Qualitative Assessment and Reporting Quality of Intracranial Vessel Wall MR Imaging Studies: A Systematic Review

BACKGROUND

Over the last quarter-century, the number of publications using vessel wall MR imaging has increased. Although many narrative reviews offer insight into technique and diagnostic applications, a systematic review of publication trends and reporting quality has not been conducted to identify unmet needs and future directions.

PURPOSE

We aimed to identify which intracranial vasculopathies need more data and to highlight areas of strengths and weaknesses in reporting.

DATA SOURCES

PubMed, EMBASE, and MEDLINE databases were searched up to September 2018 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines.

DATA ANALYSIS

Two independent reviewers screened and extracted data from 128 articles. The Strengthening the Reporting of Observational Studies in Epidemiology guidelines were used to assess the reporting quality of analytic observational studies.

DATA SYNTHESIS

There has been an exponentially increasing trend in the number of vessel wall MR imaging publications during the past 24 years (P < .0001). Intracranial atherosclerosis is the most commonly studied intracranial vasculopathy (49%), followed by dissections (13%), aneurysms (8%), and vasculitis (5%). Analytic observational study designs composed 48% of the studies. Transcontinental collaborations showed nonsignificantly higher reporting quality compared with work originating from single continents (P = .20).

LIMITATIONS

A limitation is the heterogeneity in study designs.

CONCLUSIONS

Investigations on the diagnostic utility of vessel wall MR imaging in less commonly studied intracranial vasculopathies such as dissections, aneurysms, and vasculitis are warranted. More consistent adherence to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines should improve transparency and maximize effective synthesis for clinical translation. Diverse collaborative teams are encouraged to advance the understanding of intracranial vasculopathies using vessel wall MR imaging.

Reversible Dilation of the Superior Ophthalmic Vein in Intubated Patients

BACKGROUND AND PURPOSE

Superior ophthalmic vein enlargement has typically been associated with increased intracranial or orbital pressure. This study evaluates the incidence of superior ophthalmic vein enlargement in intubated patients without pre-existing intracranial or intraorbital pathologies.

MATERIALS AND METHODS

Two cohorts (patients with trauma and epilepsy patients undergoing stereotactic intracranial lead placement) who underwent CT while intubated and shortly following extubation and a cohort of 30 outpatients with a history of headache and normal head CT findings (healthy controls) were included. The superior ophthalmic vein diameter was measured on all scans.

RESULTS

Seventy patients intubated for trauma and 45 patients with intraoperative CT were included (n = 115). While intubated, 66% of the total sample had at least unilateral superior ophthalmic vein dilation of >2.5 mm and 48% had bilateral dilation. Fifty-seven percent of patients with trauma and 84% of intraoperative patients with dilated superior ophthalmic veins showed reversal of mean superior ophthalmic vein dilation to <2.5 mm on postextubation CT. The mean superior ophthalmic vein diameter decreased an average of 1.2 mm following extubation. Changes in superior ophthalmic vein diameter between intubated and extubated states were statistically significant (P < .001). Differences between the control group and the extubated subjects were not statistically significant (P = .21).

CONCLUSIONS

Bilateral dilation of the superior ophthalmic vein is common in intubated patients and usually reverses following extubation. In the appropriate clinical setting, this knowledge will prevent misinterpretation of prominent superior ophthalmic veins as automatically indicative of an underlying pathology.

Dynamic Contrast-Enhanced MRI-Derived Intracellular Water Lifetime (τ i ): A Prognostic Marker for Patients with Head and Neck Squamous Cell Carcinomas

BACKGROUND AND PURPOSE

Shutter-speed model analysis of dynamic contrast-enhanced MR imaging allows estimation of mean intracellular water molecule lifetime (a measure of cellular energy metabolism) and volume transfer constant (a measure of hemodynamics). The purpose of this study was to investigate the prognostic utility of pretreatment mean intracellular water molecule lifetime and volume transfer constant in predicting overall survival in patients with squamous cell carcinomas of the head and neck and to stratify p16-positive patients based upon survival outcome.

MATERIALS AND METHODS

A cohort of 60 patients underwent dynamic contrast-enhanced MR imaging before treatment. Median, mean intracellular water molecule lifetime and volume transfer constant values from metastatic nodes were computed from each patient. Kaplan-Meier analyses were performed to associate mean intracellular water molecule lifetime and volume transfer constant and their combination with overall survival for the first 2 years, 5 years, and beyond (median duration, >7 years).

RESULTS

By the last date of observation, 18 patients had died, and median follow-up for surviving patients (n = 42) was 8.32 years. Patients with high mean intracellular water molecule lifetime (4 deaths) had significantly (P = .01) prolonged overall survival by 5 years compared with those with low mean intracellular water molecule lifetime (13 deaths). Similarly, patients with high mean intracellular water molecule lifetime (4 deaths) had significantly (P = .006) longer overall survival at long-term duration than those with low mean intracellular water molecule lifetime (14 deaths). However, volume transfer constant was a significant predictor for only the 5-year follow-up period. There was some evidence (P < .10) to suggest that mean intracellular water molecule lifetime and volume transfer constant were associated with overall survival for the first 2 years. Patients with high mean intracellular water molecule lifetime and high volume transfer constant were associated with significantly (P < .01) longer overall survival compared with other groups for all follow-up periods. In addition, p16-positive patients with high mean intracellular water molecule lifetime and high volume transfer constant demonstrated a trend toward the longest overall survival.

CONCLUSIONS

A combined analysis of mean intracellular water molecule lifetime and volume transfer constant provided the best model to predict overall survival in patients with squamous cell carcinomas of the head and neck.

