Increased Water Content in Periventricular Caps in Patients without Acute Hydrocephalus.

BACKGROUND AND PURPOSE: Periventricular caps are a common finding on MR imaging and are believed to reflect focally increased interstitial water content due to dysfunctional transependymal transportation rather than ischemic-gliotic changes. We compared the quantitative water content of periventricular caps and microvascular white matter lesions, hypothesizing that periventricular caps associated with increased interstitial fluid content display higher water content than white matter lesions and are therefore differentiable from microvascular white matter lesions by measurement of the water content. MATERIALS AND METHODS: In a prospective study, we compared the water content of periventricular caps and white matter lesions in 50 patients using a quantitative multiple-echo, gradient-echo MR imaging water-mapping sequence. RESULTS: The water content of periventricular caps was significantly higher than that of white matter lesions (P = .002). Compared with normal white matter, the mean water content of periventricular caps was 17% ± 5% higher and the mean water content of white matter lesions was 11% ± 4% higher. Receiver operating characteristic analysis revealed that areas in which water content was 15% higher compared with normal white matter correspond to periventricular caps rather than white matter lesions, with a specificity of 93% and a sensitivity of 60% (P < .001). There was no significant correlation between the water content of periventricular caps and whole-brain volume (P = .275), white matter volume (P = .243), gray matter volume (P = .548), lateral ventricle volume (P = .800), white matter lesion volume (P = .081), periventricular cap volume (P = .081), and age (P = .224). CONCLUSIONS: Quantitative MR imaging allows differentiation between periventricular caps and white matter lesions. Water content quantification of T2-hyperintense lesions may be a useful additional tool for the characterization and differentiation of T2-hyperintense diseases.

Imaging Features of Hypertrophic Olivary Degeneration.

Hypertrophic olivary degeneration (HOD) is a unique form of transneuronal degeneration caused by a disruption of the dentato-rubro-olivary pathway, also known as the triangle of Guillain-Mollaret. The triangle of Guillain-Mollaret is involved in fine voluntary motor control and consists of both the inferior olivary nucleus and the red nucleus on one side and the contralateral dentate nucleus. Clinically, patients classically present with symptomatic palatal myoclonus. Typical magnetic resonance imaging findings include T2-hyperintensity and enlargement of the inferior olivary nucleus evolving over time to atrophy with residual T2-hyperintensity. In this article, we provide a case-based illustration of the anatomy of the Guillain-Mollaret-triangle and the typical imaging findings of hypertrophic olivary degeneration.

MRI Appearance of Intracerebral Iodinated Contrast Agents: Is It Possible to Distinguish Extravasated Contrast Agent from Hemorrhage?

BACKGROUND AND PURPOSE: Hyperattenuated cerebral areas on postinterventional CT are a common finding after endovascular stroke treatment. There is uncertainty about the extent to which these hyperattenuated areas correspond to hemorrhage or contrast agent that extravasated into infarcted parenchyma during angiography. We evaluated whether it is possible to distinguish contrast extravasation from blood on MR imaging. MATERIALS AND METHODS: We examined the influence of iodinated contrast agents on T1, T2, and T2* and magnetic susceptibility in a phantom model and an ex vivo animal model. We determined T1, T2, and T2* relaxation times and magnetic susceptibility of iopamidol and iopromide in dilutions of 1:1; 1:2; 1:4; 1:10; and 1:100 with physiologic saline solution. We then examined the appearance of intracerebral iopamidol on MR imaging in an ex vivo animal model. To this end, we injected iopamidol into the brain of a deceased swine. RESULTS: Iopamidol and iopromide cause a negative susceptibility shift and T1, T2, and T2* shortening. The effects, however, become very small in dilutions of 1:10 and higher. Undiluted iopamidol, injected directly into the brain parenchyma, did not cause visually distinctive signal changes on T1-weighted spin-echo, T2-weighted turbo spin-echo, and T2*-weighted gradient recalled-echo imaging. CONCLUSIONS: It is unlikely that iodinated contrast agents extravasated into infarcted brain parenchyma cause signal changes that mimic hemorrhage on T1WI, T2WI, and T2*WI. Our results imply that extravasated contrast agents can be distinguished from hemorrhage on MR imaging.

Subependymal Gray Matter Heterotopia.

BACKGROUND: A 31-year-old woman presented at the department of neurology with a history of seizures since childhood. About five years ago her seize pattern changed from generalized atonic attacks with asphyxia to simple partial attacks characterized by left hemiparesis and speech difficulties. These seizures occurred multiple times a day and typically lasted about a minute. The patient had a negative family history of epilepsy.

