Richard B. Noto

Low Event Rate for Stress-Only Perfusion Imaging in Patients Evaluated for Chest Pain

OBJECTIVES We sought to demonstrate the safety of stress-only perfusion imaging among patients with low to medium probability of coronary disease being evaluated for chest pain. BACKGROUND The need for performing rest in addition to stress perfusion imaging to confirm normalcy is due largely to defects created on the stress images by attenuation artifacts. A low cardiac event rate among patients undergoing stress-only imaging with attenuation correction (AC) would validate the safety of stress-only imaging. METHODS Patients with low to medium pretest probability for coronary artery disease (CAD) referred for chest pain evaluation from July 1, 1997 to July 1, 1999, were scheduled for a two-day stress/rest tomographic (single photon emission computerized tomography, or SPECT) perfusion imaging study with Tc-99m sestamibi. Patients were imaged on a variable angle camera with AC using Gd-153 scanning line sources (Vantage ADAC, Milpitas, California). If the stress scan was normal without AC or corrected with AC, the patient did not return for rest scan and was followed. RESULTS Seven hundred twenty-nine patients underwent stress-only imaging, and follow-up was obtained on 652 (89%) of those patients. There were 224 males and 428 females with mean age of 52 +/- 13 years. Mean follow-up was 22.3 +/- 6.4 months. The mean pretest probability was 37 +/- 24%. The non-AC images showed breast and/or diaphragmatic attenuation artifacts severe enough to have required the patient to return for rest imaging in 37% of patients, and all corrected completely with AC. During follow-up, there were two noncardiac deaths and no cardiac deaths. There was one myocardial infarction; three patients with progressive unstable angina underwent diagnostic coronary angiography showing significant CAD. The overall cardiac event rate was 0.6%. CONCLUSIONS These results support stress-only imaging in patients with low to medium probability for CAD as a safe, time- and cost-efficient imaging modality.

Sentinel node identification and the ability to detect metastatic tumor to inguinal lymph nodes in squamous cell cancer of the vulva

OBJECTIVES The goal of this study was to identify one or more inguinal sentinel nodes in patients with primary squamous cell carcinoma of the vulva and to determine the ability of the sentinel node to predict metastasis to the inguinal lymphatic basin. METHODS Techniques employing technetium-99m (Tc-99m) sulfur colloid and isosulfan blue dye were utilized to identify sentinel nodes in the inguinal lymphatic beds. Technetium-99m sulfur colloid was injected intradermally at the tumor margins 90-180 min preoperatively followed by a similar injection of isosulfan blue dye 5-10 min before the groin dissection. A handheld collimated gamma counter was employed to identify Tc-99m-labeled sentinel nodes. Lymphatic tracts that had taken up blue dye and their corresponding sentinel node were also identified and retrieved. A completion inguinal dissection was then performed. Each sentinel node was labeled as hot and blue, hot and nonblue, or cold and blue. The sentinel nodes were subjected to pathologic examination with step sections and nonsentinel nodes were evaluated in the standard fashion. RESULTS Twenty-one patients with a median age of 79 were entered onto protocol and a total of 31 inguinal node dissections were performed. A sentinel node was identified in 31/31 (100%) groin dissections with the use of Tc-99m. Isosulfan blue dye identified a sentinel node in 19/31 (61%) groin dissections. Surgical staging revealed 7 patients with stage I disease, 5 with stage II disease, 5 with stage III disease, and 4 with stage IV disease. Lymph nodes in 9 groin dissections were found to have metastatic disease, and in 4 of these dissections, the sentinel node was the only positive node. Lymph nodes in 22 groin dissections had no evidence of metastasis. No false-negative sentinel lymph nodes were obtained (sentinel node negative and a nonsentinel node positive). CONCLUSION Tc-99m sulfur colloid is superior to isosulfan blue dye in the detection of sentinel nodes in inguinal dissections of patients with vulvar cancer. A sentinel node dissection utilizing Tc-99m alone can identify a sentinel node in all inguinal dissections. Pathologic examination with step sections has shown the sentinel node to be an accurate predictor of metastatic disease to the inguinal nodal chain.