Incidental radiologic findings in the 22q11.2 deletion syndrome

BACKGROUND AND PURPOSE

The 22q11.2 deletion syndrome is a common genetic microdeletion syndrome that results in cognitive delays and an increased risk of several psychiatric disorders, particularly schizophrenia. The current study investigates the prevalence of incidental neuroradiologic findings within this population and their relationships with psychiatric conditions.

MATERIALS AND METHODS

Brain MR imaging from 58 individuals with 22q11.2 deletion syndrome was reviewed by board-certified radiologists by using standard clinical procedures. Intracranial incidental findings were classified into 8 categories and compared with a large typically developing cohort.

RESULTS

The rate of incidental findings was significantly higher (P < .0001) in 22q11.2 deletion syndrome compared with typically developing individuals, driven by a high prevalence of cavum septum pellucidum (19.0%) and white matter abnormalities (10.3%). Both of these findings were associated with psychosis in 22q11.2 deletion syndrome.

CONCLUSIONS

Cavum septum pellucidum and white matter hyperintensities are significantly more prevalent in patients with the 22q11.2 deletion syndrome and may represent biomarkers for psychosis.

MR imaging evolution of endoscopic cranial defect reconstructions using nasoseptal flaps and their distinction from neoplasm

BACKGROUND AND PURPOSE

Endoscopic endonasal approach is the procedure of choice for the resection of ventral skull base neoplasms, with defect closure requiring multilayer reconstruction. This study evaluates the temporal MR imaging evolution of nasoseptal flaps and free grafts used in endoscopic skull base reconstruction.

MATERIALS AND METHODS

Sixty-nine follow-up brain MRIs of 22 patients who had endoscopic skull base reconstruction using 26 nasoseptal flaps combined with 8 collagen-matrix dural grafts, 10 fascia lata grafts, and 10 intracranial fat grafts were retrospectively reviewed. Temporal changes in signal intensity, enhancement, thickness, and the configuration of reconstructive layers were evaluated. Tissue with signal intensity or enhancement different from that of normal evolving reconstructive layers at the surgical bed was evaluated, and its association with clinically confirmed tumor was assessed with the Fisher exact test.

RESULTS

All normal reconstructive layers were retracted to cranial defects and showed maturation of imaging features within 2-6 months. The immediate postoperative T2-isointensity to brain and enhancement of nasoseptal flaps persisted, but the flap thickness was reduced by 20%-30% (average thickness, 4.5 ± 1.3 mm); additionally, the C shape and vascular pedicle of the nasoseptal flaps became indistinct, but the flap location remained unchanged. The initial appearance of the nonenhancing fascia lata with variable T2 signal intensity became enhancing with increasing T2-hypointensity and a graft-thickness reduction of ≥50% (average thickness, 3.5 ± 1.6 mm). All fat grafts showed progressive resorption. In 6 patients, abnormal tissue represented residual or recurrent tumor (P = .0001).

CONCLUSIONS

Maturation and stability of multilayer endoscopic skull base reconstructions on MR imaging occurs within 2-6 months postoperatively. Understanding of the normal imaging evolution of endoscopic skull base reconstructions is essential to distinguish them from neoplasms.

Prediction of disease-free survival in patients with squamous cell carcinomas of the head and neck using dynamic contrast-enhanced MR imaging

BACKGROUND AND PURPOSE

Patients with HNSCC have a poor prognosis and development of imaging biomarkers that predict long-term outcome might aid in planning optimal treatment strategies. Therefore, the purpose of the present study was to predict disease-free survival in patients with HNSCC by using pretreatment K(trans) measured from dynamic contrast-enhanced MR imaging.

MATERIALS AND METHODS

Sixty-six patients with HNSCC were recruited from January 2005 to October 2008. Three patients were excluded because they underwent upfront neck dissection, and 6 patients were excluded due to suboptimal MR imaging data or being lost to follow-up. Disease-free survival was measured in the remaining 57 patients from the end date of chemoradiation therapy. In patients who died, the end point was the date of death, while in surviving patients the date of last clinical follow-up was used as the end point. Pretreatment K(trans) and nodal volume were computed from the largest metastatic node, and median pretreatment K(trans) and volume were used to divide patients into 2 groups (at or above the threshold value [group I] and below the threshold value [group II]. Disease-free survival was analyzed by the Kaplan-Meier method, and the results were compared by using a logrank test with K(trans) and nodal volume as predictors. A P value <.05 was considered significant.

RESULTS

Thirteen of 57 patients had died of HNSCC by the last follow-up period (March 31, 2009). Patients with higher pretreatment K(trans) values had prolonged disease-free survival compared with patients with lower K(trans) values (P=.029). However, there was no significant difference in disease-free survival when nodal volume was used as a predictor (P=.599).

CONCLUSIONS

Pretreatment K(trans) may be a useful prognostic marker in HNSCC.

Respiratory epithelial adenomatoid hamartoma of the bilateral olfactory recesses: a neoplastic mimic?

REAH is a rare benign lesion of the sinonasal tract. The nasal cavity, particularly the posterior nasal septum, is the most common site of involvement. It usually occurs unilaterally and can be cured with conservative surgical resection. We present an unusual case of adenomatoid hamartoma involving bilateral olfactory recesses and discuss the importance of distinguishing this from other neoplastic processes that may lead to overly aggressive treatment.

Prediction of response to chemoradiation therapy in squamous cell carcinomas of the head and neck using dynamic contrast-enhanced MR imaging

BACKGROUND AND PURPOSE

Tumor microenvironment, including blood flow and permeability, may provide crucial information regarding response to chemoradiation therapy. Thus, the objective of this study was to investigate the efficacy of pretreatment DCE-MR imaging for prediction of response to chemoradiation therapy in HNSCC.