Lymphangioleiomyomatosis Presenting with Perirenal Hemorrhage.

Lymphangioleiomyomatosis (LAM) is a rare debilitating disease of unknown etiology, classically described as almost exclusively affecting women of childbearing age. The disease most commonly involves the lungs and is characterized by hamartomatous smooth muscle cell proliferations along blood vessels, airways and lymphatics. Most patients present with pulmonary symptoms, including shortness of breath, recurrent pneumothorax and pleural effusions. Extrapulmonary manifestations of LAM as the initial presentation of the disease are highly unusual. We present the case of a patient in whom LAM was incidentally discovered when the patient presented with retroperitoneal hemorrhage from a ruptured renal angiomyolipoma.

Stroke Versus Seizure - Perfusion Computerized Tomography in a Patient with Aphasia.

Both stroke and seizures have varied clinical presentations and their differentiation in the acute setting is not always straightforward. We present the case of a patient who presented at the emergency room with acute onset aphasia. Clinically acute ischemic stroke was suspected. Perfusion CT was performed and demonstrated cortical hypervascularity in the left partietotemporal region. Additional MRI and EEG were performed and a final diagnosis of postictal aphasia was made. This case illustrates that perfusion CT is not only a useful tool for acute stroke management, but can also aid in the detection of seizures in patients presenting with stroke-like symptoms.

Stafne Bone Cavity.

BACKGROUND: A 53-year-old male was referred to the department of maxillofacial surgery for the extraction of a destructed wisdom tooth. A preoperative orthopantomogram revealed a well delineated ovoid, radiolucent lesion at the left angle of the mandible. For further lesion characterization, a dental CT scan and MRI were performed.

CT features of groove pancreatitis subtypes.

Groove pancreatitis is a rare form of chronic pancreatitis affecting the pancreaticoduodenal groove, a potential space bordered by the pancreatic head, duodenum and common bile duct. Two forms of groove pancreatitis have been described: the segmental form, which involves the groove and the pancreatic head; and the pure form, which affects the groove only. Differentiation between groove pancreatitis and pancreatic head carcinoma can be difficult, both clinically and radiologically. In this article we present the clinical and imaging findings of two patients with pure and segmental groove pancreatitis respectively.

Cutaneous metastatic tuberculous abcess in a patient with cervico-mediastinal lymphatic tuberculosis.

Metastatic tuberculous abcess or tuberculous gumma is a rare form of cutaneous tuberculosis resulting from haematogenous spread from a non-cutaneous tuberculous focus. A 26-year old patient of Pakistani origin presented at our clinic with an abcess on his right thigh that had slowly grown over a period of two months to a total size of 30 cm. Based on clinical findings, microbiology, CT thigh and CT chest, our patient was diagnosed with a tuberculous abcess and cervico-mediastinal tuberculous lymphadenitis. Antituberculosis drugs were initiated. Cutaneous tuberculosis should be included in the differential diagnosis of chronic cutaneous abcesses, especially in patients from tuberculosis endemic nations.

Subpubic cartilaginous cyst: a rare cause of dysuria.

A subpubic cartilaginous cyst is a rare lesion that may present as a vulvar mass or rarely with dysuria. This condition occurs predominantly in multiparous postmenopausal women and is believed to be secondary to degenerative changes in the fibrocartilaginous disc of the symphysis pubis. The midline location, close relationship with the undersurface of the symphysis pubis and the cystic nature are the clues to the correct diagnosis.

Hemangiomatosis of the spleen in a patient with Klippel-trénaunay syndrome.

Klippel-Trenaunay syndrome is a rare disorder characterized by a triad of port-wine stains, varicose veins, and bony and soft tissue hypertrophy usually involving an extremity. Visceral involvement in Klippel-Trénaunay syndrome is rare, but has been described in the colon, small bowel, bladder, kidney, spleen, liver, mediastinum and brain. In this paper we present the case of a 45-year-old woman with Klippel-Trenaunay syndrome in whom routine physical examination unexpectedly revealed the presence of a left upper quadrant mass. Abdominal US, contrast enhanced CT and whole-body PET-CT demonstrated multiple large cystic lesions within a massively enlarged spleen. Based on the clinical history and imaging findings diffuse hemangiomatosis of the spleen was suspected. This diagnosis was confirmed by pathologic examination after splenectomy.

CT-imaging of lesser known or seen anatomical structures of the temporal bone.

Temporal bone anatomy is complicated on CT with many normal variants, of which some are infrequently seen or lesser known. The unaware radiologist can confuse them with pathology. Other lesser known normal variations are important to report because they can cause pathology. This paper illustrates in detail how to avoid such misinterpretations of anatomical structures.