Fernando Cesani

Revisiting MRI for appendix location during pregnancy

OBJECTIVE The purpose of this study is to determine the location of the appendix in pregnant patients by MRI and to investigate the possibility of gradual upward displacement of the appendix during pregnancy. CONCLUSION The gradual upward displacement of the appendix during pregnancy was confirmed. MRI can be used for determination of the appendix localization in pregnant patients. Further studies with a larger number of patients will be helpful to answer this clinically relevant question.

CD4 lymphocytes in the blood of HIV+ individuals migrate rapidly to lymph nodes and bone marrow: support for homing theory of CD4 cell depletion

The mechanism(s) by which human immunodeficiency virus (HIV) causes depletion of CD4 lymphocytes remains unknown. Evidence has been reported for a mechanism involving HIV binding to (and signaling) resting CD4 lymphocytes in lymphoid tissues, resulting in up‐regulation of lymph node homing receptors and enhanced homing after these cells enter the blood, and induction of apoptosis in many of these cells during the homing process, caused by secondary signaling through homing receptors. Supportive evidence for this as a major pathogenic mechanism requires demonstration that CD4 lymphocytes in HIV+ individuals do migrate to lymph nodes at enhanced rates. Studies herein show that freshly isolated CD4 lymphocytes labeled with 111Indium and intravenously reinfused back into HIV+ human donors do home to peripheral lymph nodes at rates two times faster than normal. They also home at enhanced rates to iliac and vertebral bone marrow. In contrast, two hepatitis B virus‐infected subjects displayed less than normal rates of blood CD4 lymphocyte migration to peripheral lymph nodes and bone marrow. Furthermore, the increased CD4 lymphocyte homing rates in HIV+ subjects returned to normal levels after effective, highly active antiretroviral therapy treatment, showing that the enhanced homing correlated with active HIV replication. This is the first direct demonstration of where and how fast CD4 lymphocytes in the blood traffic to tissues in normal and HIV‐infected humans. The results support the theory that the disappearance of CD4 lymphocytes from the blood of HIV+ patients is a result of their enhanced migration out of the blood (homing) and dying in extravascular tissues.

Spinal-cerebrospinal fluid leak demonstrated by radiopharmaceutical cisternography

Cerebrospinal fluid (CSF) leaks are known to occur under several conditions: lumbar puncture performed for contrast myelography, spinal surgery, spinal stab wounds, fracture of the thoracic spine, inadvertent spinal puncture during epidural anesthesia, traumatic lumbar meningocele, and bronchopleural subarachnoid fistula due to bronchogenic carcinoma. Spontaneous spinal leaks are uncommonly encountered in neurosurgical practice, but they are increasingly recognized as a cause of spontaneous intracranial hypotension. Most CSF leaks are located at the cervicothoracic junction or in the thoracic spine. The disease is often self-limiting. A CSF leak can be detected directly by accumulation of radioactivity outside the subarachnoid space or suggested indirectly by the rapid disappearance of tracer from the subarachnoid space and early appearance in the urinary bladder. In this paper we present two unusual cases of CSF leak identified by radiopharmaceutical cisternogram.

Sarcoid: An unusual mimicker of classic pulmonary embolus

A patient had both the clinical presentations and the ventilation-perfusion scan that simulated pulmonary embolism so closely that anticoagulant therapy was administered. Computed tomography of the chest and Ga-67 citrate scintigraphy identified hilar adenopathy due to sarcoidosis as the cause of a ventilation-perfusion mismatch.

Three-phase Tc-99m labeled RBC scintigraphy of a splenic hemangioma

A 46-year-old man presented with right upper quadrant pain with a clinical suspicion of cholelithiasis and was referred for an abdominal ultrasound (US). On US evaluation, the liver and gallbladder were normal. Incidentally noted a homogeneous, well demarcated, hyperechoic, 5-cm mass in the inferior portion of the spleen. A subsequent Tc-99m labeled RBC scan showed a 5-cm photopenic area in the inferior portion of the spleen on perfusion and early blood pool images. Subsequent filling in on delayed images with slightly increased uptake relative to surrounding splenic tissue was seen on the final images (85 min). Splenic hemangiomas are rare neoplasms, although they still represent the most common primary neoplasm of the spleen. The incidence of splenic hemangiomas ranges from 0.03-14% in autopsy studies.

Tc-99m sestamibi imaging of a pancreatic VIPoma and parathyroid adenoma in a patient with multiple type I endocrine neoplasia

Technetium-99m sestamibi is known to localize in primary malignant and metastatic tumors. Specifically, brain, breast, thyroid, parathyroid, lung, and kidney tumors have been imaged. The Verner Morrison syndrome, which is caused by excessive vasoactive intestinal peptide (VIP), consists of watery diarrhea, hypokalemia, and achlorhydria. This condition is rarely associated with multiple endocrine neoplasia. The authors present a case of multiple endocrine neoplasia type I with visualization of a pancreatic VIPoma and parathyroid adenoma with Tc-99m MIBI.

Pericardial effusion in primary hypothyroidism: Tc-99m sestamibi imaging

A 28-year-old woman was admitted to the hospital for an episode of syncope. On arrival, the patient was noticed to have an enlarged cardiac silhouette on chest x-ray. The ECG showed sinus bradycardia at 50 beats per minute. A resting myocardial perfusion study was performed after the injection of 20 mCi of Tc-99m sestamibi. The SPECT images show normal myocardial perfusion with a large pericardial effusion, best appreciated with planar images. Laboratory data showed a TSH of 284 mU/L, T 3 uptake 0.77, T 4 0.4 mcg/dl, and a free thyroxine index less than 0.31. An echocardiogram showed a moderate to severe (600 cc) pericardial effusion with normal left ventricular function. Pericardial effusion may be a frequent manifestation in myxedema, an advanced severe stage

Peritoneoscintigraphy using Tc-99m MAA for diagnosis of diaphragmatic disruptions in trauma patients.

The diagnosis of diaphragmatic disruptions secondary to blunt trauma is difficult because the patients are usually asymptomatic. Delay in recognition of this injury can be life threatening. The presence of previous pulmonary pathology makes the diagnosis even more difficult to establish. In this report, a diaphragmatic tear was diagnosed using intraperitoneal instillation of Tc-99m MAA.

Three-phase bone and Ga-67 scintigraphy in disseminated sporotrichosis

A 27-year-old man, who had been shoveling gravel in southern Texas for 3 years, had a history of papules and nodules in the left lateral wall of the abdomen. The lesions increased in number and severity with spread to other regions of the body. A punch biopsy of the right arm lesion revealed intracellular, round and cigar shaped budding yeast. The cultures grew Sporotrichum schenkii. Three-phase bone imaging and a Ga-67 scan defined the extent of the disease including involvement of the right tibia, left second metacarpal, and the left wrist joints, the latter two of which were not apparent on clinical examination.

Agenesis of the right lobe of the liver.

A 70-year-old man had hepatobiliary scintigraphy, which showed agenesis of the right lobe of the liver and hypertrophy of the left lobe. There was no scintigraphic evidence of emptying of the radiotracer into the small bowel. Agenesis of the right lobe of the liver is an extremely rare congenital an