MATERIALS AND METHODS

DCE-MR imaging studies were performed on 33 patients with newly diagnosed HNSCC before neoadjuvant chemoradiation therapy by using a 1.5T (n = 24) or a 3T (n = 9) magnet. The data were analyzed by using SSM for estimation of K(trans), v(e), and tau(i). Response to treatment was determined on completion of chemoradiation as CR, with no evidence of disease (clinically or pathologically), or PR, with pathologically proved residual tumor.

RESULTS

The average pretreatment K(trans) value of the CR group (0.64 +/- 0.11 minutes(-1), n = 24) was significantly higher (P = .001) than that of the PR (0.21 +/- 0.05 minutes(-1), n = 9) group. No significant difference was found in other pharmacokinetic model parameters: v(e) and tau(i), between the 2 groups. Although the PR group had larger metastatic nodal volume than the CR group, it was not significantly different (P = .276).

CONCLUSIONS

These results indicate that pretreatment DCE-MR imaging can be potentially used for prediction of response to chemoradiation therapy of HNSCC.

Inflammatory pseudotumor of the trigeminal nerve: a neoplastic mimic you do not want to miss

Inflammatory pseudotumor is a rare non-neoplastic mass that may clinically and radiologically mimic a spectrum of benign and malignant neoplasms. It is uncommon in the head and neck and particularly rare at the skull base. We present a case of pseudotumor originating from the trigeminal nerve in a patient who presented with headache and facial numbness. A high index of suspicion is necessary to diagnose this benign but locally aggressive entity.

Effect of BRAFV600E on response to sorafenib in advanced thyroid cancer patients

6002

Background: We are conducting an open-label phase II study of sorafenib in patients with metastatic, iodine-refractory thyroid carcinoma. Methods: 55 Patients were administered sorafenib 400 mg orally BID. Responses were monitored by PET and CT. Primary endpoints were response rate (RR) and progression free survival (PFS) by RECIST criteria. BRAF and RAS mutation status is determined by DNA sequencing. Outcome data is evaluated using the Kaplan-Meier method and log-rank test. Biologic activity in tissue obtained during treatment at response and progression is being explored using immunohistochemistry (IHC) to pERK, pAKT and Ki-67 among others, in pretreatment blocks from virtually all patients, and a subset of 14 patients in whom on-treatment tissue is available. Results: We have completed accrual of the 55 patients planned for enrollment; median time on study is 34 weeks and 25 pts (45%) are male. Histological subtypes include papillary (PTC): 25 pts (47%); follicular/Hürthle Cell (FTC): 19 pts (36%); medullary: 4 pts (8%), and poorly differentiated/anaplastic: 5 pts (9%). 52/55 patients are evaluable for response at this time. Median PFS was 84 wks. Genotyping of BRAF is complete in 16 patients. For patients with PTC/FTC, the PFS for those with BRAFwt was 54 wks compared to 84+ wks for patients with BRAFV600E (p = 0.028). On-treatment tissue at progression demonstrates heterogeneity, with p-ERK and p-AKT suppressed in some areas, but highly expressed in others. Data at 6 months post accrual of the last patient will be presented along with patient thyroglobulin levels, PET and CT scans. IHC and additional genotyping will also be presented. Conclusions: Sorafenib has activity in patients with advanced thyroid cancer with an overall PFS of 84 wks. While most patients with PTC or FTC achieve durable responses, patients whose tumors harbor BRAFV600E have significantly longer PFS than those that are BRAFwt.

[Table: see text]

Retained surgical sponges after craniotomies: imaging appearances and complications

Imaging within 24 to 48 hours after most neurosurgical procedures is a routine practice. Nonresorbable surgical sponges have radiopaque filaments readily visible on CT scans and plain film radiographs. However, the proton-poor barium sulfate responsible for this radio-opacity is generally not detectable on MR imaging in the immediate post-operative period. Findings on MR imaging become more evident with elapsing time and when a foreign-body reaction to the sponge manifests as a mass lesion, which can mimic residual or recurrent intracranial tumor or abscess. Although preventive measures by our surgical colleagues to ensure accurate and correct sponge counts before and after wound closure is paramount, even the most fastidious efforts may rarely result in an inadvertently retained surgical sponge. The role of the radiologist is to recognize the imaging findings of this entity and its potential complications so that appropriate and prompt management can be initiated.

The role of MR imaging in detecting nodal disease in thyroidectomy patients with rising thyroglobulin levels

BACKGROUND AND PURPOSE

One of the dilemmas facing clinicians treating patients with thyroid cancer is the evaluation of postthyroidectomy patients with rising serum thyroglobulin levels and indeterminate or normal findings on neck sonography. In this study, we examine the role of MR imaging in this subgroup of patients.

MATERIALS AND METHODS

We retrospectively reviewed MR images of patients with thyroid cancer with abnormal lymph nodes in the retropharyngeal and parapharyngeal spaces and determined the size and signal-intensity characteristics of these nodes. We reviewed patient charts for the following history: 1) thyroidectomy, 2) rising thyroglobulin levels, 3) iodine-131 radiation therapy, 4) neck dissection, and 5) pathology on neck sonography and chest CT. We reviewed pathology findings to determine if thyroid cancer metastases were present in these lymph nodes.

RESULTS

Eight patients had abnormal retropharyngeal space nodes, and 1 patient had a parapharyngeal space mass. Lymph nodes ranged from 7 to 25 mm. On MR imaging, 1 patient had a cystic node, 2 had complex nodes, and 6 had solid nodes. Eight patients had rising serum thyroglobulin levels and a history of thyroidectomy, radioiodine therapy, and neck dissection. Two of these patients had no pathologic nodes on sonography and normal findings on chest CT. Six patients had tissue sampling of their skull base node, and metastatic thyroid cancer was present in 5.

