Population

OBJECTIVE An anterior cruciate ligament (ACL) injury is an increasingly recognized cause of knee pain in young patients and in athletes in particular and can be detected non-invasively with MRI. Anecdotal information suggests that patella alta may be more common in the setting of this injury, but no study has documented this phenomenon. This study sought to test whether an ACL tear is associated with an increased Insall-Salvati ratio suggestive of patella alta. MATERIALS AND METHODS Measurements of patellar height, patellar tendon length, and the Insall-Salvati ratio obtained from MRI of the knee were compared for 34 children with an arthroscopically proven ACL tear (mean age ± SD, 12.4 ± 1.4 years) and 36 control subjects with normal knee examinations (12.8 ± 2.1 years); these measurements were performed independently by two observers. RESULTS Patellar tendon length (47.6 ± 6.6 mm vs 40.4 ± 5.7 mm) and patellar position calculated as the Insall-Salvati ratio (1.16 ± 0.16 vs 0.99 ± 0.14) were significantly greater in the knees with an ACL injury than in those without an internal injury, respectively, on MRI (p < 0.001). Patella length was not significantly different between the two groups (patients vs control subjects, 41.1 ± 4.2 mm vs 40.6 ± 2.7 mm, respectively; p = 0.523). There was good to excellent interobserver and intraobserver correlation for all measurements. CONCLUSION There is a significant association between an ACL tear and increased patellar tendon length with a greater Insall-Salvati ratio. The mechanism for this finding is unclear, but this association provides support to suggest relative patella alta may be a risk factor for ACL injuries in pediatric patients.