Isolated sentinel lymph node dissection with conservative management in patients with squamous cell carcinoma of the vulva: A prospective trial

OBJECTIVES Sentinel lymph node (SLN) dissections have a high sensitivity and negative predictive value for the detection of metastatic disease. The objective of this study was to examine the inguinal recurrence rate along with complication rates for patients undergoing inguinal SLN dissection alone for vulvar carcinoma. METHODS An IRB approved prospective study enrolled patients with biopsy proven squamous cell carcinoma of the vulva. Peritumoral injection of Tc-99 sulfur colloid and methylene blue dye was used to identify SLNs intraoperatively. Patients with SLNs negative for metastatic disease were followed clinically. Patients with metastasis detected in a SLN subsequently underwent a full groin node dissection followed by standard treatment protocols. RESULTS Thirty-six patients were enrolled onto study with 35 undergoing a SLN dissection. All SNL dissections were successful with a mean of 2 SLN obtained per groin. There were 24 patients with stage I disease, 8 stage II, 3 stage III and 1 stage IV. A total of 56 SLN dissections were performed with 4 patients found to have inguinal metastasis by SLN dissection. There were 31 patients with a total of 46 SLN dissections found to be negative for metastatic disease. The median follow-up has been 29 months (range 8 to 51) with 2 groin recurrences for a groin recurrence rate of 4.3% and a recurrence rate per patient of 6.4%. There have been no reports of groin breakdown, extremity cellulitis or lymphedema. CONCLUSIONS The recurrence rate for patients undergoing inguinal sentinel node dissection alone is low. These patients did not experience any complications as seen with complete groin node dissections. Sentinel lymph node dissection should be considered as an option for evaluation of inguinal nodes for metastatic disease.

Tc-99m MDP uptake in osteopoikilosis

A Tc-99m bone scan of a patient with classic roentgenographic findings of osteopoikilosis revealed multiple foci of increased activity that corresponded to many of the sclerotic foci on the roentgenograms. The authors presume that the abnormal bone scan in this patient reflects active osseous remodeling, similar to what has been observed in bone islands. Previous reports have emphasized the critical role of the radionuclide bone scan for distinguishing osteopoikilosis from osteoblastic bone metastases in patients with a known or suspected primary malignancy. In a young patient, an abnormal bone scan does not exclude the diagnosis of osteopoikilosis if the roentgenographic findings are characteristic of that entity.

A SPECT imaging study of MRI white matter hyperintensity in patients with degenerative dementia

We investigated the correlation between cortical perfusion and white matter hyperintensities on magnetic resonance images (MRI) of patients with dementia. The study included 40 subjects, each of whom had undergone both MRI and single-photon emission computed tomography (SPECT) studies as part of their diagnostic evaluation for degenerative dementia. Two neuroradiologists rated the MRI films for severity of periventricular white matter changes on a 0-5 point scale and severity of subcortical white matter changes on a 0-4 point scale. Twelve regions of interest from association cortex were sampled for the semiquantitative analysis of SPECT images. No relationship was found between these global MRI ratings and semiquantitative or qualitative SPECT findings. Dementia severity as measured by the Mini-Mental State Examination and the Clinical Dementia Rating was significantly correlated with SPECT, whereas age was significantly correlated with MRI ratings, particularly in the periventricular regions. These data support the view that cortical SPECT abnormalities are not associated with global MRI abnormalities in the subcortical and periventricular regions of patients with a clinical picture of degenerative dementia.

Single Photon Emission Computed Tomography, Magnetic Resonance Imaging Hyperintensity, and Cognitive Impairments in Patients With Vascular Dementia

Background. The relationship between subcortical hyperintensity (SH) on magnetic resonance imaging (MRI), cortical perfusion on single photon emission computed tomography (SPECT), and cognitive function is not well understood. The authors examined these relationships in individuals with vascular dementia (VaD), paying particular attention to frontal lobe function to determine whether the presence of SH on MRI was associated with frontal hypoperfusion on SPECT, which in turn would be associated with impairments of executive‐attention function. Methods. Patients with vascular dementia (n= 26) were assessed on neurocognitive tests and brain MRI and SPECT. SH volume was quantified from the axial T2‐weighted fluid attenuated inversion recovery MRI. Total counts of activation across voxels for 12 cortical regions of interest were determined from SPECT. Perfusion ratios of both total cortical and frontal activation relative to cerebellum activation were derived, and regression analyses were performed to determine the relationships between cognitive, MRI, and SPECT indices. Results. SH volume on MRI was significantly associated with frontal lobe perfusion, but not with global cortical perfusion as measured by SPECT. Frontal lobe perfusion did not consistently correlate with performance on measures of executive function, although both total and frontal perfusion ratios were significantly associated with other cognitive functions. Conclusions. These results suggest that a functional “disconnection” between the frontal lobes and subcortical structures does not fully account for the magnitude of global cognitive impairment in VaD. Cortical perfusion as measured by SPECT appears to be associated with cognitive performance, but not specifically executive‐attention dysfunction. Additional studies are needed to further examine the relationship between subcortical and cortical function in VaD.