CONCLUSIONS

MR imaging of the neck should be considered in thyroidectomy patients with rising serum thyroglobulin levels and a history of radioiodine therapy and neck dissection. Radiologists should carefully examine the retropharyngeal and parapharyngeal spaces in these patients because nodal metastases may occur there more commonly than realized.

Imaging characteristics of recurrent pleomorphic adenoma of the parotid gland

BACKGROUND AND PURPOSE

Pleomorphic adenoma is the most common parotid neoplasm. It has a relatively high rate of recurrence after surgery. Imaging features of recurrent parotid pleomorphic adenoma have been infrequently reported in the radiology literature. In the present study, we reviewed our institutional experience with imaging of recurrent parotid pleomorphic adenomas.

MATERIALS AND METHODS

Retrospective imaging and chart review of 24 patients (9 men, 15 women; age, 29-63 years) with recurrent pleomorphic adenoma of the parotid were performed. Images were reviewed as to the margins, site, multiplicity, signal intensity, and enhancement pattern of the recurrent lesions by 2 neuroradiologists.

RESULTS

We found a high incidence of multiple lesions in the operative bed, most of which were extremely bright on T2-weighted images; some of the lesions demonstrated a cystic appearance with peripheral enhancement. We also noted tiny lesions in the subcutaneous fat and in regions distant from the immediate operative bed.

CONCLUSION

Although recurrent disease is usually clinically apparent, sometimes prior surgical history is lacking or recurrence may be detected on routine surveillance imaging after initial surgery. The presence of solitary or multiple subcutaneous T2 hyperintense lesions in the operative bed, subcutaneous fat, and/or spaces adjacent to the parotid in patients with prior parotidectomy for pleomorphic adenoma is consistent with the diagnosis of neoplastic recurrence. The radiologist should maintain a high index of suspicion for recurrent pleomorphic adenoma with this characteristic imaging appearance.

Idiopathic hypereosinophilic syndrome with skull base involvement

Idiopathic hypereosinophilic syndrome (HES) is a heterogeneous disorder characterized by prolonged eosinophilia without an identifiable cause, ultimately resulting in organ dysfunction. Three major types of neurologic involvement have been well defined in HES; however, to our knowledge, inflammatory pseudotumor (IPT) in association with HES has not been reported. We present a case of IPT of the skull base in a patient with HES that suggests that HES may result in an exaggerated immunologic or inflammatory response leading to the formation of IPT.

Simultaneous bilateral internal carotid and vertebral artery dissection following chiropractic manipulation: case report and review of the literature

Single-vessel cervical arterial dissections typically occur in young adults and are a common cause of cerebral ischemia and stroke. Although the pathogenesis of multivessel dissection is unclear, it is thought to be a consequence of underlying collagen vascular disease. We present a 34-year-old previously healthy man who developed bilateral internal carotid and vertebral artery dissection following chiropractic manipulation.

Mycotic aneurysm and cerebral infarction resulting from fungal sinusitis: imaging and pathologic correlation

SUMMARY

A 73-year-old man was admitted with invasive aspergillus of the sphenoid sinus. Endoscopic debridement of the sphenoid sinus was complicated by rupture of a mycotic cavernous carotid artery aneurysm with severe epistaxis. The aneurysm was closed emergently by endovascular coil placement. Subsequently, the mycotic aneurysm extended intradurally and caused fatal subarachnoid hemorrhage. The radiologic-pathologic data illustrate the mechanism of fungal mycotic aneurysm formation and growth. This case emphasizes the need for rapid diagnosis of potential fungal involvement of the central nervous system and suggests the necessity for aggressive treatment once fungal cerebrovascular involvement is identified.

MR imaging for predicting neoplastic invasion of the cervical esophagus

BACKGROUND AND PURPOSE

Esophageal invasion (EI) by head and neck neoplasm has important prognostic and surgical management implications. Our purpose was to determine the accuracy of MR imaging for predicting neoplastic cervical esophageal invasion.

METHODS

MR scans of the neck obtained from 22 patients with periesophageal masses were retrospectively reviewed independently and by consensus by two experienced head and neck radiologists who were unaware of surgical findings. The patients were selected from clinical, radiologic, or pathologic reports suggesting EI. The following imaging criteria for EI were evaluated: effacement of periesophageal fat planes, circumferential mass, paraesophageal lymph nodes, luminal size, wall thickening, increased T2 wall signal, and wall enhancement. There were eight patients with EI and 14 patients without EI, as confirmed by surgical findings or pathologic examination.

RESULTS

The consensus criteria with the best sensitivities were any wall thickening (100%), effaced fat plane (100%), and any T2 wall signal abnormality (100%). The criteria with the best specificities were circumferential mass greater than 270 (100%) or 180 degrees (93%) and focal T2 wall signal abnormality (86%). The overall kappa value for the two readers for all criteria was 0.57 (moderate agreement).

CONCLUSION

A circumferential mass or focal T2 signal abnormality on the esophageal wall suggests the presence of EI. An intact fat plane, absence of wall thickening, and no T2 wall signal abnormalities imply that the esophagus is not invaded.

Preoperative imaging to predict orbital invasion by tumor

BACKGROUND

Our purpose was to examine the accuracy of preoperative imaging in assessing tumor invasion of the orbit and nasolacrimal system.

METHODS

Nineteen preoperative CT and 17 preoperative MR images from patients at risk for orbital invasion were retrospectively reviewed. Invasion was corroborated by pathologic and intraoperative assessment.

RESULTS

Tumor adjacent to the periorbita was the most sensitive predictor of orbital invasion (90%) for both CT and MRI. Extraocular muscle involvement on MRI (100%) and orbital fat obliteration (80% MRI, 86% CT) had the highest positive predictive values of the criteria evaluated. Extraocular muscle displacement and enhancement were less accurate (<65%) predictors. No one criterion was >79% accurate in predicting orbital invasion. Six or more positive criteria predicted invasion with 67% sensitivity and 80% specificity (accuracy, 72%). CT was more accurate than MRI in seven of nine criteria. Invasion of the nasolacrimal system was predicted accurately (89%).

