Marion A. Hughes

Imaging of cerebritis, encephalitis, and brain abscess.

Imaging plays an important role in the diagnosis and treatment of brain abscess, pyogenic infection, and encephalitis. The role of CT and MRI in the diagnosis and management of pyogenic brain abscess and its complications is reviewed. The imaging appearances of several common and select uncommon infectious encephalitides are reviewed. Common causes of encephalitis in immunocompromised patients, and their imaging appearances, are also discussed. When combined with CSF, serologic studies and patient history, imaging findings can suggest the cause of encephalitis.

MRI Findings in Patients with a History of Failed Prior Microvascular Decompression for Hemifacial Spasm: How to Image and Where to Look

BACKGROUND AND PURPOSE: A minority of patients who undergo microvascular decompression for hemifacial spasm do not improve after the first operation. We sought to determine the most common locations of unaddressed neurovascular contact in patients with persistent or recurrent hemifacial spasm despite prior microvascular decompression. MATERIALS AND METHODS: Eighteen patients with a history of a microvascular decompression presented with persistent hemifacial spasm. All patients underwent thin-section steady-state free precession MR imaging. Fourteen patients underwent repeat microvascular decompression at our institution. Images were evaluated for the following: the presence of persistent vascular compression of the facial nerve, type of culprit vessel (artery or vein), name of the culprit artery, segment of the nerve in contact with the vessel, and location of the point of contact relative to the existing surgical pledget. The imaging findings were compared with the operative findings. RESULTS: In 12 of the 18 patients (67%), persistent vascular compression was identified by imaging. In 11 of these 12 patients, the culprit vessel was an artery. Compression of the attached segment (along the ventral surface of the pons) was identified in most patients (58%, 7/12). The point of contact was proximal to the surgical pledget in most patients (83%, 10/12). The imaging interpretation was concordant with the surgical results regarding artery versus vein in 86% of cases and regarding the segment of the nerve contacted in 92%. CONCLUSIONS: In patients with persistent hemifacial spasm despite microvascular decompression, the unaddressed vascular compression is typically proximal to the previously placed pledget, usually along the attached segment of the nerve. Re-imaging with high-resolution T2-weighted MR imaging will usually identify the culprit vessel.

Optimal timing of first posttreatment FDG PET/CT in head and neck squamous cell carcinoma

The optimal timing for the initial posttreatment fluorodeoxyglucose (FDG) positron emission tomography (PET)/CT scan after definitive treatment of head and neck squamous cell carcinoma (HNSCC) is unclear.

Psammomatoid and trabecular juvenile ossifying fibroma: two distinct radiologic entities

OBJECTIVE Evaluate and compare the radiologic features of psammomatoid versus trabecular variants of juvenile ossifying fibromas. STUDY DESIGN Twelve of fifteen cases of juvenile ossifying fibroma of the craniofacial bones, retrieved from our pathology archives for the period between 2002 and 2013, had available preoperative computed tomography (CT) scans. The radiologic features of each case were analyzed and compared by two neuroradiologists and one oral and maxillofacial radiologist, each blinded to the histopathologic diagnosis. RESULTS Juvenile psammomatoid ossifying fibroma (JPOF) exhibited a ground-glass pattern, as an outer mantle with central radiolucency, a single mural nodule, or a solid homogeneous mass. The trabecular variant presented as a radiolucent lesion with irregular, scattered calcifications. Both variants displayed a well-defined border. CONCLUSION This study demonstrates that psammomatoid and trabecular juvenile ossifying fibromas exhibit unique radiologic features that allow for distinction between the two variants on CT studies.

Head CT Scan Overuse in Frequently Admitted Medical Patients

BACKGROUND Patients frequently admitted to medical services undergo extensive computed tomography (CT) imaging. Some of this imaging may be unnecessary, and in particular, head CT scans may be over-used in this patient population. We describe the frequency of abnormal head CT scans in patients with multiple medical hospitalizations. METHODS We retrospectively reviewed all CT scans done in 130 patients with 7 or more admissions to medical services between January 1 and December 31, 2011 within an integrated health care system. We calculated the number of CT scans, anatomic site of imaging, and source of ordering (emergency department, inpatient floor). We scored all head CT scans on a 0-4 scale based on the severity of radiographic findings. Higher scores signified more clinically important findings. RESULTS There were 795 CT scans performed in total, with a mean of 6.7 (± SD 5.8) CT scans per patient. Abdominal/pelvis (39%), chest (30%), and head (22%) CT scans were the most frequently obtained. The mean number of head CT scans performed was 2.9 (SD ± 4.2). Inpatient floors were the major site of CT scan ordering (53.7%). Of 172 head CT scans, only 4% had clinically significant findings (scores of 3 or 4). CONCLUSIONS Patients with frequent medical admissions are medically complex and undergo multiple CT scans in a year. The vast majority of head CT scans lack clinically significant findings and should be ordered less frequently. Interdisciplinary measures should be advocated by hospitalists, emergency departments, and radiologists to decrease unnecessary imaging in this population.

MRI of the Trigeminal Nerve in Patients With Trigeminal Neuralgia Secondary to Vascular Compression.

OBJECTIVE Trigeminal neuralgia is a debilitating facial pain disorder, frequently caused by vascular compression of the trigeminal nerve. Vascular compression that results in trigeminal neuralgia occurs along the cisternal segment of the nerve. CONCLUSION Imaging combined with clinical information is critical to correctly identify patients who are candidates for microvascular decompression. The purpose of this article is to review trigeminal nerve anatomy and to provide strategies for radiologists to recognize important MRI findings in patients with trigeminal neuralgia.