SPECT brain imaging in chronic Lyme disease.

Objectives Lyme disease is an infectious disease that frequently involves the central nervous system, leading to cognitive and/or mood dysfunction. The basis for these symptoms remains to be defined but may be the result of a vasculitis or metabolic abnormality secondary to the infection. SPECT scans of the brain might provide an objective measure of abnormalities present in patients with otherwise difficult to objectify clinical findings. The objective of this study was to determine the frequency, location, and severity of abnormalities in SPECT scans of the brain of patients with chronic Lyme disease. Methods A total of 183 individuals who met the clinical definition of chronic Lyme disease underwent SPECT scanning of the brain using 99mTc and standard nuclear imagine techniques. Abnormalities of perfusion to affected areas of the brain were defined as mild, moderate, or severe. Results Of all patients, 75% demonstrated abnormalities in perfusion to various areas of the brain, most notably the frontal, temporal, and parietal lobes. Patients considered to be seropositive and those considered seronegative had similar rates, types, and severity of perfusion defects. Abnormalities of MRI of the brain were seen in 14% of patients. Treatment with antibiotics, especially those with intracellular-penetrating activity, resulted in resolution or improvement of abnormalities in 70% of patients over a 1- to 2-year period. Conclusions Brain SPECT scans are abnormal in most patients with chronic Lyme disease, and these scans can be used to provide objective evidence in support of the clinical diagnosis. The use of certain antibiotic regimens seems to provide improvement in both clinical status and SPECT scans.

Optimum imaging of colorectal metastases

Dramatic improvements in diagnostic imaging have developed with and enabled increasingly sophisticated treatments for metastatic colorectal cancer. Advances in therapeutic techniques, such as surgical resection and percutaneous therapies, demand that diagnostic imaging provide an accurate assessment of disease burden as well as precise localization. In this article, we present the current state‐of‐the‐art of diagnostic imaging for evaluation of metastatic colorectal cancer. J. Surg. Oncol. 2010;102:909–913.

American College of Radiology and Society of Nuclear Medicine and Molecular Imaging Joint Credentialing Statement for PET/MR Imaging: Brain

Founded in 1951, the Joint Commission, formerly known as the Joint Commission on Accreditation of Healthcare Organizations and, previous to that, the Joint Commission on Accreditation of Hospitals, is a United States–based nonprofit organization that accredits more than 20,000 health care organizations and programs in the United States. The Joint Commission requires that there be a credentialing system for delineating and granting privileges for every hospital physician. The Joint Commission does not specify those qualifications. Privileges are generally practice-specific and are not usually transferable from hospital to hospital. The granting of clinical privileges cannot and should not depend on a single criterion such as board certification or membership in a particular specialty society; other options, such as documented evidence of requisite training, relevant experience, judgment skills, and demonstrated current competence, should be available. It is the final responsibility of the hospital medical staff and hospital governing board to ensure that a physician meets a reasonable standard of competency. PET/MR imaging is an emerging complex hybrid imaging modality recently introduced into clinical practice (1–3). In June 2013, the American College of Radiology (ACR) and the Society of Nuclear Medicine and Molecular Imaging (SNMMI) charged a joint task force with developing a credentialing statement for physicians responsible for the oversight and interpretation of PET/MR imaging examinations. The task force has prepared this joint statement related to brain PET/MR imaging as the first in a planned series of credentialing statements covering all organ systems and clinical applications. This joint statement is intended to guide credentialing bodies that privilege physicians to oversee, supervise, and interpret brain PET/MR imaging for patient care in the United States.

Brain amyloid in preclinical Alzheimer's disease is associated with increased driving risk

Postmortem studies suggest that fibrillar brain amyloid places people at higher risk for hazardous driving in the preclinical stage of Alzheimers disease (AD).