CONCLUSIONS

Although preoperative imaging can aid in surgical planning, it should not replace intraoperative assessment in ambiguous cases of orbital invasion.

Posttransplantation lymphoproliferative disorder of the head and neck: imaging features in seven adults

PURPOSE

To determine the cross-sectional imaging findings of posttransplantation lymphoproliferative disorder (PTLD) of the head and neck.

MATERIALS AND METHODS

Computed tomographic (CT) scans (n = 6) and magnetic resonance (MR) images (n = 2) in seven patients with histopathologically proved PTLD of the Waldeyer (lymphoid) ring or cervical lymph nodes were retrospectively reviewed for abnormalities.

RESULTS

The interval between transplantation and PTLD onset was 3.5-108 months (mean, 30 months). All patients had imaging abnormalities involving the Waldeyer ring, and focal 2.0-4. 5-cm masses were present in six patients (unilateral oropharyngeal tonsil in two, bilateral oropharyngeal tonsils in one, nasopharyngeal adenoids in three, unilateral pharyngeal tonsil and ipsilateral nasopharynx in one). In three patients, the mass was centrally low attenuating at CT or isointense to fluid at MR imaging, with enhancing solid peripheral lymphoid tissue. Three patients also had nodal findings: one with a 7-cm low-attenuating nodal mass in the right neck and two with numerous bilateral lymph nodes (mostly normal sized) in the anterior and posterior cervical lymph chains. One patient also had a small mass in the upper mediastinum.

CONCLUSION

In the setting of organ transplantation, findings of masses in the Waldeyer ring or an excessive number of cervical nodes should increase the index of suspicion of PTLD.

Prevalence of unsuspected acoustic neuroma found by magnetic resonance imaging

OBJECTIVES

Acoustic neuromas (ANs) comprise 6% of intracranial tumors. Population and autopsy studies have widely divergent estimates of AN incidence. With widespread use of MRI, asymptomatic ANs will be identified, which should improve estimates of the prevalence of this tumor.

METHODS

The reports of all brain MRI scans during a 5-year period were retrospectively searched for the diagnosis of AN. MRIs obtained because of a suspicion of AN were discarded, leaving only the unsuspected ANs.

RESULTS

A total of 24, 246 MRI studies were performed during this time period. Seventeen patients had unsuspected ANs. Eight tumors were smaller than 1 cm, 6 were between 1 and 2 cm, and 3 were 2 cm or larger. For all MRI scans, we found 7.0 unsuspected ANs per 10,000 brain MRI studies (0. 07%).

CONCLUSION

The true prevalence of AN is likely greater than the 10 per million per year previously reported. This implies that there may be a larger number of asymptomatic ANs than previously suspected.

The lateral osteotomy in rhinoplasty: clinical and radiographic rationale for osteotome selection

A preferred osteotome for endonasal osteotomy would facilitate reliable, complete osteotomies with minimal soft-tissue trauma. In this report, a radiographic evaluation of the bony lateral nasal wall thickness along the track of a high-low-high osteotomy was undertaken to guide the determination of appropriate osteotome size. Bone window axial computed tomographic scans were evaluated in 56 patients with a mean age of 48 years (range, 19 to 86 years). The average thickness along the site of lateral osteotomy was determined to be 2.47 mm (standard deviation, 0.47) in male patients and 2.29 mm (standard deviation, 0.40) in female patients. On the basis of these data, clinical evaluation of prototype 3- and 2.5-mm low-profile guarded osteotomes was undertaken in comparison with a "standard" 4-mm low-profile guarded osteotome to assess both their reliability and the degree of intranasal trauma, as reflected by intranasal mucosal tears. Although 2- and 3-mm unguarded osteotomes are time-tested, they may be reliable only in the hands of the most experienced surgeons. Therefore, a low-profile guard was included in the osteotome design to allow the surgeon to engage the bone securely and minimize the risk of slippage. Forty patients underwent rhinoplasty, for a total of 80 lateral osteotomies; the mean age of the patients was 38 (range, 16 to 75). In all cases, lateral osteotomies were accomplished with one pass. The 4-mm osteotome causes intranasal mucosal tears in 95 percent of osteotomies, the 3-mm osteotome in 34 percent, and the 2.5-mm in 4 percent. Early postoperative edema and ecchymosis were comparable among the groups. One patient, who underwent osteotomies with a 4-mm osteotome, had excessive postoperative narrowing, possibly due to his wearing of eyeglasses earlier than directed. This report suggests that proper selection of osteotome and attention to proper surgical technique results in a reliable, minimally traumatic lateral osteotomy through the endonasal approach. The 2.5-mm osteotome was reliable and the least traumatic to soft tissue of the osteotomes evaluated.

Extensive intracranial xanthoma associated with type II hyperlipidemia

Xanthomas are associated with a spectrum of medical conditions, most commonly disorders of lipid storage and lipid metabolism. They occur primarily in the subcutaneous tissues, especially along the Achilles tendon and the extensor tendons of the hands. Intracranial xanthomas are extremely rare. We present a case of an extensive xanthoma of the temporal bone in a patient with hyperlipidemia.