Delayed Nasoseptal Flaps for Endoscopic Skull Base Reconstruction: Proof of Concept and Evaluation of Outcomes

Objectives To assess delayed nasoseptal flaps as a viable reconstructive option for sellar defects, evaluate postoperative vascularity of delayed nasoseptal flaps, and compare cerebrospinal fluid leak and surgery-specific complication rates of primary to delayed nasoseptal flaps. Study Design Case series with chart review. Setting University of Pittsburgh Medical Center. Subjects and Methods All patients undergoing transsellar approaches for skull base tumors from 2009 to 2013 were evaluated. In cases where the necessity of a vascularized reconstructive flap was made evident only after tumor resection, the nasoseptal flap was raised after tumor resection and/or cerebrospinal fluid leak development, thus constituting a delayed nasoseptal flap. Outcome measures include postoperative magnetic resonance imaging (MRI) findings, cerebrospinal leak rates, and complication rates. Results During this timeframe, 437 patients underwent transsellar approaches. Primary nasoseptal flaps were used to reconstruct 179 patients while 32 patients had delayed flaps. All available postoperative MRI scans of delayed nasoseptal flap patients maintained vascularity on examination of T1 postcontrast images. There was no significant difference in cerebrospinal fluid leak rate between primary (3.4%) and delayed flaps (3.1%) (P = .95). There was no significant difference in surgery-specific complication rates between primary flaps (10.6%) and delayed flaps (3.1%; P = .14). Logistic regression analysis demonstrated no significant effect of flap type, age, or sex on cerebrospinal fluid leak rates. Conclusion Delayed nasoseptal flaps are a viable reconstructive option for sellar skull base defects. They maintain vascularity as evidenced on postoperative MRI and are comparable to primary nasoseptal flaps with regard to cerebrospinal fluid leak rates and complication rates.

PET/CT for Head and Neck Squamous Cell Carcinoma: Should We Routinely Include the Head and Abdomen?

OBJECTIVE The purpose of our study was to determine the diagnostic and therapeutic yield of the head and abdomen portions of PET/CT scans of patients with head and neck squamous cell cancer (HNSCC) to determine whether these areas should be routinely included with PET/CT of the neck and chest. MATERIALS AND METHODS Patients with pathologically proven HNSCC who underwent full-body PET/CT were evaluated for metastases to the head, chest, and abdomen. Medical records were reviewed to determine whether the head and abdominal findings changed the clinical management, beyond the findings in the neck and chest. RESULTS Five hundred ninety-eight patients who underwent 1625 PET/CT scans were included. All studies included the head, neck, and chest. For 542 of 598 patients (91%), the PET/CT scans included the abdomen. Two of 598 patients (0.3%) had distant calvarial metastases. Neither of the calvarial metastases changed patient management. Twelve of 542 patients (2.2%) had abdominal metastases. For 10 of 542 patients (1.8%), the abdominal findings changed patient management. Thoracic metastases were found in 82 of 598 patients (13.7%). The total rate of distant metastases to the head and abdomen in patients with thoracic metastatic disease was 12.2% (10/82), whereas in patients without thoracic metastases, it was 0.8% (4/460). CONCLUSION Routine extension of PET/CT scans to include the head and abdomen in patients with HNSCC is not indicated. For patients without evidence of thoracic metastases, routine PET/CT examinations should include the neck and chest only.

Is Computed Tomography an Adequate Imaging Modality for the Evaluation of Juvenile Ossifying Fibroma? A Comparison of 2 Imaging Modalities (Computed Tomography and Magnetic Resonance Imaging)

PURPOSE Given the problems of overuse of medical technology and the current burden of health care cost in the United States, it is important to establish clear imaging guidelines to diagnose conditions such as juvenile ossifying fibroma (JOF). This study compared the efficacy of computed tomography (CT) and magnetic resonance imaging (MRI) in the evaluation of JOF and thus could aid establishing such guidelines. MATERIALS AND METHODS Radiologic criteria were established by 2 radiologists to compare the efficacy of CT and MRI in the evaluation of JOF. The following parameters were compared: presence of a well-defined corticated border, presence of a well-delineated internal calcified component, fluid-to-fluid levels, and anatomic extent of the lesion. Six patients diagnosed with JOF of the craniofacial bones from 2002 to 2013 had preoperative CT and MRI studies available for review. RESULTS After review of CT and MRI images, fluid-to-fluid levels and anatomic extent of the lesions were comparable on CT and MRI. However, the corticated borders and the internal calcified component were better defined on CT images, which also enabled for distinction between the 2 subtypes of JOF. No MRI characteristics were identified that allowed for this distinction. CONCLUSION Based on these findings, CT is an adequate and preferable imaging modality in the evaluation of JOF.

Lumbar discal cyst in an elite athlete

Our patient, a 22-year-old starting wide receiver for an NCAA Division I football team, presented with low back pain and sciatica. A lumbar-spine MRI without contrast demonstrated findings suspicious for discal cyst. The patient was referred for surgery, and the lesion was resected. The rarity of discal cyst makes it difficult to diagnose because most radiologists are not aware of the entity. An organized approach to diagnosis can facilitate appropriate management.