Nuchal fibroma: a clinicopathological review

Nuchal fibroma, or collagenosis nuchae, is a benign soft tissue tumor that arises from the posterior cervical subcutaneous tissue, with a predilection for the interscapular and paraspinal regions. Because of its benign clinical course and its close histopathologic similarity to other benign head and neck lesions, this lesion may be misdiagnosed and underreported. The purpose of this paper is to review the histopathologic and radiologic findings unique to nuchal fibroma, and compare and contrast it to the other soft tissue neoplasms within the clinical differential diagnosis. These include several benign (elastofibroma, lipoma, fibrolipoma, nodular fasciitis) and rare malignant entities (fibrosarcoma, liposarcoma, fibromatosis).

Sound- and pressure-induced vertigo associated with dehiscence of the roof of the superior semicircular canal

In many types of peripheral vertigo, imaging is not part of the initial evaluation. We present a patient with sound- and pressure-induced vertigo associated with bony dehiscence of the roof of the superior semicircular canal. The diagnosis of this new entity can only be made by high-resolution coronal CT imaging of the temporal bones. In patients with this symptom complex, CT should be performed early in the diagnostic workup.

Superficial siderosis of the CNS associated with multiple cavernous malformations

Superficial siderosis of the CNS due to chronic, recurrent subarachnoid hemorrhage is an uncommon and potentially debilitating disorder. The classic clinical manifestation is progressive bilateral sensorineural hearing loss (SNHL), although ataxia and pyramidal signs also are observed frequently. Cavernous malformations rarely present with subarachnoid hemorrhage. We describe an unusual case of a young patient who presented with progressive, bilateral SNHL who was found to have superficial CNS siderosis associated with multiple cavernous malformations.

Imaging features of posterior fossa neoplasms in children and adults

Masses in the posterior fossa may be divided into extra-axial and intra-axial lesions. Because of its multiplanar capabilities, improved soft-tissue resolution and contrast, and the absence of scanning artifacts related to the osseous skull base, which are frequently present on CT, MRI is the imaging modality of choice in evaluating lesions arising in the posterior fossa. It is the best means of critically localizing lesions and determining the extent of disease. Analysis of the signal characteristics of a lesion on multiple different imaging sequences (T1-weighted, T2-weighted, and enhanced images) may provide information about the tissue constituents within a mass/neoplasm, such as the presence of cellularity, necrosis, and hemorrhage. MRI is also useful in guiding localization for brain tumor biopsies and assists in planning radiation therapy. However, CT also plays an important role. CT is frequently the first imaging study performed in patients with posterior fossa masses who often present with nausea, vomitting, ataxia, and other signs of increased intracranial pressure. It is a quick, available, and relatively inexpensive study to assess neurological emergencies including hydrocephalus, hemorrhage, and herniation syndromes. In addition, it frequently provides complimentary information, such as the presence of calcification or bony remodeling (osteosclerosis or osteolysis), which MRI is less sensitive in detecting.

Gadolinium-enhanced fat-suppressed T1-weighted imaging of the head and neck: comparison of gradient and conventional SE sequences

PURPOSE

The purpose of this study was to compare contrast-enhanced GRE and conventional SE (CSE) fat-suppressed T1-weighted techniques in the evaluation of head and neck lesions. A hybrid, opposed phase, frequency-selective, fat-suppressed fast multiplanar spoiled GRE (FMPSPGR) sequence was compared with a fat-suppressed CSE sequence.

METHOD

Thirty-two patients with head and neck pathology were evaluated with both fat-suppressed CSE and FMPSPGR sequences. Regions of interest obtained by two viewers in consensus were used to establish contrast-to-noise (CNR) and signal-to-noise ratios for both sequences. Three neuroradiologists also independently reviewed the images for quality of fat suppression, lesion conspicuity, and potential pitfalls.

RESULTS

The CNR of the FMPSPGR sequence was superior to that of the fat-suppressed CSE sequence. Subjectively, all three reviewers rated the FMPSPGR sequence as having fat suppression equal to or better than that in the CSE sequence in 94% of cases. Imaging times for the FMPSPGR sequence were 60-75% faster than those for the CSE sequence.

CONCLUSION

Enhanced imaging of the head and neck region using an opposed phase, fat-suppressed GRE sequence results in improved fat suppression compared with the CSE technique, with substantial savings in imaging time.

Neoplastic fixation to the prevertebral compartment by squamous cell carcinoma of the head and neck

OBJECTIVE

The purpose of this study was to determine the accuracy of MR imaging in determining fixation of squamous cell carcinomas to the prevertebral space.

MATERIALS AND METHODS

MR images of 15 patients with large pharyngeal carcinoma (n = 13) or laryngeal carcinomas with pharyngeal extension (n = 2) were retrospectively reviewed independently by two head and neck radiologists who were unaware of the surgical findings. MR images were evaluated for four criteria in the prevertebral longus muscle complex: muscle concavity, irregular tumor-muscle interface, T2 hyperintensity, and enhancement. All patients underwent panendoscopy where fixation or mobility of the tumor relative to the prevertebral fascia was assessed by manual manipulation. Tumors in six patients were fixed to the prevertebral space and inoperable. In nine patients whose tumors were not fixed, open neck explorations were performed and tumors were resected in seven patients. MR findings were compared with panendoscopy in all patients and with intraoperative assessment in nine patients.

RESULTS

Eleven of 15 patients had at least two of the MR imaging criteria present. None of the MR findings were both sensitive and specific for tumor fixation. Although muscle concavity and enhancement each had a sensitivity of 88%, both criteria suffered from low specificity (14% and 29%, respectively). An irregular tumor-muscle interface and muscle T2 hyperintensity were criteria that suffered from both low sensitivity and specificity. Accuracy of the imaging criteria independently ranged from 53% to 60%.

CONCLUSION

Although abnormal muscle contour, T2 hyperintensity, and enhancement are frequently present in neck carcinomas that are fixed to the prevertebral space, these findings may also be present in patients in whom the tumor is mobile and resectable. MR imaging may not be able to differentiate between neoplastic fixation and nonneoplastic changes in the prevertebral space.

Spontaneous thrombosis of a basilar artery traumatic aneurysm in a child

Traumatic aneurysms are rare and occur most commonly in young adults; however, the relative frequency in the pediatric population is high, owing to the low prevalence of congenital saccular aneurysms in children. Traumatic aneurysms typically involve the anterior circulation, and spontaneous thrombosis is uncommon; hence, surgery is usually necessary. We present a case of a posttraumatic aneurysm in a child that occurred after a fall from a large height and that spontaneously thrombosed.

Can radiologists accurately predict preepiglottic space invasion with MR imaging?

OBJECTIVE

The purpose of this study was to evaluate whether observers of MR imaging can accurately predict invasion of the preepiglottic fat (PEF) in patients with oropharyngeal and supraglottic laryngeal squamous cell carcinoma.

MATERIALS AND METHODS

For 41 patients with pathologically proven squamous cell carcinoma of the oropharynx and supraglottic larynx, we retrospectively analyzed their MR images for the presence or absence of PEF neoplastic invasion. Unenhanced T1-weighted, fat-suppressed T2-weighted, and contrast-enhanced fat-suppressed T1-weighted scans were analyzed independently by two neuroradiologists who were unaware of the surgical findings. Proof of diagnosis was determined by pathologic analysis, intraoperative assessment, or both.

RESULTS

Sixteen patients had neoplastic infiltration of the PEF. All infiltration was correctly predicted by the two observers of MR imaging, resulting in a sensitivity of 100%. Twenty-five patients had no invasion of the PEF by pathologic or surgical evaluation or both. Of these patients, negative findings were correctly predicted on MR imaging in 21 patients, whereas positive findings were incorrectly predicted on MR imaging in the remaining four patients, resulting in a specificity of 84% and an accuracy of 90%. In two of the four false-positive cases, effacement of the fat in the preepiglottic space by large tumors was mistaken for invasion. In a third patient, spread to the paraglottic space was mistaken for PEF extension. In the fourth false-positive case, glandular tissue along the ventral epiglottis may have been mistaken for tumor. The observers believed that unenhanced sagittal and axial T1-weighted scans were particularly useful because fat saturation artifacts may degrade T2-weighted and contrast-enhanced T1-weighted scans.

CONCLUSION

Unenhanced T1-weighted MR images are highly sensitive for neoplastic infiltration of the preepiglottic space in patients with oropharyngeal and supraglottic laryngeal carcinoma who are at risk for such spread. Identification of PEF invasion is important because it affects prognosis and may affect surgical management.

Synovial sarcomas of the head and neck: MR findings

OBJECTIVE

MR images of six synovial sarcomas of the head and neck were evaluated to determine their characteristic sites of origin, size, extent, intensity, and contrast enhancement. It was hoped that specific MR characteristics could be defined to suggest this entity.

CONCLUSION

A nonmucosal head and neck mass that is isointense to gray matter on T1-weighted images and is well defined yet heterogeneous, with septations, hemorrhage, cysts, calcification, or multilocularity, should raise suspicion of a synovial sarcoma. Because the appearance of synovial sarcomas varies and other masses may appear similar, no specific imaging characteristics define the entity.

Adenoidal width and HIV factors

PURPOSE

To determine the factors that correspond to adenoidal hypertrophy, often prominent in human immunodeficiency virus (HIV)-positive patients.

METHODS

The sagittal T1-weighted MR images of 21 HIV-positive patients (age range, 25 to 50 years; mean, 37 years) and 21 healthy control subjects (age range, 24 to 55 years; mean, 35 years) were reviewed blindly and independently by two radiologists who measured the maximal dimension of the nasopharyngeal lymphoid tissue. Twenty-six additional HIV-positive patients were combined with the original 21 HIV-positive patients, and the hematologic studies of these 47 patients were compared with the adenoidal measurements to assess whether a relationship existed between nasopharyngeal prominence and hematocrit, white blood cell count, and CD4 count.

RESULTS

Mean adenoidal width was 6.76 mm (SD, 5.82) in the HIV-positive population, but was only 3.36 mm (SD, 2.48) in the age-matched control group. Age and HIV status correlated with nasopharyngeal width measurements. No relationship between adenoidal width and hematocrit, CD4 count, or white blood cell count was evident.

CONCLUSION

After correcting for age, we found that adenoidal lymphoid tissue is more abundant in HIV-positive persons than in control subjects. The hematologic ramifications of this finding remain uncertain.

Clinical and economic impact of incidental thyroid lesions found with CT and MR

PURPOSE

To estimate the prevalence and the clinical and economic consequences of management strategies for thyroid lesions detected incidentally on cross-sectional imaging of the head and neck.

METHODS

Two hundred consecutive CT scans and 200 consecutive MR images of the neck performed over a 1-year period in patients being examined for other purposes were reviewed retrospectively to determine the prevalence of unexpected thyroid lesions. After excluding patients with prior thyroidectomies, known thyroid disease, and inadequate examinations, 231 imaging studies were analyzed.

RESULTS

Incidental thyroid lesions were originally reported in 14 (6%) of the 231 patients, but an additional 22 (9.5%) were found on retrospective review for a total of nearly 16% (36 of 231). Six of the 36 patients received further workup, consisting of nuclear medicine scintigraphy (n = 3), sonography (n = 3), thyroid function tests (n = 5), fine-needle aspiration (n = 4), and thyroid lobectomy (n = 1). Final diagnoses, obtained in four of the six patients, included three multinodular goiters and one follicular adenoma. Two patients, one with nondiagnostic findings at fine-needle aspiration and a second with normal thyroid function test results, are being followed up. The mean cost of the workup and treatment per examined patient was $1158.

CONCLUSION

Incidental thyroid lesions are frequently present and often overlooked on cross-sectional images of the neck in patients being examined for other reasons. The cost of pursuing a workup of these lesions and their high prevalence in the population raise questions regarding appropriate management strategies.

Overlooked metastatic lesions of the occipital condyle: a missed case treasure trove

Radiologic images obtained in nine patients with known primary cancer and occipital or head and neck pain were retrospectively reviewed after having been initially interpreted as normal. Imaging studies included head computed tomography (CT) in five cases, brain magnetic resonance (MR) imaging in six cases, cervical spine CT and MR imaging in five cases, radiography in two cases, and scintigraphy in two cases. This reevaluation demonstrated lesions of the occipital condyles in all patients. Seven patients had unilateral occipital condyle masses, and two patients had bilateral condyle lesions. Lesions were found to either involve only the occipital condyle (n = 4), extend to the adjacent occipital bone (n = 3), or extend to the ipsilateral clivus (n = 2). Misinterpretation of radiologic examinations resulted in an average delay in diagnosis of 10 weeks from the onset of symptoms to definitive therapy (irradiation). It is important to evaluate the occipital condyles in all patients with occipital pain, especially those with cancer. Neoplastic disease involving the occipital condyles is not common; however, it is frequently missed at imaging. Careful review of unenhanced sagittal and axial T1-weighted MR images and of the inferior sections from axial head CT studies will make it possible to avoid this potential pitfall.

In situ hybridization for Aspergillus and Penicillium in allergic fungal sinusitis: a rapid means of speciating fungal pathogens in tissues

Allergic fungal sinusitis (AFS) is a serious form of sinonasal fungal disease that is commonly associated with Aspergillus or Dematiaceous fungi. This study was performed to determine the incidence of Aspergillus or Penicillium in AFS by using in situ hybridization (ISH) for Aspergillus and Penicillium ribosomal RNA (rRNA). The Fontana-Masson melanin stain (FMMS) was also used to detect pigmented fungi (A. niger and Dematiaceous fungi). ISH was performed on 26 patients: 17 AFS cases with histologic evidence of fungi, 5 AFS cases without histologic evidence of fungi, 3 cases of invasive fungal sinusitis (IFS), and 1 case of fungus ball. Nine AFS specimens with histologic evidence of fungi were ISH positive. Positivity was also noted in two of three IFS cases, while no staining was seen in the fungus ball and in six AFS specimens without fungi demonstrable by silver stains. Six ISH-positive cases were FMMS positive, suggesting A. niger. Five ISH-negative AFS specimens were FMMS positive, suggesting Dematiaceous fungi. In summary, many AFS patients in our institution demonstrate Aspergillus/Penicillium organisms. Ancillary techniques may help identify fungi responsible for AFS if cultures are negative or not performed. ISH for rRNA is a useful means for rapidly speciating fungi in human tissues.

MR of thoracic cord compression caused by epidural extramedullary hematopoiesis in myelodysplastic syndrome

Spinal cord compression caused by extramedullary hematopoiesis is a rare complication of chronic anemic states, most frequently occurring in patients with beta-thalassemia. We report the MR appearance of extramedullary hematopoiesis resulting in cord compression in a patient with a myelodysplastic syndrome, which was isointense with the spinal cord on T1-weighted images and markedly hypointense on fast spin-echo T2-weighted images, and that demonstrated enhancement.

Gliomas: correlation of magnetic susceptibility artifact with histologic grade

PURPOSE

To determine whether magnetic susceptibility artifact on magnetic resonance (MR) images can be used to grade gliomas.

MATERIALS AND METHODS

Twenty-nine patients with gliomas were prospectively examined with spin-echo T1-weighted MR imaging without and with contrast material enhancement, spin-echo or fast spin-echo T2- and proton-density-weighted MR imaging, and gradient-echo T2*-weighted MR imaging. Images were reviewed by two neuroradiologists, and susceptibility artifacts in the tumor region were graded. Heterogeneity, mass effect, contrast enhancement, and necrosis were also graded. Tumors were graded according to the World Health Organization classification.

RESULTS

Increased susceptibility artifact was detected by at least one observer on gradient-echo MR images of 19 tumors. This feature was seen on only 10 of the spin-echo or fast spin-echo T2-weighted MR images of lesions. Fifteen neoplasms with increased susceptibility artifact detected on MR images by at least one observer were high-grade lesions (anaplastic astrocytoma or glioblastoma multiforme). Lesion susceptibility artifact detected on T2*-weighted MR images was associated with tumor grade (P < .05).

CONCLUSION

Susceptibility artifacts on T2*-weighted gradient-echo MR images appear to be valuable in the preoperative evaluation of gliomas.

Heterotopic brain in the pterygopalatine fossa

Heterotopic brain outside the cranial vault is uncommon. It occurs most frequently in the nasal region, although rests elsewhere in the aerodigestive tract have been reported. We describe a case of heterotopic brain in the pterygopalatine fossa.

Imaging of the thyroid gland

The thyroid gland is critical in regulating metabolic functions including cardiac rate and output, lipid catabolism, skeletal growth, and oxygen and heat production. Thus, patients with hormonally active thyroid abnormalities present with wide-ranging symptoms, requiring an understanding of the gland's hormonal functions. Radiological imaging assesses the pathophysiological affects of abnormal thyroid function as well as important morphological features. Nuclear scintigraphy provides functional information about the gland, whereas cross-sectional imaging-including ultrasound, CT, and MR-provide adjunctive anatomic information. These modalities also provide information about related structures in the neck. The embryology, anatomy, and physiology of the thyroid are discussed; congenital, autoimmune, inflammatory, metabolic, and neoplastic diseases are reviewed; and the diagnostic utility of radiological imaging is addressed.